JPH02196692A - Thermal transfer sheet and method - Google Patents

Abstract

PURPOSE:To obtain a thermal transfer sheet capable of forming an image of high density at a high speed by incorporating a releasable silicone resin in a dye layer. CONSTITUTION:As the silicone resin used in a dye layer, for example, a modified silicone resin selected from epoxy modified, long chain alkyl modified, alkyl modified, carboxyl modified, higher alcohol modified, fluoro-fatty acid modified, fatty acid modified, alkyl aralkyl polyether modified, epoxy/polyether modified and polyether modified silicone resins is desirable and the addition amount thereof is pref. 1-20 pts.wt. per 100 pts.wt. of a dye forming resin. When the addition amount is too little, release effect is insufficient and, when the addition amount is too much, no pref. result is obtained, because dye transfer properties and film strength are lowered or a problem of the discoloration or preservability of a dye is generated. At the time of thermal transfer, a thermal transfer sheet wherein the dye layer is formed to the surface of a base film and an image receiving sheet wherein a dye receiving layer is provided to the surface of a base film are superposed so that the dye layer of the thermal transfer sheet is opposed to the receiving layer of the image receiving sheet and heated imagewise from the rear of the thermal transfer sheet.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a thermal transfer sheet and a thermal transfer method using sublimable dyes (thermally transferable dyes), and more specifically, to a thermal transfer sheet and a thermal transfer method that use sublimable dyes (thermally transferable dyes), and more specifically, to transfer images that are capable of high-speed recording and have high density. The purpose of the present invention is to provide a thermal transfer sheet and a thermal transfer method that can form a thermal transfer sheet.

(Prior art) Inkjet methods, thermal transfer methods, etc. have been developed as methods for providing excellent monochrome or full-color images easily and at high speed in place of conventional general printing methods. The most excellent method is the so-called sublimation thermal transfer method, which uses sublimable dyes, as it has excellent continuous gradation properties and provides full-color images comparable to color photographs.

The thermal transfer sheet used in the above-mentioned sublimation type thermal transfer method has a dye layer containing a sublimable dye formed on one side of a base film such as a polyester film, and a dye layer containing a sublimable dye is formed on one side of the base film to prevent the thermal head from sticking. A heat-resistant layer provided on the other side is generally used.

The dye layer surface of such a thermal transfer sheet is placed on an image receiving sheet having an image receiving layer made of polyester resin or the like, and by heating the thermal transfer sheet in an imagewise manner from the back side with a thermal head, the dye in the dye layer is transferred to the image receiving sheet. A desired image is formed.

(Problem to be Solved by the Invention) The thermal transfer method described above has the excellent advantage of being able to vary the density of the image by changing the temperature of the thermal head. However, if the temperature of the thermal head is raised, the binder forming the dye layer will soften and adhere to the image receiving sheet, causing the inconvenience that the thermal transfer sheet and the image receiving sheet will adhere. A problem arises in that the dye layer is peeled off and transferred directly to the surface of the image-receiving sheet.

One way to solve this problem is to include a release agent such as silicone oil in the dye-receiving layer of the image-receiving sheet, but since the silicone oil is liquid at room temperature, it may cause problems during storage. However, it has the disadvantage that it stands out on the surface of the receptor layer, causing blocking and contamination problems. On the other hand, there are methods that use thermosetting silicone oil, but these methods require heat treatment after forming the receptor layer.
There is a problem in that the production process is extremely complicated.

Furthermore, if a relatively large amount of silicone is added to give the receptor layer sufficient releasability, the dye receptivity may decrease or
A problem arises in that the storage stability of the image-receiving sheet deteriorates.

On the other hand, if a release agent is added to the dye layer of a thermal transfer sheet to the extent that it provides a release effect, problems such as precipitation of the dye, discoloration, etc. will occur, and storage stability will be reduced, making the sheet unusable.

