JPH0255191A - Heat sensitive transfer material - Google Patents

Abstract

PURPOSE:To enable recording many times in high printing quality by providing a nontransfer adhesive layer and a heat transfer specific physical property ink layer from a support side on the support. CONSTITUTION:A heat sensitive transfer material 1 has a nontransfer adhesive layer 3 and an ink layer 4 to be printable many times on a support 2. The layer 4 is mixed with heat fusible resin of adhesive strength imparting agent, substantially nonheat fusible cohesive force control agent, colorant, as required thermoplastic resin, wax surfactant, plasticizer, filler, etc. so that the cohesive force of the ink layer is so regulated as to be ranged from 5-60g/cm. The adhesive strength imparting agent is made of at least one of low molecular weight polyester resin, acrylic resin, low molecular weight PVA resin, resin ester resin, terpene resin, petroleum resin, alkylphenol resin, and coumarone-indene resin. The cohesive force control agent must has 85 deg.C or higher of melting point, and includes, for example, fatty acid amid, polyethylene having 1000-7000 of mean molecular weight.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal transfer material, and particularly to a thermal transfer material that has excellent transferability and can be printed many times.

[Conventional technology]

The thermal transfer recording method has the general characteristics of the thermal transfer recording method such that the equipment used is lightweight, compact, noiseless, and has excellent operability and maintainability. Paper is characterized by its excellent durability and has recently been widely used. This heat-sensitive transfer recording method uses a heat-sensitive transfer material in which a heat-transferable ink layer formed by dispersing a coloring material in a heat-melting binder is coated on a support, which is generally in the form of a sheet. is superimposed on the recording medium so that its thermally transferable ink layer is in contact with the recording medium, and heat is supplied from the support side by a thermal head to transfer the melted ink layer onto the recording medium, thereby creating a heat-supplied shape ( This is to obtain a transferred recorded image according to the pattern).

However, in the conventional thermal transfer recording method, the thermal transfer material can be used only once, so the running cost is high compared to other printing methods. In order to overcome this drawback, many proposals have been made for heat-sensitive transfer materials that can be used many times, and their content can be broadly divided into two categories.

The first method is to create a matrix using an organic polymer material or inorganic fine powder, impregnate the low melt viscosity ink into the matrix, and apply heat without transferring the matrix material. The second method for obtaining prints is a method in which the melt viscosity and cohesive force of the ink layer are controlled and the ink is peeled off many times.

Regarding the first method, if the matrix is properly obtained, a fairly good print can be obtained, but the solid material that does not originally participate in transfer must account for some percentage of the ink, and the ink should be kept as unchanged as possible. This is a disadvantageous method for obtaining multiple prints. - Method No. 2 is more advantageous than the first method because all of the ink layer is used for printing, but requires delicate control of the adhesive force to paper and the cohesive force within the ink layer.

[Problem to be solved by the invention]

An object of the present invention is to eliminate the drawbacks of the conventional multiple-time recording method and obtain multiple-time recording with high print quality.

[Means to solve the problem]

The present invention has a non-transferable adhesive layer and a thermally transferable ink layer on a support from the support side, and the ink layer has a cohesive force of 5.
g/cm to 60 g/cI11, and the ink layer further contains a low molecular weight polyester resin, an acrylic resin, a low molecular weight PVA resin, a rosin ester resin, a terpene resin, or a petroleum resin as an adhesive force imparting agent. The present invention is a thermal transfer material characterized by containing at least one type of resin, alkylphenol resin, and coumaron-indene resin.

In the thermal transfer material of the present invention, a non-transferable adhesive layer is provided from the support side, and this layer serves to prevent the ink layer from being transferred to the recording medium all at once. Next, the ink layer provided on the adhesive layer contains an adhesive force imparting agent that is basically heat-meltable and has strong adhesive force to the recording medium, and a cohesive force control agent that does not substantially melt with the energy applied during thermal transfer. Consists of agent and coloring agent.

Since the cohesive force control agent does not substantially melt, the cohesive force when the thermal transfer material is manufactured by coating and drying is kept the same as the cohesive force when heated printing is performed, cooled, and peeled off. I can do it. For example, if the cohesive force control agent melts when heated and printed, especially if it is highly crystalline, the cohesive force may differ from the originally designed cohesive force after being subjected to thermal history, which is not preferable.

As explained above, the adhesive force to the paper and the cohesive force of the ink layer are delicately matched, and since the cohesive force control agent does not substantially melt, the ink layer does not dig deep into the paper when heat is applied, achieving multiple printings. The present invention was completed based on this discovery.

The present invention will be explained in more detail below. In the following description, "%" and parts indicating quantitative ratios are Ii unless otherwise specified.
Based on quantity.

FIG. 1 is a schematic cross-sectional view in the thickness direction showing one example of the thermal transfer material of the present invention. The thermal transfer material 1 shown in FIG. 1 usually has a non-transferable adhesive layer 3 and an ink layer 4 that can be printed multiple times on a sheet-like support 2.

