JPH08238701A - Cover skin material - Google Patents

Abstract

PURPOSE: To bond sufficiently a cover skin and a base resin, even if the base resin used is of such a type as is apt to flow easily by performing a base resin molding process and a cover skin and base resin bonding process in a single step. CONSTITUTION: A rectangular uneven part 15 is shaped like right-angled isosceles triangles arranged side by side, and is made of TPO (polyolefin thermoplastic elastomer) which is also used for another cover skin structure. When using this cover skin 10, a molten base resin comes into contact with and adheres to only each projecting part. A foam layer 16 which is known to work as a heat insulating layer, ensures a positive adhesion between the base resin and the cover skin. An unwoven cloth 17 should be of such a type as to be made of polypropylene, and has numerous unevennesses on the surface of the unwoven cloth 17, so that, in a simultaneous process of molding and adhesion, the quantity of heat dissipated from the base resin through the unwoven cloth is minimized. In addition, the unwoven cloth 17 works also as a heat-insulating layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a skin material for a resin product having at least two members, a skin and a base resin.

[0002]

2. Description of the Related Art Among sheets used for interior materials of vehicles, there is a layered resin product produced by adhering a designed surface skin and a base resin. Generally, in such a resin product, a thermoplastic polyolefin-based elastomer (TPO) is used for the skin and polypropylene (PP) is used for the base resin.

Various methods are conceivable for laminating the base resin and the epidermis. Among them, there is a method of forming the base resin on the epidermis at the same time as molding by low pressure injection or hot stamping. FIG. 2 shows an explanatory view of the manufacturing process.
In the figure, the skin 22 is set on the upper mold 20, and the base resin 23 is set on the lower mold 21. The block-shaped base resin 23 of the lower mold 21 is the one injected from the nozzle and is soft. The temperature of the injected base resin is about 200 to 230 ° C. Its melting point is generally about 120 ° C. The upper and lower molds 20 and 21 are warmed to about 50 to 60 ° C.

When the upper die 20 and the lower die 21 are pressed against each other in this state, the lumpy base resin 23 is rolled and cooled and solidified, so that the base resin can be molded and attached in one step. To be done. The skin may be preliminarily shaped according to its shape and material, or may be formed flat at the same time.

[0005]

In the above-mentioned manufacturing process, if the base resin that does not easily flow is used, satisfactory adhesion between the base resin and the skin can be achieved. The base resin that does not flow easily generates a large amount of heat due to self-friction during the molding process. Since this heat delays the solidification of the base resin at the circumscribed portion, the disadvantage that the base resin is solidified before bonding does not occur. However, the base resin that is difficult to flow is not suitable for fine molding.

On the other hand, if a base resin having a flowable property is used, the base resin can be satisfactorily molded. That is, when the upper and lower molds are pressed against each other and pressed, the easily flowable base resin flows quickly along the mold, so that a uniform molded product having a shape and thickness faithful to the mold can be obtained.

However, since the base resin that flows easily generates almost no frictional heat, it cools quickly and may be solidified before adhering to the skin. In particular, the closer to the periphery of the mold, the incomplete adhesion, and the easier it is to peel from the end.
When either end is peeled off, the peeling gradually progresses from there toward the center. It is possible that the base resin and the epidermis may separate if the use is continued.

An object of the present invention is to provide a method for producing a resin product having a skin and a base resin by performing a molding process of the base resin and a bonding process of the skin and the base resin in one step. The object of the present invention is to provide a base resin capable of sufficiently adhering the skin and the base resin even if the base resin has a property of easily flowing.

[0009]

According to the invention, the above-mentioned object is achieved by the means described in the claims.

That is, the invention of claim 1 is a skin material which is adhered to a base resin in the same step as the molding of the base resin in the manufacturing process of the resin product, and has a concavo-convex pattern on at least one surface. It is a skin material having. The resin product using this skin material has a step of forming a skin having irregularities on the surface on at least one side, and a step of setting the skin on the die A so that the surface having the irregularities faces the die B. , Mold B and mold A that support the molten block-shaped base resin
And a step of pressing and can be manufactured.

