JP2001047750A - Heat-transfer receiving sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a receiving sheet, which is suitable for a thermal printer, especially for a dye heat-transfer printer, and is excellent in the light-resistance and the grease-resistance of recorded images by containing at least a polyvinyl butyral resin and an epoxy resin in a receiving layer, which is provided at least on one surface of a sheet-form supporting body. SOLUTION: In a receiving layer, which is provided at least on one surface of a sheet-form supporting body, at least a polyvinyl butyral resin and an epoxy resin are contained. In this case, as the epoxy resin, at least one kind selected from BPA type epoxy resins having bisphenol A as the principal skeleton, and a hydrogenation BPA type epoxy resins having a hydrogenation type bisphenol A as the principal skeleton is contained. Then, the epoxy resin is blended by 5 to 80 pts.wt. based on 100 pts.wt. of the polyvinyl butyral resin, preferably by 10 to 50 pts.wt. By this constitution, the light-resistance and the grease-resistance of images are improved, and a receiving sheet, which can perform a full color printing of a heat-transfer method, is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer receiving sheet. More specifically, the present invention relates to a heat transfer receiving sheet having excellent light resistance of a recorded image and excellent oil resistance.

[0002]

2. Description of the Related Art In a dye thermal transfer printer, a receiving layer of a thermal transfer receiving sheet (hereinafter simply referred to as a receiving sheet) is superimposed on a dye ink sheet, and the dye is transferred onto the receiving layer by heat supplied from a thermal head or the like. The image is formed by transfer. In the case of the dye thermal transfer system, a dye-dyeable resin is used as the receptor layer, and thermoplastic resins such as cellulose acetate butyrate, polyvinyl butyral, and polyester resin have been proposed.

[0003]

The dye thermal transfer system is capable of recording high-quality images, and is being replaced by silver halide photography. However, if the image obtained by the dye thermal transfer method is used for the same purpose as silver halide photography, the stability of the image to light (light fastness) and the chance of being touched directly by human hands will increase, and the stability to human fat will increase. (Grease resistance) has become particularly required. In general, when a polyester resin is used as the dye-dyeing resin of the receptor layer, only a resin having excellent light resistance but poor light resistance can be obtained. In addition, it is known that when a cellulose acetate butyrate resin, a polyvinyl butyral resin, or the like is used as a dye-dyeing resin for the receptor layer, the image has excellent light fastness (Japanese Patent Application Laid-Open No. 61-11293).
However, these resins are inferior in grease resistance.

[0004] In order to improve the light resistance and the grease resistance, a method of transferring an over-laminate layer after recording an image has been proposed, but it is not preferable because the printing time becomes longer and the running cost of the printing increases. The present invention relates to a receiving sheet which is suitable for a thermal printer, in particular, a dye thermal transfer printer, and has excellent light resistance and grease resistance of a recorded image.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that the present invention can be achieved by using at least a polyvinyl butyral resin and an epoxy resin in combination as a receiving layer. .
The present invention provides a thermal transfer receiving sheet having a sheet-like support and a receiving layer on at least one surface of the sheet-like support, wherein the receiving layer contains at least a polyvinyl butyral resin and an epoxy resin. is there.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a thermal transfer receiving sheet in which a receiving layer is laminated on a sheet-like support, wherein the receiving layer is a layer in which at least a polyvinyl butyral resin and an epoxy resin are used in combination. Among the epoxy resins, epoxy resins having bisphenol A as a main skeleton (hereinafter also referred to as BPA type epoxy resin) and epoxy resins having hydrogenated bisphenol A as a main skeleton (hereinafter also referred to as hydrogenated BPA type epoxy resin) are used. It is more preferable to include at least one selected from the group because both light resistance and grease resistance are excellent. In addition, comparing the BPA type epoxy resin and the hydrogenated BPA type epoxy resin, the combined use of the BPA type epoxy resin tends to have particularly excellent oil resistance, and the combined use of the hydrogenated BPA type epoxy resin tends to have particularly excellent light resistance. .

The image obtained by the dye thermal transfer system is severely faded by light. This is presumably because the dye and the thermoplastic resin are deteriorated under the influence of ultraviolet rays (290 to 400 nm) contained in sunlight or the like. When polyester, polyurethane, polycarbonate, or the like having a functional group that absorbs light in this region in the polymer skeleton is used as the thermoplastic resin, image fading is particularly severe. On the other hand, the light resistance of the dye receiving layer using cellulose acetate butyrate resin or polyvinyl butyral resin is less fading than the above-mentioned resins, but is poor in grease resistance, so that fading easily occurs with human fat and the like, and there is a practical problem. was there. The present inventors have conducted intensive studies and have found that, in particular, polyvinyl butyral resin and epoxy resin, especially BPA
It has been found that these weaknesses can be overcome by using a type epoxy resin or a hydrogenated BPA type epoxy resin in combination.

