JPH079485A - Production of automotive interior trim made of composite molded body - Google Patents

Abstract

PURPOSE:To obtain an automotive interior trim having a superior soft feeling, a high hardness, and a high-quality feeling by a method wherein a mold capacity is increased after a substrate is injection molded, or a substrate is inserted in a mold, and a specific foamable styrene thermoplastic elastomer composition is injected, thereafter being foamed by increasing a mold capacity. CONSTITUTION:A substrate for an automotive interior trim is molded out of a thermoplastic resin and inserted in a mold. Alternatively, a mold capacity is increased after a substrate is injection molded. Next, a foamable styrene thermoplastic elastomer composition is injected. After a full shot, the composition is foamed by increasing a mold capacity. The thermoplastic elastomer composition in use is prepared by compounding 0.5-10 pts.wt. foaming agent component with 100 pts.wt. of a composition based on a hydrogenated styrene- conjugated diene block copolymer with a metal tension 1.5kg or more at 190 deg.C, a melt spreadability of 100m/min or more, and an A hardness of 30-95 by JIS-K6301.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of automobile interior parts made of a composite molded article obtained by coating a thermoplastic resin substrate with a surface layer made of a styrene thermoplastic elastomer foam. It is about the method.
Specifically, a composite molding having a good multi-layered structure composed of a base material having rigidity and strength required for interior parts for automobiles and a surface layer material which covers the base material and provides a stable feel. The present invention relates to a method of manufacturing an automobile interior component represented by an instrument panel and its peripheral components, a door trim, a pillar garnish, etc.

[0002]

2. Description of the Related Art Instrument panels, door trims,
Interior parts for automobiles such as pillar garnishes, especially instrument panels, are required to have a soft feeling from the viewpoint of high quality and safety, and are composed of a composite using different resins to meet the needs. ing. As a typical example of such a composite, a polyvinyl chloride sheet is used for the surface layer, a foam such as polyurethane or polypropylene is used for the cushion layer, and the base material is a multilayer structure formed of a hard thermoplastic resin. Is known. Further, as a method for forming such a composite molded body having a multilayer structure, a sticking method, a slush method, an injection compression method and the like are particularly adopted.

[0003]

However, the automobile interior parts obtained by these construction methods are all obtained from a combination of a plurality of materials and construction methods.
It has the following problems (1) to (3). (1) Production efficiency is low due to the large number of manufacturing processes. (2) The material yield is poor. (3) Recycling is difficult. Therefore, as an attempt to solve the above problems, a method has been proposed in which a thermoplastic resin is used as a base material and a styrene elastomer composite molded body is used as a surface layer material by double-layer injection molding. A typical one of them is JP-A-61-2.
13145, JP-A-63-254015,
It is known as Japanese Patent Laid-Open No. 1-249416.
However, although these methods can solve various problems in the process necessary for obtaining automobile interior parts, the foaming degree required for the surface layer material to be non-foamed or to obtain an appropriate soft feeling is obtained. Since it does not have it, it is not always satisfactory in terms of softness and weight reduction of the obtained product, and its commercial value is lower than conventional pasting method, slush method and injection compression method. I could only get things. Therefore, the present invention solves the problems of the conventional two-layer injection molded composite molded article by continuously and stably forming the foam required for the surface layer material to have an appropriate soft feeling. It is an object of the present invention to provide a method of manufacturing an automobile interior part that can be manufactured.

[0004]

[Means for Solving the Problems]

[Summary of the Invention] The inventors of the present invention have conducted extensive studies in view of the problems associated with the above-mentioned conventional methods, and as a result, have selected a thermoplastic resin as a base material and a specific styrene elastomer foam as a surface layer material. The molded body of the base material is inserted into the mold, or the base material is injection-molded, and the foamable styrene elastomer is fully shot into the voids in the restricted mold, and then the mold is used. The present invention has been completed by finding that the above object can be achieved by increasing the volume of the above. That is, the method for producing an automobile interior part made of the composite molded article of the present invention is to inject a thermoplastic resin into a void portion in a mold in which a separately molded thermoplastic resin molded product is mounted, or in the mold. After molding, in the void portion in the mold provided by expanding the internal volume of the mold, (a) based on the hydrogenated styrene-conjugated diene block copolymer, the melt tension at 190 ℃ 1.5 g or more, melt spreadability of 100 m / min or more, and
JIS-A hardness according to JIS-K6301 is 30 to 95
Styrene thermoplastic elastomer component
After injecting a foamable styrene-based thermoplastic elastomer composition comprising 100 parts by weight and (b) 0.5 to 10 parts by weight of a foaming agent component, the internal volume of the mold is expanded to obtain the expandable styrene. It is characterized by foaming and integrating a thermoplastic thermoplastic elastomer composition.

