Resin composition for sliding members, extrusion molded product, automobile parts, and weather strips

Abstract

To provide a resin composition for sliding members excellent in followability and slidability under high load, an extrusion molded body formed of the resin composition for sliding members, vehicle components, and weather strips.SOLUTION: A resin composition for sliding members containing a non-crosslinked olefinic resin component containing propylene units and ethylene units, and polyorganosiloxane, wherein a ratio T1 / T2 of a content ratio T1 (mass%) of the propylene units and a content ratio T2 (mass%) of the ethylene units in the olefinic resin component is 0.30 to 0.70. An extruded body of the resin composition for sliding members. An automobile part comprising the resin composition for sliding members. A weather strip comprising a substrate and a sliding member made of the resin composition for the sliding members.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a resin composition for sliding members, and an extrusion molded article, an automobile part, and a weather strip made from the resin composition for sliding members. [Background technology]

[0002] A weatherstrip attached to the window frame of an automobile door is an automobile part provided to prevent rain, wind, foreign objects, etc. from entering the interior of the vehicle. A weatherstrip has a base part made of a resin such as a propylene-based polymer, and a sliding part provided so as to be laminated on a part of the base part, and is used by sealing the sliding part to the window frame so that it comes into contact with the glass window. Therefore, the sliding member constituting the sliding part is required to have a slidability that does not interfere with the smooth operation of the glass window when it is opened or closed. Generally, known sliding members are made of compositions containing an olefin resin component to which various additives are added.

[0003] As one of the additives for imparting sliding properties to a sliding member, a method of using ultra-high molecular weight polyethylene has been proposed (see Patent Document 1). In addition, when an olefin resin component contains an ethylene resin, a method is also known in which a part of the ethylene resin is crosslinked to form an uneven shape on the surface of a molded article, thereby imparting sliding properties (see Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-204405 A [Patent Document 2] JP 2002-20558 A Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, in order to reduce the noise of vehicles traveling, efforts have been made to press weatherstrips firmly against the window glass to strengthen the sealing properties. In such an operating environment, the sliding members of the weatherstrip are required to have the ability to slide against the glass window even under high loads while still ensuring conformity to the glass to adequately seal the glass window.

[0006] The addition of ultra-high molecular weight polyethylene as a sliding property imparting agent described in Patent Document 1 certainly improves sliding properties, but the ultra-high molecular weight polyethylene is in powder form and is difficult to handle. In addition, Patent Document 1 does not mention conformability, and the technology described in Patent Document 1 does not take into consideration the compatibility of conformability and sliding properties.

[0007] The elastomer composition described in Patent Document 2 does not have sufficient sliding properties under high load. In addition, Patent Document 2 does not mention conformability, and the technology described in Patent Document 2 does not take into consideration the compatibility of conformability and sliding properties.

[0008] An object of the present invention is to solve the above-mentioned problems of the conventional art and to provide a resin composition for sliding members which is excellent in conformity and sliding property under high load, and an extrusion molded article, an automobile part, and a weather strip each made of the resin composition for sliding members. [Means for solving the problem]

[0009] The present inventors have discovered that a resin composition for sliding members containing a non-crosslinked olefin-based resin component containing propylene units and ethylene units and a polyorganosiloxane, in which the mass ratio T1 / T2 of the propylene unit content T1 to the ethylene unit content T2 is 0.30 to 0.70, can realize extrusion molded articles, automobile parts, and weather strips that are excellent in conformity and sliding properties under high load, and have arrived at the present invention.

[0010] That is, the gist of the present invention is as follows.

[0011] [1] A resin composition for a sliding member, comprising a non-crosslinked olefin-based resin component containing propylene units and ethylene units, and a polyorganosiloxane, wherein the ratio T1 / T2 of the propylene unit content T1 (mass%) to the ethylene unit content T2 (mass%) in the olefin-based resin component is 0.30 to 0.70.

[0012] [2] The resin composition for a sliding member according to [1], having a Duro D hardness (ISO 868) of 40 or more and 55 or less.

[0013] [3] The resin composition for a sliding member according to [1] or [2], which has a melt flow rate of 0.5 / 10 min or more and 25 g / 10 min or less, measured at a temperature of 230° C. and a load of 21.2 N according to a method in accordance with JIS K7210.

[0014] [4] The resin composition for a sliding member according to any one of [1] to [3], containing 5 to 15 parts by mass of the polyorganosiloxane per 100 parts by mass of the olefin-based resin component.

[0015] [5] The resin composition for a sliding member according to any one of [1] to [4], wherein the olefin-based resin component contains the following component (A) and component (B): Component (A): Propylene-based polymer Component (B): Ethylene-based polymer

[0016] [6] The resin composition for a sliding member according to [5], wherein, in 100% by mass of the olefin-based resin component, a content of the component (A) is 25 to 60% by mass and a content of the component (B) is 40 to 75% by mass.

