• 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:
    Provided is a polyethylene powder that is used as a starting material to produce various molded articles not only having impact resistance and abrasion resistance compatible with each other but also having excellent transparency and excellent ease of finding stains. The polyethylene powder comprises, as a constituent unit, an ethylene unit and/or an ethylene unit and a unit of an @— olefin having 3 or more and 8 or less carbon atoms, and has a viscosity—average molecular weight of 1,000,000 or more and 10,000,000 or less, wherein a yellowness YI, a whiteness WI, and a density p of a sheet molded article under the compression molding conditions described in JIS K6936—2 satisfy the following Expression (1): 0.503(— YI)XWI/p<2.0 .…
    公开号:NL2027813A
    申请号:NL2027813
    申请日:2021-03-23
    公开日:2021-10-20
    发明作者:Hamada Yoshiaki
    申请人:Asahi Chemical Ind；
    IPC主号:
    专利说明:

    [0001] [0001] The present invention relates to a polyethylene powder and a molded article. Description of the Related Art
    [0002] [0002] It has been conventionally known that since a polyethylene powder, particularly an ultra-high-molecular weight polyethylene powder, has a high molecular weight as compared with general-purpose polyethylene, it is excellent in stretching processability, has high strength, has high chemical stability and is excellent in long-term reliability. From these reasons, the polyethylene powder, particularly an ultra-high-molecular weight polyethylene powder, is used as a starting material for molded articles, such as microporous membranes for separators of secondary batteries typified by a lead storage battery and a lithium-ion battery, and fibers.
    [0003] [0003] The polyethylene powder, particularly an ultra-high- molecular weight polyethylene powder, is excellent in various characteristics, such as impact resistance, abrasion resistance, sliding properties, low-temperature properties and chemical resistance, as compared with general-purpose polyethylene. On that account, the polyethylene powder, particularly an ultra-high-molecular weight polyethylene powder, is also used as a starting material for not only lining materials for hoppers, chutes and the like, bearings, gears and roller guide rails but also molded articles such as bone substitutes, bone conductive materials and osteoinductive materials.
    [0004] [0004] On the other hand, in the case of the ultra-high- molecular weight polyethylene powder, extrusion molding of a resin alone is difficult because the molecular weight is high, and therefore, compression molding (press molding) or molding with a special extruder such as a ram extruder is often carried out.
    [0005] [0005]
    [0006] [0006] In recent years, in various molded articles using, as a starting material, such a polyethylene powder as described above, demands for not only possession of excellent impact resistance and abrasion resistance but also improvement in transparency of the molded articles and capability of easily finding stains of those various molded articles (hereinafter, sometimes referred to as ease of finding stains of molded articles) are increasing.
    [0007] [0007] Then, in the light of the problem of the prior art, it is an object of the present invention to provide a polyethylene powder which makes impact resistance and abrasion resistance of various molded articles using the polyethylene powder as a starting material compatible with each other and from which molded articles excellent in transparency and excellent in ease of finding stains can be obtained.
    [0008] [0008] In order to solve the above problem, the present inventor (s) has earnestly studied, and as a result, has found that a polyethylene powder which has a viscosity- average molecular weight in the prescribed range and in which a yellowness YI, a whiteness WI and a density p of a sheet molded article under the compression molding conditions described in JIS K6936-2 satisfy the prescribed relationship can solve the above problem, and the inventor(s) has completed the present invention. That is to say, the present invention is as follows.
    [0009] [0009]
    [1] [1] A polyethylene powder comprising, as a constituent unit, an ethylene unit and/or an ethylene unit and a unit of an a-olefin having 3 or more and 8 or less carbon atoms, and having a viscosity-average molecular weight of 1,000,000 or more and 10,000,000 or less, wherein a yellowness YI, a whiteness WI, and a density p of a sheet molded article under the compression molding conditions described in JIS K6936-2 satisfy the following Expression (1):
    [2] [2] The polyethylene powder according to the above [1], wherein the a-olefin is 1-propene or l-butene, and the content of the o-olefin is 1.0 mol or less.
    [3] [3] The polyethylene powder according to the above [1] or [2], wherein the polyethylene powder has a bulk density of 0.30 g/mL or more and less than 0.60 g/mL.
