JPH0530167B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Fields] The composite molded product of the present invention can be used as lining insulation materials for the main body and doors of refrigerators, door materials for show window cases and unit baths that require heat insulation, and automobiles that require cushioning properties. It is useful as automobile interior materials such as bumpers and door trims, surfboards, etc. [Prior art] Acrylonitrile-butadiene-styrene copolymer, which is a styrene resin, is used for the body and doors of refrigerators to prevent rust on the baked-on stainless steel or steel plate structural base material (outer frame) and to form shelves. (commonly known as ``ABS'') sheets are vacuum formed, pressure-formed, formed using a combination of vacuum and pressure-formed air (hereinafter, these forming methods are collectively referred to as thermoforming), or injection molded. There is. Also
Instead of ABS lining material, it has been proposed to use polypropylene lining material, which has excellent surface gloss, low water absorption, and is economically advantageous. In order to improve the heat insulation properties of these lining materials, it has been proposed to interpose foamed polyurethane between the structural base and the lining material (Japanese Patent Application Laid-Open No. 1983-1999).
No. 97841). Furthermore, the door materials for unit baths are currently made from polyvinyl chloride sheets, but when used at high temperatures, the aluminum sash frame has the problem of corroding due to the chlorine gas generated by decomposition. In order to improve the door, we are considering attaching two polypropylene sheets to an aluminum sash frame instead of using polyvinyl chloride sheets, and filling the space between the aluminum sash frame and the sheet with foamed polyurethane to give it more rigidity as a door. ing. Furthermore, with the transition from metal to resin for interior materials such as automatic door trims, filling polyurethane foam by injection method is being considered for the purpose of cushioning or heat insulation. As described above, there is a demand for composites of resin materials and foamed polyurethane in resin products with various complex shapes. [Problems to be solved by the invention] However, resin materials are usually used as sheets or made into molded products by thermoforming or injection molding, and when polyolefin resin in such a shape is used, foaming Due to the insufficient adhesion to polyurethane, voids are formed, which has the disadvantage that the purpose of rigidity and heat insulation cannot be fully achieved. In order to improve the adhesive strength between this resin material and foamed polyurethane, it is possible to apply liquid adhesive or adhesive liquid or treat the surface with chemicals (Japanese Patent Application Laid-Open No. 60-97841).
However, the addition of complicated steps due to an increase in the number of coating steps and surface treatment steps is not preferable. In addition, the resin layer that adheres to the urethane foam is
It is necessary that the material is not easily corroded by the Freon gas mixed in the urethane. The present invention eliminates such treatment steps, is resistant to corrosion by Freon gas, and is economically and cheaply bonded to urethane foam by blending an ethylene acrylic acid copolymer or the like with an olefin resin that advantageously bonds to urethane foam. It improves strength. (Structure of the Invention) The present invention provides a composite molded article having a structure in which a resin molded article having the following composition and a urethane foam are integrally laminated. Resin composition (A) Olefin resin 40-85% by weight (B) Ethylene/acrylic acid random copolymer with MFR of less than 30 g/10 minutes 60-15% by weight (A) The olefin resin for component is polyethylene, Resins such as polypropylene, ethylene-propylene copolymer, ethylene-propylene-butene copolymer, etc. can be used, and these can be used alone or as a mixture. In particular, the ethylene content is 2
~12% by weight propylene-ethylene block copolymer or a mixture of 50-90% by weight polypropylene and 50-10% by weight polyethylene is preferred. This olefin resin is made of polyamide, ABS,
Resins such as ethylene/vinyl acetate copolymers, stabilizers, rubbers, pigments, and inorganic fillers may also be blended. The ethylene/acrylic acid random copolymer of component (B) has an MFR of less than 30 g/10 min, preferably 2 to 20 g/10 min, as measured at 190°C according to JIS K-6760.
g/10 min, and is a relatively high molecular weight resin obtained by random copolymerization of 70 to 99% by weight of ethylene and 30 to 1% by weight of acrylic acid. Such products are manufactured by Mitsubishi Yuka Co., Ltd. as “Yukalon EAA”.
A221M”, “Yukalon EAA A200K”, “Yukalon
EAA The adhesion to the product is low, making it impractical.On the other hand, if the content exceeds 60% by weight, the mold releasability may deteriorate when vacuum forming, press forming, pressure forming, or injection molding a sheet made of a resin composition. In order to improve this mold release property, if necessary, a styrene resin may be added to reduce the amount of ethylene/acrylic acid copolymer added. Examples of such styrene resins include polystyrene, ABS, and SBS. ,
SA, HIPS, etc. can be used. Among these
ABS has better adhesion to urethane foam. However, the olefin resin of component (A) in the resin alone does not have adhesive properties with the urethane foam. This resin composition is melt-kneaded using an extruder, fed to an extrusion die, extruded into a sheet or parison, and then vacuum-formed, compression-molded, or blow-molded, and used as refrigerator lining material and surfboards. be done. Molded objects such as bumpers are injection molded. The surfaces of these molded bodies may be subjected to corona discharge treatment, flame treatment, or plasma treatment, if necessary. (Composite molded product) A composite molded product is one in which a urethane foam and the resin molded product are bonded together. A surf-in board is manufactured by injecting a foaming polyurethane liquid into the hollow part of the blow-molded product and causing the foam to form. When used as an interior material for a refrigerator, as shown in FIG. 1, a foamable urethane solution 4 is injected into a cavity 3 formed by a mold 1 made of a decorative steel plate and the vacuum-formed product 2, and then By foaming and curing, a composite molded body in which the mold 1, the urethane foam 4', and the lining material 2 are integrated is manufactured. Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that parts and percentages in the examples are based on weight. Example of sheet production 1 80% by weight of a crystalline propylene-ethylene block copolymer with an ethylene content of 5% by weight, MFR of 0.5g/10 minutes, and a residual amount of 98% by weight after extraction with boiling heptane, and ethylene manufactured by Mitsubishi Yuka Co., Ltd.・Acrylic acid (8.5wt%) random copolymer “EAA A221M” (product name, MFR7
g/10 minutes) and 20% by weight was kneaded using an extruder, extruded into strands, and cut into pellets. The above pellets were processed using an extruder with a diameter of 90 mmφ.
The mixture was melted and kneaded at 230°C and supplied to a manifold flat die with a width of 700 mm. The molten sheet extruded from the die was sequentially cooled and solidified by three rolls with a width of 800 mm. The temperature of the rolls was 40°C, 80°C, and 60°C starting from the roll closest to the die, and the rotational speed of the rolls was 1.5 m/min. The sheet thickness was 1.5 mm. Examples 2 to 9 Resin sheets were obtained in the same manner as in Example 1, except that the composition of the resin was changed as shown in Table 1. The abbreviations in the table are as follows. PP: Propylene/ethylene block copolymer E/AA: Ethylene/acrylic acid random copolymer A200K: Ethylene/acrylic acid copolymer manufactured by Mitsubishi Yuka Co., Ltd. (acrylic acid content 7% by weight, MFR5g/
10 minutes)
g/10 minutes) A221M: Ethylene/acrylic acid copolymer manufactured by Mitsubishi Yuka Co., Ltd. (acrylic acid content 8.5% by weight, MFR7
g/10 minutes) A500W: Ethylene/acrylic acid copolymer manufactured by Mitsubishi Yuka Co., Ltd. (acrylic acid content 20% by weight, MFR300
g/10 minutes) PS: Polystyrene "Dialex TH516" (trade name) manufactured by Mitsubishi Monsanto Chemical Co., Ltd. SBS: SBS "Tuffrene A" (trade name) manufactured by Asahi Kasei Corporation Example 1 Resin sheet obtained in Example 1 above was introduced into a heating furnace set at approximately 230℃ using a vacuum/pressure forming machine, and a combination of compressed air (5.0Kg/cm ² ) and reduced pressure (-600mmHg) was used.
Plug assist molding (drawing ratio H/D=1/
1). The release properties of the sheet were good, and the plug was easily separated from the sheet. After drilling an injection port in a part of this shaped sheet, this sheet is inserted into a stainless steel frame that is the frame of the refrigerator body, and then the space (cavity) formed by the frame and the shaped sheet is inserted. When a two-component foaming urethane solution "HM-1510" (trade name) manufactured by Polyurethane Kagaku Kasei Co., Ltd. was injected into the space from the injection port, foaming started after 10 seconds, and after 1 minute, the space was filled with urethane. Completely filled with foam.The density of this urethane foam is 0.05g/cm ²
It was hot. The same operation was repeated 20 times to obtain 20 composite molded body samples. After 24 hours, the sheet adhered to the urethane foam was cut out, and the adhesion between the urethane foam and the sheet was measured by the following method. After separating the urethane foam from the sample piece by hand, use a knife to cut 100 1 mm squares into the sheet containing the remaining urethane foam, then stick adhesive tape on the squares, and forcefully pull the adhesive tape from the sheet. When the sheet was removed, the squares of urethane foam remaining on the sheet side were examined. The results are shown in Table 1. The evaluation criteria for adhesion are as follows. ○: Cohesive failure of urethane foam ×: Adhesion between the urethane foam and the resin layer is weak, and the sheet is easily peeled off from the interface with the urethane foam. Examples 2 to 6, Comparative Examples 1 to 3 Composite molded bodies were obtained in the same manner except that the resin sheets in Example 1 were replaced with those in Examples 2 to 9. Table 1 shows the adhesion between the urethane foam and the sheet of these composite molded bodies.

