JPH0480082A - Sheet-fed type composite thermal transfer sheet - Google Patents

Abstract

PURPOSE:To obtain a composite thermal transfer sheet excellent in both of the non- releasability of an end part and the adhesiveness and releasability of the whole by bonding a thermal transfer sheet wherein a hot melt ink layer is formed to one surface of a base material film and a transfer material in a releasable manner by an adhesive layer and cutting both of them on the side of the thermal transfer sheet. CONSTITUTION:In a thermal transfer sheet A, a hot melt ink layer 2 is formed on a base material film 1 and, pref., a mat layer 2 is formed between them or a slip layer 4 is formed to the rear of the base material film. The thermal transfer sheet A and a transfer material B are pref. bonded by a method wherein the transfer material is continuously bonded to the ink layer of the thermal transfer sheet while the adhesive layer is formed to the surface of said ink layer and the bonded one is taken up in a roll form and, at the time of cutting, by operating a cutter on the side of the thermal transfer sheet A, the end part of the adhesive layer C of the thermal transfer sheet A is pressed to the transfer material B and the adhesive layer C of the end part is strongly bonded to the transfer material B and, microcopically, the adhesive layer slightly penetrates in the cut surface of the transfer material B and, therefore, the adhesiveness of the end part is enhanced.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a single-fed composite thermal transfer sheet, and more specifically to a novel single-fed type composite thermal transfer sheet in which a thermal transfer sheet and a transfer material such as paper are temporarily bonded in advance. Regarding a composite thermal transfer sheet.

(Prior art and its problems) Conventionally, when printing output prints from computers or word processors using a thermal transfer method, a thermal transfer sheet with a heat-melting ink layer provided on one side of a base film has been used. .

This conventional thermal transfer sheet has a thickness of 1 mm as a base film.
Using paper such as capacitor paper or paraffin paper with a thickness of 0 to 20 μm, or plastic film such as polyester or cellophane with a thickness of 3 to 20 μm, a layer of heat-melting ink made by mixing coloring agents such as pigments and dyes with wax is applied. It is manufactured by coating.

When printing on transfer paper using these conventional thermal transfer sheets, the thermal transfer sheet is supplied from a roll wrapped with the thermal transfer sheet, while a continuous or sheet transfer material is supplied, and both are placed on a platen. In this state, a thermal head applies heat from the back side of the thermal transfer sheet to melt and transfer the ink layer to form a desired image.

However, even if you try to use these thermal transfer sheets for facsimile printers that use conventional thermal coloring paper, for example, the above-mentioned tsukushimiri printers do not have a conveyance device for the transfer material because the recording paper itself is thermally colored. This problem also applies to special printers such as large block printers.

As a method to solve the above-mentioned problems, the thermal transfer sheet and the material to be transferred are temporarily bonded in advance and wound into a roll or made into sheets, so that it can be adapted to facsimile printers, etc. Methods have been devised to simplify and downsize the device.

In the case of such a composite thermal transfer sheet, there is not much of a problem if it is wound into a roll, but if it is a sheet-fed type, the thermal transfer sheet may be damaged around the sheet, especially at the leading or trailing edge in the conveying direction. There is a problem in that the transfer material and the transfer material are likely to separate, causing various troubles when feeding the paper to the printer. Such a problem would not occur if the periphery of each sheet was bonded with an adhesive, but in reality, such an operation is completely uneconomical and cannot be adopted. Furthermore, when such adhesion is performed, the ink layer is transferred around the transfer material when the thermal transfer sheet and the transfer material are separated, resulting in contamination of the transfer material.

In addition, in the case of the above-mentioned single-fed composite track transfer sheet, the thermal transfer sheet and paper adhere firmly to each other, preventing any damage or misalignment on the heat transfer sheet, and furthermore, after the track transfer, both are easily peeled off and the transfer is completed. The ink layer is required to be accurately transferred to the paper in the area, and the ink layer is not transferred at all in the area to be transferred, so that the paper is not contaminated. On the other hand, in the case of conventional sheet-fed composite thermal transfer sheets, there has been no sheet that can fully satisfy these requirements.

Therefore, an object of the present invention is to solve the above-mentioned problems and provide a composite transfer sheet that has excellent non-peelability at the edges, excellent adhesiveness and peelability as a whole, and is free from font image resolution and scumming. It is to be.

(Means to solve problems) The above objects are achieved by the present invention as described below.

That is, the present invention provides a sheet-fed sheet formed by peelably adhering a thermal transfer sheet having a heat-fusing ink layer formed on one surface of a base film and a transfer material using an adhesive layer, and then cutting the sheet. This composite thermal transfer sheet is a single-fed composite thermal transfer sheet, characterized in that the above-mentioned cutting is performed from the thermal transfer sheet side.