    [5] [5] The polyethylene powder according to any one of the above [1] to [4], wherein in a melting integral curve by differential scanning calorimetry (DSC), a temperature at the time of 30% melting is 120°C or higher and 140°C or lower, a temperature at the time of 50% melting is 125°C or higher and 145°C or lower, and a temperature at the time of 70% melting is 130°C or higher and 150°C or lower.
    [6] [6] The polyethylene powder according to the above [5], wherein in the melting integral curve by differential scanning calorimetry (DSC), the temperature at the time of 50% melting is 130°C or higher and 140°C or lower.
    [7] [7] A molded article of the polyethylene powder according to any one of the above [1] to [6].
    [8] [8]
    [9] [9] The molded article according to the above [7], wherein the molded article is an extrusion molded article.
    [10] [10] The molded article according to the above [7], wherein the molded article is a stretch molded article.
    [11] [11] The molded article according to the above [7], wherein the molded article is a microporous membrane.
    [12] [12] The molded article according to the above [7], being a fiber.
    [0010] [0010] According to the present invention, there can be provided a polyethylene powder which makes impact resistance and abrasion resistance of various molded articles using the polyethylene powder as a starting material compatible with each other and from which molded articles excellent in transparency and excellent in ease of finding stains are obtained.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
    [0011] [0011] Hereinafter, embodiments for carrying out the present invention (referred to as "the present embodiments" hereinafter) will be described in detail.
    [0012] [0012] [Polyethylene powder] The polyethylene powder of the present embodiment comprises, as a constituent unit, an ethylene unit and/or an ethylene unit and a unit of an oa-olefin having 3 or more and 8 or less carbon atoms, and has a viscosity- average molecular weight of 1,000,000 or more and 10,000,000 or less, and a yellowness YI, a whiteness WI, and a density p of a sheet molded article of the polyethylene powder under the compression molding conditions described in JIS K6836-2 satisfy the following Expression (1).
    [0013] [0013]
    [0014] [0014]
    [0015] [0015] (Viscosity-average molecular weight) The polyethylene powder of the present embodiment has a viscosity-average molecular weight of 1,000,000 or more and 10,000,000 or less, preferably 1,200,000 or more and 9,500,000 or less, and more preferably 1,500,000 or more and 9,000,000 or less. Since the viscosity-average molecular weight is in the above range, abrasion resistance, heat resistance, impact resistance, strength, and molding processability can be made compatible with one another in a molded article using the polyethylene powder of the present embodiment as a starting material.
    [0016] [0016] The viscosity-average molecular weight (Mv) of the polyethylene powder of the present embodiment can be calculated from the following Expression (2) using an intrinsic viscosity [nq] (dl/g) determined by extrapolating reduced viscosities to a concentration 0, the reduced viscosities being determined using a plurality of solutions obtained by dissolving the polyethylene powder in decahydronaphthalene solutions in different concentrations under the temperature conditions of 135°C. Specifically, the viscosity-average molecular weight can be determined by the method described in the examples.
    [0017] [0017] The viscosity-average molecular weight of the polyethylene powder of the present embodiment can be controlled to be in the above numerical value range by adopting a method of allowing hydrogen to exist in the polymerization system or a method of adjusting the polymerization temperature in the polymerization step for the polyethylene powder.
    [0018] [0018] In a sheet molded article obtained from the polyethylene powder of the present embodiment under the compression molding conditions described in JIS K6936-2, a yellowness YI, a whiteness WI, and a density p satisfy the following Expression (1).
    [0019] [0019] (Bulk density) The bulk density of the polyethylene powder of the present embodiment is preferably 0.30 g/mL or more and
    [0020] [0020] (Total of magnesium, titanium and aluminum element contents) In the polyethylene powder of the present embodiment, the total of magnesium, titanium and aluminum element contents is preferably 1 ppm or more and 50 ppm or less, more preferably 2 ppm or more and 40 ppm or less, and still more preferably 3 ppm or more and 30 ppm or less.
