JP2000301559A - Production of multi-layer molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a multi-layer molded article without crushing of a foamed layer and floating-up of a skin material and with good appearance while advantages of injection molding process and injection press molding process wherein at the same time when a base material is formed, the skin material is bonded on the surface are taken and even when the skin material with the foamed layer is used. SOLUTION: In a method for producing a multi-layer molded article wherein a skin material 1 is integrally bonded on at least a part of the surface of a base material consisting of a thermoplastic resin by feeding the skin material 1 at least with a foamed layer 3 between a pair of molds and feeding a molten thermoplastic resin between the skin material 1 and the molding face of a mold of one mold, when the molten thermoplastic resin 10 is fed, the multi-layer molded article is prepd. by partially placing an air-permeable sheet 5 in the surrounding of an opening part of a resin feeding gate between the molding face of a mold on the resin feeding gate side and the skin material 1.

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 multilayer molded article in which a skin material is bonded and integrated to at least a part of the surface of a substrate made of a thermoplastic resin.

[0002]

2. Description of the Related Art A multilayer molded product in which a skin material having a foamed layer is bonded and integrated on a surface of a base material made of a thermoplastic resin is used in automobile interior parts (for example, door trims and instrument panels) and home electric appliances. It is widely used in exterior parts and other wide fields.

Conventionally, as a method for producing such a multilayer molded article, for example, a skin material is bonded on a base material which has been previously produced by various methods such as injection molding or injection press molding, using an adhesive or the like. There are known a laminating method, a method in which a skin material is supplied between a pair of molds, and then a molten thermoplastic resin is supplied to form a desired shape, and at the same time, the skin material is bonded and integrated on a substrate surface. Have been.

However, in such a method, the former method has a complicated process and has a problem on the human body and the environment due to the solvent contained in the adhesive, and the latter method has a problem in forming a base material. At the same time, there is an advantage that the skin material can be bonded to the surface, but when the molten thermoplastic resin is supplied into the mold, the high-temperature, high-pressure molten resin comes into contact with the skin material, and the mold molding surface In addition, since the skin material is strongly pressed, there is a problem that the foam layer is crushed and the cushioning property is impaired.

To solve this problem, a method is known in which a backing layer is provided on the back surface of the skin material to protect the foamed layer from heat and pressure during resin supply. However, there is a problem that the foamed layer cannot be protected from the heat and pressure of the molten resin, and if the basis weight is too large, the shapeability deteriorates and the cost increases.

Another method is to place a non-breathable sheet member such as a polypropylene sheet or a polyvinyl chloride sheet partially between the periphery of the resin supply gate opening of the mold and the skin material, thereby forming a foam. It has been proposed to protect the layer from heat and pressure during resin supply (Japanese Patent Laid-Open No. 8-1).
No. 83059). However, according to this method, when the sheet member is arranged between the resin supply gate opening and the skin material and molded, the sheet member blocks the molten resin,
Because the molten resin is not impregnated between the sheet member and the foam layer, the sheet member and the foam layer do not adhere to each other, and the skin material of the portion corresponding to the periphery of the resin supply gate opening of the molded product rises,
There was a problem that the appearance was impaired.

[0007]

SUMMARY OF THE INVENTION
The present inventors take advantage of the injection molding method and the injection press molding method that the surface material can be bonded to the surface at the same time as forming the base material, and even when using the skin material having a foamed layer, As a result of studying to produce a multilayer molded article having a good appearance without collapse of the foam layer and no lifting of the skin material, the present invention was reached.

