JPH03218892A - Thermal transfer recording material - Google Patents

Abstract

PURPOSE:To obtain good printing capacity even on general paper without using exclusive highly smooth paper by forming a uniform dispersion state of an ethylene/vinyl acetate copolymer to a heat-meltable ink layer. CONSTITUTION:As a base material, papers such as glassine paper or condenser paper or plastics such a polyester, polycarbonate, polyimide or polyamide can be used. The heat-meltable ink layer provided on the base material is based on a heat-meltable binder, an ethylene/vinyl acetate copolymer forming a uniform dispersion state, a softening material and a colorant. In order to bring the ethylene/vinyl acetate copolymer to a uniformly dispersed state being an intermediate state between the compatible and separated states of the heat- meltable binder without bringing the same to a state compatible with or separated from the heat-meltable binder, the polarity of the ethylene/vinyl acetate copolymer and that of the heat-meltable binder are adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a thermal transfer recording material used in a thermal transfer recording device such as a thermal printer.

(Prior Art) In recent years, with the rapid development of the information industry, various information processing systems have appeared, and recording methods and devices suitable for each information processing system have been developed.

One such recording method involves bringing the recording paper into contact with the heat-melting ink layer of the thermal transfer type recording material, applying pressure, and then bringing a thermal head into contact with the back side of the base material to apply pulsed electricity to the head. There is a thermal transfer recording method that prints by sending a signal and heating the head to transfer the heat-melting ink on the heated area of the thermal transfer layer.
Recently, it has become increasingly popular because the equipment used is lightweight, compact, noiseless, and has excellent operability and maintainability.

(Problem to be Solved by the Invention) However, since this method basically uses a printing method that involves contact between recording paper and thermal transfer type recording material, when highly smooth paper is used as the recording paper, This is not a problem, but if you use general paper with a highly uneven surface (e.g., high-quality paper, dry copying machine paper, etc.), the print will be unclear (e.g., some of the characters will be missing), and the However, this method had the disadvantage of requiring the use of specialized highly smooth paper.

(Means for Solving the Problems) The present invention was made in view of the above-mentioned circumstances, and as a result of intensive research to obtain good printing performance even on general paper without using special highly smooth paper. By designing a heat-melting ink to form a crosslinked structure between the convex portions of highly uneven general paper, we have discovered that it is possible to print on general paper, and as a means for forming the crosslinked structure, we have developed the It was discovered that the most suitable one was one in which a hot-melt ink layer was formed in a uniformly dispersed state of ethylene-vinyl acetate copolymer, and the present invention was finally completed. The present invention provides a heat-sensitive transfer recording material comprising at least a heat-melt ink layer, characterized in that an ethylene-vinyl acetate copolymer is uniformly dispersed in the heat-melt ink layer. It is something to do.

The present invention will be explained in detail below.

As the base material in the present invention, papers such as glassine paper and capacitor paper, or plastics such as polyester, polycarbonate, polyimide, and polyamide can be used.

The heat-melt ink layer provided on the base material is mainly composed of a heat-melt binder, a uniformly dispersed ethylene-vinyl acetate copolymer, a softener, and a coloring material.

Heat-melting binders include petroleum waxes such as paraffin wax and microcrystalline wax, non-polar waxes such as polyethylene wax, moderately polar waxes such as candelilla wax, carnauba wax, wood wax, beeswax, Highly polar waxes such as ester waxes and higher fatty acids such as stearic acid, palmitic acid, lauric acid, aluminum stearate, zinc palmitate, glycerol monohydroxystearate, oleic acid amide, stearic acid amide, and lanolin fatty acids; Those with large polarity such as metal salts, esters, amides, and other derivatives are 1
It can be used in different types or in a mixture of two or more types.

The feature of the present invention is that the ethylene-vinyl acetate copolymer is uniformly dispersed in the hot-melt ink layer. A state in which fine particles are uniformly scattered. Therefore, in order to uniformly disperse the ethylene-vinyl acetate copolymer in the heat-fusible ink layer, the polarity of each must be adjusted so that the ethylene-vinyl acetate copolymer and the heat-fusible binder do not dissolve or separate. There is a need.

For example, when a non-polar wax is used as a hot-melt binder, an ethylene-vinyl acetate copolymer with a vinyl acetate content of 30% or less (low to medium polarity) will be miscible, resulting in a uniform A highly polar ethylene-vinyl acetate copolymer with a vinyl acetate content exceeding 30% is not compatible with the ethylene-vinyl acetate copolymer, and separation of the ethylene-vinyl acetate copolymer occurs, resulting in the desired uniformity. A well-distributed state cannot be obtained. That is, in general, substances with close polarities have good compatibility, and substances with far polarities have poor compatibility.