[Detailed Description of the Invention] [I] Raw material (1) Base material (a) Thermoplastic resin Base material for automobile interior parts used in a method for producing automobile interior parts comprising the composite molded article of the present invention As the thermoplastic resin, a thermoplastic resin that can satisfy mechanical properties such as rigidity and strength, heat resistance and durability required for interior parts for automobiles is used. Specific examples of such a thermoplastic resin include polyolefin resins such as polypropylene and polyethylene, polystyrene, acrylonitrile
Injection molding of styrene copolymers, styrene resins such as acrylonitrile-butadiene-styrene copolymers, polyamide resins such as nylon 6 and nylon 66, engineering resins such as polyoxymethylene and modified polyphenylene ether, etc. is possible. It is a resin. Among the above-mentioned thermoplastic resins, polyolefin-based resins and styrene-based resins are preferably used from the viewpoints of compatibility with the surface layer material, lightness and recyclability. Among these, a propylene-based resin having excellent moldability and mechanical properties, or a composite propylene-based resin described below in which a reinforcing material is mixed, is preferably used. These thermoplastic resins can be used alone or as a blend of a plurality of types.

(B) Other compounding materials The above-mentioned thermoplastic resin is used in order to improve the product quality, rubber,
It is also possible to use a composite resin in which a reinforcing material such as an inorganic filler or glass fiber is mixed. Further, if necessary, a core material such as steel can be inserted therein. In the above-mentioned thermoplastic resin, a colorant, an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, a neutralizing agent, a lubricant, an antifogging agent, an antibacterial agent, if necessary, within a range not impairing the object of the present invention. Additives such as blocking agents, slip agents, dispersants and antistatic agents can be added.

(2) Surface layer material (expandable styrene-based thermoplastic elastomer composition) In order to form the surface layer part formed on the above-mentioned substrate in the method for producing an automobile interior part comprising the composite molded article of the present invention. As a surface layer material, it is excellent in molding processability such as foaming moldability, can obtain the foaming ratio necessary for expressing a high-grade soft feeling, and is free of swirl marks (swirl marks) on its surface. A foamable styrene-based thermoplastic elastomer composition is used which has excellent foaming appearance such as having smoothness and can maintain a stable cell structure and foaming appearance even when continuously molded. .

Constituents Such expandable styrene thermoplastic elastomer composition has a melt tension at 190 ° C. of not less than 1.5 g based on (a) a hydrogenated product of a styrene / conjugated diene block copolymer, Melt spreadability is 100 m / min or more, and
JIS-A hardness according to JIS-K6301 is 30 to 95
Styrene thermoplastic elastomer component
100 parts by weight, and (b) 0.5 to 10 parts by weight of the foaming agent component.

Physical properties Further, the physical properties are such that the melt tension at 190 ° C. by the measuring method described later is 1.5 g or more, preferably 1.6 g or more, particularly preferably 1.8 g or more, and the spreadability is 100 m / min or more, preferably Is 120 m / min or more, particularly preferably 15
0 m / min or more and JIS according to JIS-K6301
-A hardness of 30 to 95, preferably 50 to 90, especially 7
0 to 90. When the JIS-A hardness is 70 or more, it is possible to obtain the foamed composite required to obtain a high degree of softness, and the occupant protection method against in-vehicle impact or human contact represented by EC E21 is installed. This is preferable because it can be satisfied without being restricted by the shape of the interior parts for automobiles including the ment panel. If the melt tension and the spreadability are less than the above range, the expansion ratio is insufficient, and the soft feeling as a surface layer material for automobile interior parts is poor and the touch is inferior. Inferior in stability. Furthermore, the above JIS-K630
When the JIS-A hardness according to 1 is less than the above range, the injection moldability and mechanical strength are poor. Also, JIS
If the -A hardness exceeds the above range, the soft feeling after foaming is poor and the touch is poor.

(A) Styrene-based thermoplastic elastomer component (styrene-based TPE component) A styrene-based thermoplastic elastomer component (hereinafter simply referred to as "styrene-based TPE component") which is a constituent component of the expandable styrene-based thermoplastic elastomer composition. ) Is a styrene-based compound obtained by block-copolymerizing a styrene-based monomer such as styrene, α-methylstyrene, paramethylstyrene and a conjugated diene monomer such as butadiene and isoprene. Styrene obtained by further hydrogenating a block copolymer having both a styrene-based polymer block mainly containing a monomer and a conjugated diene-based polymer block mainly containing a conjugated diene monomer -Based on a hydrogenated product of a conjugated diene block copolymer.

