Thermoplastic elastomer composition and composite molded product

Abstract

A thermoplastic elastomer composition comprising the following components (A), (B1), (B2), and (C); and a composite molded object obtained using said thermoplastic elastomer composition. Provided are: a thermoplastic elastomer from which a composite molded object excellent in terms of sliding property, fusion bondability, and the durability of fusion-bonded joints can be molded; and such composite molded object. Component (A): A styrene-based elastomer Component (B1): A crystalline polypropylene Component (B2): An amorphous polypropylene Component (C): A silicone-based lubricant

Description

[Technical Field]

[0001] The present invention relates to a thermoplastic elastomer composition and a composite molded article using this thermoplastic elastomer composition. [Background technology]

[0002] Thermoplastic elastomer compositions obtained by melt-kneading a propylene-based resin and a styrene-butadiene block copolymer exhibit the properties of a rubber-like soft material, but do not require a vulcanization process and have moldability similar to that of thermoplastic resins. For this reason, 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, thermoplastic elastomer compositions have been widely used as sealing materials for automobiles and building materials.

[0003] Since automotive sealing materials have a complex structure, the desired composite molded article is usually produced by joining together molded articles made of a thermoplastic elastomer composition.

[0004] The present inventors have previously proposed a joining technology in which molded bodies, which are members to be joined, are fused together using a joining member made of a thermoplastic elastomer composition without using adhesives or the like. The thermoplastic elastomer composition is obtained by mixing a specific viscosity non-hydrogenated styrene-butadiene block copolymer, a styrene-butadiene hydrogenated block copolymer, a hydrocarbon-based rubber softener, and a propylene-based resin in a certain ratio, followed by dynamic crosslinking (Patent Document 1).

[0005] As a technique for fusing molded articles together, a method has been proposed in which molded articles obtained by profile extrusion molding of a thermoplastic elastomer composition containing a specific hydrogenated block copolymer, a specific amorphous polyolefin polymer, a polypropylene-based resin, and a mineral oil-based rubber softener in specified proportions are heat-fused together (Patent Document 2). In Patent Document 2, an amorphous polyolefin polymer is blended into the thermoplastic elastomer composition to improve heat-fusion properties.

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2019-131722 [Patent Document 2] Japanese Patent Application Publication No. 10-120865

[0007] Composite molded articles used as sealing materials for window frames in automobiles, etc., are required to have improved sliding properties to prevent abnormal noise and wear caused by repeated raising and lowering of the window. It is known that blending a highly slippery material to improve sliding properties deteriorates the fusion properties and fusion durability of the joining member, and therefore a technology that can achieve high levels of both sliding properties and fusion properties and fusion durability is desired.

[0008] The joining member made of the thermoplastic elastomer composition described in Patent Document 1 has good fusion properties with the joined members while maintaining sliding properties. 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 of the fusion bonded portion between the joining member and the joined members. The thermoplastic elastomer composition described in Patent Document 2 is not satisfactory for applications where a combination of sliding properties, fusion properties, and fusion durability is required as a joining member. Summary of the Invention

[0009] An object of the present invention is to solve the above-mentioned problems of the conventional art and to provide a thermoplastic elastomer composition from which a composite molded article having excellent sliding properties, fusion properties, and fusion durability can be molded, and a composite molded article made from this thermoplastic elastomer composition.

[0010] The present inventors have discovered that a thermoplastic elastomer composition comprising a styrene-based elastomer, a specific propylene-based resin, and a silicone-based lubricant can produce a composite molded article that is excellent in sliding properties, fusion properties, and fusion durability, and have arrived at the present invention. The present inventors have also found that a thermoplastic elastomer composition in which a styrene-based elastomer and a specific propylene-based resin have an island-sea structure, and which has a tear elongation of a predetermined value or more measured by a specific method, can also be used to realize a composite molded article having excellent sliding properties, fusion properties, and fusion durability. Furthermore, the present inventors have found that in a composite molded product comprising a joining member made of a first thermoplastic elastomer composition having an island-sea structure in which a styrene-based elastomer exists as an island phase in a sea phase of a propylene-based resin made of crystalline polypropylene and amorphous polypropylene, and a joined member made of a second thermoplastic elastomer composition containing a thermoplastic elastomer containing a propylene-based resin, the composite molded product can have excellent sliding properties, fusion properties, and fusion durability, as long as the tear elongation measured by a specific method using the first thermoplastic elastomer composition and the second thermoplastic elastomer composition is equal to or greater than a predetermined value.

[0011] That is, the gist of the present invention is as follows.

[0012] [1] A thermoplastic elastomer composition comprising the following components (A), (B1), (B2), and (C): Component (A): Styrene-based elastomer Component (B1): Crystalline polypropylene Component (B2): amorphous polypropylene Component (C): Silicone-based lubricant

[0013] [2] The thermoplastic elastomer composition according to [1], having a tear elongation of 230% or more as measured by the following method. <Method for measuring tear elongation> An injection molding die is loaded with an injection-molded sheet of a thermoplastic elastomer composition (Duro A hardness: 75-85, melting point: 133-143°C) containing a propylene-based resin as a sea phase as an insert material, and the thermoplastic elastomer composition [1] is injection-molded at 260°C to obtain a composite molded body. JIS K6252 unnotched angle dumbbell test pieces are punched out from the molded body, and the tear elongation from a distance of 20 mm between the gauge lines is measured at a test temperature of 23°C and a test speed of 200 mm / min.

[0014] [3] The thermoplastic elastomer composition according to [1] or [2], wherein the content of the component (B2) is 10% by mass or more and 30% by mass or less, when the total of the component (B1) and the component (B2) is 100% by mass.

[0015] [4] The thermoplastic elastomer composition according to any one of [1] to [3], wherein the mass ratio of the component (A) to the total mass of the components (B1) and (B2) is 1.00 or more and 1.30 or less.

[0016] [5] The thermoplastic elastomer composition according to any one of [1] to [4], which has a compression set of 55% or less, measured in accordance with JIS K6262 under conditions of 70°C, 22 hours, and 25% compression.

[0017] [6] The thermoplastic elastomer composition according to any one of [1] to [5], wherein the component (B2) has a melt flow rate (MFR) of 1 to 10 g / 10 min, measured at a measurement temperature of 230°C and a measurement load of 21.2 N.

[0018] [7] The thermoplastic elastomer composition according to any one of [1] to [6], which has an elongation at break of 950% or more as measured in accordance with JIS K6251.

[0019] [8] A joining member made of the thermoplastic elastomer composition according to any one of [1] to [7].

[0020] [9] A corner member for an automobile, comprising the joining member described in [8].

[0021]

[10] A composite molded product comprising a joining member made of a first thermoplastic elastomer composition and a joined member made of a second thermoplastic elastomer composition, wherein the first thermoplastic elastomer composition is the thermoplastic elastomer composition according to any one of [1] to [7].

[0022]

[11] A glass run channel for an automobile comprising the composite molding according to

[10] .

