JP2003039448A - Method for producing molded article with foam layer and foamable hot melt resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently producing a car trim article comprising a skin, a foamed layer, and a base material. SOLUTION: When a molding with the foamed layer in which the skin, the foamed layer, and the base material are molded integrally, the base material and the skin, which are molded in prescribed shapes respectively, are adhered to a mold, a void for forming the foamed layer is formed between the base material and the skin, and the void is filled with a foamed hot melt resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a molded product with a foam layer used for automobile interiors, a foam layer forming material, and a foamable hot melt resin composition which functions as an adhesive between a skin and a substrate. Is.

[0002]

2. Description of the Related Art Instrument panels, door trims,
Molded products with foam layers are used for automobile interior parts such as armrests, console boxes, pillars, and ceilings. The conventional method for producing a molded article with a foam layer utilizes the slush foaming method, in which a powdered thermoplastic elastomer is sprinkled thinly in a preheated mold to produce a slush skin, and then a powdered thermoplastic elastomer. A mixture of a heat-decomposable foaming agent and a foaming agent is adhered to the slush skin to form a foam layer, and at the same time, the slush skin and the foam layer are fused. Next, the slush skin with the foam layer is cooled and then released from the mold, and is bonded to the base material previously molded by injection molding or vacuum molding with an adhesive to obtain a molded product with the foam layer.

Japanese Unexamined Patent Publication No. 2000-263647 discloses a method for producing a molded article with a foam layer. In this method, a hot melt adhesive is used as a material for adhering a base material and a skin with a foam layer. However, the foam layer is not formed by a hot melt adhesive.

Japanese Unexamined Patent Publication (Kokai) No. 9-208928 discloses a sealing agent composition composed of a synthetic rubber resin, a tackifier, a wax and a liquid hydrocarbon plasticizer. The purpose of this is to prevent the urethane resin foam from leaking during the production of, and not to form a foam layer.

[0005]

Under the importance of protecting the global environment, it has been desired to develop a molded product with a foam layer composed of a recyclable polyolefin material. However, since the polyolefin resin is flexible, it is difficult to powder it, and the powder processing cost is high. Therefore, if the conventional slush foaming method is applied, the manufacturing cost of a molded product with a foam layer made of a polyolefin resin increases, and thus it is difficult to apply the method.

The present invention has been made in view of the above-mentioned problems, and has an excellent expansion ratio, foam-controlling property, heat resistance, and flexibility made of a polyolefin-based resin without powdering the polyolefin-based resin. It enables the production of molded products with a foam layer, and simultaneously enables the formation of a foam layer and three-layer adhesion consisting of a skin, a foam layer, and a base material. The purpose is to reduce the manufacturing cost of the product and to save labor by three-layer adhesion of a polyolefin-based material, which is called a difficult-to-bond material.

[0007]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that a specific foamable hot melt resin is used as a foam layer forming material to set a base material with an outer skin. The present invention has been completed by finding that a specific manufacturing method of pouring into a metal mold and foaming is useful for manufacturing a molded article with a foam layer. That is, the first aspect of the present invention is to manufacture a molded article with a foam layer in which a skin, a foam layer, and a base material are integrally molded, by bringing the base material and the skin, each having a predetermined shape, into close contact with a mold. A method for producing a molded product with a foam layer, comprising providing a space for forming a foam layer between the base material and the skin, and then filling the space with a foamed hot melt resin. Is a method for producing a molded article with a foam layer, wherein the hot melt resin in the first invention is a foamable hot melt resin mixed with an inert gas, and the third invention is a foamable hot melt. Foaming characterized in that the resin contains 100 parts by weight of a synthetic rubber resin, 0 to 500 parts by weight of a tackifier, 0 to 300 parts by weight of a wax, and 30 to 300 parts by weight of a liquid hydrocarbon plasticizer. Manufacture of molded products with layers A fourth invention is a method for producing a molded article with a foam layer, wherein the skin, the foam layer and the base material are olefin resin materials or composite olefin resin materials, and the fifth invention is The first to fourth inventions characterized in that it contains 100 parts by weight of a synthetic rubber resin, 0 to 500 parts by weight of a tackifier, 0 to 300 parts by weight of a wax, and 30 to 300 parts by weight of a liquid hydrocarbon plasticizer. It is a foamable hot melt resin composition used in the method for producing a molded article with a foam layer of the invention. Hereinafter, the present invention will be described in detail.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The skin used in the present invention is manufactured by a powder slush molding method, a vacuum molding method, or the like. In the powder slush molding method, a thermoplastic resin powder is put in a box, and a heated mold is covered so as to cover the box. When the box is turned over, the resin powder contacting the mold is melted and adheres to the mold in a sheet shape, and the grain pattern on the surface of the mold is transferred to the sheet. Here, the box is turned over again and returned to the original position, the lid is opened, and the sheet-shaped molded product attached to the mold is peeled off to obtain a skin. The vacuum molding method is a method in which a thermoplastic sheet is heated and set in a mold, and then vacuum drawing is performed to bring it into close contact with the mold, thereby transferring the grain pattern on the surface of the mold to the sheet.

