Vehicle seat pad and automotive interior member

Abstract

Provided are: a vehicle seat pad that has excellent recyclability and with which ride comfort can be ensured; and an automotive interior member.　A vehicle seat pad (10A, 10B, 10C) and an automotive interior member (201) are composed of a non-crosslinked thermoplastic resin foam.

Description

Vehicle seat pads and vehicle interior components

[0001] The present disclosure relates to a vehicle seat pad and a vehicle interior member.

[0002] Patent Document 1 discloses a vehicle seat pad made of a flexible polyurethane foam with a predetermined hardness and impact resilience. It is stated that this flexible polyurethane foam can be made thinner while maintaining good vibration characteristics that affect ride comfort and good bottoming out feeling that affects seating comfort.

[0003] Japanese Patent Application Laid-Open No. 2005-206780

[0004] In recent years, from the viewpoint of reducing environmental impact, recyclability has also been demanded for vehicle seat pads. However, flexible polyurethane foams have the problem of poor recyclability. Vehicle seat pads are also products that require a high level of ride comfort. Recyclability is also demanded for vehicle interior components. Vehicle interior components are also products that require desired physical properties for each product.

[0005] The present disclosure aims to provide a vehicle seat pad that is highly recyclable and ensures ride comfort. The present disclosure also aims to provide a vehicle interior member that is highly recyclable and ensures desired physical properties. The present disclosure can be realized in the following forms.

[0006] A vehicle seat pad made of a non-crosslinked thermoplastic resin foam. A vehicle interior component made of a non-crosslinked thermoplastic resin foam.

[0007] According to the present disclosure, a vehicle seat pad that is highly recyclable and ensures ride comfort can be provided. Also, according to the present disclosure, a vehicle interior member that is highly recyclable and ensures desired physical properties can be provided.

[0008] Fig. 1 is a perspective view of a vehicle seat using the seat pads of Embodiments 1 and 2. Fig. 2 is a partial cross-sectional view of an interior member for a vehicle of Embodiment 3. Fig. 3 is a perspective view of a seat pad for a motorcycle of another embodiment.

[0009] Here, preferred examples of the present disclosure are described. [1] A vehicle seat pad made of a non-crosslinked thermoplastic resin foam. [2] A vehicle seat pad made of a thermoplastic resin foam, wherein a test piece of 100 mm x 100 mm x 10 mm is taken from the thermoplastic resin foam and the apparent density thereof is measured to be D1 kg / m or less. ３ The test piece is heat-pressed for 1 minute under a condition of 30 kPa at a temperature at which the uncrosslinked thermoplastic resin, which is a raw material of the thermoplastic resin foam, melts, and the apparent density of the test piece after heat pressing is D2 kg / m ３ [3] A vehicle seat pad, wherein the apparent density of the thermoplastic resin foam is 200 kg / m ３ [4] The vehicle seat pad according to any one of [1] to [3], wherein, when a pressing surface of a pressure tool including a circular pressing surface having a diameter of 50 mm is applied to a surface of the vehicle seat pad and the vehicle seat pad is compressed at a speed of 50 mm / min, the compressive stress of the thermoplastic resin foam at a depth of 3 mm from the surface is 100 N / 50 mm diameter or less. [5] The vehicle seat pad according to any one of [1] to [4], wherein the 25% compression hardness of the thermoplastic resin foam measured in accordance with JIS K6400-2:2012, Method D, is 700 N / 50 mm diameter or less. [6] The vehicle seat pad according to any one of [1] to [5], wherein the rebound resilience of the thermoplastic resin foam measured in accordance with JIS K 6400-3:2011 is 50% or more and 80% or less. [7] The vehicle seat pad according to any one of [1] to [6], wherein the thermoplastic resin foam is molded. [8] A vehicle interior member made of a non-crosslinked thermoplastic resin foam.

[0010] The present disclosure will be described in detail below. In this specification, the upper and lower limit values ​​of each numerical range can be combined in any way. In addition, in this specification, when a numerical range is described using "-", both the lower limit value and the upper limit value are included unless otherwise specified. For example, the description "10-20" includes both the lower limit value "10" and the upper limit value "20". In other words, "10-20" has the same meaning as "10 or more and 20 or less". In addition, in this specification, the upper and lower limit values ​​of each numerical range can be combined in any way.

[0011] <Embodiment 1> The seat pad 10 of embodiment 1 is made of a non-crosslinked thermoplastic resin foam. The seat pad 10 may be made entirely of a non-crosslinked thermoplastic resin foam, or may be made partially of a non-crosslinked thermoplastic resin foam.

[0012] 1. Specific Configuration of Seat Pad 10 FIG. 1 shows an example of a vehicle seat 1 in which the seat pad 10 of this embodiment is used. The vehicle seat 1 includes, for example, the seat pad 10, a frame (not shown) that supports the seat pad 10, and a trim cover (not shown) that covers the outer surface of the seat pad 10. Arrow FR, appropriately shown in FIG. 1 , indicates the forward direction of the vehicle seat 1 (the direction in which the seated occupant faces), and arrow RR indicates the rearward direction of the vehicle seat 1. Arrow RH indicates the rightward direction of the vehicle seat 1, and arrow LH indicates the leftward direction of the vehicle seat 1. Arrow UP indicates the upward direction of the vehicle seat 1, and arrow DW indicates the downward direction of the vehicle seat 1. Hereinafter, when the terms "front-rear," "up-down," and "left-right" are used in descriptions, these terms will refer to the front-rear, the up-down, and the left-right directions of the vehicle seat 1, unless otherwise specified.

[0013] The seat pad 10 may be a seat pad 10A constituting a seat cushion. The seat pad 10A has, for example, a main portion 11A supporting the buttocks or thighs of a seated occupant and side portions 13A, 13A located on the left and right sides of the main portion 11A. For example, in the seat pad 10A, the side portions 13A may be made of a non-crosslinked thermoplastic resin foam. In that case, the main portion 11A may be at least partially made of a non-crosslinked thermoplastic resin foam, or may be made of a cushioning material other than a non-crosslinked thermoplastic resin foam.

[0014] The seat pad 10 may be a seat pad 10B that constitutes a seat back. The seat pad 10B has, for example, a main portion 11B that supports the back or lumbar region of a seated occupant and side portions 13B, 13B located on the left and right sides of the main portion 11B. In the seat pad 10B, the side portions 13B may be made of a non-crosslinked thermoplastic resin foam. In that case, the main portion 11B may be at least partially made of a non-crosslinked thermoplastic resin foam, or may be made of a cushioning material other than a non-crosslinked thermoplastic resin foam.

[0015] The seat pad 10 may be a seat pad 10C that constitutes a headrest. The entire seat pad 10C, i.e., the portion that supports the head of a seated occupant, may be made of a non-crosslinked thermoplastic resin foam, for example.

[0016] In this specification, when there is no need to distinguish between the seat pads 10A, 10B, and 10C, they will be simply referred to as the seat pad 10. The description of the seat pad 10 may apply to only one of the seat pads 10A, 10B, and 10C, or to two or more of them.

[0017] The shape and size of the seat pad 10 can be set appropriately depending on the part of the vehicle seat 1. The thickness of the seat pad 10 is preferably 20 mm or more, and may be 25 mm or more, 30 mm or more, or 40 mm or more. There is no particular upper limit to the thickness of the seat pad 10, and it is usually 120 mm or less, and may be, for example, 100 mm or less, 80 mm or less, or 70 mm or less.

[0018] 2. Thermoplastic Resin Foam (1) Crosslinked Structure In a non-crosslinked thermoplastic resin foam, the thermoplastic resin in the thermoplastic resin foam does not have a crosslinked structure. The non-crosslinked thermoplastic resin foam can be obtained from a foam composition containing a non-crosslinked thermoplastic resin and a raw material gas. The foam composition may contain components other than the above-mentioned thermoplastic resin and the raw material gas. However, it is preferable that the foam composition does not contain a crosslinking agent. It is also preferable that the foam composition does not contain a chemical blowing agent. The above-mentioned thermoplastic resin may be of only one type, or may be of two or more types.