[0017] [7] The component (B) has a density of 0.91 to 0.97 g / cm 3 The resin composition for a sliding member according to [5] or [6], comprising a polyethylene of the formula:

[0018] [8] An extrusion molded article of the resin composition for a sliding member according to any one of [1] to [7].

[0019] [9] [8] Automotive parts with extrusion moldings.

[0020]

[10] A weather strip comprising a substrate and a sliding member made of the resin composition for sliding members according to any one of [1] to [7]. Effect of the Invention

[0021] According to the present invention, it is possible to provide a resin composition for sliding members which is excellent in conformity and sliding performance under high load, and an extrusion molded article, an automobile part, and a weather strip made from the resin composition for sliding members.

[0022] The resin composition for sliding members and the extrusion molded product of the present invention are useful as sealing materials for automobiles and sealing materials for building materials, due to their excellent conformability to glass and sliding properties under high load. They are particularly useful as automobile parts such as automobile weather strips. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The present invention will be described in detail below. The present invention is not limited to the following description, and can be modified in any manner without departing from the gist of the present invention. In this specification, when a numerical value or physical property value is enclosed before and after "~", the values ​​before and after are included.

[0024] [Resin composition for sliding members] The resin composition for sliding members of the present invention is a resin composition for sliding members containing a non-crosslinked olefin-based resin component containing propylene units and ethylene units, and polyorganosiloxane, characterized in that the ratio T1 / T2 (hereinafter sometimes simply referred to as "T1 / T2") of the content T1 (mass%) of propylene units in the olefin-based resin component to the content T2 (mass%) of ethylene units is 0.30 to 0.70. This T1 / T2 is preferably 0.35 to 0.70, more preferably 0.35 to 0.68. By setting T1 / T2 in the above range, it is possible to achieve a higher level of both the conformability to a glass window and the sliding properties under high load required for the sliding member.

[0025] [mechanism] Although the details of why the resin composition for a sliding member of the present invention exhibits the above-mentioned effects are not clear, it is presumed to be as follows. Usually, polyorganosiloxane has poor dispersibility in olefin resin components, and when a molded body is molded using a resin composition containing an olefin resin component and polyorganosiloxane, polyorganosiloxane tends to move to the surface side of the molded body, resulting in uneven distribution of polyorganosiloxane on the surface layer of the molded body, and the polyorganosiloxane present on the surface layer during use as a sliding member is discharged from the sliding member to the outside of the system. Therefore, the desired sliding property cannot be obtained as a molded body.

[0026] On the other hand, in a resin composition containing a non-crosslinked olefin resin component containing propylene units and ethylene units and a polyorganosiloxane, if the ratio T1 / T2 of the propylene unit content T1 (mass%) to the ethylene unit content T2 (mass%) is set to 0.30 to 0.70, a co-continuous structure of polyethylene and polypropylene is formed, and a large amount of interfaces where polyorganosiloxane may be unevenly distributed within this structure can be formed. In a molded body using a resin composition having such a co-continuous structure, it is considered that the polyorganosiloxane gradually seeps out of the molded body onto the sliding surface through the interface of the co-continuous structure due to repeated sliding, and excellent sliding properties can be obtained.

[0027] [Physical properties of the resin composition for sliding members] <DuroD hardness> The resin composition for sliding members of the present invention preferably has a DuroD hardness of 40 to 55 measured with reference to the ISO 868 standard. When the DuroD hardness is 40 or more, the sliding property becomes excellent. The DuroD hardness of the resin composition for sliding members of the present invention is preferably 45 or more. On the other hand, when the DuroD hardness is 55 or less, the followability becomes excellent. The DuroD hardness of the resin composition for sliding members of the present invention is preferably 53 or less. In particular, when the DuroD hardness is in the range of 45 to 53, a sliding member having an even better balance of sliding property and followability under high load can be obtained.

[0028] The DuroD hardness of the resin composition for sliding members can be adjusted by controlling the content C1 (mass%) of the resin component having a flexural modulus (JIS K7171) of 1000 MPa or more, for example, 1000 to 2300 MPa, and the content C2 (mass%) of the resin component having a flexural modulus (JIS K7171) of less than 1000 MPa, for example, 20 to 950 MPa, in the resin composition for sliding members. Specifically, by controlling C1 / C2 within the range of 1.5 to 5.0, it becomes easier to obtain the desired hardness. The resin component having a flexural modulus of 1000 MPa or more and the resin component having a flexural modulus of less than 1000 MPa described above can be appropriately selected and used from among component (A) and component (B) described later.

