JPH082127A - Thermal transfer printing paper - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a thermal transfer printing paper capable of forming an image with high transfer sensitivity without losing glossiness in a wide range of low gradation to high gradation. [Structure] A thermal transfer printing paper is constructed by providing a two-layered dye receiving layer comprising a lower dye receiving layer 2 and an upper dye receiving layer 3 formed thereon on a substrate 1. Here, the glass transition point of the thermoplastic resin forming the upper dye receiving layer 3 is set to be higher than the glass transition point of the thermoplastic resin forming the lower dye receiving layer 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer printing system suitable for a thermal transfer recording system, particularly a sublimation type thermal transfer recording system. More specifically, the present invention relates to a thermal transfer printing paper capable of receiving a dye with high transfer sensitivity in the entire gradation range from low gradation to high gradation.

[0002]

2. Description of the Related Art Thermal transfer recording in which an ink ribbon is heated by a thermal head or a laser according to image information and dye is transferred from the ink ribbon to photographic paper by thermal melting or thermal diffusion or sublimation to form an image on the photographic paper. The method is widely adopted. In particular, in recent years, a so-called sublimation type thermal transfer recording system, in which a thermal diffusion dye such as a sublimation dye is used to form a continuous gradation full-color image, has been attracting attention. For example, it has been attempted to selectively heat an ink ribbon according to an image signal of a video image to form an image on a video printing paper.

As such a video printing paper, as shown in FIG. 2, a sheet-like base material 21 made of polypropylene or the like on which a dye receiving layer 22 is formed is used. The dye receiving layer is a layer that receives the dye transferred from the ink ribbon by heating and holds the image formed by the dye. Such a dye receiving layer 22 is made of a thermoplastic resin which is easily dyed with a dye, such as polyester, polycarbonate, polyvinyl chloride, vinyl chloride copolymer such as vinyl chloride-vinyl acetate copolymer, and the like.
A resin composition obtained by dissolving or dispersing a polyurethane resin, polystyrene, AS resin, ABS resin, or cellulose ester resin and an additive such as a plasticizer or an ultraviolet absorber in a solvent such as toluene is applied to the base material 21. And then dried to form a single layer (JP-A-4-296).
595, etc.).

[0004]

However, when thermal transfer is performed on a single-layer dye receiving layer, there is a problem in that an image cannot be recorded uniformly and with high transfer sensitivity in the entire range from low gradation to high gradation. It was For example, in order to improve the transfer sensitivity in the low gradation region where the applied energy applied is low, the dye receiving layer is mainly composed of a thermoplastic resin having a relatively low glass transition point (Tg) of about 70 ° C. Then, in the high gradation range where the applied energy applied is high, there is a problem that the thermoplastic resin is excessively softened and the surface of the dye receiving layer is roughened to become matte and its glossiness is lowered. vice versa,
In order to prevent the surface of the dye receiving layer from matting in the high gradation range and to enhance the transfer sensitivity, a relatively high T of about 110 ° C.
When the dye-receiving layer is composed mainly of a thermoplastic resin having g, the dye-receiving layer is not sufficiently softened in the low gradation range where the applied energy is small, and therefore the adhesion to the ink ribbon is insufficient and the transfer sensitivity is low. There was a problem that it decreased.

The present invention is intended to solve the above-mentioned problems of the prior art and is for thermal transfer capable of forming an image with high transfer sensitivity without losing glossiness in a wide range of low gradation to high gradation. The purpose is to provide photographic paper.

[0006]

DISCLOSURE OF THE INVENTION The inventor of the present invention has a conventional single-layered dye-receiving layer having a two-layer structure, and the Tg of a thermoplastic resin mainly constituting the surface-side dye-receiving layer is The inventors have found that the above-mentioned objects can be achieved by making the dye-receiving layer higher than the Tg of the thermoplastic resin mainly constituting the dye-receiving layer, and have completed the present invention.

