JP2000153672A - Heat-transfer sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-transfer sheet wherein the abrasion-resistance of a printed matter does not deteriorate even if a wax having a large penetration and a low melting point is used, a peeling sound when a thermal fusion ink layer of the heat transfer sheet is peeled from a base material film at the time of a printing, does not become large, both of the printing quality and the abrasion-resistance of a printed matter are excellent, and which is favorable from the aspects of the workability and the cost in the manufacture. SOLUTION: In this heat-transfer sheet wherein on one surface of a base material film, at least a thermal fusion ink layer is provided, the thermal fusion ink layer is constituted of a wax, a resin and a coloring agent, and the solubility parameter of the resin is 9 or higher, and the content of the resin is set at 20 wt.% or higher to the total solid component of the thermal fusion ink layer. By this constitution, when the resin is used by a rate of 20 wt.% or higher, the compatibility of the wax and the resin in the thermal fusion ink layer is properly unfavorable, and the tackiness of the resin in the thermal fusion ink layer at the time of a printing is reduced, and a peeling sound when the ink layer is peeled from the base material film at the time of a printing can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer sheet, and more particularly, to a printed material having good print quality and excellent abrasion resistance. The present invention relates to a thermal transfer sheet in which a peeling sound peeling from a material film does not increase.

[0002]

2. Description of the Related Art Conventionally, a thermal transfer sheet is used in which a hot-melt ink layer in which a coloring agent such as a pigment or a dye is dispersed in a binder such as a hot-melt wax or resin is carried on a base sheet such as a plastic film. And applying energy according to the image information by a heating device such as a thermal head,
2. Description of the Related Art A melt transfer method for transferring a colorant together with a binder onto an image receiving sheet such as paper or a plastic sheet is known. The printed image formed by this fusion transfer method is
It has high density and excellent sharpness, and is suitable for recording binary images such as characters and line drawings. Also, by using a thermal transfer sheet having a hot-melt ink layer of yellow, magenta, cyan, black, etc., by superposing and printing each hot-melt ink layer on an image receiving sheet, multicolor or full-color images can be formed by subtractive color mixing. Formation is also possible.

[0003] In the case of printing a bar code or the like having strict specifications for line width, line interval, and length by a melt transfer method, the thermal transfer sheet has a film-cutting property of a hot-melt ink layer. Good and sharp printing is required. Further, the printed matter is required to have abrasion resistance in order to make the reading by the bar code reader accurate and to prevent the printed portion from being rubbed and stained by handling the printed matter. On the other hand, many types of thermal-melt ink layers of the thermal transfer sheet are mainly made of a resin such as an acrylic resin or a vinyl acetate resin.

[0004]

However, in the conventional thermal transfer sheet, the hot melt ink layer can be easily coated with a hot melt by using a wax having a large penetration and a low melting point such as paraffin wax. In general, the transfer sensitivity in printing is increased. This thermal transfer sheet has a problem in that the printed matter does not have good scratch resistance, and when reading a printed portion such as a bar code, a reading defect occurs. In addition, in the case where the hot-melt ink layer of the thermal transfer sheet is mainly made of wax having a small penetration such as carnauba wax, the scratch resistance of printed matter is improved, but the wax having a small penetration has a high melting point. However, there is a disadvantage that the printing transfer sensitivity is low. In addition, natural products such as carnauba wax have a problem that the production amount is unstable and the cost is high.

[0005] In order to improve the abrasion resistance of printed matter, it is common to add a resin to the hot-melt ink layer of the thermal transfer sheet. There is a problem that becomes large.
Therefore, the present invention has been made in view of the above circumstances, even if a wax having a high penetration and a low melting point is used, the abrasion resistance of the printed matter is not deteriorated, and at the time of printing. A thermal transfer sheet that is excellent in both print quality and scratch resistance of printed matter, and has good workability in manufacturing and cost, without making the sound of the hot-melt ink layer of the thermal transfer sheet peeling off from the base film large. It is intended to provide.