[0029] <Melt flow rate> The resin composition for sliding members of the present invention preferably has a melt flow rate (MFR) of 0.5 g / 10 min or more measured at a measurement temperature of 230°C and a measurement load of 21.2 N with reference to the JIS K7210 standard, more preferably 0.7 g / 10 min or more, and even more preferably 1 g / 10 min or more, from the viewpoint of reducing the load on the molding machine. On the other hand, from the viewpoint of formability during molding, the melt flow rate (MFR) of the resin composition for sliding members of the present invention is preferably 25 g / 10 min or less, more preferably 24 g / 10 min or less, and even more preferably 23 g / 10 min or less.

[0030] [Olefin resin component] The resin composition for a sliding member of the present invention contains a non-crosslinked olefin-based resin component containing propylene units and ethylene units. The resin composition for a sliding member of the present invention preferably contains the olefin-based resin component so that the ratio T1 / T2 of the content T1 (mass%) of the propylene units to the content T2 (mass%) of the ethylene units is 0.30 to 0.70.

[0031] The olefin resin component is not particularly limited as long as it is a non-crosslinked olefin resin component containing propylene units and ethylene units, but from the viewpoint of easy control of the above-mentioned T1 / T2, the olefin resin component according to the present invention preferably contains the following components (A) and (B). Details of these components (A) and (B) will be described later. Component (A): Propylene-based polymer Component (B): Ethylene-based polymer

[0032] The propylene unit content T1 and the ethylene unit content T2 in the olefin resin component containing the above components (A) and (B) can be determined, for example, as follows. In an olefin resin component including, as component (A), component (A-1), component (A-2), .....component (An), and as component (B), component (B-1), component (B-2), .....component (Bn), the content (mass%) of each component in 100 mass% of the olefin resin component, the content (mass%) of the propylene unit in each component, and the content (mass%) of the ethylene unit are Content of component (A-1) in the olefin resin component: M(A-1) mass% Content of component (A-2) in olefin resin component: M(A-2) mass% : : Content of component (An) in olefin resin component: M(An) mass% Content of component (B-1) in the olefin resin component: M(B-1) mass% Content of component (B-2) in the olefin resin component: M(B-2) mass% : : Content of component (Bn) in olefin resin component: M(Bn) mass% Propylene unit content in component (A-1): P(A-1) mass% Propylene unit content in component (A-2): P(A-2) mass% : : Propylene unit content in component (An): P(An) mass% Content of ethylene units in component (A-1): E(A-1) mass% Content of ethylene units in component (A-2): E(A-2) mass% : : Content of ethylene units in component (An): E(An) mass% Propylene unit content in component (B-1): P(B-1) mass% Propylene unit content in component (B-2): P(B-2) mass% : : Propylene unit content in component (Bn): P(Bn) mass% Content of ethylene units in component (B-1): E(B-1) mass% Content of ethylene units in component (B-2): E(B-2) mass% : : Content of ethylene units in component (Bn): E(Bn) mass% In this case, the propylene unit content T1 and the ethylene unit content T2 as the olefin resin components are calculated as follows: T1={M(A-1)×P(A-1)+M(A-2)×P(A-2)+………+M(An)×P(An)+M(B-1)×P(B-1)+M(B-2)×P(B-2)………+M(Bn)×P(Bn)} / 100 T2={M(A-1)×E(A-1)+M(A-2)×E(A-2)+………+M(An)×E(An)+M(B-1)×E(B-1)+M(B-2)×E(B-2)………+M(Bn)×E(Bn)} / 100

[0033] As described above, T1 / T2 in the resin composition for a sliding member of the present invention is 0.30 to 0.70, preferably 0.35 to 0.70, and more preferably 0.35 to 0.68. Therefore, T1 / T2 of the olefin resin component contained in the resin composition for a sliding member of the present invention is preferably 0.30 to 0.70, particularly preferably 0.35 to 0.70, and even more preferably 0.35 to 0.68.

[0034] <Component (A): Propylene-based polymer> The propylene-based polymer of component (A) used in the olefin-based resin component is not particularly limited, and any of a propylene homopolymer, a propylene-based copolymer (a block copolymer or random copolymer of propylene units and other monomer units), etc. can be used. Here, the propylene-based copolymer means one having a propylene unit content of 50% by mass or more.

[0035] When the propylene polymer of component (A) is a propylene copolymer, examples of other monomers copolymerizable with propylene include α-olefins having 2 or 4 to 12 carbon atoms, such as ethylene, 1-butene, 2-methylpropylene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, and 1-decene; cyclic olefins such as cyclopentene, norbornene, and tetracyclo[6,2,11,8,13,6]-4-dodecene; 5-methylene-2-norbornene, Examples of the copolymerizable monomer include, but are not limited to, norbornenes such as 5-ethylidene-2-norbornene, dienes such as 1,4-hexadiene, methyl-1,4-hexadiene, and 7-methyl-1,6-octadiene, and vinyl monomers such as vinyl chloride, vinylidene chloride, acrylonitrile, vinyl acetate, acrylic acid, methacrylic acid, maleic acid, ethyl acrylate, butyl acrylate, methyl methacrylate, maleic anhydride, styrene, methylstyrene, vinyltoluene, and divinylbenzene. These other copolymerizable components may be used alone or in combination of two or more.