[0019] The gel fraction of the non-crosslinked thermoplastic resin foam, when extracted with acetone as the extraction solvent according to JIS K 6796:1998, is preferably 5% or less, more preferably 3% or less. The gel fraction of the non-crosslinked thermoplastic resin foam may be 0%. When the gel fraction is within the above range, the non-crosslinked thermoplastic resin foam has excellent recyclability as a non-crosslinked thermoplastic resin foam in which a crosslinked structure is not formed.

[0020] (2) Thermoplastic Resin The thermoplastic resin is, for example, one or more selected from the group consisting of thermoplastic polyurethane resin (TPU), ethylene-vinyl acetate copolymer (EVA), thermoplastic styrene-based elastomer, thermoplastic polyamide-based elastomer (TPAE), thermoplastic polyester-based elastomer (TPEE), thermoplastic olefin-based elastomer, fluororesin, and polyolefin-based resin. Thermoplastic polyurethane resin is sometimes referred to as thermoplastic polyurethane elastomer. A specific example of a thermoplastic styrene-based elastomer is styrene-ethylene-butylene-styrene copolymer (SEBS). A specific example of a thermoplastic polyamide-based elastomer (TPAE) is polyether block amide (PEBA, for example, PEBAX (registered trademark) manufactured by Arkema). Specific examples of fluororesins are polyvinylidene fluoride (PVDF), perfluoroalkoxyalkane (PFA), and ethylene-tetrafluoroethylene copolymer (ETFE). From the viewpoint of improving the sitting comfort, the thermoplastic resin is preferably a thermoplastic elastomer, more preferably a thermoplastic polyurethane resin and / or a thermoplastic polyester-based elastomer, and even more preferably a thermoplastic polyurethane resin.

[0021] Thermoplastic polyurethane resins are typically obtained from polyurethane resin compositions containing a polyisocyanate component and a polyol component. The polyol component preferably comprises a first polyol component having a molecular weight of 400 or more and 5,000 or less, and a second polyol component having a molecular weight of 60 or more and less than 400. When the polyol component contains a polymer, the number average molecular weight of the polymer is used. The number average molecular weight of the polymer can be measured by gel permeation chromatography (GPC).

[0022] The polyisocyanate component is preferably a diisocyanate compound. The polyisocyanate component is, for example, one or more compounds selected from the group consisting of tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, naphthalene diisocyanate, isophorone diisocyanate, and xylene diisocyanate. The polyisocyanate component may be one compound or two or more compounds.

[0023] The first polyol component is preferably one or more selected from the group consisting of polyester polyols, polyether polyols, lactone polyols, and polycarbonate polyols. The first polyol component may be one type only, or two or more types.

[0024] Polyester-based polyols are compounds obtained by condensation reactions between polyhydric alcohols such as ethylene glycol, propylene glycol, butanediol, butenediol, hexanediol, pentanediol, neopentyldiol, and pentanediol and aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, and maleic acid, or aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid. Polyether-based polyols are, for example, polyethylene ether glycol, polypropylene ether glycol, polytetramethylene ether glycol, and polyhexamethylene ether glycol. Lactone-based polyols are, for example, polycaprolactone glycol, polypropiolactone glycol, and polyvalerolactone glycol. Polycarbonate-based polyols are, for example, compounds obtained by dealcoholization reactions between polyhydric alcohols such as ethylene glycol, propylene glycol, butanediol, pentanediol, octanediol, and nonanediol and diethylene carbonate, dipropylene carbonate, and the like.

[0025] The second polyol component is preferably a compound (monomer) having two or more hydroxyl groups in the molecule and having a molecular weight of 60 or more and less than 400. The second polyol component may be of only one type, or may be of two or more types.

[0026] Examples of the second polyol component include ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butylene glycol (1,4-butanediol, 1,4-BD), 1,3-butylene glycol, 1,2-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,2,2-trimethylpentanediol, 3,3-dimethylolheptane, alkane (C7-11) diols, cyclohexanedimethanol (1,3- or 1,4-cyclohexanedimethanol and mixtures thereof), cyclohexanediol (1, dihydric alcohols such as 1,3- or 1,4-cyclohexanediol and mixtures thereof), 1,4-dihydroxy-2-butene, 2,6-dimethyl-1-octene-3,8-diol, diethylene glycol, triethylene glycol, dipropylene glycol, 1,2-benzenediol (also known as catechol), 1,3-benzenediol, 1,4-benzenediol, bisphenol A and hydrogenated products thereof; trihydric alcohols such as glycerin, trimethylolpropane, triisopropanolamine; and polyhydric alcohols such as tetrahydric alcohols such as tetramethylolmethane (pentaerythritol) and diglycerin.

[0027] The thermoplastic polyurethane resin is preferably a linear multi-block copolymer of a block obtained by the reaction of a first polyol component with a polyisocyanate component and a block formed of a second polyol component with an isocyanate. The block obtained by the reaction of the first polyol component with the polyisocyanate component constitutes a soft segment. The block obtained by the reaction of the first polyol component with the polyisocyanate component constitutes a hard segment.

[0028] From the viewpoint of recyclability, the thermoplastic polyurethane resin preferably has an NCO index (NCO groups / OH groups) of 85 to 120, more preferably 90 to 110, and even more preferably 95 to 105. When the NCO index is within the above range, the residual isocyanate groups in the thermoplastic polyurethane resin can be suitably reduced, and the formation of a crosslinked structure can be suppressed.

[0029] (3) Raw Material Gas Examples of supercritical fluids used as raw material gases include carbon dioxide and nitrogen (N ２ ), helium, argon, nitrous oxide, ethylene, ethane, tetrafluoroethylene, perfluoroethane, tetrafluoromethane, trifluoromethane, 1,1-difluoroethylene, trifluoroamide oxide, cis-difluorodiamine, trans-difluorodiamine, nitrogen difluoride chloride, phosphorus tritide, dinitrogen tetrafluoride, ozone, phosphine, nitrosyl fluoride, nitrogen trifluoride, deuterium chloride, xenon, sulfur hexafluoride, fluoromethane, pentafluoroethane, 1,1-difluoroethene, diborane, water, tetrafluorohydrazine, silane, silicon tetrafluoride, germanium tetrahydride, boron trifluoride, carbonyl fluoride, chlorotrifluoromethane, bromotrifluoromethane, vinyl fluoride, and the like. The supercritical fluid is preferably carbon dioxide, nitrogen, nitrous oxide, ethylene, ethane, tetrafluoroethylene, perfluoroethane, tetrafluoromethane, trifluoromethane, or 1,1-difluoroethylene, more preferably at least one selected from nitrogen gas and carbon dioxide gas, and even more preferably nitrogen gas. Nitrogen gas and carbon dioxide gas are suitable as supercritical fluids due to their high gas retention properties during the production of a non-crosslinked thermoplastic resin foam.

[0030] (4) Method for Producing Thermoplastic Resin Foam A method for producing a non-crosslinked thermoplastic resin foam is preferably a method for melting a thermoplastic resin, kneading the mixture with a supercritical fluid, and then injection-foaming the mixture (hereinafter also referred to as an injection foaming method). A method for producing a non-crosslinked thermoplastic resin foam is also preferably a method for impregnating a molten thermoplastic resin with a supercritical fluid (hereinafter also referred to as a batch foaming method).

[0031] The injection foaming method can be performed using, for example, an injection molding apparatus. This injection molding apparatus includes an injection device having a cylinder and a screw rotatably supported within the cylinder, and a mold device that molds the molten resin injected from the injection device. Specifically, the injection foaming method involves mixing a thermoplastic resin and a supercritical fluid with the screw of the injection device to form a resin mixture, and then injecting the resin mixture into the mold device to mold a thermoplastic resin foam.

[0032] The batch foaming method can be carried out using, for example, a reaction vessel capable of maintaining high temperature and high pressure, i.e., a so-called autoclave. Specifically, the batch foaming method involves impregnating a thermoplastic resin with a supercritical fluid in a reaction vessel, and generating bubbles by releasing the pressure and / or heating.

