JP2511450B2 - Thermal transfer recording medium - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thermal transfer recording medium for performing thermal transfer recording on a recording paper by utilizing the thermal melting property of an ink layer, and a printer such as a computer and a word processor, and a barcode. It can also be applied to printers and the like.

[Prior Art] A thermal transfer medium in which a transfer layer composed of a heat-fusible substance such as paraffin wax and a coloring agent such as a dye or a pigment is provided on a support is known. Paraffin waxes have a mechanical strength. Has a drawback that the transferred image is inferior in abrasion resistance.

In order to improve this drawback, a method of adding a thermoplastic resin or making the transfer layer as thin as possible is taken, but in the former case, if the resin component increases, the adhesive strength becomes strong and it becomes difficult to transfer, There is a problem that the sensitivity is deteriorated, and the latter has a problem that the uniformity of the transferred image is deteriorated and the image density is lowered. Further, in order to prevent the adhesive force from becoming strong even if the amount of the resin component is large, a water- or solvent-dispersed particulate ink has been studied, but if the particle property is too strong, there is a problem that the thermal sensitivity deteriorates.

[Purpose] The present invention solves the above-mentioned problems of the prior art, and can obtain a transferred image having high density and excellent uniformity on a recording paper, and further, a thermal transfer capable of obtaining a transferred image having excellent abrasion resistance. The purpose is to provide a recording medium.

[Structure] The thermal transfer recording medium of the present invention for achieving the above object has the following structure.

Support, colorant provided on the support, water-insoluble resin,
A thermal transfer recording medium comprising a thermal transfer ink layer mainly composed of wax, wherein the thermal transfer ink layer contains a morpholine fatty acid salt having the following structure.

(R represents a hydrocarbon group having 10 to 21 carbon atoms.) That is, in the present invention, by incorporating a morpholine fatty acid salt in the thermal transferable ink layer, a part of the ink is solubilized and the particle property is moderated. To improve transferability and abrasion resistance. Further, when the morpholine fatty acid salt is contained in the thermal transferable ink layer in the vicinity of the surface facing the transfer-receiving paper, scratch resistance can be improved, which is more preferable.

From the above-mentioned thermal transfer recording medium of the present invention, the thermal transferable ink layer can be overlaid on the transfer paper, and a desired image can be formed on the recording paper by thermal printing from the back surface of the thermal transfer recording medium.

As the support of the thermal transfer recording medium in the present invention, various conventionally known supports can be appropriately used.

Examples thereof include a polyester film, a polyamide film, a polyvinyl chloride film, a polyethylene film, a polypropylene film, a polyimide film, a polysulfone film, a plastic film such as a polycarbonate film, or a condenser paper.

As the colorant used in the present invention, inorganic and organic dyes and pigments used in printing inks, paints and the like can be used. Specific examples include carbon black, disazo yellow, brilliant carmine 6B, lake red C, phthalocyanine blue, Kayaset Black KR (Nippon Kayaku), Oil Yellow 3G (Orient Science), Kayaset Red K-BE (Nippon Kayaku), Kayaset Blue KFL (Nippon Kayaku) and others are available.

For water-insoluble resin, melting point or softening point (ring and ball method JI
SK 2531) Various resins of 60 to 140 ℃ can be used. For example, acrylic resin, methacrylic resin, styrene resin, vinyl acetate resin, vinyl chloride resin, vinylidene chloride resin, petroleum resin, novolac resin, olefin resin, polyester resin, polyacetal resin, terpene resin, rosin resin, epoxy prepolymer, or These include copolymers.

Furthermore, a plasticizer may be used, if necessary, to adjust the melting point or softening point of the water-insoluble resin. For example, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, di-2-ethylhexyl adipate, diethylene glycol dibenzoate, butyl stearate, triphenyl phosphate and the like.

If the water-insoluble melting point or softening point used in the thermal transfer ink layer is lower than 60 ° C, the high temperature environment (50-60
Friction resistance at (° C) deteriorates, and if it is higher than 140 ° C, it is difficult to sufficiently fix with the energy for thermal transfer recording alone, and the friction resistance is inferior. Otherwise, high energy recording is required, and the recording speed is high. Problems such as slowing down and shortening the life of the thermal head occur.

