JPH068646A - Thermal transfer image receiving sheet - Google Patents

Abstract

PURPOSE:To provide a thermal transfer image receiving sheet excellent in the releasability from a thermal transfer sheet at the time of the formation of an image and capable of forming a recording image excellent in developed color density, sharpness and various durabilities in a thermal transfer method using a sublimable dye. CONSTITUTION:In a thermal transfer image receiving sheet constituted by forming a dye receiving layer on at least one surface of a base sheet, the dye receiving layer contains a crosslinked substance consisting of a hydroxyl group- containing thermoplastic resin and a crosslinking agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer image-receiving sheet, and more particularly to forming a recorded image having excellent releasability from the thermal transfer sheet at the time of image formation and excellent color density, sharpness and various durability. The object is to provide a thermal transfer image-receiving sheet capable of performing the above.

[0002]

2. Description of the Related Art Conventionally, various thermal transfer methods are known. Among them, a sublimable dye is used as a recording agent, and a sublimable dye is used as a thermal transfer sheet by supporting it on a base material sheet such as polyester film. Transferable material that can be dyed, for example,
There has been proposed a method of forming various full-color images on an image receiving sheet having a dye receiving layer formed on paper, a plastic film or the like. In this case, the thermal head of the printer is used as the heating means, and a large number of three-color or four-color dots are transferred to the image receiving sheet by heating for an extremely short time, and the full-color image of the original is formed by the multicolor dots. It is to be reproduced. The image formed in this way is extremely clear because the coloring material used is a dye and has excellent transparency, so the resulting image has excellent reproducibility and gradation of intermediate colors, and It is possible to form a high quality image which is similar to the image by offset printing or gravure printing and which is comparable to a full color photographic image.

[0003]

In order to effectively carry out the above-mentioned thermal transfer method, not only the structure of the thermal transfer sheet but also the structure of the image receiving sheet for forming an image are important. As a conventional technique of the thermal transfer image-receiving sheet, for example, JP-A-57-169370 and 57-20725 can be used.
No. 0, No. 60-25793, etc., polyester resins, vinyl resins such as polyvinyl chloride resins, polycarbonate resins, polyvinyl butyral resins, acrylic resins, cellulose resins, olefin resins,
A resin in which a dye receiving layer is formed using a polystyrene resin or the like is disclosed.

In the thermal transfer image-receiving sheet as described above, as a means for improving the dyeing property of the dye to be transferred, a dye receiving layer is formed from a resin having good dyeing property, or a plasticizer is contained in the receiving layer. It may be contained to improve the diffusibility of the dye at the time of thermal transfer.However, since the dye receiving layer made of a resin having a good dye dyeing property has a low softening point of the receiving layer, There is a problem of so-called abnormal transfer in which a large peeling noise is generated at the time of peeling, and the dye layer is transferred layer by layer due to fusion due to heat from the thermal head during formation. Furthermore, the formed image bleeds during storage, resulting in poor image storability.
There is a problem that the dye easily bleeds out to the surface and contaminates other articles that come into contact with the surface. Further, in the high density area, the dye receiving layer is embossed by the printing pressure of the thermal head, so that the high gloss area has a high gloss, especially OH.
In P application, there is a problem that a transparent image cannot be obtained. As a method for solving the above-mentioned problems such as releasability, storability, stain resistance, and embossing, a resin in which the dyed dye is difficult to migrate in the dye receiving layer may be selected. However, there is a problem in that it is not possible to form an image having high density and high sharpness. Therefore, an object of the present invention is to provide a recorded image excellent in releasability from a thermal transfer sheet at the time of image formation and excellent in color density, sharpness, various durability and non-embossing property in a thermal transfer method using a sublimable dye. A thermal transfer image-receiving sheet that can be formed.

[0005]

The above object can be achieved by the present invention described below. That is, the present invention is a thermal transfer image-receiving sheet formed by forming a dye receiving layer on at least one surface of a substrate sheet, wherein the dye receiving layer contains a crosslinked product composed of a hydroxyl group-containing thermoplastic resin and a crosslinking agent. A thermal transfer image-receiving sheet characterized by the above.