[0036] The polypropylene polymer of component (A) preferably has a melt flow rate (MFR; ASTM D 1238, 230°C, load 21.2 N) of 0.3 to 26 g / 10 min, more preferably 0.3 to 15 g / 10 min. By using a polypropylene polymer of component (A) having such an MFR, good moldability and excellent appearance can be ensured.

[0037] The propylene polymer of component (A) has a density (JIS K7112) of 0.85 to 0.92 g / cm 3 It is preferable that the ratio is in the range of 1:1.

[0038] The propylene-based polymer of component (A) can be obtained by a known production method, which is disclosed in detail in, for example, JP-A-50-108385, JP-A-50-126590, JP-A-51-20297, JP-A-51-28189, and JP-A-52-151691, and the techniques described therein can be used in the present invention.

[0039] Moreover, the propylene polymer of component (A) may be a commercially available product. Examples of commercially available products of component (A) include PRIME Polypro (registered trademark) manufactured by Prime Polymer Co., Ltd., Sumitomo Noblen (registered trademark) manufactured by Sumitomo Chemical Co., Ltd., polypropylene block copolymer manufactured by SunAllomer Co., Ltd., Novatec (registered trademark) PP manufactured by Japan Polypropylene Corporation, Tafmer (registered trademark) and WAYMAX (registered trademark) manufactured by Mitsui Chemicals, Inc., Moplen (registered trademark) manufactured by LyondellBasell Corporation, ExxonMobil PP manufactured by ExxonMobil Corporation, Versify (registered trademark) manufactured by Dow Chemical Co., Formolene (registered trademark) manufactured by Formosa Plastics, Borealis PP manufactured by Borealis, SEETEC PP manufactured by LG Chemical Co., Ltd., ASI POLYPROPYLENE manufactured by A. Schulman Co., Ltd., INEOS PP manufactured by INEOS Olefins & Polymers, Braskem PP manufactured by Braskem Co., Ltd., and Samsung PP manufactured by SAMSUNG TOTAL PETROCHEMICALS Co., Ltd. Examples of such polypropylene include Total, Sabic (registered trademark) PP manufactured by Sabic, TOTAL PETROCHEMICALS Polypropylene manufactured by TOTAL PETROCHEMICALS, and YUPLENE (registered trademark) manufactured by SK Corporation.

[0040] The propylene polymer of component (A) may be used alone or in combination of two or more types having different compositions or physical properties.

[0041] [Component (B): Ethylene-based polymer] The ethylene-based polymer of component (B) used in the olefin-based resin component is not particularly limited, and any of ethylene homopolymers, ethylene-based copolymers (block copolymers or random copolymers of ethylene units and other monomer units), etc. can be used. Here, the ethylene copolymer means one having an ethylene unit content of 50% by mass or more.

[0042] When the ethylene-based polymer of component (B) is an ethylene-based copolymer, other monomers copolymerized with ethylene include α-olefins having 3 to 20 carbon atoms such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene, and 1-heptene; non-conjugated polyenes such as 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 1,7-octadiene, 1,9-decanediene, 3,6-dimethyl-1,7-octadiene, 4,5-dimethyl-1,7-octadiene, 5-methyl-1,8-nanodiene, dicyclopentadiene, 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene, 2,5-norbornadiene, and 4-ethylidene-8-methyl-1,7-nanodiene, but are not particularly limited thereto. These other copolymerization components may be used alone or in combination of two or more.

[0043] As the ethylene-based polymer, ethylene homopolymer and ethylene-α-olefin copolymer are preferred.

[0044] Ethylene-based polymers have a density (JIS K6922) of 0.91 to 0.97 g / cm 3 In addition, at least a part of the component (B) preferably has a density of 0.94 to 0.97 g / cm 3 By containing the polyethylene, the resin composition for a sliding member tends to have excellent sliding properties and wear resistance.

[0045] From the viewpoint of density, ethylene polymers can be classified into high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (L-LDPE, LDPE), ethylene plastomers, and ethylene elastomers.

[0046] In this specification, high density polyethylene has a density of 0.94 g / cm 3 or more (0.98g / cm 3 less than 0.93 g / cm 3 More than 0.94g / cm 3Polyethylene polymers with a density of less than 0.91 g / cm 3 More than ~0.93g / cm 3 Polyethylene polymers and ethylene plastomers have a density of less than 0.89 g / cm 3 More than 0.91g / cm 3 Polyethylene polymers and ethylene elastomers have a density of less than 0.89 g / cm 3 Less than (0.85g / cm 3 Among these, high density polyethylene (HDPE) is preferred from the viewpoint of sliding properties.

