JPS61255896A - Gradation thermal transfer recording sheet - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a thermal transfer recording sheet capable of gradation recording in a thermal transfer type thermal transfer system using a thermal head.

(B) Conventional technology Traditionally, thermal transfer systems include a thermal sublimation transfer method in which ink containing a heat sublimable dye is formed on a support and the dye is sublimated onto the image receiving paper side by heating to perform recording. Then, a heat-melting ink layer containing colored dyes and pigments is formed on the support (hereinafter referred to as donor sheet), and transferred to the image receiving paper side by heating.
A thermal sublimation transfer method that performs transfer and recording is known. Since the thermal sublimation transfer method transfers and records the dye as a gas, the gradation of the image is good and it is seen as a promising full-color recording method, and inventions have been made to improve the dye stainability of the image-receiving paper for this system. ing. (Unexamined Japanese Patent Publication No. 57-91296
, JP-A-57-107885, JP-A-57-13719
1. JP-A-59-59495, however, the thermal sublimation transfer method has the disadvantage that the sublimation temperature of the dye is high, so it requires a lot of heating time and the recording speed is slow. It is also possible to use a dye with a low sublimation temperature, but the re-sublimation of the dye results in poor image storage stability, and furthermore, because it is a dye, the image's light resistance is also poor. For these reasons, we will take back the
A lot of research is being done into methods of producing gradation using the heat-fusion transfer method, which has a fast recording speed and good archival stability.

For example, in JP-A-57-56295, a layer of hot bath-fusible ink (AJt-) is also provided on a support, which is arranged on the ink layer in the form of halftone dots with a distance t from each other. A large number of spot-shaped heat-fusible ink layers with a low melting point are provided, and when heated, an ink transfer IIkt--instead, an intermediate D4 is produced.

Further, JP-A-59-64391 discloses a layer containing an image-forming substance capable of forming an image by heating, which is sequentially formed on a support.
The image-forming material is coated with an image-receiving material that can receive the image-forming material and transfer it to the transfer medium by heating, thereby controlling the amount of the image-forming material thermally transferred to the image-receiving paper side.

(Q. Problems to be solved by the invention The patent publications cited in the prior art section above have various problems.

For example, JP-A-57-56295, JP-A-59-64391
All of the publications attempt to create gradation by devising the layer structure of the ink applied to the support. That is, the donor sheet must be coated twice to complete the process, resulting in high manufacturing costs.

In addition, conventional single-layer donor sheets are coated with a hot-melt ink containing colored dyes and pigments, binders, waxes, and other additives on a support by a gravure method or a flexographic method. The waxes used are melted and applied, so the coating layer has a high packing density and has good conductivity of the heat given by the thermal head, so the ink layer is almost completely formed in accordance with the shape of the thermal head. Perhaps because it is dissolved in No gradation is obtained,
The image is a very high contrast 0N-OPFZ value recording color recording. Therefore, in this industry, donor sheets with different transfer densities are used to print multiple times overlapping each other to create density gradations, and at the same time, an area gradation method is also used to control the number of halftone dots in the printing matrix. I am trying to obtain a high-gradation image using a complicated method.

This has the disadvantage that the manufacturing cost of the donor sheet is high and the printing speed is also slow.

The present inventors conducted research with the aim of solving these drawbacks and obtaining a thermal transfer recording sheet 1 capable of performing gradation recording.

(L)) Means for Solving the Problems The present inventors conducted intensive research to solve these drawbacks, and as a result, were able to provide a gradation thermal transfer recording sheet.

That is, in a thermal transfer recording sheet in which a heat-melting ink layer containing colored dyes and pigments, binders, and waxes is coated on one side of a support, gallic acid and/or its derivatives are added to the heat-melting ink. Furthermore, by containing acetylene glycol, it was possible to provide a thermal transfer recording sheet capable of recording nine gradations.

In addition, the gradation thermal transfer recording sheet of the present invention has good dispersibility in other components of dyes and pigments when producing heat-melting inks due to the acetylene glycol content, and also has good dispersibility with the support. It is characterized by excellent adhesion.

Specifically, the gallic acid and/or its derivatives include gallic acid, methyl gallate, ethyl gallate, propyl gallate, isoamyl gallate, octyl gallate, lauryl gallate, stearyl gallate, trimethoxy gallate. , trimethoxy gallic acid methyl ester, gallic acid 3-methyl ether, gallic acid 4-methyl ether, gallic acid 3,4-dimethyl ether, gallic acid 3,
It consists of at least 1s selected from 5-dimethyl ether.