[0033] When a thermoplastic resin foam is obtained by the batch foaming method, the thermoplastic resin foam may be further subjected to thermocompression molding. Thermocompression molding is a method in which a primary foam obtained by the batch foaming method is heated for a predetermined time, compressed in a direction that reduces the thickness of the primary foam, and then cooled to obtain a secondary molded product. Compared to the primary foam, the secondary molded product obtained by thermocompression molding not only has a smaller thickness, but also has higher density and hardness, and is expected to have improved impact resilience. Furthermore, thermocompression molding can also adjust the external shape of the thermoplastic resin foam. Both the primary foam and the secondary foam can be used as a seat pad as is.

[0034] The method for producing a non-crosslinked thermoplastic resin foam may further include any step other than the steps described above. However, the method for producing a non-crosslinked thermoplastic resin foam does not include a step of crosslinking a thermoplastic resin. The step of crosslinking a thermoplastic resin includes, for example, a step of adding a crosslinking agent and heating to form a crosslinked structure, a step of irradiating with active energy rays to form a crosslinked structure, and a step of reacting reactive functional groups remaining in the thermoplastic resin to form a crosslinked structure.

[0035] A conventional method for producing a thermoplastic resin foam is known, which involves melting a thermoplastic resin, kneading a blowing agent, and then extruding the resulting foam (extrusion foaming). However, the non-crosslinked thermoplastic resin foam obtained by the extrusion foaming method has limited shape flexibility. For example, to achieve a thickness suitable for a vehicle seat pad, multiple extruded foams must be laminated. Another conventional method for producing a thermoplastic resin foam is known, which involves melting a thermoplastic resin, kneading a blowing agent, and then performing primary foaming to produce a foam strand. The foam strand is then cut to obtain foam beads, which are then melt-molded and secondary foamed in a mold (bead foaming). However, the non-crosslinked thermoplastic resin foam obtained by the bead foaming method is unsuitable for vehicle seat pads in terms of heat resistance and compression resistance. Furthermore, the bead foaming method results in fused joints between the foam beads, which makes the foam unsuitable for vehicle seat pads in terms of peeling at the fused joints and the texture of the fused joints.

[0036] That is, the seat pad 10 is preferably made of a non-crosslinked thermoplastic resin foam (excluding thermoplastic resin foams obtained by extrusion foaming and bead foaming). When such a non-crosslinked thermoplastic resin foam is observed in a cross section along the thickness direction, for example, no layered structure is observed. Furthermore, such a non-crosslinked thermoplastic resin foam does not include, for example, a thermoplastic resin foam that is an aggregate of bead-like particles.

[0037] The seat pad 10 is more preferably made of a non-crosslinked thermoplastic resin foam obtained by a method of melting a thermoplastic resin, kneading it with a supercritical fluid, and then injection-foaming it. It is also preferable that the seat pad 10 is made of a molded thermoplastic resin foam. Such a seat pad 10 is advantageous in that it can shorten the takt time required for production, the foaming composition used as a raw material can be easily customized, and there is a high degree of freedom in shape.

[0038] It is also preferable that the seat pad 10 be made of a non-crosslinked thermoplastic resin foam obtained by impregnating a thermoplastic resin with a supercritical fluid. It is also preferable that the seat pad 10 be made by thermocompression molding a thermoplastic resin foam. For example, the non-crosslinked thermoplastic resin foam may be obtained by thermocompression molding a primary foam obtained by impregnating a thermoplastic resin with a supercritical fluid. Such a seat pad 10 is advantageous in that it can be manufactured using, for example, a general-purpose reaction vessel or existing equipment for thermocompression molding.

[0039] 3. Physical Properties of Thermoplastic Resin Foam The physical properties of the uncrosslinked thermoplastic resin foam are not particularly limited as long as they do not impair the effects of the present disclosure.

[0040] The apparent density of the thermoplastic resin foam (based on JIS K7222:2005) is 30 kg / m ３ More than 200kg / m ３ Preferably less than 80 kg / m ３ More than 180kg / m ３ More preferably, 130 kg / m or less ３ More than 150kg / m ３ The following is even more preferred:

[0041] The compressive stress of the thermoplastic resin foam is preferably 100 N / 50 mm diameter or less, more preferably 90 N / 50 mm diameter or less, even more preferably 80 N / 50 mm diameter or less, still more preferably 80 N / 50 mm diameter or less, and particularly preferably 70 N / 50 mm diameter or less. The compressive stress is usually 10 N / 50 mm diameter or more, and may be 14 N / 50 mm diameter or more.

[0042] When the side portion 13A of the seat cushion is made of the thermoplastic resin foam, the compressive stress of the thermoplastic resin foam is preferably 120 N / 50 mm diameter or less, more preferably 100 N / 50 mm diameter or less, and even more preferably 80 N / 50 mm diameter or less. This compressive stress may be 14 N / 50 mm diameter or more. When the main portion 11A of the seat cushion is made of the thermoplastic resin foam, the compressive stress of the thermoplastic resin foam is preferably 100 N / 50 mm diameter or less, more preferably 85 N / 50 mm diameter or less, and even more preferably 70 N / 50 mm diameter or less. This compressive stress may be 14 N / 50 mm diameter or more. When the side portion 13B of the seat back is made of the thermoplastic resin foam, the compressive stress of the thermoplastic resin foam is preferably 120 N / 50 mm diameter or less, more preferably 100 N / 50 mm diameter or less, and even more preferably 80 N / 50 mm diameter or less. This compressive stress may be 14 N / 50 mm diameter or more. When the main portion 11B of the seat back is made of the above-mentioned thermoplastic resin foam, the compressive stress of the thermoplastic resin foam is preferably 100 N / 50 mm diameter or less, more preferably 85 N / 50 mm diameter or less, and even more preferably 70 N / 50 mm diameter or less. This compressive stress may be 14 N / 50 mm diameter or more. When the headrest is made of the above-mentioned thermoplastic resin foam, the compressive stress of the thermoplastic resin foam is preferably 120 N / 50 mm diameter or less, more preferably 100 N / 50 mm diameter or less, and even more preferably 80 N / 50 mm diameter or less. This compressive stress may be 14 N / 50 mm diameter or more.

[0043] The compressive stress (N / diameter 50 mm) of the thermoplastic resin foam is measured using a pressure probe. The pressure probe is cylindrical with a circular pressing surface (tip surface) of 50 mm diameter, and is placed perpendicular to the surface of the thermoplastic resin foam, which is the object to be measured, when measuring the compressive stress. At this time, the pressing surface of the pressure probe is placed against the surface of the thermoplastic resin foam. In this way, when the pressing surface is placed against the surface of the thermoplastic resin foam and the thermoplastic resin foam is compressed at a speed (compression speed) of 50 m / min, the load read at a depth of 3 mm from the surface is calculated using the pressure probe at a pressure surface of 50 mm diameter (= 19.6 cm ２ Furthermore, when the extrusion surface is convex, the load was measured when a circular pressurizer (diameter 50 mm) first touched the surface of the thermoplastic resin foam and compressed it 3 mm from the point where it first touched the surface. On the other hand, when the extrusion surface is concave, the load was measured when a circular pressurizer (diameter 50 mm) touched the surface of the thermoplastic resin foam at two or more points and compressed it 3 mm from the point where it first touched the surface. This load was measured as a compressive stress per 50 mm diameter pressing surface (= 19.6 cm). ２ ) was used as the compressive stress per

[0044] The compressive stress can be controlled by adjusting the type of thermoplastic resin and the expansion ratio of the thermoplastic resin foam. For example, when a thermoplastic urethane resin is used as the thermoplastic resin, the compressive stress can be suitably reduced compared to when a polypropylene resin is used. Furthermore, increasing the expansion ratio of the thermoplastic resin foam tends to reduce the compressive stress, while decreasing the expansion ratio of the thermoplastic resin foam tends to increase the compressive stress.

