• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Oxymethylene copolymers molding compositions with low portions of residual formaldehyde are produced by heating the polymerizate melts treated with chemical stabilizers in an apparatus in which there are continuously presented new polymerizate surfaces under reduced pressure. The heating of the polymerizate melt takes place in a thin layer evaporator for highly viscous media during an average residence time of 30 to 120 seconds at an average rate of shear between 500 and 2000 s-1 and at a pressure Pabs of at most 150 mbar. The escaping gases and vapors are drawn off countercurrent to the polymerizate melt.
    公开号:SU852177A3
    申请号:SU792783204
    申请日:1979-07-09
    公开日:1981-07-30
    发明作者:Аманн Херберт；Морлок Герхард；Траутвайн Хелльмут
    申请人:Дегусса Аг (Фирма)；
    IPC主号:
    专利说明:

    The invention relates to the production of acetal resins, in particular, to the technology for producing oximethylene polymer polymer molding masses, and can be used in chemical washing. A known method for producing oximethylene copolymer molding masses by mechanical processing of polymer melt mixed with chemical stabilizers under vacuum, PR 195-245 C, removing evolved and melting gases and vapors, while processing is carried out in devices that open all new surface areas. melt, for example in a twin-screw extruder Cll. However, the molding materials treated by this method contain a relatively large proportion of the residual forms of aldehyde, which is often the cause of the subsequent processing of unpleasant odors, the formation of sediments in pressure molds and the production of defective molded products. The purpose of the invention is to reduce the residual formaldehyde content in the final product. This goal is achieved by the fact that in the method of obtaining oximethylene copolymer molding masses by mechanical processing of a polymer melt mixed with chemical stabilizers under vacuum at 195-2450 ° C, with evolved gases and melts released from the melt, the processing of the melt is carried out in a thin layer auger evaporator for high concentrations. with a melt longevity of 50–70 s in it, a shear gradient of 950–1500 s and an absolute pressure of 27–135 mbar, and the gases and vapors released from the melt are removed countercurrently to the engine. iju melt. The hydroxymethylene copolymers used are copolymers of trioxane and at least one compound copolymerizable with trioxane, preferably dioxolane or dioxepane. The proportion of these compounds in the final copolymer may be from 0.01 to 20 mol.%. The viscosity index of the oxymethylene copolymers used, measured in a polymer solution in dimethylformamide containing 2% by weight of diphenylamine, at 135 ° C and a concentration of 0.5 g (100 ml) should usually be at least 30 ml / g. The melting point of the copolymer crystallite is in the range of 140-180 ° C, preferably 150-170 ° C, the specific gravity is 1.38-1.45 g / preferably 1.4-1.43 g / ml (measurement is carried out according to DIN 53 479). To carry out the proposed method, crude oxymethylenscope measures are mixed with hic;} 1 stabilizing antioxidant congestions, heat stabilizers and basic substances. Antioxidants can be used as such, but preferably in a mixture with heat stabilizers and / or base substances. Stabilizers must at the same time have high efficiency and low volatility as possible. Chemical stabilizers are introduced during melting or earlier into an appropriate mixer. All heated, closed mixers used in conventional thermoplastics processing, preferably continuously operating devices, such as extruders, are suitable for melting the hydroxymethylene copolymer and for mixing with chemical stabilizers (and other necessities with other additives). In cases where it is advisable to carry out a pre-degassing process in a heated mixer before, during or after melting. Chemical stabilizers can be used as a dry powder, concentrate (dispersion masterbatch) or solution. In addition to chemical stabilizers, other materials are also added to oxymethylene copolymers, such as ultraviolet absorbers or light shielding agents: anti-slip agents, such as graphite, molybdenum disulfide, polytetrafluoroethylene, perfluorinated organic compounds, oils or periodically, agents that promote processing, such as esters, amides or salts of fatty acids, nucleating agents, for example talc, antimony oxide, finely divided pyrogenic silicic acids, fillers and / or reinforcing agents in powdered, fibrous leaf-like or. other form, dyes and / or flame retardants. The introduction of such additive additives is carried out before degassing or, especially when processing relatively large amounts of material, only after degassing the oxymethylene copolymers. After melting, the polymer melt that is formed is transferred to a thin layer evaporator for a highly viscous medium, where it is spread evenly by the walls of the rotating rotor with the help of two rotary rotor bodies, stratified to form new surface areas and transported further. At the discharge end of the thin-layer evaporator, there is a vacuum-tight transport device, such as a gear, a screwdriver or an extruder pump, which ensures melt discharge. The recovered melt can then be processed by conventional methods, for example, pressed into bars, which are granulated before and after curing. 