[0047] In the present invention, the ethylene-based polymer is present in a non-crosslinked state, and therefore, compared with a case in which the ethylene-based polymer is present in a crosslinked state, it is easier to maintain a co-continuous structure, and desired sliding properties can be obtained.

[0048] The ethylene polymer of component (B) preferably has a melt flow rate (MFR; ASTM D1238, 230°C, load 21.2 N) of 0.1 to 13 g / 10 min, more preferably 0.1 to 12 g / 10 min. By using an ethylene polymer of component (B) having such an MFR, it becomes easy to fuse with another member molded from a polypropylene resin material, and it can be suitably used for applications such as sliding members for weather strips.

[0049] The ethylene polymer of component (B) may be a commercially available product, such as the Novatec (registered trademark) series manufactured by Japan Polyethylene Corporation, the Creolex (registered trademark) series manufactured by Asahi Kasei Chemicals Corporation, JSR EP manufactured by JSR Corporation, Mitsui EPT (registered trademark) manufactured by Mitsui Chemicals, Inc., Esprene (registered trademark) manufactured by Sumitomo Chemical Co., Ltd., and Keltan (registered trademark) manufactured by ARLANXEO.

[0050] The ethylene polymer of the component (B) may be used alone or in combination of two or more types having different compositions or physical properties.

[0051] [Polyorganosiloxane] The type of substituent bonded to the siloxane main chain in the molecular structure of the polyorganosiloxane contained in the resin composition for sliding members of the present invention is not particularly limited, but dimethyl silicone (dimethylpolysiloxane), methylphenyl silicone, or alkyl-modified silicone is preferably used.

[0052] In order to thoroughly mix the polyorganosiloxane with other materials constituting the resin composition for sliding members of the present invention, it is preferable to use the polyorganosiloxane as a master batch of a propylene-based polymer or an ethylene-based polymer. As the propylene-based polymer that can be used as a master batch, for example, the propylene-based polymer of the above-mentioned component (A) can be used.

[0053] The polyorganosiloxane preferably has a kinetic viscosity (JIS Z8803, 25°C) of 100,000 cSt or more, with no particular upper limit on this kinetic viscosity. The higher the kinetic viscosity of the polyorganosiloxane, the higher the effect of improving scratch resistance and abrasion resistance, and therefore it is preferable.

[0054] Polyorganosiloxanes are commercially available. Examples of the commercially available products include the "DOW CORNING TORAYTM (registered trademark)" series, the "Versify (registered trademark)" series, and the "DOW CORNINGTM (registered trademark)" series manufactured by DuPont Toray Specialty Materials Co., Ltd., and "X-22-2101" manufactured by Shin-Etsu Chemical Co., Ltd., and the appropriate product can be appropriately selected and used from these.

[0055] The polyorganosiloxanes may be used alone or in any combination and ratio of two or more kinds.

[0056] [Mixing ratio] The resin composition for sliding members of the present invention preferably contains 5 to 15 parts by mass of polyorganosiloxane per 100 parts by mass of the olefin resin component. By setting the lower limit of the polyorganosiloxane content to 5 parts by mass or more, the sliding durability is further improved, the water removal performance is further improved in applications such as sliding members of weather strips, and the generation of abnormal noise during sliding is further reduced. The lower limit of the polyorganosiloxane content is more preferably 8 parts by mass or more. In addition, by setting the upper limit of the polyorganosiloxane content to 15 parts by mass or less, the moldability of the resin composition for sliding members becomes more improved and the occurrence of bleeding tends to be suppressed. The upper limit of the polyorganosiloxane content is more preferably 13 parts by mass or less.

[0057] The content of the propylene polymer of component (A) in 100 parts by mass of the olefin resin component is preferably 25 to 60% by mass, more preferably 25 to 50% by mass, and even more preferably 30 to 50% by mass. The content of the ethylene polymer of component (B) in 100 parts by mass of the olefin resin component is preferably 40 to 75% by mass, more preferably 50 to 75% by mass, and even more preferably 50 to 70% by mass.

[0058] The olefin resin component is preferably composed of 100% by mass of the total of components (A) and (B). The amount of component (A) is more preferably 25 to 60% by mass, and even more preferably 30 to 50% by mass, relative to 100% by mass of the total of components (A) and (B). The amount of component (B) is more preferably 40 to 75% by mass, and even more preferably 50 to 70% by mass, relative to 100% by mass of the total of components (A) and (B).

[0059] The polyorganosiloxane is preferably contained in an amount of 5 to 15 parts by mass, and more preferably 8 to 13 parts by mass, per 100 parts by mass of the total of components (A) and (B).

[0060] By incorporating the respective components in the above-mentioned blending ratios, it becomes easier to achieve higher levels of conformability to the glass window and sliding properties under high load.

[0061] [Other ingredients] The resin composition for a sliding member of the present invention may contain other components (sometimes simply referred to as "other components" in this specification) other than the olefin resin component and the polyorganosiloxane, if necessary, within the scope of not impairing the object of the present invention. Examples of other components include resins and elastomers other than components (A) and (B) (sometimes collectively referred to as "other resins" in this specification) and various additives.

