JPH11207898A - Substitute coated film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excellent substitute coated film used for manufacturing a beautiful injection-molded article, where a coloring excellent in designing characteristics is applied without applying a coat, by preforming the film, fixing it in an injection mold cavity, and integrally molding with an injected resin for forming a colored layer of the injection-molded article. SOLUTION: A substitute coated film is a composite film composed by sequentially laminating a transparent layer, a colored layer, an adhered layer, and a base layer. The base layer is composed of a propylene/ethylene block copolymer, or a mixture comprising 30-80 pts.wt. propylene monopolymer and 20-70 pts.wt. linear low-density polyethylene.

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 susceptible to deterioration in appearance due to the occurrence of surface irregularities, which is called a shading phenomenon, during the heat treatment stage of preforming, and this phenomenon does not disappear even after injection molding, and as a result, the image becomes clearer. There was a problem that it was not possible to obtain a highly molded product.

[0005]

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

[0006]

Means for Solving the Problems The present inventors 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 of a specific composition 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 sheet in which a transparent layer, a coloring layer, an adhesive layer and a base layer are sequentially laminated, wherein the base layer is a propylene / ethylene block copolymer or propylene alone. 30 to 80 parts by weight of polymer and linear low density polyethylene 20 to
70% by weight of the mixture.

[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 alternative 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 The amount may be appropriately selected in consideration of the dispersibility 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 The component forming the adhesive layer, which is a constituent layer of the above-mentioned coating alternative film used in the present invention, may be any material that sufficiently adheres the base material layer and the colored layer, and may be chlorinated polyethylene or chlorinated polyethylene. A chlorinated polyolefin-based resin such as polypropylene (including these acrylic modified resins), or a laminate of an 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 an acrylic resin and a chlorinated polyolefin-based resin, the acrylic resin layer is used as the side in contact with the colored layer, the chlorinated polyolefin-based resin layer is used as the side in contact with the base layer, and the acrylic resin is used for the colored layer. It is preferable to use the same resin as the resin, and it is preferable that the chlorinated polyolefin resin is appropriately selected depending on the blending of the polyolefin resin.

4. Substrate layer The polyolefin resin used for forming the substrate layer, which is a constituent layer of the above-mentioned alternative coating film used in the present invention, is a propylene / ethylene block copolymer or a propylene homopolymer of 30 to 80 parts by weight and is linear. Low density polyethylene 2
It is a mixture with 0 to 70 parts by weight. If the blending amount of each of the propylene / ethylene block copolymer and the propylene homopolymer blended with the linear low-density polyethylene is more than 80 parts by weight, the temperature range of the preforming becomes narrow and the moldability deteriorates. On the other hand, when the amount is less than 30 parts by weight, adhesion to a general polyolefin resin used for a molded article such as an automobile exterior part becomes poor, and heat resistance also decreases.
When a propylene / ethylene block copolymer is used, a molded article having better impact resistance can be obtained. The thickness of the base material layer 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.

Production of Paint Replacement Film In the present invention, each of the above 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 colored layer, and the adhesive layer can also be formed by extrusion molding depending on the type of the selected resin. The substrate layer may also be formed and laminated into a film by a conventionally known T-die extrusion method or the like.

The coating layer comprising the transparent layer, the colored layer and the adhesive layer formed on the release film formed by the above method and the base material layer formed into a film are thermally laminated at a temperature not lower than the softening point of the resin for the adhesive layer. 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.

[0015] 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, after heating the above-mentioned film from both sides using a far-infrared ceramic heater, the mold is moved up, down, left and right, a part of the heated composite film is brought into contact with the mold, and By vacuuming the air between the mold and the vacuum through a vacuum hole in the mold, the film surface is brought into close contact with the mold, fixed and shaped, and cooled and fixed by a forced cooling method using a blower or the like. Is preferred. 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 has the same shape as that of 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.

Also, in order to prevent the resin injected and injected from the gate from flowing around the cavity from the preform, and to prevent the occurrence of wrinkles due to welding, the type, number, position, direction and shape of the gate are also changed. Care must be taken.
In particular, as the type of gate, a direct gate, a submarine gate, or the like is preferable, and as the number of gates, it is necessary to consider the component shape, the fluidity of the injection resin, and the like.
It is desirable to be a 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 component in which the above-mentioned preform is integrated is obtained.

[0019]

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 8 a) Preparation of a coating substitute film 1) Preparation of a polyolefin resin film to be used as a base material layer
A sheet was formed by a die extrusion method to obtain a polyolefin resin film.

