JPH02112991A - Heat transfer image receiving sheet - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (I. Field of Industrial Application) The present invention relates to a thermal transfer image-receiving sheet, and more specifically, a thermal transfer image-receiving sheet that can form a recorded image with improved color density, resolution, sharpness, etc. The purpose is to provide an image receiving sheet.

(Prior art and its problems) Conventionally, various thermal transfer methods have been known. j1) Transferring material that can be dyed with a synthetic dye, such as polyester woven fabric, etc.
A sublimation transfer method is used in which thermal energy is applied in a pattern from the back side of a thermal transfer sheet to transfer a sublimable dye to a transfer material.

In the above-mentioned sublimation printing method, in which the material to be transferred is, for example, polyester woven fabric, the application of thermal energy is relatively long, so the material to be transferred itself is also heated by the applied thermal energy. As a result, relatively good dye migration was achieved.

In addition, we use a transfer material with a dye-receiving layer made of polyester resin, etc., which has good dye-dyeability, and use a thermal head to print delicate letters, graphics, or photographs on stiff transfer materials at high speed. A method of forming an image has been proposed. In this case, the application of thermal energy is required to be extremely short, on the order of seconds or less, and therefore, in order to sufficiently transfer the dye to the receiving layer in such a short time, the thermal head must be heated with high heat. It is necessary to supply energy.

However, when high heat is applied to the thermal head, the dye layer of the thermal transfer sheet and the receptor layer of the transfer material adhere to each other, and when the two are peeled off, the dye receptor layer peels off from the base sheet, making it impossible to form a satisfactory image. The problem is that you can't get it.

Therefore, an object of the present invention is to provide a thermal transfer method using a sublimable dye, in which the dye-receiving layer does not peel off from the base sheet even when high thermal energy is applied, and clear images with sufficient density and resolution can be obtained. It is an object of the present invention to provide a heat transfer η image receiving sheet that provides a thermal conversion η.

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

That is, the present invention is characterized in that it comprises a base sheet and a dye-receiving layer formed on at least one surface of the base sheet, and the dye-receiving layer is mainly formed of a polyester resin having a branched structure. This is a thermal transfer image-receiving sheet.

(Function) By forming the dye-receiving layer of the thermal transfer image-receiving sheet mainly from polyester resin with a branched structure, the dye-receiving layer does not peel off from the base sheet even when high thermal energy is applied, and it maintains sufficient density and resolution. A thermal transfer image-receiving sheet is provided which provides a clear image with imageability.

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

The thermally transferred Z) image-receiving sheet of the present invention consists of a base sheet and a dye-receiving layer provided on at least one surface of the base sheet.

The base sheet used in the present invention includes synthetic paper (polyolefin, polystyrene, etc.), polyolefin, polyvinyl chloride, polyethylene terephthalate, polystyrene, polymethacrylate, polycarbonate, and other various plastic films or sheets. The surface is smooth and the adhesion of the receptor layer forming resin is insufficient. Of course, base sheets such as various types of paper may also be used. Particularly useful in the present invention is a polyethylene terephthalate film. Furthermore, a laminate made of any combination of the above base sheets can also be used.

The receptor layer formed on the surface of the base sheet is for receiving the dye that migrates from the thermal transfer sheet and maintaining the formed image.

The present invention is characterized in that the above-mentioned receptor layer is formed mainly from a branched polyester resin.

Branched polyester resin refers to polycarboxylic acids with trifunctionality or higher as part of the acid component or polyols with trifunctionality or higher as part of the alcohol component when producing linear polyester from dicarboxylic acid and diol. This can be obtained by

Examples of the dicarboxylic acid 5 used in the present invention include phthalic acid, isophthalic acid, terephthalic acid, 1.2-11.
4-11.5-11,6-11゜7-or 1.8-naphthalenedicarboxylic acid, diphenyl-2,2',2,3
', 2.4'3.3', 4,4'-dicarboxylic acid, diphenylmethane-2,2', 2,3', 2,4', 3゜3
', 4.4'-Cicalphoic acid, diphenyl ether-
4,4'-dicarboxylic acid, hensifhenone-4,4'-
Dicarboxylic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, adipic acid, succinic acid, maleic acid,
Examples include sebacic acid, isosebacic acid, dimer acid, tetrachlorophthalic acid, 4,4'-dicarboxy-diphenylmethane, and 4,4'-dicarboxycyphenylpropane. Particularly preferred are isophthalic acid, terephthalic acid or derivatives thereof.