[0062] Other resins that may be contained in the resin composition for sliding members of the present invention include polyolefin resins (excluding those corresponding to the above-mentioned components (A) and (B)), polyester resins, polyamide resins, styrene resins, acrylic resins, polycarbonate resins, polyvinyl chloride resins, and other resins; polyamide-based elastomers such as polyamide-polyol copolymers; polyvinyl chloride-based elastomers and polybutadiene-based elastomers, hydrogenated products thereof, products modified with acid anhydrides or the like to introduce polar functional groups, and products obtained by grafting, randomly and / or block copolymerizing other monomers. The above-mentioned other resins may be contained alone or in combination of two or more kinds.

[0063] Among these, the polyolefin resin may be a homopolymer of an α-olefin having 2 to 4 carbon atoms, such as ethylene, propylene, or 1-butene, or a copolymer having these as the main component. Specifically, these polyolefin resins are not limited to homopolymers such as poly-1-butene, but also include copolymers with other α-olefins having 5 to 20 carbon atoms or vinyl compounds such as vinyl acetate, vinyl chloride, acrylic acid, methacrylic acid, and styrene, so long as they are mainly composed of an α-olefin having 2 to 4 carbon atoms. Furthermore, they may be graft copolymers graft-modified with unsaturated carboxylic acids such as maleic anhydride, maleic acid, and acrylic acid, or derivatives thereof. Furthermore, these polyolefin resins may be mixtures.

[0064] When the resin composition for a sliding member of the present invention contains other resins, the total content of the other resins in the resin composition for a sliding member of the present invention is preferably 30 parts by mass or less, and more preferably 20 parts by mass or less, per 100 parts by mass of the total of the component (A) and the component (B).

[0065]

[0043] Examples of additives that may be contained in the resin composition for a sliding member of the present invention include, in addition to the lubricant used together with the polyorganosiloxane, molding processing aids such as antioxidants and crystal nucleating agents, light stabilizers such as ultraviolet absorbers and hindered amine compounds, hydrolysis resistance improvers, colorants such as pigments and dyes, antistatic agents, conductive agents, flame retardants, reinforcing agents, fillers, plasticizers, release agents, and foaming agents.

[0066] The resin composition for a sliding member of the present invention may contain, as an antioxidant, a dithiocarbamate-based antioxidant, a hindered phenol-based antioxidant, a sulfur-based antioxidant, a phosphorus-based antioxidant, or the like. These antioxidants may be used alone or in combination of two or more.

[0067] When the resin composition for sliding members of the present invention contains an antioxidant, the content of the antioxidant is preferably 0.01 to 5 parts by mass relative to 100 parts by mass of the total of components (A) and (B). A content of the antioxidant of 0.01 parts by mass or more is preferred from the viewpoint of improving the heat deterioration resistance, while a content of 5 parts by mass or less is preferred from the viewpoint of preventing problems such as bleeding and the mechanical strength of the composition.

[0068] In addition, the resin composition for sliding members of the present invention preferably contains a colorant such as carbon black in order to improve design and weather resistance, and in this case, the colorant is preferably blended in an amount of 0.1 to 5 parts by mass, particularly 0.3 to 3 parts by mass, per 100 parts by mass of the total of components (A) and (B). Note that it is preferable to blend a trace amount of a component such as a colorant such as carbon black as a master batch of a resin such as a polyolefin resin in terms of uniform dispersion in the resin composition for sliding members.

[0069] The resin composition for dynamic sliding members of the present invention may contain a filler to improve production stability, dimensional stability, and flame retardancy, and in this case, examples of the filler include glass fiber, hollow glass spheres, carbon fiber, talc, calcium carbonate, mica, clay, potassium titanate fiber, silica, metal soap, titanium dioxide, carbon black, etc. (Carbon black can be used both as a colorant and as a filler.) When a filler is added, the filler is usually used in an amount of 0.1 to 200 parts by mass per 100 parts by mass of the total of component (A) and component (B).

[0070] [Molding of resin composition for sliding member] The resin composition for a sliding member of the present invention can be molded by any of the molding methods including extrusion molding, injection molding, compression molding and blow molding.

[0071] [Extrusion molding] The extrusion molded article of the present invention can be produced by extrusion molding the resin composition for a sliding member of the present invention.

[0072] When the resin composition for sliding member of the present invention is used to form an extrusion molded product integrated with another member, for example, the sliding part of a weather strip having a base part made of a resin such as a propylene-based polymer and a sliding part provided so as to be laminated on a part of the base part, the order of molding the base part and the sliding part may be such that one is molded first and then the other, or they may be molded simultaneously, but a co-extrusion molding method is particularly preferred.

