JPH0377077B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a thermal recording head to heat a transfer layer provided on the lower surface of a transfer sheet and transfer it to a recording medium such as paper, plastic, or metal foil, thereby recording. In the heat-sensitive recording material used in the heat-sensitive transfer recording method, the transfer layer contains a vinyltoluene/butadiene copolymer resin with a melting point or softening point in the range of 60°C to 150°C and a coloring agent such as a disperse dye or a colored pigment. The present invention relates to a heat-sensitive transfer type recording material containing the above.

Recently, various recording sheets have been researched, developed, and put into practical use in the field of information recording, in response to social demands such as diversification and increase in information, resource conservation, and pollution-free society. Among these, thermosensitive recording materials (1) record a colored image simply by heating, eliminating the need for a complicated development process, (2) are relatively simple and compact devices, and the resulting recording material is easy to handle. (3) Paper is often used as a support, and in this case, not only is the support cost low, but the feel of the resulting recording material is similar to that of plain paper. Because of these advantages, it is widely used in the fields of computer output, printers such as calculators, recorders for medical measurement, facsimiles, automatic ticket vending machines, thermal copying, etc.

As the heat-sensitive recording materials commonly used here, dye coloring type or metal compound type are known. Among these, many utilize the reaction between leuco dyes and bisphenols due to their advantages such as less background fog and clear colored images. However, recently, the reliability of images has become a problem, especially the decolorization and falsification of images caused by organic solvents and plasticizers. A thermal transfer recording method for obtaining a transferred image on plain paper using a transfer sheet of thermal transfer recording material has also been proposed and put into practical use. This thermal transfer recording material is satisfactory in that there is no background fogging or decoloring of the image, but due to contact between the transfer layer of the transfer sheet and the recording material, there are problems such as background staining, transfer stability, resolution of the transferred image, etc. However, the quality is still not satisfactory.

Therefore, in order to solve the above drawbacks, the inventors of the present invention
As a result of extensive research, we have found that the transfer layer of the transfer sheet contains a vinyltoluene/butadiene copolymer resin and a colorant, which has excellent abrasion resistance.
Furthermore, the present inventors have discovered that a heat-sensitive transfer type recording material without fear of tampering can be obtained, and have completed the present invention.

That is, according to the present invention, in a thermal recording material used in a thermal transfer recording method in which a recording is obtained by transferring a transfer layer of a transfer sheet to a recording material using a thermal head, the transfer layer has a melting point or softening point. 60
There is provided a heat-sensitive transfer type recording material characterized in that it contains a vinyltoluene/butadiene copolymer resin and a colorant having a temperature in the range of 150°C to 150°C.

The vinyltoluene/butadiene copolymer resin used in the present invention is obtained by a copolymerization reaction of vinyltoluene and butadiene. The ratio of toluene and butadiene used is preferably in the range of 0.1 to 1 mole of butadiene per mole of vinyltoluene, and the molecular weight of the resulting vinyltoluene/butadiene copolymer resin is preferably in the range of 1,000 to 200,000.

When monomers other than butadiene are used as copolymerizable monomers, such as isobutylene, diisobutylene, styrene, etc., the wear resistance effect is improved, but the resolution is not very good and sometimes This is undesirable because it gives an uneven transferred image.

Furthermore, as is clear from the comparative examples described below, vinyl toluene homocopolymers have high crystallinity and are brittle, resulting in poor body abrasion resistance, so that the intended purpose of the present invention cannot be achieved.

The vinyltoluene/butadiene copolymer resin used in the present invention has a melting point or softening point of 60°C to 150°C.
Preferably, the range is . Melting point or softening point is 60℃
If it is lower, image fading occurs when the transferred image is rubbed by hand, resulting in poor abrasion resistance. On the other hand, if the temperature exceeds 150°C, there is a drawback that transferability deteriorates.

The coloring agent used in the present invention is selected from disperse dyes such as azo dyes and anthraquinone dyes, and coloring pigments such as organic or inorganic pigments and carbon black, taking hue, density, etc. into consideration.
Furthermore, the vinyltoluene/butadiene copolymer resin used in the present invention is used in an amount of 0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight, per 1 part by weight of the above-mentioned disperse dye or coloring pigment. .