The material of the skin used in the present invention is
An olefin-based thermoplastic elastomer, a styrene-based thermoplastic elastomer, a urethane-based thermoplastic elastomer, or a polyester-based thermoplastic elastomer can be preferably used. A more preferable material for recycling is an olefinic thermoplastic elastomer. Further, the thickness of the skin is preferably 0.5 mm to 2 mm.

As the material of the base material used in the present invention, olefin type thermoplastic elastomer, styrene type thermoplastic elastomer, urethane type thermoplastic elastomer, polyester type thermoplastic elastomer or the like can be preferably used. A more preferable material for recycling is an olefinic thermoplastic elastomer. The base material is plate-shaped, and its thickness is preferably 1.5 mm to 3 mm.

The expandable hot-melt resin used in the present invention fills the space between the skin and the base material to form a foam layer, and integrates the skin and the base material, and is discharged from a nozzle. It has the property of foaming. The preferred foamable hot melt resin in the second invention is a hot melt hot melt mixed with an inert gas by mechanical mixing, and when the melt is discharged from the nozzle into the space between the skin and the substrate. The resulting pressure reduction in the melt causes the microbubbles in the melt to foam. Preferred inert gases are air, nitrogen, carbon dioxide, etc.,
The preferable content ratio of the inert gas may be appropriately adjusted according to the characteristics of the melt and the characteristics of the target molded article. Preferred main components in the hot melt resin are polyolefin-based, elastomer-based, polyester-based, EVA-based,
Polyamide-based and elastomer-based hot melt resins are particularly preferable because they are polyamide-based, have good recycling properties, and have good adhesiveness to olefin-based materials.

The preferred foamable hot-melt resin in the third invention is mainly composed of an elastomer, and 100 parts by weight of a synthetic rubber resin, 0 to 500 parts by weight of a tackifier, 0 to 300 parts by weight of a wax and a liquid form. It contains 30 to 300 parts by weight of a hydrocarbon plasticizer. The details will be described below.

The synthetic rubber resin used in the third invention is a styrene-diene block copolymer such as a styrene-isoprene block copolymer and a styrene-butadiene block copolymer, or a hydrogenated product thereof. SEBS (styrene-ethylene-butylene-
Styrene) block copolymer and SEPS (styrene-
(Ethylene-propylene-styrene) block copolymer
(Hereinafter, the styrene-diene-based block copolymers and hydrogenated products thereof are collectively referred to as rubber-based resin A), ethylene-propylene rubber and butyl-based rubber (hereinafter collectively referred to as rubber-based resin B). , And they can be used alone or in combination of two or more. Preferred for the present invention are SEBS-based block copolymers and SEPS-based block copolymers having excellent heat resistance, and a resin mixture comprising the above rubber-based resin A and rubber-based resin B is preferred. Rubber type resin A and rubber type resin B
As a compounding ratio when used together, rubber-based resin A20-8
A rubber resin B of 80 to 20% by weight is suitable at 0% by weight. When the amount of the rubber-based resin A is less than 20% by weight, heat resistance cannot be satisfied, while when the amount of the rubber-based resin B is less than 20% by weight, it becomes difficult to obtain flexibility.