[0045] The 25% compression hardness of the thermoplastic resin foam measured in accordance with JIS K6400-2:2012 D method is preferably 700 N / diameter 50 mm or less, more preferably 600 N / diameter 50 mm or less, even more preferably 500 N / diameter 50 mm or less, still more preferably 300 N / diameter 50 mm or less, and particularly preferably 200 N / diameter 50 mm or less. The 25% compression hardness is usually 60 N / diameter 50 mm or more, and may be 70 N / diameter 50 mm or more.

[0046] When the side portion 13A of the seat cushion is made of the above-mentioned thermoplastic resin foam, the 25% compression hardness of the thermoplastic resin foam is preferably 500 N / 50 mm diameter or less, more preferably 400 N / 50 mm diameter or less, and even more preferably 300 N / 50 mm diameter or less. This 25% compression hardness may be 70 N / 50 mm diameter or more. When the main portion 11A of the seat cushion is made of the above-mentioned thermoplastic resin foam, the 25% compression hardness of the thermoplastic resin foam is preferably 400 N / 50 mm diameter or less, more preferably 300 N / 50 mm diameter or less, and even more preferably 200 N / 50 mm diameter or less. This 25% compression hardness may be 70 N / 50 mm diameter or more. When the side portion 13B of the seat back is made of the above-mentioned thermoplastic resin foam, the 25% compression hardness of the thermoplastic resin foam is preferably 500 N / 50 mm diameter or less, more preferably 400 N / 50 mm diameter or less, and even more preferably 300 N / 50 mm diameter or less. This 25% compression hardness may be 70 N / 50 mm diameter or more. When the main portion 11B of the seat back is made of the above-mentioned thermoplastic resin foam, the 25% compression hardness of the thermoplastic resin foam is preferably 400 N / 50 mm diameter or less, more preferably 300 N / 50 mm diameter or less, and even more preferably 200 N / 50 mm diameter or less. This 25% compression hardness may be 70 N / 50 mm diameter or more. When the headrest is made of the thermoplastic resin foam, the 25% compression hardness of the thermoplastic resin foam is preferably 500 N / 50 mm diameter or less, more preferably 300 N / 50 mm diameter or less, and even more preferably 200 N / 50 mm diameter or less. The 25% compression hardness may be 70 N / 50 mm diameter or more.

[0047] The 25% compression hardness can be measured in accordance with JIS K6400-2:2012 Method D as follows. The test specimen used for the measurement is the entire polyurethane foam including the skin. For example, in the examples described below, a rectangular thermoplastic resin foam including the skin is used as the test specimen. A pressure plate with a diameter of 50 mm is used for the measurement. During the measurement, the test specimen is placed on the support plate of the testing machine so that the center of the test specimen is at the center of the pressure plate.

[0048] The 25% compression hardness can be controlled by adjusting the type of thermoplastic resin and the expansion ratio of the thermoplastic resin foam. For example, when a thermoplastic urethane resin is used as the thermoplastic resin, the 25% compression hardness can be suitably reduced compared to when a polypropylene resin is used. Furthermore, when the expansion ratio of the thermoplastic resin foam is increased, the 25% compression hardness tends to decrease, and when the expansion ratio of the thermoplastic resin foam is decreased, the 25% compression hardness tends to increase.

[0049] The rebound resilience of the thermoplastic resin foam measured in accordance with JIS K 6400-3:2011 is preferably 50% or more and 80% or less, and more preferably 55% or more and 75% or less. The rebound resilience may be 70% or less, 65% or less, or 60% or less. The rebound resilience may be 35% or more, 40% or more, or 45% or more. The rebound resilience of the thermoplastic resin foam can be controlled by adjusting the type of thermoplastic resin. For example, if a raw material with high rebound resilience is used as the thermoplastic resin raw material, the rebound resilience of the thermoplastic resin foam tends to be high, and if a raw material with low rebound resilience is used, the rebound resilience of the thermoplastic resin foam tends to be low.

[0050] The tear strength of the thermoplastic resin foam measured in accordance with JIS K6400-5:2012 Method B is preferably 4 N / cm or more, more preferably 10 N / cm or more, even more preferably 15 N / cm or more, and may be 20 N / cm or more, 25 N / cm or more, 30 N / cm or more, or 35 N / cm or more. The upper limit of the tear strength is not particularly limited, and is, for example, 100 N / cm or less.

[0051] The compressive set of a thermoplastic resin foam measured in accordance with JIS K6400-4:2004 4.5 Method A (dry heat distortion) is, for example, 30% to 80%. The compressive set is calculated by compressing a test piece to 75% of its thickness and measuring the thickness of the test piece after 22 hours at 70°C. The wet heat compressive set of a thermoplastic resin foam measured in accordance with JIS K6400-4:2004 is, for example, 30% to 70%. The wet heat compressive set is calculated by compressing a test piece to 70% of its thickness and measuring the thickness of the test piece after 22 hours at 50°C and 95% relative humidity.

[0052] The 25% hardness change rate of the thermoplastic resin foam measured by the following method is preferably 25% or less, and may be 20% or less, 15% or less, or 12% or less. The lower limit of the 25% hardness change rate is usually 0%. [Method for measuring 25% hardness change rate] The 25% hardness change rate can be calculated according to JIS K6400-2:2012 by compressing a thermoplastic resin foam under conditions of a compression speed of 50 mm / min, pre-compression of 75%, and main compression of 25%, measuring the 25% hardness at the beginning of main compression and the 25% hardness after 24 hours of main compression, and then using the following formula: 25% hardness change rate = ((H1 - H2) / H1) × 100, where H1: 25% hardness (N) at the beginning of main compression, H2: 25% hardness (N) after 24 hours of main compression.

[0053] The 50% hardness change rate of a thermoplastic resin foam measured by the following method is preferably 25% or less, and may be 20% or less, 15% or less, or 12% or less. The lower limit of the 50% hardness change rate is usually 0%. [Method for measuring 50% hardness change rate] The 50% hardness change rate can be calculated according to JIS K6400-2:2012 by compressing the foam under conditions of a compression speed of 50 mm / min, pre-compression of 75%, and main compression of 50%, measuring the 50% hardness at the beginning of main compression and after 24 hours of main compression, and then calculating the 50% hardness using the following formula: 50% hardness change rate = ((H3 - H4) / H3) x 100, where H3 is the 50% hardness (N) at the beginning of main compression and H4 is the 50% hardness (N) after 24 hours of main compression.

[0054] The average cell diameter of a thermoplastic resin foam measured by the following method is preferably 40 μm or more, more preferably 50 μm or more, even more preferably 60 μm or more, and particularly preferably 70 μm or more. The upper limit of the average cell diameter is not particularly limited and may be, for example, 300 μm or less, 250 μm or less, 200 μm or less, or 150 μm or less. [Method for Measuring Average Cell Diameter] The average cell diameter of a thermoplastic resin foam can be determined by observing a cross section of the thermoplastic resin foam using a SEM (e.g., JSM-IT100, manufactured by JEOL Ltd.) and calculating the equivalent area circle diameter from the cell area. Specifically, the average particle diameter is determined as follows. Focus is placed on multiple cells that can be observed without missing parts in three observation fields (e.g., 200 μm × 200 μm). The diameter (equivalent area circle diameter) of an ideal circle (perfect circle) having an area equal to each cell's area (projected area) is calculated as the cell diameter of each cell. The average cell diameter is then calculated by arithmetically averaging the cell diameters of the individual cells. The cell diameters of the individual cells and the average cell diameter can be calculated using general image analysis software provided with the SEM.

[0055] 4. Effects of the Present Embodiment The effects of the present embodiment will be described. Non-crosslinked thermoplastic resin foam is a material that can be recycled as a thermoplastic resin without modification. However, it is difficult to ensure various physical properties such as hardness and impact resilience of non-crosslinked thermoplastic resin foam, and its application to the seat pad 10 has not been specifically considered. The present inventors have newly discovered a non-crosslinked thermoplastic resin foam that has excellent physical properties, and have developed the technology of the present disclosure in which this foam is applied to the seat pad 10. The seat pad 10 of the present embodiment is made of non-crosslinked thermoplastic resin foam, and therefore has excellent recyclability.