[0023]

[12] A thermoplastic elastomer composition having an island-sea structure in which component (A): a styrene-based elastomer exists as an island phase in a sea phase of component (B): a propylene-based resin, and the thermoplastic elastomer composition has a tear elongation of 230% or more as measured by the following method. <Method for measuring tear elongation> An injection-molded sheet of a thermoplastic elastomer composition (Duro A hardness: 75-85, melting point: 133-143°C) containing a propylene-based resin as a sea phase is loaded as an insert material into an injection molding die. The thermoplastic elastomer composition having an island-in-sea structure is injection-molded at 260°C to obtain a composite molded product. JIS K6252 unnotched angle dumbbell test pieces are punched out from the molded product. The tear elongation from a 20 mm gap between gauge marks is measured using the test pieces at a test temperature of 23°C and a test speed of 200 mm / min.

[0024]

[13] The thermoplastic elastomer composition according to

[12] , wherein the component (B) consists of component (B1): crystalline polypropylene and component (B2): amorphous polypropylene.

[0025]

[14] The thermoplastic elastomer composition according to

[13] , wherein the content of the component (B2) is 10% by mass or more and 30% by mass or less, when the total of the components (B1) and (B2) is 100% by mass.

[0026]

[15] The thermoplastic elastomer composition according to

[13] or

[14] , wherein the mass ratio of the component (A) to the total mass of the components (B1) and (B2) is 1.00 or more and 1.30 or less.

[0027]

[16] The thermoplastic elastomer composition according to any one of

[12] to

[15] , which has a compression set of 55% or less, measured in accordance with JIS K6262 under conditions of 70°C, 22 hours, and 25% compression.

[0028]

[17] A composite molded body comprising a joining member made of a first thermoplastic elastomer composition and a joined member made of a second thermoplastic elastomer composition, the first thermoplastic elastomer composition is a thermoplastic elastomer composition having a sea-island structure in which component (A): a styrene-based elastomer is present as island phases in a sea phase of component (B): a propylene-based resin, the second thermoplastic elastomer composition comprises a thermoplastic elastomer containing a propylene-based resin, A composite molded article using the first thermoplastic elastomer composition and the second thermoplastic elastomer composition has a tear elongation of 230% or more as measured by the following method. <Method for measuring tear elongation> An injection molding die is loaded with an injection-molded sheet of the second thermoplastic elastomer composition as an insert material, and the first thermoplastic elastomer composition is injection-molded at 260°C to obtain a composite molded body. A JIS K6252 unnotched angle dumbbell test piece is punched out from the composite molded body, and the tear elongation from a distance of 20 mm between benchmark lines is measured at a test temperature of 23°C and a test speed of 200 mm / min.

[0029]

[18] The composite molded body according to

[17] , wherein the component (B) comprises a component (B1): crystalline polypropylene and a component (B2): amorphous polypropylene.

[0030]

[19] The composite molding according to

[18] , wherein the content of the component (B2) is 10% by mass or more and 30% by mass or less, when the total of the component (B1) and the component (B2) is 100% by mass.

[0031]

[20] A glass run channel for an automobile, comprising the composite molding according to any one of

[17] to

[19] . [Effects of the Invention]

[0032] According to the present invention, there can be provided a thermoplastic elastomer composition capable of forming a composite molded article having excellent sliding properties, fusion properties, and fusion durability, and a composite molded article using this thermoplastic elastomer composition.

[0033] The thermoplastic elastomer composition and composite molded article of the present invention are useful as sealing materials for automobiles and building materials due to their excellent sliding properties, fusion properties, and fusion durability, and are particularly useful as composite molded articles for automobile glass run channels, etc. [Brief explanation of the drawings]

[0034] [Figure 1] FIG. 1 is a perspective view showing an example of an automotive glass run channel to which the present invention is applied. [Figure 2] FIG. 2 is a front view showing a JIS K6252 unnotched angle dumbbell test piece for measuring tear elongation. DETAILED DESCRIPTION OF THE INVENTION

[0035] The present invention will be described in detail below. The present invention is not limited to the following description, and can be practiced in any modified form without departing from the gist of the present invention. In this specification, when "~" is used to express a numerical value or a physical property value, the values ​​before and after the "~" are included.

[0036] [Thermoplastic elastomer composition] The thermoplastic elastomer composition of the present invention contains the following components (A), (B1), (B2) and (C). Component (A): Styrenic elastomer (hereinafter sometimes referred to as “styrenic elastomer (A)”) Component (B1): Crystalline polypropylene (hereinafter sometimes referred to as "crystalline polypropylene (B1)") Component (B2): Amorphous polypropylene (hereinafter sometimes referred to as "amorphous polypropylene (B2)") Component (C): Silicone-based lubricant (hereinafter sometimes referred to as “silicone-based lubricant (C)”)

[0037] The thermoplastic elastomer composition of the present invention is also a thermoplastic elastomer composition having a sea-island structure in which component (A): a styrene-based elastomer exists as island phases in a sea phase of component (B): a propylene-based resin (hereinafter, may be referred to as "propylene-based resin (B)"), and has a tear elongation of 230% or more as measured by the following method.

[0038] Whether the thermoplastic elastomer composition has the above-described sea-island structure can be confirmed by the following method. As a pretreatment step, the material to be observed is embedded in epoxy resin, and then sections are prepared using a diamond knife or similar. The sections are then stained with osmium tetroxide or ruthenium tetroxide in a desiccator. The stained sections are then observed under a transmission electron microscope. The sea and island portions of the sea-island structure are distinguished by the degree of staining of the resin by osmium tetroxide, and this is used to confirm the presence or absence of a sea-island structure. Styrene-based elastomers are stained darkly, while propylene-based resins are stained lightly.

[0039] [Method for measuring tear elongation] The method for measuring tear elongation in the present invention (hereinafter, sometimes referred to as "the method for measuring tear elongation in the present invention") will be described with reference to FIG. Hereinafter, the thermoplastic elastomer composition of the present invention used for measuring tear elongation may be referred to as the "test thermoplastic elastomer composition," and the thermoplastic elastomer composition containing a propylene-based resin as a sea phase, which is used as the counterpart material for measuring tear elongation, may be referred to as the "thermoplastic elastomer composition for insert material."

[0040] Specifically, the measurement of tear elongation according to the present invention is carried out according to the following steps (1) to (4).

[0041] (1) As a thermoplastic elastomer composition for insert material, a thermoplastic elastomer composition containing a propylene-based resin as a sea phase (Duro A hardness: 75 to 85, melting point: 133 to 143°C) is used to form an injection-molded sheet with a thickness of 2 mm, and this injection-molded sheet is cut into a size of 10 cm x 5 cm to form an insert material.

[0042] (2) This insert material is loaded into the mold of a 110-ton injection molding machine, and the test thermoplastic elastomer composition is injected into the mold at a cylinder temperature of 260°C and a mold temperature of 40°C. Using the insert molding method, a composite molded product is obtained in which the insert material and the molded sheet portion made of the test thermoplastic elastomer composition are integrally molded at the thickness portion of the sheet edge.

