Uv-radiation-hardenable binder composition for magnetic recording media and photoinitiator mixture

专利摘要:
UV-curable binder compositions, coatings containing the binder compositions, photoinitiators suitable for use in such coatings, and magnetic recording media containing the UV-curable coatings are described.
公开号:KR20010075691A
申请号:KR1020017005849
申请日:1999-10-08
公开日:2001-08-09
发明作者:알베르트 콜；볼프강 라이히；아우구스트 레너；귄터 헤일；폴커 코흐；요세프 쉘블；칼-하인츠 뢰머；프란츠 바인가르트
申请人:프리드리히 베케비츠；엠테크 마그네틱스 게엠베하；
IPC主号:

专利说明:

FIELD OF THE INVENTION [0001] The present invention relates to a UV-radiation curable binder composition and a photoinitiator mixture for a magnetic recording medium.
[2] BACKGROUND ART [0002] Magnetic recording media are widely used for recording and reproducing audio and video information and data. The conditions that these media must meet are steadily increasing and require continued improvement in terms of magnetic and electroacoustics and also in terms of aging. Thus, in addition to very good recording and reproducing properties, magnetic recording media should have high mechanical stability and durability, and even under extreme use conditions such as high temperature and high humidity. To this end, the magnetic layer must be highly flexible, have high resilience, and have high tensile strength. In addition, in order to avoid a drop at the output level, a reduction in the coefficient of friction and an increase in abrasion resistance and wear resistance are required.
[3] These requirements are not generally satisfied simultaneously by a known two-layer magnetic recording medium comprising a magnetic material dispersed in a substrate material, typically an organic binder on a linear polyester film such as polyethylene terephthalate. Thus, many magnetic recording media have multiple layers.
[4] In addition to the one or more magnetic layers, there may also be intermediate or adhesion promoting layers and backing coatings and top layers. They serve, for example, to improve adhesion of the magnetic layer, to improve the mechanical properties of the tape and / or to prevent accumulation of electrostatic charges. The backcoating is intended, for example, to prevent adhesion between the layers of the tape, accumulation of electrostatic charges and / or creasing of the tape. The upper layer prevents abrasion of the magnetic layer to prevent the recording and reproducing apparatus from being damaged. The interlayer, in particular the adhesion promoting layer, is intended to ensure the uniformity of the magnetic layer by increasing the mechanical load bearing capacity on the tape and improving the adhesion.
[5] A known problem of multilayer magnetic recording media, particularly magnetic tapes, is the accumulation of electrostatic charges resulting from friction and charge separation during rewinding and unwinding. It is also known that carbon black dispersed in magnetic recording media can be used to avoid the accumulation of such electrostatic charges. When carbon black is used directly in the magnetic layer, generally good electrostatic properties are obtained, but at the same time the residual induction deteriorates. Therefore, in order to avoid such a result, carbon black is generally used as a layer on the back surface of the substrate or as a component of an adhesion promoting layer between the substrate material and the magnetic layer. The binder used in such an adhesion promoting or primer layer should sufficiently disperse both carbon black and additional pigments such as CrO ₃ , CaCO ₃ and the like which are used as additives as required.
[6] Various bonding agents have been proposed as base materials for the adhesion promoting layer. When a thermoplastic resin is used as the binder, the application of the magnetic coating material, which is generally dispersed in a considerable amount of solvent, causes the previously formed adhesion promoting layer to swell or dissolve by the solvent so that the coating becomes uneven and the magnetic layer There is a problem that it is not obtained. For thermosetting or chemically curable resins, a relatively long cure time is a problem. Thus, in general these resins can not be used in conventional continuous production processes for magnetic tapes today. Therefore, in recent years, a radiation curing process has become very important. Compared to chemical or thermal curing, irradiation curing has many advantages, such as the reduction of raw materials, the reduction of environmental pollution and energy, and the high curing rate and little thermal stress of the substrate, since solvent-free or low- .
[7] The irradiation curing of the binder used for the adhesion promoting layer is generally carried out by an electron beam. A disadvantage of such a curing process is that it requires a large space, high safety-related costs and high maintenance costs of the unit used. Therefore, it is preferable to use UV irradiation to cure the layer in the magnetic recording material layer. However, many problems arise. Since the binder composition used as the primer layer or adhesion promoting layer is generally highly colored, preferably colored with carbon black, the curing rate is greatly reduced compared to electron beams, long residence times are required for crosslinking, It only happens incompletely. Attempts to overcome this problem by increasing the double bond concentration in the binder or by reducing the molecular weight of the binder component generally resulted in deteriorating performance, for example shrinkage of the material during irradiation. This causes wrinkling of the substrate, which results in useless use of the magnetic recording medium. In addition, many binder compositions conventionally used for UV curing are not suitable for dispersion of carbon black and / or other pigments. Generally, thereafter flocculation and speckling occur.
[8] US-A 3,874,906 discloses a method of coating various substrates such as paper, metal, plastic and cellulose using a radiation curable composition containing polyester acrylate and N-vinyl pyrrolidone as viscosity reducing additives . The use of these radiation curable binders in pigment-containing coatings is not disclosed.
[9] US-A 4,129,709 describes radiation curable coatings containing urethane acrylate oligomers, N-vinyl pyrrolidone and acrylates. Of these additives for coating materials, pigments and carbon black are also very commonly referred to. However, there is no use for pigment-containing coatings, in particular for UV-curable, carbon black-containing coatings.
[10] US-A 4,348, 427 describes a method of coating various surfaces, for example wood, plastics, etc., with an irradiating curable coating. They contain at least one compound selected from epoxy acrylates, polyester acrylates and urethane acrylates, and at least one N-vinyl amide of a carboxylic acid, a sulfonic acid or a phosphonic acid. These coating materials can be crosslinked by UV irradiation at a wavelength of 200 to 400 nm in the presence of a photoinitiator. Coatings containing carbon black are not described in this document.
[11] EP-A 0 559 135 describes radiation curable compositions containing the following components:
[12] a) oligomers selected from epoxy acrylates, polyester acrylates, polyurethane acrylates and mixtures thereof,
[13] b) N-vinylformamide and, if desired, further monofunctional, effervescent, or multifunctional vinyl or acryloyl monomers. These compositions are described as being suitable for colored and non-colored coatings. However, suitable pigments, especially carbon black, are not described in this document.
[14] EP-A 0 632 111 has a description similar to EP-A 0 559 135.
[15] Radical Curing in Polymer Science and Technology, Volume 4, page 216 et seq., Elsevier 1993, discloses that a monofunctional monomer, such as N-vinylpyrrolidone and N-vinylcaprolactam, ≪ / RTI > acrylate as a reactive diluent.
[16] EP-A 0 033 897 describes a process for preparing polyurethane elastomers suitable for UV curing with an alpha, beta -ethylenically unsaturated double bond. These polyurethane elastomers can be used for the production of moldings, laminates, adhesives, coating materials, and magnetic tapes. Mixtures of these polyurethane acrylates with further [alpha], [beta] -ethylenically unsaturated compounds, especially N-vinylamides, N-vinyl lactams and vinyl- and allyl-substituted heteroaromatic compounds are not described in this document. The use of pigment-containing, especially carbon black-containing coatings is likewise not described.
[17] EP-A 0 169 524 describes a magnetic recording medium in which a magnetic material is dispersed as a binder in a polyurethane elastomer having a composition substantially corresponding to that of the polyurethane elastomer described in EP-A 0 033 897. The magnetic recording medium does not have a pigment-containing or carbon black-containing priming layer between the substrate and the magnetic layer. Carbon black is only generally mentioned as an additive for the magnetic layer only, and an embodiment containing a carbon black-containing magnetic layer is not described. The magnetic recording layer is cured by an electron beam. In fact, in the detailed description, the possibility for slight pre-polymerization of the coating material by UV light is very generally mentioned, in which case conventional photoinitiators are required. However, no individual photoinitiator is mentioned.
[18] DE-A 34 18 482 describes a magnetic recording medium comprising a non-magnetic substrate material and at least one magnetic layer, wherein the binder of the magnetic layer is cured by means of an electron beam. The binder comprises 60 to 100% by weight of a polyurethane acrylate polymer having an unsaturated double bond and a further , - ethylenically unsaturated compound 0 selected from an acrylate monomer, an acrylate prepolymer and / or an N- To 40% by weight. Polyurethane acrylates have an average of more than 2 and less than 4 acrylate groups per average molecule. Magnetic recording media having a priming layer between the substrate and the magnetic layer are not mentioned. The use of the binder used in the magnetic layer to disperse the carbon black is likewise not mentioned. The use of UV light is only mentioned for a slight prepolymerization of the coating material, in which case a conventional, highly absorbent photoinitiator is required. Again, no suitable photoinitiator is described.
[19] DE-A 34 28 943 describes magnetic recording media comprising a substrate, a priming coating on said substrate and a magnetic coating on the priming coating. This priming coating is obtained by dispersing the carbon black in the irradiating curable coating and irradiating the resulting dispersion. The coating material comprises, as a major component, at least two compounds selected from the following compounds:
[20] A) a compound having a molecular weight of 5000 or more and having two or more irradiation-curable unsaturated double bonds,
[21] B) a compound having a molecular weight of at least 400 but less than 5000 and containing at least one irradiation-curable unsaturated double bond, and
[22] C) A compound having a molecular weight of less than 400 and containing at least one irradiation-curable unsaturated double bond.
[23] N-vinylamides, N-vinyl lactams or coatings containing vinyl- and allyl-substituted heteroaromatic compounds are not described. It is generally stated that the carbon black-containing coating material of the priming coating can be cured by UV irradiation, but conventional sensitizers can be used, and in the embodiment curing is carried out solely by electron beams . Photoinitiator mixtures are likewise not mentioned in this document.
[24] Many photoinitiators are known to cure the coating material by UV irradiation. An overview of the various photoinitiators can be found, for example, in Radiation Curing in Polymer Science and Technology, Volume 2, Photoinitiating systems, Elsevier 1993]. Suitable photoinitiator mixtures for curing carbon black containing coatings are not described in this document.
