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 having a modification rate with maleic acid and / or a derivative thereof of 1.0 mass% or more, 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 this crosslinked thermoplastic elastomer composition, and a composite molded article for automobiles and an automobile corner material using this joining member. [Background technology]

[0002] Thermoplastic elastomer compositions obtained by melt-kneading polypropylene resins and styrene-butadiene block copolymers and subjecting them to dynamic heat treatment exhibit the properties of rubber-like soft materials, but do not require a vulcanization process and have moldability similar to that of thermoplastic resins. For this reason, such thermoplastic elastomer compositions have attracted attention from the perspectives of streamlining the manufacturing process and recyclability, and are widely used in fields such as automobile parts, home appliances, medical device parts, electric wires, and miscellaneous goods. In particular, such thermoplastic elastomer compositions have been widely used as sealing materials for automobiles and building materials.

[0003] Components used in sealing materials for automobiles and building materials have complex structures, and the desired components are manufactured by joining components together. To join components together, a technique of joining them via a joining member is known instead of using a liquid or glue-like adhesive.

[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 a dynamically crosslinked thermoplastic elastomer together (see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-131722 [Patent Document 2] Japanese Patent Publication No. 2020-125442 Summary of the Invention [Problem to be solved by the invention]

[0006] Composite moldings used as sealing materials for window frames of automobiles and the like are obtained by fusing a joining member and a joined member at their joining surfaces. For these composite moldings, there is a demand for technology that achieves both high levels of fusion durability and sliding properties in order to prevent abnormal noise and wear that accompanies repeated raising and lowering of the window.

[0007] The joining members made of the thermoplastic elastomer compositions described in Patent Documents 1 and 2 have good sliding properties and good fusion properties with the joined members. However, when the joining member is bent from the interface between the joining member and the joined members at the fusion bonded portion, the joining member easily peels off from the interface, which leaves room for improvement in the fusion durability at the fusion bonded portion between the joining member and the joined members.

[0008] As described above, up to now, there has been no thermoplastic elastomer composition provided that combines high levels of fusion durability and sliding properties and is excellent as a joining member for composite molded articles for automobiles.

[0009] The object of the present invention is to solve the above-mentioned problems of the conventional technology and to provide a crosslinked thermoplastic elastomer composition from which a composite molded article having excellent fusion durability and sliding properties can be formed, a joining member made of this crosslinked thermoplastic elastomer composition, and an automotive composite molded article and an automotive corner material that include this joining member. [Means for solving the problem]

[0010] The present inventors have discovered a novel finding, which was not previously known, that a crosslinked thermoplastic elastomer composition obtained by melt-kneading a material composition containing component (A): a styrene-based elastomer, component (B): an unmodified polypropylene, component (C): a modified polypropylene having a modification rate of 1.0 mass % or more with maleic acid and / or its derivatives, and component (D): a lubricant, in the presence of component (f): a crosslinking agent, or a crosslinked thermoplastic elastomer composition containing components (A), (B), (C), and (D) and having a tensile stress at break of 7 MPa or more and less than 15 MPa, measured at 23°C in accordance with the ISO 37 Type 1A (test speed: 500 mm / min) tensile stress at break method, has excellent fusion durability and can achieve a high level of sliding properties, and have found that this finding can solve the above-mentioned problems, thereby completing the present invention.

[0011] That is, the gist of the present 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): Component (A): Styrene-based elastomer Component (B): Unmodified polypropylene Component (C): Modified polypropylene having a modification rate of 1.0% by mass or more with maleic acid and / or its derivatives Component (D): Lubricant Component (f): Crosslinking agent

[0013] [2] A crosslinked thermoplastic elastomer composition comprising the following components (A), (B), (C), and (D), and having a tensile stress at break of 7 MPa or more but less than 15 MPa 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). Component (A): Styrene-based elastomer Component (B): Unmodified polypropylene Component (C): Modified polypropylene having a modification rate of 1.0% by mass or more with maleic acid and / or its derivatives Component (D): Lubricant

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

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

[0016] [5] A composite molded body for an automobile, comprising the joining member described in [4].

[0017] [6] An automobile corner material using the composite molding described in [5]. [Effects of the Invention]

[0018] According to the present invention, it is possible to provide a crosslinked thermoplastic elastomer composition that can be used to mold a composite molded article having excellent fusion durability and sliding properties, a joining member made of this crosslinked thermoplastic elastomer composition, and a composite molded article for an automobile and a corner material for an automobile that include this joining member. A joining member made of the crosslinked thermoplastic elastomer composition of the present invention is useful as a joining member for sealing materials for automobiles and sealing materials for building materials, and is particularly useful as a joining member for composite molded articles for automobiles such as glass run channels, particularly composite molded articles for automobiles as corner materials for automobiles. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a perspective view showing an example of an automotive glass run channel to which the present invention is applied. DETAILED DESCRIPTION OF THE INVENTION