Further, the invention of claim 2 is a skin material which is adhered to a base resin in the same step as the molding of the base resin in the manufacturing process of the resin product, and at least one surface of which is heat-insulated. A skin material having layers. A resin product using this skin material has a step of forming a skin having a heat insulating layer on the surface on at least one side, and the skin having the heat insulating layer facing the mold B is set in the mold A. It can be manufactured by including a step and a step of pressing the mold B and the mold A that support the molten block-shaped base resin.

Further, the invention of claim 3 is a skin material which is adhered to the base resin in the same step as the molding of the base resin in the process of manufacturing the resin product, and the non-woven fabric is formed on at least one surface of the skin material. It is a skin material having. The resin product using this skin material has a step of forming a skin having a nonwoven fabric on the surface on at least one side, and a step of setting the skin on the mold A so that the surface having the nonwoven fabric faces the mold B. , And a step of pressing the mold B and the mold A that support the molten block-shaped base resin.

According to a fourth aspect of the present invention, there is provided a skin material which is adhered to the base resin in the same step as the molding of the base resin in the process of manufacturing the resin product, the base material being at least one surface of the skin material. A skin material having an adhesive layer having a lower melting point than the material resin. A resin product using this skin material has a step of forming a skin having an adhesive layer having a melting point lower than that of the base resin on the surface on at least one side, and the surface having the adhesive layer is made to face the mold B. To set the outer skin on the mold A, and the mold B and the mold A that support the molten block-shaped base resin.
And a step of pressing and can be manufactured.

[0014]

According to the first aspect of the invention, the uneven portion is provided on the surface skin. Therefore, when the molding simultaneous application is performed, the base resin flows from the convex portion of the skin to the convex portion and does not contact the concave portion at first, so that the amount of heat taken to the skin is reduced accordingly. Therefore,
Since the molten base resin cools slowly, the adhesive strength increases. Further, the uneven portion also has an effect of generating frictional heat.

According to the second aspect of the present invention, the heat insulating layer is provided on the skin. Therefore, when the simultaneous bonding of molding is performed, the temperature of the contact surface between the base resin and the skin becomes high due to the presence of the heat insulating layer, so that sufficient adhesion between the skin and the base resin is achieved.

According to the third aspect of the invention, a nonwoven fabric is provided on the surface skin. Since the non-woven fabric has irregularities and also functions as a heat insulating layer, it has the effects of the inventions of claims 1 and 2.

According to the invention of claim 4, an adhesive layer having a low melting point is provided on the skin. In the case of simultaneous attachment by molding, once the adhesive layer having a low melting point is melted, the molten state can be maintained even after the base resin is solidified. Therefore, the base resin and the surface skin are firmly adhered to each other due to the presence of the adhesive layer in a molten state even at a location where the cooling progresses quickly and the adhesion between the base resin and the surface skin ends insufficiently.

[0018]

EXAMPLES FIGS. 1 (A) to 1 (D) are sectional views showing an example of a skin material according to the present invention. In the figure, the upper main layers of the respective epidermis 10 to 13 shown in (a) to (d) are made of TPO with a pattern. Also, the sublayers 15-18 on the lower side of the respective epidermis 10-13
The various materials mentioned later are used for this. Epidermis 10-1
Although 3 is usually adhered to a base resin made of PP, it goes without saying that the base resin and the material of the skin can be appropriately selected.

FIG. 1A is an enlarged view of a cross section of a skin having a rectangular rough surface. The rectangular concavo-convex portion 15 has a shape in which isosceles right triangles are lined up, and TPO is used as a material as in other skin structures. This epidermis 10
When the above is used, the molten base resin is brought into contact with and adheres only to each convex portion, so that the base resin and the skin are surely adhered. It should be noted that since this bonding is point bonding instead of surface bonding, the adhesive strength may be reduced, but if a material having a large adhesive strength is used, the adhesive strength can be maintained as it is.

