JPH10181227A - Heat transfer image receiving sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat transfer image receiving sheet, the surface of an accepting layer of which is excellent in smoothness, the image heat-transferred on which is clear and has a high density and even the image in a light-colored part of which has no unevenness, in the heat transfer image receiving sheet, on which an accepting layer of sublimation dye having a paper as a base material is provided. SOLUTION: A base material sheet 10 of a heat transfer image receiving sheet, in which at least a sublimation dye accepting layer is provided on one side of the base material sheet 10, at least a first foamed film 3, a second foamed film 2 and a paper or a plastic film 1 are laminated in the order named from the accepting layer 5 side. The preferable first foamed film 3 is polyolefin or polypropylene and the preferable second foamed film 2 is polyester.

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 which is superimposed on a thermal transfer sheet and thermally transfers a coloring material with a sublimable dye using a thermal head as a device to obtain an image. It belongs to a thermal transfer image-receiving sheet which forms a recorded image uniformly and uniformly on an image reaching a low density portion.

[0002]

2. Description of the Related Art In various thermal transfer recording systems, a sublimable dye is used as a color material, and the color material is transferred to a thermal transfer image receiving sheet using a thermal head which generates heat in accordance with a recording signal. A known heat-sublimation dye transfer recording system is known. Since this recording method uses a dye as a coloring material and can obtain a density gradation, an image is extremely high-definition, and since it has excellent halftone color reproducibility and gradation reproducibility, It is possible to form an image of image quality comparable to a silver halide photograph.

[0003] Specific applications on the image receiving side on which printing or image formation is carried out by this heat-sensitive sublimation type dye transfer recording system are also diverse. Typical examples are print proofs, image output, CAD / CAM and other design and design outputs, various medical analysis equipment such as CT scan, output for measurement equipment, and as an alternative to instant photography. , And the output of photo ID to ID cards, credit cards, and other cards, amusement park,
It can be used as a composite photograph in amusement facilities such as museums and aquariums, and as a commemorative photograph.

A heat-sensitive sublimation type dye transfer image receiving sheet used for a wide variety of applications as described above is obtained by laminating paper and a foamed film by dry lamination as a base sheet and forming an intermediate layer on the foamed film side. An image receiving sheet provided with a receiving layer was formed to be smooth. The foam sheet used as the base sheet gives cushioning properties, and the paper gives the image receiving sheet the unique texture and stiffness of paper.

[0005]

However, the smoothness of the receiving layer is poor and the surface has irregularities, or the receiving layer containing the foamed film is softened at the temperature at the time of transfer and the irregularities caused by the fibers of the paper. (Paper eyes) may occur. When the smoothness at the time of transfer is inferior in this way, the coloring of the dark portion where the amount of the sublimable dye is large can be performed without any trouble, but the portion where the amount of the sublimable dye is small (the portion of low density and light color) is Since the coloring of the dye is not completely performed in the concave portions, a desired color is not formed, and there is a problem that color missing occurs.

[0006] The irregularities on the surface of the receiving layer are due to the grain of the paper. In order to conceal the irregularities, a technique has been disclosed in which a foam film is used as a base film to provide cushioning properties. However, the simple cushion effect of the foamed film cannot completely prevent the irregularities due to the eyes of the paper appearing on the surface of the receiving layer, and cannot reproduce a full-color image without color loss from light to dark. There was a problem. SUMMARY OF THE INVENTION It is an object of the present invention to provide a thermal transfer image receiving sheet which can prevent a surface of the thermal transfer image receiving sheet from being uneven due to paper fibers and can express a full-color image without color loss.

[0007]