That is, the present invention relates to a thermal transfer printing paper comprising a base material and a dye-receiving layer containing a thermoplastic resin formed on the base material, and a lower layer in which the dye-receiving layer is arranged on the base material side. The glass transition point of the thermoplastic resin comprising the dye receiving layer and the upper dye receiving layer formed thereon and constituting the upper dye receiving layer is the glass transition point of the thermoplastic resin constituting the lower dye receiving layer. A photographic printing paper for thermal transfer characterized by being higher than the above.

The thermal transfer printing paper of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view of a thermal transfer printing paper according to a preferred embodiment of the present invention. As shown in the drawing, the thermal transfer printing paper of the present invention has a structure in which a lower dye receiving layer 2 and an upper dye receiving layer 3 are laminated on a substrate 1.

The lower dye receiving layer 2 and the upper dye receiving layer 3 are both mainly composed of a thermoplastic resin, and the thermoplastic resin forming the upper dye receiving layer 3 is a lower dye. A resin having a Tg higher than that of the thermoplastic resin forming the receiving layer is used. As a result, at the time of thermal transfer at a low gradation, the lower dye receiving layer 2 is sufficiently softened and functions as a cushion layer, even though the upper dye receiving layer 3 is formed of a thermoplastic resin having a high Tg. As a result, the adhesion between the upper dye receiving layer 3 and the ink ribbon is improved, so that the transfer sensitivity can be improved. Further, at the time of thermal transfer in high gradation, since the upper dye receiving layer 3 is made of a thermoplastic resin having a high Tg, it is possible to prevent the surface of the printing paper from matting without being excessively softened. Therefore, the glossiness of the obtained image can be prevented from decreasing.

If the difference between the Tg of the thermoplastic resin forming the upper dye-receiving layer 3 and the Tg of the thermoplastic resin forming the lower dye-receiving layer 2 is too small, a single-layer dye-receiving layer is used. Since there is no great difference, the difference is preferably 20 ° C. or higher, more preferably 20 ° C. to 40 ° C.

When the Tg of the thermoplastic resin constituting the upper dye-receiving layer 3 is too low, matting cannot be sufficiently suppressed, and the transfer sensitivity in the entire too high gradation range is lowered. It is preferable to use one having Tg of 60 ° C to 120 ° C, more preferably 80 ° C to 100 ° C. Also,
As the thermoplastic resin constituting the lower dye-receiving layer 2, if the Tg is too low, the surface of the photographic paper is matted, and if it is too high, the transfer sensitivity in the low gradation range is lowered.
g is 40 ° C. to 100 ° C., more preferably 60 ° C. to 80 ° C.
Use one.

The Tg of the thermoplastic resin can be adjusted by appropriately adjusting the degree of polymerization of the resin itself and the amount of the soft segment introduced into the resin. It can also be carried out by adding a plasticizer.

The upper layer dye-receiving layer 3 has a layer thickness of preferably 1 to 6 μm, more preferably 2 to 4 μm, because if it is too thin, it becomes matte and if it is too thick, the sensitivity decreases. Further, the layer thickness of the lower dye receiving layer 2 is preferably 1 to 6 μm, and more preferably 2 to 4 μm, because if it is too thin, the transfer sensitivity will decrease, and if it is too thick, the surface of the photographic paper will be matted.

As the thermoplastic resin forming the upper dye receiving layer 3 and the thermoplastic resin forming the lower dye receiving layer 2, the same kind of resin or different kinds of resins may be used. The thermoplastic resin conventionally used as a film forming component of the dye receiving layer of photographic paper can be used. For example, acetal resin, polyester resin, polyester polyurethane resin, polycarbonate resin, polyvinyl chloride resin, vinyl chloride-copolymer resin such as vinyl chloride-vinyl acetate copolymer or vinyl chloride-acryl copolymer, polyamide resin, poly Vinyl acetate resin, polyurethane resin, polystyrene resin, AS resin,
ABS resin, cellulose resin, cellulose ester resin, polyvinyl alcohol resin, acrylic resin, SB
Synthetic rubbers such as R and NBR can be used. You may use these individually or in mixture of 2 or more types. Among them, a cellulose ester resin, a butyral resin, an acetal resin, a polyester resin, a polyester polyurethane resin can be preferably used from the viewpoint of improving the sensitivity, and a polyester resin or a cellulose ester resin is particularly preferably used.

