JPH02269093A - Production of multi-time thermal transfer medium - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Main appearance epithelial skin is established! The present invention relates to a method for manufacturing a thermal transfer medium that improves the sustainability of the quality of multiple prints.

Previously, various non-impact recording methods have been developed, one of which is thermal transfer recording.This thermal transfer recording has low noise, can be recorded on plain paper, and the device is compact and easy to store. Because of its good performance, it has been widely used as printing means in word processors, facsimile machines, label printers, ticket issuing machines, etc.

Conventionally, thermal transfer media used for this thermal transfer recording include those in which a layer of hot-melt ink consisting of a hot-melt binder material and a coloring material is provided on a base film.
It was a one-time type thermal transfer sheet, in which parts of the ink layer that had been printed by multiple thermal transfers remained chipped.

In order to reduce the running cost of this one-time type,
In recent years, various multi-time type thermal transfer sheets have been developed that can perform thermal transfer multiple times on the same sheet.

However, since these multi-time types use the ink in several parts, the first printing density is set low in advance, and the first and second printing density is good. is 3
When printing is performed for the fourth time, the print density decreases and unevenness occurs, resulting in a significant deterioration in print quality.

There have also been attempts to maintain print quality by using a large amount of resin that increases the sustainability of print density, but this resin has the property of becoming less likely to stick to paper when the ink is low, which can cause poor running. It was not possible to perform multiple thermal transfers while maintaining recording quality.

An object of the present invention is to provide a method for producing a multi-time thermal transfer medium that improves the drawbacks of the conventional multi-time type and can provide high initial print density and maintain clear print quality for a longer period of time. That's true.

° ° Ruta's inventors created a thermal transfer medium by dissolving the resin forming the porous layer in a mixed solvent of a good solvent and a poor solvent, and adding a coloring agent to a heat-melting component mainly consisting of polyethylene wax. After finely dispersing the heat-melt ink made by dispersing it and applying it to the base material, do not melt the heat-melt ink in hot air.
Alternatively, in a method for producing a thermal transfer medium in which a part of the medium is dried in a molten state, the ratio of the parent solvent to the poor solvent in the mixed solvent is 5.
/1 to 115, and when drying, if the ratio of poor solvent is high, dry at a low temperature within the above drying temperature range, and when the ratio of parent solvent is high, dry at a high temperature within the above drying temperature range. Found that the above purpose can be achieved when manufactured,
The present invention has now been completed.

In the present invention, the heat-melting component in the ink component is mainly polyethylene wax, but oxidized polyethylene wax, ester wax, α-olefin maleic anhydride, etc. are dispersed in order to improve the dispersibility of the colorant. A wax with good properties may be added, and the amount used is preferably in the range of 50 to 95% by weight of the ink components.

The coloring material can be appropriately selected from commonly used dyes and pigments.

The heat-melting ink used is one in which the heat-melting component and the coloring material are heated and finely dispersed, and then cooled and ground into fine particles of 0.1 to 5 μm.

Examples of resins that form the heat-resistant porous layer include vinyl chloride, vinyl chloride/vinyl acetate copolymers, vinyl resins such as chloride and vinyl/vinylidene chloride copolymers, polyester resins, styrene resins, and polyamide resins. etc. can be mentioned.

The base material used in the present invention is 10 μm made of polyester, polysulfone, polyacetal, polyimide, etc.
The following films are preferred, and in some cases, a stick prevention layer made of a heat-resistant resin may be provided on one side that contacts the thermal head on the opposite side to the ink layer.

In the thermal transfer medium of the present invention, the resin forming the porous layer is dissolved in a mixed solvent for dissolving the resin in which the ratio of the parent solvent to the poor solvent is 571 to 115, and the After adding fine powder of meltable ink and uniformly dispersing it, the thickness of the total solid content is 3 to 15μ (preferably 7μ).
It is manufactured by applying the film onto a substrate to a thickness of ~10μ) and evaporating the solvent to dryness.

In this case, the ratio of the hot-melt ink to the resin capable of forming the porous layer is in the range of 1 to 1.8/1.

Last month - The ratio of hot melt ink to porous resin is 1.0 to 1.8
/ 1, but if the porous resin is more than this ratio, almost no ink will be transferred, and if it is less than this ratio, the ink will be transferred all at once and the print density will not last.

