JP2835111B2 - Thermal transfer image receiving sheet - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a thermal transfer image-receiving sheet, and more particularly to a thermal transfer image-receiving sheet, which can form a high-quality image without toddling or the like, and further has blocking resistance, fusion resistance, and image storability. The purpose of the present invention is to provide a thermal transfer image-receiving sheet excellent in such properties.

(Prior art and its problems) Conventionally, various thermal transfer methods are known. Among them, a sublimable dye is used as a recording material, and the sublimable dye is supported on a sheet of a base material such as paper or a plastic sheet to perform thermal transfer. Sheet and
There have been proposed methods of forming various full-color images on a thermal transfer image-receiving sheet dyeable with a sublimable dye, for example, a thermal transfer image-receiving sheet provided with a dye-receiving layer on the surface of paper or a plastic film.

In this case, a thermal head of a printer is used as a heating means, and a large number of three or four color dots are transferred to the thermal transfer image receiving sheet by heating for a very short time,
The multicolor dots reproduce a full-color image of a document.

The image formed in this way is very clear because the coloring material used is a dye, and is excellent in transparency, so that the obtained image is excellent in the reproducibility and gradation of intermediate colors. It is possible to form a high-quality image which is similar to an image by offset printing or gravure printing, and is comparable to a full-color photographic image.

As the thermal transfer image receiving sheet used in the sublimation type thermal transfer method as described above, a sheet provided with a dye receiving layer from a resin having good dye-dyeing properties on the surface of a base sheet such as paper or synthetic paper is used. .

When the above-mentioned dye-receiving layer is formed of a resin having a high glass transition temperature (Tg) such as polycarbonate, the cushioning property of the dye-receiving layer is low, and the heat of the thermal head during the thermal transfer causes the dye-receiving layer to be heated. Are not easily deformed, so that the adhesiveness between the thermal transfer sheet and the dye receiving layer is poor, and dot missing easily occurs in the printed image. Such a defect becomes more remarkable when the surface smoothness of the substrate sheet or the dye receiving layer is poor, and a high-resolution image cannot be formed.

On the other hand, if the dye receiving layer is formed of a resin having a low Tg such as polyethylene, the cushioning property at the time of printing is good, so there is no problem of missing dots as described above, but blocking occurs before and after printing on the thermal transfer image receiving sheet. There is a problem in that the image is easily generated, and the releasability between the thermal transfer sheet and the image receiving sheet is poor at the time of printing. Further, there is a problem that the formed image is blurred or blurred during preservation and is poor in preservability.

Accordingly, an object of the present invention is to provide a thermal transfer image-receiving sheet capable of forming a high-quality image without missing dots or the like, and further having excellent anti-blocking properties, anti-fusing properties, image storability and the like.

(Means for Solving the Problems) The above object is achieved by the present invention described below.

That is, the present invention comprises a substrate sheet, a cushion layer formed on the surface thereof and a dye receiving layer formed thereon, and the cushion layer is formed by extrusion laminating a resin having a glass transition temperature of 100 ° C. or lower. A heat transfer image-receiving sheet, wherein the glass transition temperature of the dye-receiving layer-forming resin is 100 ° C. or higher.

(Action) The glass transition temperature between the substrate sheet and the dye receiving layer is
By forming the cushion layer by extrusion laminating a resin having a temperature of 100 ° C. or less, a suitable cushioning property can be obtained even if the dye receiving layer is formed of a resin having a relatively high Tg (Tg is 100 ° C. or more). A thermal transfer image-receiving sheet that can form a high-quality image without missing dots and has excellent blocking resistance, fusion resistance, image storability, and the like is provided.

Further, the thermal transfer image-receiving sheet is provided very economically by forming the cushion layer by extrusion lamination, and in a more preferred embodiment, the thermal transfer image-receiving sheet having excellent anti-curl properties is obtained by extruding a resin on the same back surface. It can be a sheet.

Preferred Embodiment 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 base sheet, a cushion layer formed on the surface of the base sheet, and a dye receiving layer formed thereon.

As the base sheet used in the present invention, paperboard, medium quality paper, high quality paper, art paper, coated paper, cast coated paper,
Natural paper such as kraft paper, synthetic resin emulsion impregnated paper,
Polyolefins such as polyethylene and polypropylene, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyvinylidene chloride, polyvinylidene fluoride, polysulfone, polyether, nylon,
Examples thereof include plastic films such as aromatic polyamide, polyimide, and polyxylene, aluminum foil, nonwoven fabric, synthetic paper, and a laminate thereof.

The thickness of these substrate sheets may be arbitrary, for example, 10
A thickness of about 300 μm is generally used. Furthermore, these base sheets are used as sizing agents, fixing agents, paper strength agents, fillers,
Additives such as an antistatic agent, a dye, a fluorescent brightener, an antioxidant, and a lubricating agent may be contained inside or on the surface.