In the present invention, the polyvinyl butyral resin used in the receiving layer is not particularly limited in the production method, but is generally produced by reacting polyvinyl alcohol with butyraldehyde, and the degree of substitution is appropriately adjusted. In the form of a copolymer of vinyl butyral and vinyl alcohol. At that time, the degree of butyralization is 60
It is preferable to adjust the amount in the range of from about 80 mol% to the point that the dyeing property of the dye is excellent. In addition, it is preferable that unsaponified vinyl acetate groups caused by polyvinyl alcohol as a raw material be suppressed to 20% or less, more preferably 10% or less. Although the degree of polymerization is not particularly limited,
Or less, preferably 1000 or less. Further, the glass transition temperature (Tg) of the resin is 50 ° C to 100 ° C.
° C, preferably 50 ° C to 80 ° C.

The BPA type epoxy resin referred to in the present invention has a structure represented by the following chemical formula 1.

[0010]

Embedded image

(Where n is 3 or more)

The hydrogenated BPA type epoxy resin according to the present invention has a structure represented by the following chemical formula 2.

[0013]

Embedded image

(Where n is 3 or more)

When a BPA type epoxy resin is used as a resin for a receiving sheet, a dye receiving layer having excellent oil resistance can be obtained, but on the other hand, it is difficult to use a BPA type epoxy resin alone because it has poor blocking and poor fusion and light resistance of a ribbon. Have difficulty. But,
It has been found that when used in combination with a polyvinyl butyral resin, grease resistance can be significantly improved. In addition, hydrogenated BPA
The light resistance is further improved by using the type epoxy resin.

These epoxy resins can be blended in an amount of 5 to 80 parts by weight, preferably 10 to 50 parts by weight, based on 100 parts by weight of polyvinyl butyral. When the amount is less than 5 parts by weight, there is no effect of improving the oil resistance, and when the amount is more than 80 parts by weight, the light resistance is inferior, and the ribbon fusion and blocking during printing are liable to occur. The molecular weight of these epoxy resins is preferably from 1,000 to 20,000. When the molecular weight is less than 1,000, fusion with a ribbon or the like during printing tends to occur. On the other hand, if the molecular weight is large, the compatibility with the polyvinyl butyral resin in forming the coating liquid for the receiving layer is inferior, so that the molecular weight is preferably 20,000 or less, more preferably 10,000 or less.

In the receiving layer, polyvinyl butyral resin,
In addition to the BPA type epoxy resin and the hydrogenated BPA type epoxy resin, a known thermoplastic resin can be used in combination as long as the effects of the present invention are not impaired. For example, polyvinyl chloride, polyvinyl butyral, polyacetal, polyvinylidene chloride, polyvinyl acetate, polyvinyl formal, polystyrene, styrene / acrylonitrile copolymer, polyethylene, ethylene / vinyl acetate copolymer, polypropylene, polyacetal, polymethyl methacrylate, MM
One or more of A / styrene copolymer, polyamide, ethyl cellulose, cellulose acetate, propyl cellulose, acetic acid / butyrate, cellulose nitrate, polycarbonate, phenoxy, polyester, polyurethane and the like can be used in combination.

In order to further improve the light resistance, an ultraviolet absorber or a hindered amine light stabilizer may be used alone or in combination in the receiving layer.

As the ultraviolet absorber, benzotriazole-based ultraviolet absorbers, triazine-based ultraviolet absorbers, oxalic anilide-based ultraviolet absorbers, and benzophenone-based ultraviolet absorbers are generally known, and any of them can be used.
Benzotriazole ultraviolet absorbers are particularly preferred because they have a wider absorption wavelength, a maximum absorption peak on the higher wavelength side, and a higher absorbance than others. In addition, a benzotriazole-based ultraviolet absorber is preferably used because the best effect is obtained when used in combination with a hindered amine-based light stabilizer. UV absorber is thermoplastic resin 1
About 1 to 70 parts by weight can be blended with respect to 00 parts, and in particular, from 1 to 40 parts by weight is preferably used in consideration of the amount of the ultraviolet absorbent to be added and the effect.

The hindered amine light stabilizers are 2,2
It is a compound having a 2,6,6-tetramethylpiperezin skeleton, and is not particularly limited as long as it has this skeleton. The hindered amine light stabilizer can be blended in an amount of about 1 to 70 parts by weight, based on 100 parts of the thermoplastic resin. In particular, from 1 to 40 parts by weight, depending on the amount of the hindered amine light stabilizer and the effect. It is preferably used.