According to the present invention, there is provided a thermal transfer image-receiving sheet having at least one sublimable dye-receiving layer on one side of a substrate sheet. At least a first foam film from the layer side,
It is a thermal transfer image receiving sheet in which a second foamed film and a paper or plastic film are laminated in this order. The first foamed film is a thermal transfer image receiving sheet made of polyolefin. The first foamed film is a thermal transfer image-receiving sheet made of polypropylene. And
The second foamed film is a thermal transfer image receiving sheet made of polyester. Further, the second foam film,
This is a thermal transfer image receiving sheet made of polyethylene terephthalate. Further, the thermal transfer image-receiving sheet is obtained by laminating a third foamed film on paper or a plastic film on the side on which the receiving layer is not formed. Further, the thermal transfer image-receiving sheet has the same thickness as the third foamed film and the total thickness of the first and second foamed films. Further, the present invention is a thermal transfer image-receiving sheet in which a third foamed film and a fourth foamed film are laminated on paper or a plastic film on the side on which the receiving layer is not formed. The third foamed film and the second foamed film, and the fourth foamed film and the first foamed film are the same thermal transfer image receiving sheet.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments will be described below with reference to the drawings. As shown in FIG. 1, the thermal transfer image receiving sheet 11 of the present invention
A base sheet 10 in which the second foamed film 2 and the first foamed film 3 are laminated on one side is prepared, and the receiving layer 5 is provided to form the thermal transfer image receiving sheet 11. Then, as shown in FIG. 2, an intermediate layer 4 for adjusting the smoothness by covering the unevenness of the foamed film on the surface of the first foamed film 3.
Is provided, and a receiving layer 5 is further formed to form the thermal transfer image-receiving sheet 1.
1. As shown in FIG. 3, a base sheet in which the second foamed film 2 and the first foamed film 3 are laminated via the adhesive layer 7 at a temperature close to room temperature, that is, at a temperature at which the foamed film does not re-foam. Intermediate layer 4 at 10
And the thermal transfer image-receiving sheet 11 provided with the receiving layer 5. Then, like the thermal transfer image receiving sheet 11 shown in FIG. 4, a third foam film 22 is formed on the side opposite to the paper receiving layer.
Further, a base sheet in which the fourth foamed film 32 is laminated can be used. Here, the third foamed film uses the same material as the second foamed film 21, and the fourth foamed film uses the same material as the first foamed film 31. The foam film 32 constitutes the back surface layer 6 for adjusting the slipperiness of the thermal transfer image receiving sheet 11 when the printer is transported.

The thermoplastic resin used as the material of the first and second foam films is polyethylene, polypropylene, polymethylpentene, polystyrene, polyethylene terephthalate, polyethylene naphthalate, polyamide, polyimide, polyvinyl chloride, polyvinylidene chloride, Examples include polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polycarbonate, polymethyl methacrylate, polybutene-1, polyetheretherketone, polysulfone, polyethersulfone, polyetherimide, and polyphenylenesulfide.

A foamed film having bubbles therein can be produced by adding an inorganic or organic filler to the above resin, forming a film, and performing a stretching treatment. Examples of the filler include inorganic fillers such as titanium oxide, silicon oxide, magnesium oxide, barium sulfate, zinc oxide, talc, and clay; and organic fillers such as polystyrene, melamine, acrylic, and organic silicone.

The foamed film may be composed of a single layer, but may have a multilayer structure. Specific examples of the multilayer-structured foam film include commercially available synthetic paper YUPO (manufactured by Oji Yuka Synthetic Paper), Toyopearl SS (manufactured by Toyobo), Pyrene film (manufactured by TOYOBO), Krispar (manufactured by TOYOBO), W
-900 (manufactured by Diafoil Hoechst), E-60 (manufactured by Toray) and the like. As an example of the multilayer structure, there is a three-layer structure of a foamed layer / non-foamed layer / foamed layer. In the present specification, a multilayered structure and a single-layered structure are collectively described as a foamed film. .

Since the first foamed film greatly affects the printing density and sensitivity, it is preferable to use a foamed polyolefin film, particularly a foamed polypropylene film, having appropriate heat resistance and cushioning properties. Further, when a foamed film having a two-layer structure such as a foamed layer / a non-foamed layer is used, if the receiving layer is formed on the foamed layer side, the good cushioning property of the foamed layer will improve the image formed on the receiving layer. Improve sensitivity. Further, even when the receiving layer is formed on the non-foamed layer side, the thickness of the non-foamed layer does not adversely affect the sensitivity of the image,
In addition, a foamed film having a non-foamed layer on the side of the receptor layer is also preferably used as long as it can smooth the fine irregularities of the foamed layer.

The first foamed film has a thickness of 20 to 100 μm.
The thickness is preferably about 35 to 60 μm is a particularly preferable range. If the thickness is less than 20 μm, the cushioning property is poor, and the printing sensitivity and density are reduced. Also, 100μ
If the thickness is too large, curling occurs, which is not preferable.

The second film is used to prevent the unevenness of the paper surface from appearing on the surface of the receiving layer. Among the above-mentioned materials, the use of a foamed film made of polyester, particularly polyethylene terephthalate, is advantageous in terms of heat resistance and rigidity. Is preferred. Further, a foamed film having a non-foamed layer on its surface is preferably used with the non-foamed layer facing the receiving layer.
The thickness of the second foamed film is preferably about 20 to 100 μm, and particularly preferably in the range of 25 to 50 μm. 20
If it is too thin, paper grain will appear on the surface of the receiving layer. On the other hand, if the thickness is more than 100 μm, curling occurs and the sensitivity of the receiving layer decreases, which is not preferable.

