Resin composition and molded article

Abstract

To provide: a resin composition capable of forming a molding having a low coefficient of dynamic friction and a reduced comparative abrasion quantity; and a molding obtained from the resin composition.SOLUTION: The resin composition comprises: (A) a polyolefin composition that comprises an ultrahigh molecular weight polyolefin whose limiting viscosity measured in a 135°C decalin solvent is 6-40 dl / g and a low or high molecular weight polyolefin whose limiting viscosity is 0.1-5 dl / g; (B) a polyolefin-silicone block copolymer; and (C) a silicone oil.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a resin composition and a molded article containing the resin composition. [Background technology]

[0002] Among various synthetic resins, ultra-high molecular weight polyethylene, polyamide, fluororesin, and the like have excellent sliding properties and are therefore used as various sliding resin molded products for mechanical parts, electrical parts, and medical applications, and many methods have been proposed for improving the sliding properties of resin molded products.

[0003] As a method for improving sliding properties, a method has been proposed in which ultra-high molecular weight polyethylene, calcium carbonate, and silicone oil are mixed and melted, and then cooled and solidified to obtain a molded product (e.g., Patent Document 1). However, the molded product obtained by this method has a problem in that the oil bleeds out.

[0004] In order to solve such problems, a resin composition containing ultra-high molecular weight polyethylene and a silylated polyolefin has been proposed (for example, Patent Document 2). However, there is a demand for further improvement in sliding properties, that is, a demand for further reduction in the dynamic friction coefficient and specific wear rate when the molded article is formed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2010-202800 A [Patent Document 2] JP 2015-48384 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a resin composition which, when formed into a molded article, can reduce the dynamic friction coefficient and the specific wear rate, and a molded article obtained from the resin composition. [Means for solving the problem]

[0007] As a result of intensive research, the present inventors have found that the above problems can be solved by blending a specific polyolefin composition, a polyolefin-silicone block copolymer, and a silicone oil, and have completed the present invention. Examples of the aspects of the present invention include the following [1] to [4].

[0008] [1] A resin composition comprising: (A) an ultra-high molecular weight polyolefin having an intrinsic viscosity of 6 to 40 dl / g measured in decalin solvent at 135°C, and a low-molecular weight or high-molecular weight polyolefin having an intrinsic viscosity of 0.1 to 5 dl / g; (B) a polyolefin-silicone block copolymer; and (C) a silicone oil.

[0009] [2] The resin composition according to item [1], wherein the content ratio (mass ratio) of the components (A), (B) and (C) [(A) / (B) / (C)] is 60.0 to 99.45 / 0.5 to 30.0 / 0.05 to 10.0.

[0010] [3] A molded article comprising the resin composition according to item [1] or [2]. [4] The molded article according to item [3], which is a coating material or a sliding material. Effect of the Invention

[0011] According to the present invention, there are provided a resin composition which, when formed into a molded article, can reduce the dynamic friction coefficient and the specific wear rate, and a molded article obtained from the resin composition. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention will be described in detail below. In this specification, the expression "X to Y" in the description of a numerical range means from X to Y unless otherwise specified. For example, "6 to 40 dl / g" means "from 6 dl / g to 40 dl / g".

[0013] The resin composition according to the present invention comprises: (A) a polyolefin composition comprising an ultra-high molecular weight polyolefin having an intrinsic viscosity of 6 to 40 dl / g measured in decalin solvent at 135°C, and a low-molecular weight to high-molecular weight polyolefin having an intrinsic viscosity of 0.1 to 5 dl / g; (B) a polyolefin-silicone block copolymer, and (C) Silicone oil The present invention is characterized by comprising:

[0014] [Polyolefin composition (A)] The polyolefin composition (A) used in the present invention contains an ultra-high molecular weight polyolefin and a low- to high-molecular weight polyolefin.

[0015] <Ultra-high molecular weight polyolefin> The ultra-high molecular weight polyolefin may be, for example, a homopolymer or copolymer of an α-olefin such as ethylene, propylene, 1-butene, isobutene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, or 1-icosene. In the present invention, an ethylene homopolymer and a copolymer mainly composed of ethylene and another α-olefin are preferred.

[0016] The ultra-high molecular weight polyolefin has an intrinsic viscosity [η] measured in decalin solvent at 135° C. of 6 to 40 dl / g, preferably 10 to 40 dl / g, and more preferably 25 to 35 dl / g. The density of the above ultra-high molecular weight polyolefin (D: measured according to ASTM D1505) is 0.920 g / cm 3 More than 0.935g / cm 3 It is preferable that it is less than 1000 .mu.m.