(Function) By cutting from the thermal transfer sheet side, the edges of the thermal transfer sheet and the edges of the material to be transferred are bonded well, and peeling of the edges is easily prevented.

In addition, in a preferred embodiment, the adhesive layer has a specific configuration, so that the thermal transfer sheet and the paper firmly adhere to each other, preventing wrinkles or misalignment, and providing good conveyance. A sheet-fed composite thermal transfer sheet is provided, in which the ink layer is accurately transferred to the paper in the transfer area, and the transferred area is not transferred at all, so that the paper is not contaminated.

(Preferred Embodiments) Next, the present invention will be explained in more detail with reference to preferred embodiments.

A cross-sectional view of a preferred example of the single-fed composite thermal transfer sheet of the present invention is shown in FIG.

The single-fed composite thermal transfer sheet of the present invention is a single-fed composite thermal transfer sheet in which a thermal transfer sheet A and a transfer material B are releasably adhered to each other by an adhesive layer C, as shown in the figure. As schematically shown in FIG. 4, as a result of cutting from the thermal transfer sheet side, the edges of the thermal transfer sheet adhere well to the material to be transferred. Of course, this adhesion means that it is stronger than the parts other than the edges, and it is not strong enough to transfer the ink layer to the transfer material when the two are peeled off. It doesn't peel off (it doesn't peel off).

The thermal transfer sheet A has a heat-melting ink layer 2 formed on a base film 1 as shown in the figure, and in a preferred embodiment, a matte layer 3 or a base film is formed between the base film 1 and the ink layer 2. A slip layer 4 is formed on the back surface.

As the base film used in the single-fed composite thermal transfer sheet of the present invention, the same base film used in conventional thermal transfer sheets can be used as is, and other materials can also be used. There are no particular restrictions.

Specific examples of preferred base films include polyester, polypropylene, cellophane, polycarbonate, cellulose acetate, polyethylene, polyvinyl chloride,
Polystyrene, nylon, polyimide, polyvinylidene chloride, polyvinyl alcohol, fluororesin, chlorinated rubber,
Examples include plastics such as ionomers, papers such as condenser paper and paraffin paper, nonwoven fabrics, and base films made of composites of these materials.

The thickness of this base film can be changed as appropriate depending on the material so that its strength and thermal conductivity are appropriate, but the thickness is preferably, for example, 2 to 25 μm.

The heat-melting ink layer provided on the base film is composed of a colorant and a vehicle, and may further contain various additives as necessary.

As this coloring agent, it is preferable to use organic or non-containing pigments or dyes that have good properties as a recording material, such as those that have sufficient color density and do not turn brown due to light, heat, temperature, etc. .

Of course, carbon black is preferable for monochromatic black printing, and chromatic colorants such as cyan, magenta, yellow, etc. are used for multicolor printing. It is generally preferred that the amount of these colorants used is about 5 to 70% by weight in the ink layer.

The vehicle used includes wax as a main component, and mixtures of wax with drying oil, resin, mineral oil, cellulose, rubber derivatives, and the like.

Typical examples of wax include microcrystanone wax, carnauba wax, and paraffin wax. Furthermore, various products such as Fischer-Tropsch wax, various low-molecular-weight polyethylenes, wood wax, beeswax, spermaceti wax, privet wax, wool wax, shellac wax, candelilla wax, petrolactam, polyester wax, assorted waxes, fatty acid esters, fatty acid amides, etc. Wax is used. In the present invention, a thermoplastic resin having a relatively low melting point may be mixed into the wax to improve the adhesion of the ink to the transfer material.

Methods for forming a hot melt ink layer on a base film include hot melt coating, hot lacquer coating,
Examples include gravure coating, gravure reverse coating, roll coating, and many other methods. The thickness of these ink layers may be several micrometers as in the conventional case.

The transfer material B may be any sheet or film that can be thermally transferred, such as high quality paper, plain paper, synthetic paper, tracing vapor, plastic film, etc., preferably having a stiffness in the range of 10 to 100. If the stiffness is less than the above range, the stiffness of the entire sheet-fed composite thermal transfer sheet will be insufficient and the stiffness will be weak (,
The transfer sheet peels off or wrinkles due to waving, etc., causing serious problems in conveyance, and as a result, good printing is not possible. On the other hand, if the stiffness exceeds the above range, the sheet-fed composite thermal transfer sheet becomes uneconomical in terms of thickness, weight, etc.