[0006]

Means for Solving the Problems To achieve the above object, the present invention provides a thermal transfer sheet having at least one hot-melt ink layer provided on one surface of a base film, wherein the hot-melt ink layer is made of wax, The resin is characterized by having a SP value of 9 or more and a resin content of 20% by weight or more based on the total solid content of the hot-melt ink layer. It is preferable that the wax contains a wax having a penetration of 4 or more as a main component.
The softening point of the resin is preferably in the range of 120 to 140 ° C.

The operation of the present invention is as follows. The heat transfer sheet of the present invention is a heat transfer sheet provided with at least a hot-melt ink layer on one surface of a base film,
The hot-melt ink layer is composed of a wax, a resin, and a colorant, the SP value of the resin is 9 or more, and the content of the resin is 20% by weight or more based on the total solid content of the hot-melt ink layer. . As a result, when the above resin is used in a proportion of 20% by weight or more, the wax and the resin in the hot melt ink layer are appropriately incompatible with each other, so that the tack of the resin in the hot melt ink layer at the time of printing is reduced. In addition, the peeling sound of the ink layer peeling from the base film during printing can be suppressed. Also,
The above-mentioned hot-melt ink layer contains 20 or more resins having an SP value of 9 or more.
Since the hard resin is contained in the soft wax because it is contained by weight% or more, the scratch resistance of the printed matter is improved.

[0008]

Next, embodiments of the present invention will be described in detail. The basic form of the thermal transfer sheet of the present invention is a configuration in which at least a hot-melt ink layer is provided on one surface of a base film, but a release layer is provided between the hot-melt ink layer and the base film. Alternatively, an adhesive layer can be provided on the hot-melt ink layer, and a heat-resistant layer can be provided on the other surface of the base film.

(Base Film) As the base film used in the present invention, the same base film as used in the conventional thermal transfer sheet can be used as it is, and other base films can be used. There is no particular limitation. Specific examples of preferred base film include, for example, polyester, polypropylene, cellophane, polycarbonate, cellulose acetate, polyethylene, polyvinyl chloride, polystyrene, nylon, polyimide, polyvinylidene chloride, polyvinyl alcohol, fluororesin, chlorinated rubber, ionomer, etc. Plastic films, condenser paper, paper such as paraffin paper, non-woven fabric, etc.
Further, a substrate film in which these are combined may be used. A particularly preferred substrate film is a polyethylene terephthalate film. The thickness of the substrate film can be appropriately changed depending on the material so that the strength and the thermal conductivity are appropriate, but the thickness is preferably, for example, 2 to 25 μm.

(Release Layer) The release layer formed on one surface of the base film is melted at the time of thermal transfer to improve the releasability of the hot-melt ink layer. It is transferred together with the hot-melt ink layer, giving the protective layer of the hot-melt ink layer, especially good slipperiness to the transferred image,
It functions to improve the scratch resistance of the transferred image. In the present invention, first, a release layer is formed on one surface of the base film. For this release layer, for example, acrylic resin, silicone resin, fluorine resin, various resins modified with silicone or fluorine, which are excellent in release property, can be used, but wax is preferable.

As such a wax, various kinds of waxes which melt during printing and exhibit releasability are preferred. Suitable waxes include, for example, microcrystalline wax, carnauba wax, paraffin wax, Fischer-Tropsch wax, various low molecular weight polyethylenes, wood wax, beeswax, whale wax, Ibota wax,
Wool wax, shellac wax, candelilla wax,
Petrolactam, partially modified wax, fatty acid ester,
Various waxes such as fatty acid amides are included. Particularly preferred waxes are microcrystalline wax and carnauba wax which have relatively high melting points and are hardly soluble in solvents. The release layer is a thin layer, for example, 0.1% in a dry state so as not to lower the sensitivity of the thermal transfer sheet.
The thickness is preferably about 2 μm.