[0017] <Low to high molecular weight polyolefin> The low-molecular-weight or high-molecular-weight polyolefin is not particularly limited as long as it is a polyolefin having an intrinsic viscosity of 0.1 to 5 dl / g, and is usually composed of the above-mentioned α-olefin homopolymer or copolymer, as with the above-mentioned ultra-high molecular weight polyolefin. In the present invention, ethylene homopolymer and copolymers containing ethylene as a main component, which are composed of ethylene and another α-olefin, are preferred.

[0018] The intrinsic viscosity [η] of the low-molecular-weight or high-molecular-weight polyolefin measured in decalin solvent at 135° C. is 0.1 to 5 dl / g, preferably 0.1 to 2 dl / g. The difference between the intrinsic viscosity of the ultra-high molecular weight polyolefin and the intrinsic viscosity of the low-molecular-weight or high-molecular-weight polyolefin is preferably 23 to 39 dl / g, more preferably 23 to 37 dl / g. The density of the low molecular weight to high molecular weight polyolefin is 0.935 g / cm 3 More preferably, it is equal to or greater than this.

[0019] <Composition and properties of polyolefin composition (A)> The content of the ultra-high molecular weight polyolefin in the polyolefin composition (A) is preferably in the range of 5 to 45 mass%, more preferably 10 to 30 mass%, and even more preferably 10 to 25 mass%, based on the total amount of the ultra-high molecular weight polyolefin and the low molecular weight or high molecular weight polyolefin. The intrinsic viscosity of the polyolefin composition (A) is preferably in the range of 5 to 15 dl / g, more preferably 3 to 10 dl / g, and further preferably 4 to 6 dl / g.

[0020] <Method for preparing polyolefin composition (A)> The polyolefin composition (A) is prepared by mixing an ultra-high molecular weight polyolefin and a low- or high-molecular weight polyolefin by a known method.

[0021] In addition, the polyolefin composition (A) can be prepared by carrying out multi-stage polymerization using a specific Ziegler type catalyst during olefin polymerization to produce a mixture containing ultra-high molecular weight polyolefins and low to high molecular weight polyolefins in a specific ratio.

[0022] As a method for preparing a polyolefin composition (A) containing an ultra-high molecular weight polyolefin and a low to high molecular weight polyolefin by multi-stage polymerization, a method of multi-stage polymerization of olefins in the presence of a Ziegler type catalyst formed from a highly active solid titanium catalyst component (a) containing magnesium, titanium and a halogen as essential components and an organoaluminum compound catalyst component (b) is adopted.

[0023] Specific examples of Ziegler catalysts that can be used in the preparation of the polyolefin composition (A) include the Ziegler catalysts described in JP-A-2001-279093, which also describes a method for producing such a Ziegler catalyst.

[0024] [Polyolefin-silicone block copolymer (B)] The polyolefin / silicone block copolymer (B) used in the present invention may, for example, be A block copolymer in which a polyolefin chain and a silicone chain are bonded in that order. A block copolymer in which (polyolefin chain)-(silicone chain)-(polyolefin chain) are bonded in this order. The following can be mentioned. A polyolefin may be grafted onto the silicone portion of the block copolymer.

[0025] The polyolefin chain may be, for example, a polymer chain containing a structural unit derived from an olefin having 2 to 50 carbon atoms, preferably 2 to 20 carbon atoms. The polyolefin-silicone block copolymer is preferably one having a structure represented by the following formula (1).

[0026] [ka]

[0027] In the above formula (1), A 1 , A 2 and A 3 are each independently a polyolefin chain or a hydrocarbon group having 1 to 20 carbon atoms. R is a hydrocarbon group having 1 to 20 carbon atoms. Each R may be the same or different. m is an integer of 1 to 10,000. 3 If there are multiple A 3 may be the same or different. A 1 and A 2 At least one of these represents a polyolefin chain. Above A 1 , A 2 and A 3 The polyolefin chain in the formula (I) is a polymer chain containing a structural unit derived from an olefin having, for example, 2 to 50 carbon atoms, preferably 2 to 20 carbon atoms.