FIG. 2B is an enlarged view of the cross section of the skin having the foam layer. Since the foam layer 16 functions as a heat insulating layer as is well known, the base resin and the skin are surely bonded to each other. The foam layer 16 is made by double-foaming TPO, but other materials can be used as a matter of course. For example, the same PP as the base resin can be used to form the foam layer.

FIG. 3C is an enlarged view of the cross section of the skin provided with the non-woven fabric. The illustrated non-woven fabric 17 is made of PP. Since the surface of the non-woven fabric 17 has a large number of irregularities, the amount of heat escaping from the base resin through the non-woven fabric in the process of simultaneous molding and attachment is extremely small. The nonwoven fabric 17 also functions as a heat insulating layer. Therefore, if such a skin 12 is used, the base resin and the skin can be reliably bonded.

FIG. 2D shows modified polyamide and SEBS.
It is an enlarged cross-section of a skin provided with a mixture layer of (polystyrene-polyethylene / polybutylene-polystyrene). Since the mixture layer 18 has a lower melting point than the base resin and acts as an adhesive layer, it will be referred to as an adhesive layer. Further, the composition ratio of the modified polyamide and SEBS of this example is one to one, but if the composition and materials are changed, a mixture layer having an appropriate melting point depending on the melting point of the base resin used in each place. Is obtained.

Examples of materials that can be used for the adhesive layer include PE (polyethylene) and ionomers in addition to the above-mentioned modified polyamide (polyamide in which propylene and ethylene are block-copolymerized) and SEBS (polystyrene-polyethylene-polybutylene-polystyrene). Can be mentioned. These serve as an adhesive layer as a single substance or a mixture.

The ionomer is a thermoplastic polymer having a hydrophobic polymer main chain with a small amount of ionic groups in its side chain, terminal chain or main chain, and is suitable as a material for the adhesive layer. Ionomers include plastic, rubber and fluororesin membranes. The ionomer produced as a plastic is mainly a metal salt of a copolymer of ethylene and an unsaturated carboxylic acid, and is called an ethylene ionomer.

Now, a resin product was actually manufactured by using each skin shown in FIG. Here, for each skin material,
MI (melt index) is '25' [JIS-K
7210] was used for hot stamping. Then, when the adhesive strength in the peripheral portion was examined, the results shown in Table 1 were obtained.

[0026]

[Table 1]

For reference, Table 1 also shows a comparative example using a conventional skin. As shown in Table 1, as a result of using each skin of FIG. 1, a resin product in which the peripheral portion was not easily peeled off by hand was obtained.

[0028]

As described above, according to the inventions of claims 1 to 3, the molten base resin flows through the mold to be molded,
It is possible to reliably perform strong adhesion between the base resin and the epidermis during shaping and solidification. Further, according to the invention of claim 4, since the adhesive layer can be kept in a molten state for a relatively long time even after the base resin is solidified, the base resin is cooled faster than the adhesion.
Sufficient adhesion is possible even in the peripheral portion where solidification progresses.
Therefore, by using the present invention, it is possible to prevent the occurrence of a defective product in which the bonding fails and the peripheral portion is peeled off.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a manufacturing process by simultaneous molding and pasting.

[Explanation of symbols]

 10-13,22 Skin 15 Uneven part 16 Foam layer 17 Nonwoven fabric 18 Mixture layer 20 Upper mold 21 Lower mold 23 Base resin

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Claims (4)

[Claims] 1. A skin material which is adhered to a base resin in the same step as the molding of the base resin in the process of manufacturing a resin product, characterized in that at least one surface thereof has irregularities. Skin material. 2. A skin material that is adhered to a base resin in the same step as the molding of the base resin in the process of manufacturing a resin product, characterized by having a heat insulating layer on the surface on at least one side. Skin material to be used. 3. A skin material which is adhered to a base resin in the same step as the molding of the base resin in the process of manufacturing a resin product, characterized by having a non-woven fabric on the surface on at least one side. Skin material. 4. A skin material which is adhered to a base resin in the same step of molding the base resin in the process of manufacturing a resin product, and has a lower melting point than the base resin on at least one surface. A skin material having an adhesive layer.