(Hot-melt ink layer) The hot-melt ink layer formed on the base film is composed of wax, resin, and colorant, and the resin has an SP value of 9 or more, and the SP value of the resin is 9 or more. The upper limit is a value at which the wax and the terpene phenol are not compatible with each other, and is about 11. The content of the resin is 20% by weight or more with respect to the total solid content of the hot-melt ink layer, and the upper limit is about 60% by weight because when the proportion of the wax is small, the printing tends to be inferior. More preferably, it is easy to apply in a hot melt state.
0% by weight or less. The resin having an SP value of 9 or more, which is a constituent resin of the hot-melt ink layer, will be described below.

[0013] Specific examples of the resin having an SP value of 9 or more include terpene phenol compounds. Terpene phenol compounds are obtained by synthesizing terpenes and phenols, and α-pinene, β
-Pinene, dipentene, [Delta] ^3- carene and the like, and two or more of these can be used in combination. Phenols include phenol, cresol, xylenol, propylphenol, nonylphenol, mitoxyphenol, bromophenol, hydroquinone,
Examples thereof include resorcin, dihydroxynaphthol, naphthol, methylnaphthol and the like, and two or more of these can be used in combination.

Using the above terpenes and phenols, a terpene phenol compound can be produced, for example, by a solution polymerization method. As a catalyst, a Friedel-Crafts catalyst such as aluminum chloride and boron fluoride, acid clay, sulfuric acid, An acidic catalyst such as phosphoric acid or an ion exchange resin is used. Examples of the solvent include aromatic hydrocarbon solvents such as toluene, xylene, and benzene. Using these, 20 ℃
It can be synthesized at a reaction temperature of ２００200 ° C. As the alicyclic petroleum resin such as the above terpene phenol compound, those having a softening point in the range of 120 to 140 ° C. are preferably used, whereby the wax and the resin in the hot melt ink layer are completely compatible. Therefore, the tackiness of the resin in the hot-melt ink layer at the time of printing is reduced, and the peeling sound of the ink layer peeling from the base film at the time of printing can be suppressed.
Further, since the hard resin is dispersed in the soft wax, the scratch resistance of the printed matter is improved.

As the binder resin, in addition to the above resins, medium density polyethylene, high density polyethylene,
Polypropylene resin, polyester resin, polyamide resin, ionomer resin, ethylene-acrylate resin,
Thermoplastic resins having a relatively low softening point such as styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, and polystyrene resin can be used. As the wax used in the hot melt ink layer, as the wax, for example,
Microcrystalline wax, carnauba wax, paraffin wax, Fischer-Tropsch wax,
Various low molecular weight polyethylenes, various waxes such as wood wax, beeswax, spermaceti, Ibota wax, wool wax, shellac wax, candelilla wax, petrolactam, polyester wax, partially modified wax, fatty acid ester, fatty acid amide and the like can be mentioned.

Of the above-mentioned waxes, it is preferable to use a wax having a penetration of 4 or more and a low melting point as a main component, to apply hot melt as a hot-melt ink, and to enhance the sensitivity of printing. As the wax having a penetration of 4 or more, specifically, the above various waxes can be used as long as the penetration is 4 or more, such as paraffin wax and microcrystalline wax. Generally, a wax having a penetration of 10 or more is distributed as a general-purpose product and can be obtained at a low price. Therefore, it is more preferable to use a wax having a penetration of 10 or more. Further, the upper limit of the penetration of the wax is about 12. The wax content in the hot-melt ink layer is from 40 to 40% of the total solid content of the hot-melt ink layer.
It is about 70% by weight. In the present invention, as the colorant, each colorant such as yellow, magenta, cyan, black, and white can be appropriately selected from conventionally known dyes and pigments. In the coating liquid of the hot melt ink layer of the present invention, the wax, the resin and the coloring agent, and if necessary, a plasticizer,
Auxiliary agents such as surfactants, lubricants and flow control agents can also be added.