In a more preferred embodiment, the surface smoothness of the transfer material is in the range of 10 to 500 seconds, and the basis weight of the transfer material is 3.
A range of 0 to 120 glrd gives good results.

The adhesive layer C that temporarily adheres the thermal transfer sheet A and the transfer material B can also be achieved by adjusting the adhesive strength of a conventionally known adhesive, but preferably the adhesive has a low glass transition temperature. It consists of adhesive particles, resin particles with a high glass transition temperature, and wax particles.

The glass transition temperature of the above-mentioned adhesive is preferably in the range of -90°C to -60°C, and examples of such adhesives include rubber-based adhesives, acrylic-based adhesives, and silicone-based adhesives. In addition, in terms of form, there are solvent solution type, aqueous solution type, hot melt type, aqueous or oil emulsion type, and any of them can be used in the present invention, but acrylic type is particularly suitable in the present invention. It is an aqueous emulsion type, and its particle size is about 0.2 to 10 μm, preferably 1 to 6 μm. By using such an emulsion type adhesive, the adhesive 5 of the adhesive layer maintains its particle shape as shown in the third figure.

When the above adhesive is used alone, excellent adhesion can be obtained, but the peelability of the transferred material is insufficient and uneven, and unexpected stress may be applied during manufacturing, storage, transportation, etc. before thermal transfer. If this is added, there is a problem in that the ink layer of the thermal transfer sheet is transferred to the transfer material, resulting in scumming. Furthermore, during thermal transfer, the ink layer is not easily cut, and for example, the ink layer is transferred to the periphery of the area to which heat is applied by the thermal head, resulting in poor resolution of the transferred image.

In the present invention, the above problem can be solved by adding a resin emulsion containing fine resin particles, for example, resin particles 6 with a particle diameter of about 0.01 to 0.5 μm, to the emulsion adhesive, so that the adhesiveness is within a preferable range. By adding emulsion 7 of wax similar to the one used to form the ink layer, foil breakage of the adhesive layer C is improved, and the resolution of the transferred image is improved. It was observed that there was a significant improvement in

As the above resin emulsion, for example, ethylene-
Thermoplastic resins such as vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, polyethylene, polystyrene, polypropylene, polybdenum, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer, acrylic resin, and especially acrylic emulsion are preferred. be. Such resin particles preferably have a glass transition temperature higher than that of the pressure-sensitive adhesive, for example, 60° C. or higher, and may be thermoset resin particles as the case may be.

Further, the wax emulsion is obtained by emulsifying the wax as described above by a known method, and the particle size thereof is not particularly limited, although the finer the better.

The weight ratio of the adhesive, resin particles, and wax is 3 to 5:
It is preferable that it is 1 to 2.5 and 3 to 5. If it is out of this range, the various problems described above are likely to occur, which is not preferable.

The adhesive layer C made of the above components may be provided on the surface of the transfer material B, but in this case, since the printed matter remains sticky, it is preferably provided on the surface of the ink layer 2 of the thermal transfer sheet. In this case, since the adhesive is used as an aqueous emulsion, the ink layer is not damaged, which is preferable. The emulsion coating method and drying method are not particularly limited, but
Drying is preferably carried out at a low temperature so that the emulsion particles remain.

The adhesive layer preferably has a thickness of 01 to 20 μm (01 to 5 g/rrf as solid coating amount).

The adhesion between the thermal transfer sheet A and the transferred material B is preferably carried out by continuously adhering the transferred material while forming an adhesive layer on the surface of the ink layer of the thermal transfer sheet, and then winding this up into a roll. When winding up, the material to be transferred may be placed on the outside, or the thermal transfer sheet may be placed on the outside.

The above continuous sheet cutting method is a feature of the present invention, and in the present invention, when cutting a long sheet as shown in the fourth figure,
By operating the cutter 10 from the thermal transfer sheet A side, the end of the adhesive layer C of the thermal transfer sheet A is attached to the transferred material B.
The adhesive layer C at the end adheres to the transferred material B that much more strongly, and microscopically, the adhesive layer C adheres to the transferred material B.
This results in a slight biting into the cut surface of the paper, improving the adhesion of the edges.

The above is the basic structure of the single-fed composite thermal transfer sheet of the present invention. Of course, as shown in the first figure, a slip layer 4 is provided on the back surface of the thermal transfer sheet to prevent the thermal head from adhering and to improve slipperiness. All well-known techniques in the field of thermal transfer sheets, such as making the print matte by providing a matte layer 3 between the base film and the ink layer, and making the ink layer a color other than black, are all based on this book. It can be added to the single-fed composite thermal transfer sheet of the invention.

The thermal transfer sheet of the present invention described above is set in, for example, a facsimile printer, conveyed as shown by the arrow in FIG. A desired image 9 is formed.

