JPH072439B2 - Transfer foil manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a thermal transfer foil used for surface decoration of a plastic molded product, and more particularly to a hairline-shaped product made of a coating film having high hardness on the surface of the transferred product. The present invention relates to a method for manufacturing a transfer foil for the purpose of forming irregularities.

(Prior Art) Conventionally, a transfer foil used for surface decoration of a plastic product is formed by applying a surface protective layer made of a thermoplastic resin such as acrylic resin on the surface of a transfer foil substrate,
Generally, a pattern layer, a masking layer, and an adhesive layer are sequentially formed, and therefore the surface hardness and durability of the final product were not sufficient. Therefore, particularly when surface scratch resistance is required, a complicated process of applying an ultraviolet-curable transparent paint (so-called hard coat) to the surface of the transfer product has to be taken.

Several methods have already been proposed for incorporating an ultraviolet-curable coating film into the transfer foil from the beginning.

However, the type of ink that gives sufficient adhesion to the UV-curable coating after curing is limited, so apply the UV-curable coating to the base film of the transfer foil and irradiate it with UV rays to cure it. After that, the transfer foil having practically sufficient adhesion could not be obtained by the method of successively forming the pattern layer, the masking layer, and the adhesive layer.

(Problems to be Solved by the Invention) The present invention is intended to solve the above-mentioned drawbacks of the prior art, and is excellent in interlayer adhesion only by transferring in the same manner as a normal transfer foil. Another object of the present invention is to provide a method for producing a transfer foil capable of obtaining a transfer product having hairline-shaped irregularities having strong surface scratch resistance and abrasion resistance.

(Means for Solving Problems) Hereinafter, the method of the present invention will be described in detail with reference to the drawings.

First, as shown in FIG. 2, a heat-sensitive adhesive (2) is applied to the surface of a printing substrate sheet (1) having releasability, and then a hiding layer (3) and a pattern layer (4) are sequentially printed. Since the base sheet is to be peeled off and removed in a later step, it is desirable that the base sheet be as inexpensive as possible. For example, a PET (polyethylene terephthalate) film, polypropylene film, polypropylene film laminated paper having a thickness of about 12 μ can be used. As the heat-sensitive adhesive, an appropriate one such as acrylic resin, polyamide resin, ethylene vinyl acetate resin, wax, chlorinated polypropylene resin, vinyl chloride vinyl acetate copolymer resin, etc. is selected according to the material of the final transfer product. The hiding layer and the pattern layer are selected in consideration of printability and adhesion to the electron beam curable resin used in the subsequent step. Acrylic resins, chlorinated rubber resins, vinyl chloride-vinyl acetate copolymer resins, etc. are common. Next, as shown in FIG. 3, the surface of the printed sheet (5) obtained as described above is coated with the electron beam curing type coating (6), and if necessary, heated to remove the solvent component in the coating. Then, PET with a thickness of about 25μ
After coating the film (7), the coating film is cured by irradiating an electron beam from the PET film surface, and then the printing substrate sheet (1) is peeled off and removed to obtain a transfer foil as shown in FIG. The electron beam curable coating used here uses a mixture of polyfunctional acrylic acid ester monomers such as trimethylolpropane triacrylate, polyfunctional methacrylate monomers such as dimethylolpropane dimethacrylate, and polyfunctional acrylic acid or methacrylic acid ester oligomers. Good to do. Hairline-shaped irregularities are formed in advance on the surface of the PET film used here in contact with the electron beam curable coating material. In order to form the hairline-shaped irregularities on the PET film, known methods such as a method by sandblasting, a method by hot pressure embossing, and a method of raising by printing can be applied.

(Example) A heat-sensitive adhesive mainly composed of an acrylic resin was applied to the entire surface of a raw material obtained by laminating polypropylene resin on a thin paper, and then a concealing layer was formed with a concealing ink corresponding to the solid color of a wood grain pattern. A wood grain pattern was printed on this.

For the hiding layer and the pattern layer, a vinyl chloride vinyl acetate copolymer resin-based ink was used.

On the surface of the printing sheet obtained as described above, 5 g / m ^{2 of} an electron beam curable coating containing oligoester acrylate and dimethylolpropane acrylate as main components was applied, and a convex portion with a height difference of about 5 μ was previously formed on the surface. 200 μm distance between the protrusions
Was coated with a PET film having a thickness of 25 μ on which hairline-shaped irregularities were formed, and an electron beam of 2.5 Mrad was irradiated onto the PET film using an electron beam irradiation device with an acceleration voltage of 200 KV to cure the paint.

Next, the polypropylene resin laminated paper was peeled off and removed to obtain a desired transfer foil.

The transfer foil thus obtained was transferred to the surface of a polystyrene resin molded product using a rubber roll heated to 210 ° C, and the PET film was peeled off and removed, and the surface had excellent scratch resistance and good interlayer adhesion. In addition, a wood grain transfer product having a hairline-shaped unevenness formed on the surface and having an extremely high design effect was obtained.

(Effects of the Invention) The method of the present invention is different from the conventional production of a transfer foil, in which an electron beam curable coating material corresponding to a surface protective layer is applied on a printed pattern layer previously formed on a releasable printing base sheet. After that, it is cured by irradiation with an electron beam, so that the adhesion between the electron beam-curable coating film and the pattern layer is good.

Further, since the PET film, which is the base sheet of the transfer foil, is coated on the electron beam curable coating material, there is an effect that curing inhibition by oxygen does not occur. In addition, since the surface protective layer of the transfer foil uses an electron beam curable paint, it is possible to obtain a transfer product with a high design effect that is extremely excellent in scratch resistance and abrasion resistance of hairline-shaped irregularities on the surface. can get.

[Brief description of drawings]

The drawings are for explaining the present invention. FIG. 1 is a schematic view showing a step of peeling and removing a printed base sheet, FIG. 2 is a sectional view showing a constitution of a printed sheet, and FIG. 3 is an electron beam irradiation. It is a schematic diagram which shows the state which is doing. (1) …… Printing base sheet (2) …… Heat-sensitive adhesive (3) …… Hiding layer (4) …… Picture layer (5) …… Printed sheet (6) …… Electron beam curable paint ( 7) …… PET film (8) …… Hairline-shaped irregularities (9) …… Electron beam irradiation device

Claims (1)

[Claims] 1. A method of manufacturing a transfer foil comprising the following steps. (1) A step of applying a heat-sensitive adhesive to a printing substrate sheet having releasability, and then printing and forming a hiding layer and a pattern layer. (2) An electron beam curable coating material is applied to the surface of the sheet obtained in (1), and then a polyethylene terephthalate film having hairline-shaped irregularities formed on the surface is coated thereon with the irregular surface facing downward. , A step of curing the coating material by irradiating it with an electron beam. (3) A step of peeling and removing the printing substrate sheet having releasability.