3 (Examples of polycarboxylic acids with lfi or higher include trimellitic acid, trimesic acid, 1.2°5-12
, 3,6- or 1.8.4-naphthalenetricarboxylic anhydride, 3,4.4'-diphenyltricarboxylic anhydride, 3,4.4''-diphenylmethanetricarboxylic anhydride, 3゜4 Examples include 4'-diphenyl ether tricarboxylic anhydride and 3,4,4''-benzophenone tricarboxylic anhydride, and trimellitic acid is particularly useful. Of course, derivatives such as esters and anhydrides of the above-mentioned di- or polyacids may also be used.

Examples of diols include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol, dipropylene glycol, 1°3-propanediol, various butane-, pentane-5- or hexanediols, e.g. , 1.3- or 1.4-butanediol, 1.5-bentanediol, 1.6-hexanediol, 1,4-butene-2-diol, 2.2-dimethylpropanediol-1,3,2 -ethyl-2-butyl-propanediol-1,3,1,4-dimethylolcyclohexane, 1
．． 4-butynediol, water-added bisphenols (e.g., water-added P, P'-dihydroxydiphenylpropane or its homologues), cyclic glycols, e.g. 2,2
, 4゜4-tetramethyl-1,3-cyclobutanediol, hydroquinone-cyβ-hydroxyethyl-ether, 1,4-cyclohexane dimetatool, 1,4-cyclohexane jetanol, trimethylene glycol,
Examples include hexylene glycol and octylene glycol. Particularly preferred are ethylene glycol, 1.
2-propylene glycol and 1,6-hexanediol.

Examples of trivalent or higher polyols include glycerin, 1,1.1-trimethylolethane, 1,1.1-
Examples include trimethylolpropane, and particularly preferred is glycerin.

The branched polyester resin used in the present invention is produced by a conventional method from the above-mentioned components, and the trivalent or higher polycarboxylic acid or polyol used at this time has a content of about 0.5 to 50% of the acid component or alcohol component. It is preferable to use it in a proportion accounting for equivalent %, preferably 1.0 to 10 equivalent %, to form a branched structure.

If the amount of polycarboxylic acid or polyol used is too small, the adhesiveness of the obtained polyester resin to the base sheet will be insufficient, while if it is too large, gelation will occur, making it unusable, which is not preferable.

The thermal transfer image-receiving sheet of the present invention is prepared by dissolving a branched polyester resin as described above or a mixture thereof with other resins in an appropriate organic solvent on at least one side of a base sheet having a surface profile. A dye-receiving layer can be obtained by coating and drying a dispersion in water.

When using a mixture of branched polyester resin and other resins, the branched polyester resin or
% or more, preferably 10% or more by weight.

When forming the above-mentioned receptor layer, titanium oxide, lll1 lead oxide, kaolin clay, calcium carbonate,
Pigments and fillers such as finely powdered silica can be added. Further, in order to further increase the light resistance of the transferred image, an ultraviolet absorber and/or a light stabilizer may be added to the receiving layer.

Such a dye-receiving layer may be any suitable material, but the thickness within the membrane is between 3 and 50 .mu.m. Further, although such a dye-receiving layer is preferably formed as a continuous coating, it may be formed as a discontinuous coating using a resin emulsion or a resin dispersion.

The heat-transformable γI image-receiving sheet of the present invention can basically be used with the above structure, but it is also possible to incorporate an inorganic powder for preventing adhesion into the dye-receiving layer.
In this way, even if the temperature during thermal transfer is increased, adhesion between the thermal transfer sheet and the thermal transfer image-receiving sheet can be prevented and even better thermal transfer can be performed. Particularly preferred is
It is finely powdered silica.

Furthermore, in place of or in combination with the above-mentioned inorganic powder such as silica, a resin having good an ``+'! For example, a cured product consisting of an epoxy-modified silicone oil and an amine-modified silicone oil may be mentioned.

Such a release agent preferably accounts for about 0.5 to 30% by weight of the dye-receiving layer.

The thermal transfer sheet used when carrying out thermal transfer using the thermal transfer image-receiving sheet of the present invention as described above is one in which a dye layer containing a sublimable dye is provided on paper or polyester film, and conventionally known thermal transfer sheets are Any of them can be used as is in the present invention.

According to the research of the present inventor, the dye used in the thermal transfer sheet has at least one primary to tertiary amino group.
It has been found that the best image can be formed when the dye is preferably an indoaniline dye, a cyanoacetyl dye, or an anthraquinone dye.

Furthermore, as a means for applying thermal energy during thermal transfer, any conventionally known means can be used, such as a thermal printer (for example,
By controlling the recording time using a recording device such as 00), it is possible to sufficiently achieve the desired purpose by applying thermal energy of about 5 to +00 mJ/mm'.