[0056] Furthermore, a conventional technique for applying thermoplastic resin to seat pads has been developed, in which thermoplastic resin filaments are wound and fused at their contact points to form a three-dimensional network structure. Such three-dimensional network structures are believed to be lightweight and have high resilience. However, three-dimensional network structures differ from ride comfort achieved by a fine cell structure and are not necessarily suitable for seat pads. In contrast, the seat pad 10 of this embodiment is made of a non-crosslinked thermoplastic resin foam, ensuring ride comfort through its fine cell structure.

[0057] <Embodiment 2> The seat pad of embodiment 2 is a vehicle seat pad made of a thermoplastic resin foam. The seat pad of embodiment 2 has an apparent density D1kg / m3 measured by taking a 100mm x 100mm x 10mm test piece from the thermoplastic resin foam. ３ The test piece was heat-pressed for 1 minute at a temperature at which the uncrosslinked thermoplastic resin, which is the raw material of the thermoplastic resin foam, melts under the condition of 30 kPa, and the apparent density of the test piece after heat pressing was D2 kg / m ３ When the ratio D2 / D1 is 3.5, the relationship D2 / D1 is satisfied. The seat pad may be made entirely of the above-mentioned thermoplastic resin foam, or may be made partially of the above-mentioned thermoplastic resin foam.

[0058] The seat pad of embodiment 2 differs from the seat pad 10 of embodiment 1 in that the thermoplastic resin foam may have a crosslinked structure and in that the requirements for D2 / D1 described above are satisfied. In the seat pad of embodiment 2, in the explanations of "(3) Raw material gas," "(4) Manufacturing method of thermoplastic resin foam," and "3. Physical properties of thermoplastic resin foam" in "1. Specific configuration of seat pad 10," "2. Thermoplastic resin foam" described in embodiment 1, the term "non-crosslinked thermoplastic resin foam" is read as "thermoplastic resin foam," and detailed explanations are omitted.

[0059] 1. Thermoplastic Resin Foam (1) Crosslinked Structure The thermoplastic resin foam may or may not have a crosslinked structure. A non-crosslinked thermoplastic resin foam is in a molten state at a temperature equal to or higher than the melting point of the thermoplastic resin and does not maintain its cell structure, so it can preferably satisfy the requirement for D2 / D1 described above. The description of the non-crosslinked thermoplastic resin foam in embodiment 1 applies as is, and a detailed description will be omitted.

[0060] Even if a thermoplastic resin foam has a crosslinked structure, it can satisfy the requirement for the above D2 / D1 when the crosslink density is low. The crosslink density can be evaluated, for example, by measuring the gel fraction described below.

[0061] Even if the thermoplastic resin foam has a crosslinked structure, the requirement for D2 / D1 can be satisfied if the thermoplastic resin is a dynamically crosslinked thermoplastic elastomer (TPV), which will be described later.

[0062] The thermoplastic resin foam of this embodiment can be obtained from a foam composition containing a thermoplastic resin and a raw material gas. The foam composition may contain components other than the above-mentioned thermoplastic resin and the raw material gas. The foam composition may not contain a crosslinking agent, or may contain a crosslinking agent. It is also preferable that the foam composition does not contain a chemical foaming agent. The above-mentioned thermoplastic resin may be of only one type, or may be of two or more types.

[0063] When the thermoplastic resin has a crosslinked structure, the gel fraction of the thermoplastic resin foam, as determined in JIS K 6796:1998 using acetone as the extraction solvent, is not particularly limited as long as the requirement for D2 / D1 is satisfied. The gel fraction may be, for example, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less. The gel fraction is typically greater than 0%, and may be 2% or more, 5% or more, 10% or more, or 15% or more. The gel fraction may be within a range that appropriately combines the upper and lower limits.

[0064] (2) Thermoplastic Resin The thermoplastic resin is, for example, one or more selected from the group consisting of thermoplastic polyurethane resin (TPU), thermoplastic polyester elastomer (TPEE), ethylene vinyl acetate copolymer (EVA), thermoplastic styrene elastomer, thermoplastic polyamide elastomer (TPAE), fluororesin, and polyolefin resin. The explanation of these resins is the same as the explanation of each resin in "(2) Thermoplastic Resin" in "2. Thermoplastic Resin Foam" described in embodiment 1.

[0065] The thermoplastic resin is also preferably a dynamically crosslinked thermoplastic elastomer (TPV). The dynamically crosslinked thermoplastic elastomer (TPV) is produced, for example, by crosslinking (dynamically crosslinking) a thermoplastic elastomer (b) and / or a rubber (b) with a thermoplastic resin (a) in a fluid state (dynamic state) of the thermoplastic elastomer (b) and / or the rubber (b). The dynamically crosslinked thermoplastic elastomer (TPV) preferably has a sea-island structure in which particles of the crosslinked thermoplastic elastomer (b) and / or particles of the crosslinked rubber (b) are finely dispersed as domains in a matrix of the thermoplastic resin (a).

[0066] The thermoplastic resin (a) in the dynamically crosslinked thermoplastic elastomer (TPV) may be a crystalline thermoplastic resin, an amorphous thermoplastic resin, or a combination of these. The crystalline thermoplastic resin (a) is, for example, one or more selected from the group consisting of olefin-based resins (PO), polyacetal resins (POM), polyamide-based resins (PA), and polyester-based resins. Examples of polyester-based resins include polyethylene terephthalate (PET) and polybutylene terephthalate (PBT). The amorphous thermoplastic resin (a) is, for example, one or more selected from the group consisting of polystyrene-based resins (PS), polycarbonate-based resins (PC), and polyvinyl chloride-based resins (PVC). The thermoplastic resin (a) in the dynamically crosslinked thermoplastic elastomer (TPV) may be one type only, or two or more types. The amount of thermoplastic resin (a) is preferably 30 parts by mass or more and 300 parts by mass or less, and more preferably 50 parts by mass or more and 200 parts by mass or less, per 100 parts by mass of the total of thermoplastic elastomer (b) and / or rubber (b).

[0067] The thermoplastic elastomer (b) in the dynamically crosslinked thermoplastic elastomer (TPV) is, for example, one or more selected from the group consisting of styrene-based thermoplastic elastomers (TPS), hydrogenated styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers (TPO), polymerized thermoplastic polyolefin-based elastomers (R-TPO), vinyl chloride-based thermoplastic elastomers (TPVC), polyurethane-based thermoplastic elastomers (TPU), polyester-based thermoplastic elastomers (TPC), polyamide-based thermoplastic elastomers (TPA), polybutadiene-based thermoplastic elastomers, fluorine-based thermoplastic elastomers (TPF), and ethylene / α-olefin-based copolymer elastomers. Examples of hydrogenated styrene-based thermoplastic elastomers include hydrogenated styrene-ethylene-propylene-based copolymers (SEP), hydrogenated styrene-ethylene-propylene-styrene-based copolymers (SEPS), and hydrogenated styrene-ethylene-butadiene-based copolymers (SEBS). The thermoplastic elastomer (b) in the dynamically crosslinked thermoplastic elastomer (TPV) may be one type or two or more types.

[0068] The rubber (b) in the dynamically crosslinked thermoplastic elastomer (TPV) can be any of a variety of rubber polymers that are generally crosslinked (vulcanized) before use (i.e., crosslinkable). The rubber (b) can be, for example, one or more selected from the group consisting of natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), butyl rubber (IIR), nitrile rubber (NBR), ethylene propylene rubber (EPM), ethylene propylene diene rubber (EPDM), chloroprene rubber (CR), and acrylic rubber (ACM). The rubber (b) in the dynamically crosslinked thermoplastic elastomer (TPV) can be one or more types.

[0069] The thermoplastic elastomer (b) and / or the rubber (b) can be crosslinked using a crosslinking agent. The crosslinking agent is not particularly limited. Examples of the crosslinking agent include one or more selected from the group consisting of organic peroxides, phenolic resin crosslinking agents, sulfur, sulfur compounds, p-quinone, p-quinone dioxime derivatives, bismaleimide compounds, epoxy compounds, silane compounds, amino resins, polyol crosslinking agents, polyamines, triazine compounds, and metal soaps.

