JPH022080A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To prevent release by enhancing the adhesive strength with a color material layer and to prevent the generation of blocking during a manufacturing process by adding a blocking preventive additive to a resin forming an intermediate adhesive layer. CONSTITUTION:A thermal transfer recording medium 11 is constituted by providing an intermediate adhesive layer 15 and a color material layer 3 on a support 15. The support 1 is formed from a polyester film and the color material layer 3 is formed by adding a fine powdery filler 5 to a component 4 consisting of a low m.p. heat-meltable wax and a color material. The intermediate adhesive layer 15 is formed by adding a blocking preventing additive to a resin containing at least a polyester resin. As the additive, cobalt soap, cobalt naphthenate, cobalt octenate, cobalt stearate or the like are designated. Since the intermediate adhesive layer 15 is formed by mixing other resin, for example, a polyamide resin with the polyester resin, the adhesive strength with the color material layer 3 is enhanced and the release at the interface of the intermediate adhesive layer 15 and the color material layer 3 can be prevented. Further, the blocking generated when the support 1 taken up in a roll shape is delivered can also be prevented.

Description

[Detailed Description of the Invention] [Summary] A coloring material in which an intermediate adhesive layer is provided on a support, and a fine powder filler is added to an ink component consisting of a low melting point hot-melting wax and a coloring material. Regarding thermal transfer recording media with layers, the purpose of this is to increase the adhesive strength between the coloring material layer and the intermediate adhesive layer to prevent film peeling, and to prevent blocking during the manufacturing process. In a thermal transfer recording medium, an intermediate adhesive layer containing at least a polyester resin is provided, and a coloring material layer is further provided thereon, in which a fine powder filler is added to an ink component consisting of a low melting point heat-melting wax and a coloring material, The structure is such that an additive for preventing blocking is added to the resin forming the intermediate adhesive layer.

[Industrial application field]

The present invention is a thermal transfer recording medium in which an intermediate adhesive layer is provided on a support, and a coloring material layer is further provided on the intermediate adhesive layer on which a fine powder filler is added to an ink component consisting of a low melting point heat-melting wax and a coloring material. Regarding.

To perform printing using this type of thermal transfer recording medium, a thermal head equipped with a large number of heating resistors is used. During printing, electricity is applied to the heating element in a predetermined pattern, and the coloring material is melted by the heat of the heating element and transferred onto the recording paper to form an image.

[Conventional technology]

Conventionally, the intermediate adhesive layer interposed between the support and the heat-melting color material layer has been made of polyester resin, vinyl chloride, vinyl acetate copolymer, or acrylic resin.

Vinyl chloride resin (JP-A-55-105579),
Polyamide resin (JP-A-56-116193),
Polyvinyl butyral resin, epoxy resin (JP-A-57
36698) and a saturated linear polyester resin (Japanese Unexamined Patent Publication No. 59-96992).

[Problem to be solved by the invention]

However, since conventional heat-melting coloring material layers are mainly made of relatively low-molecular materials such as wax, materials with particularly high molecular weight or glass transition temperature (Tg ) When using a polyester resin with a high
Conventional supports made of polyester resin etc. are bonded between polymeric materials and have a high adhesive strength.
Since the adhesive between the heat-melting coloring material layer is between a low-molecular material and a polymeric material, the adhesive force is weak, and as shown in FIG. The film is likely to peel off at the interface A with layer 2. As a result, when printing is attempted many times using the thermal transfer recording medium 10, many places are missing in the second and subsequent printings, resulting in a significant deterioration in print quality. 4 is an ink component, and 5 is a filler.

In addition, in order to prevent such film peeling between the coloring material layer 3 and the intermediate adhesive layer 2, among the conventional intermediate adhesive layer materials, a polyester resin with a relatively low molecular weight or a low glass transition temperature (Tg) is used. If this is used, the adhesive force with the coloring material layer 3 is improved, but a so-called blocking problem occurs in the process of coating the intermediate adhesive N2 onto the support 1. That is, when the intermediate adhesive layer 2 is applied and the support l wound up into a roll is unwound, blocking occurs in which the intermediate adhesive layer 2 adheres to the support 1 wound inside. This is considered to be because the adhesive force of the intermediate adhesive layer 2 itself becomes high because the constituent resin material has a relatively low molecular weight and is difficult to harden, or because the resin becomes plastic at a temperature higher than the glass transition.

The object of the present invention is to increase the adhesive strength between the coloring material layer and the intermediate adhesive layer to prevent film peeling and to prevent blocking during the manufacturing process.

[Means to solve the problem]

In order to achieve the above object, the present invention provides an intermediate adhesive layer containing at least a polyester resin on a support, and further fills fine powder with an ink component consisting of a low-melting point hot-melt wax and a coloring material. In a thermal transfer recording medium provided with a coloring material layer containing a coloring material, an additive material for preventing blocking is added to the resin forming the intermediate adhesive layer.

Additives include cobalt soap and cobalt naphthenate.

Examples include cobalt octylate and cobalt stearate.

6 Effect] Additives to prevent blocking are added to the intermediate repellent layer containing polyester resin, which has strong adhesion to the support but weak adhesion to the coloring material layer, so the coloring material is added to the intermediate adhesive layer. Even if a low-molecular resin or a resin having a low glass transition point is mixed in order to improve adhesion with the layer, blocking, which has been a problem in the past, can be prevented in this case.