    [0021] [0021] (Melting integral curve by DSC) In a melting integral curve of the polyethylene powder of the present embodiment by DSC (differential scanning calorimetry), it is preferable that a temperature at the time of 30% melting be 120°C or higher and 140°C or lower, a temperature at the time of 50% melting be 125°C or higher and 145°C or lower, and a temperature at the time of 70% melting be 130°C or higher and 150°C or lower. It is more preferable that a temperature at the time of 30% melting be 122°C or higher and 138°C or lower, a temperature at the time of 50% melting be 127°C or higher and 143°C or lower, and a temperature at the time of 70% melting be 132°C or higher and 148°C or lower. It is still more preferable that a temperature at the time of 30% melting be 125°C or higher and 135°C or lower, a temperature at the time of 50% melting be 130°C or higher and 140°C or lower, and a temperature at the time of 70% melting be 135°C or higher and 145°C or lower.
    [0022] [0022] (Other components) The polyethylene powder of the present embodiment may be used in combination with various known additives, as needed. Examples of the additives include a heat stabilizer, a lubricant and a hydrogen chloride absorbent.
    [0023] [0023] [Molded article] The molded article of the present embodiment is obtained by molding the above-mentioned polyethylene powder of the present embodiment.
    [0024] [0024] (Organic peroxide) The organic peroxide that is used when the polyethylene powder is molded has a function of an organic peroxide crosslinking agent.
    [0025] [0025] (Method for molding polyethylene powder, various molded articles) Examples of methods for molding the polyethylene powder of the present embodiment include, but are not limited to, compression molding (press molding), extrusion molding and stretch molding.
    [0026] [0026] [Method for producing polyethylene powder] A method for producing the polyethylene powder of the present embodiment is not particularly limited, and is, for example, a method for producing the polyethylene powder using common Ziegler-Natta catalysts or metallocene catalysts. Particularly a method for producing the polyethylene powder using Ziegler-Natta catalysts is preferable. As the Ziegler-Natta catalysts, those disclosed in [0032] to [0068] of the aforesaid Japanese Patent Laid-Open No. 2015-157905 can be used.
    [0027] [0027] The method for polymerizing a monomer in the production process for the polyethylene powder is, for example, a method in which ethylene or monomers containing ethylene and an Qg-olefin having 3 or more and 8 or less carbon atoms are polymerized by suspension polymerization. The suspension polymerization is preferable from the viewpoint of capability of efficiently removing heat of polymerization. In the suspension polymerization, an inert hydrocarbon medium can be used as a medium, and an olefin itself can also be used as a solvent.
    [0028] [0028] In usual, the polymerization temperature in the production process for the polyethylene powder of the present embodiment is preferably 20°C or higher and 100°C or lower, more preferably 30°C or higher and 95°C or lower, and still more preferably 40°C or higher and 920°C or lower. Since the polymerization temperature is 20°C or higher, industrially efficient production is feasible. On the other hand, since the polymerization temperature is 100°C or lower, continuously stable operations are feasible.
    [0029] [0029]
    [0030] [0030] It is also possible to carry out the polymerization step for the polyethylene powder of the present embodiment in two or more stages different in reaction conditions. The viscosity-average molecular weight of the resulting polyethylene powder can be controlled by adopting a method of allowing hydrogen to exist in the polymerization system or a method of changing the polymerization temperature, as described in West German Patent Application Publication No. 3127133. By adding hydrogen to the polymerization system as a chain transfer agent, it becomes possible to control the viscosity- average molecular weight in an appropriate range. When hydrogen is added to the polymerization system, the molar fraction of hydrogen is preferably 0.01 mol% or more and 30 mol% or less, more preferably 0.01 mol&% or more and 25 mol or less, and still more preferably 0.01 mol3 or more and 20 mol3 or less. In the present embodiment, other known components useful for producing the polyethylene powder can be contained in addition to such components as described above.
    [0031] [0031] In the polymerization for the polyethylene powder of the present embodiment, it is preferable to use an antistatic agent such as STATSAFE 3000 manufactured by Innospec Inc. in order to inhibit electrostatic adhesion of a polymer to the polymerization reactor. As the STATSAFE 3000, dilute one obtained by diluting it with an inert hydrocarbon medium can be added to the polymerization reactor by a pump or the like. In this case, the addition amount is preferably 0.1 ppm or more and 50 ppm or less, and more preferably 20 ppm or more and 50 ppm or less, based on the production of the polyethylene powder per unit time.
