JPS6164490A - Thermal transfer material - Google Patents

Abstract

PURPOSE:To obtain the close adhesiveness between heat-meltable ink and a support and to make it possible to hold the good thermal transfer property and resolving power possessed by a thermal transfer material, by containing liquid rubber in the heat-meltable ink. CONSTITUTION:The addition of liquid rubber to a heat-meltable ink layer contributes to the entancement of the flexibility of said ink layer and that of the close adhesiveness between said ink layer and a support. The liquid rubber is pref. contained in the heat-meltable ink layer in an amount of 0.1-2% in usual. If the content of the liquid rubber is below 0.1%, not only the good close adhesiveness between the heat-meltable ink layer and the support but also predetermined effect can not be obtained and, if exceeds 20%, the heat- meltable ink layer becomes sticky as a whole and causes contamination because a part of said ink layer is transferred to a recording medium even in a heat non-applied part by only the mere contact with said recording medium.

Description

[Detailed description of the invention] 1 Blood ±" The present invention has excellent adhesion between the support and the heat-melting ink layer,
The present invention also relates to a thermal transfer material that can provide a printed image with excellent thermal transferability and resolution.

L1 and 3 The thermal recording method, which is one of the recording methods, is not only noiseless, which is a feature of non-impact recording, but also easy to maintain, can be made smaller and lighter, and has relatively low running costs. Due to its features such as low energy consumption and low machine cost, it has recently come to be widely used in various fields such as facsimiles, computer terminals, and recorders. Color-forming thermal paper, which uses leuco dyes and phenolic compounds, is mainly used as the printing medium for these thermal recording devices, but it is expensive because it is processed paper, and records can be tampered with, and the recording paper can be heated. It has drawbacks such as being easily colored by organic solvents and organic solvents, recording images fading in a relatively short period of time, and recording having poor storage stability.

A recording method that has attracted attention in recent years in order to solve these drawbacks is the thermal transfer recording method. This involves preparing a thermal transfer material with thermal transferable ink coated on one side of the support, overlapping this ink-coated surface with a recording medium such as paper, and then using a thermal head from the opposite direction to the ink-coated surface of the thermal transfer material. A recorded image is formed by heating in a pattern and transferring ink to a recording medium by melting or sublimation according to the heating pattern.

The heat-melting ink provided on the support of the heat-sensitive transfer material is obtained by dispersing a colorant in a binder. When printing using such a heat-sensitive transfer material, if the adhesion between the heat-melt ink layer and the support is low, the heat-melt ink will peel off from the support even in areas where no heat is applied, resulting in non-stick properties of the recording medium. It adheres to the printed area and becomes a stain. More specifically, when the binder of the hot-melt ink is composed only of waxes, the adhesion between the hot-melt ink and the support is particularly low. The reason for this is thought to be that when the binder is only a wax, the ink layer is hard and crystalline and has poor flexibility, which reduces the adhesion between the hot-melt ink and the support. To solve this problem,
Conventionally, oils such as animal and vegetable oils and mineral oils have been blended into heat-melt inks as softeners, but when trying to obtain sufficient adhesion, the heat-melt ink becomes too flexible.
Conversely, the pressure of the thermal head transfers the non-heat-applied areas onto the recording medium, resulting in stains.In addition, a resin that is non-liquid at room temperature is used to increase the cohesive force of the ink layer. Although it is possible to improve the adhesion between the resin and the support, the melt viscosity increases and the thermal transferability, which is another printing property, decreases, making it impossible to obtain good printing.

In view of the above-mentioned circumstances, the present invention has been devised to provide a material that maintains the good properties of conventional thermal transfer materials, including thermal transferability and resolution, and has excellent adhesion between the support and the ink layer. , you can get clean prints. The purpose is to provide a thermal transfer material.

Iromamedate 1J In order to achieve these problems, the present inventors conducted research aimed at improving the adhesion between the heat-melting ink and the support, and as a result, they found that they included liquid rubber in the heat-melting ink. It has been found that extremely good adhesion between the heat-melting ink and the support can be obtained by this method, and the good thermal transferability and resolution of conventional thermal transfer materials can be maintained.

