JPH11207896A - Painting alternative film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excellent paint substitute film used for producing a beautiful colored injection molded product excellent in design without relying on painting. This film is preformed, secured in an injection mold cavity, and integrally molded with the injected resin to produce a colored molded article. SOLUTION: This is a composite film in which a transparent layer, a colored layer, an adhesive layer, and a base layer are sequentially laminated, wherein the base layer is a laminate of a polyolefin resin, and the side in contact with the adhesive layer is propylene alone. A coating substitute film characterized by being a polymer layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paint substitute film having excellent appearance after molding, and more particularly to a paint substitute film for forming a colored coating layer on the surface of a molded product produced by injection molding simultaneously with injection molding. It is about a film.

[0002]

2. Description of the Related Art Plastic automotive exterior parts such as bumpers and side moldings are mostly formed by injection molding. However, in most cases, acrylic-modified melamine-based or acrylic-modified isocyanate is used from the viewpoints of design and scratch resistance. The coating is applied by a method of spray-coating a thermosetting resin paint of a system onto a molded article, followed by baking. In other words, after applying a paint through a multi-step process in a coating facility, the plastic injection molded product requires many steps of drying in a drying facility, so that painting is expensive. there were. In addition, there is also a problem that there is a concern about workplace environmental hygiene and environmental protection due to volatile organic solvent emission during drying.

[0003] In recent years, studies have been made to solve or alleviate such a problem.
Japanese Patent No. 3077 discloses that after preforming a composite sheet composed of a transparent layer, a coloring layer, and a backup sheet (base layer), the composite sheet is inserted into a mold in advance, and synthetic resin is injection-molded to form an integrated sheet. To obtain a colored molded article has been proposed.

In recent years, polyolefins have been developed for automobile parts, and accordingly, there have been many demands for composite sheets as described above, which use a polyolefin resin for the base material layer. Various sheets are being considered. However, these composite sheets are generally liable to deteriorate in appearance due to the occurrence of surface unevenness called a shark soldering phenomenon in a pre-molding heat treatment stage, and this phenomenon does not disappear even after injection molding, and as a result, an image There was a problem that it was not possible to obtain a molded product with high illuminance.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a coating substitute film for improving the above-mentioned drawbacks and obtaining a colored injection-molded article such as an automobile exterior part having an excellent appearance.

[0006]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, the use of a composite film having a base material layer made of a polyolefin-based resin having a specific structure has led to the problems described above. Have been found to be able to solve the problem. That is, the gist of the present invention is a composite film in which a transparent layer, a colored layer, an adhesive layer, and a base layer are sequentially laminated, wherein the base layer has a multilayer structure of a polyolefin resin, and The coating replacement film is characterized in that the side in contact with the adhesive layer is a propylene homopolymer layer.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. Component of each layer of coating substitute film Transparent layer As a component forming the transparent layer, which is one constituent layer of the above-mentioned coating substitute film used in the present invention, a mixture of a fluororesin and a thermoplastic acrylic resin is suitable.As the fluororesin, polyvinyl fluoride, Polyvinylidene fluoride,
Fluororesins such as polytetrafluoroethylene and ethylene-tetrafluoroethylene copolymer can be used, but polyvinylidene fluoride (PVDF), which has good moldability during preforming, is preferable. On the other hand, as the thermoplastic acrylic resin, various thermoplastic acrylic resins including a methacrylate ester resin can be used, but from the viewpoint of the scratch resistance of the molded product surface, the glass transition temperature (Tg) is 60 ° C. It is preferable that the degree is not less than about.

The mixing ratio of the fluororesin to the thermoplastic acrylic resin is preferably in the range of 20 to 80 parts by weight of the fluororesin and 80 to 20 parts by weight of the thermoplastic acrylic resin.
If the amount of the fluororesin is more than 80 parts by weight, the scratch resistance is inferior. If the amount is less than 20 parts by weight, the weather resistance is reduced and the impact resistance is also reduced. The thickness of the transparent layer is preferably from 20 to 100 μm, and if it is thinner than 20 μm, the appearance of the molded product (particularly the feeling of depth) is reduced, and conversely,
Even if it is thicker, there is no improvement effect on appearance, physical properties, etc., and it is not preferable in terms of cost.

[0009] 2. Coloring layer As a component forming the coloring layer, which is a constituent layer of the above-mentioned coating substitute film used in the present invention, a thermoplastic acrylic resin or a mixture of a fluororesin and a thermoplastic acrylic resin is useful, weather resistance, pigment dispersion. It may be appropriately selected in consideration of properties and the like. However, if the amount of the fluororesin exceeds 90 parts by weight, it is difficult to obtain sufficient adhesion to the base material layer, which is not preferable.

The coloring agent used in the coloring layer may be selected from inorganic pigments, organic pigments, and the like. Examples thereof include carbon black, titanium oxide, kaolin clay, zinc white, red iron, permanent red, molybdenum orange, cobalt blue, and ultramarine blue. Phthalocyanine blue, manganese violet and the like. These pigments, alone,
Two or more combinations can be used. In addition, aluminum flakes and pearl pigments may be added to the above-mentioned pigments in order to obtain a metallic tone and a pearl tone. Coloring layer thickness is 5-5
A thickness of 0 μm is preferable, and a thickness of less than 5 μm is not preferable because the color of the stretched portion in preforming greatly changes. Further, even if the thickness is more than 50 μm, the effect of improving the performance is small and the cost is not preferable.

