JPH0396390A - Production of thermal transfer recording paper - Google Patents

Abstract

PURPOSE:To form a satisfactory thermal transfer layer when it is applied on a substrate sheet at a room temperature by applying a thermal transfer layer having specific melting point, viscosity, and penetration on a substrate. CONSTITUTION:As a binder, a wax containing a polar group, such as vinyl and ether, and dissolving in the amount of 10wt.% or more in a solvent at 40 deg.C or lower is preferably used. As a colorant, a material selected out of arbitrary organic or inorganic pigments and dyes is selectively used by taking heat resistance, weatherability, and the like into consideration. As the physical properties of a thermal transfer layer to be formed, a melting point is 41-200 deg.C, pref. 50-90 deg.C; a viscosity at 90 deg.C is 10-3000c.p., pref. 15-2000c.p.; and a penetration is 0.1-60, pref. 0.1-30.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for producing thermal transfer recording paper.
In particular, the present invention relates to a method for producing thermal transfer recording paper that does not use a special heating means when applying an ink for forming a thermal transfer layer.

In recent years, thermal transfer recording methods have been developed as an output method for various output terminals such as computers and facsimiles due to their low noise, maintenance-free nature, simplicity of equipment, and ability to be made smaller and lighter. There is.

Thermal transfer recording paper is made by coating the surface of a substrate with good thermal conductivity with a mixture of a binder such as wax or other low-melting point substance that softens or melts when heated, and a coloring agent. Printing is performed on a recording medium by combining a recording medium and a transfer layer of a transfer paper, and printing in a pattern with a thermal head.

Conventionally, hot melt coating methods and hot lacquer coating methods in which the ink binder is dissolved in a solvent by heating at 40° C. or higher and applied are conventionally used to produce these thermal transfer recording papers.

In the hot melt coating method, since the binder itself is solid at room temperature, coating is performed by heating the binder to a temperature above its melting point.

On the other hand, the hot lacquer coating method, also called the solvent coating method, is a method in which the binder is dissolved in a solvent under heating and applied.In this method, the binder and solvent are mixed and the temperature is lower than the melting point of the binder. The binder is dissolved in a solvent and applied by heating to
In this case as well, since the wax conventionally used does not dissolve in the solvent at temperatures below 40°C, it is difficult to apply ink at normal temperatures below 40°C, and good application cannot be achieved unless some heating means is used.

Of course, it is possible to apply the above-mentioned binder by simply finely dispersing it in a solvent (so-called emulsion), but
Unevenness such as so-called "swimming" occurs on the coated surface, and uneven printing occurs during transfer, making it impossible to obtain good transfer print quality. That is, since there is no dissolved binder component,
This is because a uniform film is not formed on the surface of the substrate. Therefore, it is necessary to maintain coating suitability by dissolving the binder in a solvent using heating means during coating.

As a result of examining the suitability of various compounds as binders for inks for heat-sensitive transfer layers, the present inventor found that certain compounds are commonly used as low boiling point organic solvents at temperatures of 0°C to 40°C. The present invention has been achieved by discovering that the present invention is at least partially soluble in water and is suitable as a binder for an ink for forming a heat-sensitive transfer layer.

Such a binder has a polar group such as a vinyl group or an ether group introduced therein, and has a lOi
Waxes that dissolve in ifi% or more are preferred, and examples of waxes that dissolve in xylene include ester wax WAX E. WAXF. WAX KPS and W
AX BJ, etc., as well as partially saponified ester waxes such as WAX OP, WAX OM. Examples include WAX V and WAXGL3 (both manufactured by Hoechst).

Both of these waxes can be used at room temperature (0~40℃) compared to the solvents widely used as gravure ink solvents.
It has a solubility of 10% by weight or more and excellent binder suitability.

The above are merely specific examples, and the wax is not limited to the above examples as long as it dissolves at least 10% by weight in a solvent at 40° C. or lower.

The solvent used in the present invention is a relatively low boiling point solvent used for conventional gravure inks, and specifically, toluene, xylene, trichlene, white spirit, ethyl acetate, n-butyl acetate, isobrobanol, These waxes include n-butanol, ethylcyclohexane, etc., and those in which the wax has a solubility of 10% by weight or more are selected and used alone or as a mixture.

The coloring material used in the present invention is selected from arbitrary organic and inorganic pigments or dyes in consideration of heat resistance, weather resistance, etc., and the additive used as necessary is mineral oil. , rapeseed oil, and other oils are used.

The relative amounts of each component used as described above may be the same as those of conventionally known inks for forming a heat-sensitive transfer layer, and the method of applying the ink may be the same as that of the prior art except that continuous coating is required.

The physical properties of the heat-sensitive transfer layer formed as described above include a melting point of 41 to 200°C, preferably 50 to 90°C, and a viscosity of 10 to 3,000°C at 90°C. p. ．． Preferably 15
~2000c. p. , the penetration is from 0.1 to 60, preferably from 0 to 3o.

The base sheet supporting the heat-sensitive transfer layer may be any material as long as it has a strength that will not stretch or tear during use, and will not be deformed or partially melted by the heat of the recording thermal head. , for example, polyester,
Polypropylene, polystyrene, polycarbonate, polyimide and other plastic films, glassine paper, capacitor paper, ledger paper, Indian paper and other papers, metal foil, aluminum-paper composite sheets that are composites of the above materials, metal Examples include vapor-deposited paper and metal-deposited film.

There are no particular restrictions on the material to be transferred when recording with the above-mentioned thermal transfer recording paper, but it is preferable that the material has a highly smooth surface. For example, plastic film, paper, metal,
Wood, glass! IIi fiber etc. are used.