Of styrene / conjugated diene block copolymer
Hydrogenated product The hydrogenated product of the styrene / conjugated diene block copolymer is, for example, a styrene / butadiene block copolymer hydrogenated product, or a styrene / isoprene block copolymer hydrogenated product, or a mixture thereof. Is. Specifically, a styrene / ethylene / butylene / styrene copolymer (a hydrogenated product of a styrene / butadiene block copolymer: hereinafter sometimes simply abbreviated as “SEBS”) or styrene / ethylene / propylene /
Examples thereof include a styrene copolymer (hydrogenated product of styrene / isoprene block copolymer: hereinafter sometimes simply referred to as “SEPS”), or a mixture thereof. The hydrogenated products of these styrene / conjugated diene block copolymers have an average molecular weight of 50,000 to 300,
000, preferably 50,000 to 130,000, styrene content 5 to 50% by weight, preferably 10 to 45
It is preferable to use a block copolymer having a weight% and a hydrogenation rate of 95% or more. If the average molecular weight of the hydrogenated product of the styrene / conjugated diene block copolymer is less than the above range, rubber elasticity and mechanical strength are poor, and if the average molecular weight exceeds the above range, moldability and feel after foaming It is not preferable because it is inferior to.

Measurement of average molecular weight The above average molecular weight is measured by gel permeation chromatography (GP).
C: polystyrene equivalent weight average molecular weight measured by Gel Permeation Chromatgraohy). The average molecular weight is measured by MILLIPORE 150C ALC.
/ GPC, column: AD80M / S (manufactured by Showa Denko KK), 3 solvents, ortho-dichlorobenzene, measurement temperature: 140 ° C, flow rate: 1 ml / min, injection amount: 200μ
1, concentration: 2 mg / ml (antioxidant 2,6-di-t-
Butyl-p-phenol is added in an amount of 0.2% by weight). An infrared spectrophotometer (MIRAN 1A,
(Manufactured by FOXBORO Co., Ltd.) at a wavelength of 3.42 μm. Styrene / ethylene / butylene / styrene copolymer (SEBS), which is a hydrogenated product of these styrene / butadiene block copolymers, or styrene, which is a hydrogenated product of styrene / isoprene block copolymers.
Ethylene / Propylene / Styrene Copolymer (SEPS)
The styrene-based thermoplastic elastomer containing as a base can be obtained from the market as "Lavalon" manufactured by Mitsubishi Petrochemical Co., Ltd., for example. Components other than the hydrogenated substance contained in such a styrene-based thermoplastic elastomer include a hydrocarbon-based rubber softening agent, an olefin polymer and / or a styrene polymer, and other components.

Olefin-based polymer and / or styrene-based polymer
Examples of the polymer olefin-based polymer include polypropylene, polyethylene, and propylene / ethylene copolymers,
Examples of the styrene-based polymer include polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, and the like. Above all, MFR
Is particularly preferable to be a propylene / ethylene block copolymer having a ratio of 4 g / 10 minutes or more. These polymers are preferably added in an amount of 5 to 500 parts by weight, particularly 30 to 250 parts by weight, based on 100 parts by weight of the hydrogenated product of the styrene / conjugated diene block copolymer.

Hydrocarbon-based rubber softening agent The above-mentioned hydrocarbon-based rubber softening agent can play an important role in controlling the processability and flexibility of the styrene-based thermoplastic elastomer composition. Such a hydrocarbon-based rubber softening agent (average molecular weight is generally 3
0 to 1,000, preferably 500 to 1,000) is added in an amount of 0 to 250 parts by weight, particularly 20 to 200 parts by weight, based on 100 parts by weight of the hydrogenated product of the styrene / conjugated diene block copolymer. Preferably. Such a hydrocarbon-based rubber softening agent is a mixture of three aromatic ring, naphthene ring and paraffin ring,
Those in which the number of carbons in the paraffin chain accounts for 50% or more of the total carbons are called paraffinic oils, those in which the naphthene ring carbon number is 30 to 45% are called naphthenic oils, and the aromatic carbon number is more than 30%. Many are classified as aromatic oils. Of these, paraffinic oil is preferably used.

(B) Foaming Agent Component The foaming agent used for foaming the styrene-based thermoplastic elastomer may be organic or inorganic as long as it can foam-mold the styrene-based thermoplastic elastomer by injection molding. Can be used without.
Preferred specific examples of such a foaming agent include azo compounds such as azodicarboxylic acid amide, nitroso compounds such as N, N'-dinitrosopentamethylenetetramine, carbonic acid such as sodium bicarbonate, sodium hydrogencarbonate and ammonium bicarbonate. Examples thereof include salts, organic acids such as citric acid, sodium citrate, and oxalic acid, combinations of carbonates and organic acids, sodium borohydride, and the like. When foam molding is carried out at a relatively high temperature, a thermal decomposition chemical foaming agent such as p, p′-oxybisbenzenesulfonyl semicarbazide, p-toluenesulfonyl semicarbazide, trihydrazinotriazine, barium azodicarboxylate, or Inorganic gases such as nitrogen gas, carbon dioxide gas, freon gas, etc., and organic compounds such as butane, pentane, heptane, etc. can also be used, but generally azodicarboxylic acid amide or a mixture of carbonate and organic acid is used. Preferably.