The cushion layer formed on the surface of the base sheet is made of Tg
Is formed by extrusion lamination from a resin having a temperature of 100 ° C. or lower. Examples of preferred resins for forming the cushion layer include, for example, high density polyethylene, medium density polyethylene, low density polyethylene, polypropylene, ethylene /
Examples of resins include polyolefin resins such as vinyl acetate copolymers, polyester resins such as polyethylene terephthalate, ionomer resins, nylon, polystyrene, and polyurethane resins, which have a small neck-in and have relatively good drawdown properties. These resins can be used alone or as a mixture. The thickness of such a cushion layer is
A thickness of about 15 to 40 μm is suitable. If it is too thin, the cushioning property is insufficient, while if it is too thick, it is disadvantageous in terms of weight and economy.

An organic and / or inorganic filler can be contained in the cushion layer made of the above resin, and examples of the organic filler include resin powders such as benzoguanamine, nylon, and polycarbonate. For example, titanium oxide, zinc oxide, barium sulfate, magnesium carbonate, calcium carbonate, alumina, silica,
Examples thereof include kaolin, clay, silicone powder, graphite, carbon, and the like. In particular, when titanium oxide is included in the cushion layer, the whiteness of the dye-receiving layer is preferably increased. As the titanium oxide, both anatase type and rutile type can be used. Such fillers are preferably used in a proportion of 3 to 60% by weight, especially 10 to 30% by weight of the cushion layer.

Furthermore, the cushion layer contains additives such as dyes, pigments, fluorescent brighteners, antioxidants, antistatic agents, lubricants, ultraviolet absorbers, heat stabilizers, light stabilizers, etc. Can be added.

In forming the cushion layer, it is preferable to perform an anchor treatment for improving the adhesion between the cushion layer and the base sheet. As the anchor treatment, a polyester resin, a polyurethane resin, an acrylic polyol-based resin, a vinyl chloride / vinyl acetate copolymer resin or the like may be used alone or as a mixture, and if necessary, a reactive curing agent such as polyisocyanate, titanate and / or silane One or more layers may be added by adding a coupling agent such as a coupling agent, ion irradiation treatment such as corona treatment and plasma treatment, radiation treatment such as ultraviolet rays and electron beams, solvent treatment, and flame treatment. Alternatively, one or a combination of these processing methods may be used as the anchor processing.

The dye-receiving layer formed on the surface of the cushion layer may be formed from any resin as long as it is a resin having a dye-receiving property conventionally used for forming a dye-receiving layer of a thermal transfer image-receiving sheet of this type. Is also good. For example, preferred examples include polyester, polyacrylate, polycarbonate, polyvinyl acetate, styrene acrylate resin, those having an ester bond such as vinyl toluene acrylate resin, those having a urethane bond such as a polyurethane resin, and amide bonds such as a polyamide. Having a urea bond such as a urea resin, polycaprolactone, polystyrene, poly-α-methylstyrene, a copolymer of a styrene monomer and another monomer, polyvinyl chloride, polyacrylonitrile, polyvinyl butyral, and polyvinyl acetal And other resins having a highly polar bond.

Preferred specific examples include a mixture of a saturated polyester and a vinyl chloride / vinyl acetate copolymer resin. In this case, the vinyl chloride / vinyl acetate copolymer resin has a vinyl chloride component content of 85 to 97% by weight. With a degree of polymerization of 200
It is preferably about 800 to 800. The copolymer is not limited to a copolymer of vinyl chloride and vinyl acetate, and may contain other monomer components such as a vinyl alcohol component and a maleic acid component.

The Tg of the resin for forming a dye-receiving layer as described above is 100 ° C. or higher, and preferably has a Tg of 100 to 120 ° C., and when Tg is lower than 100 ° C., there is no point in providing a cushion layer, and there is no point in printing. The anti-fusing property, blocking resistance, and image storability are insufficient. On the other hand, when the Tg exceeds 150 ° C., the function of the cushion layer is not sufficiently exhibited even if the cushion layer is provided, and the prevention of dot missing is not sufficient.

Dye receiving layer, on at least one surface of the cushion layer, the binder resin as described above, for example, a release agent,
A dispersion obtained by dissolving a necessary additive such as an antioxidant and an ultraviolet absorber in an appropriate organic solvent or dispersing in an organic solvent or water is used, for example, a gravure printing method, a screen printing method, and a gravure printing method. It is formed by applying and drying by a forming means such as a reverse roll coating method using a plate.

In forming the dye receiving layer, an anchor treatment as described above can be performed in order to increase the adhesion between the dye receiving layer and the cushion layer, and similarly, the whiteness of the dye receiving layer is improved to improve the transfer image. For the purpose of further increasing the sharpness of the toner, white pigments such as the above-mentioned titanium oxide can be included.