1. Dosignable thermostable parts. 100 g of the crude hydroxymethyl copolymer is heated in countercurrent to remove unreacted monomers and to inactivate the catalyst with a mixture of 250 ml of a 1% w / w aqueous solution of ammonium carbonate and 250 ml of methanol, for 1 hour. Next, the composition is washed with water and then methanol, filtered, and dried at 65 ° C for 5 h and Pd5c at about 30 mbar. Weight loss in percent determines the content of extractable parts. A sample of the obtained product (about 0.5 g) is weighed in a test tube with a diameter of 10 mm and then placed in a washable cylindrical glass apparatus with an inner diameter of 16 mm, the discharge pipe is immersed in a tank filled with water. After purging with nitrogen of the highest purity (20 minutes, about 110 ml / min), the glass apparatus is immersed with further nitrogen start-up for 2 hours in the oil bath, the temperature of which is maintained at a level. The glass apparatus is then cooled in air for 20 minutes and the tube is withdrawn from it with the sample, which is re-weighed. Weight loss in percent is considered a thermally unstable part. 2. Residual formaldehyde. 10.0 g of the hydroxymethyl copolymer are heated with 50 ml of distilled water with stirring and cooling of the reflux for 1 hour in a heating bath, the temperature of which is maintained; at the level of 100 + 0.5 ° C. Then the reflux cooler is rinsed with water, the oxymethylene copolymer is filtered and washed. The filtrate collected in a 100 mm volumetric flask is supplemented after cooling to room temperature with distilled water to 100 ml. Extracted formaldehyde is determined by a photometric method using a reagent solution consisting of 150 g of ammonium acetate (analytical grade), 3 ml of acetic acid (analytical grade), 2 ml of freshly distilled acetylacetone (analytical grade) and 1000 ml of distilled water. Such a solution can be consumed for at least 1 month.
    Into a 100-mm volumetric flask, pour in 20 ml of the reagent solution and 3.0 ml of the extract. Then add water to 100 ml and mix everything well. Formaldehyde is converted into yellow colored diacetyl dihydrolutidine with a reagent. The extinction of the solution is measured using a filter from 400 to 420 nm (for example, Nd405nm) with a layer thickness of 2 cm relative to distilled water. From the obtained extinction value, using the Reference curve for formaldehyde of known concentration, determine the amount of formaldehyde extracted, which in this case is equal to the amount of residual formaldehyde.
    3. Index in viscosity.
    The viscosity index is determined for pacTBOj3OB in dimethylformamide (containing 2% diphenylamine additive) at a concentration of 0.5 g / 100 ml.
    4. The cure time.
    In a differential scanning calorimeter, 3.0 mg test substance is heated at a rate of 40 ° C / min to 190 ° C. This temperature is maintained for 5 minutes, and then also at a rate of 40 ° C / min it decreases to 149s. After reaching 149s, the time required for access maximum heat flow rate. This time is the curing time.
    5. Melting Index (MF1). The melting index is determined by
    DIN 53735 at 190 ° C and a load of 2.16 kg.
    Example 1. Oximethyl hexopolymer containing 3.1 mol.% Of 1,3-dioxepane units, with a viscosity index of 61 MP / g, in which 7.8% by weight of water extractable and 3.0% by weight of thermostable parts remain, is mixed with the following amount (based on the extracted hydroxymethylene copolymer without unstable parts) additives: 0.4% by weight of the condensation product of ethylene urea isophthalic acid diamide formaldehyde; 0.4% by weight of N, N-hexamethylene-bis-3- (3, 5-di-tert-butyl-4-hydroxyphenyl) -propionamide and 0.1% by weight of aqueous O, 2% sodium carbonate solution .
    This mixture is melted in a single-screw extruder (screw diameter 60 mm, length 28 diameters) and passed through a heated tube to a vacuumized thin-layer evaporator with a diameter of 150 mm (Filtruder brand HS 50 from Luva). The degreased product is withdrawn by a gear pump from a thin layer evaporator and squeezed through a thin-walled die plate. Approximately 2 millimeter rods are passed through a water bath | Well and crushed in a roller granulator. The gases and vapors sucked out of the thin-layer evaporator are partially absorbed by the injected water, and are partially condensed in the condenser installed further.