[0008]

That is, the present invention provides a skin material having at least a foamed layer between a pair of molds,
A molten thermoplastic resin is supplied between the skin material and the mold forming surface of one of the molds, and the skin material is laminated and integrated on at least a part of the surface of the base material made of the thermoplastic resin. A method of manufacturing a molded product, wherein, when a molten thermoplastic resin is supplied, a portion around a resin supply gate opening between a mold forming surface of a mold on a side having a resin supply gate and a skin material is partially removed. The present invention provides a method for producing a multilayer molded product, which comprises interposing a breathable sheet in the product.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for producing a multilayer molded product according to the present invention will be described.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The skin material applied to the method of the present invention needs to have at least a foamed layer. The skin material may be composed of only this foamed layer. Layers may be laminated, and a backing layer may be provided on the foam layer side. Further, the skin layer, the foam layer and the backing layer may each be a single layer, or may be two or more layers appropriately laminated. In particular, the skin layer and the foam layer each include a skin layer and a foam layer. The skin material provided is preferably used. Such a skin material,
Depending on the product shape, it may be preformed.

Examples of the foamed layer include soft or semi-rigid polyurethane foam, polypropylene foam,
Examples include polyethylene foam and polyvinyl chloride foam. These may have any thickness and density, but urethane foam having a density of 0.02 to 0.08 g / cm 3 is particularly preferably used.

As the skin layer, fabrics and knits such as moquettes and tricots, nonwoven fabrics such as needle punch carpets, metal foils, thermoplastic resins and thermoplastic elastomers can be used.
Sheet or film.

As the backing layer, a sheet or film made of non-woven fabric or synthetic resin is used. Examples of the fibers constituting the nonwoven fabric include natural fibers such as cotton, wool, silk, and hemp, and synthetic fibers such as polyamide, polyester, and nylon. These are used alone or as a blend to form a nonwoven fabric by various methods. For example, non-woven fabrics of a needle punch type, a thermal bond type, a spun bond type, a melt blow type, a spun lace type and the like can be used. Examples of the sheet or film made of a synthetic resin include a thermoplastic resin such as polypropylene or polyethylene and a sheet or film made of a polyolefin-based thermoplastic elastomer, and a material having an adhesive property with the thermoplastic resin used as the base resin. Is preferred. .

The air-permeable sheet applicable to the present invention includes woven fabrics, knitted fabrics, non-woven fabrics similar to those described above, and the like.
A sheet or film made of a thermoplastic resin or a thermoplastic elastomer, which is provided with air permeability by making holes, is used, and a nonwoven fabric is particularly preferred.

In the present invention, such a gas permeable sheet is provided with a resin supply gate opening between a mold forming surface of a mold having a resin supply gate and a skin material when the molten thermoplastic resin is supplied. It is important to partially intervene around the part.

Here, the periphery of the resin supply gate opening is defined as
It does not mean only the portion corresponding to the resin supply gate opening, but also the peripheral portion including the resin supply gate opening, and the size of the foam is opposite to the vicinity of the resin supply gate opening. The layer only needs to be large enough to be protected from the temperature and pressure of the supplied molten thermoplastic resin, and even if it is large enough to protect only the portion facing the resin supply gate opening, The size may protect a relatively wide range, and the size itself is not particularly limited.

As the thermoplastic resin applied to the present invention, any thermoplastic resin commonly used in extrusion molding, injection molding, press molding and the like can be used. For example, polyethylene, polypropylene, acrylonitrile Styrene-butadiene copolymer, polystyrene, polyamide such as nylon, polyvinyl chloride, polycarbonate, acrylic resin, general thermoplastic resin such as styrene-butadiene block copolymer, and thermoplastic elastomer such as EPM and EPDM. Or a polymer alloy using the same. The thermoplastic resin in the present invention includes all of them, and they may be foamable or non-foamable.

Such a thermoplastic resin may be blended with reinforcing fibers such as glass fibers and fillers such as various inorganic or organic fillers, if necessary. Various additives such as a pigment, a lubricant, an antistatic agent, and a stabilizer may be appropriately compounded.

As a molding method for obtaining the multilayer molded article of the present invention, an appropriate method such as an injection molding method or an injection press molding method is applied. Since the heat and pressure of the molten resin are directly applied to the material and the damage to the skin material may increase,
It is preferable to use an injection press molding method in which the mold is opened when the molten resin is supplied, and the mold is clamped after the supply of the molten resin or simultaneously with the completion of the supply, so that damage to the skin material can be reduced.