As the support 2, conventionally known films and papers can be used as they are, such as films of relatively heat-resistant plastics such as polyester, polycarbonate, triacetylcellulose, polyphenylene sulfide, polyimide, cellophane, or parchment paper. , condenser paper, etc. can be suitably used. The thickness of the support should be 1 when considering a thermal head as a heat source during thermal transfer.
It is preferable that it is about 15 microns. In addition, when using a thermal head, a heat-resistant protective layer made of silicone resin, fluororesin, polyimide resin, epoxy resin, phenol resin, melamine resin, acrylic resin, nitrocellulose, etc. is applied to the surface of the support that comes into contact with the thermal head. The heat resistance of the support can be improved by providing
Alternatively, support materials that could not be used conventionally can also be used.

As the non-transferable adhesive layer 3, any resin may be used as long as it has a high softening point, hardly melts when ignited by heat, and has high adhesion to the support and ink, such as polyester resin, polyvinyl butyral, etc. Resin, polyurethane resin, vinyl acetate resin, etc. are used.

As for the thickness, the thinner the better in order to maintain the adhesive strength between the support and the ink layer without reducing the thermal sensitivity, preferably 0.
．． It is 3μ to 3μ.

Next, the heat-transferable ink layer 4 is made of a heat-melting resin which is an adhesive force imparting agent, and a material that is substantially non-thermal meltable (substantially non-thermal meltable means that it does not melt when heat is applied in a thermal head). ) cohesive force control agent, colorant, thermoplastic resin, wax surfactant, plasticizer, filler, etc. are mixed as necessary to reduce the cohesive force of the ink layer to 5 g.
It is formed by adjusting the /cI to fall within the range of 11 to 60 g/cm.

The adhesive strength agent is at least one of a low female weight polyester resin, an acrylic resin, a low molecular weight PVA resin, a rosin ester resin, a terpene resin, a petroleum resin, an alkylphenol resin, and a coumaron-indene resin. Become.

As a polyester resin, the number average molecular weight is 1.000
~15,000 is preferably used. The acrylic resin has a number average molecular weight [5,000 to 100,000
Preferably. As the PVA resin, one having a number average molecular weight of 500 to 6,000 is suitable. Rosin ester resins include rosin glycerin ester, hydrogenated rosin glycerin ester, hydrogenated rosin pentaerythritol ester, rosin pentaerythritol ester, hydrogenated rosin diethylene glycol ester, hydrogenated rosin methyl ester, disproportionated rosin, maleated rosin, etc. There is. As terpene resins, α-pinene polymer, β
-Pinene polymers, natural terpene resins, etc. Petroleum-based resins include alicyclic saturated hydrocarbon resins, aliphatic saturated hydrocarbon resins, and aromatic hydrocarbon resins. In addition, alkylphenol resins and coumaron/indene resins are preferably used. Rosin ester resin The resin described below has a number average molecular weight in the range of 300 to 3,000.

The cohesive force control agent must have a melting point of 85°C or higher. An example of this is shown below.

Fatty acid amides such as myristylamide, palmitylamide, stearylamide, N-hydroxyethyl 1
2-Hydroxystearylamide, N,N'-ethylenebisoleylamide, N.

N'-ethylenebislycylylamide, N,N'-ethylenebis12-hydroxystearylamide, N,N'
-Ethylenebisstearylamide, N,N'-hexamethylenebislycylylamide, N,N'-hexamethylenebis12-hydroxystearylamide, N,N'-
Examples include xylylene bis-12-hydroxystearylamide.

Metallic soaps include aluminum stearate, calcium stearate, calcium laurate, syncstearate, synclaurate, and magnesium stearate. Unexamined Japanese Patent Publication No. 1973 as acrylic silica modified resin
There is one described in 9-71316. Examples of low molecular weight ethylene resins include polyethylene, polyethylene oxide, ethylene/acrylic acid, and ethylene/vinyl acetate having a number average molecular weight of 1,000 to 7,000. Waxes include Sasol wax and Montan wax.

As the colorant, dyes and pigments used in ordinary printing inks and inks for writing instruments can be used, and the content in the ink layer is preferably 3% to 60%, and if it is 3% or less, the print density will be low. If it is lower than 60%, the transferability will be poor.

The concentration of the adhesive force imparting agent is about 20% to 70%, more preferably 30% to 60%; if it is less than 20%, transfer will not occur and if it exceeds 70%, the cohesive force will be too high and it will not be possible to print multiple times. It tends to disappear.

Furthermore, if the cohesive force control agent content is less than 20%, the cohesive force becomes too high, resulting in multiple printing, and if it exceeds 70%, transfer tends to fail.