Therefore, an object of the present invention is to achieve high-speed and high-density production without complicating the production process, reducing thermal transferability of dyes, adhesion between the dye layer and dye-receiving layer during transfer, and peeling of the dye layer. An object of the present invention is to provide a thermal transfer technology that can form images of

(Means for solving problems) The above objects are achieved by the present invention as described below.

That is, the present invention consists of two inventions, and the first invention is a thermal transfer sheet in which a dye layer is formed on the surface of a base film, wherein the dye layer contains a releasable silicone resin. In the second invention, a dye layer of a thermal transfer sheet having a dye layer formed on the surface of a base film and a receiving layer of an image receiving sheet having a dye receiving layer formed on the surface of the base film are stacked facing each other. , a thermal transfer method in which the dye layer contains a releasable silicone resin, in which the thermal transfer sheet is heated imagewise from the back side.

(Function) By including a specific silicone resin in the dye layer and preferably including a release agent in the dye-receiving layer,
The amount of release agent in each of the dye layer and the receptor layer can be reduced, making the production process more complicated, reducing the heat transferability of the dye, adhesion between the dye layer and the dye receptor layer during transfer, and peeling of the dye layer. Provided are a thermal transfer sheet and a thermal transfer method that can form high-density images at high speed without causing such problems.

(Preferred Embodiments) Next, the present invention will be described in more detail by citing preferred embodiments.

The base film of the thermal transfer sheet of the present invention may be any conventionally known film having a certain degree of heat resistance and strength, for example, a thickness of about 0.5 to 50 μm, preferably about 3 to 10 μm. paper, various processed papers, polyester film, polystyrene film, polypropylene film, polysulfone film, aramid film, polycarbonate film, polyvinyl alcohol film, cellophane, etc., and particularly preferred is polyester film.

When the base film as described above has poor adhesion to the dye layer formed on the surface, it is preferable to subject the surface to a brimer treatment or a corona discharge treatment.

The sublimable (thermally transferable) dye layer formed on the base film as described above is a layer in which a dye is supported by an arbitrary binder resin.

As the dye to be used, any dye used in conventionally known thermal transfer sheets can be effectively used in the present invention.
Not particularly limited. For example, some preferred dyes include MS Red G% Macro as a red dye.
lex Red Violet R, Ceres Re
d7B, Samaron Red HBSL, Re
Examples of yellow dye include Holon Brilliant Yellow 6GL%.
PTY-52, Macrolex Yellow 6G, etc., and blue dyes include Kaya Set Blue 14,
Examples include Vaxolin Blue AP-FW, Holon Brilliant Blue SR, MS Blue 100, and the like.

As the binder resin for supporting the heat-transferable dye as described above, any conventionally known binder resin can be used, and preferred examples include ethyl cellulose, droxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, Examples include cellulose resins such as methylcellulose, cellulose acetate, and cellulose acetate butyrate, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl and lolidone, vinyl resins such as polyacrylamide, and polyester. , cellulose-based, acetal-based, butyral-based, polyester-based, and the like are particularly preferred.

The silicone resins used in the present invention include, for example, epoxy-modified, long-chain alkyl-modified, alkyl-modified, amino-modified, carboxyl-modified, higher alcohol-modified, fluorofatty acid-modified, fatty acid-modified, alkyl aralkyl polyether-modified, epoxy polyether Modified silicone resins such as modified silicone resins and polyether-modified resins are desirable.

The structural formula of the example is shown below.

In the above formula, m is a numerical value from 1 to 100, and n is 1
The numerical value is from 50 to 50, R is the above-mentioned modifying group, and the molecular weight is preferably in the range of 300 to about io, ooo.

The above structural formula represents one example of the silicone resin used in the present invention, and the methyl group at the other end may be modified.