2) Preparation of Coating Layer (Adhesive Layer / Coloring Layer / Transparent Layer) The coating layer was prepared by successive coating on a release polyester film so as to have the composition 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 After evaluating the vacuum forming temperature range of the coating substitute film obtained in a), vacuum forming is performed at an appropriate temperature.
A preform having the shape shown in FIG. 1 was produced. Specifically, the vacuum forming temperature is 1 in Examples 1 and 2, respectively.
45 ° C, 120 ° C in Comparative Examples 1 and 3, Comparative Example 2,
4, 160 ° C. in Comparative Example 5, 135 ° C.
In Comparative Examples 6 and 8, the temperature was 140 ° C, and in Comparative Example 7, the temperature was 150 ° C. The approximate size of the molded product is
The length is 150 mm, the width is 70 mm, and the thickness is 8 mm. After inserting and fixing the prepared preform into the cavity surface of the injection mold, the mold is clamped and the injection resin BC2
E (polypropylene resin manufactured by Nippon Polychem Co., Ltd.) was injected to obtain a molded product.

C) Evaluation of Molded Product 1) Evaluation of Vacuum Formability The temperature range in which vacuum forming is possible is evaluated using an evaluation die (vacuum forming die) having a drawing ratio of 0.3 to 0.5, and the results are shown in Table. No. 1. The evaluation results are as follows. Good moldability ○>△> × Inferior moldability (Wide molding temperature range) (Narrow molding temperature range) 2) Evaluation of appearance of molded product The 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: Visual No shading->>> x Shark's writing-60 ° gloss: Handy gloss meter HG-268 manufactured by Suga Test Instruments Co., Ltd. was used. Image sharpness: A portable image sharpness measuring instrument HA-NSIC manufactured by Suga Test Instruments Co., Ltd. was 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.

[0023]

[Table 1]

The mixing ratio of the polyolefin resin is as follows. a: propylene homopolymer / linear low density polyethylene =
6/4 b: propylene / ethylene block copolymer / linear low density polyethylene = 6/4 c: propylene homopolymer / linear low density polyethylene =
2/8 d: propylene homopolymer / linear low density polyethylene =
9/1 e: propylene / ethylene block copolymer / linear low density polyethylene = 2/8 f: propylene / ethylene block copolymer / linear low density polyethylene = 9/1 g: propylene / ethylene random copolymer / Linear low density polyethylene = 6/4 h: propylene homopolymer / low density polyethylene = 6 /
4i: propylene homopolymer / high density polyethylene = 6 /
4j: Propylene / ethylene block copolymer / low-density polyethylene = 6/4 The components used in the evaluation are the following products. Propylene homopolymer: EA7 manufactured by Nippon Polychem Co., Ltd.
(Product abbreviation) Propylene / ethylene block copolymer: Nippon Polychem Co., Ltd. product EC9 (Product abbreviation) Propylene / ethylene random copolymer: Nippon Polychem Co., Ltd. product EG7 (Product abbreviation) Linear low-density polyethylene: Nippon Polychem Product UF Co., Ltd.
230 (product abbreviation) Low density polyethylene: LF24, a product of Nippon Polychem Co., Ltd.
0 (Product abbreviation) High-density polyethylene: HJ34, a product of Nippon Polychem Co., Ltd.
0 (product abbreviation) PVDF: Polyvinylidene fluoride resin Kynar 301F (trade name) manufactured by Penwort Company PMMA: Polymethyl methacrylate resin Elbasite 2010 (trade name) manufactured by DuPont Sparkle Silver 3141-ST: Si
lberline Manufacturing C
o. Product

[0025]

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 Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // B29K 105: 20 623: 00 627: 12 633: 00 (72) Inventor Takemoto Nakai Oike Iwatsuka-cho, Iwatsukacho, Nakamura-ku, Nagoya-shi, Aichi Prefecture. No. 2 Mitsubishi Chemical MKV Corporation Nagoya Office (72) Inventor Yuji Takeda 2 Okaike Iwatsukacho, Nakamura-ku, Nagoya City, Aichi Prefecture 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 base layer are sequentially laminated, wherein the base layer is a propylene / ethylene block copolymer or a propylene homopolymer in an amount of 30 to 80% by weight. A coating substitute film comprising a mixture of a low-density polyethylene and 20 to 70 parts by weight of linear low-density polyethylene. 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 coating according to claim 1, wherein the coloring layer comprises a coloring agent and a mixture of a thermoplastic acrylic resin or a fluororesin and a thermoplastic acrylic resin, and the thickness of the coloring layer is 5 to 50 μm. 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.