JPH10119439A - Heat transfer recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of faulty appearance due to variety, pin hole and the like by a method wherein an ink layer, provided by applying and drying ink, consisting of pigment constituent containing non-aqueous dispersion liquid having the principal constituent of wax, is provided on a substrate while alcohol is employed as the dispersion medium of non-aqueous dispersion liquid. SOLUTION: An ink layer, formed on a substrate by applying and drying, is formed employing ink consisting of pigment constituent containing non- aqueous dispersion liquid having the principal constituent of wax. Alcohol, easy in making emulsion, dispersion and suspension, low in charging property and excellent in safety on applying procedure, is preferably used as the dispersion medium of ink consisting of such non-aqueous dispersion liquid and low- class alcohol, such as ethanol, isopropanol, n-butanol or the like for examples, are used preferably. The application and drying of the ink are excellent and not generating any faulty appearance, such as variety, pin hole or the like, whereby high-quality printing and the like can be effected.

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 for printing on a transfer-receiving member by thermal transfer, and more particularly, to a thermal transfer recording medium having a good appearance of an ink layer and excellent transferability for performing high quality printing. It relates to a recording medium.

[0002]

2. Description of the Related Art In general, a thermal transfer recording medium is constituted by providing a heat-meltable or heat-softening ink layer on a substrate. In use, the medium is heated by a thermal head to melt or soften the ink layer. Printing or the like is performed by thermal transfer onto a transfer target.

[0003] The formation of an ink layer in this type of thermal transfer recording medium is performed by hot-melt coating an ink melted by heating on a substrate, or by dispersing an aqueous pigment dispersion in a dispersion in which components such as wax are dispersed in water. Gravure coat, gravure reverse coat, or roll coat is prepared by dispersing an ink obtained by mixing a liquid or a mixture of a wax and a pigment by melting and dispersing in water. And that's been done.

[0004] In this specification, a dispersion liquid constituting an ink is an emulsion in which small droplets of a liquid are dispersed in a liquid that does not dissolve the liquid, or a dispersion in which fine solid particles are dispersed in a liquid. And emulsions, dispersions and suspensions.

[0005]

However, when an ink composed of an aqueous dispersion is used to form an ink layer on a thermal transfer recording medium, the ink usually has poor wettability to a substrate made of plastic. This is disadvantageous in that, for example, a roll is easily generated and a poor appearance is generated.

Further, if an ink composed of an aqueous dispersion is easily applied by providing an easy-adhesion treatment layer on a substrate made of plastic, the number of manufacturing steps is increased, and the cost is increased. When the thermal head is heated, a part of the ink remains on the substrate side due to excessive adhesion to the plastic substrate, which may lower the transferability. Further, in the case of an ink composed of an aqueous dispersion,
There is also a problem that energy consumed for drying is large and running cost is increased.

The present invention has been made as a result of various studies in view of the present situation. The use of an ink composed of a non-aqueous dispersion containing a wax component as a main component reduces unevenness and pinholes. It is an object of the present invention to provide a thermal transfer recording medium having excellent transferability and capable of performing high-quality printing without causing appearance defects.

[0008]

The thermal transfer recording medium of the present invention has an ink layer formed by applying and drying an ink composed of a non-aqueous dispersion containing a pigment component containing wax as a main component on a substrate. Alcohol is used as a dispersion medium for the non-aqueous dispersion.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, an ink layer formed by coating and drying on a substrate is formed using an ink comprising a non-aqueous dispersion containing a pigment component containing wax as a main component. Since an organic solvent having a low surface tension and a small contact angle on a plastic substrate as compared with water is used as a medium, it can be uniformly applied on the substrate, resulting in unevenness and pinholes. As a result, appearance defects do not occur.

In addition, since there is no need to provide an easy-adhesion treatment layer on a plastic substrate and drying is easy,
It can be manufactured at low cost, can perform good thermal transfer with a thermal head, has excellent transferability, and can perform high quality printing.