Hereinafter, a method for producing a multilayer molded product by injection press molding, which is a typical production method, will be described with reference to the drawings. Note that this description is an example of the present invention, and it goes without saying that the present invention is not limited to this.

FIG. 1 is a sectional view showing an example of a skin material (1) applied to the present invention. The skin material (1) is composed of a skin layer (2) and a foam layer (3). FIG. 3 is a cross-sectional view of another example of a skin material applied to the present invention, which includes a skin layer (2), a foam layer (3), and a backing layer (4).
It is composed of

FIGS. 3 to 6 show the resin supply gate opening between the mold surface of the mold on the side where the resin supply gate is located and the skin material during the supply of the molten thermoplastic resin in the method of the present invention. The state when a gas permeable sheet is partially interposed in the periphery is shown by the positional relationship between the skin material, the gas permeable sheet, and the resin supply gate opening.

The air permeable sheet partially intervenes around the resin supply gate opening between the mold surface of the mold on the side where the resin supply gate is located and the skin material when the molten thermoplastic resin is supplied. For example, in the case where the opening and closing direction of the mold is the vertical direction and the lower mold has a resin supply gate, the resin supply gate opening of the lower mold is provided. May be supplied so as to cover the air-permeable sheet, and a skin material may be placed on the air-permeable sheet. Alternatively, after supplying the skin material between the molds, the mold of the mold on the side having the resin supply gate may be supplied. The method is arbitrary, such as placing a permeable sheet so as to cover the resin supply gate opening provided on the molding surface.

In supplying the skin material, the skin material may be simply placed on the mold forming surface, or a pin or the like may be used for the male or female mold body or a skin material fixing frame provided around the body. The skin material peripheral portion may be fixed. The skin material may be preheated in advance, or may be preformed according to the product shape.

FIG. 7 shows a pair of male and female (6,
7 shows a state in which the skin material (1) and the breathable sheet (5) are supplied between the molds made of 7). As described above, when the molten thermoplastic resin is supplied, the air permeable sheet (5) partially surrounds the resin supply gate opening between the mold forming surface of the mold having the resin supply gate and the skin material. In the figure, the air permeable sheet is placed on the molding surface of the male mold (6) so as to cover the resin supply gate opening, and the skin material is shown in the figure. Is fixed to a skin material fixing frame (not shown) provided around the female mold (7).

FIG. 8 shows a resin supply passage (8) provided in the male mold between the air-permeable sheet (5) supplied between the molds and the mold forming surface of the male mold (6). The state where the molten thermoplastic resin (10) is supplied from the resin supply gate opening (9) is shown.

FIG. 9 shows a state in which the male and female molds are clamped after the supply of the molten thermoplastic resin. In this mold clamping step, the thermoplastic resin is shaped into a base material, The permeable sheet is impregnated into the air-permeable sheet or the molten resin passes through the voids and wraps around the skin material side, so that the skin material is firmly bonded and integrated with the base material through the air-permeable sheet . In addition, although the figure shows the example of the mold clamping in the vertical direction, the mold clamping direction may be the vertical direction or the horizontal direction. Further, the mold clamping may be started after the supply of the molten resin, or simultaneously with the completion of the supply or in parallel with the supply of the molten resin, and the mold clamping is performed simultaneously with or after the completion of the supply of the molten resin. May be completed.

When the mold clamping is completed, the molten resin is cooled and solidified, the mold is opened (FIG. 10), and the molded product is taken out.
As shown in FIG. 11, a multilayer molded article (11) in which a skin material is bonded and integrated on the surface of a base material made of a thermoplastic resin is obtained. Here, an example in which the skin material is bonded and integrated over the entire surface of the base material has been described. However, a multilayer molded product (12) in which the skin material is bonded to part of the base material as shown in FIG.
Except that the skin material is supplied to a desired position, it can be manufactured in the same manner according to the above method.