[0073] [Sliding parts] A slide member made of the resin composition for slide members of the present invention is excellent in surface appearance, flexibility, weather resistance, heat resistance, warm water resistance and scratch resistance, and is therefore suitable for composite resin molded products used indoors and outdoors, particularly for automobile exterior parts such as roof moldings, weather strips, window moldings, flush mount moldings, side moldings and glass run channels, automobile interior parts such as protective covers for seat rails, assist grips and shift knobs, entrance door seals, building gaskets such as packing materials, handrails, table edges and desk edges, and is particularly suitable for automotive molding applications such as automotive weather strips. EXAMPLES

[0074] Hereinafter, specific aspects of the present invention will be described in more detail using examples, but the present invention is not limited to the following examples as long as it does not deviate from the gist of the present invention. Note that the values ​​of various manufacturing conditions and evaluation results in the following examples are meant as preferred upper or lower limit values ​​in the embodiments of the present invention, and the preferred range may be a range defined by a combination of the above-mentioned upper or lower limit values ​​and the values ​​of the following examples or values ​​of the examples.

[0075] 〔raw materials〕 The raw materials used in the following examples and comparative examples are as follows.

[0076] [Component (A): Propylene-based polymer] <Propylene homopolymer> A-1: Made by Japan Polypropylene Corporation Product name: Novatec (registered trademark) MFR (230℃, 21.2N): 2.5g / 10min Density (JIS K7112): 0.90g / cm 3 Flexural modulus (JIS K7171): 1400MPa A-2: Made by Japan Polypropylene Corporation Product name: Novatec (registered trademark) MFR (230℃, 21.2N): 11g / 10min Density (JIS K7112): 0.90g / cm 3 Flexural modulus (JIS K7171): 1500MPa A-3: Made by Japan Polypropylene Corporation Product name: Novatec (registered trademark) MFR(230℃, 21.2N): 0.4g / 10min Density (JIS K7112): 0.90g / cm 3 Flexural modulus (JIS K7171): 1950MPa A-4: Made by Japan Polypropylene Corporation Product name: Novatec (registered trademark) MFR (230℃, 21.2N): 40g / 10min Density (JIS K7112): 0.90g / cm 3 Flexural modulus (JIS K7171): 1450MPa

[0077] <Propylene copolymer> A-5: Product name: Versify (registered trademark) manufactured by Dow Chemical Company Propylene-ethylene copolymer Propylene unit content: 80-90% by mass MFR(230℃, 21.2N):25g / 10min Density (JIS K7112): 0.88g / cm 3 Flexural modulus (JIS K7171): 120MPa A-6: Dow Chemical Company, product name: Versify (registered trademark) Propylene-ethylene copolymer Propylene unit content: 80-90% by mass MFR (230℃, 21.2N): 2g / 10min Density (JIS K7112): 0.87g / cm 3 Flexural modulus (JIS K7171): 100MPa A-7: Mitsui Chemicals, Inc. Product name: Toughmer (registered trademark) XM-7070 Propylene-1-butene copolymer Propylene unit content: 65 to 75% by mass MFR(230℃, 21.2N):7g / 10min Flexural modulus (JIS K7171): 200MPa

[0078] [Component (B): Ethylene-based polymer] B-1: Manufactured by Japan Polychem Corporation Product name: Novatec (registered trademark) High Density Polyethylene Density (JIS K6922): 0.96g / cm 3 MFR (230℃, 21.2N): 12g / 10min Flexural modulus (JIS K7171): 1000MPa B-2: Made by Japan Polychem Corporation Product name: Novatec (registered trademark) High Density Polyethylene Density (JIS K6922): 0.96g / cm 3 MFR (230℃, 21.2N): 0.3g / 10min Flexural modulus (JIS K7171): 1600MPa B-3: Asahi Kasei Corporation, product name: Creolex (registered trademark) High Density Polyethylene Density (JIS K6922): 0.97g / cm 3 MFR (230℃, 21.2N): 12g / 10min Flexural modulus (JIS K7171): 1120MPa B-4: Made by Japan Polychem Corporation Product name: Novatec (registered trademark) Low Density Polyethylene Density (JIS K6922): 0.92g / cm 3 MFR (230℃, 21.2N): 12g / 10min Flexural modulus (JIS K7171): 200MPa B-5: Mitsui Chemicals, Inc. Product name: Mitsui EPT (registered trademark) Ethylene Elastomer Ethylene unit content: 66% by mass Propylene unit content: 29% by mass Density (JIS K6922): 0.87g / cm 3 Flexural modulus (JIS K7171): <200MPa

[0079] [Polyorganosiloxane] Manufactured by DuPont Toray Specialty Materials Product name: Versify (registered trademark) MB50-001G2 Dimethylpolysiloxane Masterbatch Dimethylpolysiloxane content: 50% by mass Dynamic viscosity of dimethylpolysiloxane (25℃): 1,000,000 cSt or more

[0080] [Other ingredients] BF300 (filler, manufactured by Bihoku Funka Kogyo Co., Ltd.) Armor Slip CP (lubricant, manufactured by Lion Specialty Chemicals Co., Ltd.) Irganox 1010 (antioxidant, manufactured by BASF Japan Ltd.) TACKIROL 201 (crosslinking agent, manufactured by Taoka Chemical Co., Ltd.) Zinc oxide (crosslinking activator, manufactured by Wako Pure Chemical Industries, Ltd.) Stannous chloride (crosslinking activator, manufactured by Wako Pure Chemical Industries, Ltd.)