On the other hand, when an ink composed of an aqueous dispersion containing water as a dispersion medium is used, since the surface tension of water is high and the contact angle on a plastic substrate is large, it is necessary to apply the ink uniformly. It is difficult, and unevenness and pinholes are generated, and poor appearance is likely to occur.

The ink composed of such a pigment-containing non-aqueous dispersion containing a wax as a main component is preferably produced by mixing a commercially available non-aqueous wax emulsion with a commercially available non-aqueous pigment dispersion. The pigment component may be dispersed in a non-aqueous solvent using a suitable dispersant, and a commercially available non-aqueous wax emulsion may be mixed therewith to produce the pigment component.
It may be produced by dispersing a mixture of necessary components such as a pigment component, a wax, a resin component and a dispersant in a non-aqueous solvent.

As a dispersion medium of the ink comprising such a non-aqueous dispersion, an alcohol which is easy to emulsify, disperse and suspension, has low chargeability, and is excellent in safety in a coating process. It is preferred to use, for example, ethanol, isopropanol, n-
Lower alcohols such as butanol are preferably used.

As the wax, carnauba wax, paraffin wax, polyethylene wax, microcrystalline wax, candelilla wax, esters and amides of higher fatty acids and the like are preferably used.

Further, as a composition component of the ink, a resin component for improving durability of heat-transferred printing and the like is generally used in combination with a wax for mainly improving thermal transferability. Resin components used in combination include polyester resin, polyamide resin, polyurethane resin, acrylic resin, ethylene-vinyl acetate copolymer, cellulose resin, rosin resin, petroleum resin, etc., which are dissolved in the non-aqueous solvent used. Alternatively, a dispersible material is used.

The pigment component may be an organic substance or an inorganic substance. For example, in addition to a coloring agent such as carbon black, phthalocyanine blue and titanium dioxide,
Any substance such as a magnetic substance and a fluorescent substance can be used.

Further, the dispersing agent for dispersing the pigment component may be any one which is soluble in the non-aqueous solvent used.
It can be used without any particular limitation. For example, styrene-acrylic resin, polyacrylic acid and the like are preferably used.

As a substrate on which such an ink layer is provided, a plastic film such as polyethylene terephthalate, polyethylene naphthalate, or polyimide is preferably used.

In manufacturing such a thermal transfer recording medium, a heat-resistant back layer may be provided on the side of the substrate opposite to the surface on which the ink layer is formed, if necessary, to protect the substrate.

[0020]

Next, an embodiment of the present invention will be described. Example 1 MINIK MHI Black # 217 (manufactured by Mikuni Dyestuffs Co., Ltd .; 15 parts by weight of carbon black; isopropanol dispersion of solid black: 35% by weight) Slip Aid SL-508 (manufactured by San Nopco Co .; -Valamide 725 (manufactured by Henkel Hakusui; polyamide resin) 5 〃 Quinton 1700 (manufactured by Zeon Corporation; petroleum resin) 2 イ ソ Isopropanol 12.5 〃 Mix this composition for 1 hour By dispersing, a dispersion liquid for forming an ink layer was prepared.

The dispersion for forming an ink layer was coated with a 4.5 μm thick liquid.
m was coated on a polyethylene terephthalate film having a thickness of 3 μm after drying, dried to form an ink layer, and slit to a constant width to prepare a thermal transfer recording medium.

Example 2 Minik MHI Black # 971 (manufactured by Mikuni Shikisha; 15 parts by weight of carbohydrate isopropanol dispersion of black; solid content 30% by weight) Hidisper 1535 (manufactured by Gifu Shellac Manufacturing Co .; Carna 70) 〃 Uba wax isopropanol emulsion, solid content: 15% by weight) Hiflat A-20P-1 (manufactured by Gifu Shellac Manufacturing Co., Ltd .; polyethylene wax isopropanol emulsion, solid content: 20% by weight) KR-610 ( 5% isopropanol 10.5% This composition was mixed and dispersed for 1 hour to prepare a dispersion for forming an ink layer.

The dispersion for forming an ink layer was coated with a 4.5 μm thick liquid.
m was coated on a polyethylene terephthalate film having a thickness of 3 μm after drying, dried to form an ink layer, and slit to a constant width to prepare a thermal transfer recording medium.