[0043] (3) From the composite molded product, a JIS K6252 unnotched angle dumbbell test piece 10 shown in Fig. 2 is punched out. This test piece 10 is a composite test piece having a fracture initiation point 10X at a fusion interface 10C between a thermoplastic elastomer composition for insert material part 10A containing a propylene-based resin as a sea phase (the dotted part in Fig. 2) and a test thermoplastic elastomer composition part 10B (the white part in Fig. 2). As shown in Figure 2, this test piece 10 was positioned with the thermoplastic elastomer composition part for insert material 10A at the top in the vertical direction and the thermoplastic elastomer composition part under test 10B at the bottom in the vertical direction, and benchmark lines 10a and 10b were drawn at a distance of 10 mm above and below the fused interface 10C as the center line, making the distance between the benchmark lines 20 mm in total.

[0044] (4) For this test piece 10, the thermoplastic elastomer composition portions 10A and 10B are pulled in the direction away from the fused interface 10C at a test temperature of 23°C and a test speed of 200 mm / min, and the tear elongation is measured. When measuring this tear elongation, the tear strength can also be measured.

[0045] That is, the present inventors have confirmed that evaluation of fusion durability using test pieces made from JIS No. 3 dumbbells used in general tensile tests does not adequately reproduce fusion durability. Therefore, the present inventors have conducted extensive research to evaluate fusion durability with good reproducibility, and have confirmed that the fusion durability of the thermoplastic elastomer composition used as a joining member can be evaluated with good reproducibility by measuring the tear elongation using test piece 10 in which a portion prone to fracture is formed at the fusion interface (V-groove portion 10X at fusion interface 10C in Figure 2) as described above, instead of a JIS K6252 notched angle dumbbell that has conventionally been used for tear tests of single materials.

[0046] Here, the thermoplastic elastomer composition containing a propylene-based resin as a sea phase (Duro A hardness: 75 to 85, melting point: 133 to 143°C) used as the thermoplastic elastomer composition for insert material is not particularly limited, but a commercially available product that can be used is "TREXPRENE (registered trademark) 3855N (dynamically crosslinked thermoplastic elastomer, Duro A hardness: 83, melting point: 138°C)" manufactured by Mitsubishi Chemical Corporation.

[0047] Generally, increasing the amount of the styrene-based elastomer (A), which is a rubber component, is considered as a means for improving the tear elongation, but the proportion of the propylene-based resin (B), which acts as a fusion component, decreases relatively, resulting in a decrease in fusion properties. The present inventors have found that by blending amorphous polypropylene (B2) with crystalline polypropylene (B1), it is possible to improve the tear elongation and achieve fusion durability without impairing fusion properties.

[0048] [mechanism] The reason why the thermoplastic elastomer composition of the present invention exhibits the above-mentioned effects is not clear in detail, but is presumed to be as follows. The amorphous polypropylene (B2) contained as the propylene-based resin (B) improves the dispersibility of the styrene-based elastomer (A), which is the rubber component, resulting in higher tear elongation characteristics than conventional products. As a result, less force is applied to the fused portion (fused interface) between the joining member and the joined member, improving sliding properties and providing good fusion durability.

[0049] [Styrene-based elastomer (A)] As the styrene-based elastomer (A) used in the thermoplastic elastomer composition of the present invention, known elastomers can be used.

[0050] The styrene-based elastomer (A) is preferably a block copolymer having at least two polymer blocks mainly composed of a vinyl aromatic compound and at least one polymer block containing butadiene, and / or a hydrogenated product of the block copolymer. Hereinafter, the block copolymer of component (A) and / or its hydrogenated product may be referred to as a "(hydrogenated) block copolymer."

[0051] Here, "polymer block mainly composed of a vinyl aromatic compound" means a block obtained by polymerizing a monomer mainly composed of a vinyl aromatic compound. "Polymer block containing butadiene" means a block obtained by polymerizing a monomer containing butadiene. "Mainly composed of a vinyl aromatic compound" means that the polymer contains 50 mol % or more of a vinyl aromatic compound.

[0052] The vinyl aromatic compound monomer constituting the polymer block mainly composed of a vinyl aromatic compound of component (A) is not limited, but is preferably styrene and / or a styrene derivative such as α-methylstyrene. Of these, it is preferable that the polymer block mainly be composed of styrene. The polymer block mainly composed of a vinyl aromatic compound may contain a monomer other than the vinyl aromatic compound as a raw material.

[0053] The butadiene-containing polymer block of component (A) may contain a monomer other than butadiene, such as isoprene, as a raw material.

[0054] The mass proportion of the "polymer block mainly composed of a vinyl aromatic compound" 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.

[0055] The chemical structure of the block copolymer of component (A) may be linear, branched, radial, etc. Component (A) is preferably a block copolymer represented by the following formula (I) or (II), and from the viewpoint of improving mechanical strength, the structure of the following formula (I) is more preferred.

[0056] P-(QP) m (I) (PQ) n (II) (In the formula, P represents a polymer block mainly composed of a vinyl aromatic compound, and Q represents a polymer block containing butadiene. 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 compound units may be the same or different.

[0057] In formula (I) or (II), 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.

[0058] From the viewpoint of rubber elasticity of the composition, component (A) is preferably a block copolymer represented by formula (I), more preferably a block copolymer represented by formula (I) in which m is 3 or less, even more preferably a block copolymer represented by formula (I) in which m is 2 or less, and most preferably a block copolymer represented by formula (I) in which m is 1.

[0059] Component (A) 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 (I), more preferably a block copolymer represented by formula (I) in which m is 3 or less, even more preferably a block copolymer represented by formula (I) in which m is 2 or less, and most preferably a block copolymer represented by formula (I) in which m is 1.

[0060] Examples of (hydrogenated) block copolymers having at least two polymer blocks mainly composed of vinyl aromatic compounds as component (A) and at least one polymer block containing butadiene include styrene-butadiene-styrene block copolymers and hydrogenated products thereof, and styrene-isoprene-butadiene-styrene block copolymers and hydrogenated products thereof. Among these, styrene-butadiene-styrene hydrogenated block copolymers are preferred for use as joining materials, as they have the fluidity necessary for fusion with the olefin rubbers and olefin thermoplastic elastomers used as the joined materials.

[0061] The weight average molecular weight of the styrene elastomer (A) of component (A), as a polystyrene-equivalent value measured by gel permeation chromatography (hereinafter sometimes abbreviated as GPC), is preferably 200,000 or more, more preferably 220,000 or more, and even more preferably 240,000 or more. The upper limit of the weight average molecular weight of the styrene elastomer (A) is preferably 600,000 or less, more preferably 580,000 or less, even more preferably 560,000 or less, and particularly preferably 430,000 or less from the viewpoint of fusion strength. When the weight average molecular weight of the styrene elastomer (A) is within the above range, it is possible to obtain good sliding properties while having a sufficient compression set.

[0062] The method for producing the styrene-based elastomer (A) is not particularly limited, and any method may be used as long as the above-mentioned structure and physical properties can be obtained. For example, a block copolymer can be obtained by block polymerization using a lithium catalyst or the like according to the method described in JP-A-7-97493. The block copolymer can be hydrogenated in an inert solvent in the presence of a hydrogenation catalyst according to the method described in JP-A-59-133203, for example.

[0063] Commercially available styrene-based elastomers (A) include "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.

[0064] The styrene elastomer (A) may be used alone or in combination of two or more types having different compositions or physical properties.