[0006]

[Function] By incorporating a cross-linked product of a hydroxyl group-containing thermoplastic resin and a cross-linking agent in the dye-receiving layer, excellent releasability from the thermal transfer sheet during image formation, color density, sharpness and various durability Further, it is possible to provide a thermal transfer image-receiving sheet capable of forming a recorded image excellent in non-embossing property.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to preferred embodiments. The thermal transfer image-receiving sheet of the present invention comprises a dye receiving layer provided on at least one surface of a substrate sheet. The base sheet used in the present invention,
Synthetic paper (polyolefin-based, polystyrene-based, etc.), high-quality paper, art paper, coated paper, cast-coated paper, wallpaper, backing paper, synthetic resin or emulsion-impregnated paper, synthetic rubber latex-impregnated paper, synthetic resin internal-added paper, paperboard, etc. Films or sheets of various plastics such as, cellulose fiber paper, polyolefin, polyvinyl chloride, polyethylene terephthalate, polystyrene, polymethacrylate, polycarbonate, etc. can be used, and white pigments and fillers are added to these synthetic resins. A white opaque film that has been formed into a film or a foamed sheet that has been foamed can also be used and is not particularly limited. Further, a laminated body made of any combination of the above-mentioned substrate sheets can also be used. As an example of a typical laminated body, there is a synthetic paper of cellulose fiber paper and synthetic paper or cellulose fiber paper and plastic film or sheet. The thickness of these base material sheets may be arbitrary, and for example, a thickness of about 10 to 300 μm is common. The substrate sheet as described above is preferably subjected to a primer treatment or a corona discharge treatment on the surface when the adhesion to the receiving layer formed on the surface is poor.

The receiving layer formed on the surface of the base sheet is for receiving the sublimable dye transferred from the thermal transfer sheet and maintaining the formed image. The dye-receptive layer, which is a main feature of the present invention, is formed by containing a crosslinked product composed of a hydroxyl group-containing thermoplastic resin and a crosslinking agent. The hydroxyl group-containing thermoplastic resin used in the present invention is polyester, partially saponified polyvinyl acetate, vinyl chloride-partially or completely saponified product of vinyl acetate copolymer, acrylic resin,
Any hydroxyl group-containing thermoplastic resin such as polyurethane resin may be used, but particularly suitable materials are polyvinyl acetal resin and vinyl chloride-vinyl acetate copolymer, and polyvinyl acetal resin reacts various aldehydes on the hydroxyl group of polyvinyl alcohol. It is a general term for the resins obtained as described above, and various ones can be used in the present invention.
Preferred polyvinyl acetal resins are polyvinyl formal resins, polyvinyl acetoacetal resins and polyvinyl butyral resins. The polyvinyl alcohol unit in the polyvinyl acetal resin is 10% by weight or more,
The amount is preferably in the range of 5 to 30% by weight, and such an amount can be easily adjusted by adjusting the reaction amount of the aldehyde used when acetalizing polyvinyl alcohol. When the polyvinyl alcohol unit is less than 10% by weight, the image of high peeling property, high density and high durability which is the object of the present invention is not formed, while 5
When it exceeds 0% by weight, the dyeing property of the dye and the water resistance of the dye receiving layer are deteriorated, which is not preferable. The molecular weight of the polyvinyl acetal resin is not particularly limited, but the degree of polymerization is preferably in the range of 100 to 10,000.