The water-insoluble resin used in the present invention is obtained by atomizing various resins (emulsion polymerization, wet milling method by sand mill, ball mill, etc.,
There is a dry dispersion method using a jet mill or the like).

The average diameter of the water-insoluble resin is preferably 10 μm or less, more preferably 5 μm or less. If it exceeds 10 μm, heat sensitivity and resolution are deteriorated, which is not preferable.

The amount of these water-insoluble resins used affects thermal sensitivity and abrasion resistance of a thermal transfer image. The amount of the water-insoluble resin used is preferably 10 to 80% by weight of the total solid content of the transfer layer, and 80% by weight.
If it exceeds 10%, a uniform transferred image cannot be obtained, and if it is less than 10% by weight, abrasion resistance is deteriorated, which is not preferable.

A wax having a melting point or a softening point of 70 to 130 ° C. is suitable for the wax used in the present invention.

If the melting point or softening point of the wax is lower than 70 ° C., the applied heat energy is consumed for melting the wax, and the energy for softening the resin is insufficient. Therefore, only the wax is transferred preferentially, the transfer of the transfer layer is insufficient, and the transferred image is blurred and the sharpness is lowered. Further, if the temperature is higher than 130 ° C, high heat energy is required for transfer.

Further, the penetration of such a wax is 5 or less at 25 ° C. according to the measuring method according to JIS K 2530, and if the penetration is larger than 5, the scratch resistance of a recorded image is deteriorated.

Specific examples include carnauba wax, polyethylene wax, Fischer-Tropsch wax, montan wax derivative, hydrogenated castor oil and the like.

The amount of these waxes used affects the thermal sensitivity and the abrasion resistance of the thermal transfer image. The amount of wax used is preferably 10 to 80% by weight based on the total solid content of the transfer layer. If it is less than 10% by weight, a uniform transferred image cannot be obtained, and if it exceeds 80% by weight, abrasion resistance is deteriorated, which is not preferable. .

Fatty acids constituting the morpholine fatty acid salt used in the present invention
RCOOH has 4 to 30 carbon atoms such as oleic acid, stearic acid, palmitic acid, myristic acid,
Behenic acid etc. The proportion of morpholine fatty acid salt used is 0.5 to 10% of the total solid content of the heat transferable ink layer. If it is less than 0.5, an excellent transferred image cannot be obtained, and if it exceeds 10%, the abrasion resistance is deteriorated.

Other additives such as water-soluble resins and surfactants can also be used in the thermal transfer ink of the present invention.

The water-soluble resin is a binder of the thermal transfer ink, and its usage rate is 2 to 20% by weight of the total solid content of the thermal transfer ink.
Is good. If it is less than 2% by weight, the binding property of the thermal transfer ink is poor, and if it exceeds 20% by weight, the transfer property is poor. Specific examples thereof include polyvinyl alcohol, methoxy cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, polyvinyl pyrrolidone polyacrylamide, starch, gelatin and the like.

The surfactant is a dispersion liquid stabilizer for the heat transferable ink, and its use ratio is preferably 5% by weight or less based on the total solid content of the heat stable ink. If it exceeds 5% by weight, stickiness increases. The surfactant may be any of nonionic surfactants, cationic surfactants, anionic surfactants and amphoteric surfactants. Specific examples of the cationic surfactant include octadecyl amine acetate, alkyl (hardened tallow) trimethyl ammonium chloride, polyoxyethylene octadecyl amine, polyoxyethylene (tallow) amine, and high molecular amine. As the anionic surfactant, fatty acid soda soap, fatty acid potassium soap,
Sodium stearate, alkyl ether sulphate (Na salt), sperm alcohol, sodium sulfate ester, sodium dodecylbenzene sulfonate, sodium alkyl (beef tallow) methyl taurate, sodium oleoyl methyl taurate, sodium dioctyl sulfosuccinate, high molecular type Anion etc. are mentioned. As the nonionic surfactant, polyoxyethylene oleyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, polyoxyethylene nonylphenol ether, polyoxyethylene octylphenol ether, polyoxyethylene monolaurylate, Polyoxyethylene monostearate, polyoxyethylene monooleate, polyethylene glycol, tallow fatty acid ester, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, sorbitan trioleate, Polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monostearate, Polyoxyethylene sorbitan monooleate, polyoxyethylene oxypropylene block polymer, glycerol monostearate, polyoxyethylene distearate, and the like. Examples of the amphoteric surfactant include dimethylalkyl (coconut) betaine.