[0065] [Propylene-based resin (B)] The propylene-based resin (B) used in the thermoplastic elastomer composition of the present invention preferably comprises a crystalline polypropylene (B1) and an amorphous polypropylene (B2). The crystalline polypropylene (B1) is a component that mainly contributes to injection moldability. The amorphous polypropylene (B2) is a component that mainly imparts fusion properties and fusion durability to the thermoplastic elastomer composition.

[0066] In the present invention, the term "propylene-based resin" means a resin having a propylene unit content of 50% by mass or more, and includes resins consisting of a single resin component and resins consisting of multiple resin components.

[0067] The crystalline polypropylene (B1) has an ethylene unit content of less than 7% by mass relative to the total monomer units constituting the crystalline polypropylene (B1). The upper limit of the ethylene unit content is preferably 6% by mass or less, more preferably 5% by mass or less. The lower limit of the ethylene unit content of the crystalline polypropylene (B1) is preferably 1% by mass or more, more preferably 2% by mass or more. The propylene unit content of the crystalline polypropylene (B1) is usually 50% by mass or more, preferably 60 to 99% by mass, more preferably 80 to 98% by mass relative to the total monomer units constituting the crystalline polypropylene (B1).

[0068] The content of each structural unit in the crystalline polypropylene (B1) can be determined by infrared spectroscopy. The same applies to the amorphous polypropylene (B2) described below.

[0069] The crystalline polypropylene (B1) preferably has a melting peak temperature of 100° C. or more and less than 157° C. A melting peak temperature of at least the lower limit is preferred from the viewpoint of heat resistance, and a melting peak temperature of less than the upper limit is preferred from the viewpoint of compatibility with the styrene-based elastomer (A).

[0070] The melting peak temperatures of the crystalline polypropylene (B1) and the amorphous polypropylene (B2) described below can be measured by the following method in accordance with JIS K7121. Using a differential scanning calorimeter (DSC6220 manufactured by SSI NanoTechnology Inc.), the following steps (1) to (3) are carried out in order. 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.

[0071] The crystalline polypropylene (B1) is preferably a propylene-ethylene copolymer. The propylene-ethylene copolymer is a copolymer having propylene units, ethylene units, and, if necessary, structural units other than the propylene units and ethylene units. Specific examples of structural units other than the propylene units and ethylene units include α-olefin units other than propylene. Examples of other α-olefin units include 1-butene units, 1-pentene units, 1-hexene units, 1-heptene units, 1-octene units, 1-nonene units, 1-decene units, 1-undecene units, 1-dodecene units, 1-tridecene units, 1-tetradecene units, 1-pentadecene units, 1-hexadecene units, 1-heptadecene units, 1-octadecene units, 1-nonadecene units, 1-eicosene units, 3-methyl-1-butene units, 3-methyl-1-pentene units, 4-methyl-1-pentene units, 2-ethyl-1-hexene units, and 2,2,4-trimethyl-1-pentene units. The crystalline polypropylene (B1) may contain only one of these other structural units, or two or more of them.

[0072] The melt flow rate (MFR) of the crystalline polypropylene (B1) measured in accordance with JIS K7210 at a measurement temperature of 230°C and a measurement load of 21.2 N is preferably 0.5 to 50 g / 10 min. By setting the MFR of the crystalline polypropylene (B1) within the above range, the moldability tends to be excellent.

[0073] The amorphous polypropylene (B2) has an ethylene unit content of 7% by mass or more and 50% by mass or less relative to the total monomer units constituting the amorphous polypropylene (B2). The upper limit of the ethylene unit content is preferably 20% by mass or less, more preferably 15% by mass or less. The lower limit of the ethylene unit content is preferably 8% by mass or more, more preferably 10% by mass or more.

[0074] The propylene unit content of the amorphous polypropylene (B2) is usually 50% by mass or more and 93% by mass or less, based on the total monomer units constituting the amorphous polypropylene (B2). The upper limit of the propylene unit content of the amorphous polypropylene (B2) is preferably 92% by mass or less, more preferably 90% by mass or less. The lower limit of the propylene unit content of the amorphous polypropylene (B2) is preferably 80% by mass or more, more preferably 85% by mass or more. When the propylene unit content of the amorphous polypropylene (B2) is in the above range, it is preferred because the melting peak temperature described below is likely to fall within that range.

[0075] The amorphous polypropylene (B2) preferably has a melting peak temperature of 45°C or higher and 100°C or lower. When the melting peak temperature of the amorphous polypropylene (B2) is equal to or lower than the above upper limit, it is easy to impart fusion bonding to the members to be joined. From this viewpoint, the melting peak temperature of the amorphous polypropylene (B2) is more preferably 90°C or lower. From the viewpoint of heat resistance, the lower limit of the melting peak temperature of the amorphous polypropylene (B2) is preferably 45°C or higher, more preferably 55°C or higher.

[0076] The amorphous propylene-ethylene copolymer of the amorphous polypropylene (B2) may contain structural units other than ethylene and propylene units, for example, α-olefin units other than propylene. In this case, examples of the other α-olefin units 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. The amorphous polypropylene (B2) may contain only one type of these other structural units, or may contain two or more types.

[0077] The melt flow rate (MFR) of the amorphous polypropylene (B2) measured in accordance with JIS K7210 at a measurement temperature of 230°C and a measurement load of 21.2 N is preferably 1 to 10 g / 10 min. By setting the MFR of the amorphous polypropylene (B2) within the above range, it becomes easier to impart a strong shear force when melt-kneading the materials of the thermoplastic elastomer composition, and the material dispersibility tends to be excellent.

[0078] The crystalline polypropylene (B1) and amorphous polypropylene (B2) preferably have a crystalline polypropylene (B1) content of 70% to 90% by mass and an amorphous polypropylene (B2) content of 10% to 30% by mass, based on a total of 100% by mass of the crystalline polypropylene (B1) and amorphous polypropylene (B2). From the viewpoint of ensuring heat resistance while maintaining weldability and weld durability, it is more preferable that the crystalline polypropylene (B1) content be 75% to 85% by mass and the amorphous polypropylene (B2) content be 15% to 25% by mass, based on a total of 100% by mass of the crystalline polypropylene (B1) and amorphous polypropylene (B2).

[0079] The crystalline polypropylene (B1) and the amorphous polypropylene (B2) can be produced by a known polymerization method using a known olefin polymerization catalyst. For example, a polymerization method using a Ziegler-Natta catalyst can be used. Examples of the polymerization method include slurry polymerization, solution polymerization, bulk polymerization, and gas phase polymerization, and two or more of these methods can be used in combination.

[0080] The crystalline polypropylene (B1) and the amorphous polypropylene (B2) are also commercially available.

