JPH0548758B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sublimation type heat-sensitive image-receiving paper, and particularly to an image-receiving paper suitable for use in making hard copies of information.

[Conventional technology]

A dye-sublimation heat-sensitive transfer printer has been proposed for the reproduction of multicolor gradations on televisions, facsimile machines, etc., and its future prospects are high due to its various features.

The above-mentioned sublimation type thermal transfer method converts an image signal from a TV, facsimile, etc. into a heat signal, and heats a sheet having a color material layer (hereinafter referred to as a color sheet), thereby converting the energy into the heat signal. The coloring material is sublimated, transferred to the image-receiving paper, and diffused to form the image as a whole.Currently, the image-receiving paper has a high smoothness and a high affinity with the sublimable coloring material. Those with a layer mainly made of polymers such as saturated copolyester polyester or acetate are used.

However, this sublimation type heat-sensitive method requires a large amount of energy to sublimate, transfer, and diffuse the coloring material, and the transfer speed is slow.In order to increase the speed, it is necessary to speed up the transfer and diffusion of the coloring material on the image-receiving paper. If an amorphous polymer is used for this purpose, the heat resistance of the surface layer of the image-receiving paper will inevitably be low, resulting in fusion between the image-receiving paper and the color sheet during printing, and other speed-improving measures will be needed. In order to raise the printing temperature, the image-receiving paper also needs to have special heat resistance, which inevitably increases the overall cost.

As one of the countermeasures against this problem, as disclosed in JP-A No. 58-212994, radical polymerizable thermoplastic resins such as saturated copolyester and acetate, which are dyeable to disperse dyes, are used. A method has been proposed in which a composition is mixed, applied to the surface of a substrate, and then cured.

[Problem that the invention seeks to solve]

However, the above method has the following drawbacks.

(1) Since commonly used saturated copolymerized polyester, acetate, etc. are used, the transfer energy is not very low. In other words, high transfer energy is required.

(2) Mixing and coating a thermoplastic resin and a radically polymerizable resin usually requires a dispersant such as a solvent or water, which results in a drying process, which increases costs. I don't get it.

[Means for solving problems]

The present invention has been made for the purpose of solving the problems of the prior art as described above, and providing a sublimation type thermal transfer image-receiving paper that can be printed with low energy and does not cause fusion with color sheets. Its composition is that a layer is formed by radiation crosslinking of an oligomer having a radically reactive group, the cured product of which is amorphous and has a glass transition temperature of 65°C or less, on the surface of the base material. It is characterized by:

That is, the present invention involves applying a radiation-crosslinked oligomer having segments that tend to become amorphous onto a base material made of polypropylene film, polyester film, etc., and then crosslinking it to produce a sublimation-type thermal transfer image-receiving paper. The aim is to obtain.

Next, the present invention will be explained in detail.

The sublimation thermal transfer image-receiving paper of the present invention basically has a structure in which a surface layer is formed on a base, similar to conventional products, and this base is made of an appropriate material such as polypropylene film, polyester film, glassine paper, Paper such as coated paper can be used,
Preferably, from the viewpoint of smoothness, a synthetic resin film type material is preferred. In addition, whiteness and opacity may be imparted in advance. In particular, if a porous material such as synthetic paper is used, it not only has good cushioning properties and aids in adhesion to the color sheet, but also has porous properties. This is effective because it promotes the diffusion of the dye.

On the other hand, the coating liquid applied to form the surface layer on the substrate is an oligomer having segments that tend to become amorphous and radically reactive groups, and preferably has a glass transition temperature of 65°C or less after curing. The temperature is preferably 55° C. or lower, and polyurethane, polyester, polyether, and polyamide can be used alone or in combination as segments that tend to become amorphous. Further, as the radically reactive group, those having a vinyl bond such as acrylic and methacryl are preferable.

The above coating liquid may be used alone, but it may also be used with various fillers and additives mixed in for the purpose of improving opacity, writability, antistatic properties, etc. can.

In addition, although it is generally preferable not to use a solvent from the viewpoint of raw material cost and drying energy, from the viewpoint of ease of coating, water or the like may be used as some solvent or dispersion medium. Furthermore, for the purpose of lowering the viscosity of the coating liquid, a vinyl monomer with low viscosity can be mixed and used to the extent that the glass transition point does not rise too much.