(C) Additional compounding component (optional component) The expandable styrene-based thermoplastic elastomer composition used as the surface layer material in the method for producing an automobile interior part made of the composite molded article of the present invention includes In addition to the thermoplastic elastomer component and the foaming agent and the above-mentioned olefin-based polymer, styrene-based polymer and hydrocarbon-based rubber softening agent, any compounding component such as an additive or compounding material is compounded according to various purposes. be able to.

Additives As the above-mentioned additives, auxiliary additive components generally used for resin compositions, for example, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, neutralizing agents, lubricants, anti-reflective agents are used. Clouding agent,
Anti-blocking agent, slip agent, colorant, plasticizer,
You may mix a flame retardant, a dispersing agent, an antistatic agent, etc.

Blending Material Furthermore, blending materials such as various thermoplastic resins, various elastomers, glass fibers, glass balloons, and various fillers such as inorganic fillers can be blended within a range that does not significantly impair the effects of the present invention.

Thermoplastic resin As the thermoplastic resin in the above-mentioned additional compounding material component, polyphenylene ether resin, nylon 6, nylon 66
Polyamide resins such as, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyoxymethylene resins such as polyoxymethylene homopolymers and polyoxymethylene copolymers, polymethylmethacrylate resins and the like can be used. These thermoplastic resins may be used alone or as a mixture of plural kinds. These thermoplastic resins are generally 1 to 300 parts by weight, preferably 20 to 25 parts by weight, based on 100 parts by weight of the hydrogenated product of the styrene / conjugated diene block copolymer.
It is preferable to add 0 parts by weight.

(D) Amount Ratio The amount of the foaming agent blended in the expandable styrene-based thermoplastic elastomer composition used as the surface layer material in the method for producing an automobile interior part made of the composite molded article of the present invention is as described above. The amount is 0.5 to 10 parts by weight, preferably 1 to 8 parts by weight, and particularly preferably 2 to 6 parts by weight, based on 100 parts by weight of the styrene-based thermoplastic elastomer component. If the compounding amount of the foaming agent is less than the above range, the expansion ratio will be poor, and if it exceeds the above range, the foaming appearance will be poor.

(E) Production of expandable styrene-based thermoplastic elastomer composition The expandable styrene-based thermoplastic elastomer composition is prepared by mixing the styrene-based thermoplastic elastomer component and the foaming agent component as essential components in the above amount ratio. Can be manufactured. As a method of mixing the foaming agent into the styrene-based thermoplastic elastomer component, a method of adding the foaming agent component when kneading the styrene-based thermoplastic elastomer component material and subjecting it to molding after pelletizing by an extruder, surface layer Alternatively, a foaming agent or a masterbatch thereof (a polyolefin resin or an elastomer containing a high concentration of the foaming agent) may be added at the time of molding. The expandable styrene-based thermoplastic elastomer composition is usually used after being formed into pellets by a commonly used method such as an extruder.

[II] Manufacture of Interior Parts for Automobile Composed of Composite Molded Body (1) Forming Base Material for Interior Parts for Automobile Inside Mold First, a base material for automobile interior parts is formed inside the mold. Such automobile interior part base material is
In order to satisfy the mechanical properties such as rigidity and strength required for automobile interior parts, heat resistance, durability, etc., a molding machine of various shapes is formed in advance by using a thermoplastic resin material to form different molding machines. Or in the previous step when compound molding is performed. As a method of forming the automobile interior part base material inside the mold, the same mold as the mold from which the foamable styrene-based thermoplastic elastomer composition described below is injected is used, and the thermoplastic resin material is used in the previous step. Can be formed by injection molding, but a thermoplastic resin material is separately injection-molded or press-molded in a mold different from the mold into which the expandable styrenic thermoplastic elastomer composition is injected, which will be described later. It can also be formed by mounting an automobile interior component base material, which is formed by performing a molding process, etc., inside a mold.

(A) Injection of thermoplastic resin material Using the same mold as the former mold for injecting the expandable styrene-based thermoplastic elastomer composition described below, the thermoplastic resin material is placed inside the mold. In the case of forming an automobile interior parts base material by injection molding, a foamable styrene-based thermoplastic elastomer composition for forming a surface layer portion described below between the mold and the automobile interior parts base material. In order to be able to inject the (surface layer material), it is necessary to injection-mold the thermoplastic resin material and then increase the inner volume of the mold to provide a gap between the mold and the mold. The expansion of the inner volume of the mold is performed by using a mold capable of moving the partition wall of the mold on the side where the surface layer of the automobile interior part base material is to be formed, and increasing the inner volume of the mold. It is done by doing. The degree of expansion of the mold is appropriately determined according to the degree of wall thickness of the surface layer portion formed by injection of the expandable styrene-based thermoplastic elastomer composition described below.

