JPH02214696A - Thermal transfer recording material - Google Patents

Abstract

PURPOSE:To make many-time use possible by improving the close adhesiveness to an ink layer by providing at least a base material, an intermediate layer and an ink layer and containing a fine powder in the intermediate layer. CONSTITUTION:As a base material 1, a known film or paper can be used. An ink layer 3 has a composition wherein a colorant, a resin component and wax being a binder are mixed. The resin contained in an intermediate layer pref. has the strong close adhesiveness to the base material 1 and heat resistance of a certain degree and, as the fine particle 5 contained in the intermediate layer 2, an org. fine powder of carbon black, a metal such as aluminum, copper, nickel or tin and a metal compound such as aluminum oxide, magnesium oxide, tin oxide, calcium oxide or titanium nitride can be used alone or in a mixed state. By this method, the fixability of the intermediate layer and the ink layer is enhanced and no delamination is generated and stable printing is obtained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to thermal transfer recording materials that can be used multiple times.

[Prior Art] In recent years, thermal transfer recording materials have been used in many fields such as facsimiles, computer terminals, and recorders due to their characteristics such as non-impact, noiseless, maintenance-free, low cost, size and weight, and color printing. It is used.

Such a thermal transfer recording method melts and transfers ink onto a transfer paper by heating the surface of the recording material with a thermal head or by heating an energized heat-generating resistive layer with a current-carrying head.
It provides printing or images, and the general structure of thermal transfer recording materials includes a base material, a heat-resistant protective layer for preventing sticking, and a heat-melting ink layer.

However, when such a thermal transfer recording material is used for -degree printing, the ink layer in that area is transferred onto the transfer paper surface, making it impossible to print the same area multiple times.

Therefore, such disposable thermal transfer recording materials are extremely uneconomical.

In order to eliminate such uneconomical problems, JP-A-55-10
No. 5579, JP-A-57-185191, JP-A-60
40293 and Japanese Patent Application Laid-Open No. 63-137891, impregnating a porous resin matrix with hot-melt ink or providing a porous membrane on the hot-melt ink layer prevents ink from being removed during transfer. A technique has been devised to transfer the image onto a transfer paper. However, the density of the prints obtained is low, and high energy is required to obtain high-density prints, which poses problems such as problems with the heat resistance of the head or base material, and noticeable background stains on the transfer paper. Ta.

Japanese Patent Publication No. 56-89984, Japanese Patent Publication No. 57-36698
In order to strengthen the adhesion between the ink layer and the ink layer, an intermediate layer mainly composed of resin is provided on the base material, and a heat-melting ink layer is provided on top of the intermediate layer, as seen in the above-mentioned publications. A technology has been devised that allows for cohesive failure and multiple use.

[Problem to be solved by the invention]

However, in the structure of the thermal transfer recording material as described above, the affinity between the intermediate layer and the ink layer is weak, resulting in poor adhesion, which causes the ink layer to peel off at the interface of the intermediate layer, making cohesive failure unstable. The problem was that it was impossible to print multiple times.

The present invention has been made to solve the above-mentioned problems, and its purpose is to provide a thermal transfer recording material that has good adhesion with an ink layer and can be used many times.

[Means to solve the problem]

As a means for solving the above problems, the thermal transfer recording material of the present invention is characterized in that the thermal transfer recording material has at least a base material, an intermediate layer, and an ink layer, and the intermediate layer contains fine powder. do.

Furthermore, the fine powder is an organic fine powder such as carbon black, or a metal and/or a metal compound.

〔Example〕

Examples of the present invention will be described in detail below, but the present invention is not limited thereto.

FIG. 1 shows the structure of the thermal transfer recording material of the present invention.

As the base material 1, conventionally known films and papers can be used as they are, such as plastic films with relatively excellent heat resistance such as polyester, polycarbonate, triacetylcellulose, polyamide, polyimide, etc.
Cellophane, parchment paper, condenser paper, etc. can be used.

In this example, polyethylene terephthalate having a thickness of approximately 6 μm was used.

Next, as the components of the ink layer 3, the following coloring material, resin component, and wax as a binder are mixed to form the ink layer composition.

As the coloring material, pigments or dyes such as carbon black, Hansa Yellow G, brilliant carmine 6B, and phthalocyanine blue can be used.

On the other hand, resin components include polyethylene resins, polyamide resins, polyester resins, epoxy resins, polyurethane resins, polyolefin resins, which exhibit heat-melting properties,
Polyacrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, cellulose resin, polyvinyl alcohol resin, petroleum resin, polystyrene resin, rosin,
Ester gum, ethylene-vinyl acetate copolymer resin, ethylene ethyl acrylate, ethylene-α-olefin copolymer resin, α-olefin maleic anhydride copolymer resin,
Ethylene-methacrylic acid copolymer resin and the like can be used as appropriate.

Wax ingredients include whale wax, beeswax, lanolin,
Natural waxes such as carnauba wax, candelilla wax, montan wax, and secilene wax, petroleum waxes such as paraffin wax and microcrystalline wax, and synthetic waxes such as oxidized wax and Fischer-Tropsch wax can be selectively used.

The thickness of the ink layer 3 is preferably about 3 to 15 microns, and more preferably 5 to 10 microns.

If it is less than 3μ, the amount of ink transferred is small and multiple transfers cannot be performed, leading to a decrease in density and the generation of voids. On the other hand 15
If μ is exceeded, a large amount of transfer energy is required and clear transfer cannot be achieved.

In addition, when using a thermal head, the heat resistance of the base material 1 can be improved by providing a heat-resistant protective layer 4 made of silicone resin, fluorocarbon resin, epoxy resin, phenol resin, etc. on the surface of the base material 1 that comes into contact with the head. It can be improved.

