JP2581228B2 - Resin-type thermal transfer recording material - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording material capable of forming a clear recorded image on a smooth paper such as a coated paper or a plastic sheet. In particular, the present invention relates to a thermal transfer recording material having a transferred image excellent in chemical resistance and excellent in mechanical strength.

<Prior art> The thermal transfer recording method is a simple mechanism, a dry type, and
Because it has advantages such as maintenance-free, it is widely used in various printers and facsimile fields. Recently, the use of printing visible information on substrates other than plain paper, for example, on coated paper or plastic sheets has been increasing. However, when a thermal transfer material composed of a hot-melt ink layer such as wax, which is generally used in the past, is thermally transferred onto the above substrate, the transferred image is not fixed. Contamination occurs. Also,
If you rub strongly, the image part will be removed. A method for solving such a phenomenon is disclosed in JP-A-57-784 and JP-A-57-785. What is described in this patent is one in which thermal transfer recording is performed on a substrate having a smooth ink, such as a plastic sheet, provided with a porous ink-adsorbing layer. However, the phenomenon that the image portion is not removed even if the hand is rubbed strongly with the hand is not solved, and the fixability of the image is not perfect.

<Problems to be Solved by the Invention> The present invention is to solve the above-mentioned drawbacks of the prior art, and (1) coated paper or a substrate such as a plastic sheet,
Provided is a thermal transfer recording material that can be printed as a clear recorded image using a thermal medium such as a thermal head.

(2) To provide a thermal transfer recording material having excellent preservability of an image after transfer, particularly excellent in solvent resistance and mechanical strength.

(3) The image portion does not leave a tail even when strongly rubbed with the hand.

<Means for Solving the Problems> That is, according to the present invention, a heat-resistant base material having a melting point
A release layer composed of a heat-meltable compound containing waxes as a main component at 60 to 120 ° C and a colorant and a glass transition temperature of 50 to 70 ° C, a liquefaction temperature of 70 to 100 ° C, and a molecular weight of 2000 to 800
A resin-type transfer material comprising a thermal transfer recording layer containing a saturated polyester resin and a lubricant as main components.

<Detailed Description and Function of the Invention> Hereinafter, the resin-type thermal transfer recording material of the present invention will be described in detail.

The recording material of the present invention is composed of a support and a release layer formed thereon, and a thermal transfer recording layer.The support has heat resistance, high dimensional stability and high surface smoothness. Any material can be used, but preferably a polyester film having a thickness of 2 to 10 μm and a layer for preventing sticking of the thermal head provided on the back surface is used.

The release layer is formed so that the thermal transfer recording layer can be easily separated from the support during thermal transfer recording, and as a result, a recorded image having excellent resolution can be obtained.

In other words, the principle of thermal transfer recording is that heat is applied to the thermal transfer recording material by a thermal medium such as a thermal head, and the heat causes the saturated polyester resin in the thermal transfer recording layer to be in a molten state, whereby adhesiveness is developed and heat is applied to the transferred body. If the release layer is not formed at this time, the saturated polyester resin that has developed tackiness will adhere to the transfer target and increase the adhesive force with the support. However, the separation from the support becomes poor, and the resolution of the transferred image deteriorates.

As the heat-fusible substance used for the release layer, waxes having low adhesion to the support and low cohesion are used. Specific examples thereof include waxes having a melting point of 60 to 120 ° C. such as paraffin wax, carnauba wax, montan wax, microcrystalline wax, higher fatty acids, higher alcohols, higher fatty acid esters, and higher fatty acid amides. In addition, a low softening point having a certain degree of adhesion between the support and the support as necessary in the release layer,
Low molecular weight resin components, for example, epoxy resin, styrene oligomer, ethylene-vinyl acetate copolymer, polyamide resin,
A binder such as a polyurethane resin may be added. The amount added at that time is 20 parts by weight based on 100 parts by weight of the total solid content of the release layer.
It is preferable that the amount is not more than part by weight.

The thermal transfer recording layer has a colorant and a glass transition temperature of 50 to 70 ° C.,
It is composed of a saturated polyester resin having a liquefaction temperature of 70 to 100 ° C. and a molecular weight of 2,000 to 8,000, and a lubricant.