Further, a preferred vinyl chloride-vinyl acetate copolymer has a polyvinyl alcohol unit content of 1 to
The content is in the range of 30% by weight, and the range can be adjusted easily by adjusting the copolymerization ratio of vinyl acetate and the saponification rate thereof. When the polyvinyl alcohol unit is less than 1% by weight, the image of high peelability, high density and high durability which is the object of the present invention is not formed. On the other hand, when it exceeds 30% by weight, the dyeing property of the dye or the It is not preferable because the water resistance of the dye receiving layer is lowered. The molecular weight of the vinyl chloride-vinyl acetate copolymer is not particularly limited, but the degree of polymerization is preferably in the range of 200 to 500. The crosslinking agent used in the present invention is a compound having at least two functional groups capable of reacting with a hydroxyl group, and examples thereof include phenol resin, epoxy resin, melamine resin, urea resin, alkyd resin, ester gum, nitrocellulose, and chelate. Examples thereof include compounds and polyisocyanate compounds, and polyisocyanate compounds and chelate compounds are particularly preferable. The amount of the cross-linking agent is not specified unconditionally depending on the type of the above-mentioned hydroxyl group-containing thermoplastic resin, the number of functional groups, the molecular weight of the cross-linking agent and the number of functional groups, but is generally such that the thermoplastic resin loses its thermoplasticity. Amount of crosslinker, eg, 1 per 100 parts by weight of thermoplastic resin
It is about 200% by weight.

In the present invention, it is preferable to use a thermoplastic resin having a good dye-dyeability in addition to the above-mentioned cross-linked product. For example, a polyolefin resin such as polypropylene, a halogen such as polyvinyl chloride or polyvinylidene chloride. Copolymers, vinyl polymers such as polyvinyl acetate and polyacrylic ester, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polystyrene resins, polyamide resins, copolymerization of olefins such as ethylene and propylene with other vinyl monomers. System resin,
Ionomer, cellulosic resin such as cellulose diacetate, and polycarbonate may be used in combination.
The range of 10 to 90% by weight of the dye-receptive layer is preferable for these dye-dyeing resins, and if it is less than 10% by weight, the high-concentration image which is the object of the present invention cannot be achieved. If it exceeds 90% by weight, the releasability becomes insufficient, which is not preferable.

The thermal transfer image-receiving sheet of the present invention has a hydroxyl group-containing thermoplastic resin, a cross-linking agent, a dye-dyeing resin and other necessary additives, such as those described above, on at least one surface of the above-mentioned substrate sheet. A release agent, a catalyst, a thermal release agent, an ultraviolet absorber, an antioxidant, a light stabilizer and the like are added, dissolved in a suitable organic solvent or dispersed in an organic solvent or water, for example, , A gravure printing method, a screen printing method, a reverse roll coating method using a gravure plate, and the like.

Preferred releasing agents to be mixed with the above resins include silicone oils, phosphate ester type surfactants, fluorine type surfactants and the like, but silicone oils are preferable. As the silicone oil, modified silicone oil such as epoxy modified, alkyl modified, amino modified, carboxyl modified, alcohol modified, fluorine modified, alkylaralkyl polyether modified, epoxy / polyether modified or polyether modified is desirable. As the release agent, one type or two or more types are used. or,
The amount of the release agent added is preferably 0.5 to 30 parts by weight with respect to 100 parts by weight of the dye receiving layer forming resin. If the addition amount range is not satisfied, problems such as fusion of the thermal transfer sheet and the dye receiving layer or reduction of printing sensitivity may occur. By adding such a releasing agent to the dye receiving layer, the releasing agent bleeds out on the surface of the receiving layer after transfer to form a releasing layer.

The dye-receptive layer formed as described above may have any thickness, but it is generally from 1 to 50 μm.
Further, such a dye receiving layer is preferably a continuous coating, but it may be formed as a discontinuous coating by using a resin emulsion or a resin dispersion. In forming the above-mentioned receiving layer, pigments or fillers such as titanium oxide, zinc oxide, kaolin clay, calcium carbonate, fine powder silica and the like are used for the purpose of improving the whiteness of the receiving layer and further enhancing the sharpness of the transferred image. It can be added. The dye receiving layer formed as described above may have any thickness, but it is generally 1 to 50 μm thick. Further, such a dye receiving layer is preferably a continuous coating, but it may be formed as a discontinuous coating by using a resin emulsion or a resin dispersion.

