JPH02187B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a coating layer, in which a coating layer made of vinyl chloride resin or ABS resin is laminated on the surface of a polypropylene molded article via a special adhesive layer. The present invention relates to a method of manufacturing a molded article.

Molded objects made of polypropylene have excellent mechanical strength and are used in various fields.
It is very difficult to print or paint the surface of the molded product, and it is impossible to create various shapes and patterns on the surface of the molded product, making it difficult to use it for decorative purposes. I couldn't do it.

Therefore, on the surface of the polypropylene molded body,
It has been proposed to laminate a coating layer made of vinyl chloride resin or ABS resin, which has excellent printability, paintability, and design properties.

However, polypropylene and vinyl chloride resin or ABS resin do not bond even if they are directly laminated, and no adhesive has been found that can strongly bond the two. It has been almost impossible to form a coating layer made of vinyl chloride resin or ABS resin that is strongly bonded to the surface.

The inventors conducted extensive research with the aim of obtaining a molded article with a coating layer, in which a vinyl chloride resin or ABS resin coating layer is strongly bonded to the surface of a polypropylene molded article. result,
It has been discovered that the above object can be achieved by the special adhesive used in this invention,
completed this invention.

That is, an adhesive whose main component is at least one resin selected from the group consisting of vinyl chloride-ethylene-vinyl acetate copolymer, acrylic monomer-ethylene-vinyl acetate copolymer, and chlorinated polypropylene. Fixing the layered vinyl chloride resin or ABS resin coating preform in an injection mold so that the polypropylene supplied in a molten state can come into contact with the adhesive layer. A movable mold corresponding to the fixed mold is placed along the inner surface of the mold, the mold is closed by closely contacting the fixed mold, and the mold is heated to approximately 210 to 300°C. With a coating layer, the coating layer is formed by injecting polypropylene in a molten state and simultaneously performing injection molding, and at the same time laminating a coating layer formed from the preform onto the surface of the injection molded product via the adhesive layer. The invention relates to a method for producing molded bodies.

The molded article with a coating layer obtained by the method of the present invention has a coating layer laminated on the surface of the polypropylene molded article via the above-mentioned adhesive layer, and has a peel strength of at least 1.0 kg/cm. It is strongly bonded and has excellent durability.

According to the method of this invention, even if the surface of a polypropylene molded article having a complicated curved surface is coated,
The coating layer is free from wrinkles, lifting, tearing, etc., and the above-mentioned excellent molded article with the coating layer can be obtained.

Below, this invention will be explained with reference to the drawings.
I will explain in more detail.

FIG. 1 is a sectional view showing an example of a molded article with a coating layer obtained by the method of the present invention, and FIG. FIG. 2 is a cross-sectional view schematically showing a state in which a molded body is manufactured.

The adhesive layer 2 used in this invention is at least one selected from the group consisting of vinyl chloride-ethylene-vinyl acetate copolymer, acrylic monomer-ethylene-vinyl acetate copolymer, and chlorinated polypropylene. It is made from an adhesive whose main component is resin.

In addition to the resins mentioned above, the adhesives include polyethylene, polypropylene, polyvinyl chloride, polystyrene, ethylene-propylene copolymer,
(MI; 3-200g/10 minutes, VA content 2-50%)
Contains thermoplastic resins such as ethylene-vinyl acetate copolymers, acrylonitrile-ethylene-styrene copolymers, etc. outside the range of MI and vinyl acetate unit content in a proportion of about 50% by weight or less, especially 30% by weight or less may have been done.

In addition, in this invention, the vinyl chloride-ethylene-vinyl acetate copolymer or the acrylic monomer-ethylene vinyl acetate copolymer used as the main component of the adhesive layer has an ethylene unit content of 55 to 90%. The vinyl acetate unit content is 5 to 30%, and the total content of ethylene and vinyl acetate units is
The softening temperature is about 75 to 97%, and the softening temperature is 25%.
It is preferable that the temperature is about 50°C. In the above-mentioned acrylic monomer-ethylene-vinyl acetate copolymer, the acrylic monomer includes acrylic acid,
Examples include methacrylic acid, esters of (meth)acrylic acid with methyl alcohol, ethyl alcohol, and propyl alcohol, and (meth)acrylonitrile.

Furthermore, in this invention, the chlorinated polypropylene used as the main component of the adhesive layer has a chlorination rate of
Preferably, the content is 20 to 45% by weight, particularly 25 to 35% by weight, and the softening temperature is about 25 to 50°C.

In this invention, by using the adhesive layer mainly composed of the above-mentioned resin, the coating layer 3 made of vinyl chloride resin or ABS resin is applied to the surface of the polypropylene molded body 4 with a strong adhesive layer. The adhesive layer can be laminated by adhesive force, and as shown in Comparative Examples 1 and 2, adhesive layers mainly composed of other resins similar to the above-mentioned resins can be laminated on the surface of polypropylene molded objects. A molded article with a coating layer having a strongly bonded coating layer cannot be obtained.

