JP3745062B2 - Thermal transfer image receiving sheet - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thermal transfer image-receiving sheet that is superposed on a thermal transfer sheet and obtains an image by thermally transferring a coloring material based on a sublimation dye using a thermal head as a device, and more specifically, an image from a high color to a low density part. Belongs to a thermal transfer image-receiving sheet that uniformly forms a recorded image.
[0002]
[Prior art]
Among various thermal transfer recording systems, a heat-sensitive sublimation dye that uses a sublimable dye as a color material and transfers the color material to a thermal transfer image-receiving sheet using a thermal head that generates heat in response to a recording signal. A transfer recording system is known. This recording method uses a dye as a color material and can obtain density gradation, so that the image is extremely high-definition, and is excellent in halftone color reproducibility and gradation reproducibility. It is possible to form an image with an image quality comparable to a silver salt photograph.
[0003]
There are a wide variety of specific uses on the image receiving side on which printing or image formation is performed by this heat-sensitive sublimation dye transfer recording system.
Typical examples include printing proofs, image output, CAD / CAM and other design and design output, various medical analytical instruments such as CT scan, measurement instrument output applications, and as an alternative to instant photography In addition, output of face photographs to ID cards, ID cards, credit cards, and other cards, and further use as composite photographs and commemorative photographs in amusement facilities such as amusement parks, museums, and aquariums.
[0004]
The heat-sensitive sublimation dye transfer image-receiving sheet used in a wide variety of applications as described above is a base sheet made by laminating paper and foam film with dry lamination, and an intermediate layer is provided on the foam film side to provide a smooth surface. And an image receiving sheet on which a receiving layer is formed.
The foam sheet used for the base sheet gives cushioning properties, and the paper gives the image receiving sheet a specific texture or strain that the paper has.
[0005]
[Problems to be solved by the invention]
However, when the receiving layer is inferior in smoothness and has irregularities on the surface, or the receiving layer containing the foamed film is softened at the temperature at the time of transfer, the irregularity (paper eyes) caused by the paper fibers may occur. is there. In this way, when the smoothness at the time of transfer is inferior, the dark portion where the amount of the sublimation dye is large can be developed without any trouble, but the portion where the amount of the sublimation dye is small (low concentration, light portion) There is a problem in that a desired color is not generated and color loss occurs because the dye is not completely colored in the recess.
[0006]
The unevenness on the surface of the receiving layer is due to paper eyes, and in order to conceal it, a technique has been disclosed such as providing a cushioning property by using a foam film for the base film. However, the cushioning effect of the foam film cannot completely prevent the unevenness caused by the paper eyes appearing on the surface of the receiving layer, and cannot reproduce a full-color image having no color loss from light to dark. There was a problem. It is an object of the present invention to provide a thermal transfer image receiving sheet that can prevent unevenness due to paper fibers on the surface of the thermal transfer image receiving sheet and express a full color image without color loss.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention
A thermal transfer image-receiving sheet having at least a sublimation dye receiving layer on one side of the base sheet, wherein the base sheet is at least a polypropylene foam from the receiving layer side, and a second foam is polyethylene terephthalate all SANYO film and the paper were laminated in this order, and the paper side of the side where the receiving layer is not formed, the third foamed film is a polyethylene terephthalate, a fourth foamed film is a polypropylene laminated, the It is a thermal transfer image receiving sheet in which the third foam film and the second foam film, and the fourth foam film and the first foam film are equal .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a preferred embodiment will be described based on the drawings. A base sheet in which a third foam film 22 and a fourth foam film 32 are laminated on the side opposite to the paper receiving layer can be used like the thermal transfer image receiving sheet 11 shown in FIG . Here, the third foam film uses the same material as the second foam film 21 and the fourth foam film uses the same material as the first foam film 31. In addition, the foam film 32 constitutes the back layer 6 that adjusts the sliding property when the printer is transported to the thermal transfer image receiving sheet 11.
[0009]
The thermoplastic resin that is the material of the first foamed film is polypropylene, and the thermoplastic resin that is the material of the second foamed film is polyethylene terephthalate.
[0010]
A foamed film having bubbles inside can be produced by adding an inorganic or organic filler to the above resin and performing a stretching treatment after film formation.
Examples of the filler that can be used include inorganic fillers such as titanium oxide, silicon oxide, magnesium oxide, barium sulfate, zinc oxide, talc, and clay, and polystyrene, melamine, acrylic, and organic silicone organic fillers.