[0028] Specific examples of the olefin having 2 to 50 carbon atoms include ethylene and α-olefins having 3 to 50 carbon atoms (propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 3,4-dimethyl-1-pentene, 4-methyl-1-hexene, 3-ethyl-1-pentene, 3-ethyl-4-methyl-1-pentene, 3,4-dimethyl-1-hexene, 4-methyl-1-heptene, 3,4-dimethyl-1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, vinylcyclohexane, etc.). Among these, ethylene and α-olefins having 3 to 12 carbon atoms are preferred, ethylene and α-olefins having 3 to 8 carbon atoms are more preferred, and ethylene is particularly preferred. The polyolefin chain may be a homopolymer chain or a copolymer chain.

[0029] Among the above, a polymer chain composed only of an olefin having 2 to 50 carbon atoms selected from ethylene and an α-olefin having 3 to 50 carbon atoms is preferred, and an ethylene homopolymer chain, a propylene homopolymer chain, or a copolymer chain of ethylene and an α-olefin having 3 to 20 carbon atoms is more preferred. In the copolymer chain of ethylene and an α-olefin having 3 to 20 carbon atoms, when all constitutional units are taken as 100 mol %, the structural unit derived from an α-olefin having 3 to 20 carbon atoms can be, for example, more than 0 mol % and not more than 20 mol %, or can also be more than 0 mol % and not more than 10 mol %.

[0030] The polyolefin chain may also contain structural units derived from other olefins, if desired. Examples of other olefins include olefins containing internal double bonds such as cis-2-butene, vinylidene compounds such as isobutene, arylvinyl compounds such as styrene, arylvinylidene compounds such as α-methylstyrene, functional group-substituted vinylidene compounds such as methyl methacrylate, aliphatic cyclic olefins containing internal double bonds such as 5-methyl-2-norbornene, tetracyclododecene, cyclopentadiene, and dicyclopentadiene, cyclic olefins containing aromatic rings such as indene, and linear or cyclic polyenes such as butadiene, isoprene, ethylidene norbornene, and vinyl norbornene.

[0031] The content of structural units derived from other olefins is preferably from 0 to 10 mol %, and more preferably from 0 to 5 mol %, when all structural units constituting the polyolefin chain are taken as 100 mol %. The polyolefin chain preferably has a number average molecular weight, determined by the GPC method described below, of 100 or more and 500,000 or less, more preferably 200 or more and 100,000 or less, even more preferably 500 or more and 50,000 or less, and even more preferably 700 or more and 10,000 or less. The polyolefin chain preferably has a molecular weight distribution (Mw / Mn) in the range of 1.1 to 3.0, as determined by the GPC method described below.

[0032] GPC measurements are performed at 140°C using orthodichlorobenzene as a solvent, and analytical values ​​(weight average molecular weight (Mw), number average molecular weight (Mn) and Mw / Mn) can be obtained in terms of polyethylene. The measurements can be performed under the following conditions. The molecular weight can be calculated based on the following conversion method using a calibration curve prepared using commercially available monodisperse standard polystyrene. Apparatus: Gel permeation chromatograph Alliance GPC2000 (Waters) Solvent: o-dichlorobenzene Column: TSKgel column (Tosoh Corporation) x 4 Flow rate: 1.0ml / min Sample: 0.15mg / mL Lo-dichlorobenzene solution Temperature: 140℃ Molecular weight conversion: PS conversion / general calibration method

[0033] For general-purpose calibration calculations, the coefficients of the Mark-Houwink viscosity equation shown below can be used. Polystyrene (PS) coefficient: KPS = 1.38 x 10 -4 ,aPS=0.70 Coefficient of polyethylene (PE): KPE = 5.06 x 10 -4 ,aPE=0.70

[0034] Above A 1 , A 2 , A 3 In addition, in R, examples of the hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, include an alkyl group, an arylalkyl group, an alkenyl group, and an aryl group.

[0035] Examples of the alkyl group include linear or branched alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, hexyl, 2-ethylhexyl, octyl, decyl, and octadecyl; and cycloalkyl groups such as cyclopentyl, cyclohexyl, and norbornyl. Examples of the arylalkyl group include benzyl, phenylethyl, and phenylpropyl. Examples of the alkenyl group include vinyl, propenyl, and cyclohexenyl. Examples of the aryl group include phenyl, tolyl, dimethylphenyl, trimethylphenyl, ethylphenyl, propylphenyl, and naphthyl.

