JP2516614B2 - Recording material for energized thermal transfer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a recording material for electric heat-sensitive transfer.

More specifically, the present invention relates to a recording material for electrically conductive heat-transfer which is useful for print recording such as recording of noiseless typewriter, output of computer or copying transmission.

[Conventional technology]

In recent years, thermal transfer recording has become a non-impact, noiseless, low cost, small size and lightweight computer,
In the field of facsimiles and the like, attention is paid to the method of conducting heat-sensitive transfer with a conducting head, which is the most promising method as a promising hard copy.

Generally, the energization thermal transfer recording method causes an energization head consisting of an energization recording electrode and a return electrode to press-contact with an energization thermal transfer recording material consisting of a resistance layer, a conductive layer, an ink layer and the like to energize the resistance layer to generate heat. To heat up. The heat is transferred to the ink layer by the heat, the temperature of the ink layer is raised, and the ink layer is melted and fluidized to be transferred and recorded on the recording material.

In such an energization thermal transfer recording method, since the resistance layer generates heat by energization, it is important to properly set the resistance value of the resistance layer. Conventionally, conductive carbon black is dispersed in a polycarbonate resin to form the resistance layer. There is also known a method for forming the resistance layer (described in JP-A-54-87234), a method for forming a resistance layer by dispersing carbon black in a polyamide resin such as nylon-6 (described in JP-A-59-120494), and the like. Has been.

[Problems to be solved by the invention]

However, the resistance layer formed by the above-mentioned conventional method has insufficient heat resistance, and is damaged by heat under the condition of producing a sufficient dot density (high applied voltage-current), perforation of the film, cutting, In addition, there are problems such as causing unevenness in dot quality.

[Means for solving problems]

Therefore, as a result of intensive studies to solve such problems, the present inventors have used a resistance layer in which carbon black is blended with a specific polyester carbonate resin to obtain a sufficient dot density (high applied voltage-current). )
The inventors have found that the present invention is not damaged by heat even when, and reached the present invention.

That is, the gist of the present invention is to obtain a recording by heat-generating the resistance layer by energization to thermally transfer the ink layer to the recording paper, wherein the resistance layer is 10 to 60% by weight of carbon black and A recording material for electric heat-sensitive transfer characterized by comprising 90 to 40% by weight of a polyester carbonate resin comprising repeating units represented by the general formulas (I) and (II).

(In the above formula, R ₁ and R ₂ are each independently -S -, - SO -, - SO 2 -, - O- or Represents a divalent group represented by (R ₃ and R ₄ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group). Also Either one or a mixture thereof).

 The present invention will be described in detail below.

As the carbon black of the present invention, any of the ordinary carbon blacks, including conductive carbon black, can be used alone or in combination of two or more, and particularly preferably, the mercury porosimeter method is used. Pore volume is less than 2.5cc / g measured by mercury, the maximum peak position of pore distribution measured by mercury porosimetry method is more than 200Å, and DBP (dibutyl phthalate) absorption is 20 ~ 250ml. / 100g of carbon black.

Polyester carbonate resin used in the present invention,
It is a copolymer having an ester bond and a carbonate bond in the molecule and is obtained by reacting a bisphenol compound represented by the following general formula (III), an aromatic dicarboxylic acid or its derivative, and phosgene according to a conventional method.

Examples of such bisphenol compounds include bis (4
-Hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, bis (4-hydroxy) Phenyl) diphenylmethane, bis (4-hydroxyphenyl) phenylmethane, 1,1-bis (4-hydroxyphenyl) -1-
Phenylethane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide, 4,
4'-dihydroxydiphenyl sulfone and the like can be mentioned.

Isophthalic acid and terephthalic acid are suitable as the aromatic dicarboxylic acid, and depending on the polymerization method, an acid chloride or phenyl ester which is a derivative thereof is used.

The polyester carbonate resin used in the present invention is composed of the repeating units represented by the general formula (I) and the general formula (II), and the constitutional weight ratio thereof is preferably 90:10 to 1
It is 0:90, more preferably 80:20 to 20:80.

When these resins are used in the present invention, the reduced viscosity (η _sp / C) thereof is suitably 0.25 to 0.75 measured at 20 ° C. in 0.6 g / dl of methylene chloride.

The mixing ratio of the carbon black and the polyester carbonate resin is 10:90 to 60:40, preferably 2 by weight.
It is from 0:80 to 50:50.

That is, if the carbon black is 10% by weight or less, the electrical conductivity of the resistance layer is too small, and if it is 60% by weight or more, the strength of the film is insufficient, which is not suitable.

If necessary, an appropriate amount of additives such as a dispersant, an oil lubricant and a softening agent may be blended.

The resistance layer of the present invention has a thickness of 30 μm or less, preferably 20 μm, which is obtained by uniformly mixing the carbon black and the polyester carbonate resin and then subjecting them to melt extrusion or solution casting.
It can be obtained by forming the following film.

The melt extrusion method is not particularly limited as long as it is generally known, and specifically, a method of extruding from a T-type die to form a flat film (T die method), an extruding from a ring-shaped circular die. At the same time, a method of blowing compressed gas to form a tubular film (inflation method), a stretching method of stretching the film obtained by these methods, and the like can be mentioned.

Further, the solution casting method, carbon black is put in an organic solvent system in which a resin is dissolved, sufficiently mixed with a ball mill or the like, and a paint in which carbon black is dispersed is used as a reverse roll, a gravure roll, a doctor blade, or the like, It is applied on a support such as a polyester film or a glass plate, the solvent is evaporated to dryness, and then peeled from the support to obtain a conductive film.