[0011]
The foamed film may be a single layer, but may have a multilayer structure. Specific examples of the multi-layer foam film include commercially available synthetic paper YUPO (manufactured by Oji Oil Synthetic Paper), Toyopearl SS (manufactured by Toyobo), pyrene film (manufactured by Toyobo), Crisper (manufactured by Toyobo), W -900 (made by Diafoil Hoechst), E-60 (made by Toray), etc. are mentioned.
Examples of the multilayer structure include a three-layer structure of foamed layer / non-foamed layer / foamed layer. In this specification, a multilayered film and a single-layered film are collectively referred to as a foamed film. .
[0012]
Since the first foamed film has a large influence on the print density and sensitivity, a foamed polypropylene film of a foamed polyolefin film having appropriate heat resistance and cushioning properties is used . In addition, when a foam film having a two-layer structure such as a foam layer / non-foam layer is used, if the receptor layer is formed on the foam layer side, the cushioning property of the foam layer is good for the image formed on the receptor layer. Improve sensitivity. Even when the receiving layer is formed on the non-foamed layer side, if the thickness of the non-foamed layer does not adversely affect the sensitivity of the image and smoothes the fine unevenness of the foamed layer, the non-foamed layer A foamed film having a layer on the receiving layer side is also preferably used.
[0013]
The first foamed film preferably has a thickness of about 20 to 100 μm, and particularly preferably 35 to 60 μm. If the thickness is less than 20 μm, cushioning properties are poor, and printing sensitivity and density are lowered. On the other hand, if it is thicker than 100 μm, curling occurs, which is not preferable.
[0014]
The second film prevents unevenness on the paper surface from appearing on the surface of the receiving layer, and among the materials mentioned above, it is necessary to use a foamed film made of polyester polyethylene terephthalate from the viewpoint of heat resistance and rigidity. is there. A foamed film having a non-foamed layer on the surface is preferably used with the non-foamed layer on the receiving layer side. The thickness of the second foamed film is preferably about 20 to 100 μm, particularly preferably in the range of 25 to 50 μm. If it is thinner than 20 μm, a paper grain appears on the surface of the receiving layer. On the other hand, when the thickness is more than 100 μm, it is not preferable because curling occurs and sensitivity of the receiving layer is lowered.
[0015]
Among these, materials using polypropylene or polyethylene terephthalate as a raw material are materials that have moderate heat resistance, cushioning effect, printing density, and easy disposal that do not generate acid gas by incineration or the like.
[0016]
The paper used in the present invention is preferably a paper excellent in thermal stability such as heat shrinkage and surface smoothness as compared with the foamed film. Specifically, those using natural pulp such as fine paper, coated paper, art paper, cast coated paper, glassine paper, etc. are preferable materials because the entire base sheet can be given a texture and strain like paper. is there. In particular, cast-coated paper is an excellent material with smooth surface.
[0017]
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 may be transparent, but a white film is used to obtain the same concealment property as paper. It is preferable.
The thickness of the paper or plastic film is preferably about 25 to 150 μm. When the thickness is less than 25 μm, the texture and strain like paper are lowered, and when the thickness is more than 150 μm, curling occurs and sensitivity of the receiving layer is lowered.
[0018]
In addition, the fourth foamed film is bonded to the third foamed film. The third foamed film uses the second foamed film, and the fourth foamed film uses the same foamed film as the first foamed film. Thus, a symmetrical multilayer structure centered on paper or plastic film is very preferable in terms of curling prevention.
[0019]
Adhesion between each layer is made by laminating with a conventionally known wet lamination or dry lamination between absorbent paper and non-absorbent plastic, and between plastic film and foam film between non-absorbent films. It can be laminated by dry lamination.
Wet lamination is performed using emulsion glue such as vinyl acetate resin or acrylic resin, and dry lamination is a sandwich that uses a heat-cured thermoplastic resin as an adhesive resin layer in addition to a reaction-curing urethane adhesive. Can be done by lamination.
[0020]
The thickness of the base sheet is preferably 100 to 250 μm in consideration of the rigidity of the image receiving sheet and the transportability of the printer. Further, the thickness of the entire thermal transfer image receiving sheet is preferably from 100 to 300 μm.