(B) Mounting of a base material for interior parts for automobiles Further, by using the latter mold different from the mold for injecting the expandable styrene thermoplastic elastomer composition described later,
Separately, when forming by molding and molding a base material for automobile interior parts by injection molding a thermoplastic resin material etc., it is not necessary to expand the inner volume of the mold like the former. It is not necessary to provide a gap between the automobile interior part base material and the mold, but it is necessary to use a mold having an internal volume larger than that of the automobile interior part base material.

(2) Injection of Expandable Styrenic Thermoplastic Elastomer Composition (Surface Layer Material) Next, the expandable styrenic thermoplastic elastomer composition is placed in the space between the automobile interior part substrate and the mold. (Surface layer material) is injected. The expandable styrene thermoplastic elastomer composition (surface layer material) is composed of the styrene thermoplastic elastomer component and a foaming agent component.
The foamable styrene thermoplastic elastomer composition (surface layer material) is generally injected at 180 to 240 ° C., preferably 2
Temperature of 00-220 ° C, generally 400-1,200 kg
/ Cm ² , preferably 600 to 1,000 kg / cm ²
It is a full shot under the pressure of. Although it is not necessary to be a full shot, a short shot may be used, but when a pyrolytic chemical foaming agent is used as a foaming agent and an excessively small amount of the composition is injected with respect to the inner volume of the mold, the foaming agent is used. The gas generated from the gas diffuses out of the system of the elastomer composition to form swirl marks, deteriorating the surface appearance, and it becomes difficult to obtain a satisfactory expansion ratio. The wall thickness of the unfoamed surface layer portion (foamable styrene-based thermoplastic elastomer composition) is generally 1.25 to 3.0 mm, preferably 1.5 to 2.5 mm, particularly preferably 1.8 to
It is about 2.2 mm. When the thickness of the surface layer portion is less than the above range, the temperature of the mold is lower than the crystal starting temperature or the glass transition temperature of the mold, so that the mold is rapidly solidified, and it is difficult to obtain a foam required for a soft feeling. Further, if it exceeds the above range, the wall thickness becomes too thick in order to obtain the density of the surface layer portion required for an appropriate soft feeling, and it takes a long time to cool it, resulting in poor productivity and lack of practicality. . However, for parts that do not require the function or softness as interior parts for automobiles, the mold cavity has a gap of 1.25 mm.
Less than one can also be used.

(3) Expansion / Bubbling / Integration of Mold Inner Volume Next, the mold inner volume is expanded. The expansion of the inner volume of the mold is usually carried out by moving the partition wall of the mold on the side of the injected expandable styrene-based thermoplastic elastomer composition. The expandable styrene-based thermoplastic elastomer composition (surface layer material) injected into the space between the automobile interior part substrate and the mold expands the inner volume of the mold after filling the space. By doing so, the unfoamed expandable styrene-based thermoplastic elastomer composition (surface layer material) is foamed to form a surface layer portion having a uniform cell structure. Then, the expansion of the internal volume of the mold is stopped when the foaming ratio reaches a predetermined level, and the expandable styrene-based thermoplastic elastomer composition (surface layer material) and the automobile interior part base material are integrated. Thus, it is possible to manufacture an automobile interior part made of a composite molded body in which peeling between the base material and the surface layer portion is prevented. The expansion of the inner volume of the mold is determined by the degree of expansion ratio. The expansion ratio is generally 1.5-
It is 4 times, preferably 1.5 to 2.5 times. When an expandable styrene-based thermoplastic elastomer composition is injected without expanding the inner volume of the mold to form an automobile interior part (base material), the expandable styrene is expanded under high pressure in a cold mold. The thermoplastic thermoplastic elastomer composition (surface layer material) must be injection-molded, and in this case, it is also possible to mold the foamed styrene thermoplastic elastomer composition (foamed surface material). The foamed surface layer material formed by the method has an extremely low expansion ratio, and it is not possible to develop a composite molded article having a soft feeling as the foamed material of the present invention has.

(4) Cooling By the above-mentioned method, an automobile interior part made of a composite molded body in which the surface layer is foamed and integrated with the base material is held in the mold for a certain period of time and then gradually cooled. Is performed, the temperature is cooled to about room temperature, and the mold is released. Further, in the molding method of the composite molded article, the foamed molded article obtained mainly from two layers has been described, but the composite molded article of the present invention can be obtained in any of two-layered or multi-layered molded articles. it can. Further, the multilayer molded article can be obtained by either a combination of a foamed layer and a foamed layer or a combination of a foamed layer and a non-foamed layer.