The above-mentioned silicone resin used in the present invention is known per se, and for example, F-907 (polyether modified, m=13.4.n=1.8.mp=52.
5°C), X-22-5050B (polyether modified, m=63
．． 5, n=2, mp=50.2°C), X-22-800
(Higher fatty acid modification, m=10, n=20, mp-68,
7°C), X-22-801B (alcohol denatured, m==5, n
= 19, mp = 64.4°C), KF-910 (higher fatty acid modified, m = 5, n = 13, m
p=65.2°C), X-24-3525 (fluorinated fatty acid modified), P-380
(long chain alkyl modification), X-22-3000E (epoxy modification), X-22-
It can be obtained and used commercially such as 3050C (amino modified).

The above silicone resins can be used alone or as a mixture, and the amount added is preferably 1 to 20 parts by weight per 100 parts by weight of the dye-forming resin. If the amount added is too small, the mold release effect will be insufficient, and if it is too large, the transferability of the dye and the strength of the film will decrease, and problems such as discoloration of the dye and storage stability will occur, which is not preferable.

The dye layer of the thermal transfer sheet of the present invention is basically formed from the above-mentioned materials, but may also contain various conventionally known additives as required.

Preferably, such a dye layer is prepared by adding the sublimable dye, silicone resin, binder resin, and other optional components in a suitable solvent and dissolving or dispersing each component to prepare a paint or ink for forming the dye layer. This is formed by coating and drying the above-mentioned base film film.

The dye layer formed in this way has a thickness of 0.2 to 5.0 μm,
The thickness is preferably about 0.4 to 2.0 μm, and the sublimable dye in the dye layer accounts for 5 to 90% of the weight of the dye layer.
Suitably it is present in an amount of 10% to 70% by weight.

The thermal transfer sheet of the present invention as described above may be provided with a heat-resistant layer on the back surface thereof in order to prevent adverse effects caused by the heat of the thermal head.

The image-receiving sheet used to form an image using the thermal transfer sheet as described above may be of any type as long as its recording surface has dye-receptive properties for the above-mentioned dyes. In the case of paper, metal, glass, synthetic resin film or sheet, etc., which do not have a dye-receiving layer, a dye-receiving layer may be formed on at least one surface thereof using a resin and a method as described below. In addition, such a dye-receiving layer has
It is preferable to include solid waxes such as known polyethylene wax, amide wax, and Teflon powder, fluorine-based or phosphate-based surfactants, silicone oil, and the like as mold release agents.

The thermal transfer image-receiving sheet used in the present invention consists of a base film and a dye-receiving layer provided on at least one surface of the base film.

The base films used include synthetic paper (polyolefin, polystyrene, etc.), high-quality paper, art paper, coated paper, cast coated paper, wallpaper, backing paper, synthetic resin or emulsion impregnated paper, synthetic rubber latex impregnated paper, Various plastic films or sheets such as synthetic resin-filled paper, paperboard, cellulose fiber paper, polyolefin, polyvinyl chloride, polyethylene terephthalate, polystyrene, polymethacrylate, polycarbonate, etc. can be used. A white opaque film formed by adding pigments or fillers, a foamed foam sheet, etc. can also be used, but there are no particular limitations.

Furthermore, a laminate made of any combination of the above base films can also be used. Typical examples of laminates include cellulose fiber paper and synthetic paper, or synthetic paper of cellulose fiber paper and plastic film or sheet. The thickness of these base films may be arbitrary, for example, 10 to 3
The thickness is generally about 00 μm.

When the base film as described above has poor adhesion to the receptor layer formed on the surface, it is preferable to subject the surface to a primer treatment or a corona discharge treatment.

The receiving layer formed on the surface of the base film is for receiving the sublimable dye transferred from the thermal transfer sheet and maintaining the formed image.

Examples of the resin for forming the dye-receiving layer include polyolefin resins such as polypropylene, halogenated polymers such as polyvinyl chloride and polyvinylidene chloride, vinyl polymers such as polyvinyl acetate and polyacrylic ester,
Polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polystyrene resins, polyamide resins, copolymer resins of olefins such as ethylene and propylene and other vinyl compounds, ionomers, cellulose resins such as cellulose diacetate, etc. , polycarbonate, etc., and particularly preferred are vinyl resins and polyester resins.