In the method of the present invention, the preformed body 3' for coating with vinyl chloride resin or ABS resin provided with an adhesive layer is prepared by applying an adhesive mainly composed of the above-mentioned resin to toluene, n-hexane, Methyl ethyl ketone (MEK), methyl isobutyl ketone,
A sheet or film in which an adhesive layer is provided by applying a solution dissolved in an organic solvent such as ethyl acetate to one side of a vinyl chloride resin or ABS resin sheet or film, and removing the organic solvent from the thin film of the adhesive solution by evaporation. Alternatively, the adhesive may be extruded into a film and thermally laminated on one side of a vinyl chloride resin or ABS resin sheet (film) to provide an adhesive layer. Then, the sheet (film) provided with the adhesive layer is formed into a preformed body (inner layer shape of a mold for producing a polypropylene molded body) by pressure forming, vacuum forming, or other sheet forming. It can be manufactured by a method of molding into a shape corresponding to

In the method of the present invention, the preformed body 3' for coating of vinyl chloride resin or ABS resin provided with the adhesive layer 2 is formed by supplying molten polypropylene and applying pressure to form the polypropylene. Although it is preferable that the molding die 5 has a shape that allows them to be brought into close contact with each other along the inner surface of the mold 5, it is not necessary that the molding die 5 and the preform 3' match in detail.

In this invention, the vinyl chloride resin refers to a vinyl chloride polymer, a copolymer of vinyl chloride containing 60% or more of vinyl chloride units, and other monomers.
A thermoplastic resin containing 60% by weight or more, in particular 60% by weight or more, in addition to the vinyl chloride polymer or copolymer described above, other synthetic resins such as ethylene-vinyl acetate copolymer, ABS resin, One type or a mixture of two or more of MBS resins, acrylic resins, etc. may be contained in a proportion of less than about 50% by weight, particularly 40% by weight or less. Preforms molded using vinyl chloride resin are molded from vinyl chloride resin containing various additives such as plasticizers, fillers, reinforcing agents, dyes, pigments, etc. It may be something that has been done.

In addition, in this invention, ABS resin is
It is a thermoplastic resin containing 50% by weight or more, especially 60% by weight or more of acrylonitrile-butadiene-styrene copolymer, and in addition to the ABS copolymer, other synthetic resins such as polyvinyl chloride, ethylene- One or a mixture of two or more of vinyl acetate copolymer, MBS resin, acrylic resin, etc.
It may be contained in a proportion of less than 50% by weight, especially 40% by weight or less. Note that the preform molded using ABS resin may be molded from ABS resin containing various additives as appropriate.

The sheet (film) made of vinyl chloride resin or ABS resin used for molding the above-mentioned preform has an average thickness of about 0.01 to 2 mm, especially 0.1 mm.
It is preferable that the sheet has a thickness of ~1 mm, and the surface of the sheet may be decorated by printing a pattern such as wood grain.

In this invention, the average thickness of the adhesive layer provided on the sheet is preferably about 5 to 500 microns, particularly about 10 to 300 microns. If the thickness of the adhesive layer is too small, it is not preferable because a coating layer that strongly adheres to the surface of the polypropylene molded article cannot be laminated.

In this invention, the polypropylene is
Any type of polypropylene that has been conventionally used for molding may be used, and the polypropylene may be blended with conventionally known additives, fillers, and the like.

In the method of this invention, the above-mentioned adhesive layer 2
A preformed body 3' made of a vinyl chloride resin or ABS resin is placed along the inner surface of the molding die 5 so that the polypropylene supplied in a molten state can come into contact with the adhesive layer. Molten polypropylene is supplied into the mold and pressurized, and at the same time the polypropylene is molded, the coating layer 3 molded from the preform is bonded to the molded body using an adhesive layer. A molded article with a coating layer is produced by laminating it on the surface.

In the method of the present invention, molten polypropylene is fed into a mold and pressurized to form a polypropylene molded body. Injection molding method is optimal.

In the method of the present invention, for example, the coating preform 3' provided with the adhesive layer 2 described above is placed in the mold along the inner surface of the fixed mold 5 for injection molding. The movable mold 6 corresponding to the fixed mold is brought into close contact with the fixed mold, the mold is closed, and the inside of the mold is moved.
Polypropylene in a molten state heated to about 210 to 300° C. is injected and, at the same time, the coating layer 3 formed from the preform is applied to the surface of the injection molded product through the adhesive layer 2. Layer them together.
A method for molding the molded article 1 with a coating layer can be mentioned.

In the method of the present invention, by injecting the heated polypropylene as described above, a molded article with a coating layer is produced in which the preformed article arranged as described above and the injection molded article of polypropylene are firmly adhered. Obtainable.

According to the method of the present invention, it is possible to obtain a beautiful molded article with a coating layer, which has a coating layer of vinyl chloride resin or ABS resin strongly adhered to the surface of a polypropylene molded article.

The molded article with a coating layer obtained by the method of the present invention is a polypropylene molded article having a beautiful coating layer with excellent durability, so it can be used as a decorative case for furniture, electrical appliance cases, bags, etc. It can be used for various purposes.