In addition, the ratio of parent solvent and poor solvent in a mixed solvent is such that when the parent solvent increases, the pores of the porous layer formed become thinner and the ink ejection becomes thinner. The ink becomes thick and rough, and the ink tends to come out easily. Therefore, the ratio should be in the range of 5/1 to 115, but if the parent solvent is more than this, the durability will be good, but the ink will not come out easily, and the ink will come out easily. On the other hand, if the amount of poor solvent exceeds this amount, the ink will be excessively discharged, and the ink will be transferred all at once, increasing the one-time quality, resulting in rough printing and poor durability.

Additionally, when drying at low temperatures, heat-melting ink does not melt, so the surface of the recording medium is thinly coated with molten resin, which tends to result in thinner ink flow.On the other hand, when drying at high temperatures, heat-melting ink A portion of the ink becomes molten and is exposed on the surface of the recording medium, resulting in thicker ink ejection (there is a larger amount of ejection).

Therefore, its drying temperature range is 60°C to 90°C
is preferable, but if the temperature is below 60°C, the durability is good, but the ink flow will be poor and the initial density will drop, and if the temperature is above 90°C, most of the heat-melting ink will melt in one heat transfer, so it will last long. As a result, it becomes impossible to carry out multiple thermal transfers, and background stains also occur.

Properties due to changes in the ratio of parent solvent and poor solvent,
There is a correlation between the properties due to changes in drying temperature as shown in the table below, and by this combination, suitable multiple thermal transfers can be obtained.

In other words, if there is a large amount of parent solvent, the temperature should be 90°C instead of the low temperature range.
If there is a large amount of poor solvent, drying at a low temperature slightly above 60°C instead of a high temperature will give a higher initial density and maintain clear print quality, and can be used many times. A suitable thermal transfer recording medium can be obtained in which the ribbon does not stick to the paper and cause poor running.

imperial establishment Next, examples of the present invention will be described.

After heating and finely dispersing the following heat-melting ingredients and colorants,
The mixture was cooled and pulverized to obtain fine particulate heat-melting ink (1).

(The numbers for each component are parts by weight.

Each example below, The same applies to comparative examples.

Dispersant (manufactured by Mitsubishi Kasei ■, P^-3OL) 16.0
Dye (manufactured by Saitari Into Kagaku ■, Nicrosin Ex)
1.4 (Example 1) The following resin was dissolved in a mixed solvent of the following parent solvent and poor solvent, and the heat-melting ink prepared above was added in the following parts by weight and uniformly dispersed. Thereafter, it was coated on a polyester film base material to a thickness of 8 μm and dried in hot air at 90° C. to obtain a thermal transfer medium.

Resin (manufactured by Toyobo ■, Byron 1200) 12.
5 Heat-melting ink 12.5 Ethyl acetate (parent solvent) 37.4 Toluene (poor solvent) 37.3 Activator (Ajinomoto ■, Brain Ac) ALM) 0.3 (Example 2) Drying temperature 60° A thermal transfer medium was obtained in the same manner as in Example 1 except that the material was changed to C.

Resin (manufactured by Toyobo ■, Banjun 5200) 12.5
Hot melt ink 12.5 Ethyl acetate 37.4 Toluene
37.3 activity fl (manufactured by Ajinomoto ■, Brain Act ^LM) 0.3 (Example 3) A thermal transfer medium was obtained in the same manner as in Example 1, except that the parts by weight of each component were changed as shown below. .

Resin (manufactured by Toyobo, Bio:/#200) 12
．． 5 Heat melt ink 12.5 Ethyl acetate 62.2 Toluene
12.5 activator (Ajinomoto ■, Brain Ac) ALM) 0.3 (Example 4) The weight parts of each component were changed as shown below, and the drying temperature was adjusted to 60°C.
A thermal transfer medium was obtained in the same manner as in Example 1 except that the temperature was changed to °C.

Resin (manufactured by Toyobo ■, Byron! 1200) 12.
5 Heat melt ink 12.5 Ethyl acetate 12.5 Toluene
62.2 Activator (Brain Act 8LM, manufactured by Ajinomoto ■) 0.3 When the thermal transfer media of Examples 1 to 4 thus obtained were installed in a normal thermal printer and printed many times, all initial results were Good results were obtained with high density and no extreme decrease in density even in the second and subsequent printings.

In addition, as heat-melting inks, the following (II) to (IV)
When a thermal transfer medium was obtained by changing the composition to the above, and printing was performed with it many times, results similar to those of the above-mentioned example were obtained.