More preferably, the gallic acid derivative consists of at least L species selected from gallic acid alkyl esters, methyl gallate, ethyl gallate, propyl gallate, isoamyl gallate, octyl gallate, lauryl gallate, and stearyl gallate. It is.

The hot-melt ink of the present invention includes colored dyes and pigments, a binder,
By containing gallic acid and/or its derivatives in the wax component in an amount of 5 to 50% by weight based on the total weight of the hot-melt ink, gradation recording can be obtained. Preferably it is 10 to 30 weight percent.

In addition, acetylene glycol includes 2,4,7,9-tetramethyl-5-decyne-4,7-diol and its ethylene oxide adduct, 3,6-dimethyl-4-octyne-3,
It consists of at least one kind selected from 6-diol.

Acetylene glycol is present in an amount of 0.1 to 20 weight percent, preferably 0.5 to 10 weight percent, based on the dry solids content of the hot melt ink.

The gradation thermal transfer recording sheet of the present invention can produce images with high density gradation by simply coating a support in a single layer. Images with color gradation can be created by creating a thermal transfer recording sheet that is partially coated with heat-melting ink consisting of at least yellow, magenta, and cyan colors on a support instead of coating with a single color. Obtainable.

Furthermore, because the dye and pigment in the heat-melt ink have good dispersibility and the ink has excellent adhesion to the support, it is possible to use a gradation thermal transfer recording sheet coated with a homogeneous heat-melt ink layer. can be manufactured.

The reason why the thermal transfer recording sheet of the present invention has a sandy gradation is not very clear, but in the case where the only component that provides the transfer effect of the heat-melting ink in a normal thermal transfer recording sheet is wax, In contrast, the uninvented mixture of gallic acid and/or its derivatives has a high melting point, and at low energy, the transfer is suppressed to 1/kt, and the energy gradually increases. The amount of transcription increases in proportion to I)
It is thought that density gradation appears. In addition, when the components of the present invention are mixed, when the heat-melting ink layer on the thermal transfer recording sheet is enlarged, the ink is arranged in the form of particles on the support9, and the particles change depending on the energy of the thermal head. It is thought that there is a tendency for the density gradation to appear more easily because the ink of the shape is independently transferred to the image receiving paper surface.

The inclusion of acetylene glycol in the present invention provides a synergistic effect on the above-mentioned advantages due to its characteristics of uniform dispersion of dyes and pigments and excellent adhesion to the support.

Furthermore, the types, amounts, and melting points of binders, waxes, dyes and pigments, which are the main components of the heat-melting ink, are also thought to have a subtle influence.

For example, waxes have a melting point of 50°C to 200°C.
, preferably waxes at 60 to 150°C are good;
If the melting point is lower than 50° C., even if the ink I is in the form of particles, the sensitivity will be too high during thermal transfer, making it impossible to obtain density gradation. On the other hand, if the melting point is higher than 2-00 DEG C., the thermal head requires high energy and the amount of thermal transfer is small, which is not practical.

Typical examples of such waxes are shown below, but the waxes are not limited thereto.

As waxes, for example, vegetable waxes,
Rice wax, Japanese wax, candelilla wax, carnauba wax, etc. Animal waxes include lanolin, beeswax, chemical lac wax, mineral waxes include montan wax, synthetic waxes include paraffin wax, microcrystalline wax, etc. Wax, oxidized paraffin wax, chlorinated paraffin wax, ricinoleic acid amide, lauric acid amide, erucic acid amide, palmitic acid amide, oleic acid amide,
12-hydroxystearic acid, distearyl ketone,
Metal soaps such as ethylene bisstearamide include sodium stearate, sodium palmitate, potassium laurate, potassium myristate, calcium stearate, zinc stearate, aluminum stearate, magnesium stearate, lead stearate, dibasic Higher fatty acids such as barium stearate include palmitic acid and stearic acid; higher alcohols include palmityl alcohol, stearyl alcohol, and ceryl alcohol; and synthetic polyalcohols include polyethylene glycol and polyglopylene glycol. be able to.

Next, as the first dye/pigment, any of water-soluble dyes, oil-soluble dyes and pigments, disperse dyes, and solvent-insoluble organic pigments can be used, and does not directly affect the quality of gradation. Each of the above types of dyes and pigments can be used depending on the coating method.

In particular, water-soluble dyes are preferably used for water-based coating and solvent coating. Further, for those that dissolve in organic solvents, solvent coating is preferable, and in the case of hot melt coating, either dissolution or dispersion may be used.

It is better to make the dye and pigment into fine particles with a particle size of about 1 μm or less, so that the transferred image does not have roughness. Although there are sublimation type dyes, the dyes of the present invention cannot fully exhibit the sublimable '+A' ability.