[0020] The present invention will be described in detail below, but the present invention is not limited to the following description and can be modified as desired without departing from the gist of the present invention. In this specification, when a numerical value or physical property value is enclosed by "~", the value before and after the "~" is used to include the values ​​before and after the "~"

[0021] [Crosslinked 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): Component (A): Styrene-based elastomer Component (B): Unmodified polypropylene Component (C): Modified polypropylene having a modification rate of 1.0% by mass or more with maleic acid and / or its derivatives Component (D): Lubricant Component (f): Crosslinking agent

[0022] The crosslinked thermoplastic elastomer composition of the present invention is also a crosslinked thermoplastic elastomer composition comprising the following components (A), (B), (C), and (D), and having a tensile stress at break of 7 MPa or more and less than 15 MPa, 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). Component (A): Styrene-based elastomer Component (B): Unmodified polypropylene Component (C): Modified polypropylene having a modification rate of 1.0% by mass or more with maleic acid and / or its derivatives Component (D): Lubricant The tensile stress at break is related to the crosslinking state of a thermoplastic elastomer composition. The tensile stress at break of a non-crosslinked thermoplastic elastomer composition tends to be high, while that of a crosslinked thermoplastic elastomer composition tends to be low. The reason why the tensile stress at break of a crosslinked thermoplastic elastomer composition tends to be low is that the crosslinked portions present in the crosslinked thermoplastic elastomer composition do not stretch, and stress is more concentrated in the non-crosslinked portions, promoting slippage between molecular chains and facilitating the formation of voids, which can lead to fracture. In other words, the interface between the rubber and resin portion of a crosslinked thermoplastic elastomer composition is weaker than that of a non-crosslinked thermoplastic elastomer, which tends to result in a low stress at break.

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

[0024] The reason why the crosslinked thermoplastic elastomer composition of the present invention exhibits such effects is not clear in detail, but is thought to be as follows. It is believed that the crosslinked thermoplastic elastomer composition of the present invention has improved fusion durability due to the presence of polar groups derived from maleic acid and / or its derivatives (component (C)) on the surface of the crosslinked thermoplastic elastomer composition, which promotes molecular entanglement at the adhesion surface with the workpieces during heat fusion bonding. In other words, good fusion durability can be obtained by using unmodified polypropylene with a high degree of maleic acid modification. If the only purpose is to improve sliding properties, it is sufficient to compound a large amount of the lubricant component (D), but this will result in a decrease in fusion durability. In the crosslinked thermoplastic elastomer composition of the present invention, components (B) and (C) have a common polypropylene main chain, and therefore components (B) and (C) are compatible with each other. This is thought to result in excellent sliding properties due to the high surface smoothness derived from the polypropylene portions of components (B) and (C) being maintained. The crosslinked thermoplastic elastomer composition of the present invention is suitable because it easily exhibits the effects of the above mechanism by controlling the structure to have a domain matrix structure in which a matrix portion containing components (B), (C), and (D) has a domain portion of component (A).

[0025] [Component (A)] The component (A) used in the present invention is a styrene-based elastomer.

[0026] The styrene-based elastomer is preferably a block copolymer having at least two polymer blocks 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 a hydrogenated product of the block copolymer. Hereinafter, this block copolymer and / or its hydrogenated product may be referred to as a "(hydrogenated) block copolymer."

[0027] Here, the term "mainly composed of" means that the target monomer unit is contained in the target polymer block in an amount of 50 mol % or more.

[0028] The aromatic vinyl compound constituting the block P is not particularly limited, and examples thereof 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 viewpoints of availability and productivity. Styrene is more preferred.

[0029] The block P may be composed of one type of aromatic vinyl compound unit or two or more types of aromatic vinyl compound units, and may contain a monomer unit other than the vinyl aromatic compound unit.

[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. 1,3-butadiene is more preferred.

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

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

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

[0034] P-(QP)m (1) (PQ)n (2) In the formula, P represents block P. Q represents block Q. m represents an integer of 1 to 5. n represents an integer of 2 to 5. When a plurality of blocks P and a plurality of blocks Q are present, the monomer units contained therein may be the same or different.

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

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

[0037] Component (A) used in the present invention may be a hydrogenated product of a block copolymer having a block P and a block Q. In this case, the hydrogenated product is preferably a block copolymer represented by formula (1), more preferably a block copolymer represented by formula (1) in which m is 3 or less, even more preferably a block copolymer represented by formula (1) in which m is 2 or less, and particularly preferably a block copolymer represented by formula (1) in which 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, and even more preferably 170,000 or more, as a polystyrene-equivalent value measured by gel permeation chromatography (hereinafter sometimes abbreviated as GPC), and is preferably 600,000 or less, more preferably 550,000 or less, and even more preferably 500,000 or less.

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

[0040] Commercially available products of component (A) include, for example, "TAIPOL (registered trademark)-6151" and "TAIPOL (registered trademark)-6159" manufactured by Taiwan Synthetic Rubber Corporation (TSRC), "G1651" and "G1633" manufactured by Kraton Polymer Japan Co., Ltd., and "Septon (registered trademark) 4099" manufactured by Kuraray Co., Ltd.

