JPS61291198A - Heat-sensitive transfer sheet and heat-sensitive transfer method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a novel heat-sensitive transfer sheet and a heat-sensitive transfer method. The present invention relates to an inexpensive thermal transfer sheet for application by a thermal transfer method and a thermal transfer method.

(Prior Art) Heat-sensitive transfer sheets for imparting various designs to various articles by a heat-sensitive transfer method are conventionally known. These heat-sensitive transfer sheets are generally made by forming a release layer on the entire surface of a base sheet, forming a desired pattern layer thereon, and further forming a heat-sensitive adhesive layer on the entire surface. .

- I - Heat-sensitive heat-sensitive transfer sheets The material to which images are applied is often opaque paper, but in recent years, in addition to paper, molded products such as various transparent plastic sheets are also being transferred. It has come to be used as a material.

(Problem to be solved by the invention) When a pattern layer is transferred to an opaque transfer material such as paper, the surface of the pattern layer on the opposite side from that on a heat-sensitive transfer sheet is visible, and on the other hand, the surface of the pattern layer is transparent. In the case of a transparent transfer material such as a plastic sheet, the pattern can be seen through the transparent plastic sheet, so the pattern can be seen on the same side as on the heat-sensitive transfer sheet used for transfer.

Therefore, when the image is transferred to a transparent transfer material using a conventionally known heat-sensitive transfer sheet, the pattern is seen through the transparent transfer material and the heat-sensitive adhesive layer, resulting in a problem that the image appears unclear.

In addition, in conventional heat-sensitive transfer sheets, even if the pattern is not formed on the entire surface of the base sheet, the heat-sensitive adhesive layer is formed on the entire surface, so when transferred to a transparent transfer material in the same way as above, A problem arises in that the heat-sensitive adhesive layer is transferred even in areas where there is no pattern, thereby reducing the transparency of the transparent transfer material.

Furthermore, as in 5 above, since the release layer is also generally formed on the entire surface, there is a tendency for the transferred material to become further cloudy after transfer. In addition, in the conventional technology, the release layer also functions as a protective layer (overprint layer) for the transferred pattern, but in the case of a transparent transfer material, the transparent transfer material protects the transferred pattern. This is unnecessary since it acts as a sufficient protective layer.

As a result of intensive research in order to solve the problems of the prior art as described in -1-, the present inventor used a releasable material as a base sheet of a heat-sensitive transfer sheet, and further developed an ink coating for forming a pattern. The present invention was developed based on the finding that by using a specific material as a forming component, the problems of the prior art described above can be solved and a heat-sensitive transfer sheet capable of imparting an excellent transferred pattern to a transparent transfer material can be obtained. completed.

(Means for Solving the Problems) That is, the present invention consists of a base sheet and a pattern layer provided on one side of the base sheet, and the film-forming component of the pattern layer is bonded by heating. The present invention relates to a heat-sensitive transfer sheet characterized in that it is made of a natural or synthetic resin exhibiting properties, and a heat-sensitive transfer method using the heat-sensitive transfer sheet.

Next, the present invention will be further described with reference to the accompanying drawings that schematically illustrate preferred embodiments of the heat-sensitive transfer sheet of the present invention and its method of use.

FIG. 1 of the accompanying drawings schematically shows a cross section of the heat-sensitive transfer sheet of the present invention, and FIG. 2 schematically shows a method of transferring onto a transparent transfer material using the heat-sensitive transfer sheet of the present invention. This is shown below.

Referring to FIG. 1, the thermal transfer sheet of the present invention basically consists of a base sheet 1 and a pattern layer 2 formed on the surface of the base sheet 1. Any known material may be used as long as the surface thereof has a releasability to the extent that it can be easily peeled off from the pattern layer 2 on the surface, such as polyethylene terephthalate, polypropylene, polyethylene, polyamide, etc. plastic films such as, releasable films made by coating these films with a release agent, kraft paper, glassine paper, parchment paper laminated with films such as those mentioned above, and silicone treatment of these films and papers. You can use any one that has been treated with. The thickness of such a base sheet 1 is not particularly limited as long as it has appropriate strength and sufficient heat resistance against heat during transfer.