[0036] In the above formula (1), m is an integer of 1 to 10,000. m is preferably 5 or more, and more preferably 10 or more. Moreover, m is preferably 1,000 or less, more preferably 300 or less, and more preferably 50 or less. Above A 1 and A 2may both be polyolefin chains, or either one of them may be a polyolefin chain.

[0037] In the above formula (1), m is 2 or more, and A 3 At least one of the other A 3 When the unit order is different from the above, multiple types of the following units are present, but there is no particular restriction on the order in which they are arranged, and they may be arranged in a block or random order.

[0038] [ka]

[0039] As the above formula (1), a structure represented by the following (1A) or (1B) is preferable, and among them, (1A) is more preferable. (1A) In the above formula (1), A 1 and A 2 is a polyolefin chain, and A 3 is a hydrocarbon group having 1 to 20 carbon atoms. (1B) In the above formula (1), A 1 and A 2 one of which is a polyolefin chain and the other is a hydrocarbon group having 1 to 20 carbon atoms; 3 is a hydrocarbon group having 1 to 20 carbon atoms.

[0040] In the polyolefin-silicone block copolymer, the silicone chain / polyolefin chain (weight ratio) is not particularly limited, but is, for example, preferably 5 / 95 to 99 / 1, and more preferably 10 / 90 to 95 / 5.

[0041] The method for producing the polyolefin-silicone block copolymer is not particularly limited, but examples thereof include the methods described in paragraphs 0089 to 0145 and paragraphs 0196 to 0207 of WO2012 / 098865.

[0042] [Silicone oil (C)] The silicone oil (C) used in the present invention is, for example, a silicone oil represented by the general formula: RSiO-(RSiO) n Examples of the compound include a compound represented by the formula -SiR3 (wherein R represents an alkyl group which may be the same or different, and is preferably an alkyl group having 1 to 6 carbon atoms, and n represents the number of repeating units).

[0043] Specific examples of the silicone oil (C) include at least one selected from the group consisting of dimethylsilicone oil, methylphenylsilicone oil, alkyl-modified silicone oil, fluorosilicone oil, polyether-modified silicone oil, and fatty acid ester-modified silicone oil. The kinetic viscosity of the silicone oil (C) at 25° C. is preferably 5.0 to 10,000 mm 2 / s, more preferably 10 to 1,000 mm 2 / s.

[0044] [Resin composition] The content ratio (mass ratio) of the above components (A), (B) and (C) in the resin composition of the present invention [(A) / (B) / (C)] is preferably 60.0-99.45 / 0.5-30.0 / 0.05-10.0, more preferably 72.0-98.9 / 1.0-20.0 / 0.1-8.0, and even more preferably 85.0-97.5 / 2.0-10.0 / 0.5-5.0.

[0045] The above description "60.0 to 99.45 / 0.5 to 30.0 / 0.05 to 10.0" means that, when the total of the contents (mass) of the above components (A), (B), and (C) is taken as 100, the content (mass) of the above component (A) is 60.0 to 99.45, the content (mass) of the above component (B) is 0.5 to 30.0, and the content (mass) of the above component (C) is 0.05 to 10.0.

[0046] When the entire resin composition of the present invention is taken as 100% by mass, the total content of the above components (A), (B) and (C) is preferably 60 to 100% by mass. The resin composition of the present invention may be composed only of the above components (A), (B) and (C), but may further contain other resins, additives, etc., as desired, within the scope of not impairing the object of the present invention.

[0047] Examples of additives include plasticizers, UV stabilizers, color inhibitors, matting agents, deodorants, flame retardants, weather resistance agents, antistatic agents, thread friction reducers, slip agents, release agents, antioxidants, ion exchange agents, and color pigments. If necessary, other oils can be added, such as edible oils and glycerin fatty acid esters.

[0048] The resin composition of the present invention can be prepared by melt-kneading the above-mentioned components using a known method, for example, a single-screw or twin-screw extruder, a kneader, a Henschel mixer, a Banbury mixer, a tumbler mixer, etc., and can also be pelletized as necessary for use. Alternatively, a masterbatch having a high concentration of polyolefin-silicone block copolymer can be prepared, and the masterbatch can be diluted with polyolefin for use.