The heat-sensitive transfer material of the present invention is based on such knowledge, and more specifically, it is formed by forming a heat-melt ink layer on a support, and contains no liquid rubber in the heat-melt ink layer. ．．
It is characterized by being contained in a proportion of 1 to 20% by weight.

The present invention will be explained in more detail below. In the following description, "%" and "part" expressing quantitative ratios are based on weight unless otherwise specified.

: The heat-sensitive transfer material of the present invention is usually formed by forming a heat-melting ink layer on a sheet-like support (used to include a film), and its structure itself is different from that of conventional ones, in particular. It's not different.

As the support, conventionally known films and papers can be used as they are, such as films of relatively heat-resistant plastics such as polyester, polycarbonate, triacetyl cellulose, nylon, polyimide, cellophane, or sulfuric acid. Paper or the like can be suitably used. The thickness of the support is preferably about 2 to 15 microns, and the surface of the support that comes into contact with heat is coated with silicone resin, fluororesin, polyimide resin, epoxy resin, phenol resin, melamine resin, The heat resistance of the support can be improved by providing a heat-resistant protective layer made of nitrocellulose or the like, or it is also possible to use a support material that could not be used conventionally.

According to the present invention, the heat-melt ink layer on the support is formed by dispersing or dissolving a colorant in a heat-melt binder containing liquid rubber as an essential component.

The liquid rubber used in the present invention is a substance that is known per se and exhibits a liquid state at room temperature. Manufactured by thermal depolymerization, etc. More specifically, liquid polybutadiene rubber,
Included are liquid styrene-butadiene copolymer rubber, liquid butadiene-acrylonitrile copolymer rubber, liquid polychloroprene rubber, liquid polysulfide, liquid natural rubber, liquid polyisoprene, liquid butyl rubber, and the like. These have some differences in properties, such as whether they have curability or not, depending on whether or not they have residual functional groups; It contributes to improved flexibility and adhesion to the support, and has a remarkable effect on solving the above-mentioned problems such as peeling of conventional thermal transfer materials from the support and contamination of the recording medium. Demonstrate.

The liquid rubber is usually 0.1 to 20% in the heat-melting ink layer.
, preferably in a proportion of 1 to 10%, more preferably 3 to 5%.

If the content of liquid rubber is less than 0.1%, the desired effects such as good adhesion between the heat-melting ink layer and the support cannot be obtained, and if the content of liquid rubber is less than 20%. If the ink layer exceeds this value, the entire heat-melting ink layer becomes sticky, and even in non-heat-applied areas, a portion of the ink layer is transferred even when it comes into contact with the recording medium, causing stains.

The binder constituting the heat-melting ink layer has the liquid rubber as described above as an essential component, and is provided by combining this with a conventionally used heat-melting binder.

Heat-melting binders used for this purpose include natural vegetable waxes such as candelilla wax, carnauba wax, rice wax, Japanese wax, and jojoba oil;
Animal-based natural waxes such as beeswax, lanolin, spermaceti, etc.
Mineral natural waxes such as montan wax, osikelite, and ceresin; petroleum natural waxes such as paraffin wax, microcrystalline wax, and petrolatum; synthetic hydrocarbons such as Fischer-Tropsch wax and polyethylene wax; montan wax derivatives, paraffin wax derivatives, and microcrystalline waxes. Modified waxes such as wax derivatives, hydrogenated waxes such as hydrogenated castor oil and hydrogenated castor oil derivatives, fatty acids such as 12- and droxystearic acid, fatty acid amides such as stearic acid amide,
Alternatively, fatty acid esters, dialkyl ketones derived from higher fatty acids, and the like may be used alone or in combination of two or more.

Further, as the colorant, all dyes and pigments commonly used in printing or other recording methods can be used, and these can be used alone or in a mixture of two or more.