[Table] Example 7 A mixture of 80% by weight of the propylene/ethylene block copolymer used in Example 1 and 20% by weight of the ethylene/acrylic acid random copolymer "A221M" was melted at approximately 220°C using an extruder. The mixture was kneaded, fed into one die, extruded into a parison shape, and then hollow-molded to obtain a molded product for a surf-inboard. A two-component urethane solution was injected into the hollow part of this molded body and foamed to obtain a surf inboard. The adhesion between the urethane foam and the resin layer of this product was stronger than that of Example 2. Example 8 The same resin as in Example was used. (PP80% by weight, E・AA “A221M” 20% by weight). Injection molding machine
Injection pressure 100 at a temperature of about 220℃ using 800 tons
A molded body for a bumper was obtained by injection molding in a mold at a mold temperature of 60° C. at kg/cm ² . This molded product was placed in a foam frame, and a two-component urethane solution was injected and foamed to obtain a bumper for an automobile. Table 1 shows the adhesion between the urethane foam and the molded product.

[Brief explanation of the drawing]

The figure is a sectional view showing one embodiment of the present invention. In the figure, 1 is a stainless steel frame, 2 is a resin sheet (lining material), 3 is a cavity, 4' is a urethane foam,
5 is an injection port.

Claims (1)

[Scope of Claims] 1. A composite molded product having a structure in which urethane foam and a resin molded product having the following composition are laminated together. Resin composition (A) Olefin resin 40-85% by weight (B) Ethylene/acrylic acid random copolymer with MFR less than 30 g/10 minutes 60-15% by weight 2 Olefin resin has an ethylene content of 2-12% by weight The composite molded article according to claim 1, which is a propylene-ethylene block copolymer. 3. The composite molded article according to claim 1, wherein the olefin resin is a mixture of polypropylene and polyethylene, and the blending ratio is 50 to 90% by weight of polypropylene and 50 to 10% by weight of polyethylene.