The dye-receiving layer formed as described above may have any thickness, but generally has a thickness of 1 to 50 μm. Further, such a dye receiving layer is preferably a continuous coating, but may be formed as a discontinuous coating using a resin emulsion or a resin dispersion.

Further, the image receiving sheet of the present invention preferably has an anti-curl layer formed on the back surface thereof. The anti-curl layer may be formed of the same resin as the cushion layer, or may be formed of another resin. However, it is preferable that the anti-curl layer be formed of the same resin because the effect of preventing the curl can be easily obtained. Further, it may be formed from a resin having a Tg of 100 ° C. or higher. The forming method is not particularly limited, but extrusion lamination is economical. Needless to say, by including additives such as a lubricant and an antistatic agent in the anti-curl layer, performance such as slipperiness and antistatic property of the image receiving sheet can be imparted. The thickness of such an anti-curl layer is
A thickness similar to that of the cushion layer is preferred because the curl prevention effect is high. If the thickness is too small, the curl prevention effect is insufficient. On the other hand, if the thickness is too large, the weight becomes large and uneconomical.

The thermal transfer sheet used when performing thermal transfer using the thermal transfer image-receiving sheet of the present invention as described above is provided with a dye layer containing a sublimable dye on paper or a polyester film. Any of them can be used as it is in the present invention.

As a means for applying thermal energy at the time of thermal transfer, any conventionally known applying means can be used. For example, recording is performed by a recording device such as a thermal printer (for example, Video Printer VY-100, manufactured by Hitachi, Ltd.). By controlling the time, by applying heat energy of about 5 to 100 mJ / mm ² , the intended purpose can be sufficiently achieved.

(Effects) According to the present invention as described above, a resin having a glass transition temperature of 100 ° C. or less is extrusion-laminated between a base sheet and a dye-receiving layer to form a cushion layer, thereby reducing the dye-receiving amount. Even if it is formed from a resin having a relatively high Tg (Tg is 100 ° C. or higher), an appropriate cushioning property can be obtained. Therefore, a high-quality image without dot missing can be formed, and blocking resistance, fusion resistance, A thermal transfer image-receiving sheet having excellent image storability and the like is provided.

Further, the thermal transfer image-receiving sheet can be provided very economically by forming the cushion layer by extrusion lamination, and in a further preferred embodiment, the resin is extruded and laminated on the back surface similarly to the thermal transfer image-receiving sheet having excellent anti-curl properties. It can be a sheet.

(Examples) Next, the present invention will be described more specifically with reference to examples and comparative examples. In the following description, parts and% are based on weight unless otherwise specified.

Example 1 A coated paper (basis weight 145 g / m ² , thickness 120 μm) was used as a base sheet.
m), the surface of the base sheet is corona-treated, and an extruded resin comprising 100 parts of low-density polyethylene (Tg 20 ° C.) and 15 parts of anatase-type titanium oxide is extruded and laminated to a thickness of 30 μm to form a cushion layer. Was formed on the back surface, and an anti-curl layer having a thickness of 30 μm having antistatic properties was formed from an extruded resin comprising 100 parts of low-density polyethylene and 5 parts of an antistatic agent.

Furthermore the coating amount after drying the dye-receiving layer composition of the following composition to a surface of the cushion layer was coated with a wire bar so as a 4.0 g / m ^2, forming a dye-receiving layer and dried for 10 minutes at 120 ° C. Thus, a thermal transfer image-receiving sheet of the present invention was obtained.

Dye receiving layer composition: polyvinyl butyral resin (BV-5, Sekisui Chemical Co., Ltd.)
16.5 parts Amino-modified silicone (KF-393, Shin-Etsu Chemical Co., Ltd.) 1.2 parts Epoxy-modified silicone (X-22-343, Shin-Etsu Chemical Co., Ltd.) 1.2 parts Methyl ethyl ketone / toluene (Weight ratio 1/1) 100 parts Example 2 In Example 1, the cushion layer was made of an extruded resin comprising 100 parts of a polypropylene resin (Tg 30 ° C.), 12 parts of anatase type titanium oxide and 0.1 part of a fluorescent whitening agent, and was 25 μm thick. Extruded resin consisting of 100 parts of polypropylene resin, 10 parts of silicone powder and 0.5 part of phosphoric ester was laminated on the back surface to form a 25 μm thick anti-curl anti-curl layer, and otherwise the same as in Example 1. Thus, a thermal transfer image-receiving sheet of the present invention was obtained.

Example 3 A thermal transfer image-receiving sheet of the present invention was obtained in the same manner as in Example 2, except that the cushion layer was 25 μm and the back layer was 10 μm.

Example 4 The same as Example 1 except that the following composition was used in place of the composition for the receiving layer of Example 1.