Among these, those made of polypropylene or polyethylene terephthalate are materials having an appropriate heat resistance, a cushioning effect, a printing density, and an excellent easy-to-dispose property in which no acid gas is generated by incineration or the like. It is.

The paper used in the present invention is preferably one which is superior in heat stability such as heat shrinkage and surface smoothness as compared with a foamed film. Specifically, high-quality paper, coated paper, art paper, cast coated paper, those using natural pulp such as glassine paper, the entire base sheet, such as paper-like texture,
It is a preferable material because it can be stiff. Particularly, cast coated paper is an excellent material having a smooth surface.

Further, a plastic film may be used instead of paper using natural pulp. As the plastic film, a film made of the same material as the above-mentioned foamed film can be used, but an unfoamed film can be used, and it may be transparent, but a white film is used to obtain the same concealing property as paper. Is preferred. The thickness of the paper or plastic film is preferably about 25 to 150 μm. If the thickness is less than 25 μm, the texture and stiffness of paper decrease, and if the thickness is more than 150 μm, curling occurs and the sensitivity of the receiving layer decreases, which is not preferable.

Further, in another embodiment, the base sheet of the present invention has a structure in which a third foam film is further attached to the opposite side of the paper or plastic film from the receiving layer to prevent curling. Preferred for. As the third film, the same foam films as the first and second films described above can be used, but the thickness of the third foam film is equal to the total thickness of the first and second foam films. Is preferred. Further, a fourth foamed film may be further bonded to the third foamed film. In this case, the third foamed film is the second foamed film, and the fourth foamed film is the first foamed film. Using the same foam film,
It is very preferable to have a multilayer structure symmetrical around a paper or plastic film in terms of curling prevention.

Adhesion between the layers is performed by laminating the absorbent paper and the non-absorbent plastic with a conventionally known wet lamination or dry lamination. Lamination with a foamed film can be performed by dry lamination.
Wet lamination is performed using an emulsion paste such as vinyl acetate resin or acrylic resin, and dry lamination is performed in addition to reaction-curable urethane-based adhesives.
It can be performed by sandwich lamination in which a thermoplastic resin that has been melted by heat is used as an adhesive resin layer.

The thickness of the base sheet is 100 to 250 μm in consideration of the rigidity of the image receiving sheet and the suitability of the printer for conveyance.
m is preferred. Further, the thickness of the entire thermal transfer image receiving sheet is 1
00 to 300 μm is preferred.

In still another embodiment, an intermediate layer 4 is provided between the foamed film on the side of the base sheet 10 on which the receiving layer is provided and the receiving layer. It is preferable to suppress unevenness generated when the foamed film is printed by heating, to smooth the foamed film, to strengthen the adhesion to the receiving layer 5, and to increase the whiteness of the thermal transfer image receiving sheet. The intermediate layer 4 is made of a varnish mainly composed of a thermoplastic resin such as a saturated polyester soluble in an organic solvent, a vinyl chloride-vinyl acetate copolymer, an acrylic resin, a polyurethane or a polyolefin resin, styrene-butadiene, or styrene. -An acrylic copolymer dispersion can be used. If necessary, pigments such as titanium oxide, calcium carbonate, magnesium carbonate, aluminum hydroxide, barium sulfate, and fluorescent coloring agents can be included. The intermediate layer is formed by coating the coating liquid formed from the resin varnish with a normal gravure reverse coat, roll coat,
It can be coated and formed with an air knife coat or the like. The coating amount is 3 to 20 g / m ² (solid content, hereinafter similarly described). When the coating amount is 3 g / m ² or less, the above function as the intermediate layer cannot be obtained. When the coating amount is 2 g / m ² or less, the sensitivity of the receiving layer decreases, which is not preferable. Also, the middle layer
A separately prepared film can be formed by dry lamination or hot melt coating as a hot melt resin.

As the receiving layer 5 provided on the intermediate layer, a conventionally known one can be used. A varnish mainly composed of a resin which can easily dye a coloring material is added with various additives such as a release agent, if necessary. Typical resins that are easily dyed include polyolefins such as polypropylene, halogenated resins such as polyvinyl chloride and polyvinylidene chloride, vinyl resins such as polyvinyl acetate and polyacrylate, and copolymers thereof. ,polyethylene terephthalate,
Polyester resins such as polybutylene terephthalate, polystyrene resins, polyamide resins, copolymers of olefins such as ethylene and propylene with other vinyl monomers, ionomers, simple substances such as cellulose derivatives, or mixtures thereof can be used. Among them, polyester resins and vinyl resins are preferable.