[0081] Commercially available products corresponding to crystalline polypropylene (B1) include "Prim Polypro (registered trademark)" manufactured by Prime Polymer Co., Ltd., "Sumitomo Noblen (registered trademark)" manufactured by Sumitomo Chemical Co., Ltd., "Polypropylene Block Copolymer" manufactured by SunAllomer Corporation, "Novatec (registered trademark) PP" manufactured by Japan Polypropylene Corporation, "Moplen (registered trademark)" manufactured by LyondellBasell, "ExxonMobil PP" manufactured by ExxonMobil, "Formolene (registered trademark)" manufactured by Formosa Plastics, "Borealis PP" manufactured by Borealis, "SEETEC PP" manufactured by LG Chemical, "ASI POLYPROPYLENE" manufactured by A. Schulman, "INEOS PP" manufactured by INEOS Olefins & Polymers, "Braskem PP" manufactured by Braskem, "Samsung Total" manufactured by SAMSUNG TOTAL PETROCHEMICALS, "Sabic (registered trademark) PP" manufactured by Sabic, and "TOTAL Examples include "TOTAL PETROCHEMICALS Polypropylene" manufactured by PETROCHEMICALS Co., Ltd. and "YUPLENE (registered trademark)" manufactured by SK Co., Ltd. An appropriate one can be selected from these and used.

[0082] Commercially available products corresponding to amorphous polypropylene (B2) include, for example, Prime TPO (registered trademark) manufactured by Prime Polymer, VERSIFY (registered trademark) manufactured by Dow Chemical, and Vistamaxx (registered trademark) manufactured by ExxonMobil Chemical. Examples of propylene-ethylene-1-butene copolymers include TAFMER (registered trademark) XM manufactured by Mitsui Chemicals. Any of these may be appropriately selected and used.

[0083] The crystalline polypropylene (B1) and the amorphous polypropylene (B2) contained in the propylene-based resin (B) may be used in combination of two or more types each having different compositions and physical properties.

[0084] The thermoplastic elastomer composition of the present invention preferably contains 40 parts by mass or more and 120 parts by mass or less of the propylene-based resin (B) (when components (B1) and (B2) are used as the propylene-based resin (B), the total of components (B1) and (B2)) per 100 parts by mass of the styrene-based elastomer (A). The lower limit of the content of the propylene-based resin (B) in the thermoplastic elastomer composition of the present invention is preferably 40 parts by mass or more, more preferably 50 parts by mass or more, and even more preferably 60 parts by mass or more, per 100 parts by mass of the styrene-based elastomer (A), from the viewpoint of moldability. The upper limit of the content of the propylene-based resin (B) in the thermoplastic elastomer composition of the present invention is preferably 120 parts by mass or less, more preferably 110 parts by mass or less, and even more preferably 100 parts by mass or less, per 100 parts by mass of the styrene-based elastomer (A), from the viewpoint of obtaining sufficient flexibility and hardness for a molded product.

[0085] In the thermoplastic elastomer composition of the present invention, the mass ratio of the styrene elastomer (A) to the propylene resin (B) (when components (B1) and (B2) are used as the propylene resin (B), the total mass of components (B1) and (B2)) is preferably 1.00 or more and 1.30 or less, and more preferably 1.10 or more and 1.27 or less. By setting the mass ratio of the styrene elastomer (A) to the propylene resin (B) within the above range, a good sea-island structure is formed in which the styrene elastomer (A) exists as an island phase in the sea phase of the propylene resin (B), and this tends to make it easier to achieve high levels of both fusion bonding property and compression set.

[0086] [Silicone-based lubricant (C)] Examples of the silicone-based lubricant (C) include silicone oil, silicone masterbatch, and liquid siloxane wax. The silicone-based lubricant (C) is used in an amount of preferably 0.5 to 50 parts by mass, more preferably 1 to 25 parts by mass, even more preferably 1.4 to 13.9 parts by mass, and particularly preferably 2.8 to 8.3 parts by mass, per 100 parts by mass of the styrene-based elastomer component (A). When the content of the silicone-based lubricant (C) is within the above range, deterioration in fusion properties can be suppressed and excellent sliding properties can be obtained.

[0087] The kinematic viscosity (25°C) of the silicone-based lubricant (C) is preferably 1 cSt or more, more preferably 5 cSt or more, and even more preferably 10 cSt or more, with no particular upper limit. Within the above range, the higher the kinematic viscosity, the more immediate the improvement in sliding properties, and the lower the viscosity, the more delayed the improvement in sliding properties. Here, the kinematic viscosity is the kinematic viscosity at 25°C measured using an Ubbelohde viscometer in accordance with ASTM D445-46T (or JIS Z8803).

[0088] As the silicone-based lubricant (C), commercially available products can also be used, specifically, "KF96-10CS", "KF96-100CS", "KF96-1000CS", and "KF96-5000CS" manufactured by Shin-Etsu Chemical Co., Ltd.

[0089] The silicone lubricant (C) may be used alone or as a mixture of two or more kinds in any combination and ratio.

[0090] [Hydrocarbon-based rubber softener (D)] From the viewpoint of improving moldability, the thermoplastic elastomer composition of the present invention preferably contains a hydrocarbon-based rubber softener (D) (hereinafter, sometimes referred to as "component (D)").

[0091] The lower limit of the content of the hydrocarbon-based rubber softener (D) in the thermoplastic elastomer composition of the present invention is usually 70 parts by mass or more, preferably 75 parts by mass or more, and more preferably 80 parts by mass or more, per 100 parts by mass of the styrene-based elastomer (A), from the viewpoint of moldability. The upper limit of the content of the hydrocarbon-based rubber softener (D) in the thermoplastic elastomer composition of the present invention is usually 130 parts by mass or less, preferably 125 parts by mass or less, and more preferably 120 parts by mass or less, per 100 parts by mass of the styrene-based elastomer (A), from the viewpoint of flexibility.

[0092] Examples of hydrocarbon-based rubber softeners (D) 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, with those in which 50% or more of the total carbon atoms are paraffinic hydrocarbons being called paraffinic oils, those in which 30 to 45% of the total carbon atoms are naphthenic hydrocarbons being called naphthenic oils, and those in which 35% or more of the total carbon atoms are aromatic hydrocarbons being called aromatic oils. Of these, paraffinic oils are preferred.

[0093] The kinematic viscosity of the hydrocarbon-based rubber softener (D) 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 hydrocarbon-based rubber softener is preferably 200°C or more, more preferably 250°C or more.

[0094] The hydrocarbon-based rubber softener (D) is commercially available. Examples of such commercially available products include 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. Appropriate products can be selected and used from these.

[0095] The hydrocarbon-based rubber softener (D) may be used alone or as a mixture of two or more kinds in any combination and ratio.

[0096] [Other ingredients] In the production of the thermoplastic elastomer composition of the present invention, other components may be used as raw materials as needed in addition to the above-described components (A) to (D), provided that the effects of the present invention are not impaired. Hereinafter, "component (B)" includes components (B1) and (B2).

[0097] Examples of other components include crosslinking agents, resins such as thermoplastic resins and elastomers other than component (A) and component (B), antioxidants, fillers, heat stabilizers, light stabilizers, ultraviolet absorbers, neutralizing agents, lubricants other than component (C), antifogging agents, antiblocking agents, slip agents, dispersants, colorants, flame retardants, antistatic agents, conductivity imparting agents, metal deactivators, molecular weight modifiers, antibacterial agents, antifungal agents, antibacterial agents, antiviral agents, and various additives such as fluorescent brighteners. Any of these may be used alone or in combination.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] Examples of crosslinking aids other than organic peroxides and 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.