However, as long as it is used as a coloring material, it does not impede the present invention and may be used without any problem.

The dyes and pigments are specifically exemplified below, but are not limited to these, and 28I or more may be used in combination.

Water-soluble dyes include nitroso dyes, azo dyes (mono,
(bis, tris, tetrakisazo dyes), stilbene azo dyes, ketoimine (diphenylmethane) dyes, triphenylmethane dyes, xanthine dyes, acridine dyes, quinoline dyes, methine dyes, polymethine dyes, thiazole dyes, indamine dyes, azine dyes, thiazine dyes , oxyketone dyes, anthraquinone dyes, and 7-talocyanine dyes. To give a more specific example, the nitroso dye is mordant geline 4 (C
, L10005, C and I are in parentheses below.

At-indicated), as an azo dye Direct Red 28
(22120), Direct Orange 71 (40205) as a stilbene azo dye, Basic Niro 2 (410oo) as a ketoimine dye, Basic Blue 1 (42025) as a triphenylmethane dye,
As a xanthine dye, Acid Red 52 (4510
0), Basic Orange 23 as an acridine dye
(46075), Acid Yellow 2 (47010) as a quinoline dye, Direct Yellow 59 (49000) as a methine dye, Acid Blue 59 (50315) as an azine dye, Mordand Blue 10 (51030) as an oxazine dye, Thiazine The dye is Basic Blue 9 (52015), the anthraquinone dye is Acid Blue 45 (63010), and the phthalocyanine dye is Direct Blue 86 (7).
4180).

Examples of oil-soluble dyes include azo dyes, azofluorophorum complex dyes, anthraquinone dyes, and phthalocyanine dyes. To give more specific examples, examples of azo dyes include Solvent Yellow 2 (C, 1, 11020, hereinafter C, 1, A'(+'' is shown in parentheses), Solvent Orange 1 (11920), Full Vent Red 24 (26
105), Full Bent Brown 3 (11360), etc., and Solvent Yellow 19 (11360) as an azo metal complex dye.
13,900 people), Solvent Orange 5 (18,745A
), Blue Vent Red 8 (12715), Solvent Brown 37, Solvent Brown 123 (12195)
Examples of anthraquinone dyes include Solvent Violet 13 (60725) and Solvent Blue 11 (
61525), Bullpent Green 3 (61565), and Solvent Blue 2 as a phthalocyanine dye.
5 (74350) etc.

Examples of disperse dyes include aminoazo or ami/anthraquinone dyes, nidroarylamine dyes, and the like. More specifically, examples of aminoazo dyes include Disbirds Yellow 3 (C, 1, 11855, hereinafter C, 1, A is shown in parentheses), Disbirds Orange 3 (11005), and Disbirds Red 1 (11110).
), Disperse Violet 24 (11200), Disperse Blue 44, etc. As an aminoanthraquinone dye, Diverse Orange 11 (60700
), Days Birds Red 4 (60755), Days Birds Violet) 1 (61100), and 7” Days Birds Blue 3 (61505).

Nidroarylamine dyes include Disverse Yellow 1 (10345) and 42 (10338).

Pigments include azo pigments (monoazo, bisazo, condensed azo pigments), dyeing lake pigments (acid dye lake, basic dye lake, mordant dye lake pigment), nitro pigments, nitroso pigments, phthalocyanine pigments, and high-grade pigments (built-up dye lake pigments). Examples include dye pigments, metal complex salt pigments, perylene pigments, isoindolinone pigments, and quinacridone pigments).

To give a more specific example, the azo pigment is Hansa Yellow G (C, 1, 11680, hereinafter in parentheses is C, 1,
), Hansa Yellow R (12710), Pyrazolone Red B (21120), Permanent Red R (1
2085), Lake Red C (15585), Brilliant Carnone 6B (15850), Permanent Amine FB (12490) (all monoazo pigments), Benzidine Yellow (21090), Benzidine Yellow R (2
1100), Permanent Yellow NCR (20040)
Examples include bisazo M pigments containing carbon or more), chromophthal yellow, and chromophthal red (condensed azo pigments containing carbon or more). As a dyeing lake pigment, quinoline yellow lake (47005
), Eosin Lake (45380), Alkaline Blue Lake (42750A, 42770A) (all acid dye lake pigments), Rhodamine Lake B (45170), Methyl Violet Lake (42535), Victoria Blue Lake (44045), Malachite Green Lake (
42,000) (all basic dye lake pigments), alizarin lake (ssooo) (mordant dye lake pigments), and the like. Naphthol Yellow 8 (1031) as a nitro pigment
6), Pigment Green B (10
006), naphthol green B (10020), phthalocyanine pigments include metal-free phthalocyanine blue (74100), phthalocyanine blue (74160)
, Phthalocyanine Green (74260), etc.