[25] DE-A 40 25 386 describes photoinitiators of the acylphosphine oxide type and methods of curing free radically polymerizable materials, coatings and printing inks by UV irradiation in the presence of such photoinitiators. Acylphosphine oxides can be combined with other photoinitiators such as ketal, benzophenone or thioxanthone. The curable material may be transparent or contain organic or inorganic pigments.
[26] DE-A 42 40 964 discloses a photopolymerizable material containing arene bisphosphine oxide and a photoinitiator thereof. Mixtures of arene bisphosphine oxide with other photoinitiators may also be used.
[27] EP-A 0 184 095 describes bisacylphosphine oxides and their use as photoinitiators and photopolymerizable materials. Mixtures of these bisacylphosphine oxides with other photoinitiators are only mentioned very generally.
[28] EP-A 0 413 657 describes mono- and diacylphosphine oxides and photopolymerizable compositions containing them. Mixtures of other photoinitiators, such as benzophenone, acetophenone derivatives, benzoin ethers or benzyl ketals, may also be used.
[29] EP-A 0 495 751 describes bisacylphosphines and photopolymerizable compositions containing them. Mixtures with further photoinitiators or photosensitizers are also very generally mentioned.
[30] DE-A 38 26 947 describes thioxanthone derivatives having an alkylphenon group at the same time, and photopolymerizable binder systems containing these derivatives as photoinitiators. Such binder systems are conventional finishing or polymer coating and printing inks and preferably colored systems. The combination of these photoinitiators and conventional photoinitiators is only generally mentioned.
[31] The use of photoinitiator mixtures containing acylphosphine oxides or sulfides, alpha-cleavers and H-abstractors and their use in carbon black-containing UV-curable coatings is described in the literature .
[32] DE-A 42 31 579 describes their use in alkyl bisacylphosphine oxide photoinitiators and photopolymerizable compositions. These compositions may be radiation curable aqueous polymer dispersions, and conventional pigments and carbon blacks are referred to as additives. The bisacylphosphine oxide may be a known photoinitiator such as benzophenone, acetophenone derivatives, benzoin ethers, benzylketal, monoacylphosphine oxides, furthermore bisacylphosphine oxides, peresters or titanocenes. It can also be used in the form of a mixture. No photoinitiator mixtures containing more than two components and containing one or more acylphosphine oxides or sulfides, alpha -cutting agents and H-extracting agents are described. No mention is made in the examples of photoinitiator mixtures comprising three different photoinitiators. There is also no example for a carbon black containing UV-curable coating.
[33] EP-A 0 615 980 discloses a process for curing an ethylenically unsaturated polymerizable compound in the presence of a bisacylphosphine oxide photoinitiator. Ethylenically unsaturated compounds can be used in the form of radiation curable aqueous prepolymer dispersions, and carbon black as an additive to the dispersion is generally described. Mixtures of bisacylphosphine oxide photoinitiators with other photoinitiators such as benzophenone, acetophenone derivatives, benzoin alkyl ethers and benzyl ketals are also very generally described. No photoinitiator mixtures containing acylphosphine oxides or sulfides, alpha -cutting agents and H-extracting agents are described. Also, no examples of carbon black containing UV-curable coatings are mentioned.
[34] EP-A 0 446 175 contains a) 100 parts of mono- or diacylphosphine oxide,
[35] b) 10 to 70 parts of -hydroxyacetophenone and
[36] c) 10 to 70 parts of benzophenone.
[37] They are particularly suitable for UV curing coatings (white coatings) colored with TiO ₂ . The use of them in carbon black-containing UV-curable coatings is not described. The use of photoinitiator mixtures containing acylphosphine oxides or sulfides, alpha -cutters and H-extractants, and their use in carbon black-containing UV-curable coatings is not disclosed in the publication.
[1] The present invention relates to a UV-curable binder composition, a coating containing the binder composition, a photoinitiator mixture suitable for use in the coating, and a magnetic recording medium containing the UV-curable coating.
[38] It is an object of the present invention to provide a novel UV-curable binder composition. The composition should be suitable for use in pigment-containing coatings, especially carbon black-containing coatings. Another object of the present invention is to provide a photoinitiator mixture for use in a pigment-containing, especially carbon black-containing coating. The carbon black-containing coating material should likewise be UV-curable, and particularly suitable as a priming layer for magnetic recording media.
[39] The inventors have surprisingly found that the first object is achieved by a UV-curable binder composition comprising the following components:
[40] a) at least one polyurethane acrylate having an average molecular weight of 10 000 to 80,000 and an average of 4 to 15 UV-curable , -ethylenically unsaturated double bonds per molecule,
[41] b) at least one compound having a molecular weight of from 254 to 1000 and three UV-curable , -ethylenically unsaturated double bonds per molecule,
[42] c) at least one compound having a molecular weight of from 170 to 1000 and two UV-curable alpha, beta -ethylenically unsaturated double bonds per molecule,
[43] d) at least one , - ethylenically unsaturated compound selected from N-vinyl amide, N-vinyl lactam, vinyl- and allyl-substituted heteroaromatic compounds and mixtures thereof, and
[44] e) optionally, at least one ester of an alpha, beta -ethylenically unsaturated monocarboxylic acid and an aliphatic or cycloaliphatic C ₁ to C ₂₀ monoalcohol.
[45] This is preferably a binder composition comprising the following components:
[46] - 0.003 to 0.015 mol of one or more polyurethane acrylates a),
[47] - 0.2 to 1.5 mol of one or more compounds b),
[48] - 0.2 to 1.8 moles of one or more compounds c),
[49] - 0.1 to 4.0 mol, preferably 0.3 to 4.0 mol, of at least one , - ethylenic series selected from N-vinylamides, N-vinyllactams, vinyl- and allyl-substituted heteroaromatic compounds and mixtures thereof Unsaturated compounds d), and
[50] - 0 to 4.0 moles of at least one ester of an alpha, beta -ethylenically unsaturated monocarboxylic acid with an aliphatic or cycloaliphatic C ₁ -C ₂₀ monoalcohol.
[51] The content of the UV-curable , - ethylenically unsaturated double bond is preferably about 2.5 to 7.0 moles, more preferably 4.0 to 6.0 moles per 1000 g of the binder composition.
[52] The average double bond functional groups are preferably 1.8 or less, preferably 1.6 or less, per molecule based on components a) to e). The average double bond functional group is preferably at least 0.3 mol, preferably 0.5 mol, per molecule based on components a) to e).
[53] Component a)
[54] The polyurethane acrylate a) preferably has a number average molecular weight of about 10,000 to 80,000, preferably about 15,000 to 50,000.
[55] The polyurethane acrylate a) preferably consists of the following components:
[56] A) at least one compound having two or more terminal isocyanate groups selected from a diisocyanate, an isocyanate prepolymer, a polyisocyanate, and mixtures thereof,
[57] B) at least one compound having a molecular weight of from 146 to 3000 and at least one , -Ethylenically unsaturated double bond and at least two hydroxyl groups per molecule,
[58] C) at least one compound having at least one , - ethylenically unsaturated double bond and at least two hydroxyl groups per molecule,
[59] D) one or more polymers having two or more hydroxyl groups per molecule,
[60] E) optionally, compounds which differ from A) to D) and which have at least two active hydrogen atoms per molecule and which have a diol, an amine having at least two primary and / or secondary amino groups per molecule, an amino alcohol, , Polyol, water, and mixtures thereof.
[61] Preferred compounds A) having two or more terminal isocyanate groups are selected from compounds having 2 to 5 isocyanate groups, isocyanate prepolymers having an average of 2 to 5 isocyanate groups, and mixtures thereof. These include, on the one hand, organic di-, tri- and polyisocyanates.
[62] Suitable diisocyanates A) include, for example, tetramethylene diisocyanate, hexamethylene diisocyanate, 2,3,3-trimethylhexamethylene diisocyanate, cyclohexylene 1,4-diisocyanate, dicyclohexylmethane diisocyanate, iso 1,4-diisocyanate, toluene 2,4- and 2,6-diisocyanate, and isomer mixtures thereof, naphthylene 1,5-diisocyanate, diphenylmethane 2,4- and 4 , 4'-diisocyanate, and mixtures thereof. Suitable triisocyanates A) are, for example, triphenylmethane 4,4 ', 4 " -triisocyanates. More preferred are prepolymers having two or more free isocyanate groups, derived from two or more of the same or different diisocyanates and the diols and polydiols mentioned below. Preferred are diphenylmethane 2,4- and 4,4'-diisocyanate, isophorone diisocyanate, toluene 2,4- and 2,6-diisocyanate, dicyclohexylmethane diisocyanate, and mixtures thereof.
[63] Isocyanate prepolymers having a number average molecular weight of about 10,000 or less, preferably about 500 to 3000, are also suitable. These are obtained, for example, by the addition reaction of the isocyanate with a polyfunctional hydroxyl or an amino-containing compound. Polyisocyanates which are based on toluene diisocyanate, hexamethylene diisocyanate and / or isophorone diisocyanate and formed by the addition of a diol or a triol or by formation of a biuret, uretdione or isocyanurate Is preferably used. Suitable diols and triols are described below as component E).
[64] Polyisocyanates and one or more monofunctional compounds commonly used to control isocyanate group content, such as methanol, ethanol, n-propanol, isopropanol, n-butanol, tert-butanol, cyclohexanol, With one or more aliphatic, cycloaliphatic or aliphatic monoalcohols such as isopropanol, is also preferred. Such a reaction product preferably has one or more isocyanate groups per molecule. The reaction product of polyisocyanate with phthalimide or caprolactam is also preferred.
[65] The compounds of component A) may be used individually or as an analog of the mixture.
[66] Suitable compounds B) having one or more alpha, beta -ethylenically unsaturated double bonds and two or more hydroxyl groups can be prepared, for example, by reacting an epoxide compound having two or more epoxide groups with an alpha, beta -ethylenically unsaturated mono- and Dicarboxylic acids and their anhydrides. Suitable epoxide compounds and their reaction products are described, for example, in DE-A 21 64 386, which is incorporated herein by reference in its entirety. The diepoxide compounds used are, for example, polyalkylene glycols such as bisphenol A diglycidyl ether, resorcinol diglycidyl ether, 1,4-butanediol diglycidyl ether, polyethylene glycol, polypropylene glycol Diglycidyl ether of glycols, copolymers of ethylene oxide and propylene oxide, diglycidyl ether of phthalic anhydride and maleic anhydride, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 4-epoxy-6-methylcyclohexylmethyl 3,4-epoxy-6-methylcyclohexanecarboxylate, dicyclopentadiene diepoxide, and mixtures thereof. Suitable epoxide compounds also include conventional epoxy resins such as phenol and cresol epoxy novolak, glycidyl ether of phenol / aldehyde adduct, glycidyl ether of phenol / hydrocarbon novolac, glycidyl ether of aliphatic diol , Aromatic glycidyl amines, heterocyclic glycidyl imides and glycidyl amides, glycidyl esters and the like. Suitable alpha, beta -ethylenically unsaturated mono- and dicarboxylic acids for the reaction with such epoxide compounds are, for example, crotonic acid, fumaric acid, maleic acid, maleic anhydride, tetrahydrophthalic acid, tetrahydrophthalic anhydride, Methacrylic acid, and mixtures thereof. Optionally, the epoxide may be reacted with an acid mixture comprising at least one of the foregoing alpha, beta -ethylenically unsaturated carboxylic acid and at least one saturated mono- and / or dicarboxylic acid. Suitable saturated carboxylic acids are, for example, formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, malonic acid, succinic acid and mixtures thereof. By using mixtures of saturated and unsaturated mono- and / or dicarboxylic acids, the molecular weight and double bond content of compound B) can vary within wide limits. Generally, the molar ratio of epoxide to carboxyl groups is from about 1: 0.9 to 1: 1.1.