    [0032] [0032] As a method for drying the polyethylene powder of the present embodiment after the polymerization, a drying method without applying high heat is preferable from the viewpoint of prevention of deformation of a powder or fusion bonding of powder particles. The type of the dryer is preferably rotary kiln type, paddle type, a fluidized bed dryer or the like. The drying temperature is preferably 50°C or higher and 150°C or lower, and more preferably 70°C or higher and 100°C or lower. It is also effective to introduce an inert gas such as nitrogen to the dryer to accelerate drying, and specifically, the oxygen concentration in the dryer is preferably set to less than 100 ppm.
    [0033] [0033] [Use application of molded article] The polyethylene powder of the present embodiment can be processed by various processing methods. A molded article of the polyethylene powder of the present embodiment can be applied to various uses. Examples of main uses to which the molded article is preferably applied include microporous membranes, e€.d., separators for secondary batteries such as lithium-ion secondary batteries and lead storage batteries, fibers, lining materials for hoppers, chutes, etc. because of non-tackiness and low friction coefficient, and bearings, gears, roller guide rails, bone substitutes, bone conductive materials or osteoinductive materials, which require self-lubricating properties, low friction coefficient and abrasion resistance. Examples
    [0034] [0034] Hereinafter, the present embodiment will be described in more detail using concrete examples and comparative examples, but the present embodiment is in no way limited to the following examples and comparative examples.
    [0035] [0035] [Measuring methods and conditions] {1) Viscosity-average molecular weight (Mv) A viscosity-average molecular weight of a polyethylene powder was determined by the method shown below in accordance with ISO 1628-3 (2010).
    [0036] [0036] {2) Content of a-olefin unit Measurement of a content (mol%) of polymerization units derived from an a-olefin in a polyethylene powder was carried out in accordance with the method disclosed in G. J. Ray, et al. Macromolecules, 10, 773 (1977), and using a signal of methylene carbon observed in a +3C-NMR spectrum, the content was calculated from its integrated intensity.
    [0037] [0037] (3) Yellowness YI, whiteness WI Using a polyethylene powder, a compression molded sheet was prepared in accordance with the compression molding conditions for a specimen described in JIS K6936- 2, and a yellowness YI and a whiteness WI of the sheet were measured using a CR-20 Color Reader (manufactured by KONICA MINOLTA, INC.).
    [0038] [0038] (4) Bulk density A bulk density of a polyethylene powder was measured in accordance with JIS K-6721:1997.
    [0039] [0039] (5) Density (p) A density was measured in accordance with ASTM D
    [0040] [0040] {6) Total of magnesium, titanium and aluminum element contents The total of magnesium, titanium and aluminum element contents in a polyethylene powder was determined by pressure decomposing the polyethylene powder using a microwave decomposition device (model: ETHOS TC, manufactured by Milestone General K.K.), measuring element concentrations of magnesium, titanium and aluminum as metals in the polyethylene powder by an internal standard method using ICP-MS (inductively coupled plasma mass spectrometer, model: X Series X7, manufactured by Thermo Fisher Scientific), and calculating the sum of them.
    [0041] [0041] (7) Temperature at the time of melting of prescribed amount in melting integral curve by DSC Measurement of a melting integral curve of a polyethylene powder by DSC was carried out using DSC (manufactured by PerkinElmer, trade name: DSC 8000). In an aluminum pan, 8 to 10 mg of a polyethylene powder was introduced, then the aluminum pan was set in the DSC, thereafter, a melting curve obtained by holding the polyethylene powder at 50°C for 1 minute and then heating it up to 190°C at a temperature increasing rate of 10°C/min was integrated, and with the proviso that the percentage before the beginning of melting was 0% and the percentage at the time of completion of melting was 100%, temperatures at the time of 30% melting, at the time of 50% melting and at the time of 70% melting were determined.
    [0042] [0042] (8) Evaluation of ease of finding stains of molded article In a mold of 1 m square and a height of 3 cm in a hot press molding machine, a mixture obtained by adding 10 ppm of carbon black (manufactured by YONEYAMA YAKUHIN KOGYO Co., LTD.) to 28 kg of a polyethylene powder was introduced in a state of free fall, the mixture was compression molded at a preset temperature of 210°C and a gauge pressure of 10 MPa for 12 hours, and then the mixture was subjected to cooling process for terminating heating while keeping the pressure, thereby obtaining a molded article. The molded article was cut into products of 20 cm square, the resulting 25 cut products of 20 cm square were visually evaluated, and presence or absence of stains caused by carbon black was confirmed with the naked eye. The judgement criteria are as follows.