The receiving layer may also contain a crosslinking agent and an anti-fusing agent, and it is preferable that these receiving layer components cause a crosslinking reaction via the crosslinking agent. The coating amount of the receiving layer is 0.1 to
It is desirable to be in the range of 20.0 g / m ² .

As the sheet-like support of the receiving sheet, a known substrate can be used, and examples thereof include paper, film, and a laminated substrate thereof. As paper, paper containing cellulose pulp as a main component, coated paper, art paper, cast coated paper, laminated paper provided with a thermoplastic resin layer on at least one surface, and films such as polyester, polyamide, polyolefin, polystyrene, Films such as polycarbonate, polyvinyl alcohol, and polyvinyl chloride are used. Further, a film having a plurality of layers, a film in which the inside of the film is foamed, a film in which microvoids are formed by stretching (for example, synthetic paper), and the like can be used. As the laminated base material, a laminated substrate of two or more sheets can be used. For example, a laminated substrate on one side or both sides such as paper or polyester film can be used.

The laminating method is not particularly limited, but a known technique such as wet lamination, extrusion lamination, dry lamination or wax lamination may be used, and a dry lamination method is generally used. As the dry laminating adhesive, an adhesive of a polyether type, a polyester type or the like can be used. Moreover, the laminated material obtained by the present invention is 20 to 20.
It is desirable to have a thickness of 300 μm.

In the receiving sheet of the present invention, the running performance is improved, the static electricity is prevented,
A back coating layer is formed for the purpose of preventing damage to the image receiving layer due to rubbing between the receiving sheets, and further preventing transfer of dye from the receiving layer to the back side of the adjacent receiving sheet when the printed receiving sheets are stacked. May be. The back cover layer contains a resin effective as an adhesive, and this resin is also effective for preventing the running of the receiving sheet and preventing the receiving layer surface from being damaged. Such resins include acrylic resins, epoxy resins, polyester resins, phenolic resins, alkyd resins, urethane resins,
Melamine resins and the like, and reaction cured products of these resins can be used.

Various conductive agents can be added to the back cover layer for antistatic treatment. It is desirable to use a cationic polymer as the conductive agent.
As the cationic polymer, generally, polyethyleneimine, an acrylic polymer containing a cationic monomer, a cation-modified acrylamide polymer, a cationic starch and the like can be used. Further, the back cover layer may appropriately contain a known lubricant such as a higher fatty acid salt, an organic pigment, an inorganic pigment, a release agent, a crosslinking agent, and the like. In addition,
The coating amount of the back cover layer is desirably in the range of 0.3 to 10.0 g / m ² .

Each of these coating layers can be formed by applying and drying using a coater such as a gravure coater, a blade coater, an air knife coater, and a gate roll coater.

The form of use of the receiving sheet of the present invention is not particularly limited, and can be used as a substitute for a silver halide photograph.
Labels, stamps, magnetic cards,
By arranging it on the surface of a card base such as an IC card, it can be used for applications such as credit cards, prepaid cards, commuter passes, boarding tickets, business cards, and the like.

[0028]

The present invention will be described in more detail with reference to the following examples, which, of course, are not intended to limit the scope of the present invention. In the examples, "parts" and "%" all indicate "parts by weight" and "% by weight".

Example 1 A biaxially stretched polypropylene-based multilayer structure film (trade name: YUPO FPG50, manufactured by Oji Yuka Synthetic Paper) was laminated on both sides of a high-quality paper having a thickness of 100 μm by dry lamination. This was used as a substrate. Further, one of the substrates was coated with the following coating liquid for a receiving layer so that the coating amount of the solid content was 5 g / m ^2, and dried (120 ° C. for 1 minute) to form a receiving layer. Created a sheet. "Coating for receiving layer"-Polyvinyl butyral resin (trademark: Esrec BM-S, manufactured by Sekisui Chemical Co., Ltd.) 80 parts-Bisphenol A type epoxy resin (trademark: Epototo YD-014, manufactured by Toto Kasei Co., Ltd.) 20 parts-Silicone oil (Trademark: KF393, manufactured by Shin-Etsu Silicon Co., Ltd.) 3 parts ・ Isocyanate (trademark: Takenate D-140N, manufactured by Takeda Pharmaceutical Co., Ltd.) 5 parts ・ Toluene 300 parts

Example 2 A thermal transfer receiving sheet was obtained in the same manner as in Example 1 except that the following paint for a receiving layer was used. "Coating for receiving layer"-Polyvinyl butyral resin (trade name: Eslec BM-S, manufactured by Sekisui Chemical Co., Ltd.) 80 parts-Hydrogenated bisphenol A type epoxy resin (trade name: Santoto ST-5080, manufactured by Toto Kasei Co., Ltd.) 20 parts- Silicone oil (trademark: KF393, Shin-Etsu Silicone Co., Ltd.) 3 parts ・ Isocyanate (trademark: Takenate D-140N, Takeda Pharmaceutical Co., Ltd.) 5 parts ・ Toluene 300 parts