[0041] The component (A) may be used alone or in combination of two or more types with different compositions or physical properties.

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

[0043] In the present invention, "polypropylene" means one having a propylene unit content of 50% by mass or more, and includes one made of a single resin component and one made of multiple resin components. The propylene unit content of the unmodified polypropylene of 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 equal to or greater than the lower limit, heat resistance and rigidity tend to be improved. The propylene unit content of component (A) can be determined by infrared spectroscopy.

[0044] Component (B) may be a propylene homopolymer or 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, etc., preferably in an amount of 15 mass% or less, more preferably 10 mass% or less, and even more preferably 6 mass% or less.

[0045] Examples of the α-olefin unit 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, and 2,2,4-trimethyl-1-pentene. Preferred are α-olefins having 4 to 10 carbon atoms, and more preferred are 1-butene, 1-hexene, and 1-octene. The propylene copolymer may contain only one of these α-olefin units and ethylene units, or may contain two or more of them.

[0046] Specific examples of the 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 a first step and subsequently polymerizing a propylene-ethylene copolymer in a second step. Preferred are propylene-ethylene copolymers.

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

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

[0049] When 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) + ... + w1log(MFRi) + ... + wnlog(MFRn) ... (I) In formula (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] The melting peak temperature of component (B) is preferably observed at least at 100°C or higher and lower than 157°C. It is preferable that the melting peak of component (B) is at least within the above numerical range from the viewpoint of heat resistance and compatibility with component (A). The melting peak temperature of component (B) can be measured by the following method in accordance with JIS K7121. That is, the melting behavior of polypropylene is measured by carrying out the following steps (1) to (3) in order using a differential scanning calorimeter (DSC6220 manufactured by SSI NanoTechnology Inc.). In each step, a melting curve is obtained by plotting time on the horizontal axis and heat of fusion on the vertical axis, and the peak top of the peak observed in step (3) is taken as the melting peak temperature. Step (1): 5 mg of a sample is heated from room temperature to 40°C to 200°C at a rate of 100°C / min, and after the temperature increase is complete, the sample is held for 3 minutes. Step (2): The temperature is lowered from 200°C to 40°C at a rate of 10°C / min, and after the temperature drop is complete, the temperature is maintained at this temperature for 3 minutes. Step (3): The temperature is increased from 40°C to 200°C at a rate of 10°C / min.

[0051] The unmodified polypropylene of component (B) can be produced by a known polymerization method using a known olefin polymerization catalyst. For example, a multi-stage polymerization method using a Ziegler-Natta catalyst can be used. The multi-stage polymerization method can be a slurry polymerization method, a solution polymerization method, a bulk polymerization method, a gas phase polymerization method, or the like, or a combination of two or more of these methods.

[0052] Component (B) may be a commercially available product, which can be procured from the manufacturers listed below and can be selected appropriately. Available commercial products include, for example, Prim Polypro® from Prime Polymer, Sumitomo Noblen® from Sumitomo Chemical, polypropylene block copolymer from SunAllomer, Novatec® PP from Japan Polypropylene, Moplen® from LyondellBasell, Vistamaxx® from ExxonMobil, ExxonMobil PP, 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 Corporation.

[0053] The component (B) may be used alone or in combination of two or more types with different compositions or physical properties.

[0054] [Component (C)] The component (C) used in the present invention, a modified polypropylene (hereinafter sometimes referred to as "maleic acid-modified polypropylene") that has been modified with maleic acid and / or a derivative thereof and has a modification rate with maleic acid and / or a derivative thereof (hereinafter sometimes referred to as "maleic acid modification rate") of 1.0 mass% or more, functions as an improver for improving the fusion durability of the crosslinked thermoplastic elastomer resin composition of the present invention with members to be joined during heat fusion bonding.

[0055] The lower limit of the maleic acid modification rate of component (C) used in the present invention must be 1.0 mass% or more, preferably 1.1 mass% or more, and more preferably 1.2 mass% or more, based on the total amount of modified polypropylene of component (C), from the viewpoint of obtaining high fusion durability. If the maleic acid modification rate is less than 1.0% by mass relative to the total amount of modified polypropylene of component (C), sufficient fusion durability cannot be obtained. On the other hand, the upper limit of the maleic acid modification rate of component (C) is not particularly limited, but from the viewpoint of ensuring thermal stability and compatibility with other components, it is usually 5.0% by mass or less, preferably 4.5% by mass or less, and more preferably 4.0% by mass or less, relative to the total amount of modified polypropylene of component (C).

