JP2947534B2 - Thermal transfer recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording medium which enables clear recording on transfer paper having a low surface smoothness or untreated surface paper such as label paper or tag paper.

[0002]

2. Description of the Related Art In recent years,
Printers having a thermal transfer recording system, such as barcode printers and word processors, have been widely used. The thermal transfer recording method has the advantages of easy maintenance and low noise due to the simple apparatus, but the printing quality is easily affected by the smoothness of the surface of the paper to be transferred and the processing condition of the surface, and the surface of the paper having low surface smoothness is low. It is difficult to perform clear recording on transfer paper.

As a method of solving such a defect, a layer composed of a terpene resin having a softening point of 60 ° C. or higher and WAX (see Japanese Patent Application Laid-Open No. H11-12248), a heat-softening resin, A layer comprising a tackifier (see JP-A-1-290495), a vinyl acetate content of 2
A layer comprising 8% or more of ethylene vinyl acetate copolymer (EVA), ethylene ethyl acrylate (EEA), and a derivative thereof (see JP-A-1-290494), or a layer exhibiting tackiness at 60 ° C to 120 ° C. (JP-A-63-6
It has been proposed to provide such a method.

In the case where the above-mentioned resin is applied on the first softening layer which melts by heat, all or a part of an aliphatic or aromatic solvent must be used to dissolve and apply the resin. Must. At this time, in most cases, the first softened layer dissolves or swells and is mixed with the ink layer. This place
In the case, the thermal tackiness of the second softening layer is diluted and reduced.
To, after drying cracks and partial upsurge portion occurs,
The appearance deteriorates, and the sharpness of the printed pattern also decreases. If applied by a method such as an emulsion method, the coating film is not damaged, but the coating film formed in this case lacks mechanical strength and is easily cracked, so that the sharpness of the print is also lowered.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thermal transfer recording medium capable of performing clear printing with little voids even on a transfer paper having low smoothness.

[0006]

The thermal transfer recording medium of the present invention is a thermal transfer recording medium provided with a second softening layer 1c for imparting tackiness to an ink layer (first softening layer) 1b during thermal transfer. , The second softened layer 1c is substantially viscous.
The ink is applied using a solvent that is composed of a tackifier and does not dissolve and swell the ink layer 1b.

[0007]

According to the present invention, for example, as shown in FIG. 1, the second softened layer 1c is substantially composed of a tackifier,
In addition, by using a solvent that does not dissolve and swell the ink layer 1b, clear printing can be performed even on a low-smoothness receiving paper.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the thermal transfer recording medium of the present invention will be described below with reference to FIG. In this example, as shown in FIG. 1, a first softened layer 1b and a second softened layer 1b are provided on one side of a support 1a.
The softening layer 1c is sequentially formed, and the back surface treatment layer 1d is applied to the surface opposite to the support 1a. The second softened layer 1c of this thermal transfer recording medium uses a tackifier that is soluble or dispersible in an organic solvent that does not dissolve and swell the first softened layer 1b.
Since the solvent is not adversely affected by the solvent, the sharpness of the print is maintained, and the use of the above tackifier imparts thermal tackiness to improve transferability.

Next, the structure of the thermal transfer recording medium of the present invention will be specifically described. Support 1 used for thermal transfer recording medium
As a, a film of polyester, condenser paper, polyimide or the like can be used. In this case, a polyester film was used and the film thickness was 4.8 μm.

As the first softening layer, various waxes, ethylene-vinyl acetate copolymer (EVA), tackifier, pigments and fillers can be used. In this case, the following components were used. First softening layer (ink layer) Paraffin wax (mp 65 ° C) 70 parts by weight (HNP-3, manufactured by Nippon Seisaku Co., Ltd.) Ethylene-vinyl acetate copolymer 10 parts by weight (MB-11, manufactured by Sumitomo Chemical Co., Ltd.) Carbon Black 20 parts by weight (MA-100, manufactured by Mitsubishi Kasei Co., Ltd.) Toluene 100 parts by weight A mixture composed of the above components was applied to the support 1a so that the film thickness after drying was 3.5 μm.

As the composition of the second softening layer, terpene phenol, α-methylstyrene / vinyltoluene, rosin and derivatives thereof can be used, and various waxes can also be used for the purpose of adjusting the viscosity. In the present invention,
Is preferably a thermoplastic resin that improves the viscosity of the second softened layer.
Not good. In this example, the following softening layer was used as the second softening layer. Example 1 Terpene phenol (softening point = 115 ° C.) 20 parts by weight (T115, manufactured by Yasuhara Yushi Co., Ltd.) Methyl ethyl ketone (MEK) 80 parts by weight Example 2 Terpene phenol (softening point = 115 ° C.) 16 parts by weight (T115, Yasuhara Yushi Co., Ltd.) Carnauba wax 4 parts by weight (Toyo Petrolite Co., Ltd.) Methyl ethyl ketone (MEK) 80 parts by weight

The solvent methyl ethyl ketone used in Examples 1 and 2 is insoluble in the formulation of the first softening layer. That is, paraffin wax, carnauba wax, ethylene-vinyl acetate copolymer, carbon black, and the like, which constitute the first softening layer, are insoluble in methyl ethyl ketone. In contrast, the terpene phenol used in Examples 1 and 2 dissolves in methyl ethyl ketone. However, since carnauba wax used in Example 2 is insoluble in methyl ethyl ketone, carnauba wax is used by dispersing it in methyl ethyl ketone. Thus, the second
The solvent used for the softening layer is a condition that the components of the first softening layer are not dissolved. However, it is not necessary to dissolve the components of the second softening layer, and it is possible to use an insoluble component. In this case, the components can be used by dispersing the components in a solvent.