    Operational parameters of the extdder:
    Body temperature, 0s150; 180; 190} 2
    Speed, rev / min50
    Conditions of the experiment at the time of degassing:
    Housing temperature Filtruder, ° C 205 Rotor speed, rpm 190 Slave bar47 Melting temperature at the inlet, ° C 195 Melting temperature at the output, the part (before the die), ° C 236 Shear gradient, 1500 The average dwell time in the treatment area, c 70 The average thickness of the layer, mm 1.5. The output of the granulate is 53 kg / h. The product has the following characteristics:
    Melting index, g / 10 min8,8
    The residual content of formaldehyde, h / mln.67
    Weight loss with two. hourly heated to% in nitrogen atmosphere 0.01 in air1.6
    Example 2. The experiment was carried out under the conditions of Example 1, but the pressure of Rob was 135 mbar.
    The residual formaldehyde content in the resulting granulator is 133 ppm,
    Example 3. The experiment is conducted under the conditions of Example 1.
    Extruder performance data:
    Case temperature, OC 165, 19Q; 180; 2 Speed, rpm75 Test conditions during degassing:
    Housing temperature
    221 Filmtruder, Wasps Roto120 47 ra rpm
    Ravs. Mbar Melting point at the inlet, ° C
    220 Melting point at the exit (before
    228 spinneret), 0-С Gradient of shift, s
    laoo The average residence time in the treatment zone, with the average layer thickness, mm 2.5. The output of the granulate is 80 kg / h. 1034 / jvmH residual formaldehyde remains in the product. .The loss in weight is when heated to 220 ° C in an a-atot atmosphere of 0.01%, in air. Example 4. The experiment was carried out as in Example 3. Experimental conditions during degassing: Temperature of the film film trader, C221 Rotor speed , rpm190 Rdbs mbar47 Melting point at the inlet, ° C 200 Melting point at the outlet (in front of the nozzle), OC 238 Shear gradient, 1500 Average soak time in the processing zone, with 57 Average layer thickness, mm 2.0 The resulting product contains 68 ppm of residual formaldehyde. Example 5. The experiment was carried out as in example 1 with an extruder rotor speed of 100 rpm. Conditions for conducting an experiment with degassing: Temperature of the Filtruder's body, 0s253 Rotor speed, rpm120 Slave Mbar27 Shear gradient, s 950 Average dwell time g s 55 Average layer thickness, mm 2.5 Grade production capacity 109 kg / h 44 residual form aldehyde remain in the product. When heated for two hours, the product loses 0.07% in a nitrogen atmosphere and 1.2% of its weight in air. Example b. The test was carried out as in example 1. Operational data extruder Extruder body temperature 170; 190; 180; 200 Speed,. rev / min. 125 Conditions of experience during degassing hull temperature, C 255 Rotor speed, rpm 120 Shear gradient, s 950 Average holding time, c50 Average layer thickness, mm 3.0 Granule output reaches 133 kg / h. The residual content of aldehyde forms in the product is 70 ppm, the weight loss during two-hour heating to 220 ° C in a nitrogen atmosphere is 0.06%, in air - 1.1%. Example 7. Oxymethylene copolymer with 3.2 mol.% Of 1,3-dioxepane units and a viscosity index. 87 ml / g, containing 4.2% by weight of extractable water and 2.4% by weight of thermally unstable parts, is mixed with the following additives (based on the extracted oxymethylene copolymer without unstable parts): 0.4% by weight of melamine-formaldehyde copolycondensate ; 0.4 wt.% N, M-hexamethylene-bis-3- (3, 5-di-tert-butyl-4-hydroxyphenyl) -propionamide and 0.3 wt.% Aqueous 0.1% sodium carbonate solution . The mixture is smelted as indicated in Example 1, degassing and granulating. , Operating parameters of the extruder: Casing temperature, ° C 150; 190; 1 0; 215 Speed, rpm71 Conditions for conducting an experiment during the outgassing process: Body temperature, C 255 Rotor speed, rpm 120 Ra5s, mbar47 Melting point at the inlet, 216 Melting point in the water part (in front of the nozzle), C 245 Shear gradient. 