The hot-melt ink layer is formed by applying a coating liquid for forming a hot-melt ink layer mixed with the above-mentioned materials to a conventionally known coating method, for example, hot melt coating, hot lacquer coating, gravure direct coating, gravure reverse coating, It can be performed by a method such as knife coating, air coating, and roll coating. In the thermal transfer sheet of the present invention,
It is desirable to use a wax having a penetration of 4 or more and a low melting point as the wax in the hot-melt ink layer, and the hot-melt ink layer is preferably formed by hot melt coating. The thickness of the hot-melt ink layer is 0.5 to
About 6 μm is preferable. If it is less than 0.5 μm, sufficient coloring properties cannot be obtained, and if it exceeds 6 μm, a large amount of printing energy is required, which is not preferable.

(Adhesive Layer) The thermal transfer sheet of the present invention can be provided with an adhesive layer on the hot-melt ink layer. The adhesive layer can improve the adhesiveness between the image receiving sheet and the transferred hot-melt ink layer. The adhesive layer is mainly composed of a thermoplastic resin which is softened by heating with a thermal head, laser or the like to exhibit adhesiveness, and waxes are used to prevent blocking when the obtained thermal transfer sheet is wound into a roll. An anti-blocking agent such as amides, esters and salts of higher fatty acids, powders of fluororesins and inorganic substances can be added.

As the thermoplastic resin, for example, ethylene-
Vinyl acetate copolymer (EVA), ethylene-acrylate copolymer (EEA), polyester resin, polyethylene, polystyrene, polypropylene, polybutene, petroleum resin, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol , Vinylidene chloride resin, methacrylic resin, polyamide, polycarbonate,
Polyvinyl formal, polyvinyl butyral, acetylcellulose, nitrocellulose, polyvinyl acetate,
Examples thereof include polyisobutylene, ethyl cellulose, and polyacetal, and particularly those having a relatively low softening point conventionally used as a heat-sensitive adhesive, for example, a softening point of 50 to 150 ° C.

The adhesive layer is formed by hot-melt coating of the above-mentioned thermoplastic resin and additives or a coating solution for forming an adhesive layer in which an appropriate organic solvent or water is dissolved or dispersed in a known hot-melt coat, Lacquer coat, gravure direct coat, gravure reverse coat, knife coat, air coat, roll coat, etc.
A thickness of 0.05 to 5 μm is provided in a dry state.
When the thickness of the dried coating film is less than 0.05 μm, the adhesiveness between the image receiving sheet and the hot-melt ink layer is poor, resulting in poor transfer during printing. On the other hand, if the thickness exceeds 5 μm, the transfer sensitivity at the time of printing decreases, and satisfactory printing quality cannot be obtained.

(Heat-Resistant Layer) In the present invention, when a heat-sensitive material is used as the base film, a heat-resistant layer for improving the slipperiness of the thermal head and preventing sticking is provided on the surface in contact with the thermal head. It is preferred to provide a layer. The heat-resistant layer has a heat-resistant resin and a substance acting as a heat releasing agent or a lubricant as basic components. By providing such a heat-resistant layer, thermal printing can be performed without sticking even on a thermal transfer sheet based on a plastic film that is weak to heat, and the plastic film is difficult to cut and easy to process. You can take advantage of such advantages.

The heat-resistant layer comprises a binder resin, a slip agent,
It is suitably used and formed by adding a surfactant, inorganic particles, organic particles, a pigment and the like. Binder resin used for the heat-resistant layer, for example, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, cellulose acetate butyrate, cellulose resin such as nitrified cotton, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal And vinyl resins such as polyvinylpyrrolidone, acrylic resin, polyacrylamide, acrylonitrile-styrene copolymer, polyester resin, polyurethane resin, silicone-modified or fluorine-modified urethane resin.

Among these, those having several reactive groups, for example, those having a hydroxyl group, are used.
It is preferable to use a crosslinked resin in combination with a polyisocyanate or the like. The means for forming the heat-resistant layer may be prepared by dissolving or dispersing a material obtained by adding a slipping agent, a surfactant, inorganic particles, organic particles, a pigment, etc. to a binder resin in an appropriate solvent as described above, Is prepared, and the coating liquid is applied by a conventional coating means such as a gravure coater, a roll coater, and a wire bar, and dried.