[0081] [Evaluation method] The sliding materials in the following Examples and Comparative Examples were evaluated as follows.

[0082] [Pellet production] The ingredients shown in Table 1 were mixed in the ratios shown in Table 1, and the mixture was fed into a synchronous twin-screw extruder (Japan Steel Works "TEX30", L / D=52.5, number of cylinder blocks: 14). The temperature was raised from the upstream to the downstream in the range of 120 to 210°C to perform melt kneading, and the strands discharged from the die were cut with a pelletizer to obtain uniformly shaped pellets made of the resin composition.

[0083] [DuroD hardness] The obtained pellets were injection molded in an in-line screw type injection molding machine (Toshiba Machine Co., Ltd.'s "IS130") under conditions of injection pressure of 50 MPa, cylinder temperature of 220°C, and mold temperature of 40°C to obtain a sheet with a thickness of 2 mm, width of 120 mm, and length of 80 mm. The DuroD hardness of this sheet was measured in accordance with the ISO 868 standard. A material having a DuroD hardness in the range of 40 to 55 is evaluated as having excellent conformability, which is required for a sliding member.

[0084] [MFR] The MFR of the obtained pellets was measured at a load of 21.2 N and a measurement temperature of 230° C. using a melt indexer (model name "L220", manufactured by Tateyama Scientific Industry Co., Ltd.).

[0085] [Kinematic friction coefficient] The obtained pellets were extrusion-molded in a single-screw extruder with the resin temperature set at 180° C. to form a test piece for a sliding material having a width of 25 mm and a thickness of 1 mm. The dynamic friction coefficient of the obtained test piece was measured with a HEIDON friction tester manufactured by Shinto Scientific Co., Ltd., in accordance with the standard ASTM D1894. The test conditions were: counterpart material: glass plate, speed: 100 mm / s, distance: 6 cm, load: 500 g, and measurement environment temperature: 23° C. The smaller this value, the better the sliding properties under high load.

[0086] [Evaluation results] The evaluation results for Examples 1 to 6 and Comparative Examples 1 to 5 are shown in Table 1.

[0087] [Table 1]

[0088] It is clear from Table 1 that the resin composition for a sliding member of the present invention is excellent in conformity and sliding performance under high load. In contrast, in Comparative Examples 1 and 2, T1 / T2 is outside the range of the present invention, the DuroD hardness is not within the range of 40 to 55, and followability is poor. In addition, in Comparative Example 2, the dynamic friction coefficient is large, and the sliding properties are poor. In Comparative Examples 3 to 5, the olefin resin component is crosslinked with a crosslinking agent, so the dynamic friction coefficient is large and the sliding properties under a high load are poor.

Claims

1. A resin composition for a sliding member, comprising a non-crosslinked olefin-based resin component containing a propylene unit and an ethylene unit, and a polyorganosiloxane, wherein a ratio T1 / T2 of a content T1 (mass%) of a propylene unit to a content T2 (mass%) of an ethylene unit in the olefin-based resin component is 0.30 to 0.70; The polyorganosiloxane is contained in an amount of 5 to 15 parts by mass per 100 parts by mass of the olefin-based resin component, The olefin resin component contains the following components (A) and (B): The resin composition for a sliding member, wherein the content of the component (A) is 25 to 60 mass % and the content of the component (B) is 40 to 75 mass % in 100 mass % of the olefin-based resin component. Component (A): Propylene-based polymer Component (B): Ethylene-based polymer

2. 2. The resin composition for a sliding member according to claim 1, which has a Duro D hardness (ISO 868) of 40 or more and 55 or less.

3. 3. The resin composition for a sliding member according to claim 1, which has a melt flow rate of 0.5 / 10 min to 25 g / 10 min, measured at a temperature of 230° C. and a load of 21.2 N according to a method in accordance with JIS K7210.

4. The component (B) has a density of 0.91 to 0.97 g / cm ３ The resin composition for a sliding member according to any one of claims 1 to 3, comprising a polyethylene of the formula:

5. An extrusion molded article of the resin composition for a sliding member according to any one of claims 1 to 4.

6. An automobile part comprising the extrusion molded article according to claim 5.

7. A weather strip comprising a substrate and a sliding member made of the resin composition for sliding members according to any one of claims 1 to 4.

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