The conductive film of the present invention obtained as described above is used as a resistance layer of a recording material for electric heat-sensitive transfer, which is formed by laminating a conductive layer and an ink layer, or a conductive layer, a peeling layer and an ink layer. For example, in the case of producing a recording material for current-carrying thermal transfer comprising three layers of a resistance layer, a conductive layer and an ink layer, after forming the resistance layer made of the conductive film obtained by the above method, it is used as a conductive layer. A thin film of a good conductive material such as aluminum is formed on the resistance layer by a vapor deposition method or the like. Then, the ink layer is coated on the conductive layer on the side opposite to the resistance layer by a hot melt method or a solution method.

The ink layer is not particularly limited as long as it is used in a known heat-sensitive transfer recording material, and its component constitution is, for example, paraffin wax, modified wax,
About 60% by weight of wax such as carnauba wax, about 20% by weight of colorant pigment or dye, and about 20% by weight of resin are preferable.

Each layer is formed as described above, and the thickness of each layer is 1 to 10 μm; 0.01 to 0.2 μm;
μm or less, preferably 2 to 5 μm; 0.05 to 0.1 μm; 20 μ
m or less.

Note that a release layer such as polyketone may be provided between the ink layer and the conductive layer in order to improve the separation between the ink layer and the conductive layer.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples as long as the gist thereof is not exceeded.

Example 1 The following polyester carbonate resin crushed to about 100 μm (“C250A” manufactured by Mitsubishi Kasei Corporation, glass transition temperature 18)
2 ° C) ^{* 1} 1.140 kg and the following carbon black "# 10B" (manufactured by Mitsubishi Kasei Co., Ltd.) ^{* 2} 0.860 kg were charged into a Henschel mixer with an internal volume of about 9, and mixed at room temperature at 2,500 rpm for 1 minute.

And is composed of repeating units of 50:50.

* 2 Pore volume: 0.75cc / g Maximum peak position of pore distribution: 600Å DBP absorption: 86ml / 100g After leaving the resulting mixture in a vacuum dryer heated to 140 ° C for 12 hours The mixture was kneaded with a twin-screw kneader (30φ, L / D = 25) to obtain a chip-shaped compound.

This compound was dried in a vacuum dryer at 140 ° C for 24 hours, then a single-screw extruder with T-die (D = 30φ, L / D = 2
2), die temperature 300 ℃, lip clearance 0.
A film having a thickness of 45 mm, an extrusion rate of 2 kg / H, and a take-up speed of 12 m / min was obtained to have a thickness of 15 μm.

Comparative Example 1 A conductive film was produced in the same manner as in Example 1 except that the resin of Example 1 was changed to nylon-6 (“Novamid 1030CA” manufactured by Mitsubishi Kasei Co., Ltd., glass transition temperature 70 ° C.).

Comparative Example 2 Conductivity was the same as in Example 1 except that the resin of Example 1 was changed to a polycarbonate resin using bisphenol A as a raw material (“Novarex 7030A” manufactured by Mitsubishi Kasei Kogyo Co., Ltd., glass transition temperature 150 ° C.). A film was produced.

Application Example Aluminum was vapor-deposited on the film obtained in Example 1 to a thickness of 0.08 μm using a commercially available vacuum vapor deposition apparatus.

Then, an ink having the following composition was applied on the vapor deposition surface to a thickness of 4 μm.

(Ink composition and preparation method) Carbon black ...... 15 parts (Mitsubishi Chemical's "MA-8") Paraffin wax ...... 25 parts Oxide wax ...... 40 parts Ethylene / vinyl acetate copolymer ...... 20 parts (Hoechst TM-PEV-720 manufactured by the company) The above mixture was premixed with a mixer and then kneaded 5 times with a 6-inch three-roll mill. 3μ in this ink
There were no carbon black aggregates of m or more.

Applied voltage 12V, pulse frequency 100H
As a result of printing on plain paper under the conditions of z, pulse width 2 me, and paper feed speed 16 mm / S, clear and unblurred characters were recorded.

A printing test was conducted on the films obtained in Comparative Examples 1 and 2 with the same formulation. When the film was perforated, the head was also soiled, the characters obtained were gradually thinned, and finally the characters were not transferred. It was

〔The invention's effect〕

As described above, the recording material for electric heat-sensitive transfer obtained by the present invention is excellent in heat resistance, can be used under the condition of producing a sufficient dot density, and has high commercial value.

Claims (2)

(57) [Claims] 1. A current-sensitive thermal transfer recording method in which recording is performed by heat-generating an ink layer on a recording paper by heating the resistance layer by energization, and the resistance layer is carbon black 10.
To 60% by weight and 90 to 40% by weight of a polyester carbonate resin composed of repeating units represented by the following general formulas (I) and (II). (In the above formula, R ₁ and R ₂ are each independently -S -, - SO -, - SO 2 -, - O-, or Represents a divalent group represented by. (R ₃ and R ₄ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group). Also, Indicates either one or a mixture thereof. ). ) 2. The maximum peak positions of the pore volume and pore distribution of the carbon black measured by the mercury porosimeter method are 2.5 cc / g or less and 200 Å or more, respectively,
And the DBP (dibutyl phthalate) absorption is 20 ~ 250ml / 100
The recording material for electrically conductive heat transfer according to claim 1, wherein the recording material is g.