[0102] When a crosslinking agent is used, the amount used is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more, per 100 parts by mass of the styrene-based elastomer (A), from the viewpoint of sufficiently progressing the crosslinking reaction. The amount used is preferably 10.0 parts by mass or less, more preferably 9.0 parts by mass or less, and even more preferably 8.0 parts by mass or less, per 100 parts by mass of the styrene-based elastomer (A), from the viewpoint of controlling the crosslinking reaction.

[0103] Examples of thermoplastic resins other than component (A) and component (B) 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 component (B)). Examples of elastomers other than component (A) and component (B) include polyester elastomers and polybutadiene. When the thermoplastic elastomer composition of a preferred embodiment of the present invention contains a resin other than components (A), (B1), and (B2), in order to fully obtain the effects of containing components (A) to (C), the content of the other resin is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less, per 100 parts by mass of the total of components (A) to (C).

[0104] Examples of the antioxidant (E) (hereinafter sometimes referred to as "component (E)") include phenol-based antioxidants, phosphite-based antioxidants, and thioether-based antioxidants. When the antioxidant (E) is used, the antioxidant (E) 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 styrene-based elastomer (A). When the content of the antioxidant (E) is within the above range, good thermal stability can be obtained.

[0105] Examples of fillers include glass fibers, hollow glass spheres, carbon fibers, talc, calcium carbonate, mica, potassium titanate fibers, silica, metal soap, titanium dioxide, and carbon black. When a filler is used, the filler is usually used in an amount of 0.3 to 100 parts by mass per 100 parts by mass of the styrene-based elastomer (A).

[0106] [Method of producing thermoplastic elastomer composition] The thermoplastic elastomer composition of the present invention is preferably obtained by melt-kneading a composition containing predetermined amounts of a styrene-based elastomer (A), a propylene-based resin (B) (component (B1) and component (B2) when component (B1) and component (B2) are used as the propylene-based resin (B)), a silicone-based lubricant (C), a hydrocarbon-based rubber softener (D), and other components.

[0107] In the present invention, examples of the mixing and kneading device used for melt-kneading include a non-open Banbury mixer, a mixing roll, a kneader, and a twin-screw extruder. Among these, a twin-screw extruder is preferably used. A preferred embodiment of the production method using a 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 perform melt-kneading.

[0108] The temperature at which the melt-kneading is carried out is usually 80 to 300°C, and preferably 100 to 250°C.

[0109] When the thermoplastic elastomer composition of the present invention is produced by melt-kneading 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)

[0110] 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.

[0111] [Physical properties of thermoplastic elastomer composition] The thermoplastic elastomer composition of the present invention is preferably a thermoplastic elastomer composition having a sea-island structure in which the styrene-based elastomer (A) exists as an island phase in the sea phase of the propylene-based resin (B), and the tear elongation measured by the above-mentioned tear elongation measuring method of the present invention is usually 230% or more. This tear elongation of 230% or more results in excellent fusion properties and fusion durability.

[0112] From the viewpoint of fusion durability, the tear elongation of the thermoplastic elastomer composition of the present invention is preferably 250% or more. There is no particular upper limit to this tear elongation, but it is usually 400% or less.

[0113] The thermoplastic elastomer composition of the present invention preferably has a tear strength of 40 N / mm or more, more preferably 50 N / mm or more, as measured by the tear elongation measuring method of the present invention. A tear strength of 30 N / mm or more is considered to be within the practical range for use as a sealing material for window frames of automobiles, etc. There is no particular upper limit to this tear strength, but it is usually 60 N / mm or less.

[0114] The thermoplastic elastomer composition of the present invention preferably has a compression set of 55% or less, measured under conditions of 70°C, 22 hours, and 25% compression in accordance with JIS K 6262. When the thermoplastic elastomer composition of the present invention has a compression set of 55% or less at 70°C, sufficient durability against compression can be obtained even in applications where the composition is used in a manner that involves repeated compression caused by opening and closing window frames, door frames, etc., such as sealing materials for automobiles and building materials.

[0115] From the viewpoint of moldability, the thermoplastic elastomer composition of the present invention preferably has a melt flow rate (MFR) of 0.5 g / 10 min or more, more preferably 0.7 g / 10 min or more, and even more preferably 0.9 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. From the viewpoint of moldability, the melt flow rate (MFR) of the thermoplastic elastomer composition of the present invention is preferably 80 g / 10 min or less, more preferably 75 g / 10 min or less, and even more preferably 70 g / 10 min or less.

[0116] From the viewpoint of weight reduction, the thermoplastic elastomer composition of the present invention has a density of 0.95 g / cm as measured by a method conforming to ISO 1183, Method A (underwater displacement method). 3 Preferably, the density is equal to or less than 0.93 g / cm 3More preferably, 0.91 g / cm or less 3 The lower limit of density is generally 0.90 g / cm 3 That's all.

[0117] From the viewpoint of obtaining appropriate fitability to substrates when used as a joining member, the thermoplastic elastomer composition of the present invention preferably has a lower limit of 19.0 MPa or more, more preferably 20.0 MPa or more, in tensile stress at break measured by a procedure conforming to the measurement method of JIS K 6251. From the viewpoint of preventing detachment of the joining member from the substrate once fitted, the upper limit of the tensile stress at break is preferably 29.0 MPa or less, more preferably 28.0 MPa or less.

[0118] From a similar viewpoint, the thermoplastic elastomer composition of the present invention preferably has an elongation at break of 950% or more, more preferably 1000% or more, measured by a procedure conforming to the measuring method of JIS K 6251. The upper limit of the elongation at break is preferably 1300% or less, more preferably 1200% or less, from the viewpoint of preventing the joining members from detaching from the substrates once fitted together.

[0119] [Molded object / Application] The thermoplastic elastomer composition of the present invention can be molded into a molded article by various molding methods typically used for thermoplastic elastomer compositions, such as injection molding, extrusion molding, blow molding, and compression molding. Among these, injection molding is preferred as a molding method for the thermoplastic elastomer composition of the present invention. After these moldings, the composition can also be molded into a molded article by secondary processing such as lamination molding and thermoforming.

[0120] Molded articles made from the thermoplastic elastomer composition of the present invention can be used in 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.

[0121] The molded article made of the thermoplastic elastomer composition of the present invention is suitable for use as a sealing material for automobiles and a sealing material for building materials, among the above-mentioned, and is particularly suitable as a sealing material for automobiles, particularly as a glass run channel for automobiles.

[0122] [Joining materials and composite moldings] A joining member can be produced by melt-kneading the thermoplastic elastomer composition of the present invention and then preferably injection-molding the kneaded product.

[0123] The composite molded article of the present invention is a composite molded article comprising a joining member made of a first thermoplastic elastomer composition, which is the thermoplastic elastomer composition of the present invention, and a joined member made of a second thermoplastic elastomer composition, and is usually produced by melt-kneading the thermoplastic elastomer composition of the present invention and injection-molding the kneaded mixture onto a joined member, such as an extrusion-molded member, made of the second thermoplastic elastomer composition.