As the transfer paper used with the thermal transfer recording medium of the present invention, plain paper, synthetic paper, plastic film and the like can be appropriately used.

In the thermal transfer recording medium of the present invention, the above-mentioned thermal transferable ink layer forming component is mixed with water or a solvent which does not dissolve it in an appropriate method, and the average particle size of the forming component is adjusted by a dispersing means such as a stirrer, a ball mill and an attritor. Disperse it to 10 μm or less, apply it on a support so that the total solid content is 1 to 10 g / m ² , and soften the components so that they will not be fused. It can be produced by drying at a temperature below the point.

EXAMPLES Next, the present invention will be described in more detail with reference to examples. In addition, "part" and "%" shown below are based on weight.

(1) Preparation of carbon black dispersion The compositions shown in Table 1 were dispersed in a ball mill for 24 hours to prepare a carbon black dispersion.

(2) Preparation of water-insoluble resin dispersion The compositions shown in Table 2 were dispersed in a ball mill for 24 hours to prepare a water-insoluble resin dispersion liquid.

(3) Preparation of wax dispersion The compositions shown in Table 3 were dispersed in a ball mill for 24 hours to prepare a wax dispersion liquid.

(4) Preparation of coating liquid for forming thermal transferable ink layer Coating liquids No. 1 to 6 for forming thermal transferable ink layer were prepared by uniformly mixing the compositions shown in Table 4 with a stirrer.

Example 1 The coating solution No. 1 was applied onto a 6 μm thick polyester film using a wire bar so that the amount of adhesion after drying was 2 g / m ² , and dried with warm air (40 to 50 ° C.). .

Next, the coating amount after coating liquid No. 4 on the coating surface is dried
A thermal transfer recording medium was prepared by coating and drying in the same manner to ² g / m ² .

Examples 2 to 5 Thermal transfer recording media were prepared in the same manner as in Example 1 except for the combination of coating liquids. Table 5 shows combinations of coating solutions together with Example 1.

Example 6 In Examples 1 to 5 above, since the morpholine fatty acid salt is contained only in the surface of the thermal transfer recording medium in the vicinity of the transfer paper, two types of coating liquids, a liquid containing the fatty acid salt and a liquid not containing the same This example illustrates the case where only a coating solution containing a morpholine fatty acid salt is used.

That is, coating solution No. 5 was applied to a 6 μm thick polyester film so that the amount of adhesion after drying was 4 g / m ² , and dried to prepare a thermal transfer recording medium.

Comparative Examples 1 and 2 Coating solutions No. 2 and No. 6 were processed in the same manner as in Example 6 to prepare a thermal transfer recording medium.

Comparative Examples 3 and 4 In the same manner as in Examples 1 to 5, coating solutions shown in Table 6 below were combined to prepare thermal transfer recording media.

Using the thermal transfer recording medium produced as described above, bring the transfer layer into close contact with the surface of the high quality paper and use a thermal transfer printer.
Printing was performed by applying energy of 0.5 mJ / dot. Furthermore, in order to examine the abrasion resistance of the printed image, use a lab tester (manufactured by Toyo Seiki Co., Ltd.)
0 ° C) was tested.

 The results are shown in Table 7 below.

[Effect] As is apparent from the above description, the thermal transfer recording medium of the present invention can obtain a transferred image having high density and excellent uniformity, and is also excellent in abrasion resistance and scratch resistance. It has a great effect.

Claims (2)

(57) [Claims] 1. A thermal transfer ink layer mainly comprising a support, a colorant provided on the support, a water-insoluble resin and a wax, wherein the thermal transfer ink layer contains a morpholine fatty acid salt having the following structure. A thermal transfer recording medium characterized in that (R represents a hydrocarbon group having 4 to 30 carbon atoms) 2. The thermal transfer recording medium according to claim 1, wherein the morpholine fatty acid salt is contained in the thermal transfer ink layer in the vicinity of the surface facing the transfer paper.