[0021]
Furthermore, as other embodiment, it is the form which provided the intermediate | middle layer 4 between the foamed film and the receiving layer of the side in which the receiving layer of the base material sheet 10 is provided. It is preferable that the unevenness generated when the foamed film is printed by heating is suppressed and smoothed, the adhesion to the receiving layer 5 is strengthened, and the whiteness of the thermal transfer image receiving sheet can be increased.
The intermediate layer 4 includes a varnish mainly composed of a thermoplastic polyester 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, styrene. -Acrylic copolymer dispersion can be used. If necessary, pigments such as titanium oxide, calcium carbonate, magnesium carbonate, aluminum hydroxide, barium sulfate, and fluorescent colorants can be included.
The intermediate layer can be coated / formed with a coating liquid formed from the resin varnish by ordinary gravure reverse coating, roll coating, air knife coating or the like.
And the coating amount is 3-20 g / m < ² > (solid content, it describes similarly below). When the coating amount is 3 g / m ² or less, the above function as the intermediate layer cannot be obtained, and when it is ² g / m ² or less, the sensitivity of the receiving layer is lowered, which is not preferable.
The intermediate layer can also be formed by dry lamination of a film-like material prepared separately or by hot melt coating as a hot melt resin.
[0022]
As the receiving layer 5 provided in the intermediate layer, a conventionally known one can be used.
Various additives such as a release agent are added to a varnish mainly composed of a resin that easily dyes a coloring material, 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. Polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polystyrene resins, polyamide resins, copolymers of olefins such as ethylene and propylene and other vinyl monomers, ionomers, cellulose derivatives, etc. Among these, polyester resins and vinyl resins are preferable.
[0023]
The receptor layer may contain a release agent in order to prevent thermal fusion with the thermal transfer sheet when forming an image. As the release agent, silicone oil, phosphate plasticizer, and fluorine compound can be used. Among these, silicone oil is preferably used. The addition amount of the release agent is preferably 0.2 to 30 parts by weight with respect to 100 parts by weight of the resin forming the receiving layer.
Various additives may be added to the receiving layer as necessary. For example, when the image receiving sheet requires high whiteness, a fluorescent whitening agent or a white pigment can be added to the receiving layer.
In addition, an antistatic agent is added to the receptive layer, or applied to one or both of the receptive layer and the back side of the base sheet in order to prevent charging in the other cases when the thermal transfer image-receiving sheet is conveyed by the printer. It can also be formed.
The receptor 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 or an extrusion coating method. Then, the coating amount is, 0.5 to 10 g / m ² is preferred.
[0024]
You may provide a primer layer as needed for the purpose of improving adhesiveness between a base material sheet and the above-mentioned intermediate | middle layer and / or receiving layer. In order to further stabilize the adhesion, the intermediate layer or the receiving layer can be applied by performing pretreatment such as corona discharge treatment or ozone treatment on the base sheet or 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 by using various curing agents or other methods can be used. Specifically, linear polyesters, chlorinated polypropylene, modified polyolefins, urethane resins, acrylic resins, ionomers, resins obtained by curing prepolymers containing monofunctional and / or polyfunctional hydroxyl groups with isocyanate, etc. are used. it can. And the coating amount is 0.1-2 g / m < ² >.
[0025]
The back layer is used for adjusting slippage of the thermal transfer image-receiving sheet to prevent poor running 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, nitrified cotton, etc., as a lubricant, silicone, liquid paraffin, hydrocarbon such as low molecular polyethylene, higher fatty acid, fatty acid amide, polyvalent Add a fatty acid ester of alcohol, a phosphate ester plasticizer, other metal soap, and adjust the coating solution from a varnish consisting of a composition dissolved in a solvent suitable for the coating method. It is provided and formed by coating. Further, the above-mentioned lubricant can be included in the foamed film so as to have the same function as the back layer.
[0026]
【Example】
EXAMPLE As shown in FIG. 1 , a biaxially stretched polyethylene terephthalate film (trade name Lumirror E-63 (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 as shown in FIG. The adhesive layer 7 having the following composition is applied and dried at 3 g / m ² , and the first foamed film 31 is a foamed polypropylene film having a thickness of 38 μm (trade name Toyopearl 4255 (manufactured by Toyobo Co., Ltd.)) Next, 2 g / m ² of the intermediate layer coating solution having the following composition was applied onto the surface of the first foamed film 31 and the dried intermediate layer 4 and / or the receiving layer coating solution was 4 g / m ^2. The coated and dried receptor layer 5 was formed, and a laminate sheet on the receptor layer side was prepared.