In the present invention, the dye receiving layer can be formed by a transfer method. That is, for example, when pulp paper or the like is used as the base material sheet, the base material may lack surface smoothness. In this case, the dye receiving layer formed by the above coating method may have irregularities or unevenness. Although pinholes and the like may occur, such a problem does not occur according to the transfer method. For the transfer method, for example, the dye receiving layer is formed on the surface of a film having a good releasing property such as polyester film, and further an appropriate pressure-sensitive adhesive layer or adhesive layer is formed on the surface, and the pressure-sensitive adhesive layer is formed. Is opposed to the surface of the pulp paper base material and laminated with a laminator or the like, and then the polyester film is peeled off. When forming the intermediate layer, the intermediate layer may be previously formed on the surface of the pulp paper, or may be provided on the surface of the dye receiving layer of the receiving layer transfer sheet.

Further, the image-receiving sheet of the present invention can be applied to various applications such as a continuous sheet capable of thermal transfer recording, a sheet, a sheet of cards, a transmission type original preparation sheet, etc. by appropriately selecting a substrate sheet. You can also Further, the image-receiving sheet of the present invention can be provided with a cushion layer between the base sheet and the receiving layer, if necessary, and by providing such a cushion layer, there is little noise during printing and the image information can be dealt with. Images can be transferred and recorded with good reproducibility. The thermal transfer sheet used when performing thermal transfer using the thermal transfer image-receiving sheet of the present invention as described above is a paper or polyester film provided with a dye layer containing a sublimable dye, and a conventionally known thermal transfer sheet is Both can be used as they are in the present invention. As a means for applying heat energy during thermal transfer, any conventionally known applying means can be used, and for example, the recording time is controlled by a recording device such as a thermal printer (for example, video printer VY-100 manufactured by Hitachi, Ltd.). By doing,
By applying thermal energy of about 100 mJ / mm ² , the intended purpose can be sufficiently achieved.

[0016]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples. In the text, parts or% are based on the weight of the active ingredient unless otherwise specified. Example 1 Synthetic paper as a base material sheet (manufactured by Oji Yuka, Yupo FPG # 1)
50), a coating solution having the following composition was applied to one surface of the coating solution with a wire bar at a rate of 5.0 g / m ² when dried, and then heat-crosslinked and cured in an oven at 120 ° C for 3 minutes to form a book. A thermal transfer image-receiving sheet of the invention was obtained. Coating liquid composition; polyvinyl butyral resin (# 5000-A, manufactured by Denki Kagaku Kogyo) 0.50 part Isocyanate (Coronate 2030, manufactured by Nippon Polyurethane) 0.50 part Methyl ethyl ketone / toluene (weight ratio 1/1) 9.00 parts

Example 2 A thermal transfer image-receiving sheet of the present invention was obtained in the same manner as in Example 1 except that the following coating liquid was used in place of the coating liquid in Example 1. Coating liquid composition; polyvinyl butyral resin (# 5000-A, manufactured by Denki Kagaku Kogyo) 0.50 part Isocyanate (Coronate 2030, manufactured by Nippon Polyurethane) 0.50 part Amino-modified silicone (KF-393, manufactured by Shin-Etsu Chemical Co., Ltd.) 0 0.05 part Epoxy-modified silicone (X-22-343, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.05 part Methyl ethyl ketone / toluene (weight ratio 1/1) 9.00 parts Example 3 The following was used instead of the coating liquid in Example 1. The thermal transfer image-receiving sheet of the present invention was obtained in the same manner as in Example 1 except that the coating liquid of above was used. Coating liquid composition: polyvinyl butyral resin (# 5000-A, manufactured by Denki Kagaku Kogyo) 0.20 part Isocyanate (Coronate 2030, manufactured by Nippon Polyurethane) 0.20 part Polyester resin (Vylon 200, manufactured by Toyobo) 0.50 part Methyl ethyl ketone / Toluene (weight ratio 1/1) 9.00 parts

Example 4 A thermal transfer image-receiving sheet of the present invention was obtained in the same manner as in Example 1 except that the following coating liquid was used in place of the coating liquid in Example 1. Coating solution composition: polyvinyl butyral resin (# 5000-A, manufactured by Denki Kagaku Kogyo) 0.20 part Isocyanate (Coronate 2030, manufactured by Nippon Polyurethane) 0.20 part Polyester resin (Vylon 200, manufactured by Toyobo) 0.50 part Amino Modified silicone (KF-393, Shin-Etsu Chemical Co., Ltd.) 0.05 part Epoxy-modified silicone (X-22-343, Shin-Etsu Chemical Co., Ltd.) 0.05 part Methyl ethyl ketone / toluene (weight ratio 1/1) 9.00 parts