According to the method of the present invention as described above, when forming a heat-sensitive transfer layer, the ink used is coated onto the base sheet at room temperature, for example, 0° C. to 40° C., preferably at room temperature, without any need for heating. A satisfactory thermal transfer layer can be formed. Further, even if heating is used to adjust the viscosity of the ink or to keep the coating machine warm, it is possible to sufficiently adjust the viscosity and keep the coating machine warm at a temperature of 40° C. or lower.

Furthermore, in the heat-sensitive transfer layer formed by the method of the present invention, at least a part of the wax is dissolved in the solvent even when the ink used is at room temperature, so phenomena such as so-called "swimming" occur in the coated layer. The heat-sensitive transfer layer has a smooth surface with no coating unevenness, and therefore the prints transferred by this are also clear and have excellent resolution.

On the other hand, conventional hot lacquer coating methods and hot melt coating methods require heating means and their temperature control, and if temperature control is poor, coating may become difficult, resulting in uneven coating or uneven thickness. However, this problem is solved because the present invention does not require heating during coating.

Furthermore, with conventional coating methods that require heating during coating, it is difficult to form a multicolor heat-sensitive transfer layer by overprinting, but according to the method of the present invention, once formed, the heat-sensitive transfer layer can be softened or eroded. There is no overprinting, so overprinting is possible.
It is also easy to form multicolor patterns, striped heat-sensitive transfer layers, etc.

Furthermore, in the conventional solvent coating method, which is carried out at room temperature, the binder is not dissolved in the solvent, so so-called "swimming" occurs, resulting in an uneven heat-sensitive transfer layer, but the present invention solves this problem. There is.

Since the present invention has the above-mentioned advantages, for example, it is possible to repeatedly provide yellow, red, indigo, and ink color areas in order in the paper flow direction, and print in multiple colors with one thermal head. We can also easily provide transfer-type multicolor thermal transfer recording paper, etc.
Unlike the conventional hot-melt coating method, there is no need to heat each printing or coating unit for each color, and there are no inconveniences such as adhesion of ink once transferred to the plate.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 The following transfer ink composition was coated on a polyester film with a thickness of 12 μm using a roll coater at room temperature (25° C.) at a rate of 3 g/rr′1′ on a dry basis.
A heat-sensitive transfer layer with a smooth surface was formed.

Hoechst WAX BJ 15 parts by weight Carbon black 2 parts by weight Mineral oil
1 part by weight xylene
82 parts by weight Approximately 20 g of the above wax is dissolved in 100 g of xylene at 25°C.

When the above-mentioned thermal transfer recording paper and high-quality paper were passed through a thermal printer SP3050 manufactured by Shinko Electric Co., Ltd. for printing, black high-quality printing was obtained.

The melting point of the heat-sensitive transfer layer is 55°C, and the viscosity at 90°C is looc. p. and the penetration level was 4.

Example 2 When the following transfer ink composition was coated on a polyester film with a thickness of 12 μm using a roll coater at a dry rate of 3 g/rrr under constant dry conditions (25° C.), a thermal transfer layer with a smooth surface was obtained. was formed.

Candelilla wax 15 parts by weight Carbon black 2 parts by weight Mineral oil
1 part by weight xylene
82 parts by weight Approximately 15 g of the above wax is dissolved in 100 g of xylene at 40°C.

When the above-mentioned thermal transfer recording paper and high-quality paper were passed through a thermal printer SP3050 manufactured by Shinko Electric Co., Ltd. for printing, black high-quality printing was obtained.

The melting point of the heat-sensitive transfer layer is 80°C, and the viscosity at 90°C is 50c. p. and the penetration level was 2.

Example 3 The following transfer ink composition was applied to a 12 μm thick polyester film using a roll coater at room temperature (25°C) at a rate of 3 g/ry on dry basis. When the coating was applied at a ratio of , a heat-sensitive transfer layer having a flat surface was formed.

Lysla wax 15 parts by weight Carbon black 2 parts by weight Mineral oil
1 part by weight xylene
82 parts by weight Approximately 15 g of the above wax is dissolved in 100 g of xylene at 40°C.

When the above-mentioned thermal transfer recording paper and high-quality paper were passed through a thermal printer SP3050 manufactured by Shinko Electric Co., Ltd. for printing, black high-quality printing was obtained.

The melting point of the heat-sensitive transfer layer is 80°C, and the viscosity at 90°C is 50c. p. and the penetration level was 2.

Example 4 Transfer ink compositions of the following colors were applied to a capacitor paper with a thickness of 10 LLm at room temperature (20°C) using a gravure printing machine at a rate of 5 g/rrr on a dry basis.
Does it have a beautiful and smooth surface? A thermal transfer layer was formed.

Hoechst WAX V 30 weight @ Color material 3 parts by weight toluene
67 parts by weight The following materials were used as coloring materials.

Yellow ink; CI21090 Red ink; CI15850 Blue ink. CI74160 Black ink; Carbon black. Approximately 40 g of the above wax is dissolved in toluene at 20° C.

A printing machine equipped with the above thermal transfer recording paper and high-quality paper and equipped with a Toshiba thermal head. When passed under these conditions, a multicolor image with good print quality was obtained.

The melting point of each heat-sensitive transfer layer is 55°C, and the viscosity at 90°C is 150c. p. and ■It was ten-nin power S10・

Claims (1)

[Claims] Using an ink for forming a heat-sensitive transfer layer containing a diluent, a wax that dissolves in the diluent in an amount of at least 10% by weight, and a coloring material, an ink with a melting point of 41 to 200° C. and 90° C. is coated on a substrate at room temperature.
The viscosity at °C is 10 to 3,000 c. p. and a method for producing a heat-sensitive transfer recording paper, which comprises coating a heat-sensitive transfer layer having a penetration degree of 0.1 to 60.