It is preferable to add a silicone resin to the receptor layer formed from the above resin, and the same silicone resins as mentioned above can be used.

The above silicone resin can be used alone or as a mixture, and the amount added is preferably 1 to 20 parts by weight per 100 parts by weight of the receptor layer forming resin. If the amount added is too small, the mold release effect will be insufficient, and if it is too large, the dye receptivity and film strength will decrease and it will be uneconomical.

The above-mentioned thermal transfer image-receiving sheet is prepared by dispersing the above-mentioned resin with necessary additives on at least one side of the above-mentioned base film, by dissolving it in a suitable organic solvent or dispersing it in an organic solvent or water. The dye-receiving layer is obtained by coating the dye-receiving layer by coating and drying it by a forming means such as gravure printing, screen printing, or reverse roll coating using a gravure plate.

When forming the above-mentioned receptor layer, pigments and fillers such as titanium oxide, zinc oxide, kaolin clay, calcium carbonate, and finely powdered silica are used to improve the whiteness of the receptor layer and further enhance the clarity of the transferred image. Can be added. or,
In order to further improve the resistance to change and fading of the transferred image formed on the receptor layer, especially the resistance to indoor change and fading and the resistance to dark place, ultraviolet absorbers and antioxidants can be added to the receptor layer.

The dye-receiving layer formed as described above may have any thickness, but numerically from 1 to 50 .mu.m. Although such a dye-receiving layer is preferably a continuous coating, it may also be formed as a discontinuous coating using a resin emulsion or resin dispersion.

Further, the image receiving sheet of the present invention can be applied to various uses such as thermal transfer recording sheets capable of thermal transfer recording, cards, transmission type manuscript preparation sheets, etc. by appropriately selecting the base film.

Furthermore, the above-mentioned image-receiving sheet can have a cushion layer between the base film and the receptor layer if necessary, and by providing such a cushion layer, images corresponding to the image information with less noise during printing can be produced. can be transferred and recorded with good reproducibility.

Examples of the material constituting the cushion layer include polyurethane resin, acrylic resin, polyethylene resin, butadiene rubber, and epoxy resin. The thickness of the cushion layer is preferably about 2 to 20 μm.

Moreover, a slippery layer can also be provided on the back surface of the base film. As the material of the slipping layer, methacrylate resin such as methyl methacrylate or corresponding acrylate resin,
Examples include vinyl resins such as vinyl chloride-vinyl acetate copolymer.

Furthermore, it is also possible to provide a detection mark on the image receiving sheet. The detection mark is extremely convenient when positioning the thermal transfer sheet and the image-receiving sheet, and for example, a detection mark that can be detected by a phototube detection device can be provided by printing on the back side of the base film.

The thermal transfer method of the present invention uses the thermal transfer sheet of the present invention, and the image-receiving sheet used may be a conventionally known one and is not particularly limited, but a preferable image-receiving sheet contains a release agent in its dye layer. This is an image-receiving sheet.

As the means for applying thermal energy during thermal transfer used in the method of the present invention, any conventionally known means can be used. Depending on the device,
5 to 100 by controlling the recording time.
The intended purpose can be sufficiently achieved by applying thermal energy of the order of m J/m.

(Effects) According to the present invention as described above, by incorporating a specific silicone resin into the dye layer and preferably incorporating a release agent into the dye-receiving layer, the release of each of the dye layer and the receptor layer is improved. The amount of molding agent can be reduced, making the production process less complicated.
A thermal transfer sheet, a thermal transfer image-receiving sheet, and a thermal transfer image-receiving sheet capable of forming high-speed and high-density images without causing a decrease in thermal transferability of a dye, adhesion between a dye layer and a dye-receiving layer during transfer, or peeling of a dye layer, etc. A thermal transfer method is provided.

(Example) Next, the present invention will be explained in more detail by giving examples and comparative examples. In the text, parts or percentages are based on weight unless otherwise specified.