Example 5 A thermal transfer image-receiving sheet of the present invention was obtained in the same manner as in Example 1 except that the following coating liquid was used in place of the coating liquid in Example 1. Coating liquid composition; vinyl chloride-vinyl acetate copolymer (# 1000-GK, manufactured by Denki Kagaku Kogyo) 0.65 part Isocyanate (Coronate 2030, manufactured by Nippon Polyurethane) 0.35 part Methyl ethyl ketone / toluene (weight ratio 1/1) ) 9.00 copies

Example 6 A thermal transfer image-receiving sheet of the present invention was obtained in the same manner as in Example 1 except that the following coating liquid was used in place of the coating liquid in Example 1. Coating liquid composition; vinyl chloride-vinyl acetate copolymer (# 1000-GK) 0.65 part Isocyanate (Coronate 2030, made by Nippon Polyurethane) 0.35 part Amino-modified silicone (KF-393, Shin-Etsu Chemical Co., Ltd.) 0 0.05 part Epoxy modified silicone (X-22-343, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.05 part Methyl ethyl ketone / toluene (weight ratio 1/1) 9.00 parts

Example 7 A thermal transfer image-receiving sheet of the present invention was obtained in the same manner as in Example 1 except that the following coating liquid was used in place of the coating liquid in Example 1. Coating liquid composition; vinyl chloride-vinyl acetate copolymer (# 1000-GK) 0.30 part Isocyanate (Coronate 2030, made by Nippon Polyurethane) 0.15 part Polyester resin (Vylon 600, manufactured by Toyobo) 0.60 part Methyl ethyl ketone / Toluene (weight ratio 1/1) 9.00 parts

Example 8 A thermal transfer image-receiving sheet of the present invention was obtained in the same manner as in Example 1 except that the following coating liquid was used in place of the coating liquid in Example 1. Coating solution composition; vinyl chloride-vinyl acetate copolymer (# 1000-GK) 0.45 part Chelate compound (Organics TC200, manufactured by Matsumoto Kosho) 0.05 parts Polyester resin (Vylon 600, manufactured by Toyobo) 0. 50 parts Amino-modified silicone (KF-393, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.05 part Epoxy-modified silicone (X-22-343, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.05 part Methyl ethyl ketone / toluene (weight ratio 1/1) 9. 00 copies

Example 9 The surface of a 12 μm-thick polyester film (trade name “Lumirror”, manufactured by Toray Industries, Inc.) was coated with the coating solution for the receiving layer of Example 4 by a bar coater to give 3.0 g / m ² when dried. At a ratio of 15 g / m ² when dried in the same manner as above with the following adhesive solution. Was coated and dried to form an adhesive layer to obtain a receptor layer transfer film used in the present invention. Coating liquid composition for pressure-sensitive adhesive layer ; emulsion-type pressure-sensitive adhesive (E-1054, manufactured by Soken Kagaku Co., Ltd.) 100 parts water 30 parts The above-mentioned receptive layer transfer film is used as copy paper (Xerox M
The surface of a paper (thickness: 90 μm) was overlaid, and the both were passed through a laminator to be bonded, and then the substrate film was peeled off to transfer the dye-receiving layer to obtain a thermal transfer image-receiving sheet of the present invention.