The receiving layer may contain a release agent to prevent thermal fusion with the thermal transfer sheet when forming an image. As the release agent, silicone oil, phosphate ester plasticizer, and fluorine compound can be used. Among them, silicone oil is preferably used. The amount of the release agent added was 0.2 to 100 parts by weight of the resin forming the receiving layer.
-30 parts by weight are preferred. Various additives may be added to the receiving layer as needed. For example, when high whiteness is required for the image receiving sheet, a fluorescent whitening agent or a white pigment can be added to the receiving layer. Further, during the transfer of the thermal transfer image-receiving sheet by the printer, in order to prevent charging in other cases, an antistatic agent is added to the receiving layer, or the receiving layer is coated on one or both of the back surface of the substrate sheet. It can also be formed. The receiving layer is formed by a general method such as a roll coating method, a bar coating method, a gravure coating method, a gravure reverse coating method, and an extrusion coating method. And the coating amount is 0.5
-10 g / m ² are preferred.

A primer layer may be provided as needed between the substrate sheet and the above-mentioned intermediate layer and / or receiving layer for the purpose of improving the adhesiveness. Further, in order to further stabilize the adhesiveness, the intermediate layer or the receiving layer may be coated by performing a pretreatment such as a corona discharge treatment or an ozone treatment on the base sheet or the intermediate layer in advance. As the primer layer, a layer obtained by curing a thermoplastic resin, a thermosetting resin, or a thermoplastic resin having a functional group using various curing agents or other methods can be used. Specifically, linear polyester,
Chlorinated polypropylene, modified polyolefin, urethane resin, acrylic resin, ionomer, monofunctional and / or
Alternatively, a resin obtained by curing a prepolymer containing a polyfunctional hydroxyl group with isocyanate or the like can be used. And the coating amount is 0.1 to ² g / m ² .

The back surface layer is used for adjusting the slip of the thermal transfer image-receiving sheet to prevent running defects in the printer and is provided on the outermost layer on the back surface. For example, linear polyester, chlorinated polypropylene, modified polyolefin, urethane resin, acrylic resin, polyamide,
Silicone, liquid paraffin,
Addition of hydrocarbons such as low molecular weight polyethylene, higher fatty acids, fatty acid amides, fatty acid esters of polyhydric alcohols, phosphate ester plasticizers, and other metal soaps, and further dissolved in a solvent suitable for the coating method A coating liquid is prepared from the resulting varnish, and if necessary, a primer layer is provided to form a coating. Further, the above-mentioned lubricant can be included in the foamed film to have the same function as that of the back surface layer.

[0026]

【Example】

(Embodiment) As shown in FIG. 4, a biaxially stretched polyethylene terephthalate film (trade name Lumirror E-63 (trade name: Toray Industries, Inc.) having a thin non-foamed layer on the surface of the receiving layer having a thickness of 50 μm as the second foamed film 21 3 g / m ^{2 of} an adhesive layer 7 having the following composition and dried to form a first foamed film 31, a 38 μm-thick foamed polypropylene film (trade name: Toyopearl 4255 (manufactured by Toyobo Co., Ltd.)) Then, 2 g / m ^{2 of} an intermediate layer coating solution having the following composition was applied to the surface of the first foamed film 31 and dried, and / or 4 g of a receptor layer coating solution was applied.
m ² coated and dried receiving layer 5 was formed, and a laminated sheet on the receiving layer side was prepared. (Adhesive) Polyfunctional polyol: Takerac A-969-V 30 parts by weight (manufactured by Takeda Pharmaceutical Co., Ltd.) Isocyanate: Takenate A-5 (same as above) 10 parts by weight Ethyl acetate 60 parts by weight (intermediate layer coating) 20 parts by weight of urethane resin N-5199 (manufactured by Nippon Polyurethane Industry Co., Ltd.)-6 parts by weight of isocyanate: Takenate A-14 (manufactured by Takeda Pharmaceutical Co., Ltd.)-Methyl ethyl ketone: toluene = 1: 74 weight Part (coating solution for receiving layer) ・ 7.2 parts by weight of vinyl chloride / vinyl acetate copolymer (Denka vinyl # 1000A manufactured by Denki Kagaku Kogyo Co., Ltd.) ・ 1.6 parts by weight of vinyl chloride / styrene / acrylic copolymer (Dencarak # 400A, same as above) ・ Polyester (Byron 600 manufactured by Toyobo Co., Ltd.) 11.2 parts by weight ・ Vinyl-modified silicone X- 2-1212 2.0 parts by weight (manufactured by Shin-Etsu Chemical Co., Ltd.)-CAT PLR-5 (catalyst same as above) 1.0 part by weight-CAT PL-50T (catalyst same as above) 1.2 parts by weight-methyl ethyl ketone: Toluene = 1: 78 parts by weight On the other hand, 3 g / m ² of the adhesive having the above composition was added to the third foamed film 22 (Lumirror E-63 having a thickness of 50 μm).
After coating and drying, the adhesive layer 7 was provided, and the fourth film 32 was dry-laminated with the Toyopearl P4255 having a thickness of 38 μm. Next, a back layer coating solution having the following composition was applied to the surface of the fourth foamed film 32 at a rate of 3 g / m 3.
² Coating and drying were performed to provide a back layer 6 to prepare a laminated sheet on the back layer side. (Backside layer coating solution)-Urethane resin N-5199 (Nippon Polyurethane Industry Co., Ltd.) 10 parts by weight-Isocyanate A-14 (Takeda Pharmaceutical Co., Ltd.) 3 parts by weight-Calcium carbonate 10 parts by weight-Vinyl Modified silicone X-62-1212 2 parts by weight (manufactured by Shin-Etsu Chemical Co., Ltd.) ・ Methyl ethyl ketone: toluene = 1: 1 75 parts by weight And the surface of the second foamed film 21 and the third plastic film 22 are described above. 4 g / m of adhesive
² Coating and drying to provide adhesive layer 7 and coat paper 60μm
(New Top Oji Paper Co., Ltd. product name) was laminated on both sides by dry lamination to form the thermal transfer image-receiving sheet 11 of the present invention.