[0056] The modification rate (graft rate) herein means the content of maleic acid and / or its derivatives when measured with an infrared spectrometer. For example, the absorption characteristic of maleic acid and / or its derivatives in a sample press-molded into a sheet having a thickness of about 100 μm, specifically, 1900 to 1600 cm -1 The modification rate (graft rate) can be determined by measuring the carbonyl characteristic absorption (C=O stretching vibration band) of the maleic acid and / or its derivatives. Note that in some cases, the modification with maleic acid and / or its derivatives is not 100% subjected to the reaction, and maleic acid and / or its derivatives that have not reacted with polypropylene remain in the modified polypropylene. However, the modification rate (graft rate) in the present invention means the value measured by the above method.

[0057] The density of the maleic acid-modified polypropylene of component (C) is not particularly limited, but is preferably 0.85 g / cm when measured in accordance with ISO 1183 Method A (water displacement method). 3 More preferably, 0.87 g / cm 3 or more, while 0.96 g / cm 3 Preferably, it is 0.95 g / cm or less, more preferably 0.95 g / cm 3 The following is the result. The melt flow rate (MFR) of the maleic acid-modified polypropylene of component (C) 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 maleic acid-modified polypropylene refers to a value measured in accordance with JIS K7210:1999 under conditions of 180°C and a load of 21.2 N.

[0058] The polypropylene used as the raw material for component (C) can be the unmodified polypropylene used in component (B). Among these, propylene homopolymer and propylene-ethylene random copolymer are preferred because they are relatively inexpensive and easily available, and propylene homopolymer is more preferred from the viewpoint of obtaining high adhesiveness due to the molecular entanglement effect at the bonding surface with the joined members during heat fusion.

[0059] The density of the polypropylene used as the raw material for component (C) (based on ISO1183 Method A (water displacement method)) is not particularly limited, but is preferably 0.85 g / cm 3 More preferably, 0.87 g / cm 3 or more, while 0.96 g / cm 3 Preferably, it is 0.95 g / cm or less, more preferably 0.95 g / cm 3 The following is the result.

[0060] The melt flow rate (MFR, conforming to JIS K7210:1999, 230°C, load 21.2N) of the polypropylene used as the 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, more preferably 0.1 to 80 g / 10 min.

[0061] Propylene homopolymers, propylene-α-olefin copolymers, and other propylene copolymers that satisfy the above physical properties are commercially available in a wide variety of grades from manufacturers both in Japan and overseas, and various grades of commercially available polypropylene can be used as the raw material for component (C).

[0062] The maleic acid-modified polypropylene of component (C) is the above-mentioned polypropylene modified with maleic acid and / or its derivatives. Examples of maleic acid derivatives include maleic anhydrides, esters, amides, imides, and metal salts. Specific examples include maleic anhydride, maleic acid monoethyl ester, maleic acid diethyl ester, maleic acid monoamide, maleic acid diamide, maleic acid-N-monoethylamide, maleic acid-N,N-diethylamide, maleic acid-N-monobutylamide, maleic acid-N,N-dibutylamide, maleic acid-methyl maleate, ethyl maleate, glycidyl maleate, sodium maleate, and potassium maleate, but are not limited thereto.

[0063] The maleic acid and / or its derivatives may be used singly or in any suitable combination of two or more in any ratio. Among these, maleic acid, maleic anhydride, and maleic acid esters are preferred, and maleic acid, maleic anhydride, and glycidyl maleate are more preferred.

[0064] The amount of maleic acid and / or its derivatives used to modify polypropylene may be any amount that allows the aforementioned maleic acid modification rate to be obtained, and is usually 20 parts by mass or less, preferably 10 parts by mass or less, per 100 parts by mass of polypropylene used as the raw material for component (C). When the amount of maleic acid and / or its derivatives used is not more than the above-mentioned upper limit, the generation of unreacted substances and by-products is suppressed, and therefore, in a molded product using the obtained crosslinked thermoplastic elastomer composition, deterioration of the product appearance due to fisheyes, bumps, etc. can be prevented, and a decrease in adhesion tends to be suppressed.

[0065] The modification with maleic acid and / or a derivative thereof is preferably graft modification, and the graft modification can be carried out by various conventionally known methods, including, but not limited to, a melt modification method in which maleic acid and / or a derivative thereof is added to molten polypropylene and graft copolymerized, a solution modification method in which maleic acid and / or a derivative thereof is added to polypropylene dissolved in a solvent and graft copolymerized, and a solid-state polymerization method in which maleic acid and / or a derivative thereof is added to solid polypropylene and graft copolymerized.

[0066] Examples of melt modification methods include melting polypropylene and maleic acid and / or its derivatives using an extruder or the like at a temperature above the melting point of the polypropylene (e.g., 170 to 290°C) and reacting for typically 0.5 to 10 minutes. A preferred solution modification method involves adding polypropylene, maleic acid and / or its derivatives, and, if necessary, a radical initiator, to an organic solvent and reacting for typically 0.5 to 15 hours, preferably 1 to 10 hours, at a temperature above the melting point of the polypropylene (e.g., 170 to 290°C). A preferred solid-phase polymerization method involves adding solid polypropylene, maleic acid and / or its derivatives, and, if necessary, a radical initiator, and reacting for typically 1 to 24 hours, preferably 1 to 10 hours, at a temperature below the melting point of the polypropylene (e.g., 20 to 150°C). Among these, melt modification and solid-phase polymerization methods, which do not require the use of a solvent, are preferred from the standpoint of hygiene. For efficient graft modification, modification in the presence of a radical initiator is preferred.