(adhesive)
Polyfunctional polyol: Takelac A-969-V 30 parts by weight
(Made 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 solution)
-Urethane resin N-5199 (Nippon Polyurethane Industry Co., Ltd.) 20 parts by weight-Isocyanate: Takenate A-14 6 parts by weight
(Made by Takeda Pharmaceutical Co., Ltd.)
・ Methyl ethyl ketone: toluene = 1: 1 74 parts by weight (receiving layer coating solution)
・ 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
(Denka rack # 400A Same as above)
Polyester (Byron 600 manufactured by Toyobo Co., Ltd.) 11.2 parts by weight Vinyl modified silicone X-62-1212 2.0 parts by weight
(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 part by weight ・ Methyl ethyl ketone: toluene = 1: 1 78 parts by weight On the other hand, The Lumirror E-63 having a thickness of 50 μm is coated and dried with 3 g / m ² of the adhesive having the above composition to provide an adhesive layer 7, and the Toyopearl P4255 having a thickness of 38 μm is formed as the fourth film 32. And dry lamination. Next, 3 g / m ² of a back layer coating solution having the following composition was applied to the surface of the fourth foamed film 32 and dried to provide a back layer 6 to prepare a back layer laminated sheet.
(Back layer coating liquid)
-Urethane resin N-5199 (manufactured by Nippon Polyurethane Industry Co., Ltd.) 10 parts by weight-Isocyanate A-14 (manufactured by Takeda Pharmaceutical Co., Ltd.) 3 parts by weight-Calcium carbonate 10 parts by weight-Vinyl-modified silicone X-6-1212 2 parts by weight
(Shin-Etsu Chemical Co., Ltd.)
・ Methyl ethyl ketone: toluene = 1: 1 75 parts by weight And, the adhesive layer 7 is applied to the surface of the second foamed film 21 and the third plastic film 22 by applying 4 g / m ² of the above adhesive and drying. The thermal transfer image-receiving sheet 11 of the present invention was constructed by laminating on both sides of coated paper 60 μm (product name, New Top, Oji Paper Co., Ltd.) by dry lamination.
[0027]
(Comparative example)
In place of the second and third foamed films in the examples, a non-foamed polyethylene terephthalate film plastic film (trade name: Lumirror S-10 manufactured by Toray Industries, Inc.) having a thickness of 50 μm was used. A thermal transfer image receiving sheet 11 of a comparative example similar to the example was prepared.
[0028]
As a result of transferring the samples of Examples and Comparative Examples using a printer “UPC 5010A” manufactured by Sony Corporation, the surface of the thermal transfer image-receiving sheet of the Examples is smooth, and irregularities based on paper fibers and unevenness of paper appear. There wasn't. Further, the formed image was clear and high in density, and even in the light color portion, there was no unevenness. In addition, no curling occurred during production and printing.
On the other hand, in the heat transfer image sheet of the comparative example, unevenness based on paper fibers and unevenness of paper appeared in the formed image, and uneven color occurred in the light-colored portion, and a clear image could not be obtained.
[0029]
【The invention's effect】
As described above, the thermal transfer image-receiving sheet of the present invention is smooth with no irregularities on the surface, and has the effect of forming a clear and high-quality image with no color unevenness.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view illustrating a configuration of a thermal transfer image receiving sheet of the present invention .
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Paper or plastic film 2, 21 2nd foam film 3, 31 1st foam film 4 Intermediate | middle layer 5 Receiving layer 6 Back surface layer 7 Adhesive layer 10 Base material sheet 11 Thermal transfer image receiving sheet 22 3rd foam film 32 1st Four foam films

Claims (1)

A thermal transfer image-receiving sheet having at least a sublimation dye receiving layer on one side of the base sheet, wherein the base sheet is at least a polypropylene foam from the receiving layer side, and a second foam is polyethylene terephthalate all SANYO film and the paper were laminated in this order, and the paper side of the side where the receiving layer is not formed, the third foamed film is a polyethylene terephthalate, a fourth foamed film is a polypropylene laminated, the A thermal transfer image-receiving sheet , wherein the third foam film and the second foam film, and the fourth foam film and the first foam film are equal .

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