JPH0396391A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To enhance slip characteristics of a transfer ink formed on recording paper to improve wear resistance without deteriorating a printing image quality by incorporating a carbon fluoride in an adhesive layer and/or a release layer. CONSTITUTION:A carbon fluoride is incorporated in an adhesive layer and/or a release layer. The adhesive layer is formed by incorporating at least rubbers or a mixture of rubbers and waxes as a main component. In the release layer, at least waxes are contained as a main component, but a binder, a softening agent, and the like may be incorporated, as necessary. The carbon fluoride, which is a generic name of a compound of fluorine and carbon, such as tetrafluoromethane CF4 and hexafluorobenzene C6F6, is insoluble in water but soluble in many kinds of organic solvents, and generally stable physically and chemically. The content of the carbon fluoride in the adhesive layer and/or the release layer is 1-60wt.%, pref. 5-30wt.%. The content of the same in the adhesive layer is pref. 20-40wt.%. The content of the same in the release layer is pref. 5-30wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal transfer recording medium, and more particularly to a thermal transfer recording medium that has excellent abrasion resistance and provides clear images on plain paper and the like.

[Prior art]

Thermal transfer recording media have a transfer N (heat-melting ink layer) provided on a support, and the ink layer is transferred to a transfer material such as plain paper (
A thermal head or the like is brought into contact with the support from the support side to melt the ink layer, and the melted ink is transferred to the transfer target to obtain an image, and is used in transfer-type thermal printers. .

By the way, thermal transfer recording media have heretofore been known in which a transfer layer made of a heat-fusible substance such as paraffin wax and a coloring agent such as a dye or pigment is provided on a support.
Since paraffin waxes have low mechanical strength, they have the disadvantage that the abrasion resistance of transferred images is poor. In order to improve this drawback, methods such as (1) adding a thermoplastic resin to the transfer layer, and (2) making the transfer layer as thin as possible have been adopted. If the amount increases, there is a problem that the adhesive strength becomes stronger, making it difficult to transfer, and the thermal sensitivity deteriorates.In the case of (2) above, the uniformity of the transferred image deteriorates and the image density decreases. There's a problem.

Furthermore, in order to prevent the adhesive force from becoming strong even if the resin content is large, water or solvent-dispersed particle inks have been considered, but if the particle nature is too strong, there is a problem that thermal sensitivity deteriorates.

[Problem to be solved by the invention]

The present invention solves the above-mentioned problems, and also prevents the ink from peeling off from the recording paper when the ink transferred to the recording paper (including the receiving layer of the recording paper) is rubbed by some external force. To provide a thermal transfer recording medium which eliminates the inconvenience that the attached ink moves and makes the transferred image difficult to read, and which improves the abrasion resistance of the transferred ink.

[Means to solve the problem]

In the present invention, a release layer mainly composed of wax is provided on a support directly or via an adhesive layer mainly composed of rubber, and a colorant, a thermoplastic resin, and a wax are applied on the peeling layer. In a thermal transfer recording medium which is provided with an ink layer as a main component and further provided with an overcoat layer containing a wax as a main component, if necessary, fluoride is added to the adhesive layer and/or the release layer. It is characterized by containing carbon.

Incidentally, as a result of various studies in order to achieve the above object, the inventor of the present invention discovered that by incorporating fluorocarbon into the above-mentioned release layer, fluorocarbon can be added to the upper part of the ink image transferred to the recording paper. Therefore, it was confirmed that the surface of the transferred image has good slipperiness and that even if the image is rubbed by any external force, the ink does not peel off or shift. The present invention has been made based on this.

The thermal transfer recording medium of the present invention will be explained in more detail below.

Examples of the support include relatively heat-resistant plastic films such as polyester, polycarbonate, polyacetylcellulose, nylon, and polyimide, as well as glassine paper, condenser paper, metal foil, and composites of the above materials. be able to. Examples of the composite include an aluminum/paper composite, metallized paper, or metallized plastic film.