    [0043] [0043] {9) Evaluation of impact resistance Using a polyethylene powder, a compression molded sheet was prepared in accordance with the compression molding conditions for a specimen described in JIS K6936-
    [0044] [0044] (10) Evaluation of abrasion resistance A compression molded sheet was prepared in the same manner as in the above (9). The average cooling rate was changed to 1°C/min.
    [0045] [0045] [Catalyst Synthesis Example 1: Preparation of solid catalyst component [A]] (1) Synthesis of starting material (a-1) In an 8 L stainless steel autoclave having been thoroughly purged with nitrogen, 2,000 mL (equivalent to 2,000 mmol in terms of magnesium and aluminum) of a hexane solution of Mge(CsHs)12Al (C2Hs)z of 1 mol/L was introduced, and while stirring at 50°C, 146 mL of a n-
    [0046] [0046] (2) Synthesis of starting material (a-2) In an 8 L stainless steel autoclave having been thoroughly purged with nitrogen, 2,000 mL (equivalent to 2,000 mmol in terms of magnesium and aluminum) of a hexane solution of Mgs{(C4Hs)12Al1 (C2Hs)3 of 1 mol/L was introduced, and while stirring at 80°C, 240 mL of a hexane solution of methyl hydrogen polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) of 8.33 mol/L was pressure fed, and further, stirring was continued at 80°C over a period of 2 hours. After the reaction was completed, the reaction product having been cooled down to ordinary temperature was used as a starting material (a-2). The total concentration of magnesium and aluminum in the starting material (a-2) was 0.786 mol/L.
    [0047] [0047] {3) Synthesis of carrier (A-1)
    [0048] [0048] (4) Preparation of solid catalyst component [A] While stirring 1,970 mL of a hexane slurry containing 110 g of the carrier (A-1) at 10°C, 103 mL of a hexane solution of titanium tetrachloride of 1 mol/L and 131 mL of the starting material {(a-2) were simultaneously added to the hexane slurry over a period of 3 hours.
    [0049] [0049] [Production of polyethylene powder] To a Bessel type 300 L polymerization reactor equipped with a stirrer, hexane, ethylene, an o-olefin, hydrogen, the solid catalyst component [A], a cocatalyst component, and STATSAFE 3000 {manufactured by The Associated Octel Company Limited) were continuously fed under the conditions shown in the following Table 1 and Table 2 and the conditions shown in the following examples and comparative examples, thereby producing polyethylene powders as below.
    [0050] [0050] (Example 1: PE-1) The polymerization temperature was kept at 58°C by jacket cooling.
    [0051] [0051] (Example 2) In the homogenous mixing by a Henschel mixer after the drying step, calcium stearate (manufactured by DAINICHI CHEMICAL INDUSTRY CO., LTD., C60) was mixed in such a manner that the concentration became 1,000 ppm based on the polyethylene powder. Regarding other conditions, the same operations as in Example 1 were carried out.
    [0052] [0052] (Example 3) As the a-olefin, l-propene was used. Regarding other conditions, the same operations as in Example 1 were carried out.
    [0053] [0053] (Example 4) As the aliphatic saturated alcohol, ethanol was used. Regarding other conditions, the same operations as in Example 1 were carried out. The polyethylene powder (PE-4) obtained as above was evaluated by the aforesaid methods. The evaluation results are set forth in Table 1.
    [0054] [0054] (Example 5) The polymerization temperature was kept at 77°C. As the a-olefin, 1l-butene was continuously added in such a manner that the 1-butene concentration became 6.4 mol based on the gas phase ethylene concentration. Hydrogen was continuously added in such a manner that the hydrogen concentration became 0.9 mol& based on the gas phase ethylene concentration. Regarding other conditions, the same operations as in Example 1 were carried out. The polyethylene powder (PE-5) obtained as above was evaluated by the aforesaid methods. The evaluation results are set forth in Table 1.
    [0055] [0055] (Example 6) The polymerization temperature was kept at 45°C. As the a-olefin, 1-butene was continuously added in such a manner that the 1-butene concentration became 7.0 mol& based on the gas phase ethylene concentration. The polymerization pressure was kept at 0.5 MPa. Regarding other conditions, the same operations as in Example 1 were carried out.