Specific examples of the styrene-isoprene block copolymer used in the present invention include Califlex TR-1107 (trade name), Califlex TR-1111 (trade name), and Cali, manufactured by Shell Chemical Co., Ltd. Flex TR-1112 (trade name) and Califlex TR-
1117 (trade name) and the like. Also, styrene-
Examples of butadiene-based block copolymers include Califlex TR-1101 (trade name) and Califlex TR-1102 (trade name) manufactured by the same company. S
Examples of EBS-based block copolymers include Kraton G-1650 (trade name), Kraton G-1652 (trade name), Kraton G-1657 (trade name), and Kraton G-1726 (trade name) manufactured by Shell Chemical Co., Ltd. ), And further specific examples of the SEPS-based block copolymer include Septon 2002 (trade name), Septon 2003 (trade name), and Septon 2043 (trade name) manufactured by Kuraray Co., Ltd.

The ethylene-propylene rubber preferably used in the present invention is a copolymer of ethylene and propylene, or 1,4-hexadiene, dicyclopentadiene, ethylidene norbornene and the like are introduced in a small amount as a third component. Examples of commercially available products include ethylene propylene rubber EP-11, ethylene propylene rubber EP-43, and ethylene propylene rubber E manufactured by Nippon Synthetic Rubber Co., Ltd.
P-82 or the like can be used. Examples of the butyl rubber used in the present invention include those obtained by copolymerizing isobutylene with several% of isoprene, or halides thereof. Examples of commercially available products include Butyl Rubber 065 and Butyl Rubber 268 manufactured by Japan Synthetic Rubber Co., Ltd.

Preferred tackifiers used in the third invention include rosin type, terpene type and petroleum resin type. Examples of the rosin system include natural rosin, polymerized rosin and derivatives thereof (modified rosin and its water additive, methanol ester, glycerin ester, pentaerythritol ester and their water additives) and the like. As commercially available products, gum rosin, wood rosin, ester gum A, ester gum H, pen cell A, pen cell C (above, manufactured by Arakawa Chemical Industry Co., Ltd.), FORAL 85, FORAL 10
5, Hentalin C (above, manufactured by Hercules Co., Ltd.) and the like. Examples of the terpene-based resin include polyterpene-based resin, terpene-phenolic resin and hydrogenated products thereof. Commercially available products thereof include YS resin A-
115, YS Resin To-105, YS Polystar T-
115, YS Polystar 2130, Clearon P-11
5, Clearon M-125 (above, manufactured by Yasuhara Chemical Co., Ltd.) and the like. In the petroleum resin system, aromatic petroleum resin composed of styrene, α-methylstyrene, vinyltoluene, indene, methylindene, etc., C
There are aliphatic petroleum resin, cyclopentadiene petroleum resin, aliphatic / aromatic or aliphatic / alicyclic copolymer petroleum resin mainly containing 5 fractions, and hydrogenated petroleum resin obtained by hydrogenating these. As commercially available products, Escorets 2101 (manufactured by Tonex Co., Ltd.), Quinton C-100 (manufactured by Nippon Zeon Co., Ltd.), Alcon P-90, Alcon P-1
15, Alcon M-100 (above, manufactured by Arakawa Chemical Industry Co., Ltd.), Pico Pale 110SF (made by Pico), Wing Tack 95, Wing Tack 115 (above, Goodyear), Petrosin # 100, Petrosin # 120 (above,
Mitsui Petrochemical Industry Co., Ltd.), Marukalets H-80
0, Marukalets H-790 (above, Maruzen Petrochemical Co., Ltd.), and the like.

These tackifiers are used for increasing the adhesiveness to the adherend, and those preferable for the present invention are petroleum resin type and hydrogenated petroleum resin. In order to maintain the balance of the compatibility, thermal stability, color tone, cohesive strength and the like of the water-soluble hot melt resin composition, it is also preferable to use not only one of the above tackifiers but also a combination of two or more thereof. The compounding amount of the tackifier is 0 part by weight or more and 500 parts by weight or less based on 100 parts by weight of the rubber-based resin. More preferably 0
˜300 parts by weight. If it exceeds 500 parts by weight, the cohesive force of the adhesive decreases, and as a result, the adhesive force and heat resistance decrease, making it difficult to achieve the object of the present invention.