[0070] 2. Requirements for D2 / D1 The vehicle seat pad of this embodiment has an apparent density D1 kg / m measured by taking a test piece of 100 mm x 100 mm x 10 mm from a thermoplastic resin foam. ３ The test piece was heat-pressed for 1 minute at a temperature at which the uncrosslinked thermoplastic resin, which is the raw material of the thermoplastic resin foam, melts under the condition of 30 kPa, and the apparent density of the test piece after heat pressing was D2 kg / m ３ In this case, the relationship 3.5≦D2 / D1 is satisfied. The term "uncrosslinked thermoplastic resin" mentioned above includes not only the case where the thermoplastic resin as a raw material is crosslinked later, but also the case where the thermoplastic resin as a raw material is not crosslinked later.

[0071] The vehicle seat pad more preferably satisfies 4.0≦D2 / D1, and even more preferably 4.5≦D2 / D1. There is no particular upper limit for D2 / D1. The vehicle seat pad usually satisfies D2 / D1≦20.0, and may also satisfy D2 / D1≦15.0 or D2 / D1≦10.0.

[0072] In this disclosure, the "temperature at which the uncrosslinked thermoplastic resin, which is the raw material for the thermoplastic resin foam, melts" refers to a temperature equal to or higher than the melting temperature determined by heat flux differential scanning calorimetry (heat flux DSC) of the uncrosslinked thermoplastic resin, but lower than the decomposition temperature. More specifically, when the uncrosslinked thermoplastic resin contains a crystalline resin and exhibits a melting point when subjected to heat flux differential scanning calorimetry, the melting temperature usually refers to the melting point. When the uncrosslinked thermoplastic resin does not substantially contain a crystalline resin and exhibits only a glass transition temperature when subjected to heat flux differential scanning calorimetry, the melting temperature usually refers to the glass transition temperature. Note that, even if a polymer having a hard segment, such as a thermoplastic polyurethane resin (TPU), is not generally recognized as a crystalline resin, a melting point due to the hard segment may be observed in heat flux differential scanning calorimetry. When the uncrosslinked thermoplastic resin contains such a polymer, the melting temperature refers to the melting point. That is, among transition temperatures such as "glass transition temperature" and "melting point" that appear when heat flux differential scanning calorimetry is performed on an uncrosslinked thermoplastic resin, the thermal melting temperature generally refers to the transition temperature observed on the highest temperature side. Here, "melting point" and "glass transition temperature" can be determined by the method specified in JIS K7121-1987 "Method for Measuring Transition Temperature of Plastics," and are determined by measurement at a heating rate of 10°C / min. Note that "melting point" refers to the "peak melting temperature" in the above standard, and "glass transition temperature" refers to the "midpoint glass transition temperature" in the above standard. The thermal melting temperature of a dynamically crosslinked thermoplastic elastomer (TPV) is determined primarily by the "melting point" and "glass transition temperature" of the thermoplastic resin (a) that constitutes the matrix. A dynamically crosslinked thermoplastic elastomer (TPV) does not melt entirely at the above temperatures, and such temperatures are also referred to as processing temperatures, etc.

[0073] Typically, when a 100 mm x 100 mm x 10 mm non-crosslinked thermoplastic resin foam is heat-pressed at the above temperature for 1 minute under conditions of 30 kPa, the thermoplastic resin melts, and the cell structure becomes invisible to the naked eye. Even when the thermoplastic resin foam has a crosslinked structure, if the crosslink density is sufficiently low, the thermoplastic resin melts by the heat press, and all or most of the cell structure becomes invisible to the naked eye. Even when the thermoplastic resin foam has a crosslinked structure, if the thermoplastic resin is a dynamically crosslinked thermoplastic elastomer (TPV), the thermoplastic resin melts by the heat press, and all or most of the cell structure becomes invisible to the naked eye. The fact that the thermoplastic resin melts by the heat press and all or most of the cell structure becomes invisible to the naked eye is one indicator that the thermoplastic resin foam can be heat-melted and material-recyclable.

[0074] The value of D2 / D1 is determined depending on the expansion ratio of the thermoplastic resin foam, the molten state of the thermoplastic resin due to heat pressing, and the like. For example, the higher the expansion ratio of the thermoplastic resin foam, the smaller the value of D1. Therefore, the value of D2 / D1 tends to increase by increasing the expansion ratio of the thermoplastic resin foam. Furthermore, the value of D2 increases, for example, when the thermoplastic resin is sufficiently melted at the above-mentioned temperature, due to the collapse of the cell structure. Therefore, the value of D2 / D1 tends to increase by decreasing the crosslink density and / or using a dynamically crosslinked thermoplastic elastomer (TPV) as a raw material. In other words, if the value of D2 / D1 is equal to or greater than the above-mentioned lower limit, it can be determined that the expansion ratio of the thermoplastic resin foam is sufficiently high and that the thermoplastic resin foam is in a sufficiently molten state at the above-mentioned temperature.

[0075] The apparent density D1 of the test piece before heat pressing can be measured in accordance with JIS K7222:2005. The apparent density D1 of the test piece before heat pressing is usually approximately the same as the apparent density of the thermoplastic resin foam. The apparent density D1 of the test piece before heat pressing is 30 kg / m ３ More than 200kg / m ３ Preferably less than 80 kg / m ３More than 180kg / m ３ More preferably, 130 kg / m or less ３ More than 150kg / m ３ The following is even more preferred:

[0076] The apparent density D2 of the test piece after heat pressing can be measured, for example, as follows. First, a sample of a predetermined size (for example, 200 mm × 200 mm) is taken from the test piece after heat pressing. The mass (g, 10 －３ kg) and thickness (mm). The volume of the sample (mm) is calculated from the measured thickness x 200 mm x 200 mm. ３ , 10 －９ m ３ The measured mass is divided by the volume to determine the density of the sample (kg / m ３ ) is calculated.

[0077] The apparent density D2 of the test piece after heat pressing is determined depending on the type of uncrosslinked thermoplastic resin that is the raw material of the thermoplastic resin foam and the proportion of cell structures remaining after heat pressing. The apparent density D2 of the test piece after heat pressing is usually equal to or less than the density of the unfoamed thermoplastic resin that is the raw material of the thermoplastic resin foam. The upper limit of the apparent density D2 of the test piece after heat pressing is, for example, 2000 kg / m ３ Preferably, 1500 kg / m or less ３ More preferably, 1200 kg / m or less ３ The lower limit of the apparent density D2 of the test piece after heat pressing is not particularly limited. The lower limit of the apparent density D2 of the test piece after heat pressing is, for example, 800 kg / m ３ More than 900 kg / m ３ More preferably, 950 kg / m or more ３ The above is more preferable.

[0078] 3. Effects of the Present Embodiment The effects of the present embodiment will be described. A thermoplastic resin foam satisfying the above-described requirements D2 / D1 can be suitably recycled as a thermoplastic resin. However, conventional thermoplastic resin foams satisfying the requirements D2 / D1 have difficulty in ensuring various physical properties such as hardness and impact resilience, and their application to seat pads has not been specifically considered. The present inventors have discovered a new thermoplastic resin foam that satisfies the requirements D2 / D1 and has excellent physical properties, and have developed the technology of the present disclosure to apply this to seat pads. The seat pad of the present embodiment is composed of a thermoplastic resin foam that satisfies the requirements D2 / D1, and therefore has excellent recyclability.

[0079] Furthermore, a conventional technique for applying thermoplastic resin to seat pads has been developed, in which thermoplastic resin filaments are wound and fused at their contact points to form a three-dimensional network structure. Such three-dimensional network structures are believed to be lightweight and have high resilience. However, three-dimensional network structures differ from ride comfort achieved by a fine cell structure and are not necessarily suitable for seat pads. In contrast, the seat pad of this embodiment is made of a thermoplastic resin foam, and therefore ride comfort can be ensured by the fine cell structure.