    [0056] [0056] (Example 7) The polymerization temperature was kept at 73°C. As the a-clefin, l-butene was continuously added in such a manner that the 1-butene concentration became 0.3 mols based on the gas phase ethylene concentration. The polymerization pressure was kept at 0.15 MPa. Regarding other conditions, the same operations as in Example 1 were carried out.
    [0057] [0057] (Example 8) The polymerization temperature was kept at 57°C. Regarding other conditions, the same operations as in Example 7 were carried out.
    [0058] [0058] (Example 9)
    [0059] [0059] (Example 10) By allowing nitrogen to flow in the dryer, the oxygen concentration in the dryer was adjusted to 80 ppm, and feeding of hexane was adjusted in such a manner that the feed rate became 40 L/hour. Regarding other conditions, the same operations as in Example 9 were carried out. The polyethylene powder (PE-10) obtained as above was evaluated by the aforesaid methods. The evaluation results are set forth in Table 1.
    [0060] [0060] (Example 11) By allowing nitrogen to flow in the dryer, the oxygen concentration in the dryer was adjusted to 80 ppm, and the resulting polyethylene powder was homogeneously mixed by a Henschel mixer without adding methanol. Regarding other conditions, the same operations as in
    [0061] [0061] (Comparative Example 1) The polymerization temperature was kept at 83°C. As the a-olefin, l-butene was continuously added in such a manner that the 1-butene concentration became 6.2 mol based on the gas phase ethylene concentration. Hydrogen was continuously added in such a manner that the hydrogen concentration became 0.2 mol based on the gas phase ethylene concentration. Further, feeding of hexane was adjusted in such a manner that the feed rate became 40 L/hour. Furthermore, by allowing nitrogen to flow in the dryer, the oxygen concentration in the dryer was adjusted to 150 ppm. Regarding other conditions, the same operations as in Example 1 were carried out.
    [0062] [0062] (Comparative Example 2) Feeding of hexane was adjusted in such a manner that the feed rate became 55 L/hour, and the resulting polyethylene powder was homogeneously mixed by a Henschel mixer without adding methanol. Regarding other conditions, the same operations as in Comparative Example 1 were carried out. The polyethylene powder (PE-13) obtained as above was evaluated by the aforesaid methods. The evaluation results are set forth in Table 2.
    [0063] [0063] (Comparative Example 3) The oxygen concentration in the dryer was adjusted to 80 ppm, and the resulting polyethylene powder was homogeneously mixed by a Henschel mixer without adding methanol. Regarding other conditions, the same operations as in Comparative Example 1 were carried out. The polyethylene powder (PE-14) obtained as above was evaluated by the aforesaid methods. The evaluation results are set forth in Table 2.
    [0064] [0064] (Comparative Example A4) The resulting polyethylene powder was homogeneously mixed by a Henschel mixer without adding methanol. Regarding other conditions, the same operations as in Comparative Example 1 were carried out. The polyethylene powder (PE-15) obtained as above was evaluated by the aforesaid methods. The evaluation results are set forth in Table 2.
    [0065] [0065] (Comparative Example 5) The polymerization temperature was kept at 75°C. The a-olefin was not added. Addition of the aliphatic saturated alcohol was not carried out. Regarding other conditions, the same operations as in Example 1 were carried out. The polyethylene powder (PE-16) obtained as above was evaluated by the aforesaid methods. The evaluation results are set forth in Table 2.
    [0066] [0066] (Comparative Example 6) The polymerization temperature was kept at 73°C. As the a-olefin, 1-butene was continuously added in such a manner that the l-butene concentration became 0.3 mol based on the gas phase ethylene concentration. Addition of the aliphatic saturated alcohol was not carried out. In the homogenous mixing by a Henschel mixer after the drying step, calcium stearate (manufactured by DAINICHI CHEMICAL INDUSTRY CO., LTD., (C60) was mixed in such a manner that the concentration became 1,000 ppm based on the polyethylene powder. Regarding other conditions, the same operations as in Example 1 were carried out. The polyethylene powder (PE-17) obtained as above was evaluated by the aforesaid methods. The evaluation results are set forth in Table 2.
    [0067] [0067] (Comparative Example 7) The polymerization temperature was kept at 47°C. The a-olefin was not added. The polymerization pressure was kept at 0.4 MPa. Addition of the aliphatic saturated alcohol was not carried out. Regarding other conditions, the same operations as in Example 1 were carried out. The polyethylene powder (PE-18) obtained as above was evaluated by the aforesaid methods. The evaluation results are set forth in Table 2.