The upper dye receiving layer 3 and the lower dye receiving layer 2 may further contain various additives compatible with the above-mentioned resin components. For example, by forming an amorphous state by being compatible with a thermoplastic resin, promoting the diffusibility (dyeability) of the dye, and allowing the dye to penetrate into the dye receiving layer, light resistance and heat resistance can be improved. As an additive (sensitizer) for improving the properties, various esters, ethers, other hydrocarbon compounds and the like can be contained.

As such esters, ethers and hydrocarbon compounds, liquid or solid ones having a melting point of about -50 ° C to 150 ° C can be used. For example, as the esters, dimethyl phthalate, Phthalates such as diethyl phthalate, dioctyl phthalate, dicyclohexyl phthalate and diphenyl phthalate, isophthalates such as dicyclohexyl isophthalate, aliphatic dibasic esters such as dioctyl adipate, dioctyl sebacate and dicyclohexyl azelate, tris Phosphoric acid esters such as phenyl phosphate, tricyclohexyl phosphate, triethyl phosphate, dimethyl isophthalate,
Higher fatty acid esters such as diethyl isophthalate, butyl stearate, cyclohexyl laurate, silicic acid esters, boric acid esters and the like can be used. As the ethers, diphenyl ether, dicyclohexyl ether, methyl p-ethoxybenzoate, etc. can be used, and as the hydrocarbon compound,
Camphor, low molecular weight polystyrene, phenols such as p-phenylphenol, o-phenylphenol, N
-Ethyltoluenesulfonic acid amide or the like can be used.

In the lower dye receiving layer 2 or the upper dye receiving layer 3 of the thermal transfer printing paper of the present invention, the whiteness thereof is improved to enhance the sharpness of the image, and further, the surface of the thermal transfer printing paper is written. A fluorescent brightening agent and a white pigment may be contained in order to impart the property and prevent the retransfer of the formed image. As the fluorescent whitening agent and the white pigment, commercially available products can be used, and for example, Ubitex OB manufactured by Ciba-Geigy can be used as the fluorescent whitening agent.

Further, an antistatic agent may be used in the lower dye receiving layer 2 or the upper dye receiving layer 3 in order to prevent static electricity from being generated during running in the printer. Examples of the antistatic agent include cationic surfactants (quaternary ammonium salts, polyamine derivatives, etc.) anionic surfactants (alkylbenzene sulfonates, alkyl sulfate sodium salts, etc.), zwitterionic surfactants, Alternatively, various surfactants such as nonionic surfactants can be used. These antistatic agents may be contained in the lower dye receiving layer 2 or the upper dye receiving layer 3 or may be applied to the surface of the upper dye receiving layer 3 by coating or the like.

In addition to the above, the lower dye receiving layer 2 or the upper dye receiving layer 3 may be appropriately blended with various crosslinking agents such as a plasticizer, an ultraviolet absorber, an antioxidant and an isocyanate compound.

The thermal transfer printing paper of the present invention is characterized in that the dye receiving layer has a two-layer structure of the lower layer dye receiving layer 2 and the upper layer dye receiving layer 3 as described above. It can be configured in the same manner as the photographic printing paper. For example, as the base material 1, it is possible to use high-quality paper, paper such as coated paper, various plastic sheets, or a laminated sheet in which these are combined, as in the case of conventional printing paper.

If desired, a slipping layer may be provided on the surface of the substrate 1 opposite to the lower dye receiving layer 2.

The thermal transfer printing paper of the present invention can be produced by a known method. For example, the lower layer dye-receiving layer forming composition is coated on the substrate 1 with a wire bar or the like and dried to form the lower layer dye. It can be produced by forming the receiving layer 2 and further coating the composition for forming the upper dye receiving layer thereon and drying it to form the upper dye receiving layer 3.