(Effects) According to the present invention as described above, by forming the dye-receiving layer of the thermal transfer image-receiving sheet from a polyester resin with a branched structure, even when high thermal energy (=1) is applied, the dye-receiving layer does not change to the base material sheet. Provided is a thermal transfer image-receiving sheet that does not peel off from the surface and provides a clear image with sufficient density and resolution.

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

Reference Example 1 Terephthalic acid 66 parts (4 equivalents) Isophthalic acid 100 parts (6 equivalents) Ethylene glycol
28 parts (4,5 equivalents) trimethylolpropane 7 parts (05 equivalents) Hisphenol A 114 parts (5 equivalents 11) were placed in a reaction vessel, and the mixture was heated in a nitrogen gas atmosphere using antimony trioxide as a catalyst for 3 hours. The temperature was raised to 150°C, reacted at this temperature for 1 hour, and further heated to 275°C with a reaction temperature of 0.1 to 0.15.
The branched polyester resin was mixed with dehydrated cotton under condition F of mmHg for 2 hours.

Reference Example 2 A branched polyester resin was obtained in the same manner as in Reference Example 1 using the following components.

Terephthalic acid 83 parts (5 equivalents'jL) Isophthalic acid 66 parts (4 equivalents) Trimellitic acid 21 parts (1 equivalent) Ethylene glycol
31 parts (5 parts 111) Bisphenol A 68
parts (3 parts 1 part) Propylene glycol 15 parts (2 equivalents) Reference example 3 Terephthalic acid 66 parts (4 parts) Isophthalic acid 66 parts (1 part 4) [・Limelitic acid
42 parts (2 parts [4) ethylene glycol
25 parts (4 equivalents) trimethylolpropane 13 parts (
I MffH Bisphenol A 114 parts (5 equivalents) Comparative Reference Example 1 A branched polyester resin was obtained in the same manner as in Reference Example 1 using the following components.

Terephthalic acid 66 parts (4 equivalents) Isophthalic acid 66 parts (4 equivalents Gt) Sepatic acid
40 parts (2 equivalents) ethylene glycol 31
Parts (5 parts) Bisphenol A 46 parts (2 parts) Propylene glycol 23 parts (3 parts 111 parts) Examples 1 to 3 and Comparative Example 1 Polyethylene terephthalate film as base sheet (% T-100, 100 μm) Apply a coating solution with the following composition to one side using a bar coater when drying.
．． The thermal transfer image-receiving sheets of the present invention and comparative examples were obtained by coating at a rate of 0 g/m' and drying.

When the peeling force of the receiving layer of these image receiving sheets was measured, the results shown in Table 1 below were obtained.

Polyester 100 of Reference Examples 1 to 3 or Comparative Reference Example 1.
0 parts epoxy-modified silicone (X-22-3000E, manufactured by Shin-Etsu Chemical) 8 parts amine-modified silicone (X-22-3050G, manufactured by Shin-Etsu Chemical) 8 parts methyl ethyl ketone/toluene (weight ratio 1/1) 400 parts, An ink composition for forming a dye-supporting layer having the following composition was prepared, and a dry coating amount of 1.0 g/rn' was applied to a 6 μm thick polyethylene terephthalate film whose back side was heat-resistant treated.
A thermal transfer sheet was obtained by coating and drying with a wire bar so as to obtain a heat transfer sheet.

c, r, Disbirds Blue 24 1.0 parts Polyvinyl butyral resin 10.0 parts Methyl ethyl ketone/toluene (heavy! Tsuji ratio l/1) 90.0 parts The above thermal transfer sheet and the thermal transfer of the present invention and comparative example described in 1 Ifr The image-receiving sheet was nailed together with each dye layer and dye-receiving surface facing each other, and printing was performed using a thermal head from the back side of the thermal transfer sheet under conditions of a head applied voltage of 120 V, a pulse width of 16 a+sec, and a dot density of 6 dots/line. The resolution of the obtained images was compared, and the results shown in Table 1 below were obtained.

γ”!；　　　　　　　　　　--Z Example 1 Example 2 Actual h’B example 3 Comparative example 1

Claims (3)

[Claims] (1) A thermal transfer image receptor comprising a base sheet and a dye-receiving layer formed on at least one surface of the base sheet, and the dye-receiving layer is mainly formed of a polyester resin having a branched structure. sheet. (2) The thermal transfer image-receiving sheet according to claim 1, wherein the branched polyester is produced in the presence of a polycarboxylic acid or a polyol having a valence of 3 or more. (3) The thermal transfer image-receiving sheet according to claim 1, wherein the polycarboxylic acid or polyol accounts for 0.5 to 50 equivalent % of the acid component or alcohol component.