[III] Manufacturing Apparatus for Automotive Interior Parts Composed of Composite Molded Article As a foamable multi-layer injection molding apparatus for manufacturing an automotive interior part composed of the composite molded article, injection molding,
After inserting the molded product shaped by press molding or the like into the mold, full-shot the expandable styrene-based thermoplastic elastomer composition (surface layer material) in the gap between the molded product and the mold, Next, using one of the insert injection molding machine capable of moving the movable plate of the mold or the injection molding machine or two or more injection molding machines, when one is injection molded, the mold or the injection molding machine Device 1 capable of moving the movable plate, or a device capable of moving the movable plate when a surface layer material is injected by a multicolor molding machine in which a mold rotates and moves. Can be mentioned.

[IV] Automotive Interior Parts Composed of Composite Molded Products Automotive interior parts composed of the thus obtained composite molded products are automotive interior parts because a thermoplastic resin is used as a base material. From the specific styrene-based thermoplastic elastomer composition having the necessary rigidity and strength, a foaming ratio of 1.5 to 4, a uniform cell diameter, and a skin portion formed on its surface. Since it is formed by being covered with the following foam, it has an excellent appearance as well as an excellent soft feel, and since it has a high-grade feeling, it is an extremely excellent automobile interior part. Further, in order to further improve the surface of the surface layer material, it is possible to apply it as an effective means.

[0030]

EXAMPLES In order to describe the method for producing an automobile interior part made of the composite molded article of the present invention in more detail, the examples and comparative examples of the present invention will be specifically described below. The raw materials and evaluation methods used in the examples and comparative examples are as follows. [I] Raw materials (1) Styrene-based thermoplastic elastomer component TPS-1: Hydrogenated product of styrene / butadiene block copolymer [styrene / ethylene / butylene / styrene copolymer “SEBS” (average molecular weight 85,700, Styrene content 29%)]: 27 wt% Paraffinic oil (average molecular weight 746, ring analysis 0%): 33 wt% Flexural modulus of elasticity according to JIS-K7203 is 10,100 kg / cm ² , and MFR (230 ° C). , 2.16 kg) for 1.5 g / 10 minutes ethylene / propylene block copolymer: 20% by weight, density 0.919 g / cm ³ , and MFR (190 ° C., 2.16 kg) for 4 g / 10 minutes. Low-density polyethylene: A composition consisting of 20% by weight and having a JIS-A hardness of 80.

TPS-2: Hydrogenated product of styrene / butadiene block copolymer [styrene / ethylene / butylene / styrene copolymer “SEBS” (average molecular weight 85,700, styrene content 29%)]: 24. 75% by weight Hydrogenated styrene / isoprene block copolymer [styrene / ethylene / propylene / styrene copolymer "SEPS" (average molecular weight 125,000, styrene content 13%)]: 15% by weight paraffinic oil (Average molecular weight 746, ring analysis 0%): 30.25 weight% Bending elastic modulus according to JIS-K7203 is 9,500 kg / cm ² , and MFR (230 ° C, 2.16 kg) is 15 g / 10 min ethylene. -Propylene block copolymer: 7.5% by weight Flexural modulus according to JIS-K7203 is 10,100 kg / Cm ² , and MFR (230 ° C, 2.16 kg) of 1.5 g / 10 min ethylene-propylene block copolymer: 15% by weight, density 0.919 g / cm ³ , and MFR (190 ° C) , 2.16 kg) is a low-density polyethylene of 4 g / 10 min: 7.5% by weight, and has a JIS-A hardness of 72.

TPS-3: Hydrogenated product of styrene / butadiene block copolymer [styrene / ethylene / butylene / styrene copolymer “SEBS” (average molecular weight 85,700, styrene content 29%)]: 27% by weight % Paraffinic oil (average molecular weight 746, ring analysis 0%): 33% by weight Bending elastic modulus according to JIS-K7203 is 10,100 kg / cm ² , and MFR (230 ° C., 2.16 kg) is 1.5 g / 10 minutes ethylene / propylene block copolymer: 40% by weight, having a JIS-A hardness of 89.

TPS-4: Hydrogenated product of styrene / butadiene block copolymer [styrene / ethylene / butylene / styrene copolymer “SEBS” (average molecular weight 85,700, styrene content 29%)]: 22. 5% by weight hydrogenated styrene / isoprene block copolymer [styrene / ethylene / propylene / styrene copolymer "SEPS" (average molecular weight 125,000, styrene content 13%)]: 10% by weight paraffinic oil ( Average molecular weight 746, ring analysis 0%): 27.5% by weight Bending elastic modulus according to JIS-K7203 is 9,500 kg / cm ² , and MFR (230 ° C, 2.16 kg) is 15 g / 10 min ethylene propylene. Block copolymer: 10% by weight Flexural modulus according to JIS-K7203 is 10,100 kg / cm ² , and an ethylene / propylene block copolymer having an MFR (230 ° C., 2.16 kg) of 1.5 g / 10 min: 10% by weight, a density of 0.919 g / cm ³ , and an MFR (190 ° C., 2 0.16 kg) is a low density polyethylene of 4 g / 10 min: 20% by weight, and has a JIS-A hardness of 86.