Comparative Example 1 A thermal transfer image-receiving sheet of Comparative Example was obtained in the same manner as in Example 1 except that the following coating liquid was used in place of the coating liquid in Example 1. Coating liquid composition; polyvinyl butyral resin (# 5000-A, manufactured by Denki Kagaku Kogyo) 1.00 part Methyl ethyl ketone / toluene (weight ratio 1/1) 9.00 parts Comparative Example 2 Instead of the coating liquid in Example 1. A thermal transfer image-receiving sheet of a comparative example was obtained in the same manner as in Example 1 except that the following coating liquid was used. Coating solution composition: polyvinyl butyral resin (# 5000-A, manufactured by Denki Kagaku Kogyo) 0.90 part Amino-modified silicone (KF-393, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.05 part Epoxy-modified silicone (X-22-343, Shin-Etsu Chemical Co., Ltd.) 0.05 parts Methyl ethyl ketone / toluene (weight ratio 1/1) 9.00 parts Comparative Example 3 The following coating liquid was used in place of the coating liquid in Example 1, and other examples were used. A thermal transfer image-receiving sheet of Comparative Example was obtained in the same manner as in. Coating liquid composition; vinyl chloride-vinyl acetate copolymer (# 1000-GK) 0.45 part Amino-modified silicone (KF-393, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.05 part Epoxy-modified silicone (X-22-343, Shin-Etsu Chemical Co., Ltd.) 0.05 parts Methyl ethyl ketone / toluene (weight ratio 1/1) 9.00 parts

On the other hand, a dye layer-forming ink composition having the following composition was prepared, and a 6 μm-thick polyethylene terephthalate film having a back surface subjected to heat treatment had a dry coating amount of 1.0.
A thermal transfer sheet was obtained by coating and drying with a wire bar so as to obtain g / m ² . Ink composition; C.I. I. Disperse Blue 24 1.0 part Polyvinyl butyral resin 10.0 parts Methyl ethyl ketone / toluene (weight ratio 1/1) 90.0 parts Thermal transfer test; The thermal transfer sheet described above and the thermal transfer image-receiving sheets of the present invention and comparative examples described above , The respective dye layers and the dye receiving surface are faced to each other and overlapped, and the video printer VY-1
00 (manufactured by Hitachi, Ltd.), using a thermal head from the back surface of the thermal transfer sheet, a head applied voltage of 11.0 V and an applied pulse width of 16 msec. / Line to 1 msec. Step pattern that decreases sequentially for each, 6 lin in the sub-scanning direction
After recording with a thermal head under the condition of e / mm (33.3 msec./line) to form a cyan image, various performances such as releasability of the both were examined, and the results shown in Table 1 below were obtained.

[0026]

[Table 1]

[0027]

[Effects] According to the present invention as described above, by incorporating a cross-linked product comprising a hydroxyl group-containing thermoplastic resin and a cross-linking agent in the dye receiving layer, excellent releasability from the thermal transfer sheet during image formation and color development are achieved. A thermal transfer image-receiving sheet capable of forming a recorded image excellent in density, sharpness and various durability can be provided.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsura Yamaguchi 1-1-1 Ichigayakaga-cho, Shinjuku-ku, Tokyo Dai Nippon Printing Co., Ltd.

Claims (7)

[Claims] 1. A thermal transfer image-receiving sheet comprising a base sheet and a dye-receiving layer formed on at least one surface of the base sheet, wherein the dye-receiving layer contains a crosslinked product of a hydroxyl group-containing thermoplastic resin and a crosslinking agent. A thermal transfer image-receiving sheet characterized by. 2. The thermal transfer image-receiving sheet according to claim 1, wherein the hydroxyl group-containing thermoplastic resin is a polyvinyl acetal resin. 3. The thermal transfer image-receiving sheet according to claim 1, wherein the polyvinyl acetal resin has a polyvinyl alcohol unit content of 5 to 50% by weight. 4. The hydroxyl group-containing thermoplastic resin is vinyl chloride-
The thermal transfer image-receiving sheet according to claim 1, which is a vinyl acetate copolymer. 5. The thermal transfer image-receiving sheet according to claim 1, wherein the vinyl chloride-vinyl acetate copolymer has a polyvinyl alcohol unit content of 1 to 30% by weight. 6. The receiving layer comprises 10 to 80% by weight of the receiving layer resin.
The thermal transfer image-receiving sheet according to claim 1, which contains the dye-dyeable resin. 7. The thermal transfer image-receiving sheet according to claim 1, which contains a release agent.