[67] Suitable compounds B) are also the reaction products of saturated dicarboxylic acids with , - ethylenically unsaturated glycidyl compounds. Suitable dicarboxylic acids are, for example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid and the like and mixtures thereof. For example, allyl glycidyl ethers can be used as olefinically unsaturated glycidyl compounds.
[68] Other suitable compounds B) are the reaction products of hydroxyl group-bearing monoepoxides with the above-mentioned , -Ethylenically unsaturated mono- and dicarboxylic acids. The reaction product of glycidol (2,3-epoxy-1-propanol) with acrylic acid or methacrylic acid is preferred.
[69] Another suitable compound B) is the reaction product of the α, β-ethylenically unsaturated mono- and dicarboxylic acids with an epoxide having the formula: embedded image which contains two terminal epoxide groups:
[70]
[71] In this formula,
[72] A is -O-;
[73] A radical of the formula -O- (CH ₂ CH ₂ O) _p (CH ₂ CH (CH ₃ ) O) _q - in which any desired order of ethylene oxide units may be present and p and q Is an integer from 1 to 20, preferably from 0 to 10, and the sum of p and q is greater than 0;
[74] A radical of the formula -O- (CH ₂ ) r O-, wherein r is an integer from 1 to 10, preferably from 1 to 7; or
[75] Wherein R ¹ , R ² and R ³ , which are independent of ^{one another} , are each hydrogen C ₁ to C ₈ -alkyl or C ₅ to C ₇ cycloalkyl,
[76]
[77] Such suitable epoxides having two terminal epoxide groups are described in DE-A 21 64 386 and US-A 3,373,075, the disclosures of which are incorporated herein by reference in their entirety.
[78] Suitable compounds B) are esters of the above-mentioned , - ethylenically unsaturated mono- and / or dicarboxylic acids with trihydric and polyhydric alcohols, and only some of the hydroxyl groups are esterified, Or more of the free hydroxyl groups.
[79] Suitable trihydric and polyhydric alcohols are the triols and polyols described below as component E). Preferred partial esters B) are, for example, trimethylolpropane mono (meth) acrylate, erythritol mono- and di (meth) acrylate, pentaerythritol mono- and di to be.
[80] Preferred compounds B) are the reaction products of 2,3-epoxy-1-propanol or bisphenol A diglycidyl ether with acrylic acid and / or methacrylic acid. Bisphenol A diglycidyl ether is commercially available, for example, from Epikote 828 828, manufactured by Shell).
[81] Suitable compounds C) are esters of the above-mentioned , - ethylenically unsaturated mono- and dicarboxylic acids, preferably acrylic acid and methacrylic acid, with C ₂ to C ₂₀ diols, preferably C ₂ to C ₁₀ diols . These may be, for example, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3- Hydroxypropylmethacrylate, 3-hydroxybutyl acrylate, 3-hydroxybutyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 6-hydroxybutyl methacrylate -Hydroxyhexyl acrylate, 6-hydroxyhexyl methacrylate, 3-hydroxy-2-ethylhexyl acrylate, 3-hydroxy-2-ethylhexyl methacrylate, and the like, and mixtures thereof.
[82] Suitable compounds C) are esters of the above alpha, beta -ethylenically unsaturated mono- and / or dicarboxylic acids with trihydric and polyhydric alcohols. By a suitable reaction procedure, only a portion of the hydroxyl groups of the alcohol component are esterified, and the resulting ester has one free hydroxyl group per molecule. Suitable alcohols for the preparation of these esters C) are the triols and polyols mentioned below as component E). Preferred component C) is, for example, erythritol tri (meth) acrylate, pentaerythrityl tri (meth) acrylate and mixtures thereof.
[83] The component C) can be used individually or in the form of a mixture.
[84] Suitable polymers D) are, for example, polyols having a molecular weight of from about 400 to 5000, preferably from about 700 to 2500. Known polyester polyols, polyetherols, polycarbonate diols and polycaprolactone diols are suitable for this use.
[85] Suitable polyesterols D) are, for convenience, primarily linear polymers with terminal OH groups, preferably those with two terminal OH groups. The acid value of the polyesterol is generally less than 10, preferably less than 3. The polyesterol can be obtained by esterification of an aliphatic, alicyclic or aromatic dicarboxylic acid having 4 to 15 carbon atoms, preferably 4 to 6 carbon atoms, with a glycol, preferably a glycol having 3 to 20 carbon atoms, ≪ / RTI > Examples of suitable dicarboxylic acids are malonic acid, glutaric acid, pimelic acid, suberic acid, sebacic acid, dodecanedioic acid, diphenic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, preferably adipic acid , Succinic acid and phthalic acid. The dicarboxylic acids may be used individually or in the form of mixtures. In the preparation of the polyesterol, it may be advantageous to use the corresponding acid derivatives and carboxylic acid anhydrides or carbonyl chlorides instead of dicarboxylic acids. Mixtures of aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, diphenic acid, or mixtures thereof with other dicarboxylic acids such as sebacic acid, succinic acid, and adipic acid are also suitable.
[86] Examples of suitable glycols are diethylene glycol, 1,5-pentanediol, 1,10-decanediol and 2,2,4-trimethyl-1,5-pentanediol. 1,2-ethanediol, 1,4-butanediol, 1,6-hexanediol and 2,2-dimethyl-1,3-propanediol; 1,4-dimethylolcyclohexane, 1,6-dimethylcyclohexane and 1,4-diethanolcyclohexane; And ethoxylated / propoxylated products of 2,2-bis (4-hydroxyphenylene) propane (bisphenol A) are preferably used. Depending on the desired properties of the polyurethane acrylates, the polyols may be used alone or in the form of a mixture of various ratios. Suitable lactones for the production of polyestherols are, for example, , -Dimethyl- -Propiolactone, -Butyrolactone, preferably -Caprolactam.
[87] Suitable polyetherols D) are essentially linear materials with terminal hydroxyl groups, contain ether linkages and have molecular weights of from about 400 to 5000, preferably from 700 to 2500. Suitable polyetherols can be prepared by polymerizing a cyclic ether such as tetrahydrofuran or by reacting at least one alkylene oxide having 2 to 4 carbon atoms in the alkylene radical with two active hydrogen atoms ≪ / RTI > with an initiator molecule containing an initiator. Examples of alkylene oxides include ethylene oxide, 1,2-propylene oxide, epichlorohydrin and 1,2- and 2,3-butylene oxide. The alkylene oxides may be used individually or alternatively may be used continuously or in the form of a mixture. Examples of suitable initiator molecules include water, ethylene glycol, propylene glycol, glycols such as 1,4-butanediol, 1,6-hexanediol and bisphenol A, ethylenediamine, hexamethylenediamine, and 4,4'-diaminodiphenylmethane , And amino alcohols such as ethanolamine. As in the case of polyestherols, polyetherols may be used alone or in the form of mixtures.
[88] Suitable polycarbonate diols D) as well as their preparation are described in US-A 4,131,731 and are generally based on hexane-1,6-diol.
[89] Suitable polymers D) are also polydiol and polyols having a molecular weight of about 5000 to 30,000. The alcohol content of these polymers is generally from about 2 to about 15, preferably from 3 to 10, per molecule. Known polyesterols, polyetherols, hydroxyl-containing polycarbonates and hydroxyl-containing polycaprolactams are also suitable for this application.
[90] Preferred polyesterols are, for example, polycondensates of dibasic and / or polybasic aliphatic, cycloaliphatic and / or aromatic carboxylic acids. Suitable alicyclic dicarboxylic acids are, for example, 1,2-, 1,3- or 1,4-cyclohexanedicarboxylic acids. Suitable aliphatic dicarboxylic acids are, for example, malonic acid, succinic acid, adipic acid, and the like. Suitable aromatic carboxylic acids are, for example, terephthalic acid, isophthalic acid, phthalic acid, trimellitic acid and the like. Suitable alcohol components are generally the abovementioned diols, triols, and polyols such as polyesterols, polyetherols and the like. It is preferable to use aliphatic diols such as ethylene glycol, propylene glycol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, polyethylene glycol, polypropylene glycol and 1,4-dimethylcyclohexane. Suitable polyesterols D) are commercially available, for example, from Desmophen, such as Desmophen 1000, 2000, and 2020 from Bayer AG, ), Or as Dynapol L206 from Huels Troisdorf AG of the Fels, Dynapol < RTI ID = 0.0 > ).
[91] Suitable hydroxyl-containing polyethers and polylactones D) are commercially available, for example, from UCC, Niax )to be.
[92] The polymer D) described above can be used individually or in the form of a mixture.
[93] The polyurethane acrylate a) can be prepared by reacting a diol, a compound having two or more primary and / or secondary amino groups per molecule, an amino alcohol, a triol, a polyol, Water, and mixtures thereof, as component E).
[94] Suitable amines E) are aliphatic and cycloaliphatic amines having two or more primary and / or secondary amino groups per molecule, linear and branched, generally having from about 1 to 30, preferably from 1 to 20 carbon atoms They are. These are, for example, ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6- 7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 4 , 9-dioxododecane-1,12-diamine, 4,4'-diaminodiphenylmethane, 4-aminopiperidine and derivatives thereof such as 4-amino-2,6-dimethylpiperidine Amino-2,6-diisopropylpiperidine, 1-amino-2,6-di-n-propylpiperidine, (2-aminoethyl) piperazine, 4,4-diaminodicyclohexylmethane, 4,4'-diaminodiphenylmethane, diethylenetriamine, dipropylenetriamine, triethylenetetramine, 4- Methylenediamine and N, N'-bis (3-aminopropyl) butane-1,4-diamine and mixtures thereof.
[95] Diols having 2 to 18, preferably 2 to 10 carbon atoms and alkoxides of these having low alkoxylation can also be used as component E), for example 1,2-ethanediol, 1,3- Propanediol, 1,4-butanediol, 1,6-hexanediol, 1,5-pentanediol, 1,10-decanediol, 2-methyl- Propane diol, 2,2-dimethyl-1,3-propanediol, 2,2-dimethyl-1,4-butanediol, Diethylene glycol, triethylene glycol, bisphenol A, and the like. The diols may be used individually or in the form of mixtures. The diol and diamine E) can be partly replaced with up to 20% by weight, preferably up to 10% by weight, based on the total amount of E).
[96] Other suitable components E) are amino alcohols having from 2 to 16, preferably from 3 to 8, carbon atoms, for example monoethanolamine, methylisopropanolamine, ethylisopropanolamine, methylethanolamine, 3-aminopropanol, 1-ethylaminobutan-2-ol, 4-methyl-4-aminopentan-2-ol and N- (2-hydroxyethyl) aniline. It is preferable to use a secondary amino alcohol.
[97] Suitable triols E) are compounds having from 3 to 25, preferably from 3 to 18, particularly preferably from 3 to 6 carbon atoms. An example of a triol that can be used is glycerol or trimethylolpropane. The reaction products of low molecular weight reaction products of triols and polyols, such as trimethylol propane, with alkylene oxides such as ethylene oxide and / or propylene oxide, are also suitable. The polyols used may be, for example, erythritol, pentaerythritol and sorbitol. The presence of triols and / or polyols during the polycondensation results in the branching of the final product, which generally has a beneficial effect on the mechanical properties of the polyurethane when local crosslinking does not occur.
[98] According to one preferred embodiment, the polyurethane acrylate a) consists of the following components:
[99] - 1.0 to 10 mol, preferably 1.4 to 8 mol of one or more compounds A),
[100] - from 0 to 6 moles, preferably from 0.1 to 5 moles of at least one compound B),