TPS-5: Hydrogenated product of styrene / butadiene block copolymer [styrene / ethylene / butylene / styrene copolymer “SEBS” (average molecular weight 246,000, styrene content 33%)]: 33.75 Weight% Paraffin oil (average molecular weight 746, ring analysis 0%): 41.25 weight% Flexural modulus according to JIS-K7203 is 4,300 kg / cm ² , and MFR (230 ° C, 2.16 kg) 6 g / 10 min ethylene / propylene block copolymer: 25% by weight, having a JIS-A hardness of 59.

TPS-6: Hydrogenated product of styrene / butadiene block copolymer [styrene / ethylene / butylene / styrene copolymer “SEBS” (average molecular weight 85,700, styrene content 29%)]: 40. 5% by weight paraffinic oil (average molecular weight 746, ring analysis 0%): 49.5% by weight Bending elastic modulus according to JIS-K7203 is 4,300 kg / cm ² , and MFR (230 ° C, 2.16 kg) is 6 g. / 10 minutes ethylene / propylene block copolymer: 10% by weight, having a JIS-A hardness of 33.

TPS-7: Hydrogenated product of styrene / butadiene block copolymer [styrene / ethylene / butylene / styrene copolymer “SEBS” (average molecular weight 85,700, styrene content 29%)]: 22. 5 wt% paraffinic oil (average molecular weight 746, ring analysis 0%): 27.5 wt% Flexural modulus according to JIS-K7203 is 10,100 kg / cm ² , and MFR (230 ° C, 2.16 kg) 1.5 g / 10 min ethylene / propylene block copolymer: 50% by weight, having a JIS-A hardness of 98.

TPS-8: Hydrogenated product of styrene / butadiene block copolymer [styrene / ethylene / butylene / styrene copolymer “SEBS” (average molecular weight 85,700, styrene content 29%)]: 31. 5 wt% paraffinic oil (average molecular weight 746, ring analysis 0%): 38.5 wt% Flexural modulus according to JIS-K7203 is 4,300 kg / cm ² , and MFR (230 ° C, 2.16 kg) is 6 g. / 10 minutes ethylene / propylene block copolymer: 30% by weight, having a JIS-A hardness of 70.

TPS-9: Hydrogenated product of styrene / butadiene block copolymer [styrene / ethylene / butylene / styrene copolymer “SEBS” (average molecular weight 85,700, styrene content 29%)]: 31. 5 wt% paraffinic oil (average molecular weight 746, ring analysis 0%): 38.5 wt% Flexural modulus according to JIS-K7203 is 4,300 kg / cm ² , and MFR (230 ° C, 2.16 kg) is 6 g. / 10 min ethylene-propylene block copolymer: 20 wt% density 0.919 g / cm ³ and MFR (190 ° C., 2.16 kg) 4 g / 10 min low density polyethylene: 10 wt% A composition having a JIS-A hardness of 71.

TPS-10: Hydrogenated product of styrene / butadiene block copolymer [styrene / ethylene / butylene / styrene copolymer “SEBS” (average molecular weight 85,700, styrene content 29%)]: 31. 5 wt% paraffinic oil (average molecular weight 746, ring analysis 0%): 38.5 wt% Flexural modulus according to JIS-K7203 is 4,300 kg / cm ² , and MFR (230 ° C, 2.16 kg) is 6 g. / 10 min ethylene / propylene block copolymer: 10 wt% density 0.919 g / cm ³ and MFR (190 ° C, 2.16 kg) 4 g / 10 min low density polyethylene: 20 wt% A composition having a JIS-A hardness of 66.

[0040] (2) a blowing agent component foaming agent -1: foaming agent master batch mixture containing 20 wt% of an inorganic salt and an organic acid (Mitsubishi Petrochemical Co., Ltd., "Fine blow S20N") blowing agent-2 : A blowing agent masterbatch containing 20% by weight of azodicarboxylic acid amide (“FineBlow MX87” manufactured by Mitsubishi Petrochemical Co., Ltd.)