In addition, as a coating method, a normal method can be used, and as a curing method, an ultraviolet irradiation method or an electron beam irradiation method can be used.
When using the ultraviolet irradiation method, it is usually necessary to add a known reaction initiator.

[Operation and effect of the invention]

The present invention is as described above, and since a radically polymerizable oligomer whose cured product has a glass transition temperature of 65°C, preferably 55°C or less is used in the coating liquid used to form the surface layer, the transfer temperature is low, and therefore the energy is low. It is possible to print at high speed,
It is possible to print at low voltage and also use paper with low heat resistance.

In addition, since it is not necessary to use the thermoplastic resin used in the above-mentioned known technology, it is possible to coat without using a solvent, which simplifies the coating process. As,
By using a material that has segments that tend to become amorphous and radically reactive groups, the formed surface layer becomes amorphous, making it easy to transfer the coloring material, and the crosslinking between the reactive groups makes it easier to transfer the coloring material. By preventing flow (melting), fusion with the color sheet can be prevented. In particular, by using crosslinking, it is possible to use raw materials with good coloring material transfer properties, which were previously too soft to be used in sublimation type thermal transfer, and it becomes possible to print with low energy.

〔Example〕

Next, embodiments of the present invention will be described.

Implementation row 1 Polypropylene glycol diacrylate (manufactured by Shin Nakamura Chemical Co., Ltd.) was applied to a 100μ polypropylene film (Pearl S film manufactured by Toyobo Co., Ltd.) having a foam layer.
NK ester APG-400) was coated and cured by electron beam irradiation, and the coating thickness was 5 μm. This material was printed using a color sheet coated with a red disperse dye (Sumikalon Red E-FBL, manufactured by Sumitomo Chemical Co., Ltd.) on an 8μ polyester film using ethyl cellulose as a binder, and using a 1cm square thermal head at varying temperatures.

Example 2 Synthetic paper (Peach coat WE-110 manufactured by Nisshinbo)
A mixture of 100 parts of oligoester acrylate (Aronix 6500 manufactured by Toagosei Co., Ltd.) and 5 parts of finely powdered silica (Mizusawa Chemical Co., Ltd. Mizukashiru P-526N) was coated on the mixture, and after curing by electron beam irradiation, Example 1 was prepared. I conducted a similar test.

Example 3 Undercoated with chlorinated polypropylene
A 100μ polypropylene film is coated with urethane acrylate (Aronix M-1200 manufactured by Toagosei Co., Ltd.) dispersed in water using a surfactant.
After drying and curing by electron beam irradiation, the same test as in Example 1 was conducted.

Example 4 A sample of oligoester acrylate (Aronix M-6200 manufactured by Toagosei Co., Ltd.) to which an ultraviolet initiator was added was applied to glassine paper, cured by irradiation with an ultraviolet lamp, and then the same test as in Example 1 was conducted. Summer.

As a result of the tests for each of the above-mentioned examples, high-quality images with better reproducibility of details than conventional products were obtained. In particular, the transparent sheet printed in Example 3 could be used as an overhead projector manuscript.

Comparative example Copolymerized polyester resin (Vitel PE-
200) 90 parts and 100 parts of toluene, methyl ethyl ketone
After coating and drying a coating liquid consisting of 100 parts, Example 1
When printing in the same manner as above, it was observed that the color sheet fused with the color sheet during printing, so from then on, 1 to 20 parts of electron beam curable resin trimethylolpropane trimethacrylate was mixed into the coating solution and applied. However, after drying, we performed a print test on the product that was irradiated with an electron beam, and found that as the amount of trimethylolpropane trimethacrylate increases, the blocking disappears, but the printing temperature increases, and when the amount exceeds 10 parts, the density becomes high. No prints were obtained.

The relationship between head temperature and color density for the above Examples 1 to 4 and Comparative Example is shown in FIG. 1, confirming the effects of the present invention.

[Brief explanation of drawings]

FIG. 1 is a chart showing the relationship between head temperature and color density for an example of the present invention and a comparative example.

Claims (1)

[Claims] 1. A sublimation type photosensitive material characterized in that a layer formed by radiation crosslinking of an oligomer having a radically reactive group, the cured product of which is amorphous and has a glass transition temperature of 65° C. or less, is provided on the surface of a substrate. Thermal transfer image receiving paper.