The thermal transfer material according to the present invention can be obtained, for example, as follows.

That is, the above-mentioned liquid rubber, hot-melt binder, colorant, and other additives added as necessary,
The colorant is sufficiently dissolved or dispersed by hot-melt kneading using a dispersing machine such as an attriter or a sand mill, and the colorant is hot-melt coated on a support using a conventional method, or the above-mentioned material is coated in an organic solvent. The hot-melt ink components are dissolved or dispersed and coated on a support with a solvent.

By the above operation, 0.5~l Ogm, preferably 2~l Ogm
A heat-sensitive transfer material having a heat-melting ink layer with a thickness of 6 pm is obtained.

The obtained thermal transfer material of the present invention is used in a thermal transfer recording method in substantially the same manner as conventional thermal transfer materials.

&"LQ"L button As is clear from the above, according to the present invention,
A heat-sensitive transfer material having a heat-melting ink layer formed by dispersing a colorant in a binder containing liquid rubber as an essential component is obtained. The heat-sensitive transfer material thus obtained has good adhesion between the heat-melting ink layer and the support, resulting in stain-free printing. Further, the addition of liquid rubber has less adverse effect on thermal transferability than conventional additives added to impart adhesion, and recording properties are maintained favorably.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Table 1 below (Liquid rubber in the table is for Examples 1 to 8.
Each of the ingredients shown in (respectively shown in section 2 below),
The mixture was placed in a sand mill maintained at 110° C. and sufficiently dispersed and mixed to obtain a heat-melting ink. This heat-melt ink was hot-melt coated on one side of a 6 pm thick polyethylene terephthalate film using a wire perforator.
A heat-sensitive transfer material having a heat-melting ink layer having a layer thickness of gm was obtained.

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Carbon black 10 Candelilla wax 20 (melting point near 2℃) Ceresin 7 (melting point = 89
℃) Microcrystalline wax 20 (melting point 296
℃) Paraffin wax 40 (melting point = 69
C) Rubber 2B+1 Table 3 Two types of thermal transfer materials were obtained in the same manner as in Examples 1 to 8, except that ink having the composition shown in Table 3 below was used instead of the composition shown in Table 1.

] Using the 10 kinds of heat-sensitive transfer materials thus obtained, a word processor, Cano Word 45S (manufactured by Canon Co., Ltd.) was used.
A printing test was conducted at a printing speed of 30 characters/sec, and the adhesion between the support and the hot-melt ink layer, staining on the recording medium after printing, transferability, and clarity were evaluated. The results are summarized in Table 4 below.

"clothing" In addition, evaluation of each item was performed as follows.

The test was carried out in accordance with ``L Characteristics RJ I S--5400-6,16 Pressure Resistance Flexibility'', and when no peeling of the ink layer on the support was observed, it was marked O, and when it was observed, it was marked X. did. The film thickness was 13 Bm, the diameter of the rod of the bending tester was 2 mm, and the thickness of the auxiliary plate was 4 mm. Separately, when printing was performed using a word processor Canoward 453 (manufactured by Canon Co., Ltd.), those marked with O did not peel off, and those marked with X showed stains due to peeling.

The recording material after printing was observed to determine whether there was any stain in the non-printed area.

(After printing, the heat-applied portion of the support in the heat-sensitive transfer material was observed to determine whether or not the heat-melting ink layer remained.

1. Observe the print on the top. If it is 1g bright, mark it as 0, and if it is not clear, mark it as X.
It was marked as a mark.

Looking at the results in Table 2, it can be seen that practical example 1 obtained according to the present invention
．． It can be seen that the heat-sensitive transfer material No. 2 has excellent adhesion between the support and the heat-melting ink layer, provides a stain-free recording medium, and also has good properties in terms of transferability and clarity. .

Claims (1)

[Claims] A heat-sensitive transfer comprising a heat-melt ink layer formed on a heat-resistant support, the heat-melt ink layer containing liquid rubber in an amount of 0.1 to 20% by weight. Material.