On the other hand, the polarity of heat-melting binders is determined by waxes that have no polarity such as petroleum wax, waxes that have polarity due to having ester bonds, OH groups, or free fatty acids in their molecules, or higher fatty acids and their metal salts. It can be adjusted arbitrarily by mixing surfactants, etc. The polarity of the ethylene-vinyl acetate copolymer changes depending on the vinyl acetate content, and as the vinyl acetate content increases, the polarity decreases. The polarity decreases as the vinyl acetate content decreases. Therefore, in order to make the ethylene-vinyl acetate copolymer compatible with the heat-melting binder or to achieve a uniform dispersion state that is an intermediate state between the two, the polarity of the ethylene-vinyl acetate copolymer and the thermal By adjusting the polarity of the meltable binder, a desired uniform dispersion state can be obtained.

Ethylene-vinyl acetate copolymers used in the present invention include EVAFLEX 150 (vinyl acetate content: 33 wt%, the same applies hereinafter), EVAFLEX 40Y (41 wt%)
), 45X (46wt%), 220 (28wt%)
%), 260 (28wt%), 360 (25w
t%), 420 (19wt%), 460 (19wt%)
wt%) (manufactured by Mitsui DuPont Bolichemical ■), Solex BH (55wt%), Solex CH (60wt%)
%), DI (67wt%), DH (67wt%)
, FH (87wt%), BI (55wt%),
The same CI (60wt%) (manufactured by Nippon Gosei Kagaku Kogyo ■)
, NUC copolymer MB 080 (19 wt%), MB-850 (22 wt%), MB-010 (2
5 wt%) and MB-030 (27 wt%) (manufactured by Nippon Unica Ichiichi), but the present invention is not limited to these and can be used. When a highly polar ethylene-vinyl acetate copolymer, specifically one with a vinyl acetate content of more than 30 wt%, is used, the heat-melting binder is mainly composed of non-polar wax and contains less than 30 wt% of vinyl acetate. In the case of substances, the main component is one with high polarity.

The amount of the ethylene-vinyl acetate copolymer used is preferably 5 to 15 parts by weight per 100 parts by weight of the hot-melt ink, and two or more of these can also be used in combination.

Examples of the flexible material include resins such as petroleum resin, polyvinyl acetate, polystyrene, styrene-butadiene copolymer, and acrylic resin.

Colorants include black pigments such as various grades of carbon black, yellow pigments such as Benzidine Yellow, Hansa Yellow, and Zinc Yellow, red pigments such as Permanent Rat 4R, Rhodamine Lake P, and Brilliant Carmine 6B, Victoria Blue Lake, and Phthalocyanine Blue. , Fast Sky Blue, and other blue pigments are used.

The amount of each component used in the hot-melt ink layer is based on the total weight of 1
00 parts, 30 to 80 parts of heat-melting binder, 5 to 15 parts by weight of ethylene-vinyl acetate copolymer, 3 to 10 parts of softener
It is preferable to use 20 parts and 5 to 20 parts of colorant, and small amounts of antioxidants, dispersants, lubricants, etc. may also be added.

The heat-sensitive transfer type recording material of the present invention is prepared by preparing a heat-melting ink using a well-known mixing and dispersing machine such as a heated triple roll or an attriter using each of the above-mentioned components, and then using the heat-melting ink as it is or in a suitable form. By applying the dispersed product to a base material at a coating thickness of 2 to 15 μm using various coating methods such as roll coating, fountain coating, gravure coating, and screen coating. Obtainable.

In the present invention, it goes without saying that a release layer may be further provided between the base material and the heat-fusible ink layer, and a heat-resistant layer may be provided directly in front of the base material.

(Function) In particular, in the present invention, since fine particles of ethylene-vinyl acetate copolymer are uniformly dispersed in the heat-melting ink layer, when printing on general paper with a highly uneven surface, these fine particles can Since the heat-melting ink layer acts as a bridge between the two, the heat-melting ink layer also covers the concave portions, and good printing characteristics can therefore be obtained without using special highly smooth paper.

(Example) Hereinafter, the present invention will be explained in more detail based on Examples, where "parts" in the examples indicate "parts by weight."

Example 1 Carbon black 120 parts (Ra
ven#1035, manufactured by Columbian Carbon Japan ■) Microcrystalline wax 400 parts (Polarity: None, Hi
Mic2065, made by Nippon Seiro ■) Candelilla wax 360 parts (Polarity:
Medium, manufactured by Noda Wax ■) Dispersant 20 parts (Solsperse 17000, manufactured by ICI Japan ■) EVAFLEX45X 100 parts (ethylene-vinyl acetate copolymer, vinyl acetate content: 46 wt
%, manufactured by DuPont Mitsui Polychemical ■) Each of the above ingredients is heated and dispersed using three rolls to create a heat-melting ink! l! This was coated onto a 4.5 μm thick polyester film by gravure coating to a coating thickness of 5 μm to obtain a heat-sensitive transfer type recording material.