[0124] The composite molded article of the present invention is a composite molded article comprising a joining member made of a first thermoplastic elastomer composition and a joined member made of a second thermoplastic elastomer composition, wherein the first thermoplastic elastomer composition is a thermoplastic elastomer composition having a sea-island structure in which a styrene-based elastomer (A) exists as an island phase in a sea phase of a propylene-based resin (B), and the second thermoplastic elastomer composition comprises a thermoplastic elastomer containing a propylene-based resin, and wherein the composite molded article has a tear elongation of 230% or more when measured by the above-mentioned tear elongation measuring method of the present invention using the first thermoplastic elastomer composition as a sample thermoplastic elastomer composition and the second thermoplastic elastomer composition as a thermoplastic elastomer composition for an insert material.

[0125] In this composite molded product, the propylene-based resin (B) is composed of crystalline polypropylene (B1) and amorphous polypropylene (B2), and when the total of the crystalline polypropylene (B1) and amorphous polypropylene (B2) is taken as 100% by mass, the content of the crystalline polypropylene (B1) is preferably 70% by mass to 90% by mass and the content of the amorphous polypropylene (B2) is 10% by mass to 30% by mass, from the viewpoint of ensuring heat resistance while maintaining weldability and weld durability. From these viewpoints, it is more preferable that the content of the crystalline polypropylene (B1) is 75% by mass to 85% by mass and the content of the amorphous polypropylene (B2) is 15% by mass to 25% by mass, based on a total of 100% by mass of the crystalline polypropylene (B1) and amorphous polypropylene (B2).

[0126] The bonded members constituting the composite molded article of the present invention are preferably made of olefinic rubber. Specific examples of olefinic rubber include olefinic thermoplastic elastomers and sulfur-vulcanized rubbers. From the viewpoint of obtaining good fusion properties, it is preferable to use a thermoplastic elastomer composition containing a propylene-based resin as a sea phase.

[0127] The thermoplastic elastomer composition containing a propylene-based resin as a sea phase, which constitutes the members to be joined, preferably has a Duro A hardness of 75 to 85 and a melting point of 133 to 143°C.

[0128] As the thermoplastic elastomer to be used for the joined member, an olefin-based thermoplastic elastomer or a styrene thermoplastic elastomer is preferred, and among these, an olefin-based dynamically crosslinked thermoplastic elastomer is preferred, since they have excellent fusion properties with the thermoplastic elastomer composition of the present invention and also have excellent mechanical strength and compression set (sag resistance) as the frame part of an automotive glass run channel.

[0129] Olefin-based dynamically crosslinked thermoplastic elastomer compositions containing a propylene-based resin as a sea phase are commercially available. Examples of such commercially available products include "TREXPRENE (registered trademark)" manufactured by Mitsubishi Chemical Corporation. Appropriate products can be selected and used from these.

[0130] The composite molded article of the present invention is particularly suitable as a composite molded article for a glass run channel for an automobile.

[0131] 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 thermoplastic elastomer composition of the present invention.

[0132] 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 thermoplastic elastomer composition of the present invention into the die to form joining members 2 at the corner portions, and fusing and integrating them with the end faces of the joined members 1A and 1B. [Example]

[0133] The present invention will be described in more detail below using examples. 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.

[0134] 〔raw materials〕 The raw materials used in the following examples and comparative examples are as follows.

[0135] [Styrene-based elastomer (A)] <a-1> Styrene-butadiene-styrene hydrogenated block copolymer (having the structure of formula (I) above; styrene (block P) content: 32% by mass; weight-average molecular weight: 260,000) / "TAIPOL (registered trademark)-6151" manufactured by Taiwan Synthetic Rubber Co., Ltd. (TSRC)

[0136] [Propylene-based resin (B)] <Crystalline Polypropylene (B1)> <b1-1> Propylene-ethylene copolymer (MFR (JIS K7210): 1.3 g / 10 min (230°C, 21.2 N), melting peak temperature: 149°C, propylene unit content: 97% by mass, ethylene unit content: 3% by mass) / "Novatec (registered trademark) PP EG7F" manufactured by Japan Polypropylene Corporation

[0137] <Amorphous Polypropylene (B2)> <b2-1> Propylene-ethylene copolymer (MFR (JIS K7210): 8 g / 10 min (230°C, 21.2 N), melting peak temperature: 75°C, propylene unit content: 91% by mass, ethylene unit content: 9% by mass) / ExxonMobil Chemical Corporation "Vistamaxx® 3980FL" <b2-2> Propylene-ethylene copolymer (MFR (JIS K7210): 2 g / 10 min (230°C, 21.2 N), melting peak temperature: 65°C, propylene unit content: 89% by mass, ethylene unit content: 11% by mass) / ExxonMobil Chemical Corporation "Vistamaxx® 3020FL"

[0138] [Silicone-based lubricant (C)] <c-1> Silicone oil: Shin-Etsu Chemical Co., Ltd. "KF96-1000CS"

[0139] [Hydrocarbon-based rubber softener (D)] <d-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"

[0140] [Antioxidant (E)] <e-1> Phenolic antioxidant: BASF Japan "Irganox (registered trademark) 1010"

[0141] [Evaluation method] The thermoplastic elastomer compositions in the following examples and comparative examples were evaluated as follows.

[0142] For the measurements of (1) to (5) below, each 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 the conditions of an injection pressure of 50 MPa, a cylinder temperature of 220°C, and a mold temperature of 40°C.

[0143] (1) Duro A hardness: In accordance with JIS K6253 (JIS-A), the value was measured 15 seconds after pressing a needle against the test piece. The Duro A hardness is preferably in the range of 35 to 95, particularly 40 to 98, for use as an automobile sealing material.

[0144] (2) Tensile stress at break: As an index of the strength of a thermoplastic elastomer composition, the tensile stress at break was measured according to the procedure for measuring tensile stress at break specified in JIS K 6251. The larger the value of tensile stress at break, the more excellent the tensile properties required of the thermoplastic elastomer composition are evaluated to be.

[0145] (3) Elongation at break: As an index of the strength of a thermoplastic elastomer composition, the elongation at break was measured according to the procedure for measuring elongation at break specified in JIS K 6251. A thermoplastic elastomer composition having a larger elongation at break value is evaluated as having better tensile properties required for the composition.

[0146] (4) Compression set: Measured in accordance with JIS K6262 under conditions of 70°C, 22 hours, and 25% compression. The smaller the compression set value, the more excellent the durability.

[0147] (5) Coefficient of kinetic friction and coefficient of static friction The injection-molded sheet (120mm wide, 80mm long, 2mm thick) was cut into a 60cm x 45cm piece, and a 200g weight attached to a glass plate (110mm long x 110mm wide x 3mm thick) with double-sided tape was moved 6cm over the test piece to measure the dynamic and static friction coefficients. Three measurements were taken, and the average values ​​were calculated. The smaller the values ​​of the dynamic friction coefficient and static friction coefficient, the more excellent the sliding properties required for a thermoplastic elastomer composition are evaluated to be.