Example 1 An ink composition for forming a dye layer having the following composition was prepared and applied using a wire bar to a 6 μm thick polyethylene terephthalate film whose back side had been heat-resistant treated so that the dry coating amount was 1.0 g/rn''. and dried to obtain a thermal transfer sheet (1) of the present invention.

Disperse dye (Kayaset Blue 14, manufactured by Nippon Kayaku) 4.
0 parts polyvinyl butyral resin (S-LEC BX-1, manufactured by Mikki Chemical) 4.3 parts fluorofatty acid modified silicone resin (X-24-3525, Shin-Etsu Kagaku Gen)
0.4 parts methyl ethyl ketone/
Toluene (weight ratio 1/1) 80.0 parts Isobutanol 10. Part O Example 2 The thermal transfer sheet of the present invention (2 ) was obtained.

Example 3 The thermal transfer sheet (3) of the present invention was obtained in the same manner as in Example 1 except that an epoxy-modified silicone (X-22-3000E, manufactured by Shin-Etsu Chemical Co., Ltd.) was used in place of the silicone resin in Example 1. Ta.

Example 4 A thermal transfer sheet (4) of the present invention was obtained in the same manner as in Example 1, except that a polyether-modified silicone resin (F-907, Shin-Etsu Kagaku Gen) was used in place of the silicone resin in Example 1. Ta.

Comparative Example 1 The thermal transfer sheet of Comparative Example (5
) was obtained.

Image receiving sheet A Synthetic paper (Yupo FRG-150, thickness 150 μm, manufactured by Tamago Yuka Co., Ltd.) was used as the base film, and 5.0 g of the coating liquid with the following composition was applied to one side of the paper using a bar coater when dry.
/m'' and dried to obtain a thermal transfer image-receiving sheet (A) used in the present invention.

Polyester (Vylon 600, Toyobo) 100 parts Epoxy-modified silicone (X-22-300B, Shin-Etsu Chemical) 5 parts Amino-modified silicone (X-22-3050C1, Shin-Etsu Chemical)
5 parts methyl ethyl ketone/toluene (weight ratio l/1) 100 parts Image-receiving sheet B A thermal transfer image-receiving sheet (B) prepared in the same manner as image-receiving sheet A except that the silicone resin in image-receiving sheet A was not used.
I got it.

The above-mentioned thermal transfer sheet and thermal transfer image-receiving sheet were stacked with their respective dye layers and dye-receiving surfaces facing each other, and a heat-sensitive sublimation transfer printer (VY-50, Newly manufactured by Hitachi Seisakusho) was used to print 90 m J/ Recording was performed with a thermal head from the back side of the thermal transfer sheet using a printing energy of m♂, and the results shown in Table 1 below were obtained.

1-f deficiency- Transfer sheet 1 C A Mold release property O Resolution O Discoloration of base material O A.A. OOO OOO Oo　O printed matter Preservability 0 △ Transfer sheet 1 2345 Seat BBBBB Mold release property 0000x Resolution ooooo.

Discoloration of base material　○　ooo.

Evaluation criteria: Release property: Manual peeling after printing O: Easy △: Slight adhesion Discoloration of large substrate: Visual observation of the non-printed area of the image receiving sheet after being left for one month O: No discoloration △: Slight discoloration : No discoloration Δ : Slight discoloration × : Discoloration to yellow Daisuke Sakaito Masu Kaede Toshita's bladder? ng

Claims (3)

[Claims] (1) A thermal transfer sheet having a dye layer formed on the surface of a base film, wherein the dye layer contains a releasable silicone resin. (2) The dye layer of a thermal transfer sheet with a dye layer formed on the surface of the base film and the receiving layer of an image receiving sheet with a dye receiving layer on the surface of the base film are stacked facing each other, from the back side of the thermal transfer sheet. A thermal transfer method in which the dye layer contains a releasable silicone resin, in which the dye layer contains a releasable silicone resin. (3) The thermal transfer method according to claim 2, wherein the dye-receiving layer contains a release agent.