[0067] The radical initiator is not particularly limited, but is preferably an organic peroxide or an azo compound, and particularly preferably an organic peroxide. 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)hexyne-3, 1,4-bis(t-butylperoxyisopropyl)benzene, 1,1-bis(t-butylperoxy)cyclohexane, n-butyl-4,4-bis(t-butylperoxy)valerate, 2,2-bis(4,4-t-butylperoxycyclohexyl)propane, 2,2-bis(t-butylperoxy)butane, and 1,1-bis(t-butylperoxy)cyclododecane; t-butyl peroxyacetate, t-butylperoxy-2-ethylhexanoate, t-butyl peroxypivalate, t-butyl peroxylaurate, t-butyl peroxybenzoate, t-butylperoxyisopropyl peroxyesters such as dibenzoyl carbonate, t-butyl peroxymaleic acid, di-t-butylperoxyisophthalate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexyne-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, but are not particularly limited to these. The radical initiator may be used alone or in combination of two or more kinds in any ratio.

[0068] Among these, radical initiators having a decomposition temperature of 100°C or higher with a half-life of 1 minute are preferred from the viewpoint of graft modification efficiency. Specifically, di-t-butyl peroxide, dicumyl peroxide, dialkyl peroxides such as 2,5-dimethyl-2,5-di(t-butylperoxy)hexane and 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3 are preferred. Preferred are peroxides, or peroxyesters such as t-butyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, and 2,5-dimethyl-2,5-di(benzoylperoxy)hexyne-3.

[0069] The amount of radical initiator used is not particularly limited, but is preferably 0.001 part by mass or more and 1 part by mass or less per 100 parts by mass of polypropylene as a raw material.

[0070] In the crosslinked thermoplastic elastomer composition of the present invention, the maleic acid-modified polypropylene of component (C) may be used alone or in combination of two or more kinds.

[0071] As a commercially available product of component (C), for example, the Modic (registered trademark) series manufactured by Mitsubishi Chemical Corporation can be appropriately used.

[0072] [Component (D)] As the lubricant of component (D), a silicone-based lubricant can be suitably used, for example, silicone oil, silicone masterbatch, and liquid siloxane wax, with silicone oil being more preferred.

[0073] [Component (E)] The thermoplastic elastomer composition of the present invention may contain a softener 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 suitable. Examples of hydrocarbon-based rubber softeners include mineral oil-based softeners and synthetic resin-based softeners, with mineral oil-based softeners being preferred in terms of compatibility with other components. Mineral oil-based softeners are generally mixtures of aromatic hydrocarbons, naphthenic hydrocarbons, and paraffinic hydrocarbons. Those in which 50% or more of the carbon atoms are paraffinic hydrocarbons are called paraffinic oils, those in which 30-45% of the carbon atoms are naphthenic hydrocarbons are called naphthenic oils, and those in which 35% or more of the carbon atoms are aromatic hydrocarbons are called aromatic oils. Of these, paraffinic oils are preferred in the present invention.

[0075] The kinematic viscosity of the softener of component (E) at 40°C is not particularly limited, but is preferably 20 cSt or more, more preferably 50 cSt or more, and is 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 softener of component (E) is commercially available, for example, the "Nippon Oil Polybutene (registered trademark) HV" series manufactured by JX Nippon Oil & Energy Corporation and the "Diana (registered trademark) Process Oil PW" series manufactured by Idemitsu Kosan Co., Ltd., from which an appropriate product can be selected and used.

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

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

[0079] The crosslinking agent may be an organic peroxide, a phenol resin, or other crosslinking aid, etc. These crosslinking agents may be used alone or in combination of two or more.

[0080] As the organic peroxide that can be used as the crosslinking agent, either an aromatic organic peroxide or an aliphatic organic peroxide can be used. Specific 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-hexyne, 1,3-bis(t-butylperoxyisopropyl)benzene, and 1,1-di(t-butylperoxy)-3,3,5-trimethylcyclohexane; peroxy esters 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-hexyne; 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 alone or in combination of two or more.

[0081] Examples of phenol resins that can be used as crosslinking agents include alkylphenol formaldehyde, brominated alkylphenol formaldehyde, etc. These phenol resins may be used alone or in combination of two or more.

[0082] Examples of crosslinking aids other than those for 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 anhydride, 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 alone or in combination of two or more.

[0083] [Other ingredients] In producing the crosslinked thermoplastic elastomer composition of the present invention, other components may be used as raw materials in addition to the components (A) to (E) and (f), as needed, within the range that does not impair the effects of the present invention.