*Hot melt ink (If) Dispersant (manufactured by Mitsubishi Kasei Corporation, PA-3OL) 15.0 Manufactured by Dye Saito Kagaku ■, Nigrosine Ex) 1.0 Manufactured by Oil Black Orient Kagaku ■) 0.0 Oo * Heat-melt ink (III) Dispersant (manufactured by Mitsubishi Kasei ■, PA-3OL) 4.5 Dye (manufactured by Sairi Into Kagaku ■, Nigrosine Ex) 0.5 * Heat-melt ink (IV) Dispersant (manufactured by Mitsubishi Chemical ■, Nigrosine Ex) (manufactured by Kasei ■, PA-3OL) 4.5 Dye (manufactured by Orient Chemical ■, Nigrosine Ex) 0.5 In addition, Vylon #20 is used as a resin to form the porous layer.
Even when 0 was changed to a vinyl chloride/vinyl acetate copolymer (Danka Vinyl IHOOOLTs, manufactured by Denka ■), the same results as in the above-mentioned example were obtained.

Next, a comparative example will be described.

(Comparative Example 1) A thermal transfer medium was obtained in the same manner as in Example 1 except that the drying temperature was changed to 50°C.

(Comparative Example 2) A thermal transfer medium was obtained in the same manner as in Example 1 except that the drying temperature was changed to 100°C.

(Comparative Example 3) A thermal transfer medium was obtained in the same manner as in Example 1, except that the parts by weight of each component were changed as shown below.

Resin (manufactured by Toyobo ■, Byron 1t200) 12.
5 Heat melt ink 12.5 Ethyl acetate 64.0 Toluene
10.7 Activator (Ajinomoto ■, Brain Ac) ALM) 0.3 (Comparative Example 4) The weight parts of each component were changed as shown below, and the drying temperature was adjusted to 60°C.
A thermal transfer medium was obtained in the same manner as in Example 1 except that the temperature was changed to °C.

Resin (manufactured by Toyobo ■, Byron 11200) 12.
5 Heat melt ink 12.5 Ethyl acetate 10.7 Toluene
0.3 (Comparative Example 5) The weight parts of each component were changed as shown below, and the drying temperature was adjusted to 64.0.
A thermal transfer medium was obtained in the same manner as in Example 1 except that the temperature was changed to °C.

Resin (manufactured by Toyobo ■, Banjun 11200) 12.5
Hot melt ink 12.5 Ethyl acetate 62.2 Toluene
12.5 Activator (Brain Ac, manufactured by Ajinomoto) ALM) 0.3 (Comparative Example 6) A thermal transfer medium was obtained in the same manner as in Example 1, except that the parts by weight of each component were changed as shown below. .

Resin (manufactured by Toyobo ■, Byron 1200) 12.5
Hot melt ink 12.5 ethyl acetate 12.5 toluene
62.2 Activator (Ajinomoto ■, Brain Ac) ALM) 0.3 Comparative Examples 1-
When the thermal transfer medium No. 6 was installed in a normal thermal printer and printed many times, the initial density of Comparative Examples 1 and 3.5 was low, and clear printing could not be obtained even after the second printing. Further, in Comparative Examples 2 and 4.6, although the initial density was high, a rapid decrease in density appeared after the third printing, and clear printing could not be maintained.

(Multiple thermal transfer recording density comparison test) Using each of the thermal transfer recording media obtained in Examples 1 to 4 and Comparative Examples 1 to 6, printing was performed multiple times by attaching it to a normal thermal printer. . Each reflection density (
Table 2 shows the test results for OD value).

Note that the reflection density (OD value) was measured using RD920 manufactured by Macbeth Co., Ltd.

(Margins below) Hikari M9: By manufacturing the thermal transfer medium as described above, the present invention has a high initial density and can maintain clear print quality for a longer period of time. A thermal transfer medium that does not stick and cause poor running can be obtained.

Claims (1)

[Claims] A heat-melting ink made by dissolving a resin forming a porous layer in a mixed solvent of a parent solvent and a poor solvent, and dispersing a coloring material in a heat-melting component mainly consisting of polyethylene wax. A method for manufacturing a thermal transfer medium in which the heat-melt ink is finely dispersed, applied to a base material, and then dried in hot air with the heat-melt ink not melted or partially melted. The ratio of poor solvent is set to 5/1 to 1/5, and when drying, when the ratio of poor solvent is high, the drying temperature is low, and when the ratio of parent solvent is high, the drying temperature is high. A method for producing a multiple-time thermal transfer medium, the method comprising drying the medium repeatedly.