〔Example〕

The present invention will now be described in detail with reference to FIGS. 1 and 2.

FIG. 1 is a side view showing the state of use of a thermal transfer recording medium to which the present invention is applied, and in the figure, 11 is a thermal transfer recording medium;
2 is a thermal head, 13 is a platen, and 14 is a recording paper.

The thermal transfer recording medium 11 has an intermediate adhesive layer 15 on the support 1.
It is configured by providing two color material layers 3. The support 1 and the coloring material layer 3 are the same as those shown in FIG. 3, and the support 1 is made of a 3.5 μm thick polyester film, and the coloring material layer 3 is made of a low melting point heat-melting wax and a coloring material. A fine powder filler 5 is added to the ink component 4. The intermediate adhesive layer 15 is made of a resin containing at least a polyester resin and an additive for preventing blocking. Additives include cobalt soap and cobalt naphthenate.

Examples include cobalt octylate and cobalt stearate.

As described above, since the intermediate adhesive layer 15 of the present invention has a resin composition in which a polymeric polyester resin is mixed with another resin, such as a polyamide resin, the adhesive force with the color material layer 3 is improved, and the conventional problem is solved. It is possible to prevent the film from peeling off at the interface between the intermediate adhesive layer 15 and the coloring material layer 3. Further, since an additive material for preventing blocking is added to the intermediate adhesive layer 15, it is possible to prevent blocking that occurs when the intermediate adhesive layer 15 is coated and the support 1 wound up into a roll is fed out. can.

Next, experimental results regarding these effects will be shown.

For the experiment, thermal transfer recording media having two types of compositions (1) and (2) shown in Table 1 below were prepared.

To form the front and intermediate adhesive layers, each of the above compositions was applied onto a 3.5 μm thick polyester film (Support 1), air-dried, and wound around a 1-inch core with a torque of 1 kg-am. Ta. The dry film thicknesses obtained were 2.0 μm for both (1) and (2). After leaving this for 7 days, when we tried to unroll each support, we found that support (■) with cobalt stearate added could be easily unwound, but support (■) without cobalt stearate was able to be unwound easily. was unable to perform due to so-called blocking.

Next, on the support 1 on which the intermediate adhesive N15 having the composition (2) above was formed, the composition for the coloring material layer was applied with a wire spar, and after air drying, a 10.0 μm heat-melting coloring material layer was applied. was formed. The thus obtained thermal transfer recording medium for multiple printing is mounted on a thermal printer, and the recording energy is 4
Solid printing was repeated three times at the same location on this thermal transfer recording medium at a rate of 0.0 mJ/mm''.The recording paper used had a Beck smoothness of 300 seconds.As a result, the color material layer 3
There was no peeling of the film, and high-density printing was possible with little loss of density even when three characters were printed. Figure 2 is a graph showing the change in recording density during printing, and the horizontal axis is the number of repetitions.
The vertical axis is the recording density (optical reflection density 0.0.).

Table 2 below shows the results of experiments conducted by varying the amount of cobalt stearate (2) in the intermediate adhesive layer in Table 1.

Table 2 The amounts of cobalt stearate added in Table 2 are 90 parts by weight of toluene and 4 parts by weight of polyester resin.

This is the amount added to 3\i parts of polyamide resin.

In addition, each symbol in the table indicates the following content.

■ = Very good O: Good ×: Bad = Problematic △: Between ○ and × (lowest usable condition) From Table 2, the amount of additives added is 0.1 to 40%, preferably 1 to 10
It can be seen that good results can be obtained in the range of %. If the amount added is less than 0.1%, blocking will occur, and 4
When it is 0% or more, a problem arises in that the adhesive force to the heat-melting coloring material layer 3 decreases. The addition amount O is shown in Table 1. ■
This corresponds to the case of (conventional).

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain a heat-sensitive transfer recording medium in which the intermediate adhesive layer has high adhesive strength with the support and the heat-sensitive melting coloring material layer, and which prevents blocking in the intermediate adhesive layer forming step. . Therefore, the thermal transfer recording medium of the present invention has advantages such as high long-term storage stability and suitability for multiple printing.

[Brief explanation of the drawing]

Fig. 1 is a side view showing the state of use of a thermal transfer recording medium to which the present invention is applied, Fig. 2 is a characteristic diagram of a thermal transfer recording medium according to an embodiment of the present invention, and Fig. 3 is a conventional thermal transfer recording medium. This is a diagram illustrating problems with the medium. In the figure, 1 is a support, 3 is a coloring material layer, 4 is an ink component, 5 is a filler, 11 is a thermal transfer recording medium, and 15 is an intermediate adhesive layer.

Claims (1)

[Claims] An intermediate adhesive layer (15) containing at least a polyester resin is provided on the support (1), and an ink component (4) consisting of a low-melting point hot-melt wax and a coloring material is further coated with a fine powder filler (5). ) A heat-sensitive transfer recording medium provided with a coloring material layer (3) to which a blocking prevention additive is added to the resin forming the intermediate adhesive layer (15).