Polyvinyl butyral resin (BV-1, Sekisui Chemical Co., Ltd.)
16.5 parts Amino-modified silicone (X-22-3050C, Shin-Etsu Chemical Co., Ltd.) 1.2 parts Epoxy-modified silicone (X-22-3000E, Shin-Etsu Chemical Co., Ltd.) 1.2 parts Methyl ethyl ketone / Toluene (1/1 by weight) 100 parts Example 5 Same as Example 1 except that the following composition was used in place of the composition for the receiving layer of Example 1.

Polycarbonate resin (Iupilon 2000E, Mitsubishi Gas Chemical Co., Ltd., Tg = 140 ° C) 15.0 parts Amino-modified silicone (X-22-3050C, Shin-Etsu Chemical Co., Ltd.) 1.2 parts Epoxy-modified silicone (X-22) -3000E, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.2 parts Methylene chloride 100 parts Comparative Example 1 Comparative Example 1 was repeated except that both the cushion layer and the back layer were formed of polystyrene (Tg110 ° C.). A thermal transfer image-receiving sheet was obtained as an example.

Comparative Example 2 A thermal transfer image-receiving sheet of Comparative Example was obtained in the same manner as in Example 1 except that the cushion layer and the back layer were not provided.

Comparative Example 3 In Example 1, a low-density polyethylene (Tg 20 ° C) 100 was formed on the base sheet without forming the cushion layer.
Part, 10 parts of amino-modified silicone and 10 parts of epoxy-modified silicone, a 20 μm-thick dye-receiving layer is directly formed, and further laminated on the back with 100 parts of low-density polyethylene and 5 parts of antistatic agent. Then thickness
A 20 μm anti-curl layer was formed to obtain a thermal transfer image-receiving sheet of Comparative Example.

Example of use As a base film, a 4.5 μm thick polyethylene terephthalate film (Lumirror 5A-F53, manufactured by Toray Industries, Inc.) having a heat-resistant treatment on the back side of the surface on which the dye layer is to be formed, is used for forming the following dye layer. The thickness of the ink composition when dried is 1.
It was applied by gravure printing so as to be 0 g / m ² and dried at 80 ° C. for 5 minutes to prepare a thermal transfer sheet.

Ink composition for forming dye layer Disperse dye (Kayaset Blue 714, Nippon Kayaku Co., Ltd.)
4.0 parts polyvinyl butyral resin (Sekisui Chemical Co., Ltd.)
Esrec BX-1) 4.3 parts Toluene 40.0 parts Methyl ethyl ketone 40.0 parts Using the thermal transfer image-receiving sheets of the above Examples and Comparative Examples and the above-mentioned thermal transfer sheets, an image was obtained using a commercially available color video printer (VY-110, manufactured by Hitachi, Ltd.). The formed image was observed for dot omission of the printed image and blur / bleeding of the image in a moisture resistance test (60 ° C., 90% RH for 24 hours). The results shown in Table 1 below were obtained.

Dot missing: ：: A beautiful printed image with no missing dots in the entire high-density printing portion to the low-density printing portion.

：: Slight dot missing was observed in the low-density printing part, but no dot missing was found in the medium-density printing part to the high-density printing part, and a beautiful printed image was obtained as a whole.

×: Many dot omissions were observed in the entire high density print area to the low density print area.

* 1: Print curl was observed.

* 2: Printing sensitivity was low, and blocking and fusion occurred.

Storage The printed image was stored at 60 ° C. for 200 hours and visually observed.

A: A beautiful printed image is maintained in the entire high-density printing to low-density printing area as before the test. No blur or bleeding is observed in the image. ×: The blur or bleeding of the image is clearly recognized.

Comprehensive evaluation ◎: Best ○: Practical enough ×: Practical low

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-302091 (JP, A) JP-A-64-44781 (JP, A) JP-A-61-295085 (JP, A) JP-A-62 176896 (JP, A) JP-A-3-173690 (JP, A) JP-A-3-124492 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41M 5 / 38-5 / 40

Claims (5)

(57) [Claims] 1. A substrate sheet, comprising a cushion layer formed on the surface thereof and a dye receiving layer formed thereon, wherein the cushion layer is formed by extrusion laminating a resin having a glass transition temperature of 100 ° C. or less. A thermal transfer image-receiving sheet, wherein the dye-receiving layer-forming resin has a glass transition temperature of 100 ° C. or higher. 2. The thermal transfer image-receiving sheet according to claim 1, wherein the cushion layer contains an organic and / or inorganic filler. 3. The thermal transfer image-receiving sheet according to claim 2, wherein the inorganic filler is titanium oxide. 4. The thermal transfer image-receiving sheet according to claim 2, wherein the filler content is 60% by weight or less of the resin. 5. The thermal transfer image-receiving sheet according to claim 1, wherein an anti-curl layer is formed on the back surface.