Example 3 90 parts by weight of Taipure R900 (manufactured by DuPont; titanium dioxide) Joncryl 682 (manufactured by Johnson Polymers, styrene-10 ア ク リ ル acrylic resin) isopropanol 100〃 This composition was ball milled for 10 minutes. The mixture was mixed and dispersed for a time to prepare a dispersion.

Then, using the obtained dispersion, 150 parts by weight of the dispersion was used. Hidisper-1535 (manufactured by Gifu Shellac Manufacturing Co., Ltd .; carna 150〃 isopropanol emulsion of Ubawax, solid content 15% by weight) KR-610 ( Arokawa Chemical Industry Co., Ltd .; rosin resin) 4 〃Quinton 1700 (Nippon Zeon Co., Ltd .; petroleum resin) 2 イ ソ isopropanol 25.5 〃 The composition was mixed and dispersed for 1 hour to prepare a dispersion for forming an ink layer.

The dispersion for forming an ink layer was coated with a 4.5 μm thick liquid.
m was coated on a polyethylene terephthalate film having a thickness of 3 μm after drying, dried to form an ink layer, and slit to a constant width to prepare a thermal transfer recording medium.

COMPARATIVE EXAMPLE 1 Minik SA Black # 0898 (manufactured by Okuni Shikisha; 15 parts by weight of carbohydrate; 30% by weight of an aqueous dispersion of black) Hydrine P-7 (manufactured by Chukyo Yushi; water of paraffin wax 35) Nosecoat PEM-17 (manufactured by San Nopco; polyethylene wax 10% aqueous emulsion solids 40% by weight) Cellosol D-101 (manufactured by Chukyo Yushi; rosin-based resin) Aqueous 4% emulsion solid content 50% by weight) Vironal MD-1200 (manufactured by Toyobo Co., Ltd .; polyester tree 6% aqueous emulsion of resin 34% by weight) water 22.5% This composition was mixed and dispersed for 1 hour to form an ink layer. A dispersion for formation was prepared.

The dispersion for forming an ink layer was coated with a 4.5 μm thick liquid.
m was coated on a polyethylene terephthalate film having a thickness of 3 μm after drying, dried to form an ink layer, and slit to a constant width to prepare a thermal transfer recording medium.

The appearance of the ink layer of the thermal transfer recording medium obtained in each of the examples and comparative examples was observed, and the unevenness and pinhole were visually determined. Judgment is uneven, pinho
The case where no holes or the like were observed was indicated by (○), the case where slight unevenness or pinholes were observed was indicated by (△), and the case where unevenness or pinholes were clearly observed was indicated by (x).

A thermal transfer bar code printer was prepared by using the thermal transfer recording media obtained in each of the examples and comparative examples.
(Manufactured by Sato Corporation; M-4800), printing was performed on white coating paper for Examples 1 and 2 and Comparative Example 1, and on black coating paper for Example 3, and the printing quality was visually checked. Judged. In the judgment, the case where no missing or missing printing was recognized was represented by (○), and the case where missing or missing printing was observed was represented by (x). Table 1 below shows the results.

[0031]

[0032]

As is clear from Table 1 above, Example 1
The thermal transfer recording media obtained in Comparative Examples 1 to 3 did not show much unevenness, pinholes, etc., had a good appearance of the ink layer, and had good printability, as compared with the thermal transfer recording media obtained in Comparative Example 1. No loss or chipping was observed, and the printing quality was good. Therefore, according to the present invention, the ink was applied and dried well, and high quality was obtained without causing appearance defects such as unevenness and pinholes. It can be seen that a thermal transfer recording medium having excellent transferability for performing printing and the like can be obtained.

Claims (2)

[Claims] 1. A thermal transfer recording medium having an ink layer provided by applying and drying an ink comprising a non-aqueous dispersion containing a pigment component containing wax as a main component on a substrate. 2. The thermal transfer recording medium according to claim 1, wherein the dispersion medium of the non-aqueous dispersion is an alcohol.