[0148] (6) Weld strength and elongation with a thermoplastic elastomer composition containing a propylene-based resin as a sea phase A 2 mm thick injection-molded sheet of a thermoplastic elastomer composition containing a propylene-based resin as a sea phase ("TREXPRENE® 3855N," manufactured by Mitsubishi Chemical Corporation, a dynamically crosslinked thermoplastic elastomer) was cut into a 10 cm x 5 cm piece and loaded into the mold of a 110-ton injection molding machine. Each thermoplastic elastomer composition was injected into the mold at a cylinder temperature of 210°C and a mold temperature of 40°C, and a composite molded article was obtained by insert molding. The composite molded article was punched out with a JIS No. 3 dumbbell and tensile strength was measured at 23°C at a tensile speed of 200 mm / min. The larger the values ​​of fusion strength and fusion elongation, the better the fusion properties required for a joining member are evaluated to be.

[0149] (7) Tear strength and tear elongation with a thermoplastic elastomer composition containing a propylene-based resin as a sea phase A 2 mm-thick injection-molded sheet of a thermoplastic elastomer composition containing a propylene-based resin as a sea phase ("TREXPRENE® 3855N," manufactured by Mitsubishi Chemical Corporation, a dynamically crosslinked thermoplastic elastomer) was cut into a 10 cm x 5 cm piece and loaded into the mold of a 110-ton injection molding machine. Each thermoplastic elastomer composition was injected into the mold at a cylinder temperature of 260°C and a mold temperature of 40°C, and a composite molded article was obtained by insert molding. The composite molded article was punched out using a JIS K6252 no-notch angle dumbbell. As shown in Figure 2, benchmark lines 10a and 10b were drawn 10 mm from the fusion interface 10C, for a total distance of 20 mm between the benchmark lines. The tear strength and tear elongation were then measured at 23°C and a tensile speed of 200 mm / min. The tear elongation was evaluated according to the following criteria. ◎: Tear elongation 250% or more ○: Tear elongation 230% or more and less than 250% ×: Tear elongation less than 230% This evaluation is an evaluation of fusion durability using an injection-molded sheet. From the results of this evaluation, the fusion durability of a composite molded product such as that shown in Figure 1 can be compared with the fusion strength and fusion elongation (6) and evaluated with good reproducibility.

[0150] [Examples / Comparative Examples] Example 1 A mixture of 100 parts by mass of (A-1), 69 parts by mass of (B1-1), 14 parts by mass of (B2-1), 5.6 parts by mass of (C-1), 94 parts by mass of (D-1), and 0.28 parts by mass of (E-1) was blended in a Henschel mixer for 1 minute to obtain a mixture. This mixture was fed into the feed section of a co-rotating twin-screw extruder (manufactured by The Japan Steel Works, Ltd., "TEX30α", L / D=46, number of cylinder blocks: 13) at a total rate of 15 kg / h, heated to a temperature range of 110 to 220°C, melt-kneaded, and pelletized to produce a thermoplastic elastomer composition.

[0151] It was confirmed by transmission electron microscopy that the resulting thermoplastic elastomer composition had a sea-island structure with component (B) as the sea phase and component (A) as the island phase.

[0152] The melt flow rate (MFR) of the obtained thermoplastic elastomer composition was measured at a measurement temperature of 230°C and a measurement load of 21.2N according to the method of JIS K7210. The density of the obtained thermoplastic elastomer composition was measured in accordance with ISO1183 Method A (water displacement method). The thermoplastic elastomer composition thus obtained was evaluated according to the above-mentioned items (1) to (7). The evaluation results are shown in Table 1.

[0153] <Examples 2 to 5 and Comparative Example 1> Pellets of thermoplastic elastomer compositions were obtained in the same manner as in Example 1, except that the blending composition was changed as shown in Table 1. The obtained thermoplastic elastomer compositions were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0154] In Table 1, "content of (B2)" refers to the content of amorphous polypropylene (B2) in a total of 100% by mass of crystalline polypropylene (B1) and amorphous polypropylene (B2).

[0155] [Table 1]

[0156] <Evaluation results> As shown in Table 1, Examples 1 to 5 are excellent in sliding properties, fusion properties, and fusion durability.

[0157] Comparative Example 1 is an example in which no amorphous polypropylene (B2) was used, and although the fusion strength and fusion elongation were not significantly different from those of the Examples, the tear elongation was small and the fusion durability was poor.

[0158] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention. This application is based on Japanese Patent Application No. 2020-158729 filed on September 23, 2020, the entire contents of which are incorporated by reference. [Industrial Applicability]

[0159] The 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 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, particularly as an automotive glass run channel. [Explanation of symbols]

[0160] 1A,1B Parts to be joined 2. Joint materials 3 Composite molded body 10 JIS K6252 Uncut angle dumbbell test piece

Claims

1. A thermoplastic elastomer composition comprising the following component (A), the following component (B) consisting of the following component (B1) and the following component (B2), and component (C), A thermoplastic elastomer composition having a sea-island structure in which component (A): a styrene-based elastomer is present as an island phase in a sea phase of component (B): a propylene-based resin, The component (B2) is a thermoplastic elastomer composition having a melt flow rate (MFR) of 1 to 10 g / 10 min, measured at a temperature of 230° C. and a load of 21.2 N. Component (A): Styrene-based elastomer Component (B1): Crystalline polypropylene Component (B2): amorphous polypropylene Component (B): Propylene-based resin Component (C): Silicone-based lubricant

2. The thermoplastic elastomer composition according to claim 1, having a tear elongation of 230% or more as measured by the following method. <Method for measuring tear elongation> An injection molding die is loaded with an injection-molded sheet of a thermoplastic elastomer composition (Duro A hardness: 75 to 85, melting point: 133 to 143°C) containing a propylene-based resin as a sea phase as an insert material, and the thermoplastic elastomer composition of claim 1 is injection-molded at 260°C to obtain a composite molded product. A JIS K6252 unnotched angle dumbbell test piece is punched out from the molded product, and the tear elongation from a distance of 20 mm between the benchmark lines is measured at a test temperature of 23°C and a test speed of 200 mm / min.

3. 3. The thermoplastic elastomer composition according to claim 1, wherein the content of the component (B2) is 10% by mass or more and 30% by mass or less, when the total of the component (B1) and the component (B2) is 100% by mass.

4. The thermoplastic elastomer composition according to any one of claims 1 to 3, wherein a mass ratio of the component (A) to the total mass of the component (B1) and the component (B2) is 1.00 or more and 1.30 or less.

5. The thermoplastic elastomer composition according to any one of claims 1 to 4, wherein the compression set measured in accordance with JIS K6262 under conditions of 70°C, 22 hours, and 25% compression is 55% or less.

6. The thermoplastic elastomer composition according to any one of claims 1 to 5, which has an elongation at break of 950% or more as measured with reference to JIS K6251.

7. A joining member made of the thermoplastic elastomer composition according to any one of claims 1 to 6.

8. A corner member for an automobile, comprising the joining member according to claim 7.

9. A composite molded article comprising a joining member made of a first thermoplastic elastomer composition and a joined member made of a second thermoplastic elastomer composition, wherein the first thermoplastic elastomer composition is the thermoplastic elastomer composition according to any one of claims 1 to 6.

10. A glass run channel for an automobile, comprising the composite molded article according to claim 9.

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