Examples and comparative examples are shown below. In the following description, parts indicate parts by weight.

Example 1 Resin composition consisting of 100 parts of ABS resin (acrylonitrile content: 25% by weight, butadiene content: 30% by weight, styrene content: 45% by weight) and 1 part of higher alcohol (carbon number: 16 to 18) A wood grain print is applied to the surface of an ABS resin sheet (average thickness: approx. 0.5 mm) that is molded using a calendar roll method using a material, and chlorinated polypropylene (chlorination rate: 25% by weight) is printed on the back side of the sheet. %) toluene solution (polymer concentration: 33% by weight) was applied and dried.
An adhesive layer was provided with an average thickness of approximately 15μ.

This ABS resin sheet with an adhesive layer is vacuum formed to fit the inner surface of an injection mold to form a preformed ABS resin coating with an adhesive layer. was formed.

This preform is placed along the inner surface of a fixed mold for injection molding, the mold is closed, and molten polypropylene heated to approximately 230°C is injected into the mold to form the injection mold. Then, the mold was cooled, opened, and the molded article with the coating layer was taken out.

This molded article with a coating layer had a beautiful wood grain pattern in which the ABS resin coating layer was integrally laminated on the surface of the polypropylene molded article.

Cut out a part of this molded product with a coating layer,
When the adhesive force between the ABS resin coating layer and the polypropylene molded article was measured, the peel strength (180 degrees) at a peel rate of 50 mm/min was 2.6 kg/cm.

Example 2 Instead of a toluene solution of chlorinated polypropylene, vinyl chloride-ethylene-vinyl acetate copolymer (vinyl chloride content: 19%, ethylene content: 57
%, vinyl acetate content; 24%) toluene and n-
A molded article with a coating layer was obtained in the same manner as in Example 1, except that a mixed solvent solution with hexane (polymer concentration: 31% by weight) was used.

This molded product with a covering layer has a covering layer with a beautiful wood grain pattern laminated on the surface of a polypropylene molded product, and when the adhesive strength was measured in the same manner as in Example 1, it was found to be similar to that of a polypropylene molded product. The peel strength (180 degrees), which indicates the adhesive strength with the ABS resin coating layer, was 1.6 kg/cm.

Example 3 Instead of a toluene solution of chlorinated polypropylene, methyl methacrylate-ethylene-vinyl acetate copolymer (methyl methacrylate content: 17
%, ethylene content; 55%, vinyl acetate content;
A molded article with a coating layer was obtained in the same manner as in Example 1, except that a mixed solvent solution (polymer concentration: 38% by weight) of toluene and n-hexane (28%) was used.

This molded product with a coating layer has a beautiful wood grain pattern.
It has a coating layer made of ABS resin, and the adhesive force of the coating layer to the molded object is the peel strength (180
degree) was excellent, as indicated by 2.2Kg/cm.

Comparative Example 1 A MEK solution (polymer concentration: 55% by weight) of vinyl chloride-methyl methacrylate copolymer (vinyl chloride content: 80% by weight) was used instead of a toluene solution of chlorinated polypropylene. A molded article with a coating layer was obtained in the same manner as in Example 1.

However, the ABS resin coating layer of the molded product with a coating layer easily peels off from the edges of the molded product.
In addition, the coating layer lifted up in the concave portions of the molded product, and it was of no practical value.

Comparative example 2 MI is 20g/10min, VA content is 28%
Instead of ethylene-vinyl acetate copolymer, which has an MI of 2 g/10 min and a VA content of 5%
A molded article with a coating layer was obtained in the same manner as in Example 2, except that the ethylene-vinyl acetate copolymer was used.

In this molded article with a coating layer, the vinyl chloride resin coating layer easily peeled off from the edges, and the coating layer lifted up in the recessed parts of the molded article, so it was of no practical value. .

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of a molded article with a coating layer obtained by the method of the present invention, and FIG. FIG. 2 is a cross-sectional view schematically showing a state in which a molded body is manufactured. 1... Molded body with coating layer, 2... Adhesive layer, 3...
...covering layer made of vinyl chloride resin or ABS resin, 3'...preformed body, 4... molded body made of polypropylene, 5...fixed mold, 6...movable mold.

Claims (1)

[Claims] 1. Adhesive layer whose main component is at least one resin selected from the group consisting of vinyl chloride-ethylene-vinyl acetate copolymer, acrylic monomer-ethylene-vinyl acetate copolymer, and chlorinated polypropylene. PVC resin or
A covering preform made of ABS resin is placed along the inner surface of the fixed mold of the injection mold so that the polypropylene supplied in a molten state can come into contact with the adhesive layer. Then, the movable mold corresponding to this fixed mold is brought into close contact with the fixed mold, and the mold is closed.
Polypropylene in a molten state heated to approximately 210 to 300°C is injected into the mold, and at the same time, a coating layer formed from the preform is applied to the surface of the injection molded product. A method for producing a molded article with a covering layer, characterized by laminating the molded article with an adhesive layer interposed therebetween.