Example 2 Carbon black 120 parts Paraffin wax 510 parts (Polarity: None, 155°F, manufactured by Nippon Seiro ■) Carnauba wax
150 parts (Polar Two, manufactured by Noda Wax ■) EVAFLEX150 150 parts (ethylene-vinyl acetate copolymer, vinyl acetate content: 33
wt%, manufactured by DuPont Mitsui Polychemical Co., Ltd.) Petroleum resin 50 parts (Escolettes 5380, manufactured by Exxon Chemical Co., USA) Dispersant (Solsperse 17000) 20 parts The above components were prepared in the same manner as in Example 1 to prepare a thermal transfer recording material. I got it.

Example 3 Carbon black 120 parts Paraffin wax 450 parts (Polarity: None, 155°F, manufactured by Nippon Seiro) Candelilla wax
250 parts (Polar Two, manufactured by Noda Wax ■) Lanolin fatty acid 50 parts (SK
LIRO, made by Croda Japan ■) Solex CH
110 parts (ethylene-vinyl acetate copolymer, vinyl acetate content: 60 wt%, manufactured by Nippon Gosei Kagaku Kogyo ■) Dispersant (Solsperse 17000)
20 parts A heat-sensitive transfer type recording material was obtained using the above components in the same manner as in Example 1.

Example 4 The hot-melt ink prepared in Example 1 was heated to 100°C, 3000 parts by weight of an aromatic mixed solvent (Pegasol R-100, manufactured by Mobil Oil) was added thereto, stirred, and allowed to cool. A fine dispersion of this ink was obtained. Next, this fine dispersion was applied onto a 4.5 μm thick polyester film by gravure coating and dried at 85° C. to give a coating thickness of 5 μm to obtain a heat-sensitive transfer type recording material.

Comparative Example 1 Same as Example 1, EVAFLEX 45X was used as NUC cobolimer MB-850 (ethylene-vinyl acetate copolymer, vinyl acetate content: 22 wt%, Nippon Unica 14l)
A thermal transfer type recording material was obtained in the same manner as in Example 1 except that ft) was used.

Comparative Example 2 Carbon black 120 parts Paraffin wax 100 parts (Polarity: None, 155°F, manufactured by Nippon Seiro ■) Candelilla wax
470 parts (Polar Two, manufactured by Noda Wax Division) Carnauba wax 150 parts EVA
FLEX45X 100 parts Petroleum resin (Escolettes 5380) 50 parts Dispersant (Solspers 17000) 10 parts Each of the above components was added to Example 1
A thermal transfer type recording material was obtained in the same manner as above.

Comparative Example 3 Carbon black 120 parts Paraffin wax 360 parts (Polarity: None, 155°F, manufactured by Nippon Seiro ■) Microcrystalline wax 350 parts (Polarity: None, H i Mi
c2065, manufactured by Nippon Seiro ■) Solex CH 150 partial dispersant (Solspers 17000) 20 parts A hot-melt ink was prepared using the above ingredients in the same manner as in Example 1. During the temperature dispersion, the hot-melt binder and the ethylene-vinyl acetate copolymer separated, making it impossible to obtain an ink.

(Effect of the invention) Regarding the thermal transfer recording materials obtained in Examples 1 to 4 and Comparative Examples 1 to 3, the recording paper used was hamanasu paper (highly smooth paper,
Made by Honshu Paper Industries, Ltd.), high quality paper (JISP3201). Using Xerox L paper (dry copy paper, manufactured by Fuji Xerox ■), the printing characteristics of each were investigated using a word processor (JW-R55F. manufactured by Toshiba).

The results are shown in Tables 1 and 2.

*1 Dispersion state: The dispersion state of the ethylene-vinyl acetate copolymer in the ink was visually observed.

0: Good, ×: Poor dispersion state *2 Print clarity: The presence or absence of missing parts of printed characters was observed.

0: Absent, Δ: Slightly present, ×: Present *3 Print reflection density: Measured using Sakura Densitometer PDA-65 as a measuring device. The higher the value, the higher the concentration.

In addition, in Comparative Example 3, it was not possible to obtain hot-melt ink, and therefore the printing test could not be performed.

As is clear from Tables 1 and 2, the thermal transfer recording material of the present invention can print clearly not only on thermal printer paper but also on general paper (high-quality paper, dry copy paper). It is possible.

Claims (1)

[Claims] In a heat-sensitive transfer recording material comprising at least a base material and a heat-melt ink layer provided on the base material, forming a uniformly dispersed state of an ethylene-vinyl acetate copolymer in the heat-melt ink layer is provided. Features of thermal transfer recording material.