[101] - 0.1 to 6 mol, preferably 0.2 to 5 mol, of at least one compound C),
[102] - 0.1 mol of at least one component D), and
[103] - from 0 to 9.0 mol, preferably from 0.1 to 4 mol, of at least one component E).
[104] Polyurethane acrylates a) are prepared by conventional methods known to those skilled in the art. The components are such that the equivalent ratio of the NCO equivalents of the component A) compound to the active hydrogen atoms of the components B), C), D), and E) (if present) is from about 0.8: 1 to 1.2: 1, To 1.1: 1. The temperature is generally about 20 to 90 占 폚, preferably 30 to 70 占 폚. The reaction can be carried out without solvent or in a suitable inert solvent or solvent mixture. Halogenated hydrocarbons such as chloroform, tetrachloromethane, and 1,2-dichloroethane, ketones such as acetone and methyl ethyl ketone, esters such as ethyl acetate, nitriles such as acetonitrile, N Methylpyrrolidone, dimethylformamide, dimethylsulfoxide, tetrahydrofuran, dioxane and the like are preferably used. If necessary, the reaction can be carried out under an inert gas atmosphere, for example, a nitrogen atmosphere. The resulting polyurethanes generally no longer have free isocyanate groups.
[105] Suitable catalysts for the preparation of polyurethane acrylates are, for example, tertiary amines such as triethylamine, triethylenediamine, N-methylpyridine and N-methylmorpholine; Tin octanoate (II), lead octanoate and metal salts such as zinc stearate, and organometallic compounds such as dibutyltin dilaurate. The suitable amount of catalyst depends on the efficiency of the suitable catalyst. Generally, it has proven convenient to use from 0.005 to 0.3 parts by weight, preferably from 0.01 to 0.1 part by weight, per 100 parts by weight of polyurethane.
[106] The preparation of polyurethane acrylate a) can in principle be carried out by a one-step process or a two-step process. In the one-step process, the starting components are generally dissolved in a portion of the solvent to form a solution having a solids content of about 30 to 80 wt%. The solution is then heated with stirring to the above reaction temperature. The components are reacted until the content of isocyanate groups is substantially zero. The solution can then be diluted to a concentration suitable for further processing, if desired. Any isocyanate preexisting monomers still present can be finally reacted with a terminalizing agent such as a monoalcohol or monoamine. In the two-step process, the isocyanate component A) is first taken up in some solvent, if necessary, and heated to the reaction temperature. The components B), C) and, if necessary, D), the catalyst and, if necessary, auxiliaries and additives, if necessary, are also added, in some solvents, to the isocyanate component A) at least once while maintaining the reaction. After the addition is complete, the reaction is continued until the isocyanate group content in the mixture is substantially constant. Then, component C) is added in the second step.
[107] The resulting polyurethane acrylate a) preferably has a K value of about 20 to 80, preferably 25 to 60 (measured according to H. Fikentscher, Cellulosechemie 30 (1931), 58 et seq.) .
[108] Component b)
[109] Suitable components b) with three UV-curable alpha, beta -ethylenically unsaturated double bonds per molecule are, for example, triols described as component E) above and their alkoxides and the , ethylenically unsaturated mono- and dicarboxylic acids, preferably acrylic acid and methacrylic acid. These include, for example, propanetriol triacrylate, trimethylolpropane triacrylate, propanetriol trimethacrylate, trimethylolpropane trimethacrylate and the like and alkoxides thereof.
[110] Further suitable compounds b) are the polyester esters obtained from the , - ethylenically unsaturated monocarboxylic acids with polyesterols having three hydroxyl groups. Processes for preparing polyester acrylates having three hydroxyl groups are known. They generally contain, as polymerized units, the above-mentioned aliphatic and / or cycloaliphatic diols mixed with an appropriate amount of triols and saturated dicarboxylic acids as described above.
[111] Other suitable compounds b) are urethane isocyanurate having three , - ethylenically unsaturated double bonds. These include, for example, the reaction product of an isocyanate prepolymer having triisocyanate or three isocyanate groups with the hydroxyalkyl (meth) acrylate described above as component C). If necessary, the triisocyanate or isocyanate prepolymer is first reacted with at least one chain extender selected from diols, diamines and amino alcohols described above as component E), and then the , - ethylenically unsaturated mono- or dicarboxylic It may be reacted with an acid.
[112] An additional suitable component b) is an epoxide acrylate based on triglycidyl ether. Suitable triglycidyl ethers can be prepared, for example, by reacting alcohols and their alkoxides with epichlorohydrin, the triols described above as component E) above and the trihydrogenated ones. The reaction of the alcohol, which is more polyhydric than trihydrogenated, with epichlorohydrin can be carried out at a suitable molar ratio such that the triglycidyl ether is produced substantially. Triglycidyl ether can be reacted with the above-mentioned , - ethylenically unsaturated mono- and / or dicarboxylic acid to obtain epoxide acrylate b). Suitable triglycidyl ethers for the preparation of these compounds b) are, for example, trimethylolpropane triglycidyl ether, erythrityl triglycidyl ether, pentaerythrityl ether and the like.
[113] Component c)
[114] Suitable components c) having two UV-curable alpha, beta -ethylenically unsaturated double bonds per molecule are the diols, polyether diols, polyester diols and polycarbonate diols and their alkoxides and the < RTI ID = Ethylenically unsaturated mono- and dicarboxylic acids. These include, for example, ethanediol diacrylate, ethanediol dimethacrylate, propanediol diacrylate, pentanediol dimethacrylate, butanediol diacrylate, butanediol dimethacrylate, pentanediol diacrylate, hexanediol (Meth) acrylate, neopentyl glycol dimethacrylate, neopentyl glycol dimethacrylate, triethylene glycol (meth) acrylate, hexanediol di (meth) acrylate, Diacrylate, triethylene glycol dimethacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, tripropylene glycol diacrylate, tripropylene glycol dimethacrylate, cyclohexanediol diacrylate, cyclo Hexanediol dimethacrylate, alkoxylated Diacrylates and dimethacrylates of bisphenol A, hydrogenated bisphenol A and the like, and diacrylates and dimethacrylates of alkoxides thereof.
[115] Further suitable compounds c) are the reaction products described above as component B) and obtained from glycidyl ethers and , - ethylenically unsaturated monocarboxylic acids. It is preferred to use bisphenol A diglycidyl ether diacrylate and dimethacrylate (diacrylate and dimethacrylate of Episcote 828, Shells). The diglycidyl ether may be reacted with at least one saturated dicarboxylic acid, if necessary, before the reaction with the unsaturated carboxylic acid, and the molar ratio of diglycidyl ether to dicarboxylic acid is essentially two terminal epoxide groups The product is selected to be obtained. Diglycidyl ether di (meth) acrylate having a higher molecular weight and higher alcohol value than that obtained by pre-reacting diglycidyl ether with a saturated dicarboxylic acid is obtained.
[116] Suitable compounds d) are, for example, N-vinyl amides of carboxylic acids, sulfonic acids and phosphonic acids. These include, for example, N-vinyl formamide, N-vinylacetamide, N-vinyl propionamide and the like. N-vinylformamide is preferably used.
[117] Suitable monomers d) are also N-vinyllactams and their derivatives, which may include, for example, one or more Cs such as methyl, ethyl, n-propyl, isopropyl, n-butyl, _And may have ₁ to ₆ alkyl substituents. These include, for example, N-vinylpyrrolidone, N-vinylpiperidone, N-vinylcaprolactam, N-vinylmorpholine, N-vinylpiperazine, N-vinyl- Ethyl-2-pyrrolidone, N-vinyl-6-methyl-2-piperidone, N-vinyl- Caprolactam, N-vinyl-7-ethyl-2-caprolactam, N-vinyl-4-ethylpiperazine and the like.
[118] Suitable monomers d) are also vinyl- and allyl-substituted heteroaromatic compounds such as 2- and 4-vinylpyridines and 2- and 4-allylpyridines, preferably N-vinyl heteroaromatics, for example N-vinylimidazole and N-vinyl-2-methylimidazole.
[119] The novel binder composition may additionally contain as component e) at least one ester of an alpha, beta -ethylenically unsaturated monocarboxylic acid and an aliphatic or cycloaliphatic C ₁ to C ₂₀ monoalcohol. The amount of this component is generally about 0 to 30 mol% based on the total amount of components a) to e).
[120] Suitable monomers e) are selected from the group consisting of acrylic acid and / or methacrylic acid and at least one monomer selected from the group consisting of methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, Ethylhexanol, dodecanol, hexadecanol, octadecanol, cyclohexanol, and the like.
[121] By using the monofunctional monomers d) and / or e), the reticulate density of the new binder composition can vary within a wide range. In general, the amount of monomers d) and / or e) is not more than 40 mol%, preferably not more than 30 mol%, based on the total amount of components a) to e). By using the monomers of component d) it is generally possible to reduce the viscosity of the binder composition prior to curing, which generally has a beneficial effect on flow and processability. Also, in the presence of monomer d), acceleration of the curing rate and / or complete curing of the binder composition is generally observed. In addition, the resistance of the binder composition to oxygen and oxidizing agents can generally be improved by using monomer d). Advantageously, rapid surface hardening of the binder composition is generally observed in the use of monomer d). The use of monofunctional monomer e) generally results in a binder layer with improved extensibility and / or adhesion.
[122] The new UV-curable binder compositions described above can be used, if desired, in the manufacture of customary eye-free coatings. These coatings generally contain one or more conventional photoinitiators. Suitable photoinitiators are those described below, and generally there is no need to use any specific mixture to cure the unpainted coating. Preferably, a new binder composition is used in the preparation of the pigment-containing coating material as described below.
[123] The present invention also relates to UV-curable coatings comprising the following components:
[124] I) one or more new binder compositions as described above,
[125] Ii) at least one photoinitiator,
[126] Iii) one or more pigments selected from carbon black, non-magnetic and abbreviated metal oxides and mixtures thereof, and mixtures comprising carbon black and one or more magnetic pigments,
[127] Iv) at least one polyurethane (meth) acrylate having a dispersing active group, and
[128] V) optionally, one or more polyesters.
[129] Component i)
[130] Preferably, the novel coating comprises from 50 to 95.99% by weight, preferably from 60 to 90% by weight, based on the total amount of components i) to v) of the one or more binder compositions.
[131] Component ii)
[132] The new coating contains a photoinitiator mixture comprising at least one -Cutter, at least one H-extractant and at least one acylphosphine oxide or sulfide as component ii). It is preferred that the photoinitiator mixture comprises 75-98 wt% of the alpha -cutter, 1 to 24 wt% of the H-extractant, and 1 to 24 wt% of the acylphosphine oxide or sulfide.
[133] The new coating contains from 0.01 to 10% by weight, preferably from 0.1 to 9.0% by weight, in particular from 0.2 to 8% by weight, of the photoinitiator mixture, based on the total amount of components i) to v).