[II] Evaluation Method (1) Measurement of Melt Tension and Melt Spreadability The melt tension was measured by using a melt tension tester type II (manufactured by Toyo Seiki Seisakusho) with a length of 8.000 mm.
From a die with an inner diameter of 2.095 mm and an outer diameter of 9.50, 190
The melt tension (abbreviated as MT) is defined as the tension when the molten resin extruded at a temperature of ° C at an extrusion rate of 1 cm / min is drawn into a filament at a take-up rate of 4 m / min. In the measurement of the melt spreadability, the draw speed is increased at a rate of 120 m / min per minute, and the draw speed when the filament is cut is defined as the melt spreadability. The above measurement was carried out on a composition containing a compound other than the foaming agent.

(2) Measurement of Foaming Ratio Foaming was obtained by dividing the specific gravity of the non-foamed product by the specific gravity of the foamed product obtained from the volume and weight of the foamed product when the cavity of the mold was expanded and foamed. Magnification (times) was used.

(3) Measurement of Cell Structure The produced composite was cut and the cross section of the surface layer foam was visually observed. As a result, those having a uniform fine cell structure were evaluated as good, and those having a hollow layer in which the cells were destroyed and cases where there were bubbles having a diameter of 2 mm or more were considered as poor.

(4) Judgment of appearance of foam The surface smoothness (dents, sink marks) and swirl marks of the composite were observed. Those that could fit automobile interior parts were judged to be good, and those that could not fit were judged to be unsuitable.

(5) Feeling The surface of the composite body is pressed with a finger, and the 1991 model "Corolla 1500
Those having a soft feeling similar to those of the instrument panel mounted on "SE-L" were judged to be good, and those which were hard or soft and bottomed on the substrate were judged to be unsuitable.

[III] Experimental Examples Examples 1 to 4 and Comparative Examples 1 to 6 Using a G650-A-FM type injection molding machine manufactured by Kobe Steel, Ltd., a length of 500 mm, a width of 250 mm and an average wall thickness of Two
The composite polypropylene resin was injection-molded as a raw material of a base material using a mold for obtaining an automobile interior part having a size of mm. Next, the composite polypropylene resin base material is mounted in a mold for obtaining an automobile interior part having an average wall thickness of 4 mm, and the foamable styrene-based thermoplastic elastomer composition is injected at a molding temperature of 200 ° C. Pressure 700kg / cm ²
After making a full shot in the fixed mold 38 ° C and movable mold 45 ° C mold cavities, open the movable plate 3.5 mm at a speed of 5 mm / sec to expand the mold cavity volume and foam. At the same time, it was integrated with the base material by heat fusion, and after sufficiently cooled, it was taken out from the mold. Two-layer injection molding was continuously performed for 15 shots by the above method,
Two-layer injection molded products of 0 to 15 shots were evaluated, and the results are shown in Tables 1 and 2. Further, Tables 1 and 2 show that the composition (however, before blending the foaming agent) has a melt tension, a melt spreadability,
The JIS-A hardness is also shown.

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

The method for producing an automobile interior part made of such a composite molded article has the rigidity and strength required for an automobile interior part because a thermoplastic resin is used as a base material. Together with the excellent soft feeling, since it is formed by being uniformly foamed, foamed with a skin portion formed on the surface thereof, and covered with a foam made of a specific styrene-based thermoplastic elastomer composition. In addition, the hardness is high, the appearance is good, and the product has a high-class feeling, so that it is possible to manufacture extremely excellent automobile interior parts.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location B29L 31:58 (72) Inventor Izumi Iwai 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Petrochemical Co., Ltd. Company Yokkaichi Research Institute (72) Inventor Masayoshi Ueda 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Naoki Murase 1 Toyota Town, Toyota City, Aichi Toyota Motor Corporation (72) Inventor Keiichi Hasegawa 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (72) Inventor Hiroaki Kondo 2-3-3 Niihama, Arai Town, Takasago City, Hyogo Prefecture Kobe Steel Works Takasago Co., Ltd. Inside the Works (72) Inventor Masahiko Kashiwa 2-3-1, Niihama, Arai Town, Takasago City, Hyogo Prefecture Kobe Steel Works Takasago Works

Claims (1)

[Claims] 1. A thermoplastic resin is injection-molded into a void portion in a mold in which a separately molded thermoplastic resin molded product is mounted, or after the thermoplastic resin is injection-molded, the internal volume of the mold is increased. Based on the hydrogenated product of (a) styrene / conjugated diene block copolymer, the melt tension at 190 ° C was 1.5 g or more, and the melt ductility was 100 m in the void portion in the provided mold.
/ Min or more and JIS-A according to JIS-K6301
100 parts by weight of a styrene-based thermoplastic elastomer component having a hardness of 30 to 95, and (b) a foaming agent component
After injecting 0.5 to 10 parts by weight of the expandable styrene-based thermoplastic elastomer composition, the internal volume of the mold is expanded to foam and integrate the expandable styrene-based thermoplastic elastomer composition. A method for manufacturing an automobile interior part comprising a composite molded article, comprising: