JP2000062396A - Thermal transfer film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer film without lowering an adhesive strength of a transferred design by transferring the design to an article having a surface misalignment of a protrusion and recess pattern, embossing, a stepwise difference or the like. SOLUTION: The thermal transfer film comprises a support film having a base film 1 and a film 2 made of different type resin formed on the film 1, a release layer 3 formed on the different type resin side surface of the support film, a design layer 4 formed on the layer 3, and an adhesive layer 5 formed to cover the layer 3 and the layer 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer film, and more specifically, a pattern, letters, other information or the like on the surface of an article having irregularities, textures, steps, etc. (hereinafter collectively referred to as "pattern"). The said) is used for forming by thermal transfer.

[0002]

2. Description of the Related Art A transfer film is preferably used when a pattern is applied to the surface of a resin product or a metal product. The transfer film basically has a structure in which a release layer, a pattern layer and an adhesive layer are provided in this order on the support film. The transfer film is adhered to the product surface by the adhesive layer and the support film is released. A pattern is formed on the product surface by peeling off the layer and leaving the pattern on the product surface.

When the transfer film is adhered to the surface of the product,
Usually, the transfer film is pressed by a heat roll, but if the product surface has surface irregularities such as irregularities, textures or steps, there is a problem that the adhesive strength of the transferred pattern is reduced. Further, there is a problem that the pattern cannot be completely transferred when the degree of unevenness, texture, steps, etc. becomes large.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermal transfer film capable of transferring a pattern to an article having surface irregularities such as irregularities, textures and steps, and the adhesive strength of the transferred pattern is not lowered. It is what

[0005]

The object of the present invention is to provide a support film comprising a base film and a film made of a different resin formed on the base film, a release layer formed on the surface of the support film on the different resin side, It is achieved by a thermal transfer film including a pattern layer formed on the release layer and an adhesive layer formed so as to cover the release layer and the pattern layer.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION A sectional view of a typical example of a transfer film of the present invention is shown in FIG. The transfer film of FIG. 1 has a base film 1, a heterogeneous resin film 2, a release layer 3, a pattern layer 4, and an adhesive layer 5, and the base film 1 and the heterogeneous resin film 2 form a support film. There is.

As the base film of the present invention, polyester (for example, polyethylene terephthalate, polybutylene terephthalate, etc.) which has been used as a support film for a conventional transfer film can be used. Among them, polyethylene terephthalate is preferable.

In the present invention, the heterogeneous resin means a resin different from the resin constituting the base film. For example, when the base film is formed of polyester, a resin other than polyester, for example, polyethylene (for example, low density linear film) is used. Polyolefin) such as polyethylene) and polypropylene; ethylene copolymer resins such as ethylene-vinyl acetate resin, ethylene-acrylic acid resin and ethylene-ethyl acrylate resin; ionomer resins; and ionic polymers. Especially, polyethylene is preferable.

When transferring a pattern to an article, the heat transfer film is usually pressed by a heat roll, but when the surface of the product is matte, the support film is peeled off on the line where the heat roll first contacts the heat transfer film. A parting line remains afterwards, that is, the degree of matting appears different on both sides of the line.To solve the problem of parting lines, one or both of the base film and the dissimilar resin film forming the support film are used. A matte film, so-called matte film may be used. Such a matte film is a matte film produced by matting the film surface by blasting, or a matte film produced by forming a matte layer (matte coating) on a resin film by coating, Alternatively, it may be a matte film formed from a resin in which an inorganic or organic powder, preferably an extender pigment is kneaded. Preferably, the base film is a film whose surface is matted by blasting, a film having a mat layer formed by coating on a resin film, or a mat film formed from a resin in which powder is kneaded. The dissimilar resin film used is a film whose surface is matted by blasting or embossing, or a matte film formed from a resin in which powder is kneaded.

The thickness of the base film and the different resin film depends on the degree of surface irregularity of the article on which the pattern is to be transferred,
For example, it is appropriately determined according to the size of the unevenness. When transferring to a preformed molded article by a hot roll, the thickness of the base film is usually 4 to 25 μm, preferably 5 to 2
0 μm, and the thickness of the different resin film is usually 5 to 60
μm, preferably 10 to 50 μm. On the other hand, when transferring simultaneously with injection molding, the thickness of the base film is 2
5 to 50 μm, preferably 30 to 45 μm, and the thickness of the different resin film is 5 to 60 μm, preferably 10 to 50 μm.
It is 50 μm. Different resin films are made of different resins.
It may be a layered structure of layers or more.

The different resin film of the present invention is preferably formed by extrusion laminating the different resin on the surface of the base film. The extrusion laminating may be performed using a T-die laminator, a tandem laminator, a forced laminator, or the like.

The material for the release layer may be one used in conventional thermal transfer films, such as acrylic resin,
Examples include hydrocarbon resins, vinyl chloride resins, waxes, and the like. The release layer is formed by applying these release materials to the surface of the support film by a conventional method, for example, gravure coating.

Designs such as characters and figures are printed on the release layer. The printing ink may be selected appropriately depending on which material is printed. As the printing machine, a gravure printing machine, a silk screen printing machine or the like can be used. The pattern layer can be formed by using these printing machines alone or in combination. Further, in order to diversify the design, a metal layer may be added by vapor deposition.

Finally, an adhesive layer is formed on the printed layer. The adhesive may be the one used in the conventional thermal transfer film, and may be selected according to the material of the mating article to be transferred.

Examples of the article on the surface of which the pattern is formed by using the heat transfer film of the present invention include plastic strong grain molding, plastic strong step molding, and porous articles such as wood and pottery. , Plastic flower pots, manual operation tools for family computers, wooden body brush handles, etc.

A hard coat layer may be used to impart physical properties, particularly surface abrasion resistance, to the transferred pattern layer. The hard coat layer can be provided between the release layer and the different resin film in place of the release layer or in addition to the release layer. The hard coat layer is formed of an electron radiation curable resin and / or an ultraviolet curable resin. Examples of electron radiation curable resins include prepolymers having an ethylenically unsaturated bond, such as unsaturated polyesters;
Acrylates such as polyester acrylate, epoxy acrylate, urethane acrylate, polyether acrylate, polyol acrylate, melamine acrylate; methacrylates such as polyester methacrylate, epoxy methacrylate, urethane methacrylate, polyether methacrylate, melamine methacrylate, etc. Can be used alone or as a mixture of two or more.

A reactive diluent may be added to these prepolymers to control the viscosity and the physical properties of the cured film. As the reactive diluent, a compound having an ethylenically unsaturated bond or thiols can be used. For example, styrene-based monomers; acrylic acid esters such as 2-ethylhexyl acrylate; methacrylic acid esters; unsaturated carboxylic acid amides; substituted amino alcohol esters of unsaturated acids; ethylene glycol diacrylate, propylene glycol diacrylate, etc. Functional compounds; polyfunctional thiols such as trimethylolpropane trithioglycolate and trimethylolpropane trithiopropionate. These may be used alone or in combination of two or more, if necessary.

As the ultraviolet curable resin, the same resin as the above electron beam curable resin is used, and as the polymerization initiator, a usual ultraviolet polymerization initiator such as benzoyl ethers,
A chemical compound such as halogenated acetophenones, benzophenones, diacetyls, etc. that generates radicals by ultraviolet irradiation is added. As a coating film forming method, a conventionally known coating method such as a roll coater method or a gravure coating method can be adopted.

The electron radiation curable resin or the ultraviolet curable resin may be irradiated with an electron beam or an ultraviolet ray in a state of being applied at this stage, or may be cured at any stage after the next step. In any case, the thermal transfer film is cured before being used for transfer.

[0020]

EXAMPLES The thermal transfer film of the present invention will be specifically described with reference to the following examples. Example 1 A polyethylene terephthalate film (thickness: 12 μm) transferred to a molded product was extruded and laminated with a polyethylene film (thickness: 16 μm) and used as a support film. A release layer made of an acrylic resin (thickness: 1
~ 2μm), a pattern layer made of chlorinated rubber ink (thickness 1 ~
3 μm), adhesive layer made of chlorinated polypropylene resin
Gravure printing (thickness 1 to 2 μm) was performed to prepare a thermal transfer film.

Next, using the above-mentioned transfer sheet, a polypropylene molded article having an uneven surface is coated with a silicone rubber roll (hardness 50) to obtain a roll surface temperature of 230 ° C.
Thermal transfer was performed under the conditions of a pressure of 00 kgf and a transfer speed of 8 cm / sec. All the patterns were completely transferred following the surface irregularities of the molded product, and the transferred patterns were not peeled at all in the adhesive tape peeling test. A transfer foil comparable to the transfer foil for a normal flat surface was obtained.

Example 2 A polyethylene terephthalate film (thickness: 38 μm) injection-molded simultaneously transferred and a polyethylene film (thickness: 30 μm) extruded and laminated onto the polyethylene film side was used as a supporting film. 1
˜2 μm), and then print a picture layer made of vinyl acrylic gravure ink, and finally gravure print a vinyl acrylate adhesive layer (thickness 2-3 μm) to obtain a heat transfer film for in-mold molding. Created.

Next, the above-mentioned transfer sheet is mounted in an injection molding die having an uneven surface on the surface of the die, and at the same time when the die is closed, a melted acrylic resin (resin temperature 230 ° to 23 °).
2 ° C) was injected into the mold. Molding was completed in an injection molding cycle of 60 seconds, and the molded article with the painting was taken out. The peeling layer, the pattern layer, and the adhesive layer followed the steps of the product and were completely transferred. The transferred pattern was not peeled at all in the adhesive tape peeling test, and it was found that the pattern had sufficient adhesion and scratch resistance. In this way, a picture-formed molded article equivalent to the transfer to the ordinary plastic molded article having a smooth surface was obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a preferred embodiment of a transfer film of the present invention.

[Explanation of symbols]

1 ... Substrate film, 2 ... Different resin film, 3 ... Release layer, 4 ... Design layer, 5 ... Adhesive layer.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Taiji Sano             51-1 Hirakawahamaura, Joyo-shi, Kyoto Prefecture Royal             Industry Co., Ltd. (72) Inventor, Koji Gotani             51-1 Hirakawahamaura, Joyo-shi, Kyoto Prefecture Royal             Industry Co., Ltd. F term (reference) 3B005 EB01 FA04 FA12 FB03 FB11                       FB13 FB18 FC02X FC08X                       FC08Y FE05 FG04X GA02

Claims (4)

[Claims] 1. A support film comprising a base film and a film made of a different resin formed on the base film, a release layer formed on the surface of the support film on the different resin side, and a release layer formed on the release layer. A thermal transfer film comprising a pattern layer and an adhesive layer formed so as to cover the release layer and the pattern layer. 2. The base film is formed from a film whose surface is matted by blasting, a film having a mat layer formed by coating on a resin film, or a resin in which powder is kneaded. The thermal transfer film according to claim 1, which is a matte film. 3. The thermal transfer film according to claim 1, wherein the heterogeneous resin film is a film whose surface is matted by blasting or embossing, or a mat film formed from a resin in which powder is kneaded. . 4. The thermal transfer according to claim 1, further comprising a hard coat resin layer in place of the release layer or in addition to the release layer, between the different resin film and the release layer. the film.