The adhesive force imparting agent is made of a resin that is softened when heat is applied, has a low melt viscosity, and exhibits strong adhesive force to the recording medium. However, since the melt viscosity of wax does not decrease, combined with the effect of the cohesion control agent, it prevents the recording medium from penetrating the ink layer.

On the other hand, the cohesive force control agent probably exists in the form of fine particles in the ink layer and has a high melting point, so it does not substantially melt, and because it remains in the form of fine particles, the cohesive force does not increase even when it peels off after heated printing, and it remains intact. It is thought that there is no possibility of actual transcription.

Next, a method for manufacturing the thermal transfer material of the present invention will be explained.

A resin with good adhesion to the support 2 is dissolved in a solvent or made into an aqueous dispersion on the support 2, which has been coated with a heat-resistant back treatment coating if necessary, using a mailer coater or a gravure coater. The adhesive layer 3 is provided by coating and drying.

Next, a coating liquid is prepared by dissolving or dispersing the coloring agent, adhesive strength agent, cohesive force control agent, and other hot-melt binders, fillers, etc. in a solvent.
A coating solution is created by dissolving or dispersing the direct distribution material in water, and the coating solution is coated with a mailer coater or gravure coater and then dried to create a thermal transfer medium.

〔Example〕

Example 1 A vinyl acetate/ethylene emulsion was coated as an adhesive layer on a heat-resistant 6μ polyethylene terephthalate film at a solid content of 1 g/m 2 and dried. Next, apply the following ink A on the adhesive layer with a solid content of 10 g.
/m2 and then dried to complete a heat-sensitive transfer material. Next, a slit was made to a width of 8111 m, and printing was repeated using a Canon ■ electronic typewriter 5P400X so that the printed areas almost overlapped. The evaluation results are shown in Table 3.

Ethylene bisstearylamide water dispersion 38 parts by weight (solid content) Carnauba wax water dispersion ink A 2 parts by weight (solid content) Water-soluble low molecular weight polyester resin 35 parts by weight (solid content) Carbon black water dispersion 25 parts by weight (Solid content) Cohesive force was measured by the method described below.

The heat-sensitive transfer material of the present invention is prepared by sequentially laminating an adhesive layer and an ink layer on the polyester film of 6-. Next, an adhesive tape is pasted onto the ink layer of the thermal transfer material, and then the adhesive tape is peeled off to separate the ink layer, which has the weakest cohesive force, and the cohesive force at this time is measured under the following measurement conditions.

In addition, if the above-mentioned material is used as the material constituting the adhesive layer, the adhesive force between the polyester film and the adhesive layer, the cohesive force of the adhesive layer, and the adhesive force between the adhesive layer and the ink layer are 60 g.
/ cm or more, therefore, according to this measurement method, the cohesive force of the weakest ink layer can be measured.

Measurement conditions Equipment used Tensile strength tester Tensilon RTM-100 Sample 7. 5mm width Measuring angle: 90° Measuring speed: 200mm/min Measuring strength: 25°C The cohesive force is expressed as the value obtained by dividing the above measured value of peel strength by the length of time during which the sample was measured (in this case, 0.75 cm).

Examples 2 to 4 In Examples 2 to 4, solid content expressed as P/l type and weight 5 U, heat-sensitive transfer was carried out in the same manner as in Example 1, except that ink A of Example 1 was changed according to Table 1. A material was created and evaluated.

(Comparative Example) Next, a comparative example will be shown. Samples for the comparative example were prepared in the same manner as in Examples 2 to 4 according to Table 2, and evaluated in the same manner. The above results are shown in Table 3.

table ◎Very good.

○ The concentration is a little thin, but it is durable enough for use.

〔Effect of the invention〕

As explained in detail above, by delicately controlling the adhesive force to the paper and the cohesive force of the ink layer, it is possible to prevent the paper fibers from penetrating the ink layer when the ink layer is heated by the thermal head. By controlling the physical properties of the ink, it is possible to obtain prints that are sufficiently durable even after repeated use about seven times, and the biggest disadvantage of the thermal transfer recording method, which is the high running cost compared to other recording techniques, has been overcome.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing an example of the thermal transfer material of the present invention. 1...Thermal transfer material, 2-----1 support, 3.
...adhesive layer, 4...thermally transferable ink layer. Patent applicant Canon Co., Ltd.

Claims (1)

[Claims] 1) A non-transferable adhesive layer and a thermally transferable ink layer are provided on the support from the support side, and the cohesive force of the ink layer is 5 g/c.
A heat-sensitive transfer material characterized in that it is in the range of m to 60 g/cm. 2) The ink layer contains a low molecular weight polyester resin, an acrylic resin, a low molecular weight PVA resin as an adhesive force imparting agent,
Rosin ester resin, terpene resin, petroleum resin,
The thermal transfer material according to claim 1, containing at least one of an alkylphenol resin and a coumaron-indene resin. 3) The thermal transfer material according to claim 2, wherein the ink layer contains a cohesion control agent that does not melt during thermal transfer.