[0084] Examples of other components include resins such as thermoplastic resins and elastomers other than component (A), component (B), and component (C), as well as various additives such as antioxidants, fillers, heat stabilizers, light stabilizers, ultraviolet absorbers, neutralizing agents, antifogging agents, antiblocking agents, slip agents, dispersants, colorants, flame retardants, antistatic agents, conductivity imparting agents, metal deactivators, molecular weight modifiers, antibacterial agents, antifungal agents, and fluorescent brighteners. Any of these may be used alone 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 homopolymers and polyoxymethylene copolymers; 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 phenol-based antioxidants, phosphite-based antioxidants, and thioether-based antioxidants. When an antioxidant is used, it is generally 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 of component (A). Within this range, good thermal stability can be obtained.

[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 hardness with sufficient flexibility, 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), from the viewpoint of sufficiently improving the effect of fusion bonding to a thermoplastic elastomer composition containing a propylene-based resin as a sea phase. From the viewpoint of improving compression set, 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. On the other hand, from the viewpoint of ensuring flowability, 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.

[0089] The crosslinked thermoplastic elastomer composition of the present invention typically contains 0.5 to 50 parts by mass, preferably 1 to 25 parts by mass, of component (D) per 100 parts by mass of component (A). By adding component (D) in a small amount, more preferably 20 parts by mass or less 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 adhesion.

[0090] In the crosslinked thermoplastic elastomer composition of the present invention, the lower limit of the amount of the crosslinking agent of 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 sufficiently progressing crosslinking. On the other hand, the upper limit of the amount of the crosslinking agent of 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 propylene chains.

[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 the 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, per 100 parts by mass of components (A) and (B) combined (however, if component (E) is contained, the content of components (A), (B), and (E) combined 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, per 100 parts by mass of components (A) and (B) combined (however, if component (E) is contained, the content of components (A), (B), and (E) combined is 100 parts by mass or more).

[0093] [Method of producing crosslinked thermoplastic elastomer composition] The crosslinked thermoplastic elastomer resin composition of the present invention is obtained by dynamic heat treatment in which a material composition for a crosslinked thermoplastic elastomer composition containing components (A), (B), (C), and (D) is melt-kneaded in the presence of component (f). More preferably, the crosslinked thermoplastic elastomer resin composition is obtained by dynamic heat treatment in which a material composition containing components (A), (B), (C), (D), and (E) is melt-kneaded 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 examples of melt kneading devices that can be used for this purpose include a closed-type Banbury mixer, a mixing roll, a kneader, and a twin-screw extruder. Among these, it is preferable to use a twin-screw extruder. A preferred embodiment of the production method using this twin-screw extruder is to supply each component to a raw material supply port (hopper) of a twin-screw extruder having multiple raw material supply ports and then perform dynamic heat treatment.

[0095] The temperature when the dynamic heat treatment is carried out is usually 80 to 300° C., and preferably 100 to 250° C. The time for which the dynamic heat treatment is carried out is usually 0.1 to 30 minutes.

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

[0097] For efficient production of the thermoplastic elastomer composition, it is preferable that the above relationship between the barrel radius (R (mm)), screw rotation speed (N (rpm)), and discharge rate (W (kg / h)) of the twin-screw extruder is greater than the above lower limit. On the other hand, it is preferable that the above relationship is smaller than the above upper limit, since heat generation due to shearing is suppressed and foreign matter that causes poor appearance is less likely to be generated.

[0098] [Physical properties of crosslinked thermoplastic elastomer composition] 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 at a temperature of 230°C and a load of 21.2 N according to a method in accordance with JIS K7210. 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 / cm as measured in accordance with ISO 1183 Method A (underwater displacement method). 3 It is preferably 1.00 g / cm or less, and more preferably 1.00 g / cm 3 More preferably, it is 0.97 g / cm or less. 3 The lower limit of density is generally 0.90 g / cm3 based on the density of polypropylene. 3 That's all.

[0100] From the viewpoint of application as a joining member, the crosslinked thermoplastic elastomer composition of the present invention preferably has a Duro A hardness, measured in accordance with ISO 7619, 15 seconds after pressing a needle against a test piece, of 35 to 98, more preferably 40 to 95.

[0101] From the viewpoint of use as a joining member, the crosslinked thermoplastic elastomer composition of the present invention preferably has a lower limit of 7 MPa or more, more preferably 8 Pa or more, and even more preferably 9 MPa or more, in terms 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). The upper limit of the tensile stress at break is usually less than 15 MPa, more preferably 14 MPa or less, and even more preferably 13 MPa or less.

[0102] From the viewpoint of use as a joining member, the crosslinked thermoplastic elastomer composition of the present invention preferably has a lower limit of the elongation at break value measured according to a procedure in accordance with the method for measuring elongation at break of ISO 37 Type 1A (test speed 500 mm / min) of 400% or more, more preferably 500% or more, and even more preferably 600% or more. The upper limit of the elongation at break value 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 usually used for crosslinked thermoplastic elastomer compositions, such as injection molding, extrusion molding, blow molding, and compression molding, among which injection molding is preferred. Furthermore, the crosslinked thermoplastic elastomer composition can also be molded into a molded article by performing secondary processing such as lamination molding and thermoforming after the molding.