An image can be formed on the thermal transfer printing paper of the present invention in the same manner as in the prior art, and the type of dye used is not particularly limited.

[0025]

In the thermal transfer printing paper of the present invention, the dye receiving layer has a two-layer structure of the lower layer dye receiving layer 2 and the upper layer dye receiving layer 3 from the side of the substrate 1, and the upper layer dye receiving layer 3 is mainly used. As the constituent thermoplastic resin, one having a Tg higher than that of the thermoplastic material mainly constituting the lower dye receiving layer 2 is used. Therefore, the transfer sensitivity in the low gradation range to the high gradation range can be improved without lowering the glossiness of the image surface.

[0026]

EXAMPLES The present invention will be specifically described below based on examples. In Examples and Comparative Examples, "part" means part by weight.

Example 1 A synthetic paper (FPG-150, manufactured by Mitsubishi Petrochemical Co., Ltd.) having a thickness of 150 μm was used as a substrate, and the composition for forming the lower dye receiving layer shown in Table 1 was 4 μm on the synthetic paper. It was applied so as to have a (dry thickness) and dried at 120 ° C. for 2 minutes to form a lower dye receiving layer. Further, a composition for forming an upper dye-receiving layer having a composition shown in Table 2 was applied so as to have a thickness of 6 μm (dry thickness) and dried at 120 ° C. for 2 minutes to form an upper dye-receiving layer. As a result, a thermal transfer printing paper having a dye receiving layer with a total thickness of 10 μm was obtained.

[0028]

[Table 1] Composition for forming lower dye-receiving layer Component name Amount (part) Cellulose acetate butyrate 100 (CAB-500-5, manufactured by E. Kodak) Diethyl isophthalate (plasticizer) 20 Polyisocyanate 5 (Takenate) D110N, manufactured by Takeda Pharmaceutical Co., Ltd.) Methyl ethyl ketone 200 Toluene 200 Note: Tg of a mixture of cellulose acetate butyrate and diethyl isophthalate is 65 ° C.

[0029]

[Table 2] Composition for forming upper dye-receiving layer Component name Amount used (part) Cellulose acetate butyrate (Tg 120 ° C) 100 (CAB-500-5, manufactured by E. Kodak) Polyisocyanate 5 (Takenate D110N, Takeda Yakuhin) Industrial Co., Ltd.) Methyl ethyl ketone 200 Toluene 200 Example 2 A thermal transfer printing paper was prepared in the same manner as in Example 1 except that the dye receiving layer forming compositions shown in Tables 3 and 4 were used.

[0030]

[Table 3] Lower layer dye receiving layer forming composition Component name Amount (part) Polyester resin (Tg65 ° C) 100 (UE-3200, manufactured by Unitika Ltd.) Polyisocyanate 5 (Takenate D110N, manufactured by Takeda Pharmaceutical Co., Ltd.) ) Methyl ethyl ketone 200 Toluene 200

[0031]

[Table 4] Composition of composition for forming upper dye receiving layer Component amount Amount (part) Acetal resin (Tg110 ° C) 100 (KS-1, manufactured by Sekisui Chemical Co., Ltd.) Polyisocyanate 5 (Takenate D110N, Takeda Pharmaceutical Co., Ltd.) Methyl ethyl ketone 200 Toluene 200 Example 3 A thermal transfer printing paper was produced in the same manner as in Example 1 except that the dye receiving layer forming compositions shown in Tables 5 and 6 were used.

[0032]

[Table 5] Composition for forming lower layer dye receiving layer Component name Amount (part) Polyester polyurethane resin (Tg59 ° C) 100 (Vylon UR1200, manufactured by Toyobo Co., Ltd.) Polyisocyanate 5 (Takenate D110N, Takeda Pharmaceutical Co., Ltd.) Manufactured) Methyl ethyl ketone 200 Toluene 200

[0033]

[Table 6] Composition for forming upper dye-receptive layer Component name Amount (part) Polyester polyurethane resin (Tg 83 ° C) 100 (Vylon UR1400, manufactured by Toyobo Co., Ltd.) Polyisocyanate 5 (Takenate D110N, Takeda Pharmaceutical Co., Ltd.) Methyl ethyl ketone 200 Toluene 200 Comparative Example 1 Except that an upper dye-receptive layer was not formed and the lower dye-receptive layer-forming composition of Example 1 was used to form a 10 μm (dry thickness) single-layer dye-receptive layer. A thermal transfer printing paper was prepared in the same manner as in Example 1.