    [0068] [0068] (Comparative Example 8) The polymerization temperature was kept at 80°C. As the a-clefin, l-butene was continuously added in such a manner that the 1-butene concentration became 0.15 mol& based on the gas phase ethylene concentration. Hydrogen was continuously added in such a manner that the hydrogen concentration became 0.2 mols based on the gas phase ethylene concentration. The polymerization pressure was kept at 0.15 MPa. Addition of the aliphatic saturated alcohol was not carried out. In the homogenous mixing by a Henschel mixer after the drying step, calcium stearate (manufactured by DAINICHI CHEMICAL INDUSTRY CO., LTD., C60) was mixed in such a manner that the concentration became 500 ppm based on the polyethylene powder. Regarding other conditions, the same operations as in Example 1 were carried out. The polyethylene powder (PE-19) obtained as above was evaluated by the aforesaid methods. The evaluation results are set forth in Table 2.
    [0069] [0069] [Table 1]
    [0070] [0070] [Table 2] Example 1 | Example 2 | Example 3 | Example 4 | Example 5 | Example 6 | Example 7 | Example 8 | eR at | Polymerizaiontemperawerc) | 8 | 8 | 8 | 8 | 7 | 1 | 4&4 | 8 HOI hie Inte | he DE en et 0.3 0.15 | Hydrogen gas phase concentration {mol%) | 02 | 02 | 02 | 02 | o | o | 0.2 Catalyst concentration (mg/L) 12.7 12.7 co 0 0 0 | 0 | 1 0 | 50 | | Oxwgenconeentrationindyer(pem | 10 | 150 | 8 | 150 | 8& [| & WN SRNR 5% NA IAS RA SAS: I 0 0 | 0 | 0 0 | 0 | | Yelownessvi | 82 | 86 | 80 | 78 | 273 | 81 93 63 | WhienessWl | 543 | 51 | 540 | 538 | 939 | ®@5 | ®0 | 655 929 923 939
    [0071] [0071] It has been found that according to the polyethylene powders of Examples 1 to 11, molded articles not only having excellent impact resistance and abrasion resistance but also having excellent transparency and excellent ease of finding stains were obtained. Industrial Applicability
    [0072] [0072] The polyethylene powder of the present invention has industrial applicability as a material for lining materials for hoppers, chutes, and the like because of non-tackiness and low friction coefficient, bearings, gears, roller guide rails, bone substitutes, bone conductive materials and osteoinductive materials, which require self-lubricating properties, low friction coefficient and abrasion resistance, separators for secondary batteries such as lithium-ion secondary batteries and lead storage batteries, and fibers.
    权利要求:
    Claims (1)
    [1]
    Conclusions
    A polyethylene powder comprising, as a constituent unit, an ethylene unit and/or an ethylene unit and an -olefin unit having 3 or more and 8 or less carbon atoms, and having a viscosity average molecular weight of 1,000,000 or more and
    10,000,000 or less, wherein a yellowness YI, a whiteness WI, and a density p of a sheet-formed article under the compression molding conditions described in JIS K6936-2 satisfy the following Expression (1): 0.50 <(- YDxWI/p<2.0... Expression (1)
    The polyethylene powder according to claim 1, wherein the -olefin is 1-propylene or 1-butene, and the content of the a-olefin is 1.0 mol. % or less IS.
    The polyethylene powder according to claim 1 or 2, wherein the polyethylene powder has a bulk density of 0.30 g/ml or more and less than 0.60 g/ml.
    The polyethylene powder according to any one of claims 1 to 3, wherein the total of magnesium, titanium and aluminum element contents as measured by an inductively coupled mass spectrometer (ICP/MS) is 1 ppm or more and 50 ppm or less.
    The polyethylene powder according to any one of claims 1 to 4, wherein in an integral melting curve by differential scanning calorimetry (DSC), a temperature at the time of 30% melting is 120°C or more and 140°C or less, a temperature at the time of 50 % melting is 125 °C or higher and 145 °C or lower, and a temperature at the time of 70 % melting is 130 °C or higher or 150 °C or lower.