950 Average dwell time, s 68 Average layer thickness; mm 2.5 Grail outlet is 82 kg / h. The product has a melting index of 2.5 g / 10 min, the residual formaldehyde content is 69 ppm, the weight loss after two hours exposure to 0% nitrogen atmosphere, 0.9% in air. Cure time 29 s. Comparative experience. The crude polymer described in Example 7 used with the heat stabilizers used is used. The product is melted in a twin-screw extruder (WSKs-57 brand ZSK-57; W Pfleyderer, auger diameter 57 mm, length 38 diameters, two digesters), and out-dried. The product is extruded with rods and then granulated. Operational data of the extruder: Casing temperature, "C 200; 252,256; 220,190 Speed, bb / min220 abs of the first zone160 of the second zone 27 Shpusk granulate is 41 kg / h. The product has a melting index (2.6 g / 10 MHHf, the residual formaldehyde content is 234 ppm, the weight loss after a two-hour exposure at 220 ° C in a nitrogen atmosphere is 0.06%, in air - 1.4%. Curing time is 46 s. Proposed The method makes it possible to significantly reduce the amount of residual formaldehyde in the target product. Foumula of the invention A method for obtaining oxymethylene copolymer molding masses by mechanical processing of polymer melt mixed with chemical stabilizers under vacuum at 1952459c with removal of melted and melt gases and vapors, so that, in order to reduce the residual formaldehyde content in the target product, melt processing is carried out in a thin-layer auger evaporator for a highly viscous medium with a melt holding time of 50- 60 s, a shear gradient of 950–1500 s, and an absolute pressure of 27–135 mbar, and from a melt stream, gases and vapors are removed in countercurrent to the melt motion. Sources of Information taken into account in examination 1; Accepted for the FRG. 1445273, cl. 39 in 51/22, publ. 1970.
    权利要求:
    Claims (1)
    [1]
    Claim *
    A method of producing oxymethylene-polymer-molding materials by mechanical processing of a polymer melt mixed with chemical stabilizers under vacuum at 1952450 ° C with the removal of gases and vapors released from the melt, with the aim of reducing the residual formaldehyde content in target product, processing - the melt is performed in a thin-film evaporator for high-viscosity screw Medium in the residence time in melt therein 50-60 s, a shear gradient 950-1500 s -1, and the absolute davI lenii 27-135 mbar and you elyayuschiesya melt gases and vapors removed countercurrent to the movement of the melt.
    类似技术:
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    同族专利:
    公开号 | 公开日
    DE2840679A1|1980-03-20|
    GB2030576A|1980-04-10|
    FR2436796A1|1980-04-18|
    IT1162421B|1987-04-01|
    IT7950275D0|1979-09-17|
    DE2840679C2|1982-03-18|
    SE7907737L|1980-03-20|
    BE878840A|1980-03-17|
    GB2030576B|1982-12-22|
    PL116522B1|1981-06-30|
    US4225703A|1980-09-30|
    DD146055A5|1981-01-21|
    PL218276A1|1980-06-02|
    JPS5543191A|1980-03-26|
    NL7905636A|1980-03-21|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
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    NL181364C|1975-09-10|1987-08-03|Degussa|METHOD FOR PREPARING POLYOXYMETHYLENE FORMULAS; SHAPED PRODUCTS.|JPS6152850B2|1979-05-28|1986-11-14|Mitsubishi Gas Chemical Co|
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    JPS58167608A|1982-03-29|1983-10-03|Asahi Chem Ind Co Ltd|Deactivation of polymerization catalyst|
    JPH0363965B2|1983-06-08|1991-10-03|Polyplastics Kk|
    JPS6213369B2|1983-06-17|1987-03-26|Polyplastics Kk|
    US4650692A|1985-11-01|1987-03-17|Ashland Oil, Inc.|Metal-sulfonate/piperidine derivative combination protective coatings|
    CN1035510C|1990-09-29|1997-07-30|化学工业部晨光化工研究院一分院|One-step process for after-treating molten polyformaldehyde|
    US5822868A|1995-09-12|1998-10-20|Hna Holdings, Inc.|Luminous flame of acetal polymers|
    JP3771008B2|1997-07-16|2006-04-26|ポリプラスチックス株式会社|Process for producing branched or cross-linked polyacetal resin|
    US20040063853A1|1998-04-08|2004-04-01|Stefan Disch|Polyoxymethylene moulding material with improved processing stability and a reduced emissions tendency|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    DE19782840679|DE2840679C2|1978-09-19|1978-09-19|Process for the production of oxymethylene copolymer molding compositions with a low proportion of residual formaldehyde|
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