[134] [alpha] -cutting agents are generally defined as photoinitiators which, after irradiation and absorption, form free radicals by decomposition by intramolecular bond cleavage of excited initiators. Suitable .alpha.-cleaving agents for the photoinitiator mixtures used according to the invention are benzoin, benzoin ethers, preferably benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether, alpha-alkyl benzoin ether, benzyl ketal For example, benzyl dimethyl ketal and benzyl diethyl ketal, alpha -acyl oxime ester, acetophenone, dialkoxyacetophenone, such as dimethoxyacetophenone, diethoxyacetophenone and di-n-propoxyacetophenone, Hydroxy-isobutyrophenone, p-tert-butyl-a-hydroxyisobutyrophenone, p-octyl- -hydroxyisobutyrophenone, p-dodecyl- -hydroxyisobutyrophenone, p-chloro- -hydroxyisobutyrophenone, p-bromo- -hydroxyisobutyrophenone, p-methoxy - - hydroxyisobutyrophenone, p-ethoxy- -hydroxyisobutene Thiophenone, 3,4-dimethyl- -Hydroxyisobutyrophenone, 3,4-dimethoxy- -Hydroxyisobutyrophenone, 3-chloro- -Hydroxyisobutyrophenone, -Hydro Hydroxybenzyl cyclopentanol, 1-benzoyl cyclohexanol, 1- (4-chlorobenzoyl) cyclohexanol, hydroxycyclo- [alpha] Alkylphenones such as hydroxycyclohexylphenone, heterocycloalkylphenones, and mixtures thereof. Preferred are heterocycloalkylphenones of the formula (I)
[135]
[136] In this formula,
[137] R ¹ and R ² are each independently of the other hydrogen, C ₁ -C ₂₀ alkyl, C ₁ -C ₂₀ alkoxy, C ₁ -C ₂₀ alkylthio, phenyl, phenoxy, phenylthio or halogen,
[138] R ³ and R ⁴ are, independently of each other, C ₁ -C ₆ alkyl, phenyl-C ₁ -C ₆ -alkyl or cycloalkyl,
[139] X is CH ₂ , O, S or NR ⁵ wherein R ⁵ is hydrogen, C ₁ -C ₆ alkyl or cyclohexyl.
[140] R ¹ is preferably C ₁ to C ₂₀ alkylthio, especially methylthio.
[141] R ² is preferably hydrogen.
[142] R < ³ > and R < ⁴ > are each independently of the other preferably C ₁ to C ₆ alkyl and especially both are methyl.
[143] X is preferably O or CH ₂ .
[144] A particularly preferred α-cleaving agent is 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one.
[145] The H-extractant is very generally defined as a photoinitiator that forms free radicals by intermolecular hydrogen transfer from an assistant initiator to an excited initiator molecule after activation by the light-absorbing agent. Suitable co-initiators are, for example, alcohols and primary or secondary amines. In the case of the photoinitiator mixtures used according to the invention, it is generally possible to avoid the addition of auxiliary initiators, since the new binder compositions have sufficient hydroxyl and / or amino groups. Suitable H-extracting agents include benzophenone, benzophenone derivatives such as alkylbenzophenones such as 4-methylbenzophenone, 4-ethylbenzophenone, 2,4-dimethylbenzophenone and 4-isopropylbenzophenone, 2- Halogenated benzophenones such as chlorobenzophenone and 2,2'-dichlorobenzophenone, alkoxybenzoates such as 2-methoxybenzophenone, 4-methoxybenzophenone, 4-propoxybenzophenone and 4-butoxybenzophenone Benzene, Michler's ketone, anthraquinone, anthraquinone derivatives such as 2-methyl anthraquinone, 2-ethyl anthraquinone, 2-n-propylanthraquinone and 2-n- Such as 2-alkylanthraquinone, thioxanthone, thioxanthone derivatives such as 1- and 2-methylthioxanthone, 1- and 2-ethylthioxanthone, 1- and 2-n-propylthioxanthone And 1- and 2-alkylthioxanthones, such as 1- and 2-isopropylthioxanthone, and isomeric mixtures thereof, and 1- and 2- 2-chlorothioxanthone.
[146] Preferred H-extracting agents are selected from thioxanthone and thioxanthone derivatives. For example, Shell Chemie's Quantacure ITX (Quantacure < RTI ID = 0.0 > ITX) can be preferably used.
[147] Compounds having both the typical structural elements in the alpha -cutting agent and the typical structural elements in the H-extractant are also suitable for use in the photoinitiator mixtures. Such suitable thioxanthone derivatives are described in DE-A 38 26 947, which is incorporated herein by reference in its entirety. These compounds may be used alone in combination with acylphosphine oxide or sulfide, or optionally in combination with one or more additional a-cleavage agents and / or one or more additional H-extraction agents.
[148] Suitable photoinitiators as acylphosphine oxide or sulfide components are described in DE-A 40 25 386, DE-A 42 31 579, DE-A 42 40 964, EP-A 0 184 EP-A 0 413 654, EP-A 0 446 175, EP-A 0 495 751, EP-A 0 495 752, EP-A 0 513 534 and EP-A 0 615 980 Lt; / RTI > Pivaloyldiphenylphosphine oxide and sulfide, p-tert-butylbenzoyldiphenylsulfone, p-tert-butylphenylphosphine oxide and sulfide, p-tert-butylbenzoyldiphenyl Phosphine oxide and sulfide, -Naphthoyldiphenylphosphine oxide and sulfide, 2,6-dimethylbenzoyldiphenylphosphine oxide and sulfide, 2,6-dimethoxybenzoyldiphenylphosphine oxide and sulfide, 2,4 , 6-trimethylbenzoyldiphenylphosphine oxide and sulfide, 2,6-dichlorobenzoyldiphenylphosphine oxide and sulfide, 1,3-dimethyl-2-naphthoyldiphenylphosphine oxide and sulfide, 1,3-dichloro -2-naphthoyldiphenylphosphine oxide and sulfide, 2,4-dimethylfuran-3-carbonyldiphenylphosphine oxide and sulfide, 2,4,6-trimethylpyridine-3-carbonyldiphenylphosphine oxide And sulfide, 2,6-dimethoxybenzoyldiphenylphosphine oxide and sulfide, 2,6-dichlorobenzoyldithylphosphine oxide and sulfide, methylpivaloylphenylphosphinate and -sulfinate, methyl 2,4- Bis (2,6-dichlorobenzoyl) phenylphosphine oxide and sulfide, bis (2,6-dichlorobenzoyl) -4-chlorophenylphosphine oxide and sulfide, bis (2,6-dichlorobenzoyl) -1-naphthylphosphine oxide and sulfide, bis (2,6-dichlorobenzoyl) -4-tert- butylphenylphosphine oxide and sulfide, bis (2,6-dimethylbenzoyl) -4-tolylphosphine oxide and bis (2,6-dimethylbenzoyl) -1-naphthylphosphine oxide and sulfide, bis Sulfide, bis (2,6-dimethoxybenzoyl) phenylphosphine oxide and sulfite Bis (2,6-dimethoxybenzoyl) -2-naphthylphosphine oxide and sulfide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide and sulfide, bis (2,4,6-trimethylbenzoyl) ) -4-methoxyphenylphosphine oxide and sulfide, bis (2-methyl-1-naphthoyl) phenylphosphine oxide and sulfide, bis (2,6-dichlorobenzoyl) , And mixtures thereof, are used.
[149] The photoinitiator mixtures used are, in particular, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one (Ciba Spezialitaeten- Cure 907 (Irgacure 907), isopropyl thioxanthone (Quantacure ITX from Shell Chemie) and 2,4,6-dimethylbenzoyldiphenylphosphine oxide (Lucirin (BASF AG, BASF AG) TPO), 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide (lucyline LR8893 from BASF Aktiengesellschaft) and / or bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide Chi alithetense).
[150] The present invention also relates to the use of said photoinitiator mixtures comprising at least one -Cutter, at least one H-extractant and at least one acylphosphine oxide or sulphide in the curing of the carbon black-containing coating material by UV irradiation . Advantageously, a sufficiently high curing rate is obtained when such a photoinitiator mixture is used, making it possible to use the coating material in the manufacture of magnetic tapes, which typically have a high throughput rate which is usually conventional. Therefore, it is generally not possible to use a technically complex and expensive apparatus for curing the carbon black-containing coating material by the electron beam.
[151] The present invention also relates to novel photoinitiator mixtures containing the following components:
[152] One or more acylphosphine oxides or sulfides as defined above,
[153] At least one -Cutter, as defined above, and
[154] At least one H-extractant selected from benzyl, microclerketone, anthraquinone, anthraquinone derivatives, thioxanthone, thioxanthone derivatives and mixtures thereof.
[155] Suitable anthraquinone and thioxanthone derivatives are those described above. These photoinitiator mixtures are preferably suitable for curing pigments containing, especially carbon black containing coatings.
[156] Component iii)
[157] All known carbon black or carbon black compounds with electrical conductivity are suitable for new, UV-curable coatings. Preferably, the average particle size of the carbon black is about 5 to 500 mu m, preferably about 10 to 300 mu m. When a new carbon black-containing coating material is used as the priming layer of the magnetic recording medium, it is generally possible to avoid the accumulation of electrostatic charges and related problems, such as adhesion of the tape.
[158] Suitable non-magnetic pigments are, for example, alumina, silica, titanium dioxide, chromium trioxide and zirconium oxide.
[159] Suitable abbreviated pigments are those conventional to those skilled in the art.
[160] Of the pigments described above, pigments containing carbon black and carbon black are preferred.
[161] Other suitable components iii) are pigment mixtures comprising carbon black and one or more magnetic pigments customary in the production of magnetic tapes described below.
[162] Preferably, the new coating contains component iii) in an amount of from 2 to 40% by weight, preferably from 10 to 30% by weight, based on the total amount of coating materials i) to v).
[163] Component iv)
[164] The new UV-curable coating may contain one or more dispersing resins, if desired. It is used in an amount of about 0.01 to 50% by weight, preferably 1 to 25% by weight, based on the total amount of components i) to v). Suitable polyurethane dispersion resins are described in documents cited therein, for example DE-A 41 41 838, DE-A 44 46 383 and DE-A 195 16 784, the entireties of which are hereby incorporated by reference.
[165] Polyurethane (meth) acrylates and / or polyurea (meth) acrylates suitable for dispersion resins are obtainable by the following method:
[166] Ⅰ) a) α, β- unsaturated mono- 80 to 100 mol% and / or dicarboxylic acid with C ₁ to C ₂₅ ester of one or more alkanolamines,
[167] b) from 0 to 20 mol% of one or more further monomers and
[168] c) a hydroxyl-containing polymer P1) comprising at least one initiator and / or modifier, wherein most of the polymer P1) has a hydroxyl group end at one of its chain ends,
[169] II) reacting with a diisocyanate or polyfunctional isocyanate to obtain polymer P2) wherein the amount of isocyanate groups is 1.2 to 3.9 moles per mole of hydroxyl groups in P1)
[170] III.) P2) with ammonia, or with at least one compound having an amino group that is reactive toward isocyanate groups,
[171] III.2) reacting P2) with a compound containing a group reactive with isocyanate group to obtain polymer P3) and subsequently reacting P3) with an acid group into polymer P3)
[172] III.3) P2) is reacted with at least one compound having a group reactive with the isocyanate group and introducing an acid group into the polymer P).
[173] Component v)
[174] The new coating contains at least one hydroxyl-containing polymer, if desired. It is used in an amount of about 0.01 to 50% by weight, preferably about 1 to 45% by weight, based on the total amount of components i) to v). Preferably, they are polymers having no , -Ethylenically unsaturated double bonds. Polydiol and polyol having a molecular weight of about 5000 to 30,000 as described above as component D) are suitable. These include, among others, the product Dyspol, especially DynaPol L206 from Desmophen, Union Carbide, Bayer, and Niels and Fries Trous Aktiengesellschaft.
[175] The new UV-curable coatings may contain further additives if desired. These include, for example, conventional flow improvers and / or glidants. If desired, the new coating may contain one or more inert diluents. Suitable diluents include, for example, aprotic polar solvents such as dimethylformamide and dimethylacetamide, dialkylformamides such as dimethylsulfoxide, cyclic ethers such as tetrahydrofuran and dioxane, N-methyl N-alkylpyrrolidone such as pyrrolidone, ketones such as acetone and methyl ethyl ketone, and the like. Also suitable are mixtures of alkanes, cycloalkanes and aromatics and solvents.
[176] Suitable lubricants are, for example, carboxylic acids of from 10 to 25 carbon atoms, in particular stearic acid or palmitic acid, and their salts, esters and / or amides. Preferably, a novel pigment-containing coating material for the production of magnetic recording media is formulated into a cast composition. The casting mixture can be prepared by conventional methods. The carbon black-containing dispersion may be prepared by adding one of the above-mentioned solvents from the components i) to iii) and, if necessary, iv) and / or v) in a dispersing device such as a tubular ball mill or a stirring ball mill, . If necessary, the casting mixture may be filtered, for example, in a conventional manner prior to application to separate and remove the agglomerates.