FIGS. 13 and 14 show detailed cross-sectional views of the multilayer molded product shown in FIG. 12. FIG. 13 shows that the skin material is composed of a skin layer and a foam layer, and FIG. This is an example composed of a foam layer and a backing layer.

[0030]

According to the method of the present invention, a skin material having a foamed layer can be obtained while taking advantage of the injection molding method and the injection press molding method in which a skin material can be bonded to the surface of the substrate at the same time as forming the base material. Even when it is used, a multilayer molded article having a good appearance without crushing of the foam layer or lifting of the skin material can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a skin material applied to the present invention.

FIG. 2 is a cross-sectional view showing another example of the skin material applied to the present invention.

FIG. 3 shows an example of a positional relationship between a skin material, a breathable sheet, and a resin supply gate opening when a molten thermoplastic resin is supplied in the method of the present invention.

FIG. 4 shows an example of a positional relationship between a skin material, a breathable sheet, and a resin supply gate opening when a molten thermoplastic resin is supplied in the method of the present invention.

FIG. 5 shows an example of a positional relationship between a skin material, a breathable sheet, and a resin supply gate opening when a molten thermoplastic resin is supplied in the method of the present invention.

FIG. 6 shows an example of a positional relationship between a skin material, a breathable sheet, and a resin supply gate opening when a molten thermoplastic resin is supplied in the method of the present invention.

FIG. 7 is a schematic cross-sectional view of a mold showing a manufacturing process according to the method of the present invention.

FIG. 8 is a schematic cross-sectional view of a mold showing a manufacturing process according to the method of the present invention.

FIG. 9 is a schematic cross-sectional view of a mold showing a manufacturing process according to the method of the present invention.

FIG. 10 is a schematic cross-sectional view of a mold showing a manufacturing process according to the method of the present invention.

FIG. 11 is a cross-sectional view showing an example of a multilayer molded product in which a skin material obtained by the method of the present invention is bonded and integrated over the entire surface of a substrate.

FIG. 12 is a cross-sectional view showing an example of a multilayer molded product in which a skin material obtained by the method of the present invention is bonded and integrated to a part of a substrate.

FIG. 13 is a detailed sectional view of a multilayer molded product obtained by the method of the present invention.

FIG. 14 is a detailed sectional view of a multilayer molded product obtained by the method of the present invention.

[Explanation of symbols]

 1: skin material 2: skin layer 3: foam layer 4: backing layer 5: breathable sheet 6: male type 7: female type 8: resin supply passage 9: resin supply gate opening 10: thermoplastic resin 11: multilayer molding Product 12: Multi-layer molded product

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takeo Kitayama 2-10-1 Tsukahara, Takatsuki-shi, Osaka Sumitomo Kagaku Kogyo Co., Ltd. F-term (reference) 4F204 AD16 AD17 AD20 AD35 AG03 AH25 AH26 AM32 FA01 FB01 FB13 FB20 FF05 FF49

Claims (4)

[Claims] 1. A thermoplastic material comprising: supplying a skin material having at least a foam layer between a pair of molds; supplying a molten thermoplastic resin between the skin material and a mold molding surface of one of the molds; A method for producing a multilayer molded product in which a skin material is bonded and integrated on at least a part of a surface of a resin base material, and a mold on a side having a resin supply gate when supplying a molten thermoplastic resin. A method for producing a multilayer molded product, characterized in that a permeable sheet is partially interposed around the resin supply gate opening between the mold forming surface and the skin material. 2. After supplying the skin material between the unclosed molds,
A method of supplying a molten thermoplastic resin between a skin material and a molding surface of a foam layer side of the skin material, clamping the mold, and laminating and integrating the skin material and the thermoplastic resin. Item 4. The method for producing a multilayer molded product according to Item 1. 3. The foamed layer is made of urethane foam.
The method for producing a multilayer molded article according to the above. 4. The method according to claim 1, wherein the air-permeable sheet is a nonwoven fabric.