The thickness of the support is preferably about 2 to 15 microns when considering a thermal head as a heat source during thermal transfer, but when using a heat source that can selectively heat the thermal transferable ink layer, such as a laser beam, for example. There are no particular restrictions. In addition, when using a thermal head, a heat-resistant protective layer made of silicone resin, fluororesin, polyimide resin, epoxy resin, phenol resin, melamine resin, nitrocellulose, etc. should be provided on the surface of the support that comes into contact with the thermal head. This makes it possible to improve the heat resistance of the support, or to use a support material that could not be used conventionally.

The adhesive layer is provided as necessary, and is made of at least rubber or a mixture of rubber and wax as a main component.

Examples of the rubbers used here include imprene rubber, butadiene rubber, styrene butadiene rubber, nitrile rubber, ethylene propylene rubber, butyl rubber, silicone rubber, fluorine rubber, and urethane rubber. Particularly preferred among these are isoprene rubber, butadiene rubber, ethylene propylene rubber, butyl rubber, and nitrile rubber.

The melting point is preferably 60°C to 200°C. Examples of natural waxes include beeswax, spermaceti wax, candelilla wax, carnauba wax, rice bran wax, montan wax, ozokerite, etc., and petroleum-based waxes such as paraffin wax, microcrystalline wax, etc. Examples include various modified waxes, hydrogenated waxes, long-chain fatty acids, and the like. The melting point or conversion point is preferably about 60 to 90°C.

The thickness of the adhesive layer is 0.1 to 3 μs, preferably 0.3 to 1
．． 0 μm, and when the adhesive layer is used in combination with rubber and wax, the ratio of rubber/wax is 3/
1 to 1/3< leprosy is appropriate.

The release layer is a layer that makes it easier to separate the ink layer from the support of the thermal transfer recording medium when the thermal transfer recording medium and the transfer target are peeled off after printing with a thermal head, etc., and contains at least wax as a main component. However, if necessary, binder,
A softener or the like may be contained.

The thickness of the release layer is 0.5 to 4 pm, preferably 1 to 3 pm.

In the present invention, carbon fluoride is contained in these adhesive layers and/or release layers.

Carbon fluoride is a general term for compounds of fluorine and carbon, including tetrafluoromethane CF4, hexafluorobenzene C. F. They are insoluble in water but soluble in many organic solvents, and are generally physically and chemically stable.

The content of fluorocarbon adhesive layer and/or release layer is 1
-60 weight 2, preferably about 5-30 weight z. The content in the adhesive layer is preferably 20 to 40% by weight2, and the content in the release layer is preferably 5 to 30% by weight2. If the weight is less than 1 weight 2, the transferred ink will have poor slipperiness and will deform due to external force. , releasability between the ink layer and the base film).

The ink layer is a heat-melting layer similar to that of conventional thermal transfer recording media, and contains colorants, waxes, and resins as main components.

The colorant is appropriately selected from conventionally known dyes and pigments.

As the wax, the same waxes as those mentioned in the explanation of the adhesive layer are used.

Resins (thermoplastic resins) include polyamide-based, polyester-based, polyurethane-based, vinyl chloride-based, cellulose-based, petroleum-based, styrene-based, butyral-based, and phenol-based resins, as well as ethylene-vinyl acetate copolymers and Examples include ethylene-acrylic resins.

The ratio of each material is colorant/wax/resin=
5-50/30-9075-50 is suitable. In addition to these, known plasticizers and oils such as fatty acid esters, glycol esters, phosphoric acid esters, and eboxidized linseed oil may be added to the ink layer as long as they are in small amounts (30% by weight or less).

The ink layer is applied as a hot melt or dissolved or dispersed in a solvent, and is then dried to form a shape.

The thickness is 0.5 to 5 μm, preferably 1 to 3 μm.