[177] The present invention also provides a magnetic recording medium comprising a nonmagnetic substrate and at least one magnetic recording layer, wherein the magnetic recording layer contains finely divided ferromagnetic powder dispersed in a binder and is applied over the priming layer on the substrate, The layer is derived from one or more UV cured coatings as described above.
[178] The new magnetic recording media are manufactured by the known methods themselves.
[179] Suitable non-magnetic and non-magnetizable substrate materials are conventional rigid or flexible substrate materials, in particular linear polyester films, such as polyethylene terephthalate, generally 2 to 200 μm, in particular 3 to 100 μm thick. It is also possible to use a magnetic layer on a paper substrate.
[180] According to a preferred embodiment, a cast composition of a new carbon black containing UV-curable coating is first applied to a substrate. The coating rate is about 1 to 800 m / min, preferably about 5 to 300 m / min.
[181] Mold casting apparatus suitable for applying the casting composition to a movably mounted substrate are, for example, a kiss coater, a bar coater, a blade coater, a knife coater, a roll coater or a reverse-roll coater. After the casting composition is applied to the substrate, curing is carried out by UV light, and the mixture is dried in advance or simultaneously at an elevated temperature, if necessary. UV curing is carried out by moving the coated substrate through an actinic light source having a wavelength of about 200 to 750 nm, preferably 200 to 400 nm, in a device common to such applications. Suitable UV irradiators or UV lamps are, for example, mercury vapor lamps, high pressure mercury vapor lamps, excimer lamps, flash lamps, tungsten halide lamps, hollow cathode lamps, helium discharge lamps, excimer lasers,
[182] When the coating is dried before UV curing or during curing, the temperature is generally about 60 to 120 캜, preferably 70 to 110 캜. The new carbon black containing coatings are advantageously suitable for coating the backside of the substrate material, which in particular improves the mechanical properties of the magnetic recording medium and serves to reduce the build up of electrostatic charge during unwinding and rewinding. If desired, two or more priming layers may be applied to one or more sides of the substrate material. When the substrate is coated on both sides and / or when two or more priming layers are applied to more than one side of the substrate, this can be done at the same time or at different times, if necessary after drying or curing of the first priming layer. If desired, the layers may be applied wet-in-wet to the substrate in one application step, and may be dried and / or cured together, if desired. Suitable methods of simultaneously applying multiple layers are known to those skilled in the art. These include, in particular, blade coating, bar coating, extrusion coating or knife coating methods and cascade coating methods. The front and back sides of the substrate are generally coated at different times.
[183] Optionally, prior to application of the magnetic layer, the priming layer may be calendered and compressed by passing between heated and polished rolls at elevated temperatures on a conventional calendering device and pressing as necessary. The temperature during calendering is about 60 to 120 캜, preferably about 70 to 110 캜, as in the case of drying. The thickness of the carbon black-containing priming layer is generally about 0.05 to 5 mu m, preferably 0.3 to 3 mu m.
[184] The new carbon black-containing coatings containing the photoinitiator mixture as described above advantageously have a high cure rate and can be reliably cured even at high belt speeds typical of magnetic tape manufacturing. UV cured films are generally dust-free and solvent resistant. The new binder compositions used in the coatings advantageously allow complete dispersion of the carbon black and, if desired, further customary additives, so that generally no coagulation or spotting occurs.
[185] Conventional magnetic pigment dispersions are used to apply the magnetic layer. The dispersion generally contains a magnetic pigment dispersed in a binder or a mixture of binders and optionally contains further conventional additives and auxiliaries such as solvents or diluents, dispersing resins, fillers, lubricants, flow improvers and the like .
[186] Suitable binders for magnetic materials are, for example, polymers containing at least one free radically polymerizable alpha, beta -ethylenically unsaturated monomer as polymerized units. Suitable monomers include C ₂ to C ₈ monoolefins such as ethylene, propylene, 1-butene and 2-butene, vinyl aromatic compounds such as styrene, a-methylstyrene, o-chlorostyrene and vinyltoluene, Vinylidene halides such as vinyl fluoride, vinylidene fluoride, vinyl chloride and vinylidene chloride, esters of vinyl alcohol with C ₁ to C ₂₀ monocarboxylic acids such as vinyl formate, vinyl acetate, vinyl propionate Monoethylenically unsaturated mono- and dicarboxylic acids and C ₁ to C ₂₀ alkanols, preferably C ₁ to C ₈ alkanols, preferably C ₁ to C ₈ alkanols, Esters of acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid and crotonic acid with methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutane And esters with 2-ethylhexanol, dimethyl maleate and n-butyl maleate, [alpha], [beta] -ethylenically unsaturated nitriles such as acrylonitrile and methacrylonitrile, amides of acrylic acid and methacrylic acid, Aromatic hydrocarbons having 8 carbon atoms and 2 or more olefinic double bonds such as butadiene, isoprene and chloroprene, and mixtures of these monomers.
[187] Suitable binders for magnetic materials are also cellulose derivatives, such as cellulose esters, preferably cellulose nitrate, cellulose acetate, cellulose acetopropionate and cellulose acetobutyrate, and epoxy resins, preferably with, for example, bisphenol A Is a phenoxy resin in which a reaction product of the same bisphenol and epichlorohydrin is incorporated.
[188] At least one polyurethane resin is preferably used as a binder for a magnetic material.
[189] Suitable polyurethane resins contain at least one isocyanate-containing component selected from the diisocyanates, polyisocyanates and isocyanate prepolymers described above as polymerized units. Suitable di-, tri- and polyisocyanates and isocyanate prepolymers are as described above. The polyurethane resin also contains, as polymerized units, at least one compound selected from compounds containing at least one active hydrogen atom per molecule. It is selected, for example, from the abovementioned amines, polyamines, diols, triols, polyols and amino alcohols. These polyurethane resins also contain, as polymerized units, compounds containing two or more end groups which are generally reactive towards isocyanate groups and which additionally contain at least one additional functional group per molecule. These include, for example, a compound having at least one alpha, beta-ethylenically unsaturated double bond and / or epoxy action, a polymer having at least two end groups reactive with isocyanate groups, at least two end groups reactive with isocyanate groups A compound having at least one polar functional group selected from a carbonyl group, a sulfo group, a phosphonic acid group, a phosphoric acid group, an alkali metal and an alkaline earth metal salt thereof, an amino group and a quaternary ammonium group per molecule, and a mixture thereof.
[190] Suitable polyurethane resins are binders for magnetic materials obtainable by crosslinking polyisocyanates with hydroxyl-containing polyurethane prepolymers, described in documents DE-A 32 27 163 and DE-A 32 27 164. The polyurethane prepolymer is a thermoplastic polyurethane having an OH number of 10 to 120 (or 30 to 160) prepared from the following components:
[191] IA. 1 mole of polyol having a molecular weight of 400 to 4000,
[192] IB. 0.2 to 10 water (or 0.2 to 9 mol) diols having 2 to 18 carbon atoms,
[193] IC. 0.1 to 4 moles (or 0.2 to 10 moles) of primary or secondary amino alcohols having 2 to 20 carbon atoms,
[194] ID. If desired, from 0.01 to 1 mole of triols having from 3 to 18 carbon atoms and
[195] Ⅱ. 1.20 to 13 moles of a diisocyanate having 6 to 30 carbon atoms and the ratio of the NCO groups in the diisocyanate being 65 to 95% of the OH and NH group equivalents based on the components IA to ID.
[196] Some or all of component IB has a primary or secondary amino group and can be replaced by a diamine or amino alcohol corresponding to component IC. These components serve to form hydroxyl-containing urea groups at the chain ends of the polyurethane prepolymer. Suitable binders B) are also mixtures of binders comprising a hydroxyl-containing polyureaurethane as described in DE-A 32 37 163 as a binder mixture and a physically drying binder based on, for example, a vinyl-formaldehyde.
[197] Another suitable binder is the polyurethane binder described in document DE-A 39 29 164 and is a tetrahydrofuran-soluble, isocyanate-free, branched chain polyurethane containing fluorine groups, hydroxyl-containing ureas at the chain ends and a molecular weight of 4000 to 30,000 As a base material. This polyurethane binder is prepared from the following components:
[198] A) 1 mole of a polyol having a molecular weight of 400 to 4000,
[199] B) 0.3 to 9 moles of a diol having 2 to 18 carbon atoms,
[200] C) from 0.01 to 1 mol of triols having from 3 to 18 carbon atoms,
[201] D) 0.001 to 0.4 moles of a perfluoro compound having two terminal groups reactive with isocyanate and a molecular weight of 300 to 4000,
[202] E) 1.25 to 13 moles of a diisocyanate having from 6 to 30 carbon atoms and a ratio of NCO: OH of all of components A, B, C, and D of from 1.05: 1.0 to 1.4:
[203] F) 0.1 to 4 moles of primary or secondary amino alcohols having from 2 to 20 carbon atoms.
[204] In the formation of the prepolymer having a hydroxyl group at the terminal of the chain, the components A to E are reacted to obtain an isocyanate-containing intermediate, which is reacted with the aminoalcohol F. In contrast to DE-A 39 29 164, two terminal groups which are reactive towards isocyanates and from 0.01 to 0.4 moles of an organo-functional polysiloxane having a molecular weight of from 300 to 4000 are used as component D) Polyurethane is also suitable.
[205] Other suitable binders are described in German patent application P 197 57 670.2 and include one or more polyisocyanates in combination with at least one isocyanate-free polyurethane prepolymer containing at least three active hydrogen atoms, two or more hydroxyl groups and at least one Is a polyurethane resin obtainable by reacting with a prepolymer having a tertiary amino group and / or a secondary amino group.
