JPH054920B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for producing thermal transfer foil used for surface decoration of plastic molded products, and in particular, the present invention relates to a method for producing thermal transfer foil used for surface decoration of plastic molded products. This invention relates to a method for manufacturing transfer foil for the purpose of forming.

(Prior art) Transfer foil, which has been conventionally used for surface decoration of plastic products, is made by coating the surface of a transfer foil base film with a surface protective layer made of thermoplastic resin such as acrylic resin, and then applying a pattern layer. , a hiding layer and an adhesive layer are generally formed in sequence, and therefore the surface hardness and durability of the final product are not sufficient. For this reason, especially when scratch resistance on the surface is required, a complicated process of applying an ultraviolet curable transparent paint (so-called hard coat) to the surface of the transfer product has been necessary. Several methods have already been proposed for incorporating an ultraviolet curable coating film into a transfer foil from the beginning.

However, the types of ink that can provide sufficient adhesion to the UV-curable paint film after curing are limited, so the UV-curable paint is applied to the base film of the transfer foil and cured by irradiating it with UV light. After that, by sequentially forming a pattern layer, a hiding layer, and an adhesive layer, a transfer foil with practically sufficient adhesion could not be obtained.

(Problems to be Solved by the Invention) The present invention can create a curved pattern with excellent interlayer adhesion and strong scratch resistance and abrasion resistance on the surface by simply transferring it using the same method as ordinary transfer foil. The present invention presents a method for manufacturing a transfer foil that can obtain a transfer product having the following characteristics.

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

First, as shown in FIG. 2, a heat-sensitive adhesive 2 is applied to the surface of a printing base sheet 1 having mold releasability, and a concealing layer 3 and a pattern layer 4 are sequentially printed. Since the base sheet is to be peeled off and removed in a subsequent process, it is desirable to use something as inexpensive as possible; for example, PET (polyethylene terephthalate) film, polypropylene film, polypropylene film laminated paper, etc. with a thickness of about 12 μm can be used. As the heat-sensitive adhesive, an appropriate one is selected depending on the material of the final transfer product, such as acrylic resin, polyamide resin, ethylene-vinyl acetate resin, wax, chlorinated polypropylene resin, vinyl chloride-vinyl acetate copolymer resin. The hiding layer and pattern layer are selected in consideration of printability and adhesion to the ultraviolet curable resin used in the subsequent process. Acrylic resin, chlorinated rubber resin, vinyl chloride vinyl acetate copolymer resin, etc. are common. Next, as shown in FIG. 3, an ultraviolet curable paint 6 is applied to the surface of the printed sheet 5 obtained in the above manner, and if necessary, heating is performed to remove the solvent in the paint. The surface of the PET film 7 coated with a PET film 7 having a diameter of about 25 μm is irradiated with ultraviolet rays to cure the paint, and then the printing base sheet 1 is peeled off and removed as shown in FIG. 1 to obtain a transfer foil. As the ultraviolet curable paint used here, it is preferable to use a high-hardness type of known acrylic oligomer-based ultraviolet curable paints. used here
On the surface of the PET film that comes into contact with the ultraviolet curing paint, a varnish layer 8 having a desired curvature adjusted in advance is formed in a pattern. At this time, if a varnish layer having a different length from the length adjusting varnish layer 8 is formed on the entire surface of the PET film, a pattern having an arbitrary difference in length can be formed.

The varnish adjustment layer and the varnish layer different from this varnish layer must have adhesive properties to the PET film and releasability to the ultraviolet curable coating film, and must have thermosetting polyester resin. , polyamide resin, urethane resin, etc. are suitable.

(Example) A heat-sensitive adhesive mainly composed of acrylic resin is applied to the entire surface of the original fabric made of thin paper laminated with polypropylene resin, and then a concealing layer is formed with a concealing ink corresponding to the solid color of the wood grain pattern, and then A wood grain pattern was printed on top of this.

Vinyl chloride vinyl acetate copolymer resin ink was used for the hiding layer and the pattern layer.

The surface of the printed sheet obtained above was coated with an acrylic resin-based ultraviolet curable paint (Mitsubishi Rayon Co., Ltd.).
5g/m ² of 5g/m 2 (manufactured by Mimaki Co., Ltd.) was coated, and a 25μ thick PET film was coated with a 25μ thick PET film on which a varnish adjustment varnish layer of polyamide resin was previously formed in a checkered pattern, and a high-pressure mercury lamp was applied over this The paint was cured by irradiating it with ultraviolet light.

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

The transfer foil obtained in this way is transferred onto the surface of a polystyrene resin molded product using a rubber roll heated to 210°C, and when the PET film is peeled off and removed, the surface has excellent scratch resistance and good interlayer adhesion. In addition, a wood grain transfer product with an extremely high design effect having a lattice-like grain pattern on the surface was obtained.

(Effects of the Invention) According to the manufacturing method of the present invention, an ultraviolet curable paint corresponding to a surface protective layer is coated on a pattern layer and a concealing layer formed in advance on a releasable printing base sheet. , because it is cured by irradiation with ultraviolet rays, there is strong adhesion (adhesion) due to chemical bonds between the ultraviolet curable paint, the pattern layer, and the concealing layer, and the pattern layer and concealing layer provided by printing methods have minute irregularities. It becomes possible to generate strong adhesion (adhesion) due to physical bonding such as a buried anchor effect.

Furthermore, since the ultraviolet curable paint is cured while being sandwiched between the printing base sheet and the PET film, it also has the effect of not being inhibited by oxygen.

Therefore, the ultraviolet curable paint film serving as the surface protective layer has extremely excellent scratch resistance, and a transfer product with excellent design effect, which also has excellent abrasion resistance of the curved pattern on the surface, can be obtained.

[Brief explanation of the drawing]

The drawings are for explaining the method of the present invention, and FIG. 1 is a schematic diagram showing the process of peeling off the printed base sheet, FIG. 2 is a cross-sectional view showing the structure of the printed sheet, and FIG. FIG. 3 is a schematic diagram showing a state of irradiation. 1... Printing base sheet, 2... Heat-sensitive adhesive,
3... Hiding layer, 4... Pattern layer, 5... Printed sheet, 6... Ultraviolet curable paint, 7... PET film, 8... Line adjustment varnish layer, 9... Ultraviolet irradiation device.

Claims (1)

[Claims] 1. A method for manufacturing a transfer foil comprising the following steps. 1. A process of printing and forming a concealing layer and a pattern layer after applying a heat-sensitive adhesive to a printing base sheet having mold releasability. 2. Apply an ultraviolet curable paint to the surface of the sheet obtained in (1), and then apply a transparent polyethylene terephthalate film on the surface of which a patterned varnish layer with one or more different varnishes has been formed in advance. A process of coating the pattern layer facing downward and irradiating ultraviolet rays from above to harden the paint. 3. Peeling and removing the printed base sheet having releasable properties.