The pattern layer 2 provided on the base sheet described in -1- contains coloring agents such as dyes and pigments, film-forming components for forming the pattern layer after drying, organic solvents added as necessary, and other additives. It is formed using printing ink made of a chemical agent.

The pattern layer of a conventionally known heat-sensitive transfer sheet is generally made of natural or organic material having heat crosslinkability, room temperature crosslinkability, etc., in order to impart various strengths such as abrasion resistance, chemical resistance, heat resistance, etc. after transfer. Synthetic resins have been widely used as film-forming components.

In the present invention, unlike conventional film-forming components, the film-forming component of the printing ink softens when heated and exhibits adhesive properties to the transferred material, and when cooled, the bonded portion solidifies. The main feature is that it uses a natural or synthetic resin that retains its adhesive strength while solidifying and losing its adhesive properties in the non-adhered parts.

Such heat-sensitive adhesives are used in conventional heat-sensitive transfer sheets to adhere the pattern layer to the transfer material, and such conventionally known heat-sensitive adhesives are used in the printing ink used in the present invention. Any of these can be used as a film-forming component, specifically, for example, rubber resins such as polyimprene rubber, polyisobutyl rubber, styrene-butadiene rubber, butadiene-acrylonitrile rubber,
(Meth)acrylic acid ester resin, polyvinyl ether resin, polyvinyl acetate resin, vinyl chloride vinyl acetate copolymer resin, polystyrene resin, polyester resin, polyamide resin, polybalanced olefin resin, polyvinyl Any film-forming component such as butyral resin, cellulose resin, etc. can be used, and various additives such as a softener, a filler, and an anti-aging agent can also be added, if necessary. All of these film-forming components are commercially available and can be easily used.

In the present invention, such a film-forming component does not necessarily have to be reversibly thermoplastic, and may be one that exhibits adhesive properties during transfer, even if it causes a certain degree of crosslinking reaction during transfer. Of course.

The printing ink used to form the heat-sensitive transfer sheet of the present invention uses conventionally known techniques as is, except that the film-forming component has heat-sensitive adhesive properties as described above. By using various components and selecting combinations, it can be used as gravure printing ink, silk screen printing ink, gravure offset printing ink, offset printing ink, flexographic printing ink, etc. Particularly suitable inks are silk screen printing inks.

Formation of the pattern layer 2 using such printing ink can be performed by conventionally known methods such as gravure printing, silk screen printing, gravure offset printing, offset printing, and flexographic printing. Particularly preferred is silk screen printing. The pattern layer 2 formed with such ink may have any pattern, but its thickness is preferably about 1 to Fop-m.

The method of transferring the pattern layer 2 to various transfer materials, preferably transparent transfer material 3 using the heat-sensitive transfer sheet of the present invention as described above may be in accordance with conventionally known methods. As shown in the figure, a heat-sensitive transfer sheet is placed on a transparent transfer material 3, and a film-forming component forming a pattern layer 2 is applied from one or both sides using, for example, a heating roll 4 or other heating press machine (not shown). The pattern layer 2 can be transferred to the transparent transfer material 3 by heating and pressurizing it to a temperature at which it softens and exhibits adhesive properties, for example, about 150 to 230° C., and then peeling off the base sheet 1.

As the transfer material used in the method of the present invention, it is of course possible to use transfer materials used in conventionally known thermal transfer methods, such as paper, metal, wood, and other opaque transfer materials, but the advantages of the heat-sensitive transfer sheet of the present invention are as follows. The most effective effect is on transparent transfer materials such as Homei plastic sheets and transparent glass, and especially when transferring to the back side of these transparent molded products,
It is ideal for observing the transferred pattern layer through a transparent sheet. However, since such transparent molded products are generally made of plastic, the adhesiveness of the pattern layer to the transfer material and the base sheet is greater than the adhesion to the transfer material. 1. It is necessary to select the film-forming component and transfer material that constitute the pattern layer 2.

(Function/Effect) According to the heat-sensitive transfer sheet of the present invention and the heat-sensitive transfer method of the present invention as described above, especially when a transparent transfer material such as a transparent sheet is selected as the transfer material, the transfer material and the Since there is no adhesive layer between the thermal transfer sheet and the original material that causes turbidity as in the prior art, a clear transferred pattern without turbidity can be formed. In addition, the heat-sensitive transfer sheet of the present invention does not contain any material that may impair the transparency of the transparent transfer material.
.