3. Adhesive layer As a component forming an adhesive layer which is a constituent layer of the above-mentioned coating alternative film used in the present invention, any material may be used as long as it sufficiently adheres the polypropylene homopolymer layer of the base material layer and the coloring layer, A chlorinated polyolefin-based resin (including this acrylic-modified resin) or a laminate of a thermoplastic acrylic resin and a chlorinated polyolefin-based resin can be used. As the chlorinated polyolefin resin, chlorinated polypropylene is particularly preferred. When using a laminate of a thermoplastic acrylic resin and a chlorinated polyolefin-based resin, the thermoplastic acrylic resin layer is on the side in contact with the coloring layer, the chlorinated polyolefin-based resin layer is on the side in contact with the base layer, and the acrylic resin is It is preferable to use the same resin as that used for the coloring layer.

4. Substrate Layer The substrate layer, which is a constituent layer of the above-mentioned alternative coating film used in the present invention, is composed of a laminate of a polyolefin resin, and the side in contact with the adhesive layer is a propylene homopolymer layer. The polyolefin-based resin layer laminated with the propylene homopolymer layer preferably has sufficient adhesiveness to the propylene homopolymer and is excellent in preformability by thermoforming, for example, a mixture of polyethylene and polypropylene, polyethylene, and polypropylene. , And ethylene
Mixtures of propylene rubber and the like are preferred.

The base material layer may contain other polyolefin resins, additives, fillers and the like as long as physical properties and moldability are not impaired. May be taken. The thickness of the base material layer having the above-mentioned configuration is preferably in the range of 0.1 to 1 mm in order to suppress the shape retention after the pre-molding and the destruction due to the injection pressure at the time of the injection molding and the melting due to the heat from the injection resin. Further, the thickness of the propylene homopolymer layer is preferably 0.05 to 0.5 mm from the viewpoint of appearance after molding and preformability.

Production of Paint Substitution Film In the present invention, each of the above-mentioned layers can be produced as follows. For the formation of the transparent layer, the coloring layer, and the adhesive layer,
It is preferable to use a release film. That is,
A resin obtained by dissolving or dispersing the resin forming each layer in an organic solvent can be formed by successively coating a releasable film by a conventionally known reverse roll coating method, a comma coating method or the like, and an adhesive layer. If the film thickness is small, a gravure coating method can also be used.

Further, the transparent layer, the coloring layer, and the adhesive layer
Depending on the type of resin selected, it can also be formed by extrusion molding. The base material layer can be formed into a film by forming and laminating by coextrusion. In co-extrusion molding, usually, the material constituting each layer is melt-kneaded by each extruder, and each layer is sequentially laminated using a feed block, then extruded from a T-die and cooled by a molding roll or the like.
A method of solidifying and winding the laminated film using a winding machine is employed.

[0016] A coating layer comprising a transparent layer, a colored layer and an adhesive layer formed on the release film formed by the above method and a substrate layer formed into a film are thermally laminated at a temperature not lower than the softening point of the adhesive layer resin. After lamination, the release film is peeled off to obtain a coating substitute film of the present invention. As the release film, a polyethylene terephthalate film is preferable from the viewpoint of heat resistance during thermal lamination.

[0017] For automotive parts and the like using a paint substitute film
Molding The coating substitute film obtained by the above method is then preformed by thermoforming to form a three-dimensional molded body having a shape corresponding to the part. As thermoforming, vacuum forming, pressure forming,
A molding method such as vacuum pressure molding is suitable, but vacuum molding is particularly convenient and preferred.

In vacuum forming, for example, the above film is heated from both sides using a far-infrared ceramic heater, and then the mold is moved up, down, left, and right, and a part of the heated film is brought into contact with the mold. By vacuuming the air between the mold and the vacuum hole in the mold,
It is preferable to form the film by closely fixing the film surface to a mold, and to cool and fix the film by a forced cooling method using a blower or the like. Also, in order to make the elongation of the film during vacuum forming uniform over the entire part, after heating the film and before evacuation, while blowing air from the direction in contact with the mold to expand the heated film into a hemisphere, There is also a method of molding, which is particularly suitable for molded parts with deep drawing.

Next, injection molding of a molded article using the obtained coating substitute film is performed in the same shape as the three-dimensional molded body obtained by preforming as described above, and is hard and free of surface defects. After inserting the preform into a pair of injection molds having a cavity having a high gloss and highly polished surface, the mold is closed, and the molten resin is injected and injected.
In this case, it is necessary to take care that the preform fixed in the mold does not turn up or move from the mold.

The type, number, position, direction, and shape of the gates are also set to prevent the resin injected and injected from the gates from flowing around the cavity from the preform and to prevent wrinkles due to welding. Care must be taken.
In particular, as the type of gate, a direct gate, a submarine gate, and the like are good, and as the number of gates, it is necessary to consider the component shape, the fluidity of the injection resin, and the like.
Desirably one point. After injecting and injecting the molten resin, the mold is cooled, the mold is opened, the molded product is taken out, and a colored molded product in which the preform is integrated is obtained.

