JP2671474B2 - 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 consisting of a heat-melting ink layer such as wax that has been generally used in the past is used to thermally transfer onto the above-mentioned substrate, the transferred image is not fixed, and if the image portion is rubbed with a hand, the tail is pulled. 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 57-785. What is described in this patent is one in which thermal transfer recording is carried out on a substrate having a smoothness, for example, a transfer target having a porous ink absorbing layer provided on a plastic sheet. However, although the image portion cannot be removed even by rubbing hard with a hand, the phenomenon of tailing has not been solved, and the fixing property 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.

<Means for Solving the Problems> That is, the present invention comprises a thermal transfer recording layer containing a colorant composed of a pigment, an epoxy resin, and a lubricant as main components on a substrate having heat resistance. The resin has an epoxy equivalent (the number of grams of the resin containing 1 gram of epoxy group) of 400 to 5000, a melting point (Durance mercury method) of 60 ° C to 150 ° C, and a molecular weight of 800 to 6000. At least one of Teflon powder, polyethylene powder, and a metal salt of a higher fatty acid such as zinc stearate is used, which is a resin-type thermal transfer recording material.

<Operation> The principle of transfer of the resin-type thermal transfer recording material of the present invention is that heat is applied to the thermal transfer recording material by a thermal medium such as a thermal head, and the heat melts the epoxy resin, which is a heat-meltable substance, in the thermal transfer recording layer. In this state, the adhesiveness is developed and the image is recorded by thermally adhering to the transferred material. Therefore, the transferred recorded image has excellent mechanical strength.

Hereinafter, the resin type thermal transfer recording material of the present invention will be described in detail.

The recording material of the present invention comprises a substrate and a thermal transfer recording layer formed thereon, and the substrate may be any one having heat resistance, high dimensional stability and high surface smoothness. Preferably, a polyester film having a thickness of 2 to 10 μm is provided with a layer for preventing sticking of the thermal head on the back surface.

The thermal transfer recording layer is composed of a colorant composed of a pigment, a lubricant and an epoxy resin as a heat-melting substance.

The epoxy resin used in the present invention has a melting point of 60 ° C. to 150 ° C. in consideration of suitability for a heat medium such as a thermal head and durability of an image after transfer recording. Furthermore, as another characteristic of the epoxy resin, the epoxy equivalent is
It must be between 400 and 5000 and have a molecular weight in the range of 800 and 6000.

The thermal condition for thermal transfer using a thermal head is usually 300 to 400 ° C. for a few milliseconds, and when this is converted into a static condition, it is 100 to 150 ° C. for 5 seconds. Further, as described above, in order to perform thermal transfer recording, it is necessary to heat the epoxy resin until it melts.

Therefore, considering the amount of heat supplied from the thermal head and the melting state of the epoxy resin, the upper limit of the melting point is 150
° C. If a resin having an amount higher than this upper limit is used, more energy is required for transfer, and the life of the thermal head becomes extremely short. In addition, the lower limit of 60 ° C is set in consideration of the retention stability of the image after transfer recording, and when an epoxy resin with a melting point of 60 ° C or less is used, tailing may occur when rubbed by hand. The phenomenon occurs.

For the above reasons, the melting point is 60-150 ℃ and the epoxy equivalent is 400.
~ 5000, and an epoxy resin having a molecular weight in the range of 800 to 6000 is selected. Examples of such an epoxy resin include bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, resorcinol diglycidyl ether, and cresol novolac. Glycidyl ether type epoxy resins such as polyglycidyl ether, tetrabromobisphenol A diglycidyl ether and bisphenol hexafluoroacetone glycidyl ether, glycidyl ester type epoxy resins such as phthalic acid diglycidyl ester and dimer acid diglycidyl ester, and triglycidyl isocyanate Glycidyl amine type epoxy resins such as nurate, tetraglycidyl diaminodiphenylmethane, tetraglycidyl metaximendiamine, and hexahydrate May be mentioned bisphenol A diglycidyl ether, polypropylene glycol diglycidyl ether, aliphatic epoxy resins such as neopentyl glycol diglycidyl ether.

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 the lubricant that can be used include Teflon powder, polyethylene powder, and higher aliphatic metal salts such as zinc stearate.

As the colorant, dyes and pigments which 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, specifically, titanium oxide, 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, 40 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.

The method for producing a thermal transfer recording material of the present invention is a composition in which a colorant, an epoxy resin and a lubricant are dispersed or dissolved in a solvent on a substrate such as coated paper or plastic, bar coat, blade coat, air knife coat, It is formed by applying a solvent coating method such as gravure coating or roll coating and drying to form a thermal transfer recording layer.

<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.

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.

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

4.5μ with a sticking prevention layer on the back side
On a polyester film with a thickness of m, pulverize and disperse in a sand mill for 1 hour and 30 minutes, and apply a coating liquid having the following composition with a bar coater to a dry weight of 2.0 g / m ² , and dry. Then, a thermal transfer recording layer was formed to produce a resin type thermal transfer recording material.

Composition of coating composition for thermal transfer recording layer <Evaluation of Examples> The obtained thermal transfer recording material was used as a thermal simulator manufactured by Toshiba Corp. (printing conditions, applied power 0.35w / dot, pulse width 2.5).
When a 250 μm-thick polyvinyl chloride sheet was heat-transferred onto a coated paper by ms on / off), a clear transfer image was formed. 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 durability of the image after recording can be obtained, and the object of the present invention is achieved.

<Effect> The present invention can provide a thermal transfer recording material capable of printing a clear recording image on a substrate such as coated paper or plastic sheet by using a heat medium such as a thermal head. In addition, the present invention provides a thermal transfer recording material which is excellent in storage stability of images after transfer, particularly in solvent resistance and mechanical strength.

Claims (2)

(57) [Claims] 1. A thermal transfer recording layer containing a colorant comprising a pigment, an epoxy resin, and a lubricant as main components on a heat-resistant substrate, wherein the epoxy resin has an epoxy equivalent (1 gram). As grams of resin containing epoxy groups)
400 to 5000, a melting point (Durance mercury method) of 60 to 150 ° C, and a molecular weight of 800 to 6000,
Moreover, at least one of Teflon powder, polyethylene powder, and a metal salt of a higher fatty acid such as zinc stearate is used as the lubricant, which is a resin-type thermal transfer recording material. 2. A composition for forming a thermal transfer recording layer comprises 10 to 30 parts by weight of a colorant, 40 to 80 parts by weight of an epoxy resin, and 5 to 30 parts by weight of a lubricant, based on 100 parts by weight of the total solid content. The resin-type thermal transfer recording material according to claim 1, which has a composition of parts.