Furthermore, since no peeling layer is formed as in the prior art, the transparency of the transparent material to be transferred is not impaired.

Therefore, according to the present invention, higher quality transfer products can be provided at a lower cost than in the prior art.

Next, the present invention will be explained in more detail with reference to Examples. It should be noted that the terms in the text or % are based on weight unless otherwise specified.

Example 1 On one side of a polyethylene terephthalate film with a thickness of 50 pLm as a base sheet, a pattern with a thickness of about 9 gm was printed using four colors of silk screen printing ink of the following composition by a silk screen method, and the pattern according to the present invention was printed using a silk screen method. A thermal transfer sheet was obtained.

Industrial Z clay 1 piece pigment
20 parts Film-forming component (vinyl chloride/vinyl acetate copolymer) 500 parts solvent (isophorone) 29 parts additive (silicone antifoaming agent) 1 part Activity 4.5
00cps The thermal transfer sheet of the above-mentioned wooden invention was placed on the back side of a 1mm thick sheet made of polymethyl methacrylate, and
Transfer was performed continuously using a roll transfer machine (C).

The transferred image obtained by this process can be observed through the sheet and has an extremely clear image, and the untransferred portion of the image layer has the same high transparency as the original polymethyl methacrylate. had.

Example 2 A pattern was printed on one side of a polyethylene terephthalate film having a thickness of 25 gm as a base sheet using four colors of gravure printing inks having the following composition to obtain a heat-sensitive transfer sheet of the present invention.

soil Z soil 1 Makoto color fee
15 parts Film-forming component (methyl methacrylate/butyl methacrylate copolymer resin) 400 parts Solvent (methyl ethyl ketone/ethyl acetate - 1/l) 44 parts Additives (
Silica-based matting agent), 1 part activity
200 cpS The above heat-sensitive transfer sheet of the present invention was placed on the back side of a transparent plate material made of polystyrene resin, and transfer was performed using a roll transfer machine at 200°C.

The pattern of the obtained transfer product had excellent transparency.

Comparative Example A release layer and a pattern layer (thickness: 3 m) were applied to one side of a polyethylene terephthalate film having a thickness of 25 pLm and 38 parts m as a base sheet using each ink having the following composition.
, heat-sensitive adhesive layers were sequentially provided by gravure printing, Example 1
When the transfer material was transferred to the same transfer material as in Example 2, it was found that in this comparative example, both in the areas where the pattern was not transferred and in the areas where the pattern was transferred, the application opening of the release layer and the heat-sensitive adhesive layer was Particularly in the area where the pattern was transferred, the pattern was observed to become cloudy, and a good appearance could not be obtained.

Ink methyl methacrylate resin 40 parts extender pigment (
microsilica) 2 parts Organic solvent (ethyl acetate/toluene = 1/l) 58 parts (coating film thickness
approx. IILm) Ink pigment
20 parts Methyl methacrylate resin 400 parts Solvent (ethyl acetate/toluene = 1/1) 40 parts (film thickness
3 pLm) W Ink Butyl methacrylate resin 30 parts Extender pigment (
Microsilica) 3 parts Organic solvent (ethyl acetate/toluene = 1/1) 67 parts (film thickness approximately 0.5 pLm)

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing a cross section of a heat-sensitive transfer sheet of the present invention, and FIG. 2 is a diagram schematically showing a heat-sensitive transfer method of the present invention. 1: Base sheet 2; Pattern layer 3; Transfer material 4; Roll Figure 1 Figure 2

Claims (2)

[Claims] (1) It consists of a base sheet and a pattern layer provided on one side of the base sheet, and the film-forming component of the pattern layer is made of a natural or synthetic resin that exhibits adhesive properties when heated. Thermal transfer sheet. (2) A thermal transfer sheet consisting of a base sheet and a pattern layer provided on one side of the base sheet, in which the film-forming component of the pattern layer is made of a natural or synthetic resin that exhibits adhesive properties when heated. A thermal transfer method to a transparent transfer material, characterized by polymerizing and thermally transferring to the transparent transfer material.