The wax used in the third invention is as follows.
Examples include paraffin wax, microwax, low molecular weight polyethylene, low molecular weight polypropylene, and amorphous polyalphaolefin. Paraffin wax is generally a solid hydrocarbon separated from a high boiling fraction of crude oil, and microwax is a high melting point wax generally purified from a high boiling fraction of crude oil, both of which are, for example, Nippon Oil Co., Ltd. It is commercially available from Wax Co., Ltd. The low molecular weight polyethylene is a wax having a softening point of usually 80 ° C. or higher and 150 ° C. or lower, which is generally obtained by oxidative decomposition of a low polymer of ethylene or polyethylene, and examples thereof include Neowax L (Yasuhara Chemical Co., Ltd.) and Sunwax 151 as commercially available products. -P, Sun Wax E-300 (above, Sanyo Chemical Industry Co., Ltd.), ACPE-617, A
CPE-629 (above, Allied Chemical Co., Ltd.), Hoechst wax PE520 (Hoechst Co., Ltd.) and the like can be mentioned. Low molecular weight polypropylene is generally a low polymer of propylene,
It is an oxidative decomposition product of polypropylene or atactic polypropylene, and is VISCOL 550P, VISCOL 660P (above, Sanyo Chemical Industry Co., Ltd.), Hoechst wax PP (Hoechst Co.), Vistax L (Chiba Fine Chemical Co., Ltd.), Sun Attack ( Asahi Gosei Chemical Co., Ltd.) and the like are listed as commercial products. Amorphous polyalphaolefin is a low molecular weight amorphous polymer obtained by copolymerizing propylene with ethylene, butene-1, etc., and commercially available products such as LEXTACK 2215 and LEXTACK 2115 (above, Ube Lexen Co., Ltd.) Can be mentioned. It is also possible to use a product obtained by copolymerizing the above hydrocarbon wax with maleic acid, vinyl acetate, acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester or the like with ethylene, etc. The one on the market is used.

These waxes are used for the purpose of increasing the fluidity and non-tackiness of the foamable hot melt resin during heating and melting, improving the cohesive force at room temperature and adjusting the heat softening point. The compounding amount is 0 part by weight or more and 300 parts by weight or less, and more preferably 0 part by weight or more and 200 parts by weight or less, with respect to 100 parts by weight of the rubber-based resin.
When it exceeds the weight part, the flexibility of the foamable hot melt resin is deteriorated, and cold resistance and impact resistance are lost.

The liquid hydrocarbon plasticizer used in the third invention is a petroleum high boiling fraction of paraffin type, naphthene type, aromatic hydrocarbon type, which is generally referred to as synthetic rubber extender oil or process oil. And liquid resins such as liquid rosin and liquid terpene and polybutene, polyisobutylene,
Examples include liquid hydrocarbon synthetic rubbers such as polyisoprene, polybutadiene and hydrogenated products thereof, and commercially available process oils such as Shelf Rex (Shell Chemical Co., Ltd.), Diana Process Oil (Idemitsu Kosan Co., Ltd.), and Dimalon. , YS oil (Yasuhara Chemical Co., Ltd.), liquid paraffin, etc., and liquid hydrocarbon synthetic rubbers such as Klaprene LIR (Kuraray Co., Ltd.), Idemitsu Polybutene (Idemitsu Petrochemical Co., Ltd.), Nisseki Polybutene.
(Nippon Petrochemical Co., Ltd.) and the like.

These liquid hydrocarbon type plasticizers are used for the flexibility of the foamable hot melt resin, the adhesion to the insert, the decrease of the melt viscosity and the improvement of the fluidity at the time of melt coating. Is 30 to 300 parts by weight, more preferably 50 parts by weight or more and 250 parts by weight or less, 30
If it exceeds 0 parts by weight, the cohesive force of the expandable hot melt resin composition is lowered, and the heat resistance is impaired.