[0080] <Embodiment 3> A vehicle interior member 201 of Embodiment 3 is a vehicle interior member made of a non-crosslinked thermoplastic resin foam. Embodiment 3 differs from Embodiment 1 in that the article made of a non-crosslinked thermoplastic resin foam is a vehicle interior member. With respect to the non-crosslinked thermoplastic resin foam of Embodiment 3, the descriptions of "2. Thermoplastic resin foam" and "3. Physical properties of thermoplastic resin foam" described in Embodiment 1 apply as is, except for the description related to the seat pad, and detailed description thereof will be omitted.

[0081] Examples of vehicle interior components include door trim, console box, seat bag garnish, instrument panel, ceiling material, seat pad, ceiling cushion material, sound absorbing material, soundproofing material, headrest, armrest, floor mat, trunk mat, floor spacer, door mirror gasket, pillar garnish, engine sound absorbing material, fuel tank safety foam, in-filter material, element material, side impact pad, door panel, seat back cover, instrument panel skin, steering wheel, car air conditioner insulation material, instrument panel lining material, trunk mat, wheel house cover, sun visor, molded door, pillar trim, wiring protector, assist grip, etc. Figure 2 is a partial cross-sectional view of a vehicle interior component 201. The arrow IN indicates the interior side of the vehicle cabin. The upper surface of the vehicle interior component 201 corresponds to the surface on the interior side of the vehicle cabin.

[0082] The vehicle interior member 201 may have an uncrosslinked thermoplastic resin foam exposed on its surface facing the interior of the vehicle cabin. Uncrosslinked thermoplastic resin foams have a better appearance than, for example, thermosetting polyurethane foams, and when they have a surface skin, they are less likely to fall off due to friction, such as when touched by a person. Therefore, uncrosslinked thermoplastic resin foams are also suitable as components that form the surface of the vehicle interior member 201. Furthermore, when uncrosslinked thermoplastic resin foams form the surface of the vehicle interior member 201, the thermoplastic resin foam may have an uneven surface from the viewpoint of improving design and / or anti-slip properties. Examples of such uneven surfaces include so-called grain patterns and dot patterns.

[0083] The vehicle interior member may include a non-crosslinked thermoplastic resin foam and a skin material (not shown) provided on the interior surface of the thermoplastic resin foam facing the vehicle cabin. When the vehicle interior member includes a skin material, the thermoplastic resin foam may be directly bonded to the skin material. Such a vehicle interior member can be manufactured by integrally molding the non-crosslinked thermoplastic resin foam and the skin material. Alternatively, the vehicle interior member can be manufactured by molding the non-crosslinked thermoplastic resin foam, partially melting the surface, and directly bonding the skin material.

[0084] The effects of this embodiment will be described. Non-crosslinked thermoplastic resin foams can be suitably recycled as thermoplastic resins. However, it is difficult to ensure various physical properties such as hardness and impact resilience with conventional non-crosslinked thermoplastic resin foams, and their application to vehicle interior components has not been specifically considered. The present inventors have newly discovered a non-crosslinked thermoplastic resin foam with excellent physical properties and have developed the technology of the present disclosure for applying this to vehicle interior components. Since the vehicle interior component of this embodiment is made of a non-crosslinked thermoplastic resin foam, it has excellent recyclability.

[0085] <Other Embodiments> The vehicle seat pad of the present disclosure is not limited to the automobile seat pad 10 of a separate seat as shown in Fig. 1. The vehicle seat pad may be an automobile seat pad of a bench seat.

[0086] The vehicle seat pad of the present disclosure may be a motorcycle seat pad 110 constituting a motorcycle seat as shown in Fig. 3. The motorcycle seat includes, for example, the seat pad 110 and a trim cover (not shown) that covers the outer surface of the seat pad 110. An arrow FR appropriately shown in Fig. 3 indicates the forward direction of the motorcycle seat (the direction in which the seated person faces), and an arrow RR indicates the rearward direction of the motorcycle seat. An arrow UP indicates the upward direction of the motorcycle seat, and an arrow DW indicates the downward direction of the motorcycle seat.

[0087] The vehicle seat pad may also be any of a seat pad constituting a seat for a railway vehicle, a seat pad constituting a seat for a ship, and a seat pad constituting a seat for an airplane.

[0088] In the case of the above-mentioned embodiment 3, the thermoplastic resin foam may have a crosslinked structure. For example, the vehicle interior material of another embodiment may be the vehicle interior material made of the thermoplastic resin foam described in the section on the seat pad of embodiment 2. The vehicle interior material of another embodiment has an apparent density D1 kg / m measured by taking a test piece of 100 mm × 100 mm × 10 mm from the thermoplastic resin foam. ３The test piece was heat-pressed for 1 minute at a temperature at which the uncrosslinked thermoplastic resin, which is the raw material of the thermoplastic resin foam, melts under the condition of 30 kPa, and the apparent density of the test piece after heat pressing was D2 kg / m ３ In this case, the relationship 3.5≦D2 / D1 may be satisfied.

[0089] The following provides a more detailed explanation using examples. 1. Preparation of Example Samples (1) Example 1 (Injection Foaming Method) The following thermoplastic polyurethane resin 1 and nitrogen gas present as a supercritical fluid were mixed in the screw of an injection molding machine to prepare a resin mixture. The resin mixture was injected into a mold to prepare a rectangular parallelepiped uncrosslinked thermoplastic resin foam sample measuring 200 mm in length, 200 mm in width, and 20 mm in height. A Nexcell (registered trademark) SCF foam elastomer injection molding machine manufactured by KINGSTEEL was used for preparation. Example 1 corresponds to a molded thermoplastic resin foam. Thermoplastic polyurethane resin 1 (manufactured by BASF, product number ELASTOLLAN SP 9552)

[0090] The density of Example 1 was measured in accordance with JIS K7222:2005. The density of Example 1 was 150 kg / m ３ It was.

[0091] The compressive stress of Example 1 was measured in accordance with the method described in Embodiment 1. The compressive stress of Example 1 was 100 N / diameter of 50 mm.

[0092] The 25% compression hardness of Example 1 was measured in accordance with JIS K6400-2:2012 Method D. The 25% compression hardness of Example 1 was 120 N / diameter 50 mm.

[0093] The impact resilience of Example 1 was measured in accordance with JIS K 6400-3: 2011. The impact resilience of Example 1 was 60%.

[0094] (2) Example 2 (Batch Foaming Method 1) The following thermoplastic polyurethane resin 2 was impregnated with a mixture of carbon dioxide and nitrogen gases present as a supercritical fluid in an autoclave under the following conditions: below the softening point temperature of the resin, at a pressure of 5 to 15 MPa, and for an impregnation time of 3 to 5 hours. The impregnated mixture was then expanded by heating above the softening point temperature of the resin and releasing to normal pressure, thereby obtaining a sample of non-crosslinked thermoplastic resin foam. The sample was a rectangular parallelepiped measuring 1900 mm in length, 1220 mm in width, and 23 mm in height. Thermoplastic polyurethane resin 2 (manufactured by BASF, product number C65HPM)

[0095] The density of Example 2 was measured in accordance with JIS K7222:2005. The density of Example 2 was 100 kg / m ３ It was.

[0096] The compressive stress of Example 2 was measured in accordance with the method described in Embodiment 1. The compressive stress of Example 2 was 80 N / diameter of 50 mm.

[0097] The 25% compression hardness of Example 2 was measured in accordance with JIS K6400-2:2012 Method D. The 25% compression hardness of Example 2 was 100 N / diameter 50 mm.

[0098] The impact resilience of Example 2 was measured in accordance with JIS K 6400-3: 2011. The impact resilience of Example 2 was 58%.

[0099] (3) Example 3 (Batch Foaming Method 2) Thermoplastic polyester elastomer (TPEE) 1 was impregnated with a mixture of carbon dioxide and nitrogen gases present as a supercritical fluid in an autoclave under the following conditions: a temperature below the softening point of the resin, a pressure of 5 to 15 MPa, and an impregnation time of 3 to 5 hours. The mixture was then heated to above the softening point of the resin and released to normal pressure, expanding the impregnated mixture and obtaining a sample of uncrosslinked thermoplastic resin foam. The sample was a rectangular parallelepiped measuring 1300 mm in length, 1100 mm in width, and 24 mm in height. Thermoplastic polyester elastomer (TPEE) 1 (manufactured by Celanese, product number FM8782)

[0100] The density of Example 3 was measured in accordance with JIS K7222:2005. The density of Example 3 was 165 kg / m ３ It was.