(Evaluation) Sublimation transfer ink ribbon (VPM-3) was applied to the produced thermal transfer printing papers of Examples and Comparative Examples.
0ST, manufactured by Sony Corporation) was used to perform 12-step steer step printing by a sublimation color video printer (CVP-G7, manufactured by Sony Corporation). The image density of the 9th step as the low gradation range and the image density of the 1st step (MAX density) as the high gradation range are calculated by the Macbeth densitometer R.
It was measured using D-914. Further, the glossiness of the surface of the photographic paper in the first step was visually evaluated according to the following evaluation criteria. The results are shown in Table 7.

Glossiness Evaluation Criteria Rank State ○ When the surface is not roughened and the glossiness is not lost × When the surface is roughened and the glossiness is deteriorated

[0036]

[Table 7] Optical density 1 step 9 steps 1 step glossiness Example 1 1.25 2.45 ○ 2 1.12 2.42 ○ 3 1.36 2.55 ○ Comparative Example 1 0.92 2.20 × Table 7 As is clear from the above, the thermal transfer printing paper of this example has improved transfer sensitivity in the low gradation range to the high gradation range. Further, the glossiness of the image was not lost in the high gradation range.
On the other hand, the thermal transfer printing paper of Comparative Example had a lower transfer sensitivity than that of the Examples, and the glossiness in the high gradation range was lowered.

[0037]

According to the thermal transfer printing paper of the present invention, the transfer sensitivity can be improved in the low gradation range to the high gradation range. Further, it is possible to prevent the glossiness of the surface of the printing paper from being lowered even in the high gradation range.

[Brief description of drawings]

FIG. 1 is a sectional view of a thermal transfer printing paper of the present invention.

FIG. 2 is a sectional view of a conventional thermal transfer printing paper.

[Explanation of symbols]

 1 Base Material 2 Lower Dye Receiving Layer 3 Upper Dye Receiving Layer

Claims (5)

[Claims] 1. A thermal transfer printing paper comprising a substrate and a dye-receiving layer containing a thermoplastic resin formed thereon, wherein the dye-receiving layer is a lower dye-receiving layer arranged on the substrate side. It is composed of an upper dye receiving layer formed on it,
Further, a thermal transfer printing paper characterized in that the glass transition point of the thermoplastic resin constituting the upper dye receiving layer is higher than the glass transition point of the thermoplastic resin constituting the lower dye receiving layer. 2. The thermal transfer according to claim 1, wherein the difference between the glass transition point of the thermoplastic resin forming the upper dye receiving layer and the glass transition point of the thermoplastic resin forming the lower dye receiving layer is 20 ° C. or more. Photographic paper. 3. The glass transition point of the thermoplastic resin constituting the upper dye receiving layer is 60 ° C. to 120 ° C., and the glass transition point of the thermoplastic resin constituting the lower dye receiving layer is 40 ° C.
The thermal transfer printing paper according to claim 1 or 2, which has a temperature of 100 ° C. 4. The upper dye receiving layer has a layer thickness of 1 to 6 μm, and the lower dye receiving layer has a layer thickness of 1 to 6 μm.
4. The thermal transfer printing paper according to any one of 3 to 3. 5. A group in which the thermoplastic resin constituting the upper dye-receiving layer and the thermoplastic resin constituting the lower dye-receiving layer independently comprise cellulose ester resin, butyral resin, acetal resin, polyester resin, polyester polyurethane resin. The thermal transfer printing paper according to any one of claims 1 to 4, which is at least one selected from the following.