(Example) Next, the present invention will be explained in more detail by giving examples and comparative examples. In the text, parts or percentages are based on weight unless otherwise specified.

Example 1 A 6.0 μm thick polyethylene terephthalate film with a slip layer formed on the back side was used as a base film, and 4 glrd of the following ink composition was applied to the surface of this base film.
The ink layer was formed by coating at the following ratio.

Cup 2ヱ亙Mekkatsu Carbon Black 15 parts Ethylene/vinyl acetate copolymer 8 parts Paraffin wax 50 parts Carnauba wax
25 parts (prepared by kneading with an attritor at 120°C for 4 hours) Further, on the above ink layer, apply a temporary adhesive having the following composition by gravure coating at a rate such that the coating amount when dry is 0.5 g/g. After coating, plain paper (basis weight 64g/bo, Beck surface smoothness 1)
40sec, stiffness 50crrr/100) and nip temperature 50"C, nip pressure 500Kg),
The sheet was cut into A4 size sheets from the thermal transfer sheet side using a cutting machine to obtain a leaf-shaped composite thermal transfer sheet of the present invention.

Temporary handling■ Jodanmetsu acrylic adhesive particles aqueous dispersion (solid content 40
%, glass transition temperature -70°C5 particle size 3-10μm)
10 parts acrylic resin particles aqueous dispersion (solid content 20%, glass transition temperature 85°C
, particle size 0.2-0.5 μm) 15 parts carnauba wax aqueous dispersion (solid content 40%,
Melting point 83℃) 15 parts water
10 parts isopropanol 30 parts Examples 2 to 4 In addition, using the same dispersions as in Example 1, the composition (weight ratio) of the temporary adhesive was changed as shown in Table 2 below, and the other conditions were as in Example 1. A sheet-fed composite thermal transfer sheet of the present invention was obtained in the same manner as described above.

1--J Comparative Example 1 A sheet-fed composite thermal transfer sheet of a comparative example was obtained in the same manner as in Example 1, except that the cutting in Example 1 was carried out from the side of the transfer material.

When 20 sheets of the single-fed composite thermal transfer sheets of the Examples and Comparative Examples were handled by stacking or separating them, none of the Examples had peeled edges, but the comparison In the example, 8 sheets have peeled off at the edges, and the edges are peeled off (
It has risen.

In addition, the adhesive strength between the ink layer and paper of the sheet-fed composite thermal transfer sheets of Examples 1 to 4 was measured, and the results are shown in Table 2.

If the paper does not peel off easily even when left, it peels off easily with a fingertip after printing, and there is no background smear on the paper, mark it as ○, and if it peels off naturally or causes background smudges when left unused, mark it as ×. expressed. From these results, it was found that the adhesive force is preferably in the range of 300 to 1000 g, particularly 400 to 800 g.

In addition, the adhesive strength (g) is 25mm (width) x 50mm (length)
Cut a sample of
N-14 (manufactured by Shingengakugaku) at a tensile speed of 1800 mm/min.

(Effects) As described above, according to the present invention, by cutting from the thermal transfer sheet side, the edges of the thermal transfer sheet and the edges of the transferred material are bonded well, and peeling of the edges is easily prevented. be done.

In addition, in a preferred embodiment, the adhesive layer has a specific configuration, so that the thermal transfer sheet and the paper firmly adhere to each other, preventing wrinkles or misalignment, and providing good conveyance. A sheet-fed composite thermal transfer sheet is provided, in which the ink layer is accurately transferred to the paper in the transfer area, and the transferred area is not transferred at all, so that the paper is not contaminated.

[Brief explanation of drawings]

1 and 2 are views schematically explaining the cross section of the single-fed composite thermal transfer sheet of the present invention, FIG. 3 is a view schematically explaining the structure of the adhesive layer, and FIG. The figure is a diagram schematically showing the cutting method. A: Thermal transfer sheet B: Transferred material C: Adhesive layer D: Anti-curl layer 1, base film 3 Matte layer 5, adhesive particles 7, wax particles 9 Image: Ink layer slip layer, resin particles, thermal head, Cutter patent applicant Dai Nippon Printing Co., Ltd. Agent Patent attorney Yoshi 1) Katsuhiro and 1 other person...
6: Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] (1) In a single-fed composite thermal transfer sheet formed by bonding a thermal transfer sheet with a heat-melting ink layer formed on one side of a base film and a transfer material in a peelable manner using an adhesive layer and cutting the sheets. . A single-fed composite thermal transfer sheet, characterized in that the above-mentioned cutting is performed from the thermal transfer sheet side.