[0101] The compressive stress of Example 3 was measured in accordance with the method described in Embodiment 1. The compressive stress of Example 3 was 90 N / diameter of 50 mm.

[0102] The 25% compression hardness of Example 3 was measured in accordance with JIS K6400-2:2012 Method D. The 25% compression hardness of Example 3 was 150 N / diameter 50 mm.

[0103] The impact resilience of Example 3 was measured in accordance with JIS K 6400-3: 2011. The impact resilience of Example 3 was 70%.

[0104] (4) Examples 4 to 6 (Batch Foaming Method 1) Thermoplastic polyurethane resin 3 was prepared. Samples were produced in the same manner as in Example 2, except that the mass of thermoplastic polyurethane resin 3 before impregnation with nitrogen gas was adjusted so as to have the density shown in Table 2.

[0105] (5) Examples 7 and 8 (Injection Foaming Method) Thermoplastic polyurethane resin 4 was prepared. Samples were produced in the same manner as in Example 1, except that the mixing ratio of thermoplastic polyurethane resin 4 to nitrogen gas, molding temperature, and pressure were adjusted so as to obtain the density shown in Table 3. Examples 7 and 8 correspond to molded thermoplastic resin foams.

[0106] (6) Example 9 (Batch Foaming Method 2) A thermoplastic polyester elastomer (TPEE) 2 was prepared. A sample was produced in the same manner as in Example 3, except that the mass of the thermoplastic polyester elastomer (TPEE) 2 before impregnation with nitrogen gas was adjusted so as to have the density shown in Table 3.

[0107] (7) Example 10 (Batch Foaming Method 1) A dynamically crosslinked thermoplastic elastomer (TPV) was prepared. A primary foam of a thermoplastic resin foam having a crosslinked structure was produced in the same manner as in Example 2, except that the mass of the dynamically crosslinked thermoplastic elastomer (TPV) before impregnation with nitrogen gas was adjusted so as to have the density shown in Table 3. The primary foam was subjected to thermocompression molding in the same manner as in Example 2 to produce a sample.

[0108]

[0109]

[0110] 2. Evaluation (1) Density The apparent density of each example was measured in accordance with JIS K7222:2005. A test piece measuring 100 mm x 100 mm x 10 mm was taken from the thermoplastic resin foam of each example, and the apparent density D1 (kg / m ３) was measured. (2) Compressive Stress The compressive stress of each Example was measured in accordance with the method described in Embodiment 1. (3) 25% Compression Hardness The 25% compression hardness of each Example was measured in accordance with JIS K6400-2:2012 D Method. (4) Rebound Resilience The rebound resilience of each Example was measured in accordance with JIS K 6400-3:2011. (5) Gel Fraction The gel fraction in JIS K 6796:1998 was measured using acetone as the extraction solvent. (6) Tear Strength The tear strength of each Example was measured in accordance with JIS K 6400-5:2012. (7) Compressive Set (Dry Heat Strain) The compressive set (dry heat strain) of each Example was measured in accordance with JIS K6400-4:2004 4.5 A Method (Dry Heat Strain). The compressive set was calculated by compressing each sample to 75% of its original thickness and measuring the thickness of the test piece after 22 hours of testing at 70°C. (8) Wet Heat Compressive Set The wet heat compressive set of each example was measured in accordance with JIS K6400-4:2004. The wet heat compressive set was calculated by compressing each sample to 70% of its original thickness and measuring the thickness of the test piece after 22 hours of testing at 50°C and 95% relative humidity. (9) 25% Hardness Change Rate and 50% Hardness Change Rate The 25% hardness change rate and 50% hardness change rate of each example were measured in accordance with the method described in embodiment 1. (10) Average Cell Diameter The average cell diameter of each example was measured in accordance with the method described in embodiment 1. (11) Requirements for D2 / D1 The test pieces for which the apparent density D1 was measured were heat-pressed at 200°C for 1 minute at 30 kPa. The apparent density D2 (kg / m) of the obtained test piece after heat pressing ３ ) was measured in accordance with the method described in embodiment 2. D2 / D1 was calculated for each example, and the recyclability of each example was evaluated based on the following criteria: "A": Satisfies 3.5≦D2 / D1. "B": Does not satisfy 3.5≦D2 / D1.

[0111] 3. Results The evaluation results are shown in Tables 1 to 3. In Examples 1, 2, and 3, thermoplastic resin foams could be obtained without undergoing a crosslinking step. In Examples 1, 2, and 3, the thermoplastic resin foams were non-crosslinked and therefore had excellent recyclability. In Examples 1, 2, and 3, the thermoplastic resin foams satisfied 3.5≦D2 / D1 and therefore had excellent recyclability.

[0112] Examples 1, 2, and 3 had physical properties suitable for vehicle seat pads. Examples 1, 2, and 3 ensured ride comfort. In particular, Example 1 had hardness suitable for the side portions of the seat cushion. Example 3 had hardness suitable for the side portions of the seat back. When Example 2 is used in the seat cushion and / or seat back side portions, even better ride comfort can be ensured.

[0113] Furthermore, in Examples 4 to 9, thermoplastic resin foams could be obtained without undergoing a crosslinking step. Examples 4 to 9 are non-crosslinked thermoplastic resin foams, and therefore have excellent recyclability. In Example 10, a thermoplastic resin foam was obtained using a dynamically crosslinked thermoplastic elastomer (TPV). Examples 1 to 10 are thermoplastic resin foams that satisfy 3.5≦D2 / D1, and therefore have excellent recyclability.

[0114] Examples 1 to 10 had physical properties suitable for vehicle seat pads, and were able to ensure ride comfort.

[0115] The present disclosure is not limited to the above-described embodiments, and various modifications and variations are possible.

[0116] DESCRIPTION OF SYMBOLS 1 ... Vehicle seat 10A, 10B, 10C ... Seat pad 11A, 11B ... Main part 13A, 13B ... Side part 110 ... Seat pad 201 ... Vehicle interior member

Claims

1. A vehicle seat pad made of non-crosslinked thermoplastic resin foam.

2. A vehicle seat pad made of a thermoplastic resin foam, wherein the apparent density measured by taking a 100mm x 100mm x 10mm test piece from the thermoplastic resin foam is D1kg / m ３ The test piece is heat-pressed for 1 minute under a condition of 30 kPa at a temperature at which the uncrosslinked thermoplastic resin, which is a raw material of the thermoplastic resin foam, melts, and the apparent density of the test piece after heat pressing is D2 kg / m ３ A vehicle seat pad that satisfies 3.5≦D2 / D1 when 3. The apparent density of the thermoplastic resin foam is 200 kg / m ３ 3. The vehicle seat pad according to claim 1 or 2, wherein:

4. A vehicle seat pad as described in claim 1 or claim 2, wherein when a pressing surface of a pressure tool including a circular pressing surface with a diameter of 50 mm is applied to the surface of the vehicle seat pad and the vehicle seat pad is compressed at a speed of 50 mm / min, the compressive stress of the thermoplastic resin foam at a depth of 3 mm from the surface is 100 N / diameter 50 mm or less.

5. A vehicle seat pad according to claim 1 or 2, wherein the 25% compression hardness of the thermoplastic resin foam measured in accordance with JIS K6400-2:2012 Method D is 700 N / diameter 50 mm or less.

6. A vehicle seat pad according to claim 1 or 2, wherein the thermoplastic resin foam has a rebound resilience of 50% or more and 80% or less, measured in accordance with JIS K 6400-3:2011.

7. The vehicle seat pad according to claim 1 or 2, wherein the thermoplastic resin foam is molded.

8. Vehicle interior components made of non-crosslinked thermoplastic resin foam.

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