[206] The above steps are incorporated herein by reference in their entirety. The binder for the magnetic material may further contain an auxiliary binder which is physically dried if necessary. Such physically drying auxiliary binders are known in principle. These are hydrolyzed vinyl ester polymers and polyvinylformal binders prepared by reacting the resulting vinyl alcohol polymerizer with formaldehyde. The polyvinylformer conveniently has a vinyl formamide content of at least 65% by weight, in particular at least 80% by weight. Particularly suitable polyvinyl formal contains 5 to 13% by weight of a vinyl alcohol group and 80 to 88% by weight of a vinyl formate group and is used at 20 DEG C with a solution of 5 g of polyvinylformal in 100 ml of phenol / toluene (1: 1) And a viscosity of from 50 to 120 mPa.s, measured in accordance with known methods, in addition to the polyvinyl formal, for example, vinyl chloride and diol mono (meth) acrylate or di (Meth) acrylate copolymers which can be prepared by solution copolymerization or suspension copolymerization of vinyl chloride / diol mono- or di (meth) acrylate. Diol mono- or diacrylates or mono- or dimethacrylates used for this purpose are prepared by reacting acrylic acid or methacrylic acid with the corresponding molar amounts of aliphatic diols having from 2 to 4 carbon atoms such as ethylene glycol, 4-butanediol and, preferably, propanediol, preferably propanediol containing 1,3-propanediol and 0 to 50% by weight of 1,2-propanediol. The copolymer advantageously has a vinyl chloride content of about 50 to 95 weight percent and a diol acrylate or methacrylate content of about 5 to 50 weight percent. Particularly suitable copolymers preferably have a vinyl chloride content of about 70 to 90% by weight and a diol monoacrylate or monomethacrylate content of 10 to 30% by weight. A 15% strength solution of a particularly suitable copolymer, such as a vinyl chloride / propanediol monoacrylate copolymer, has a viscosity of about 30 mPa.s at 25 DEG C in a mixture of the same minor skins of tetrahydrofuran and dioxane. Particularly suitable K values for the products are generally from 3 to 50, preferably about 40. [
[207] In addition, phenoxy resins having repeating units of the following formula can advantageously be used as auxiliary binders:
[208]
[209] Where n is about 100.
[210] These are, for example, the product Epicote of Shell Chemical Co. Co. or Epoxy resin PKHH of Union Carbide Co. ≪ / RTI >
[211] The above-mentioned cellulose ester bonding system is suitable as an auxiliary binder. For example, the use of a vinyl chloride copolymer having a sulfonate group according to US-A 4,748,084 as an auxiliary binder has proven to be advantageous and the copolymer is commercially available from Nippon Zeon, .
[212] According to a preferred embodiment, the binder used according to the invention contains from 0 to 30% of a dispersing resin. Suitable dispersing resins are described in DE-A 195 16 784, DE-A 41 41 848 and DE-A 44 46 383, the entire contents of which are incorporated herein by reference.
[213] Preferred binders for magnetic materials are those containing these dispersing resins in an amount of from 5 to 25% by weight, preferably from 10 to 20% by weight, based on the total amount of binder.
[214] The further processing of the binder mixture containing the magnetic material and the auxiliary agent to obtain the magnetic recording medium is carried out by the known method itself.
[215] Such as γ-iron (III) oxide, finely divided magnetite, ferromagnetic non-doped or doped chromium dioxide, cobalt-modified gamma -iron (III) oxide, barium ferrite or ferromagnetic metal particles can be used as the anisotropic magnetic material. Cobalt-modified or unmodified y-iron (III) oxides and ferromagnetic chromium dioxide and metal pigments are preferred, especially those with no pointed dendrites. The use of metal pigments is particularly preferred. The specific surface area is generally 15 m2 / g (BET method) or more, preferably 30 to 200 m2 / g.
[216] Binders for magnetic materials can be used in formulations without further use of low molecular weight dispersants. However, it is also possible to add small amounts of dispersants, for example lecithin, zinc oleate or zinc stearate.
[217] In addition, the magnetic layer may contain minor amounts of additives such as lubricants and / or fillers that can be mixed during dispersion of the magnetic material or during the manufacture of the magnetic layer. Examples of such additives include fatty acid or isomerized fatty acids such as fatty acid esters such as stearic acid, first to fourth metal salts of the Periodic Table of Elements and butyl stearate, or waxes, silicone oils, and carbon black. have. The amount of additive is conventional and is generally less than 10% by weight based on the total amount of magnetic layer.
[218] The ratio of the magnetic material to the binder in the new recording material is about 1 to 12 parts by weight, especially 3 to 8 parts by weight, of the magnetic material per 1 part by weight of the total binder.
[219] The magnetic layer is similarly applied to a substrate having one or more priming layers by conventional methods known to those skilled in the art. Similar to the application method for the priming layer, a casting mixture which is a dispersion of the magnetic material in one or more binders, preferably one or more additional auxiliary binders and / or additional additives is added or not added, is prepared, Is applied to the installed non-magnetic substrate material. The preparation of the magnetic pigment dispersion can be carried out analogously to the preparation of the carbon black-containing coating material in a conventional dispersing apparatus. The dispersion is applied, after filtration, if necessary, to a moveable nonmagnetic substrate material by one of the conventional coating apparatuses described above. When a binder based on polyurethane is used, the coating material can generally be applied on a non-magnetic substrate at high speed. Thereafter, the coating is dried at about 60 to 120 캜, preferably about 80 to 110 캜, calendered, and optionally post-cured. The application speed is generally about 1 to 1500 m / min, preferably 100 to 100 m / min, especially 300 to 900 m / min. Typically, the magnetic orientation is performed before the liquid magnetic dispersion is dried on the substrate. The magnetic layer can be calendered and compressed, if necessary after a predetermined residence time, by passing between heated and polished rolls on a conventional calendering machine at elevated temperature and, if necessary, pressing. The temperature during calendering is from about 60 to 120 캜, preferably from about 70 to 100 캜, as in the case of drying. The thickness of the magnetic layer is generally about 0.5 to 20 占 퐉, preferably about 1 to 10 占 퐉. In the case of the manufacture of magnetic tapes, the coated film is slit in the longitudinal direction to the typical width, generally in inches.
[220] The following non-limiting examples illustrate the invention.
[221] Example 1 (New binder composition)
[222] First, 30.0 kg of a solvent mixture containing tetrahydrofuran and dioxane (1: 1) was taken in a stirrer vessel equipped with a high-speed stirrer at room temperature, and a polyurethane acrylate solution ¹⁾ (1: 1 tetrahydrofuran / dioxane 20.0 % By weight), trimethylolpropane triacrylate (1.18 kg), ethylene glycol diacrylate (0.51 kg), bisphenol A diglycidyl ether diacrylate (0.9 kg), N-vinylcaprolactam solution (1: 1 tetrahydrofuran (Weight concentration of 50.0% in dioxane), 0.4 kg of ethyl acrylate and 1.0 kg of a polyester diol (molecular weight of about 20,000, DINAPOL L206, manufactured by Fles Trousoft Aktien Gesher Shaft) and an additional solvent (1 : 1 tetrahydrofuran / dioxane) was introduced with stirring. Thereafter, 5.50 kg of tetrahydrofuran / dioxane, 2.50 kg of leveling agnet (Fluorad ) FC 430), 0.01 kg of 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one (Irgacure 907, Cibaspelchi alitaten- Kg, and 0.025 kg of isopropylthioxanthone (QuanTacure ITX, Shell Chemical) was added with vigorous stirring.
[223] The thus-obtained non-colored dispersion was applied to a polyethylene terephthalate film having a thickness of 36 탆 at a speed of 45 m / min by a conventional knife coater and dried in a drying tunnel of 4 m length at 80 캜. A layer of about 1 탆 thick was then cured in air by passing it under a UV lamp (200 watts / cm, wavelength 200-400 nm). The UV cured adhesion promoting layer thus obtained was insoluble in tetrahydrofuran / dioxane (1: 1) and free from defects. This was immediately overcoated with a conventional magnetic dispersion (in tetrahydrofuran / dioxane (1: 1)) with iron oxide as the base. The magnetic recording medium thus produced was defect-free and exhibited excellent adhesive strength.
[224] Example 2 (New binder composition and coating material)
[225] First, 26.0 kg of a solvent mixture containing tetrahydrofuran and dioxane (1: 1) was taken in an agitated vessel equipped with a high-speed stirrer at room temperature, and a solution of polyurethane acrylate solution ¹⁾ (1: 1 tetrahydrofuran / dioxane 20.0 % By weight), 0.94 kg of trimethylolpropane triacrylate, 0.40 kg of ethylene glycol diacrylate, 0.72 kg of bisphenol A diglycidyl ether diacrylate, a solution of N-vinylcaprolactam (1: 1 tetrahydrofuran (Weight concentration of 50.0% in dioxane) and 0.32 kg of ethyl acrylate and 1.0 kg of a polyester diol (molecular weight of about 20,000, DINAPOL L206, manufactured by Friedrich Aktau GmbH & Co. KG) and an additional solvent 1 : 1 tetrahydrofuran / dioxane) was introduced with stirring. Thereafter, 5.0 kg of tetrahydrofuran / dioxane, 5.0 kg of leveling agent (Fluorad ) FC 0.01), 0.01 kg of 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one (Irgacure 907, Cibas felt alitaten- , 0.29 kg of isopropylthioxanthone (Quantacure ITX, manufactured by Shell Chemical), and 0.01 kg of 2,4,6-dimethylbenzoyldiphenylphosphine oxide (lucylline TBO, manufactured by BASF Aktien Gesher Shaft) The mixture was added with vigorous stirring. Thereafter, 1.35 kg of conductive carbon black (XL72, BET surface area 45 m 2 / g) and 50% by weight dispersion resin based on polyurethane acrylate having dispersed active SO ₃ Na groups (tetrahydrofuran / dioxane 1 : 1)) was vigorously stirred and stirring was continued for another half hour.
[226] The thus-obtained carbon black dispersion was applied to a polyethylene terephthalate film having a thickness of 36 탆 at a speed of 45 m / min by a conventional knife coater and dried in a drying tunnel at 80 캜 at a length of 4 m. A layer of about 1 탆 thick was then cured in air by passing it under a UV lamp (200 watts / cm, wavelength 200-400 nm). The UV cured adhesion promoting layer thus obtained was insoluble in tetrahydrofuran / dioxane (1: 1) and free from defects. This was immediately overcoated with a conventional magnetic dispersion (in tetrahydrofuran / dioxane (1: 1)) with iron oxide as the base. The magnetic recording medium thus produced was free from defects and exhibited excellent adhesive strength and exhibited better conductivity than 10 times the adhesion promoting layer containing no carbon black.
[227] ¹⁾ 16.5% by weight of polyurethane acrylate obtained from the following components in a tetrahydrofuran / dioxane (1: 1)
[228] 9.99 kg of toluene diisocyanate,
[229] 82.76 kg of a polycarbonate diol having a MW of about 2000,
[230] 54.87 kg of a polyester diol with a MW of 20,000 (Dynapol L206 from Foss Troisdorf Aktiengesellschaft)
[231] 2 moles of ethylene oxide and 0.5 mole of bisphenol A (Dianol ) 22) 28.35 kg of the addition product with 1 mole,
[232] 6.5 kg of 1,6-hexanediol,
[233] 0.47 kg of trimethylolpropane,
[234] 27.30 kg of bisphenol A diglycidyl ether diacrylate (Diacrylate of Epicot 828, Shells)
[235] 2.88 kg of butanediol monoacrylate,
[236] 53.10 kg of diphenylmethane diisocyanate.
[237] Comparative Example 1
[238] The method corresponds to Example 2 except that 2,4,6-dimethylbenzoyldiphenylphosphine oxide was not added as a photoinitiator. The adhesion promoting layer thus obtained was still soluble in tetrahydrofuran / dioxane (1: 1) and tacky, and the magnetic dispersion applied as a protective coating mixed with an adhesion promoter was useless.
[239] Comparative Example 2
[240] The method was similar to that of Example 2 except that vinylcaprolactam was not used in the preparation of the adhesion promoting layer. The adhesion promoting layer was still soluble in tetrahydrofuran / dioxane (1: 1) and was useless.
[241] Comparative Example 3
[242] The method was similar to that of Example 2 except that the polyurethane acrylate with dispersing activator was not used in the preparation of the adhesion promoting layer. The dispersed carbon black was poorly dispersed in the adhesion promoting layer, and small humps and spots were formed in the adhesion promoting layer. The magnetic recording medium obtained after protective coating with a magnetic dispersion based on iron oxide had many defects and was useless.