[0021]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. Examples 1 and 2 and Comparative Examples 1 to 5 a) Preparation of a substitute coating film 1) Preparation of a polyolefin resin film to be used as a base layer In the configuration shown in Table 1, the first layer (adhesive layer side) was used. 1m
m, the second layer is 0.4 mm, and the total thickness is 0.5 mm.
It was formed into a film by a co-extrusion method using a die to obtain a polyolefin resin film.

2) Preparation of Coating Layer (Adhesive Layer / Coloring Layer / Transparent Layer) On the release polyester film, it was successively coated so as to have the constitution shown in Table 1. Each layer was formed by a reverse roll coating method after being dissolved in a soluble organic solvent such as toluene, methyl ethyl ketone, and γ-butyrolactone. After each layer obtained in 1) and 2) was thermally laminated at a temperature of 150 ° C. and a pressure of 10 kg / cm ² , the release film was peeled off to obtain a coating substitute film.

B) Molding of parts Using the film obtained in a), vacuum molding is performed as shown in FIG.
A preform having the shape shown in Table 1 was produced. The approximate size of the molded product is 150 mm in the longitudinal direction and 70 mm in the lateral direction.
mm and 8 mm in the thickness direction. After inserting and fixing the prepared preform into the cavity surface of the injection mold, the mold is clamped, and the polypropylene resin (Nippon Polychem Co., Ltd. product BC
2E) was injected and injected to obtain a molded product.

C) Evaluation of molded article The molded article obtained in b) was evaluated for its appearance, 60 ° gloss,
And the image definition were evaluated, and the results are shown in Table 1. still,
The measuring method is as follows. -Appearance: No visual shading->△> x Shark-60 ° gloss: Handy gloss meter HG-268 manufactured by Suga Test Instruments Co., Ltd.・ Image sharpness: A portable image sharpness measuring instrument HA-NSIC manufactured by Suga Test Instruments Co., Ltd. is used. Note that the 60 ° gloss and the image clarity are the figures obtained in b).
The measurement was performed on a flat portion of a molded article having the shape shown in FIG.

[0025]

[Table 1]

The components used in the evaluation are as follows. a) Propylene homopolymer: Nippon Polychem Co., Ltd. product E
A7 (product abbreviation) b) Homopolymer of propylene: Nippon Polychem Co., Ltd. product E
A9 (product abbreviation) c) Propylene / ethylene random copolymer: Nippon Polychem Co., Ltd. product EG7 (product abbreviation) d) Propylene / ethylene block copolymer: Nippon Polychem Co., Ltd. product EC7 (product abbreviation) e) Propylene Homopolymer / low density polyethylene = 6 /
4 blended product Low density polyethylene: Nippon Polychem Co., Ltd. product LF24
0 (product abbreviation) f) propylene homopolymer / high density polyethylene = 6 /
4 high density polyethylene: Nippon Polychem Co., Ltd. product HY43
0 (product abbreviation) PVDF: Polyvinylidene fluoride resin Kyner 301F (product of Penwort) PMMA ^* : Polymethyl methacrylate resin Elbasite 2010 (product of DuPont) Sparkle Silver: Silverline
Manufacturing Co. Product

[0027]

The paint substitute film of the present invention has a good preformability by thermoforming and an excellent appearance after preformation, so that it is a beautiful bumper, side molding,
It is particularly suitable for manufacturing molded articles such as automobile exterior parts such as mudguards, wheel caps, spoilers, and the like.

[Brief description of the drawings]

FIG. 1 is a perspective view of a preform of a coating substitute film of the present invention.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Somoto Nakai 2 Oike, Iwatsuka-cho, Nakamura-ku, Nagoya-shi, Aichi Prefecture Mitsubishi Chemical MKV Corporation Nagoya Office (72) Inventor Yuji Takeda Oike, Iwatsuka-cho, Nakamura-ku, Nagoya-shi, Aichi Prefecture No. 2 Mitsubishi Chemical MKV Corporation Nagoya Office

Claims (4)

[Claims] 1. A composite film in which a transparent layer, a colored layer, an adhesive layer, and a substrate layer are sequentially laminated, wherein the substrate layer is a laminate of a polyolefin-based resin, and the side in contact with the adhesive layer is propylene. A coating substitute film, which is a homopolymer layer. 2. The transparent layer comprises a fluororesin and a thermoplastic acrylic resin, and has a thickness of 20 to 100.
The coating substitute film according to claim 1, which has a thickness of μm. 3. The colored layer according to claim 1, wherein the colored layer comprises a coloring agent and a mixture of a thermoplastic acrylic resin or a fluororesin and a thermoplastic acrylic resin, and the colored layer has a thickness of 5 to 50 μm. Painting alternative film. 4. The coating substitute film according to claim 1, wherein the adhesive layer comprises a chlorinated polyolefin resin layer or two layers of a thermoplastic acrylic resin layer and a chlorinated polyolefin resin layer.