    The polyethylene powder according to claim 5, wherein in the integral melting curve by differential scanning calorimetry (DSC), the temperature at the time of 50% melting is 130°C or more or 140°C or less.
    A molded article of the polyethylene powder according to any one of claims 1 to 6.
    The molded article of claim 7, wherein the molded article is a compression molded article.
    The molded article of claim 7, wherein the molded article is an extrusion molded article.
    The molded article of claim 7, wherein the molded article is a stretch molded article 1s.
    The molded article of claim 7, wherein the molded article is a microporous membrane.
    The molded article of claim 7, wherein the molded article is a fiber 1s.
    类似技术:
    公开号 | 公开日 | 专利标题
    US10787563B2|2020-09-29|Bimodal high-density polyethylene resins and compositions with improved properties and methods of making and using the same
    AU2001264132B2|2004-08-05|Injection moulding polymer
    EP2970643B1|2017-11-08|Polymer films having improved heat sealing properties
    RU2727776C1|2020-07-23|Polyethylenes and ethylene copolymers for extrusion blowing film
    JP5830114B2|2015-12-09|Ultra high molecular weight ethylene copolymer powder and molded product
    JP5498296B2|2014-05-21|Ultra high molecular weight polyethylene particles, method for producing the same, and molded body using the same
    US20100092709A1|2010-04-15|Multimodal polyethylene pipe resins and process
    RU2539571C2|2015-01-20|Polymer composition for cross-linked products
    KR20100016232A|2010-02-12|Bimodal polyethylene resins that have high stiffness and high escr
    CN107438631B|2018-06-26|Ultra-high-molecular-weight polyethylene analog copolymer powder and the formed body for having used ultra-high-molecular-weight polyethylene analog copolymer powder
    US20120035339A1|2012-02-09|Ethylene copolymer
    JP6692004B2|2020-05-13|Polyethylene powder, molded body, and microporous membrane
    EP1240214B1|2003-07-02|Ethylene polymerisation
    EP2588506B1|2015-10-07|Self limiting catalyst composition for ethylene polymerization
    NL2027813A|2021-10-20|Polyethylene powder and molded article
    JP5777583B2|2015-09-09|granular ultra-high molecular weight polyethylene and molded body
    JP2018016772A|2018-02-01|Ultrahigh molecular weight polyethylene powder
    JP6684791B2|2020-04-22|Polyethylene homo- or copolymers with improved wear properties
    US20150133575A1|2015-05-14|Process for the polymerisation of ethylene
    EP3929220A1|2021-12-29|Polyethylene powder
    JP6487591B1|2019-03-20|Ultra high molecular weight ethylene polymer powder and molded product using ultra high molecular weight ethylene polymer powder
    JPWO2017163848A1|2018-04-05|Ultra high molecular weight ethylene copolymer powder and molded product using ultra high molecular weight ethylene copolymer powder
    EP2367856B1|2016-03-30|Polyethylene for the production of tight head drums
    JP2020094153A|2020-06-18|Resin composition mainly comprising ethylenic polymer powder, and molded article comprising the same
    同族专利:
    公开号 | 公开日
    JP2021152140A|2021-09-30|
    AT523671A2|2021-10-15|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    DE3127133A1|1981-07-09|1983-01-27|Hoechst Ag, 6000 Frankfurt|METHOD FOR PRODUCING POLYOLEFINS AND THEIR COPOLYMERISATS|
    JP4173444B2|2001-09-06|2008-10-29|三井化学株式会社|Polyethylene resin composition|
    JP2007023171A|2005-07-19|2007-02-01|Mitsui Chemicals Inc|Ultra-high-molecular-weight polyethylene particulate excellent in heat resistance and method for producing the same|
    EP3020736A1|2013-07-10|2016-05-18|Tosoh Corporation|Ultra-high-molecular-weight polyethylene particles and molded body comprising same|
    JP2015157905A|2014-02-24|2015-09-03|旭化成ケミカルズ株式会社|Ultra-high molecular weight ethylene-based copolymer powder, and molding|
    EP3279225A1|2016-03-25|2018-02-07|Asahi Kasei Kabushiki Kaisha|Powder of ultrahigh-molecular-weight ethylene copolymer, and molded object obtained from powder of ultrahigh-molecular-weight ethylene copolymer|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    JP2020052306|2020-03-24|
    [返回顶部]