(Comparative Example) A non-foamed polyethylene terephthalate film plastic film (trade name: 50 μm) instead of the second and third foam films of the examples
A thermal transfer image-receiving sheet 11 of a comparative example was prepared in the same manner as in the example except that Lumirror S-10 manufactured by Toray Industries, Inc. was used.

Samples of Examples and Comparative Examples were prepared by Sony Corporation.
As a result of transfer using a printer “UPC 5010A”, the surface of the thermal transfer image receiving sheet of the example is smooth,
No irregularities due to paper fibers or irregularities in papermaking appeared. Further, the formed image was clear, high in density, and had no unevenness even in a light color portion. In addition, no curling occurred during production or printing. On the other hand, in the thermal transfer image sheet of the comparative example, irregularities based on paper fibers and irregularities in papermaking appeared in the formed image, color irregularities occurred in light-colored portions, and clear images could not be obtained.

[0029]

As described above, the thermal transfer image-receiving sheet of the present invention has a smooth surface with no irregularities, has no color unevenness, and has the effect of forming a clear, high-density and good image. .

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a basic configuration of a thermal transfer image-receiving sheet of the present invention.

FIG. 2 is a schematic sectional view showing another configuration of the thermal transfer image receiving sheet of the present invention.

FIG. 3 is a schematic sectional view showing another configuration of the thermal transfer image receiving sheet of the present invention.

FIG. 4 is a schematic cross-sectional view illustrating a configuration of a thermal transfer image receiving sheet of an example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Paper or plastic film 2, 21 Second foam film 3, 31 First foam film 4 Intermediate layer 5 Reception layer 6 Back layer 7 Adhesive layer 10 Base sheet 11 Thermal transfer image receiving sheet 22 Third foam film 32 Four foam films

Claims (9)

[Claims] 1. A thermal transfer image-receiving sheet having at least one sublimable dye receiving layer on one side of a substrate sheet, wherein the substrate sheet is at least a first foamed film from the receiving layer side.
A thermal transfer image-receiving sheet comprising a second foamed film and a paper or plastic film laminated in this order. 2. The thermal transfer image-receiving sheet according to claim 1, wherein the first foamed film is a polyolefin. 3. The thermal transfer image-receiving sheet according to claim 2, wherein said first foamed film is polypropylene. 4. The thermal transfer image-receiving sheet according to claim 1, wherein the second foamed film is a polyester. 5. The thermal transfer image-receiving sheet according to claim 4, wherein said second foamed film is polyethylene terephthalate. 6. The thermal transfer image-receiving sheet according to claim 1, wherein a third foamed film is laminated on the paper or plastic film on the side where the receiving layer is not formed. 7. The thermal transfer image-receiving sheet according to claim 6, wherein the thickness of the third foamed film is equal to the total thickness of the first and second foamed films. 8. The thermal transfer image-receiving sheet according to claim 1, wherein a third foamed film and a fourth foamed film are laminated on the paper or plastic film on the side on which the receiving layer is not formed. 9. The thermal transfer image-receiving sheet according to claim 1, wherein the third foamed film and the second foamed film, and the fourth foamed film and the first foamed film are equal. .