The saturated polyester resin has a molecular weight of 2,000 to 8000, a liquefaction temperature of 70 to 100 ° C, and a glass transition temperature of 50 to 70 ° C in consideration of the suitability for the thermal head (thermal transfer characteristics) and the durability of the transferred image after transfer recording. Use things.

Generally, a saturated polyester resin having a high degree of polymerization has a softening point of 130 ° C. or higher when the glass transition temperature is 50 ° C. or higher, which is not preferable in terms of thermal transfer characteristics. When the molecular weight is reduced, the softening point, that is, the liquefaction temperature can be lowered without much change in the glass transition temperature. The reason for setting the molecular weight to 2000 to 8000 is that the liquefaction temperature is reduced to 70 to
This is to lower the temperature to 100 ° C. and improve the thermal transfer characteristics.

Further, the lower limit of the glass transition temperature was set to 50 ° C., because the stability of the image thermally transferred and recorded on the transfer material, which is the object of the present invention, was emphasized. The stability of the thermal transfer image means that, in a normally used environment, tailing does not occur due to hand rubbing. 50 ° C. was set as the lower limit of the glass transition temperature at which no tailing occurs.

For the above reasons, the molecular weight is 2000-8000 and the liquefaction temperature is 70-100.
A saturated polyester resin having a glass transition temperature of 50 to 70 ° C. is selected. Such a saturated polyester resin is formed by polycondensation of a dicarboxylic acid component and a diol component. For example, as the dicarboxylic acid component, terephthalic acid, aromatic dicarboxylic acid such as isophthalic acid, adipic acid, aliphatic dicarboxylic acid such as sebacic acid, and the diol component, ethylene glycol, 1.4-butanediol, diethylene glycol, neopentyl It is obtained by subjecting various combinations of glycols and the like to polycondensation. Therefore, depending on the mixing ratio, a saturated polyester resin of a terminal hydroxyl group type or a saturated polyester resin of a terminal carboxyl group type can be obtained.

Lubricant is a component necessary for improving the transferability at the time of thermal transfer and the abrasion resistance of an image recorded by thermal transfer.The addition of the lubricant eliminates damage to the image due to scratches such as scratches and reduces wear due to an eraser or the like. Become stronger.

Specific examples of lubricants that can be used include Teflon powder, polyethylene powder, animal wax, plant wax, mineral wax, natural wax such as petroleum wax, synthetic hydrocarbon wax, aliphatic alcohol and acid wax, fatty acid Synthetic waxes such as ester and glycerite waxes, hydrogenated waxes, synthetic ketone waxes, amine and amide waxes, chlorinated hydrocarbon waxes, synthetic animal wax waxes, alpha-olefin waxes, and zinc stearate Metal salts of higher fatty acids and the like can be mentioned.

As the colorant, dyes and pigments that are usually used can be used, but in consideration of the weather resistance of the transferred and recorded image, it is preferable to use an inorganic or organic pigment, and specifically, an acid value titanium. , Calcium carbonate, Hansa Yellow, Oil Yellow 2G, carbon black, oil black,
Pyrazolone orange, oil red, red iron oxide, anthraquinone violet, phthalocyanine blue, phthalocyanine green, aluminum powder, bronze powder, pearl essence, magnetic powder and the like are used.

The composition of the composition for forming the thermal transfer recording layer is 10 to 30 parts by weight of a colorant, 50 to 80 parts by weight of a thermoplastic resin, and 5 to 30 parts by weight of a lubricant based on 100 parts by weight of the total solid content. Parts by weight, to which various additives can be added as required. The amount of addition is preferably 10 parts by weight or less based on 100 parts by weight of the composition for forming the thermal transfer recording layer.

In the method for producing a thermal transfer recording material of the present invention, first, a release layer composition is applied to the surface of a support by a hot melt method or a solvent coating method, and dried to form a release layer, and coloring is performed thereon. A composition obtained by dispersing or dissolving an agent, a saturated polyester resin and a lubricant in a solvent, a bar code,
Blade coat, air knife coat, gravure coat,
Apply by solvent coat method such as roll coat,
It is formed by drying to form a thermal transfer recording layer.

