Crosslinked thermoplastic elastomer composition

Abstract

To provide a crosslinked thermoplastic elastomer composition that can form a composite molding having excellent fusion durability and slidability.SOLUTION: A crosslinked thermoplastic elastomer composition contains the following components (A), (B), (C) and (D), wherein, a tensile stress at break is 7 MPa or more and less than 15 MPa when measured at 23°C in accordance with a measurement method of tensile stress at break specified in ISO37 Type1A (test speed 500 mm / min). The component (A): a styrenic elastomer, component (B): an unmodified polypropylene, component (C): a modified polypropylene modified with methacrylic acid and / or a derivative thereof, and component (D): a lubricant.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a crosslinked thermoplastic elastomer composition, a joining member made of the crosslinked thermoplastic elastomer composition, a composite molded article for automobiles using the joining member, and a corner material for automobiles. [Background technology]

[0002] Thermoplastic elastomer compositions obtained by dynamic heat treatment after melt-kneading polypropylene resin and styrene-butadiene block copolymer exhibit rubber-like soft material properties while eliminating the need for a vulcanization process and possessing moldability similar to thermoplastic resins. For this reason, such thermoplastic elastomer compositions have attracted attention from the standpoint of rationalizing the manufacturing process and recyclability, and are widely used in fields such as automotive parts, home appliances, medical equipment parts, electric wires, and general merchandise. In particular, these thermoplastic elastomer compositions have been widely used as sealing materials for automobiles and building materials.

[0003] The components used in automotive and building sealants have complex structures, and the desired components are manufactured by joining these components together. Instead of using liquid or paste-like adhesives to join the components, a technique is known in which they are joined via connecting members.

[0004] For example, a technique is known in which a joining member made of a specific thermoplastic elastomer composition is used to join members made of dynamically crosslinked thermoplastic elastomers (see Patent Documents 1 and 2). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2019-131722 [Patent Document 2] Japanese Patent Publication No. 2020-125442 [Overview of the project] [Problems that the invention aims to solve]

[0006] Composite molded articles used as sealing materials for window frames of automobiles and the like are obtained by fusing a joining member and a joined member at the joint surface. To prevent abnormal noise and sagging caused by repeated raising and lowering of windows, there is a need for technology that achieves a high level of both fusion durability and sliding properties in these composite molded articles.

[0007] The joint members made of thermoplastic elastomer compositions described in Patent Documents 1 and 2 have good sliding properties and fusion properties with the members to be joined. However, when the joint member is bent starting from the interface between the joint member and the members to be joined at the fused portion, it easily peels off from that interface, indicating that there was room for improvement in the fusion durability at the fused portion between the joint member and the members to be joined.

[0008] Thus, currently, there are no thermoplastic elastomer compositions that achieve a high level of both fusion durability and sliding properties, and that are excellent as joining members for automotive composite molded products.

[0009] The object of the present invention is to solve the problems of the prior art described above and to provide a crosslinked thermoplastic elastomer composition capable of forming a composite molded article with excellent fusion durability and sliding properties, a joining member made of this crosslinked thermoplastic elastomer composition, a composite molded article for automobiles equipped with this joining member, and a corner material for automobiles. [Means for solving the problem]

[0010] The inventors have discovered a novel finding, previously unknown, that a crosslinked thermoplastic elastomer composition obtained by melt-kneading a material composition containing component (A): styrene-based elastomer, component (B): unmodified polypropylene, component (C): modified polypropylene modified with (meth)acrylic acid and / or its derivatives, and component (D): lubricant, in the presence of component (f): crosslinking agent, or a crosslinked thermoplastic elastomer composition containing the above components (A), (B), (C), and (D), and having a tensile stress at break measured at 23°C in accordance with the ISO 37 Type 1A (test speed 500 mm / min) method for measuring tensile stress at break of 7 MPa or more and less than 15 MPa, can achieve a high level of sliding properties in addition to excellent fusion durability, thus solving the above problems and completing the present invention.

[0011] In other words, the gist of this invention is as follows:

[0012] [1] A crosslinked thermoplastic elastomer composition obtained by melt-kneading a material composition containing the following components (A), (B), (C), and (D) in the presence of the following component (f). Ingredient (A): Styrene elastomer Component (B): Unmodified polypropylene Component (C): Modified polypropylene modified with (meth)acrylic acid and / or its derivatives Ingredient (D): Lubricant Ingredient (f): Crosslinking agent

[0013] [2] A crosslinked thermoplastic elastomer composition comprising the following components (A), (B), (C), and (D), wherein the tensile stress at break measured at 23°C in accordance with the ISO 37 Type 1A (test speed 500 mm / min) method for measuring tensile stress at break is 7 MPa or more and less than 15 MPa. Ingredient (A): Styrene elastomer Component (B): Unmodified polypropylene Component (C): Modified polypropylene modified with (meth)acrylic acid and / or its derivatives Ingredient (D): Lubricant

[0014] [3] The crosslinked thermoplastic elastomer composition according to [1] or [2], wherein the melt flow rate (MFR) of the unmodified polypropylene of the component (B) is 1 g / 10 min or more and 60 g / 10 min or less, measured at a measurement temperature of 230 °C and a measurement load of 21.2 N in accordance with JIS K7210 (1999).

[0015] [4] A joining member comprising the crosslinked thermoplastic elastomer composition according to any one of [1] to [3].

[0016] [5] An automotive composite molded body provided with the joining member according to [4].

[0017] [6] An automotive corner material using the composite molded body according to [5].

Advantages of the Invention

[0021] [Cross-linked thermoplastic elastomer composition] The crosslinked thermoplastic elastomer composition of the present invention is a crosslinked thermoplastic elastomer composition obtained by melt-kneading a material composition containing at least the following components (A), (B), (C), and (D) in the presence of component (f). Ingredient (A): Styrene elastomer Component (B): Unmodified polypropylene Component (C): Modified polypropylene modified with (meth)acrylic acid and / or its derivatives Ingredient (D): Lubricant Ingredient (f): Crosslinking agent

[0022] The crosslinked thermoplastic elastomer composition of the present invention also comprises the following components (A), (B), (C), and (D), and is a crosslinked thermoplastic elastomer composition in which the tensile stress at break measured at 23°C in accordance with the ISO 37 Type 1A (test speed 500 mm / min) method for measuring tensile stress at break is 7 MPa or more and less than 15 MPa. Ingredient (A): Styrene elastomer Component (B): Unmodified polypropylene Component (C): Modified polypropylene modified with (meth)acrylic acid and / or its derivatives Ingredient (D): Lubricant The tensile stress at break is related to the crosslinking state of the thermoplastic elastomer composition. The tensile stress at break tends to be higher in non-crosslinked thermoplastic elastomer compositions and lower in crosslinked thermoplastic elastomer compositions. The reason why the tensile stress at break tends to be lower in crosslinked thermoplastic elastomer compositions is that the crosslinked portions in the composition do not stretch, and stress is more concentrated in the non-crosslinked portions, which promotes slippage between molecular chains and makes it easier to fracture through void formation. In other words, the interface between the rubber and resin portions is weaker in crosslinked thermoplastic elastomer compositions compared to non-crosslinked thermoplastic elastomers, which tends to result in a lower stress at break.

[0023] [mechanism] The crosslinked thermoplastic elastomer composition of the present invention exhibits excellent fusion durability and good sliding properties.

[0024] The detailed reasons why the crosslinked thermoplastic elastomer composition of the present invention exhibits such effects are not entirely clear, but they are thought to be as follows. The crosslinked thermoplastic elastomer composition of the present invention is thought to have improved fusion durability because the presence of polar groups derived from (meth)acrylic acid and / or its derivatives of component (C) on the surface of the crosslinked thermoplastic elastomer composition promotes molecular entanglement at the bonding surface with the members to be joined during thermal fusion. If the sole purpose is to improve sliding properties, then a larger amount of lubricant component (D) can be added, but this would worsen the fusion durability. The crosslinked thermoplastic elastomer composition of the present invention is considered to have excellent sliding properties because, since component (B) and component (C) both have a common polypropylene main chain, component (B) and component (C) are compatible with each other, and high surface smoothness derived from the polypropylene portion of component (B) and component (C) is maintained. The crosslinked thermoplastic elastomer composition of the present invention is preferable because it easily exhibits the effects of the above mechanism by controlling the structure to a domain matrix structure in which a domain portion of component (A) is located in the matrix portion containing component (B), component (C), and component (D).

[0025] [Ingredients (A)] The component (A) used in this invention is a styrene-based elastomer.

[0026] As styrene-based elastomers, block copolymers having at least two polymer block P (hereinafter sometimes simply referred to as "block P") mainly composed of aromatic vinyl compound units and at least one polymer block Q (hereinafter sometimes simply referred to as "block Q") mainly composed of conjugated diene compound units, and / or hydrogenated versions of said block copolymers are preferred. Hereinafter, these block copolymers and / or their hydrogenated versions may be referred to as "(hydrogenated) block copolymers".

[0027] Here, "primarily" means that the target monomer unit is present in the target polymer block at a concentration of 50 mol% or more.

[0028] The aromatic vinyl compounds constituting block P are not particularly limited, and examples include styrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylethylene, N,N-dimethyl-p-aminoethylstyrene, and N,N-diethyl-p-aminoethylstyrene. Among these, styrene, α-methylstyrene, and p-methylstyrene are preferred from the viewpoint of availability and productivity. Styrene is more preferred.

[0029] Block P may consist of one type of aromatic vinyl compound unit, or it may consist of two or more types of aromatic vinyl compound units. Block P may also contain monomer units other than vinyl aromatic compound units.

[0030] The conjugated diene compound constituting block Q is a diolefin having one pair of conjugated double bonds. Examples of conjugated diene compounds include, but are not limited to, 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, and 1,3-hexadiene. Among these, 1,3-butadiene and isoprene are preferred from the viewpoint of productivity. More preferably, 1,3-butadiene is used.

[0031] Block Q may consist of one type of conjugated diene compound unit, or it may consist of two or more types of conjugated diene compound units. Block Q may also contain monomer units other than conjugated diene compound units.

[0032] The mass percentage of block P, which mainly consists of aromatic vinyl compound units, in the block copolymer of component (A) is not limited, but is preferably 5% by mass or more, more preferably 10% by mass or more, on the other hand, is preferably 55% by mass or less, more preferably 50% by mass or less, and even more preferably 45% by mass or less.

[0033] The chemical structure of the block copolymer of component (A) may be linear, branched, radial, or any other, but it is preferably a block copolymer represented by the following formula (1) or (2), and more preferably the structure of the following formula (1) from the viewpoint of improving mechanical strength.

[0034] P-(QP)m (1) (PQ)n (2) In the formula, P represents block P, Q represents block Q, m represents an integer from 1 to 5, and n represents an integer from 2 to 5. If there are multiple blocks P and multiple blocks Q, the monomer units contained within them may be the same or different.

[0035] In equation (1) or (2), larger values ​​of m and n are preferable in terms of lowering the order-to-disorder transition temperature of the rubbery polymer, but smaller values ​​are preferable in terms of ease of manufacture and cost.

[0036] Component (A) is preferably a block copolymer represented by formula (1) from the viewpoint of the rubber elasticity of the composition, more preferably a block copolymer represented by formula (1) where m is 3 or less, even more preferably a block copolymer represented by formula (1) where m is 2 or less, and particularly preferably a block copolymer represented by formula (1) where m is 1.

[0037] Component (A) used in the present invention may be a hydrogenated block copolymer having block P and block Q. In this case, it is preferably a hydrogenated block copolymer represented by formula (1), more preferably a hydrogenated block copolymer represented by formula (1) where m is 3 or less, even more preferably a hydrogenated block copolymer represented by formula (1) where m is 2 or less, and particularly preferably a hydrogenated block copolymer represented by formula (1) where m is 1.

[0038] The number-average molecular weight of component (A) is not limited, but is preferably 100,000 or more, more preferably 150,000 or more, even more preferably 170,000 or more, and is preferably 600,000 or less, more preferably 550,000 or less, and even more preferably 500,000 or less, as measured by gel permeation chromatography (hereinafter sometimes abbreviated as GPC) in terms of polystyrene equivalent.

[0039] Examples of component (A) include styrene-butadiene-styrene block copolymer and its hydrogenated products, styrene-isoprene-butadiene-styrene block copolymer and its hydrogenated products, etc. Examples of hydrogenated styrene-butadiene-styrene block copolymers include styrene-ethylene-butylene-styrene copolymer (SEBS). Examples of hydrogenated styrene-isoprene-butadiene-styrene block copolymers include styrene-ethylene-ethylene-propylene-styrene copolymer (SEEPS). Among these, hydrogenated styrene-butadiene-styrene block copolymers are preferred because they tend to provide high fluidity and good fusion properties.

[0040] Examples of commercially available components (A) include "TAIPOL(registered trademark)-6151" and "TAIPOL(registered trademark)-6159" manufactured by Taiwan Synthetic Rubber Co., Ltd., "G1651" and "G1633" manufactured by Kraton Polymer Japan Co., Ltd., and "Septon(registered trademark) 4099" manufactured by Kuraray Co., Ltd.

[0041] The above component (A) may be used alone, or two or more components with different compositions and physical properties may be used in combination.

[0042] [Component (B)] The component (B) used in this invention is unmodified polypropylene.

[0043] In this invention, "polypropylene" means a material having a propylene unit content of 50% by mass or more, and includes both materials composed of a single resin component and materials composed of multiple resin components. The propylene unit content of unmodified polypropylene in component (B) is preferably 85 to 100% by mass, more preferably 90 to 100% by mass, and even more preferably 94 to 100% by mass. When the propylene unit content of component (A) is above the aforementioned lower limit, the heat resistance and rigidity tend to be good. The propylene unit content in component (A) can be determined by infrared spectroscopy.

[0044] Component (B) may be a homopolymer of propylene, or it may be a propylene copolymer containing, in addition to propylene units, ethylene units, α-olefin units other than propylene, monomer units other than ethylene and α-olefins, preferably in an amount of 15% by mass or less, more preferably 10% by mass or less, and even more preferably 6% by mass or less.

[0045] Examples of α-olefin units other than propylene include α-olefins having 4 to 20 carbon atoms. Examples of α-olefins having 4 to 20 carbon atoms include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-ethyl-1-hexene, 2,2,4-trimethyl-1-pentene, etc. Preferably, they are α-olefins having 4 to 10 carbon atoms, and more preferably, 1-butene, 1-hexene, and 1-octene. The propylene copolymer may contain only one of these α-olefin units and ethylene units, or it may contain two or more of them.

[0046] Specific examples of unmodified polypropylene of component (B) include propylene homopolymer, propylene-ethylene copolymer, propylene-1-butene copolymer, propylene-1-hexene copolymer, propylene-1-octene copolymer, propylene-ethylene-1-butene copolymer, propylene-ethylene-1-hexene copolymer, propylene-ethylene-1-octene copolymer, and propylene-based block copolymers obtained by polymerizing a propylene homopolymer in the first step and then polymerizing a propylene-ethylene copolymer in the second step. Preferably, it is a propylene-ethylene copolymer.

[0047] Among these, a propylene copolymer containing 6% by mass or less of one or more monomer units selected from ethylene units, butene units, hexene units, and octene units is preferred as component (B) from the viewpoint of compatibility with component (A).

[0048] The melt flow rate (MFR) of component (B) is not limited, but from the viewpoint of the fusion properties between the joining member and the members to be joined and the appearance of the molded article, it is usually 1 g / 10 min or more, preferably 10 g / 10 min or more, more preferably 20 g / 10 min or more, and even more preferably 25 g / 10 min or more. Furthermore, the melt flow rate of component (B) is usually 100 g / 10 min or less, preferably 80 g / 10 min or less, and more preferably 60 g / 10 min or less, from the viewpoint of tensile strength. The melt flow rate of component (B) is measured in accordance with JIS K7210 (1999) under conditions of a measurement temperature of 230°C and a measurement load of 21.2N.

[0049] If component (B) consists of a blend of unmodified polypropylenes having different MFRs, the MFR of component (B) can be calculated by the following formula (I). log(MFR blend) = w1log(MFR1) + w2log(MFR2) + ... + wilog(MFRi) + ... + wnlog(MFRn) ... (I) In equation (I), wi is the weight fraction of component i, MFRi is the MFR of component i, and n is the total number of components in the blend. w1 + w2 + ... + wi + ... + wn = 1.

[0050] Preferably, the melting peak temperature of component (B) is observed at a temperature of at least 100°C or higher and less than 157°C. The melting peak of component (B) being within the above numerical range is preferable from the viewpoint of heat resistance and compatibility with component (A). The melting peak temperature of component (B) can be measured according to JIS K7121 by the following method. Specifically, the melting behavior of polypropylene is measured by sequentially performing the following steps (1) to (3) using a differential scanning calorimeter (DSC6220 manufactured by SSI Nanotechnology). In each process, time is plotted on the horizontal axis and the amount of heat of fusion on the vertical axis to obtain a melting curve, and the peak top of the peak observed in process (3) is defined as the melting peak temperature. Step (1): Heat 5 mg of the sample from room temperature at a rate of 100°C / min from 40°C to 200°C, and hold the temperature for 3 minutes after the heating is complete. Step (2): Cool the temperature from 200°C to 40°C at a rate of 10°C / min, and hold for 3 minutes after the cooling is complete. Step (3): Increase the temperature from 40°C to 200°C at a rate of 10°C / min.

[0051] As a method for producing unmodified polypropylene of component (B), known polymerization methods using known olefin polymerization catalysts can be used. For example, a multi-stage polymerization method using a Ziegler-Natta catalyst can be used. This multi-stage polymerization method can include slurry polymerization, solution polymerization, bulk polymerization, gas-phase polymerization, etc., and two or more of these may be combined.

[0052] Ingredient (B) can also be a commercially available product. Ingredient (B) can be procured from the manufacturers listed below and can be selected as appropriate. Examples of commercially available products include Prime Polypro® from Prime Polymer, Sumitomo Noblen® from Sumitomo Chemical, Polypropylene Block Copolymer from Sun Allomer, Novatec® PP from Nippon Polypropylene, Moplen® from LyondellBasell, Vistamaxx® and ExxonMobil PP from ExxonMobil, Formolene® from Formosa Plastics, Borealis PP from Borealis, Seetec PP from LG Chemical, ASI Polypropylene from A. Schulman, INEOS PP from INEOS Olefins & Polymers, Braskem PP from Braskem, Samsung Total from Samsung Total Petrochemicals, Sabic® PP from Sabic, Total Petrochemicals Polypropylene from Total Petrochemicals, and YUPLENE® from SK.

[0053] The above component (B) may be used alone, or two or more components with different compositions and physical properties may be used in combination.

[0054] [Component (C)] The modified polypropylene (hereinafter sometimes referred to as "(meth)acrylic acid-modified polypropylene"), which is component (C) used in the present invention, functions as an improver in the crosslinked thermoplastic elastomer resin composition of the present invention to improve the fusion durability with the joined members during heat fusion.

[0055] As the polypropylene used as the raw material for component (C), unmodified polypropylene of component (B) can be used. Among these, propylene homopolymer and propylene-ethylene random copolymer are preferred because they are relatively inexpensive and readily available, and propylene homopolymer is more preferred from the viewpoint of obtaining high adhesion due to the effect of molecular entanglement at the bonding surface with the members to be joined during heat fusion.

[0056] The density of polypropylene used as a raw material for component (C) (according to ISO 1183 Method A (water displacement method)) is not particularly limited, but is 0.85 g / cm³. 3 The above is preferable, and more preferably 0.87 g / cm³. 3 That is all, on the other hand, 0.96 g / cm³ 3 The following is preferred, and more preferably, 0.95 g / cm³. 3 The following applies:

[0057] Furthermore, the melt flow rate (MFR, compliant with JIS K7210:1999, 230°C, load 21.2N) of the polypropylene used as a raw material for component (C) is not particularly limited, but from the viewpoint of moldability, it is preferably 0.01 to 200 g / 10 min, and more preferably 0.1 to 80 g / 10 min.

[0058] Many propylene-based copolymers, such as propylene homopolymers and propylene-α-olefin copolymers, that satisfy the above physical properties are commercially available in various grades from domestic and international manufacturers, and commercially available products of various grades can be used as the polypropylene raw material for component (C).

[0059] Component (C), (meth)acrylic acid-modified polypropylene, is obtained by modifying the above-mentioned polypropylene with (meth)acrylic acid and / or its derivatives. Examples of (meth)acrylic acid derivatives include (meth)acrylic acid esters, amides, imides, and metal salts. Specifically, examples include, but are not limited to, methyl (meth)acrylate, ethyl (meth)acrylate, glycidyl (meth)acrylate, (meth)acrylamide, sodium (meth)acrylate, and potassium (meth)acrylate.

[0060] (Meth)acrylic acid and / or its derivatives may be used individually, or two or more may be used in any combination in any ratio as appropriate. Among these, (meth)acrylic acid and (meth)acrylic acid esters are preferred, and more preferably (meth)acrylic acid and glycidyl (meth)acrylic acid.

[0061] The amount of (meth)acrylic acid and / or its derivatives used to modify polypropylene is usually 0.01 parts by mass or more, preferably 0.1 parts by mass or more, per 100 parts by mass of polypropylene used as a raw material for component (C), while usually 20 parts by mass or less, preferably 10 parts by mass or less. If the amount of (meth)acrylic acid and / or its derivatives used is above the lower limit, the resulting crosslinked thermoplastic elastomer composition tends to have good adhesion. On the other hand, if it is below the upper limit, the generation of unreacted materials and by-products is suppressed, which tends to prevent deterioration of the product appearance due to fish eyes, blemishes, etc., in molded articles using the resulting crosslinked thermoplastic elastomer composition, and also tends to suppress a decrease in adhesion.

[0062] The modification using (meth)acrylic acid and / or its derivatives described above is preferably performed by graft modification, and graft modification can be carried out by various conventionally known methods. Examples of modification methods include, but are not limited to, a melt modification method in which (meth)acrylic acid and / or its derivatives are added to molten polypropylene and graft copolymerization is carried out; a solution modification method in which (meth)acrylic acid and / or its derivatives are added to polypropylene dissolved in a solvent and graft copolymerization is carried out; and a solid-phase polymerization method in which (meth)acrylic acid and / or its derivatives are added to solid polypropylene and graft copolymerization is carried out.

[0063] As a melt modification method, polypropylene and (meth)acrylic acid and / or its derivatives are melted using an extruder or the like at a temperature above the melting point of the polypropylene (e.g., 170-290°C) and reacted for typically 0.5-10 minutes. As a solution modification method, polypropylene, (meth)acrylic acid and / or its derivatives, and optionally a radical initiator are added to an organic solvent and reacted at a temperature above the melting point of the polypropylene (e.g., 170-290°C) for typically 0.5-15 hours, preferably 1-10 hours. As a solid-phase polymerization method, solid polypropylene, (meth)acrylic acid and / or its derivatives, and optionally a radical initiator are added and reacted at a temperature below the melting point of the polypropylene (e.g., 20-150°C) for typically 1-24 hours, preferably 1-10 hours. Among these, from a hygienic viewpoint, the melt modification method and solid-phase polymerization method, which do not require the use of solvents, are preferred. Furthermore, in order to efficiently perform graft modification, it is preferable to perform the modification in the presence of a radical initiator.

[0064] The radical initiator is not particularly limited, but organic peroxides or azo compounds are preferred, and organic peroxides are particularly preferred. Specifically, dialkyl peroxides such as di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexine-3, 1,4-bis(t-butylperoxyisopropyl)benzene, 1,1-bis(t-butylperoxy)cyclohexane, n-butyl-4,4-bis(t-butylperoxy)balate, 2,2-bis(4,4-t-butylperoxycyclohexyl)propane, 2,2-bis(t-butylperoxy)butane, 1,1-bis(t-butylperoxy)cyclododecane; t-butyl peroxyacetate, t-butylperoxy-2-ethylhexanoate, t-butylperoxypivalate, t-butylperoxylaurate, t-butylperoxybenzoate, t-butylperoxyisopropyl Examples of peroxy esters include peroxy carbonates, t-butyl peroxymalic acid, di-t-butyl peroxyisophthalate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexine-3, and 2,5-dimethyl-2,5-di(toluylperoxy)hexane; diacyl peroxides such as di-3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, and dibenzoyl peroxide; hydroperoxides such as t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, and 2,5-dimethyl-2,5-di(hydroperoxy)hexane; and ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide. Radical initiators can be used individually or in combination of two or more in any ratio as appropriate.

[0065] Among these, radical initiators with a decomposition temperature of 100°C or higher at which a half-life of 1 minute is obtained are preferred from the viewpoint of graft modification efficiency. Specifically, diaryls such as di-t-butyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, and 2,5-dimethyl-2,5-di(t-butylperoxy)hexyn-3 are preferred. Peroxides or peroxyesters such as t-butyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, and 2,5-dimethyl-2,5-di(benzoylperoxy)hexyn-3 are preferred.

[0066] The amount of radical initiator used is not particularly limited, but it is preferable to use an amount of 0.001 parts by mass or more and 1 part by mass or less per 100 parts by mass of the raw material polypropylene.

[0067] The modification rate of (meth)acrylic acid and / or its derivatives in (meth)acrylic acid-modified propylene is not particularly limited, but is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 0.7% by mass or more, relative to the total amount of (meth)acrylic acid-modified polypropylene, while preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 5% by mass or less. Although it varies depending on the polypropylene used as a raw material, if the (meth)acrylic acid modification rate falls outside the above preferred range, the melt viscosity tends to increase or decrease, making it easier for defects in appearance to occur when molded.

[0068] Here, the modification rate (graft rate) can be measured by, for example, the following method: dissolve (meth)acrylic acid-modified polypropylene in a solvent such as orthodichlorobenzene or paradichlorobenzene, 13By measuring 13C-nuclear magnetic resonance (NMR), the carbon atoms contained in the polypropylene backbone and the carbon atoms contained in the (meth)acrylic acid and / or its derivative backbone can be distinguished and quantified, and the grafting rate can be measured from their area ratio. In the graft modification of (meth)acrylic acid-modified polypropylene, unreacted (meth)acrylic acid and / or its derivative may remain, but the grafting rate in this specification means the value measured by 13C-NMR for (meth)acrylic acid-modified polypropylene as described above. 13 It shall mean the value measured by 13C-NMR.

[0069] The density of the (meth)acrylic acid-modified polypropylene is not particularly limited, but it is the density measured in accordance with Method A (water substitution method) of ISO 1183, and preferably 0.85 g / cm 3 or more, more preferably 0.87 g / cm 3 or more. On the other hand, it is preferably 0.96 g / cm 3 or less, more preferably 0.95 g / cm 3 or less. [[ID=十六]]Also, the melt flow rate (MFR) of the (meth)acrylic acid-modified polypropylene is not particularly limited, but is preferably 0.01 to 3000 g / 10 min, more preferably 0.1 to 2500 g / 10 min. Here, the MFR of the (meth)acrylic acid-modified polypropylene means the value measured under the conditions of 230 °C and a load of 2.16 kg in accordance with JIS K7210:1999.

[0070] In the crosslinked thermoplastic elastomer composition of the present invention, only one kind or two or more kinds of the (meth)acrylic acid-modified polypropylene of component (C) may be used.

[0071] Examples of commercially available products of component (C) include "SCONA T Polypropylene 2110 FA" manufactured by BYK Chemie.

[0072] [Component (D)] As the lubricant for component (D), a silicone-based lubricant can be suitably used, such as silicone oil, silicone masterbatch, or liquid siloxane wax. More preferably, a silicone oil is used.

[0073] [Component (E)] The thermoplastic elastomer composition of the present invention may contain a softening agent as component (E).

[0074] The softener for component (E) is not particularly limited and any known softener can be used, but hydrocarbon-based rubber softeners are particularly preferred. Examples of hydrocarbon-based rubber softeners include mineral oil-based softeners and synthetic resin-based softeners, but mineral oil-based softeners are preferred from the viewpoint of affinity with other components. Mineral oil-based softeners are generally mixtures of aromatic hydrocarbons, naphthenic hydrocarbons and paraffinic hydrocarbons, with paraffinic oils being those in which 50% or more of the total carbon atoms are paraffinic hydrocarbons, naphthenic oils being those in which 30-45% of the total carbon atoms are naphthenic hydrocarbons, and aromatic oils being those in which 35% or more of the total carbon atoms are aromatic hydrocarbons. Among these, paraffinic oil is preferred in the present invention.

[0075] The kinematic viscosity of component (E) of the softener at 40°C is not particularly limited, but is preferably 20 cSt or more, more preferably 50 cSt or more, and also preferably 800 cSt or less, more preferably 600 cSt or less. The flash point (COC method) of the softener is preferably 200°C or more, more preferably 250°C or more.

[0076] The softening agent in component (E) is available commercially. Examples of such commercially available products include the "Nisseki Polybutene (registered trademark) HV" series from JX Nippon Oil & Energy Corporation and the "Diana (registered trademark) Process Oil PW" series from Idemitsu Kosan Co., Ltd., and the appropriate product can be selected and used from among these as needed.

[0077] The softening agent of component (E) may be used alone, or two or more may be used in any combination and ratio.

[0078] [Component(f)] The crosslinked thermoplastic elastomer composition of the present invention is obtained by dynamic heat treatment in the presence of a crosslinking agent of component (f). By performing dynamic heat treatment in the presence of a crosslinking agent of component (f) and crosslinking at least a portion of component (A), good rubber elasticity can be achieved. The crosslinked thermoplastic elastomer composition may contain crosslinking agent reaction products.

[0079] Organic peroxides, phenolic resins, and other crosslinking aids can be used as crosslinking agents. These crosslinking agents may be used individually or in combination of two or more.

[0080] Both aromatic and aliphatic organic peroxides can be used as crosslinking agents. Specifically, examples include dialkyl peroxides such as di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexine, 1,3-bis(t-butylperoxyisopropyl)benzene, and 1,1-di(t-butylperoxy)-3,3,5-trimethylcyclohexane; peroxyesters such as t-butyl peroxybenzoate, t-butylperoxyisopropyl carbonate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, and 2,5-dimethyl-2,5-di(benzoylperoxy)-3-hexine; and hydroperoxides such as acetyl peroxide, lauroyl peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide, and 2,4-dichlorobenzoyl peroxide. Among these, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane is preferred. These organic peroxides may be used individually or in combination of two or more.

[0081] Examples of phenolic resins that can be used as crosslinking agents include alkylphenol formaldehyde and alkylphenol bromide formaldehyde. These phenolic resins may be used individually or in combination of two or more.

[0082] Examples of crosslinking aids other than phenolic resins include peroxide aids such as sulfur, p-quinone dioxime, p-dinitrosobenzene, and 1,3-diphenylguanidine; crosslinking aids for phenolic resins such as stannous chloride anhydrous, stannous chloride dihydrate, and ferric chloride; polyfunctional vinyl compounds such as divinylbenzene, triallyl cyanurate, triallyl isocyanurate, and diallyl phthalate; and polyfunctional (meth)acrylate compounds such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and allyl(meth)acrylate. These may be used individually or in combination of two or more.

[0083] [Other ingredients] In the production of the crosslinked thermoplastic elastomer composition of the present invention, other components may be used as raw materials as necessary, in addition to components (A) to (E) and (f), as long as they do not impair the effects of the present invention.

[0084] Other components include, for example, resins such as thermoplastic resins and elastomers other than components (A), (B), and (C), antioxidants, fillers, heat stabilizers, light stabilizers, UV absorbers, neutralizing agents, antifogging agents, antiblocking agents, slip agents, dispersants, colorants, flame retardants, antistatic agents, conductivity imparters, metal deactivators, molecular weight modifiers, antibacterial agents, antifungal agents, fluorescent whitening agents, and various other additives. Any of these can be used individually or in combination.

[0085] Examples of thermoplastic resins other than components (A), (B), and (C) include polyphenylene ether resins; polyamide resins such as nylon 6 and nylon 66; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polyoxymethylene resins such as polyoxymethylene homopolymer and polyoxymethylene copolymer; polymethyl methacrylate resins and polyolefin resins (excluding those corresponding to components (B) and (C)). Examples of elastomers other than components (A), (B), and (C) include polyester elastomers and polybutadiene.

[0086] Examples of antioxidants (hereinafter sometimes referred to as "component (G)") include phenolic antioxidants, phosphite antioxidants, and thioether antioxidants. When using an antioxidant, it is usually used in an amount of 0.01 to 3.0 parts by mass, preferably 0.15 to 0.6 parts by mass, per 100 parts by mass of the total component (A). Good thermal stability can be obtained within this range.

[0087] [Content ratio] The crosslinked thermoplastic elastomer composition of the present invention preferably contains 40 to 120 parts by mass of component (B) per 100 parts by mass of component (A) from the viewpoint of achieving both moldability and flexibility. From the viewpoint of moldability, the lower limit of the content of component (B) is more preferably 50 parts by mass or more, and even more preferably 60 parts by mass or more. On the other hand, from the viewpoint of obtaining sufficient flexibility and hardness, the upper limit of the content of component (B) is more preferably 110 parts by mass or less, and even more preferably 100 parts by mass or less.

[0088] The crosslinked thermoplastic elastomer composition of the present invention preferably contains 1 to 50 parts by mass of component (C) per 100 parts by mass of component (A) to sufficiently improve the fusion properties to thermoplastic elastomer compositions containing propylene resin as the base phase. The lower limit of the content of component (C) is more preferably 6 parts by mass or more, and even more preferably 16 parts by mass or more, from the viewpoint of improving compression set. On the other hand, the upper limit of the content of component (C) is more preferably 42 parts by mass or less, and even more preferably 33 parts by mass or less, from the viewpoint of ensuring fluidity.

[0089] The crosslinked thermoplastic elastomer composition of the present invention uses component (D) in an amount of typically 0.5 to 50 parts by mass, preferably 1 to 25 parts by mass, per 100 parts by mass of component (A). The crosslinked thermoplastic elastomer composition of the present invention can obtain sufficient sliding properties while suppressing a decrease in fusion properties by adding a small amount of component (D), more preferably 20 parts by mass or less, per 100 parts by mass of component (A).

[0090] In the crosslinked thermoplastic elastomer composition of the present invention, the lower limit of the amount of crosslinking agent in component (f) is preferably 0.05 parts by mass or more, more preferably 0.10 parts by mass or more, and even more preferably 0.20 parts by mass or more, per 100 parts by mass of component (A), from the viewpoint of ensuring sufficient crosslinking. On the other hand, the upper limit of the amount of crosslinking agent in component (f) is preferably 5.0 parts by mass or less, more preferably 4.5 parts by mass or less, and even more preferably 4.0 parts by mass or less, per 100 parts by mass of component (A), from the viewpoint of controlling attack on the propylene chain.

[0091] When the crosslinked thermoplastic elastomer composition of the present invention contains component (E), the lower limit of the content of component (E) per 100 parts by mass of component (A) is usually 100 parts by mass or more, preferably 102 parts by mass or more, and more preferably 104 parts by mass or more, from the viewpoint of moldability. On the other hand, the upper limit of the content of component (E) is usually 140 parts by mass or less, preferably 138 parts by mass or less, and more preferably 136 parts by mass or less, from the viewpoint of flexibility.

[0092] When a crosslinked thermoplastic elastomer composition of a preferred embodiment of the present invention contains components other than components (A) to (D) and component (E), in order to fully obtain the effects of containing components (A) to (D) and component (E), the content of the other components is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, relative to 100 parts by mass of the total of components (A) and component (B) (however, if component (E) is included, the total of components (A), (B), and (E) is 100 parts by mass or more). Furthermore, the content of the other components is preferably 30 parts by mass or less, more preferably 29 parts by mass or less, and even more preferably 28 parts by mass or less, relative to 100 parts by mass of the total of components (A) and component (B) (however, if component (E) is included, the total of components (A), (B), and (E) is 100 parts by mass or more).

[0093] [Method for producing crosslinked thermoplastic elastomer compositions] The crosslinked thermoplastic elastomer resin composition of the present invention is obtained by dynamic heat treatment by melt-kneading a material composition of a crosslinked thermoplastic elastomer composition containing components (A), (B), (C), and (D) in the presence of component (f). More preferably, it is obtained by dynamic heat treatment by melt-kneading a material composition containing components (A), (B), (C), (D), and (E) in the presence of component (f). By performing this dynamic heat treatment in the presence of component (f) and crosslinking at least a portion of component (A), the sliding properties can be improved.

[0094] In the present invention, "dynamic heat treatment" means kneading in a molten or semi-molten state in the presence of an organic peroxide. This dynamic heat treatment is preferably carried out by melt kneading, and suitable melt kneading equipment for this purpose includes, for example, a closed-type Banbury mixer, mixing rolls, a kneader, and a twin-screw extruder. Among these, the use of a twin-screw extruder is preferred. A preferred embodiment of the manufacturing method using this twin-screw extruder is to supply each component to the raw material supply port (hopper) of a twin-screw extruder having multiple raw material supply ports and perform the dynamic heat treatment.

[0095] The temperature during dynamic heat treatment is typically 80 to 300°C, preferably 100 to 250°C. The duration of the dynamic heat treatment is typically 0.1 to 30 minutes.

[0096] When the crosslinked thermoplastic elastomer composition of the present invention is manufactured by dynamic heat treatment using a twin-screw extruder, it is preferable to extrude while maintaining the relationship shown in formula (i) below between the barrel radius (R (mm)), screw rotation speed (N (rpm)), and discharge rate (W (kg / hour)) of the twin-screw extruder, and more preferably while maintaining the relationship shown in formula (ii) below. 2.6 <NW / R 3 <22.6 (i) 3.0 <NW / R 3 <20.0 (ii)

[0097] For efficient production of thermoplastic elastomer compositions, it is preferable that the relationship between the barrel radius (R (mm)), screw rotation speed (N (rpm)), and discharge rate (W (kg / hour)) of a twin-screw extruder is greater than the lower limit. On the other hand, it is preferable that the relationship is smaller than the upper limit because it suppresses heat generation due to shear and reduces the generation of foreign matter that causes defects in appearance.

[0098] [Physical properties of crosslinked thermoplastic elastomer compositions] From the viewpoint of moldability, the crosslinked thermoplastic elastomer composition of the present invention preferably has a melt flow rate (MFR) of 5 g / 10 min or more, more preferably 10 g / 10 min or more, and even more preferably 15 g / 10 min or more, measured in accordance with the JIS K7210 standard at a measurement temperature of 230 °C and a measurement load of 21.2 N. Furthermore, from the viewpoint of moldability, the melt flow rate (MFR) is preferably 150 g / 10 min or less, more preferably 145 g / 10 min or less, and even more preferably 140 g / 10 min or less.

[0099] From the viewpoint of weight reduction, the crosslinked thermoplastic elastomer composition of the present invention has a density of 1.11 g / cm³ as measured in accordance with ISO 1183 Method A (water displacement method). 3 Preferably, the following, and more preferably, 1.00 g / cm³ 3 The following, and more preferably, 0.97 g / cm³ 3 The following applies: The lower limit of density is generally 0.90 g / cm³, derived from the density of polypropylene. 3 That's all.

[0100] From the viewpoint of its use as a bonding member, the crosslinked thermoplastic elastomer composition of the present invention preferably has a hardness duro A measured 15 seconds after pressing a needle against a test piece, in accordance with ISO 7619, which is in the range of 35 to 98, and more preferably in the range of 40 to 95.

[0101] From the viewpoint of its use as a bonding member, the crosslinked thermoplastic elastomer composition of the present invention preferably has a lower limit of tensile stress at break measured at 23°C in accordance with the ISO 37 Type 1A (test speed 500 mm / min) method for measuring tensile stress at break, which is 7 MPa or higher, more preferably 8 Pa or higher, and even more preferably 9 MPa or higher. The upper limit of the tensile stress at break is usually less than 15 MPa, more preferably 14 MPa or lower, and even more preferably 13 MPa or lower.

[0102] From the viewpoint of its use as a bonding member, the crosslinked thermoplastic elastomer composition of the present invention preferably has a lower limit of elongation at break of 400% or more, more preferably 500% or more, and even more preferably 600% or more, measured using a procedure compliant with the ISO 37 Type 1A (test speed 500 mm / min) method for measuring elongation at break. The upper limit of elongation at break is preferably 1300% or less, more preferably 1200% or less, and even more preferably 1100% or less.

[0103] [Molded object / Application] The crosslinked thermoplastic elastomer composition of the present invention can be molded into a molded article by various molding methods commonly used for crosslinked thermoplastic elastomer compositions, such as injection molding, extrusion molding, hollow molding, and compression molding, with injection molding being preferred among these. Furthermore, the molded article can also be subjected to secondary processing such as lamination molding or thermoforming after these molding processes.

[0104] Molded articles made from the crosslinked thermoplastic elastomer composition of the present invention can be applied to a wide range of fields, including: automotive parts such as skins, weatherstrips, ceiling materials, interior sheets, bumper moldings, side moldings, air spoilers, air duct hoses, and sealing materials; civil engineering and construction materials such as water-stopping materials, joint materials, window frames, and sealing materials; sports equipment such as golf club grips and tennis racket grips; industrial parts such as hose tubes and gaskets; home appliance parts such as hoses and packings; medical parts such as medical containers, gaskets, and packings; food products such as containers and packings; medical equipment parts; electric wires; and general merchandise. Molded articles made from the crosslinked thermoplastic elastomer composition of the present invention are particularly suitable as automotive sealants and building material sealants among those listed above, and are especially suitable as automotive glass run channels.

[0105] [Joining members] The joining member of the present invention consists of the crosslinked thermoplastic elastomer composition of the present invention described above, and is manufactured by injection molding a molten mixture obtained by melt-kneading the crosslinked thermoplastic elastomer composition of the present invention.

[0106] In particular, the joining member of the present invention is suitable as a joining member used in automotive composite molded articles such as automotive glass run channels. Figure 1 is a perspective view showing an example of a glass run channel for automobiles as a composite molded body 3. This composite molded body 3 is formed by fusion bonding and integrating joined members 1A and 1B, which constitute linear portions manufactured separately by extrusion molding of a thermoplastic elastomer composition, at a corner portion which is a joining member 2 made of the crosslinked thermoplastic elastomer composition of the present invention.

[0107] Such a composite molded body 3 can be manufactured, for example, by inserting the joining ends of pre-fabricated members to be joined 1A and 1B into an injection molding die, and injecting the crosslinked thermoplastic elastomer composition of the present invention into the die to form the joining member 2 at the corner portion, while simultaneously fusing and integrating it with the end faces of the members to be joined 1A and 1B. [Examples]

[0108] The present invention will be described in more detail below using examples, but the present invention is not limited to the following examples unless it exceeds its gist. The various manufacturing conditions and evaluation result values ​​in the following examples have meaning as preferred upper or lower limits in embodiments of the present invention, and the preferred range may be defined by a combination of the aforementioned upper or lower limits and the values ​​of the following examples or the values ​​of the examples themselves.

[0109] 〔raw materials〕 The raw materials used in the following examples and comparative examples are as follows:

[0110] [Component (A): Styrene elastomer] <a-1> Hydrogenated styrene-butadiene-styrene block copolymer (having the structure of formula (1) above; styrene (block P) content: 32% by mass, number average molecular weight: 200,000) / "TAIPOL-6151" manufactured by Taiwan Synthetic Rubber Co., Ltd. (TSRC)

[0111] [Component (B): Unmodified polypropylene] <b-1> Propylene-ethylene copolymer (MFR (JIS K7210): 30g / 10 min (230℃, 21.2N), melting peak temperature: 155℃, propylene unit content: 98% by mass, ethylene unit content: 2% by mass) / Manufactured by Nippon Polypropylene Co., Ltd. "Novatec (registered trademark) PP MG03BD"

[0112] [Component (C): (meth)acrylic acid modified polypropylene] <c-1> Acrylic acid-modified homopolypropylene (MFR (JIS K7210): 3.6g / 10 min (230℃, load 21.2N), modification rate: 2.0% by mass) / BYK "SCONA T Polypropylene 2110 FA"

[0113] [Ingredient (D): Lubricant] <d-1> Silicone oil / Shin-Etsu Chemical Co., Ltd. "KF96-100CS"

[0114] [Ingredient (E): Hydrocarbon rubber softener] <e-1> Paraffin-based rubber softener (kinematic viscosity at 40°C: 95.5 cSt, flash point: 272°C) / "Diana® Process Oil PW90" manufactured by Idemitsu Kosan Co., Ltd.

[0115] [Component (f): Crosslinking agent] <f-1> A mixture of 40 parts by mass of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane and 60 parts by mass of calcium carbonate / "Kayahexa AD40C" manufactured by Kayaku Akzo Co., Ltd. <f-2> A mixture of 55 parts by mass of divinylbenzene and 45 parts by mass of ethylvinylbenzene / Crosslinking aid for "Divinylbenzene" manufactured by Wako Pure Chemical Industries, Ltd.

[0116] [Ingredient (G): Antioxidant] <g-1> Phenolic antioxidant / BASF Japan's "Irganox (registered trademark) 1010"

[0117] [Evaluation Method] The evaluation methods for the crosslinked thermoplastic elastomer compositions in the following examples and comparative examples are as follows.

[0118] For the measurements in (1) to (5) and (7) below, each crosslinked thermoplastic elastomer composition was used, and sheets (120 mm wide, 80 mm long, 2 mm thick) obtained by injection molding using an in-line screw-type injection molding machine (Toshiba Machine Co., Ltd. "IS130") under the conditions of injection pressure of 50 MPa, cylinder temperature of 220°C, and mold temperature of 40°C were used.

[0119] (1) Hardness Duro A: The value was measured 15 seconds after pressing the needle against the test specimen, in accordance with ISO 7619.

[0120] (2) Density: Measured according to ISO 1183 Method A (water displacement method).

[0121] (3) Tensile stress at break: The procedure was carried out at 23°C in accordance with the method for measuring tensile stress at break of ISO 37 Type 1A (test speed 500 mm / min).

[0122] (4) Elongation at break: The procedure was carried out in accordance with the method for measuring elongation at break of ISO 37 Type 1A (test speed 500 mm / min).

[0123] (5) Static friction coefficient and kinetic friction coefficient A sheet obtained by injection molding (120mm wide, 80mm long, 2mm thick) was cut to a size of 63mm x 63mm. This test piece was placed on a glass plate (110mm long x 110mm wide x 3mm thick), and a load of 500g was placed on top of it. The plate was then moved 30mm at a speed of 100mm / min to measure the static and dynamic friction coefficients. The measurement conditions were as follows: (Measurement conditions) Equipment: Shinto Kagaku Co., Ltd. "Tribogear Type: HEIDON-38" Measurement mode: Constant load measurement Temperature during measurement: 23℃ Measuring indenter: ASTM flat indenter Furthermore, the coefficient of kinetic friction was evaluated according to the following criteria. ○: Coefficient of dynamic friction less than 1.00 △: Coefficient of dynamic friction between 1.00 and less than 1.10 ×: Coefficient of dynamic friction 1.10 or higher

[0124] (6) Method of fusion with thermoplastic elastomer composition containing propylene resin as the base phase and evaluation of fusion durability (bending test) A 1mm thick injection-molded sheet of a thermoplastic elastomer composition containing propylene resin as the base phase (TREXPRENE® 3855N, a dynamically crosslinked thermoplastic elastomer manufactured by Mitsubishi Chemical Corporation) was cut to a size of 10cm x 5cm and loaded into the mold of a 110-ton injection molding machine. Each crosslinked thermoplastic elastomer composition was injected into the mold at a cylinder temperature of 230°C and a mold temperature of 50°C to obtain a composite molded body by insert molding. The composite molded body was punched out using a JIS K7195 heat sag dumbbell (width 25mm x length 150mm), and a bending test was performed at a rate of once per second, with each set consisting of a 180-degree bend to the left and right around the fusion interface. For a total of three test pieces, the number of bend sets at which cracks appeared at the fusion interface was recorded, and the average value was calculated. A higher average value indicates superior fusion durability. In this evaluation, the maximum number of folds was set at 100. In the table, "100" indicates that no cracks appeared even after 100 folds. This evaluation assesses the fusion durability using injection-molded sheets, and the results of this evaluation allow for a reproducible assessment of the quality of fusion durability when a composite molded body is formed, as shown in Figure 1.

[0125] (7) Compression set: Measured in accordance with ISO 815 under conditions of 70°C, 22 hours, and 25% compression.

[0126] [Examples / Comparative Examples] <Example 1> (A-1) 100 parts by mass, (B-1) 100 parts by mass, (C-1) 16.7 parts by mass, (D-1) 10 parts by mass, (E-1) 133 parts by mass, (f-1) 2.0 parts by mass (a mixture of 40 parts by mass of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane and 60 parts by mass of calcium carbonate), (f-2) 2.0 parts by mass (a mixture of 55 parts by mass of divinylbenzene and 45 parts by mass of ethylvinylbenzene), and (G-1) 0.33 parts by mass were blended in a Henschel mixer for 1 minute to obtain a material composition. This material composition was fed into the feed section of a co-screw extruder (TEX30α manufactured by Japan Steel Works, L / D=46, number of cylinder blocks: 13) at a total speed of 15 kg / h, heated to a temperature range of 110~220°C, and melt-kneaded to obtain pellets, which are a crosslinked thermoplastic elastomer composition. The obtained crosslinked thermoplastic elastomer composition was subjected to the mel flow rate (MFR) measurement at a measurement temperature of 230°C and a measurement load of 21.2 N, in accordance with the JIS K7210 standard, and the evaluations described in (1) to (7) above were performed. The evaluation results are shown in Table 1.

[0127] <Example 2, Comparative Example 1> The procedure was carried out in the same manner as in Example 1, except for the blending ratios shown in Table 1, to obtain pellets that are a crosslinked thermoplastic elastomer composition. The obtained crosslinked thermoplastic elastomer composition was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0128] In Table 1, component (f-1) is shown not as the actual amount blended, but as the amount of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane only (40% by mass of the actual blended amount), and component (f-2) is also shown not as the actual amount blended, but as the amount of divinylbenzene only (55% by mass of the actual blended amount). Furthermore, the information regarding component (G-1) in Table 1 has been omitted.

[0129] [Table 1]

[0130] <Evaluation Results> As shown in Table 1, the crosslinked thermoplastic elastomer compositions of Examples 1 and 2 exhibit excellent fusion durability and sliding properties. Comparative Example 1 is an example that does not use component (C), but its fusion durability is inferior. [Industrial applicability]

[0131] The crosslinked thermoplastic elastomer composition of the present invention can be used in a wide range of fields, including automotive parts such as skins, weatherstrips, ceiling materials, interior sheets, bumper moldings, side moldings, air spoilers, air duct hoses, and sealants; civil engineering and construction materials such as water-stopping materials, joint materials, window frames, and sealants; sports equipment such as golf club grips and tennis racket grips; industrial parts such as hose tubes and gaskets; home appliance parts such as hoses and packings; medical parts such as medical containers, gaskets, and packings; food products such as containers and packings; medical equipment parts; electric wires; and general merchandise. Among the above, the crosslinked thermoplastic elastomer composition of the present invention is particularly suitable as an automotive sealant and a building material sealant, and is especially suitable as an automotive corner sealant, particularly as an automotive glass run channel. [Explanation of symbols]

[0132] 1A,1B Parts to be joined 2 Joining members 3 Composite molded body

Claims

1. A crosslinked thermoplastic elastomer composition obtained by melt-kneading a material composition containing the following components (A), (B), (C), and (D) in the presence of the following component (f), wherein the crosslinked thermoplastic elastomer composition contains 40 to 120 parts by mass of component (B), 1 to 50 parts by mass of component (C), and 0.5 to 50 parts by mass of component (D) per 100 parts by mass of component (A). Ingredient (A): Styrene elastomer Component (B): Unmodified polypropylene Component (C): Modified polypropylene modified with (meth)acrylic acid and / or its derivatives, wherein the (meth)acrylic acid derivative is selected from among esters, amides, imides, and metal salts of (meth)acrylic acid. Ingredient (D): Lubricant Ingredient (f): Crosslinking agent

2. A crosslinked thermoplastic elastomer composition comprising the following components (A), (B), (C), and (D) in an amount of 40 to 120 parts by mass of component (B), 1 to 50 parts by mass of component (C), and 0.5 to 50 parts by mass of component (D) per 100 parts by mass of component (A), wherein the value of the tensile stress at break measured at 23°C in accordance with the method for measuring tensile stress at break of ISO 37 Type 1A (test speed 500 mm / min) is 7 MPa or more and less than 15 MPa. Ingredient (A): Styrene elastomer Component (B): Unmodified polypropylene Component (C): Modified polypropylene modified with (meth)acrylic acid and / or its derivatives, wherein the (meth)acrylic acid derivative is selected from among esters, amides, imides, and metal salts of (meth)acrylic acid. Ingredient (D): Lubricant

3. The crosslinked thermoplastic elastomer composition according to claim 1 or 2, wherein the melt flow rate (MFR) of the unmodified polypropylene of component (B) is 1 g / 10 min or more and 60 g / 10 min or less, as measured in accordance with JIS K7210 (1999) at a measurement temperature of 230°C and a measurement load of 21.2 N.

4. A bonding member comprising a crosslinked thermoplastic elastomer composition according to any one of claims 1 to 3.

5. A composite molded body for automobiles comprising the joining member described in claim 4.

6. Automotive corner material using the composite molded body described in claim 5.

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