[0024]

The present invention will be described more specifically with reference to examples and comparative examples. In the text, "part" or "%" means
Unless otherwise specified, it is based on weight. Example 1 A 4.5 μm thick polyethylene terephthalate film (manufactured by Toray Industries, Inc.,
(Lumirror) on one surface of a hot-melt ink layer coating liquid 1 having the following composition by hot melt coating to a dry coating amount of 3.
The resultant was coated and dried at 0 g / m ² to form a hot-melt ink layer, and the thermal transfer sheet of Example 1 was prepared. On the other side of the base film, a heat-resistant layer coating solution having the following composition was previously applied by gravure coating so that the dry coating amount was 0.3 g / m ² , and dried to form a heat-resistant layer. It is formed.

Hot melt ink layer coating liquid 1 Carbon black (Mitsubishi Chemical Corporation, # 44) 15 parts Paraffin wax (Penetration 11) 40 parts Carnauba wax 10 parts Terpene-phenol resin (SP value 9.0) 30 parts (Yasuhara Chemical Co., Ltd., YS Polystar N125, softening point 125 ° C) Ethylene-vinyl acetate copolymer 5 parts (MI = 150, VA = 19%)

Heat-resistant layer coating liquid Styrene acrylonitrile copolymer resin 11 parts Linear saturated polyester resin 0.3 parts Zinc stearyl phosphate 6 parts Melamine resin powder 3 parts Methyl ethyl ketone 80 parts

Example 2 Heat used in Example 1 above
Changed coating liquid 1 for molten ink layer to coating liquid 2 having the following composition
Otherwise, the thermal transfer of Example 2 was performed in the same manner as in Example 1.
Created a sheet. Hot melt ink layer coating liquid 2 Carbon black (Mitsubishi Chemical Corporation, # 44) 15 parts Paraffin wax (Penetration 11) 40 parts Carnauba wax 10 parts Terpene-phenol resin (SP value 9.07) 30 parts (Yasuhara Chemical Co., Ltd., YS Polystar N125) , Softening point 125 ° C) Ethylene-vinyl acetate copolymer 5 parts (MI = 150, VA = 19%)

Example 3 Heat used in Example 1 above
Changed coating liquid 1 for molten ink layer to coating liquid 3 with the following composition
Otherwise, the thermal transfer of Example 3 was performed in the same manner as in Example 1.
Created a sheet. Hot melt ink layer coating liquid 3 Carbon black (Mitsubishi Chemical Co., Ltd., # 44) 15 parts Paraffin wax (Penetration 11) 50 parts Carnauba wax 10 parts Terpene-phenol resin (SP value 9.0) 20 parts (Yasuhara Chemical Co., Ltd., Mighty Ace G125 , Softening point 125 ° C) Ethylene-vinyl acetate copolymer 5 parts (MI = 150, VA = 19%)

Comparative Example 1 Heat used in Example 1 above
Changed coating liquid 1 for molten ink layer to coating liquid 4 with the following composition
Otherwise, the thermal transfer of Comparative Example 1 was performed in the same manner as in Example 1.
Created a sheet. Hot melt ink layer coating liquid 4 Carbon black (Mitsubishi Chemical Corporation, # 44) 15 parts Paraffin wax (Penetration 11) 40 parts Carnauba wax 10 parts Aromatic modified terpene resin (SP value 8.73) 30 parts (Yasuhara Chemical Co., Ltd., YS Polystar) T0115, softening point 115 ° C) 5 parts of ethylene-vinyl acetate copolymer (MI = 150, VA = 19%)

(Comparative Example 2) Heat used in Example 1 above
Changed coating liquid 1 for molten ink layer to coating liquid 5 having the following composition
Otherwise, the thermal transfer of Comparative Example 2 was performed in the same manner as in Example 1.
Created a sheet. Hot melt ink layer coating liquid 5 Carbon black (Mitsubishi Chemical Corporation, # 44) 15 parts Paraffin wax (Penetration 11) 40 parts Carnauba wax 10 parts Aromatic modified terpene resin (SP value 8.81) 30 parts (Yasuhara Chemical Co., Ltd., YS polystar) T130, softening point 130 ° C) Ethylene-vinyl acetate copolymer 5 parts (MI = 150, VA = 19%)