In the present invention, either a solution method or a melt method can be adopted as a method for layering a transfer layer made of a vinyltoluene/butadiene copolymer resin, a colorant, etc. on a sheet base material. In order to obtain even better transferability or resolution, it is desirable to make the transfer layer as thin as possible, particularly preferably in the range of 1 to 10μ. Below 1μ,
There is a disadvantage that recording density cannot be obtained, and if the thickness exceeds 10μ, heat conduction is insufficient, complete transfer is not performed, and a uniformly transferred image cannot be obtained.

In the present invention, if necessary, the melting point is 60 to 120.
Thermoplastic substances in the temperature range of °C, for example, animal waxes such as beeswax and Serraz wax, vegetable waxes such as carnauba wax, mineral waxes such as Montan wax, petroleum waxes such as paraffin wax, microcrystalline wax, etc. Synthetic waxes such as polyalcohol esters of higher fatty acids, higher amides, higher amines, condensates of fatty acids and amines, condensates of aromatics and amines, synthetic paraffins, chlorinated paraffins, etc. can be used in combination.

To obtain a record using the thermal transfer type recording material of the present invention, the surface of the transfer layer is applied to ordinary paper, plastic film, metal foil, etc., and the recording material is heated from the back side with a thermal head such as a thermal recording head. All you have to do is apply pressure. The recording surface obtained in this way is
It has wear resistance even as it is, and even if the recording surface is intentionally scraped, there is little risk of tampering because the colorant has penetrated into the inside. It is also possible to further improve wear resistance and permeability by applying heat to this surface using a heater or flash lamp.

In the present invention, the support for forming the transfer layer is preferably a plastic film (for example, polyester, polycarbonate, cellulose acetate, etc.) having a thickness of 5 to 30 microns, cellophane, condenser paper, glassine paper, etc.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Vinyltoluene/butadiene copolymer resin (Bryolite VT manufactured by Gutdeyer) 40 parts by weight Carbon black 45 parts by weight Montan wax (OP-WAX manufactured by Hoechst)
10 parts by weight Stearylamine 5 parts by weight The above composition was melted by heating and applied as a uniform dispersion onto condenser paper (12μ thick) to a thickness of 5μ to form a transfer sheet (thermal transfer recording material). Obtained. The transfer layer surface of this transfer sheet was placed on plain paper (55 g/m ² ) and printed using a facsimile machine (RIFAX-3300, manufactured by Ricoh Co., Ltd.) to obtain a black record. This transferred image had good abrasion resistance, and there was no image bleeding. Also, even if you rub it with a sand-filled eraser, it will penetrate into the paper, so there is little risk of tampering.

Comparative Examples 1 and 2 Transfer sheets of Comparative Examples 1 and 2 were obtained by removing the vinyltoluene/butadiene copolymer resin from Examples 1 and 2, and recorded images were obtained in the same manner as in Example 1. This transferred image will peel off just by rubbing it with your hands.
The abrasion resistance was such that it could not be put to practical use.

Comparative Example 3 A comparative transfer sheet was obtained in exactly the same manner as in Example 1 except that polystyrene resin was used instead of the vinyltoluene/butadiene copolymer. A transferred image was obtained using this product in the same manner as in Example 1. This transferred image had poor resolution and was uneven.

Comparative Example 4 A comparative transfer sheet was obtained in the same manner as in Example 1 except that a vinyltoluene homopolymer was used instead of the vinyltoluene/butadiene copolymer in Example 1. A transferred image was obtained using this transfer sheet in the same manner as in Example 1. This transferred image had poor resolution and was uneven.

Claims (1)

[Claims] 1. In a heat-sensitive recording material used in a heat-sensitive transfer recording method in which recording is obtained by transferring the transfer layer of a transfer sheet to a recording material using a thermal head, the transfer layer has a melting point or softening point of 60°C to 150°C. 1. A heat-sensitive transfer recording material, characterized in that it contains a vinyltoluene/butadiene copolymer resin and a colorant.