<Example> Hereinafter, an example of the present invention will be described. “Parts” in each embodiment means parts by weight.

<Example 1> Composition of coating liquid for thermal transfer recording layer 6 μm with an anti-sticking layer provided on the back surface in advance
A release layer made of carnauba wax was formed on a polyester film having a thickness of 2 by a hot melt coating (flexographic printing) method so that the coating amount was 0.8 g / m ² .
On the layer, a composition obtained by pulverizing and dispersing a coating liquid having the above-mentioned composition with a sand mill for 1 hour was dried at 2.0 g / m ^2.
Was applied by a bar coater and dried to form a thermal transfer recording layer to produce a resin-type transfer recording material.

<Example 2> Formulation composition of coating liquid for release layer Composition of coating composition for thermal transfer recording layer A dry weight of 1.0 g / m was obtained by pulverizing and dispersing the coating liquid for a release layer having the above composition for 1 hour with a paint conditioner.
At ^2, thickness 4μ subjected to pre backside heat treatment
m on a polyester film with a wire bar,
After drying, a release layer was formed. The thermal transfer recording layer coating solution obtained by uniformly dispersing in advance by means of a sand mill over the layer, dry weight coating with a wire bar so as to 2.5 g / m ^2, and dried to form a thermal transfer recording layer Thus, a resin-type thermal transfer recording material was obtained.

<Example 3> Composition of coating liquid for release layer Composition of coating composition for thermal transfer recording layer A dry weight of 0.5 g / m was obtained by pulverizing and dispersing a coating liquid for a release layer having the above composition for one year with a paint conditioner.
6μ thick, heat-treated on the back in advance to ²
m was applied and dried on a polyester film using a wire bar to form a release layer. The thermal transfer recording layer coating solution formed by uniformly dispersing in advance sand on the layer, dry weight is applied and dried with a wire bar so as to 2.5 g / m ^2, forming a thermal transfer recording layer Thus, a resin type thermal transfer recording material was produced.

<Evaluation of Examples 1 to 3> The obtained thermal transfer recording material was subjected to thermal simulator [printing conditions, (thin film head: resistance 380Ω, dot diameter 6 dot / m).
m) With an applied power of 0.2 w / dot and a pulse width of 2.5 ms ON / OFF], thermal transfer was performed on a 250 μm-thick vinyl chloride sheet and art paper, and clear transfer images were formed in all of Examples 1 to 3. Further, the durability of the transferred and recorded image was evaluated. Table 1 shows the results.

As is clear from Table 1, an excellent thermal transfer recorded image having the durability (plasticizer resistance, abrasion resistance, scratch resistance and chemical resistance) of the image after recording can be obtained. The goal has been achieved.

<Effect of the Invention> The thermal transfer recording material of the present invention can form a clear thermal transfer recorded image on a substrate such as a coated paper or a plastic sheet by a thermal medium such as a thermal head. The fixability of the image is good, and the image does not leave a tail even if it is rubbed strongly by hand.

In addition, it has basic characteristics such as color display and monochrome display and can form an image with high durability, so it can display not only POS-related labels and the like, but also cards and sealless It can be used in an extremely wide range of fields, such as recording of variable information such as commuter passes and tickets, and a balance display medium for prepaid cards.

Claims (2)

(57) [Claims] 1. A support having a heat-resistant layer and having a melting point of 60 to 12
A release layer made of a heat-fusible compound containing waxes as a main component at 0 ° C. and a colorant and a glass transition temperature of 50 ° C. on the release layer.
A resin-type thermal transfer recording material comprising: a saturated polyester resin having a liquefaction temperature of 70 to 100 ° C. and a molecular weight of 2000 to 8000; and a thermal transfer recording layer mainly composed of a lubricant. 2. A composition for forming a thermal transfer recording layer, wherein the colorant is 10 to 30 parts by weight based on 100 parts by weight of the total solid content.
2. The composition according to claim 1, wherein the saturated polyester resin is 50 to 80 parts by weight and the lubricant is 5 to 30 parts by weight.
2. The resin-type thermal transfer recording material according to item 1.