[0049] [Molded body] The molded article of the present invention contains the above-mentioned resin composition of the present invention. The molded article of the present invention can be molded into a container, tray, sheet, belt, rod, film, or various molded article coating, etc., by a conventionally known method, specifically, for example, injection molding, profile extrusion molding, coextrusion molding, pipe molding, tube molding, coating molding of heterogeneous molded articles, injection blow molding, direct blow molding, T-die sheet or film molding, inflation film molding, press molding, etc., using the resin composition of the present invention. In particular, when the resin composition of the present invention is used to coat a resin molded article, it is preferable to use a coextrusion molding method.

[0050] The molded articles obtained by the above molding method can be widely used in conventionally known polyolefin applications, but since they have an excellent balance of properties such as abrasion resistance, self-lubrication, and thin-wall molding, they are used in applications requiring these properties, such as metal coatings (laminations) for steel pipes, electric wires, and automobile sliding door rails, pressure-resistant rubber hoses, automobile door gaskets, clean room door gaskets, automobile glass run channels, automobile weather strips, and other various thermoplastic resin and rubber coatings (laminations), linings for hoppers and chutes, and sliding materials such as gears, bearings, rollers, tape reels, various guide rails and elevator rail guides, and various protective liner materials. EXAMPLES

[0051] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0052] [Components used in the Examples and Comparative Examples] <Polyolefin Composition (A)> Intrinsic viscosity is 14 dl / g, density is 940 kg / m 3 The ultra-high molecular weight polyethylene has a limiting viscosity of 1.0 dl / g and a density of 970 kg / m 3 A polyolefin composition was used, which was composed of 84.2 mass % of a polyethylene resin having the formula (I) and a polyethylene resin having the formula (II). The intrinsic viscosity of this polyolefin composition was 5 dl / g. The intrinsic viscosity and density were measured by the following methods.

[0053] (Intrinsic viscosity [η]) The intrinsic viscosity [η] was measured at 135°C using decalin solvent. That is, the granulated pellets (about 20 mg) of the sample were dissolved in decalin solvent (15 mL), and the specific viscosity ηsp was measured in an oil bath at 135°C. After diluting this decalin solution with additional decalin solvent (5 mL), the specific viscosity ηsp was measured in the same manner as above. This dilution operation was repeated two more times, and the value of ηsp / C when the concentration (C) of the sample was extrapolated to 0 was taken as the intrinsic viscosity [η] of the olefin polymer. Intrinsic viscosity [η]=lim(ηsp / C) (C→0)

[0054] (density) Density was measured according to ASTM D1505.

[0055] <Polyolefin-silicone block copolymer (B)> A polyolefin-silicone block copolymer obtained in the same manner as in Synthesis Example 2 of JP2018-123175A was used.

[0056] <Silicone oil (C)> "BY27-002" (dimethyl silicone oil) manufactured by DuPont Toray Specialty Materials Co., Ltd. was used.

[0057] [Examples 1 to 3 and Comparative Examples 1 to 4] According to the compounding amounts shown in Table 1 below, resin compositions were obtained by melt-kneading each component at 230°C using a twin-screw extruder (Toshiba Machine Co., Ltd. "TEM26-SS"). Using each of the obtained resin compositions, flat plate test pieces of 30 mm length x 30 mm width x 3 mm thickness were prepared by injection molding, and the following physical property evaluations were performed. The results are shown in Table 1 below.

[0058] <Dynamic friction coefficient / specific wear rate> The dynamic friction coefficient of the test piece was measured using a Matsubara friction and wear tester in accordance with JIS K7218 "Sliding abrasion test method A for plastics." The test conditions were as follows: Compatible material: carbon steel (S45C), speed: 50cm / sec, distance: 3km, load: 15kg, measurement environment temperature: 23℃. The specific wear rate was calculated from the weight, density and load of the test piece before and after the test.

[0059] [Table 1]

Claims

1. (A) a polyolefin composition comprising an ultra-high molecular weight polyolefin having an intrinsic viscosity of 6 to 40 dl / g measured in decalin solvent at 135° C., and a low-molecular weight to high-molecular weight polyolefin having an intrinsic viscosity of 0.1 to 5 dl / g; (B) a polyolefin-silicone block copolymer, and (C) Silicone oil Including, A resin composition characterized in that the content ratio (mass ratio) of the components (A), (B) and (C) [(A) / (B) / (C)] is 60.0 to 99.45 / 0.5 to 30.0 / 0.05 to 10.

0.

2. A molded article comprising the resin composition according to claim 1.

3. 3. The molded article according to claim 2, which is a coating material or a sliding material.

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