Using the thermal transfer sheets of the above Examples and Comparative Examples, printing was carried out under the following printing conditions, and the printed matter was evaluated for print quality, abrasion resistance and peeling sound by the following evaluation methods. Perform an evaluation. The printer using the printing conditions was a BC8MK3 printer manufactured by Autoncs, and a printing speed of 40 on FACSON 1C paper.
A barcode pattern was printed under the condition of mm / sec. Evaluation method of print quality For each of the above prints, the transfer state of the barcode is visually observed and evaluated according to the following criteria. ：: The transfer state is good. X: The transfer state is partially defective.

Evaluation Method for Scratch Resistance Each of the above printed matter is subjected to a rubbing test by the following method, and the surface state of the printed matter is visually observed and evaluated according to the following criteria. Testing machine: Suga Test Machine Co., Ltd., wear test machine load
: 500g Moving speed: 30mm / sec Number of reciprocations: 100

Evaluation Criteria: ：: There is no dropout of the printed portion, and there is no stain on the ground portion. Δ: The print portion was slightly dropped, and the ground portion was stained. D: The printed portion was conspicuous and the ground portion was very dirty.

Evaluation Method of Peeling Sound Under the above printing conditions, at the time of printing, the peeling sound of the hot melt ink layer of the thermal transfer sheet peeling from the base film was measured under the following conditions, and evaluated according to the following criteria. I do. Testing machine: manufactured by Rion Co., Ltd., NL-
05A Measurement condition: Measured at a position 1.5 cm from the printed part.

Evaluation criteria: ：: Less than 85 dB in equivalent noise level. X: 85 dB or more in equivalent noise level.

(Evaluation Results) The evaluation results of the above Examples and Comparative Examples are shown in Table 1 below.

[Table 1]

[0037]

As described above, the thermal transfer sheet of the present invention is a thermal transfer sheet in which at least a hot-melt ink layer is provided on one surface of a substrate film, wherein the hot-melt ink layer is made of wax, resin, or coloring. The resin has an SP value of 9 or more, and the content of the resin is 20% by weight or more based on the total solid content of the hot-melt ink layer. As a result, when the above resin is used in a proportion of 20% by weight or more, the wax and the resin in the hot melt ink layer are appropriately incompatible with each other, so that the tack of the resin in the hot melt ink layer at the time of printing is reduced. In addition, the peeling sound of the ink layer peeling from the base film during printing can be suppressed. Further, since the hot melt ink layer contains 20% by weight or more of a resin having an SP value of 9 or more, a hard resin is dispersed in a soft wax, so that the scratch resistance of printed matter is improved. . Further, as a wax of the hot-melt ink layer, a wax having a penetration of 4 or more is used as a main component, so that the hot-melt ink layer has fluidity so that the melt viscosity of the hot-melt ink layer is not too high. This is advantageous in terms of workability and, furthermore, the raw material cost of wax.

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 2C068 AA06 BC03 BC12 BC30 BC33 2H111 AA01 AA10 AA26 AA33 BA03 BA33 BA38 BA53 BA54 BA61 BA63 BA71 BA78 BB05 4F100 AA37 AA37H AJ11B AK01B AK12 AK27 AK33 HB31A13 JA04B JA20B JH10 JK20B JL00 JL01 JL02 JL05 JL10 YY00B

Claims (3)

[Claims] 1. A thermal transfer sheet having at least one hot-melt ink layer provided on one surface of a substrate film, wherein the hot-melt ink layer is composed of a wax, a resin, and a colorant, and has a solubility parameter of the resin (hereinafter referred to as SP). The thermal transfer sheet is characterized in that the content of the resin is 20% by weight or more based on the total solid content of the hot-melt ink layer. 2. The method according to claim 1, wherein the wax is mainly composed of a wax having a penetration of 4 or more.
Thermal transfer sheet described in 1. 3. The softening point of the resin is 120 to 140 ° C.
The thermal transfer sheet according to claim 1, wherein