In this example, the thickness of the layer mainly composed of silicone resin is approximately 0.
．． A heat-resistant protective layer 4 with a thickness of 2μ was provided.

Next, the composition of the resin included in the intermediate layer 2 is as follows:
It is preferable to use a resin that has strong adhesion with the resin and has some degree of heat resistance. For example, polyester resin, polyurethane resin, epoxy resin, polyvinyl butyral, polyisocyanate, phenol resin, etc. can be used. The thickness of the intermediate layer 2 is preferably about 0.2 to 5 .mu.m, more preferably 0.5 to 2 .mu.m. 0.2
If it is less than μ, the adhesion is weak, and if it exceeds 5μ, the ink layer 3
poor thermal conductivity.

Further, the fine particles 5 contained in the intermediate layer 2 are organic fine powders such as carbon black, metals such as aluminum, copper, nickel, and tin, aluminum oxide, magnesium oxide, tin oxide,
Metal compounds such as calcium oxide and titanium nitride can be used alone or in combination. The particle size of the fine powder 5 is as follows:
It is preferably 5μ or less, and more preferably 2μ or less. This is because if it exceeds 5μ, the adhesion with the ink layer 3 will be poor. Further, the mixing ratio of the resin of the intermediate layer 2 and the fine powder 5 is such that the weight of the fine powder 5 is preferably 5 to 70 wt%, more preferably 10 to 40 wt%.

When the amount is less than 5 wt%, the effect of fine powder 5 is not seen, and on the contrary, 7
If it exceeds 0 wt%, the adhesion will be poor.

(Example 1) First, an intermediate layer composition having the following composition was dispersed using a three-roll mill, and hot-melt coating was performed on a base material 1 to a layer thickness of about 1 μm to form an intermediate layer 2.

As the fine powder 5, carbon black having an average particle size of about 0.3 μm was used.

Intermediate layer composition Weight% fine powder 5
20 polyester
80 Next, on this intermediate layer 2, the ink layer components having the following composition are dispersed in a solvent, coated, and dried to a layer thickness of about 7.
An ink layer 3 of μ was formed.

Ink layer composition (self-solvent) Parts by weight Carbon black 55 Ethylene-vinyl acetate copolymer 30 Polystyrene resin
10 Paraffin Wax 5 Toluene 400 (Example 2) First, the intermediate layer composition shown below was dispersed using a three-roll mill, and then hot-melt coated onto the base material 1 so that the layer thickness was about 0.5μ. An intermediate layer 2 was formed. As the fine powder 5, aluminum oxide powder having an average particle size of about 0.05 μm was used.

Intermediate layer composition Weight% fine powder 5
10 polyethylene
90 Next, an ink layer 3 having the same composition as in Example 1 was formed on the intermediate layer 2 to a thickness of about 6 μm.

(Example 3) First, an intermediate layer composition having the following composition was dispersed using a three-roll mill, and hot-melt coating was performed on the base material 1 to a layer thickness of about 2 μm to form an intermediate layer 2.

The fine powder 5 used was a mixture of carbon black having an average particle size of about 0.05 μm and nickel powder having an average particle size of 0.1 μm in a ratio of 2:1.

Intermediate layer composition Weight% fine powder 5
25 Ethylene-vinyl acetate copolymer 75 Next, an ink layer 3 having the same composition as in Example 1 was formed on the intermediate layer 2 to a thickness of about 5 μm.

(Comparative Example 1) First, the intermediate layer 2 of polyester resin was formed on the base material 1 to have a thickness of about 1 μm.

Next, an ink layer 3 having the same composition as in the example was formed on the intermediate layer 2 to a thickness of about 7 microns.

As described above, the thermal transfer recording materials prepared in Example 1.2.3 and Comparative Example 1 were printed at the same location five times using a thermal printer, and the quality of the printing was visually evaluated. The transfer paper used was thermal paper with a Beck smoothness of about 300 sec and Xerox 4024 paper with a Beck smoothness of 40 SeC. Table 1 shows the results of the print quality obtained. In addition, ◎, 01Δ, and × in the table are visual evaluations that indicate grades from best to poor.

Table 1. Print Quality As explained above, the present invention can improve the adhesion between the intermediate layer and the ink layer by containing organic fine powder such as carbon black, metal, or metal oxide in the intermediate layer. , layer peeling between the ink layer and the intermediate layer will not occur,
This has the effect of providing stable printing.

[Brief explanation of the drawing]

FIG. 1 is a structural diagram showing a cross section of the thermal transfer recording material of the present invention. FIG. 2 is a structural diagram showing a cross section of a conventional thermal transfer recording material. As is clear from the above results, the thermal transfer recording material containing the fine powder 5 in the intermediate layer 2 has excellent adhesion between the intermediate layer 2 and the ink layer 3, and can perform stable transfer regardless of whether it is special paper or plain paper such as 4024 paper. It was showing. On the other hand, in a thermal transfer recording material that does not contain fine powder 5, especially when transferred to plain paper, the ink layer 3 becomes the intermediate layer 2.
It peeled off and stable printing could not be obtained. [Effects of the invention] ・Base material, intermediate layer, ink layer, heat-resistant protective layer, fine powder or more Procedural amendment (voluntary)

Claims (1)

[Scope of Claims] (1) A thermal transfer recording material having at least a base material, an intermediate layer, and an ink layer, characterized in that the intermediate layer contains fine powder. (2) The thermal transfer recording material according to claim 1, wherein the fine powder is an organic fine powder. (3) Claim 2, wherein the organic fine powder is carbon black.
The thermal transfer recording material described. (4) The thermal transfer recording material according to claim 1, wherein the fine powder is a metal and/or a metal compound.