JPH02103182A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To eliminate the release of a transfer layer due to the application of high energy and to transfer a high density image by providing an adhesive layer based on an acrylic resin having a specific MW between a polyester film and the transfer layer. CONSTITUTION:An adhesive layer 2 based on an acrylic resin having an MW of 10,000-400,000 is provided to a support 1 composed of a polyester film and a transfer layer 3 containing a heat-sensitive sublimable dye or meltable evaporation transfer dye is further provided. When the MW of the acrylic resin of the adhesive layer is below 100,000, heat resistance is insufficient and adhesiveness is damaged by heating at the time of transfer. When said MW exceeds 400,000, the resin becomes hard and the adhesiveness to a base material is damaged and the resin becomes hard to dissolve in a solvent. Since this thermal transfer recording medium is characterized in that the adhesive layer is hardly dyed with the dye of the transfer layer, transfer efficiency to a receiving body becomes well and the density of a transfer image is enhanced. Even in the case of transfer by high printing pressure and energy, the transfer of the resin of the transfer body to the receiving body is not performed and a high grade transfer image can be formed.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention uses a heat-generating recording member such as a thermal head or a thermal vane to transfer a sublimable dye or a melt-evaporation migration dye to a transfer target. The present invention relates to a thermal transfer recording medium used in a method for recording images.

<Prior art> Heat-sensitive sublimation or melt-evaporation migration disperse dyes or oil-soluble dyes are used as a means for printing video images, computer graphics images, etc. using a heat-generating recording member such as a thermal recorder or a thermal pen. There is a technique of using a heat-sensitive recording medium in which a transfer layer containing a heat-sensitive recording medium is provided on a base sheet, and superimposing and transferring this onto a transfer target.

In order to transfer a video image or a computer graphic image with high quality, it is desirable that color development with high density can be obtained by the transfer. For this reason, methods are used in which strong pressure is applied or high printing energy is applied when the thermal transfer recording medium and the transfer target are overlapped and transferred. At this time, the polyester film that is the base material of the thermal transfer recording medium,
If an adhesive layer is not provided between the transfer layers containing heat-sensitive sublimation dyes or melt-evaporation migration dyes, the binder resin in the transfer layer may also be transferred to the transfer target and damage the transferred image. One method is to provide an adhesive layer between the base material and the transfer layer. As the material for the adhesive layer, a material that has adhesive properties for both the polyester film as the base material and the binder resin for the transfer layer is selected, but since butyral resin is mainly used as the binder for the transfer layer, polyester is usually used. Resin is used. This adhesive layer can prevent the transfer of the binder resin in the transfer layer to the transferred object, but on the other hand, because the polyester resin is dyeable, some of the dye in the transfer layer is adsorbed to the adhesive layer during transfer. This has the disadvantage that less dye transfers to the transfer object, resulting in lower image density.

<Problem to be solved by the invention> The present invention has been made in view of the above circumstances.
To provide a thermal transfer recording medium that does not cause peeling of the transfer layer even when high energy is applied by a heat-generating recording member, and that allows the transfer of high-density images because the dye in the transfer layer is not adsorbed to the adhesive layer during transfer. This is the purpose.

Means for Solving the Problems> As a result of various studies to achieve the above objectives, we have found that a polyester film with a molecular weight of 100,000 to
The present inventors have found that good results can be obtained by providing an adhesive layer mainly made of 400,000 acrylic resin and further providing a transfer layer containing a heat-sensitive sublimation dye or a melt-evaporation migration dye. As a result of experiments, acrylic resin has the property of being less stained with dyes than polyester resin, and when this is used as an adhesive layer, the amount of dye in the transfer layer 4 is reduced, and the transfer material is less likely to be dyed. It was found that this method has the effect of increasing transfer efficiency. As the acrylic resin, homopolymers or copolymers of acrylic acid, acrylic esters, acrylamide, acrylonitrile, methacrylic acid, methacrylic esters such as methyl methacrylate, ethyl methacrylate, and propyl methacrylate can be used.

Further, in order to improve the coating suitability of the acrylic resin of the adhesive layer and the adhesion with the transfer layer, a filler such as finely powdered silica having a particle size of 0.5 to 5 μm may be added.

Depending on the printer model, particularly high printing pressure and energy may be applied to the transfer recording medium, and the adhesive layer may be required to have particularly strong adhesive strength.

In this case, acrylic resin or polyester copolymer is used as the main material, or acrylic resin has 1 to 20%
% of the polyester resin can improve the adhesion of the adhesive layer to the polyester film of the base material.

The reason why the molecular weight of the acrylic resin for the adhesive layer is limited to 100,000 400,000 is because if the molecular weight is less than 100,000, heat resistance will be insufficient and adhesiveness will be impaired by heating during transfer. This is because if it exceeds 10,000, the resin becomes hard, its adhesion to the base material is impaired, and it becomes difficult to dissolve in solvents. The thickness of this adhesive layer is preferably 2.0 μm or less, which means that
This is because if the thickness exceeds 2.0 μm, energy from the heat-generating recording member is absorbed by the adhesive layer during transfer, resulting in a reduction in the transfer density to the transfer target.

As the object to be transferred, a synthetic paper having a thickness of 60 to 250 .mu.m or a polyester film colored milky white is used as the object to be transferred, and an image receiving layer mainly made of polyester resin is provided on the surface thereof. The reflection density at this time is O, OS ~ 0.2
It is 0.

<Effects of the Invention> In the thermal transfer recording medium of the present invention, since the adhesive layer is not easily stained by the dye of the transfer layer, the transfer efficiency to the transfer object is good and the density of the transferred image is high. Further, even when transferring with high printing pressure and energy, no resin transfer of the transfer layer to the transfer object is observed, making it possible to create a high-quality transferred image.

<Example> Preferred embodiments of the present invention will be described below.

The following composition was applied as an adhesive layer to a polyester film (manufactured by Diafoil ■, Diafoil 6#) at a ratio of Ig/Po.

The molecular weight of acrylic resin BR-102 is 320,000.

Further, 20 parts by weight of the following composition was coated thereon as a transfer layer at a rate of 2 g/po.

The obtained thermal transfer recording medium was transferred to a thermal head (300
The reflection density was as high as 1.90 as a result of transfer to the object with an applied voltage of 13 V and a duration of 4.5 ms during the pulse.
No resin transfer to the transfer layer was observed.

Comparative Example> A thermal transfer recording medium was produced in the same manner as in the example except that the acrylic resin was replaced with a polyester resin (Unitika Elitel 083500). In the printed matter using this, no resin transfer was observed in the transfer layer, but the reflection density was 1.63.
The quality of the image could not be said to be good.

[Brief explanation of the drawing]

FIG. 1 is a sectional view schematically explaining an embodiment of the present invention. ■...Polyester film■...Adhesive layer■...Transfer layer Application Application: Jintoppan Printing Co., Ltd. Toyo Ink Manufacturing Co., Ltd.

Claims (1)

[Claims] It is characterized in that an adhesive layer mainly made of acrylic resin with a molecular weight of 100,000 to 400,000 and an ink layer containing a heat-sensitive sublimation dye or a melt-evaporation migration dye are laminated in this order on a polyester film. Thermal transfer recording medium.