The overcoat layer, which is provided as necessary, is a layer to prevent scumming and improve printing quality on low-smoothness paper, and contains wax as a main component, and if necessary, adhesive,
It contains a viscosity modifier and the like.

The thickness of the overcoat layer is about 0.1 to 31 JrM, preferably about 0.5 to 2μ.

In order to actually produce the thermal transfer recording medium of the present invention, each of the layers described above may be sequentially formed on a support film by a hot melt method, a solvent dispersion coating method, an aqueous emulsion coating method, or the like.

〔Example〕

Next, examples and comparative examples will be shown. All parts herein are by weight.

Example 1 (Adhesive layer) Isoprene rubber 6 parts Lunauba wax 2 parts Fluorocarbon (manufactured by M Glass Co., Ltd. L-171.) 2 parts Toluene
90 parts (release layer) Carnauba wax 5 parts Paraffin wax 5 parts Toluene
90 parts (ink layer) Polyethylene wax 11 parts Polyester resin 11 parts Carbon black 3 parts Toluene
85 parts (Overcoat M) Carnauba wax 8 parts Styrene resin 2 parts Toluene
90 parts After dispersing a certain amount of the above mixture in a ball mill for 12 hours, about 6 μm
A thermal transfer recording medium was prepared by sequentially applying and drying the mixture onto a thick polyester film using a wire bar. The thickness of each layer was approximately 0.5 pm for the adhesive layer, approximately 2 μm for the release layer, approximately 2 μm for the ink layer, and approximately 11 μm for the overcoat layer.

Example 2 Instead of adding 2 parts of fluorocarbon to the adhesive layer, the release layer forming solution was mixed with carnauba wax, 4 parts paraffin wax, and 4 parts fluorocarbon (
M Glass L-171) 2 parts toluene
Other than 90 copies,
A thermal transfer recording medium was produced in exactly the same manner as in Example 1.

Example 3 A thermal transfer recording medium was produced in exactly the same manner as in Example 2, except that the shapes of the adhesive layer and overcoat layer were omitted.

Comparative Example 1 A thermal transfer recording medium was produced in exactly the same manner as in Example 1 except that fluorocarbon was not added to the adhesive layer.

Comparative Example 2 A thermal transfer recording medium was produced in exactly the same manner as in Example 2 except that fluorocarbon was not added to the release layer.

Comparative Example 3 Peeling layer type solution was made of carnauba wax, 4 parts paraffin wax, and 4 parts silica.
2 parts toluene
Example 3 except that 90 parts were used.
A thermal transfer recording medium was made in exactly the same manner as described above.

Using these six types of thermal transfer recording media, the overcoat layer or ink layer was brought into close contact with the surface of high-quality paper, and printing was performed by applying an energy of 0.5 mJ/dat using a commercially available thermal transfer printer. Furthermore, in order to test the abrasion resistance of the printed image, a lab tester (manufactured by Toyo Seiki Co., Ltd.) was used to test the abrasion resistance (60% Rl {Te 20℃,
50° C.) was tested.

The results were as shown in Table-1. In addition, all evaluations in Table 1 (evaluation by O, Δ, and ×) are based on visual observation.

Table-1 Note) ○ is good △ is normal × means bad.

〔Effect of the invention〕

As is clear from the description of the examples, the adhesive layer and/or peeling ii! By using a thermal transfer recording medium containing an appropriate amount of carbon fluoride in the layer, the slippage of the transfer ink on the recording paper becomes better, and the abrasion resistance is improved without degrading the printed image. can do.

Claims (1)

[Claims] (1) A release layer mainly composed of wax is provided on the support, either directly or via an adhesive layer mainly composed of rubber, and a colorant, thermoplastic resin, and wax are mainly coated on the peeling layer. In a thermal transfer recording medium provided with an ink layer as a component, and further provided with an overcoat layer containing wax as a main component, if necessary, carbon fluoride is provided in the adhesive layer and/or release layer. A thermal transfer recording medium characterized by containing.