Further, a filler, an antiaging agent, an ultraviolet ray inhibitor and the like can be used as an additive in the foamable hot melt resin composition of the present invention. Examples of the filler include talc, silica, calcium carbonate and carbon. Black, zinc white, titanium oxide, inorganic pigments, etc. are included, respectively, to prevent dripping during melt coating and improve yarn breakage, improve thermal stability of the foamable hot melt resin composition in a heated and melted state, and thixotropic It is used according to the purpose for giving, coloring, etc. The anti-aging agent is added within the range of 3% by weight to the whole composition for the purpose of protecting against thermal oxidation during heating and melting, and the ultraviolet ray preventing agent against ozone and ultraviolet rays.

The expandable hot melt resin composition of the present invention is obtained by the above-mentioned constitution.
Considering the appropriate viscosity of the melt-foaming device, the melt viscosity of the foamable hot-melt resin is 1.0 at 150 to 200 ° C.
It is preferably in the range of 0 to 70,000 mPa · s,
More preferably, it is 1,000 to 50,000 mPa · s.
The softening point (R & B type) of the foamable hot melt resin composition is preferably 80 ° C. or higher. When the temperature is lower than 80 ° C., when exposed to a high temperature environment, the adhesive force between the foam layer and the skin or the base material is reduced, and delamination may occur.

The foamable hot melt resin composition in the present invention is preferably usually 140 ° C. or higher and 250 or higher under a nitrogen stream.
A method of dissolving or mixing each component simultaneously or sequentially by rotating a stirring blade in a melting tank called a heating type melting and stirring tank at a temperature of ℃ or below, and simultaneously heating each component by twin-rotating blades called a kneader to simultaneously mix each component. Alternatively, it can be produced by a known method used in the production of ordinary hot melt adhesives, such as a method of sequentially adding and kneading, or a method of melting and mixing under heating with a single-screw or twin-screw screw in an extruder.

[0025]

EXAMPLES The present invention will be specifically described below based on Examples and Comparative Examples. FIG. 1 is a cross-sectional view showing the structure of a molded article with a foam layer for an automobile interior article according to an embodiment of the present invention. The molded product with a foam layer comprises a skin 1, a foamable hot-melt resin foam layer 2, and a base material 3.

The manufacturing method of the molded product with the foam layer shown in FIG. 1 will be explained. As shown in the mold sectional view of FIG. 2, the outer skin 1 is set on the lower mold 4 and the base material 3 is set on it. After accurately covering the upper mold 5 and firmly fixing it, a pressurized solution formed by mechanically mixing and melting a pressurized gas with a hot melt hot melt by a foam melt applicator 6 is used to form a pressurized solution with the skin 1. It is injected into the gap of the material 3 and simultaneously the foaming and the adhesion of the skin and the base material are performed. The applicator used at this time is FM-150 manufactured by Nordson Corporation.

The evaluation method of the molded article with the foam layer and the foamable hot melt resin composition obtained in each example was carried out by the following methods. Foaming ratio of the molded product with a foam layer: Determined from the specific gravity of the foam layer and the specific gravity of the hot melt resin. Elasticity of molded article with foam layer: The skin side was pressed with a finger, and it was judged by touching with a finger whether or not the elasticity was suitable. Adhesion state of the molded product with the foam layer: Good when the formed molded product with the foam layer had no interlayer peeling. Melt viscosity of foamable homelt: Measured with a B-type rotational viscometer by heating to 190 ° C. according to JIS-K-2862. R & B Softening Point of Foaming Homelt: JIS-K-2863
The measurement was performed according to (Softening point test method for hot melt adhesives).

The foamable hot melt resin composition of Example 1 was prepared by adding 0.5 kg of Kraton G-1652, 0.5 kg of ethylene propylene rubber and Alcon P-115 to a 10 L kneader heated to 200 ° C. under a nitrogen stream. 1 kg and 50 g of Irganox 1010 were added and melt mixed for about 30 minutes. Next, 0.5kg of Sun Attack and 6 of Viscole
An additional 0.5 kg of 60P was added and melt-mixed for about 30 minutes. After confirming that they were sufficiently mixed, 1 kg of YS Polystar 2130 and 0.8 kg of Idemitsu Polybutene 2000H were further added. The mixture was melt-mixed for 1 hour, degassed under reduced pressure at 200 ° C. for about 30 minutes, and then extracted. The evaluation results by the above-described evaluation method are shown in Table 1 as Example 1 together with the blending composition. Examples 2-5 were similarly prepared and evaluated. In each of Examples 1 to 5, good performance was obtained.