[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, weather strips, ceiling materials, interior sheets, bumper moldings, side moldings, air spoilers, air duct hoses, and sealants; civil engineering and building material parts such as waterproofing materials, joint materials, window frames, and sealants; sporting goods 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 parts such as containers and packings; medical equipment parts; electric wires; and miscellaneous goods. The molded article made of the crosslinked thermoplastic elastomer composition of the present invention is suitable as a sealing material for automobiles and a sealing material for building materials, among the above-mentioned, and is suitable as a sealing material for automobiles, particularly as a glass run channel for automobiles.

[0105] [Joining material] The joining member of the present invention is made of the above-mentioned crosslinked thermoplastic elastomer composition of the present invention, and is produced by melt-kneading the crosslinked thermoplastic elastomer composition of the present invention and injection-molding the resulting melt-kneaded product.

[0106] The joining member of the present invention is particularly suitable as a joining member used in composite molded articles for automobiles, such as glass run channels for automobiles. 1 is a perspective view showing an example of an automotive glass run channel as a composite molded product 3. This composite molded product 3 is obtained by fusion-integrating joined members 1A and 1B constituting linear portions separately produced by extrusion molding of a thermoplastic elastomer composition at corner portions which are joining members 2 made of the cross-linked thermoplastic elastomer composition of the present invention.

[0107] Such a composite molded body 3 can be produced, for example, by inserting the joining end sides of pre-fabricated joined members 1A and 1B into an injection molding die, and then injecting the cross-linked thermoplastic elastomer composition of the present invention into the die to form joining members 2 at the corners, and fusing and integrating them with the end faces of the joined members 1A and 1B. [Example]

[0108] The present invention will be described in more detail below 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 invention. The values ​​of various production conditions and evaluation results in the following examples represent preferred upper or lower limit values ​​in the embodiments of the present invention, and preferred ranges may be defined by combining the above-mentioned upper or lower limit values ​​with the values ​​in the following examples or values ​​between the examples.

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

[0110] [Component (A): Styrene-based 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): 30 g / 10 min (230°C, 21.2 N), melting peak temperature: 155°C, propylene unit content: 98% by mass, ethylene unit content: 2% by mass) / Japan Polypropylene Corporation, "Novatec (registered trademark) PP MG03BD"

[0112] [Component (C): Maleic acid-modified polypropylene] <c-1> Maleic acid-modified polypropylene C-1 produced as follows: MFR (JIS K7210): 14 g / 10 min (180°C, load 21.2 N), modification rate: 1.2 mass% Commercially available homopolypropylene (polypropylene homopolymer) (density: 0.90 g / cm 3 To 5 kg of a maleic acid-modified polypropylene (MFR (JIS K7210): 0.6 g / 10 min (230°C, load 21.2 N)), 200 g of maleic anhydride and 40 g of an organic peroxide (NOF Corporation's "Perbutyl I") were added and mixed, and the mixture was fed into a twin-screw extruder previously set at 230°C, melt-mixed, and strand-cut to obtain pellets of maleic acid-modified polypropylene C-1. <C´-1> Maleic acid-modified polypropylene C'-1 produced as follows: MFR (JIS K7210): 47 g / 10 min (180°C, load 21.2 N), modification rate: 0.8 mass% Commercially available homopolypropylene (polypropylene homopolymer) (density: 0.90 g / cm 3 100 g of maleic anhydride and 130 g of organic peroxide ("Perbutyl O" manufactured by NOF Corporation) were added to 5 kg of maleic acid-modified polypropylene (MFR (JIS K7210): 0.6 g / 10 min (230°C, load 21.2 N)) and mixed. The mixture was fed into a twin-screw extruder pre-set to 230°C, melt-mixed, and strand-cut to obtain pellets of maleic acid-modified polypropylene C'-1.

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

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

[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 / "Divinylbenzene" crosslinking aid manufactured by Wako Pure Chemical Industries, Ltd.

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

[0117] [Evaluation method] The crosslinked thermoplastic elastomer compositions in the following examples and comparative examples were evaluated as follows.

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

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

[0120] (2) Density: Measured according to ISO1183 Method A (underwater displacement method).

[0121] (3) Tensile stress at break: This was performed at 23°C using a procedure that conforms to the method for measuring tensile stress at break of ISO37 Type 1A (test speed 500 mm / min).

[0122] (4) Elongation at break: This was performed according to the procedure for measuring elongation at break of ISO37 Type 1A (test speed 500 mm / min).