权利要求:
Claims (12)
[1" claim-type="Currently amended] a) at least one polyurethane acrylate having an average molecular weight of 10,000 to 80,000 and an average of 4 to 15 UV-curable , -ethylenically unsaturated double bonds per molecule,
b) a molecular weight of from 254 to 1000, and at least one compound having three UV-curable , -ethylenically unsaturated double bonds per molecule,
c) at least one compound having a molecular weight of from 170 to 1000 and two UV-curable alpha, beta -ethylenically unsaturated double bonds per molecule,
d) at least one , - ethylenically unsaturated compound selected from N-vinyl amide, N-vinyl lactam, vinyl- and allyl-substituted heteroaromatic compounds and mixtures thereof, and
e) optionally, at least one ester of an alpha, beta -ethylenically unsaturated monocarboxylic acid and an aliphatic or cycloaliphatic C ₁ to C ₂₀ monoalcohol.
[2" claim-type="Currently amended] The method according to claim 1,
- 0.003 to 0.015 mol of one or more polyurethane acrylates a),
- 0.2 to 1.5 mol of one or more compounds b),
- 0.2 to 1.8 mol of at least one compound c),
- 0.1 to 4.0 mol, preferably 0.3 to 4.0 mol, of at least one , - ethylenically unsaturated compound d),
- 0 to 4.0 mol of at least one ester e).
[3" claim-type="Currently amended] The binder composition according to claim 1 or 2, wherein the content of UV-curable , -Ethylenically unsaturated double bonds is from 2.5 to 7 mol, preferably from 4.0 to 6.0 mol, per 1000 g of binder composition.
[4" claim-type="Currently amended] 4. A binder composition according to any one of claims 1 to 3, characterized in that the average double bond functionalities are not more than 1.8, preferably not more than 1.6 per molecule, based on components a) to e).
[5" claim-type="Currently amended] I) at least one binder composition according to any one of claims 1 to 4,
Ii) at least one photoinitiator,
Iii) one or more pigments selected from carbon black, non-magnetic or abbreviated metal oxides and mixtures thereof, and mixtures comprising carbon black and one or more magnetic pigments,
Iv) at least one polyurethane (meth) acrylate having a dispersing active group, and
V) UV-curable coatings, if necessary, comprising one or more polyesters.
[6" claim-type="Currently amended] 6. Coating according to claim 5, characterized in that a photoinitiator mixture comprising at least one -Cutter, at least one H-extractant and at least one acylphosphine oxide or sulfide is used as component ii).
[7" claim-type="Currently amended] The process of claim 6, wherein the photoinitiator mixture comprises 75-98 wt% of an alpha -cutter, 1 to 24 wt% of an H-extractant, and 1 to 24 wt% of an acylphosphine oxide or sulfide Coating material.
[8" claim-type="Currently amended] The method of claim 6 or 7, wherein the -Cutter is selected from the group consisting of benzoin, benzoin ether, -Alkylbenzoin ether, benzyl ketal, -Acyloxime ester, acetophenone, dialkoxyacetophenone, , Hydroxycycloalkylphenones, heterocycloalkylphenones, and mixtures thereof. ≪ Desc / Clms Page number 13 >
[9" claim-type="Currently amended] 9. The process according to any one of claims 6 to 8, wherein the H-extract is selected from the group consisting of benzophenone, alkylbenzophenone, halogenated benzophenone, alkoxybenzophenone, benzyl, Michler's ketone, anthraquinone, anthraquinone derivatives, A thioxanthone derivative, a thioxanthone derivative, a thioxanthone derivative, and a mixture thereof.
[10" claim-type="Currently amended] 9. A photoinitiator mixture as claimed in any one of claims 6 to 9, wherein the H-extractant is selected from benzyl, microkeratone, anthraquinone, anthraquinone derivatives, thioxanthones, thioctone derivatives and mixtures thereof.
[11" claim-type="Currently amended] Use of a photoinitiator mixture according to claim 10 or a photoinitiator mixture as defined in any one of claims 6 to 9 for curing a carbon black-containing coating material by UV radiation.
[12" claim-type="Currently amended] A magnetic recording medium comprising a nonmagnetic substrate and at least one magnetic recording layer, wherein the recording layer comprises a finely divided ferromagnetic powder dispersed in a binder and is applied onto a priming layer on a substrate, 10. A magnetic recording medium obtained from at least one coating material which is cured by UV according to any one of claims 1 to 9.

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同族专利:

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公开号 | 公开日

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WO2000028531A1|2000-05-18|

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DE19851567A1|2000-05-11|

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EP1141952A1|2001-10-10|

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NO20012258L|2001-07-06|

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AU1033900A|2000-05-29|

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NO20012258D0|2001-05-08|

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US20020022130A1|2002-02-21|

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JP2002529880A|2002-09-10|

引用文献:

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公开号 | 申请日 | 公开日 | 申请人 | 专利标题

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法律状态:
1998-11-09|Priority to DE19851567.7

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1998-11-09|Priority to DE19851567A

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1999-10-08|Application filed by 프리드리히 베케비츠, 엠테크 마그네틱스 게엠베하

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1999-10-08|Priority to PCT/EP1999/007554

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2001-08-09|Publication of KR20010075691A

优先权:

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申请号 | 申请日 | 专利标题

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DE19851567.7|1998-11-09|

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DE19851567A|DE19851567A1|1998-11-09|1998-11-09|Binder composition for magnetic recording media and photoinitiator mixture curable by UV radiation|

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PCT/EP1999/007554|WO2000028531A1|1998-11-09|1999-10-08|Uv-radiation-hardenable binder composition for magnetic recording media and photoinitiator mixture|