[0029]

[Table 1]

The details of the compounding ingredients in Table 1 are as follows.・ Clayton G-1652 (Shell Chemical Co., Ltd.): SEBS block copolymer synthetic rubber resin ・ Ethylene propylene rubber EP-11 (Nippon Synthetic Rubber Co., Ltd.): Ethylene propylene rubber synthetic rubber resin・ Arcon P-115 (manufactured by Arakawa Chemical Co., Ltd.): Tackifier made of hydrogenated petroleum resin ・ YS Polystar 2130 (manufactured by Yasuhara Chemical Co., Ltd.):
Tackifier made of terpene phenolic resin, Sun Attack (manufactured by Asahi Gosei Chemical Co., Ltd.): Wax made of atactic polypropylene, Viscole 660P (manufactured by Sanyo Kasei Co., Ltd.): Wax made of low molecular weight polypropylene, Idemitsu Polybutene 2000H ( Idemitsu Petrochemical Co., Ltd.): Liquid hydrocarbon plasticizer made of liquid hydrocarbon synthetic rubber, Diana Process Oil PW-380 (made by Idemitsu Kosan Co., Ltd.): Liquid hydrocarbon plasticizer made of process oil, Irganox 1010 (Ciba Geigy Co., Ltd.): Antioxidant

[0031]

EFFECTS OF THE INVENTION According to the present invention, a composite molded article composed of a skin, a foam layer and a substrate can be efficiently produced.
According to the present invention, it is possible to produce a molded product with a foam layer having an excellent expansion ratio, foam control property, heat resistance, and flexibility without using an expensive powder-processed resin for forming the foam layer. At the same time as forming the foamed layer, it is possible to achieve three-layer adhesion consisting of a skin, a foamed layer, and a base material. Further, the present invention can also be applied to the production of a molded product with a foam layer made of a polyolefin resin having excellent recyclability, and can reduce the manufacturing cost of a molded product with a foam layer composed of a polyolefin material. By providing good three-layer adhesion of polyolefin-based materials, which are said to be difficult to adhere to, it is possible to provide molded products with high adhesion reliability and save manufacturing labor.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the structure of a molded product with a foam layer obtained according to the present invention.

FIG. 2 is a cross-sectional view of the inside of a mold showing the arrangement of a skin and a base material according to the present invention.

[Explanation of symbols]

1 epidermis 2 foam layer 3 base materials 4 epidermis 5 Space for foam layer formation 6 base material 7 Lower mold 8 Upper mold 9 Foam melt applicator

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Makoto Imahori             1 East of Funami-cho, Minato-ku, Nagoya City, Aichi Prefecture             Inside Agosei Co., Ltd. F-term (reference) 4F204 AA03 AA45 AB01 AB02 AB07                       EA01 EB01 EB11 EB13 EF01                       EF05 EF27 EF37 EL02

Claims (5)

[Claims] 1. When manufacturing a molded article with a foam layer in which a skin, a foam layer and a base material are integrally molded, a base material and a skin, each of which has a predetermined shape, are brought into close contact with a mold to form a base material. A method for producing a molded article with a foamed layer, comprising providing a void for forming a foamed layer between skins, and then filling the void with a foamed hot melt resin. 2. The method for producing a molded article with a foam layer according to claim 1, wherein the hot melt resin is a foamable hot melt resin mixed with an inert gas. 3. The hot melt resin is a synthetic rubber resin 10.
0 parts by weight, tackifier 0-500 parts by weight, wax 0-
The method for producing a molded article with a foam layer according to claim 1, which comprises 300 parts by weight and 30 to 300 parts by weight of a liquid hydrocarbon plasticizer. 4. The method for producing a molded article with a foam layer according to claim 1, wherein the skin, the foam layer and the base material are an olefin resin material or a composite olefin resin material. 5. A composition containing 100 parts by weight of a synthetic rubber resin, 0 to 500 parts by weight of a tackifier, 0 to 300 parts by weight of a wax and 30 to 300 parts by weight of a liquid hydrocarbon plasticizer. A foamable hot melt resin composition used in the method for producing a molded article with a foam layer according to any one of 1 to 4.