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

[0124] (6) Evaluation of the fusion method with a thermoplastic elastomer composition containing a propylene-based resin as a sea phase and fusion durability (bending test) A 1 mm-thick injection-molded sheet of a thermoplastic elastomer composition containing a propylene-based resin as a sea phase ("TREXPRENE® 3855N," a dynamically crosslinked thermoplastic elastomer manufactured by Mitsubishi Chemical Corporation) was cut into a 10 cm x 5 cm piece 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, and composite molded articles were obtained by insert molding. The composite molded articles were punched into JIS K7195 heat-sag dumbbells (25 mm wide x 150 mm long) and subjected to a bending test at a rate of one bending cycle per second, with each set consisting of 180° bending to the left and right around the fused interface. The number of bending cycles required to develop cracks at the fused interface was recorded for a total of three test specimens, and the average value was calculated. A higher average value indicates better fusion durability. In this evaluation, the upper limit of the number of times that the sample could be bent was set to 100. In the table, 100 indicates that no cracks occurred even after 100 bends. This evaluation is an evaluation of fusion durability using an injection-molded sheet, and the results of this evaluation make it possible to accurately evaluate the fusion durability when a composite molded product such as that shown in Figure 1 is formed.

[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 material composition was obtained by blending 100 parts by weight of (A-1), 100 parts by weight of (B-1), 16.7 parts by weight of (C-1), 10 parts by weight of (D-1), 133 parts by weight of (E-1), 2.0 parts by weight of (f-1) (a mixture of 40 parts by weight of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane and 60 parts by weight of calcium carbonate), 2.0 parts by weight of (f-2) (a mixture of 55 parts by weight of divinylbenzene and 45 parts by weight of ethylvinylbenzene), and 0.33 parts by weight of (G-1) in a Henschel mixer for 1 minute. This material composition was fed into the feed section of a co-rotating twin-screw extruder (Japan Steel Works, Ltd., "TEX30α", L / D = 46, number of cylinder blocks: 13) at a total rate of 15 kg / h and melt-kneaded at a temperature ranging from 110 to 220 °C to obtain pellets of the crosslinked thermoplastic elastomer composition. The melt flow rate (MFR) of the resulting crosslinked thermoplastic elastomer composition was measured at a temperature of 230°C and a load of 21.2 N according to the method of JIS K7210, and the above-mentioned evaluations (1) to (7) were also carried out. The evaluation results are shown in Table 1.

[0127] <Comparative Examples 1 and 2> Pellets of a crosslinked thermoplastic elastomer composition were obtained in the same manner as in Example 1, except that the blending ratios were as shown in Table 1. 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, the amount of component (f-1) is not shown as the actual amount, but as the amount of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane alone (40% by mass of the actual amount) of component (f-1), and the amount of component (f-2) is not shown as the actual amount, but as the amount of divinylbenzene alone (55% by mass of the actual amount) of component (f-2). In addition, in Table 1, the component (G-1) is omitted.

[0129] [Table 1]

[0130] <Evaluation results> As shown in Table 1, the crosslinked thermoplastic elastomer composition of Example 1 is excellent in fusion durability and sliding properties. Comparative Example 1 is an example in which component (C) was not used, and the fusion durability was poor. Comparative Example 2, in which component (C') was used instead of component (C), exhibited poor fusion durability. This is believed to be because the modification rate of component (C') was 0.8% by mass, and the number of polar groups derived from maleic acid present on the surface of the crosslinked thermoplastic elastomer composition was small, resulting in insufficient molecular entanglement at the adhesive surface with the workpieces during heat fusion. [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 building materials such as waterproofing materials, joint materials, window frames, and sealants; sporting goods such as golf club grips and tennis racket grips; industrial parts such as hoses and gaskets; home appliance parts such as hoses and packings; medical parts such as medical containers, gaskets, and packings; food parts such as containers and packings; medical equipment parts; electric wires; and miscellaneous goods. Among the above, the crosslinked thermoplastic elastomer composition of the present invention is particularly suitable as an automotive sealant and a building sealant, and is particularly suitable as an automotive sealant for automotive corners, particularly as an automotive glass run channel. [Explanation of symbols]

[0132] 1A,1B Parts to be joined 2. Joint materials 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 following amounts: 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), in the presence of the following component (f). Component (A): Styrene-based elastomer Component (B): Unmodified polypropylene Component (C): Modified polypropylene having a modification rate with maleic acid and / or its derivatives of 1.0% by mass or more Component (D): Lubricant Component (f): Crosslinking agent

2. A crosslinked thermoplastic elastomer composition comprising the following components (A), (B), (C), and (D) in amounts 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), relative to 100 parts by mass of component (A), wherein the composition has a tensile stress at break of 7 MPa or more and less than 15 MPa, as 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). Component (A): Styrene-based elastomer Component (B): Unmodified polypropylene Component (C): Modified polypropylene having a modification rate with maleic acid and / or its derivatives of 1.0% by mass or more Component (D): Lubricant

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

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

5. A composite molded article for an automobile, comprising the joining member according to claim 4.

6. A corner material for an automobile, which uses the composite molding according to claim 5.

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