On the other hand, in order to compare the characteristics of the samples of Example 1 and Example 2, the following Comparative Examples 1 to 4 were used as the second softened layer.
A sample of Comparative Example 3 was produced. The components are shown below. Comparative Example 1 A case where only the first softening layer was provided without providing the second softening layer. Comparative Example 2 Terpene (YPX800, manufactured by Yasuhara Yushi Co., Ltd.) 20 parts by weight Isooctane (2,2,4-trimethylpentane) 80 parts by weight Comparative Example 3 Ethylene-vinyl acetate copolymer (MB-11, manufactured by Sumitomo Chemical Co., Ltd.) 20 parts by weight 80 parts by weight toluene

The solvent toluene used in Comparative Example 3 dissolves the ethylene-vinyl acetate copolymer component of the second softening layer and the paraffin wax, carnauba wax, etc. of the first softening layer. Further, the solvent isooctane used in Comparative Example 2 dissolves the component of the first softening layer, but does not dissolve the component terpene of the second softening layer. Therefore, the component terpene of the second softening layer was used by being dispersed in isooctane.

A back surface treatment layer 1d is provided on the surface of the support 1a opposite to the surface on which the first softening layer 1b is adhered. The material of the back surface treatment layer 1d is silicon resin, A silicon graft polymer or the like can be used.

An evaluation test was performed on each of the samples of Examples 1 and 2 and Comparative Examples 1 and 3 prepared as described above, in which a bar code pattern was printed on a transfer paper having a low surface smoothness. In addition, an evaluation test of the state of the coating film after application was performed. The evaluation method of the barcode pattern printing and the evaluation method of the state of the coating film after coating are shown below.

Evaluation method of bar code pattern printing Printer: Commercial bar code printer (TEC B-30) Dot density 8 dot / mm Printing speed 50.4 mm / sec Applied energy 0.4 w / dot Evaluation pattern After solid printing The density is measured with a Macbeth densitometer (TR-924). The barcode pattern is visually observed after printing. Transfer paper: Fine paper with a Beck smoothness of 100 seconds

Method for evaluating the state of the coated film after application After the application of the second softened layer, the first softened layer is visually observed for any change such as cracks.

The results of the evaluation tests of Examples 1 and 2 and Comparative Examples 1 and 3 are as shown in Table 1.

[0020]

[Table 1]

First, the solid printing density is 1.35 and 1.55 in Comparative Examples 1 and 2, and in Comparative Example 3, printing is impossible because the second softened layer is stuck to the transfer receiving paper. On the other hand, in Example 1 and Example 2, the print density showed high values of 1.58 and 1.57,
It can be seen that the print density is improved with respect to Comparative Examples 1 to 3.

Next, the clearness of the barcode pattern printing was evaluated. As shown in the barcode pattern column of Table 1, it is assumed that the evaluation is made with ○ and ×, where ○ indicates that the barcode pattern is complete as a result of visual inspection,
× indicates that, as a result of visual inspection, the barcode pattern is partially missing or cannot be printed. As can be seen from Table 1, the bar code patterns in Examples 1 and 2 and Comparative Example 2 were perfect, while Comparative Example 1
In Comparative Example 3, a part of the barcode pattern was missing and unclear, and printing was impossible in Comparative Example 3.

Further, the state of the coating film of the first softened layer after coating was visually evaluated, and the results were represented by ○ and ×. Here, ○ indicates that there is no change in the first softened layer as a result of visual observation, and x indicates that the first softened layer is in a cracked state as a result of visual inspection. As can be seen from Table 1, in Examples 1 and 2, the state of the coating film was good. In Comparative Example 1, the first softened layer was not affected since the second softened layer was not provided. In Comparative Examples 2 and 3, the first softened layer was cracked, and its value as a product was lost.

From the above, when the evaluation results are combined,
In Examples 1 and 2, satisfactory results were obtained in all items of the print density of the barcode pattern, the sharpness of the barcode pattern, and the coating state of the first softening layer. In comparison, Comparative Examples 1 to 3 show unsatisfactory results in any or all of the items.

Accordingly, it can be seen that the thermal transfer recording medium of the present invention can perform clear printing with little voids even on a transfer paper having low smoothness.

It should be noted that the present invention is not limited to the above-described embodiment, but can adopt various other configurations without departing from the gist of the present invention.

[0027]

According to the present invention, there is obtained an advantage that clear printing with few voids can be performed even on a transfer paper having low smoothness.

[Brief description of the drawings]

FIG. 1 is a perspective view used for describing the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermal transfer recording medium 1a Support 1b 1st softening layer 1c 2nd softening layer 1d Back surface treatment layer

Claims (3)

(57) [Claims] 1. A thermal transfer recording medium in which a second softening layer for providing tackiness on an ink layer (first softening layer) during thermal transfer is provided, wherein the second softening layer is substantially Using a solvent that is composed of a tackifier and does not dissolve and swell the ink layer,
A thermal transfer recording medium characterized by being coated. 2. A thermal transfer recording medium in which a second softening layer for providing tackiness on an ink layer (first softening layer) at the time of thermal transfer is provided, wherein the ink layer dissolves and swells in methyl ethyl ketone at room temperature. The thermal transfer recording medium according to claim 1, wherein the second softened layer is composed of only components that are not applied, and the second softened layer is applied using methyl ethyl ketone at room temperature. 3. A thermal transfer recording medium in which a second softening layer for providing tackiness on an ink layer (first softening layer) at the time of thermal transfer is provided. The ink layer dissolves and swells in methyl ethyl ketone at room temperature. A thermal transfer recording medium, wherein the second softened layer is substantially composed of a tackifier, and is applied using methyl ethyl ketone at room temperature.