Comparative Example 1 A thermal transfer receiving sheet was obtained in the same manner as in Example 1 except that the following coating material for a receiving layer was used. "Coating for receiving layer"-100 parts of polyvinyl butyral resin (trademark: Esrec BMS, manufactured by Sekisui Chemical Co., Ltd.)-3 parts of silicone oil (trademark: KF393, manufactured by Shin-Etsu Silicon Co., Ltd.)-isocyanate (trademark: Takenate D-140N, Takeda) 5 parts ・ Toluene 300 parts

Comparative Example 2 A thermal transfer receiving sheet was obtained in the same manner as in Example 1 except that the following coating material for a receiving layer was used. "Coating for receiving layer" 100 parts bisphenol A epoxy resin (trademark: Epototo YD-014, manufactured by Toto Kasei Co., Ltd.) 3 parts silicone oil (trademark: KF393, manufactured by Shin-Etsu Silicon Co., Ltd.) 3 isocyanate (trademark: Takenate D- 140N, manufactured by Takeda Pharmaceutical) 5 parts ・ Toluene 300 parts

Comparative Example 3 A thermal transfer receiving sheet was obtained in the same manner as in Example 1 except that the following coating for a receiving layer was used. "Coating for receiving layer"-100 parts of polyester resin (trademark: Byron 200, manufactured by Toyobo)-3 parts of silicone oil (trademark: KF393, manufactured by Shin-Etsu Silicon Co.)-Isocyanate (trademark: Takenate D-140N, manufactured by Takeda Pharmaceutical Co., Ltd.) 5 parts ・ Toluene 300 parts

Evaluation Each of the obtained receiving sheets was printed, and the light resistance and the grease resistance of the image were evaluated. Table 1 shows the obtained results. [Print] The obtained receiving sheet was printed using a thermal transfer video printer (trade name: XLS-8400, manufactured by Kodak Co., Ltd.) to adjust the applied energy and print solid black with an OD = 1.0.

[Light Resistance Test] The printed sheet was treated with a xenon light resistance tester (trade name: Atlas Fade Meter).
For 72 hours, the solid black OD after the treatment was measured, and the residual ratio of the image was calculated according to the following equation. If the residual ratio in this compulsory test is 60% or more, it is considered that the light resistance level is practically acceptable. Image residual ratio (%) = OD after processing / OD before processing × 100

[Oil resistance test] 0.1 g of oleic acid was dropped on the printed sheet with a dropper, and after 10 minutes, oleic acid was wiped off with a waste cloth. The black solid OD after the treatment was measured, and the residual ratio of the image was calculated according to the following equation. If the residual ratio in this compulsory test is 60% or more, it is considered that the light resistance level is practically acceptable. Image residual ratio (%) = OD after processing / OD before processing × 100

[0037]

[Table 1]

In Comparative Example 1, polyvinyl butyral was used alone as the resin for the receiving layer. However, although the light resistance of the image was excellent, the oil resistance did not reach a practical level. In Comparative Example 2, although the BPA type epoxy resin was used alone as the receiving layer resin alone, the light resistance did not reach a practical level although the oil resistance was excellent. In contrast, Example 1
Is a combination of BPA-type epoxy resin, but inherits the excellent light resistance of polyvinyl butyral resin and the excellent oil resistance of BPA-type epoxy resin, resulting in a well-balanced receiving layer. Further, in Example 2, hydrogenated BPA
However, the light resistance is improved as compared with the first embodiment.

[0039]

According to the present invention, there is provided a receiving sheet which is excellent in light fastness of an image and is excellent in grease resistance and which can be used for full-color printing of a thermal transfer system such as a sublimation thermal transfer system. The contribution to the industry is great.

Claims (3)

[Claims] 1. A thermal transfer receiving sheet having a sheet-like support and a receiving layer on at least one surface of the sheet-like support, wherein the receiving layer contains at least a polyvinyl butyral resin and an epoxy resin. . 2. The thermal transfer receiving sheet according to claim 1, wherein the epoxy resin is at least one selected from an epoxy resin having bisphenol A as a main skeleton and an epoxy resin having hydrogenated bisphenol A as a main skeleton. 3. The thermal transfer receiving sheet according to claim 1, wherein the receiving layer is formed with an epoxy resin in an amount of 5 to 80 parts by weight based on 100 parts by weight of the polyvinyl butyral resin.