Anthrapyrimidine yellow (684) is a high-grade pigment.
20), Indance Brilliant Orange GK (5
9305), Indan Stremburu-R8 (69800)
, Thioindigo Red B (73300) (vat dye pigment), Nickel Azo Yellow (12775) (metal complex pigment), Perylene Red (71140), Berylene Scarlet (71137) (perylene pigment), Ininotrino Yellow (isoindolinone pigment), Quinacridone Red Y (46500), Quinacridone Magenta (73915), etc.

In addition, carbon black (C61,7
7265).

As the binder, either a water-soluble binder or a water-soluble binder can be used, and the water-soluble binder is used for solvent coating and for aqueous/drainable systems. Drainage soluble binders are used in solvent coatings and hot melt coatings.

Typical examples of such binders are illustrated below, but the binder is not limited thereto, and two or more binders may be used in combination.

As the binder, for example, polyvinyl alcohol,
Methylcellulose, gelatin and droxyethylcellulose, carboxymethylcellulose, gum arabic, starch and its derivatives, casein, polyvinylpyrrolidone,
Butyral resin, ethylene ethyl acrylate, styrene-butadiene copolymer, vinyl acetate resin, vinyl acetate copolymer, acrylic resin, methyl methacrylic resin, styrene-acrylonitrile resin, ethylene-vinyl acetate copolymer, polyester resin , petroleum resin, etc.

The amount of dye and pigment used for the main components of heat-melting ink is 0.
．． 5 to 40 weight percent, preferably 1 to 25 weight percent, waxes IO to 70 weight percent,
Preferably from 20 to 60 weight percent, binder from 5 to 60 weight percent, preferably from 10 to 50 weight percent.

In the present invention, the above-mentioned gallic acid and/or its derivatives, acetylene glycol, colored dyes and pigments, binders,
Although waxes are the main component, other additives such as surfactants, dispersants, antistatic agents, antioxidants, and ultraviolet inhibitors may also be added when coating or printing on the support. good.

Supports include capacitor paper, typewriter paper,
Thin paper such as tracing paper, synthetic paper, cellophane paper,
In history, synthetic resin films such as polyester film, polyimide film, polyethylene film, polycarbonate film, polystyrene film, and Teflon film are used as they are or after heat-resistant treatment to prevent them from sticking to the thermal head.

Coating machines include hot melt coater, air knife coater, roll coater, blade coater, bar coater,
It is coated with a known coater such as flexo method,
Known printing machines such as gravure printing machines may also be used.

In order to obtain a full-color image, at least yellow, magenta, and cyan color inks are partially printed on the same four carriers in a line-sequential, area-sequential, or dot-sequential manner.

Note that solvent coating can be carried out using general solvents, such as methanol, ethanol, isopropyl alcohol, toluene, methyl ethyl ketone, acetone, ethyl acetate, etc., as appropriate.

(g) Function The gradation thermal transfer recording sheet of the present invention has gallic acid and/or its derivatives and acetylene glycol added to a heat-melting ink containing colored dyes and pigments, binders, and waxes as main components on one side of the support. By containing it, recording with a high degree of gradation is possible.

With conventional thermal transfer recording sheets, when forming images using a thermal head, when printing starts from a low energy state, there is no difference in transfer density from the energy range where transfer occurs to high energy, and the transfer density remains constant. It is not possible to obtain gradation.

On the other hand, since the thermal transfer recording sheet of the present invention contains gallic acid and/or its derivatives and acetylene glycol in the cough ink composition, it has excellent dispersibility of dyes and pigments of the ink and adhesion of the ink to the support, and has low energy consumption. It shows a smooth transfer density from a high energy area to high energy, and can obtain gradation. This can control transferability by adding gallic acid and/or its derivatives, which have a high melting point, to waxes with high transfer efficiency, and shows transfer with gradation. It works effectively by containing it.

Further, acetylene glycol works effectively when it is contained in a proportion of 0.1 to 20 lil.

V) Examples Hereinafter, the present invention will be specifically explained with reference to Examples.

Note that "parts" in Examples and Comparative Examples indicate parts by weight of solid content.

Example 1 In producing a 1-16 gradation thermal transfer recording sheet (donor sheet), the composition of the heat-melting ink was as follows, and a 9μ PET film that had been heat-resistant treated using a Mayer bar was put through a dryer. Method 4 wy1 (solvent coated.

SOT Blue G (Hodogaya Chemical, melting point 74-75
°C) 10 parts by weight 150°F Paraffin wax 40 parts by weight Polyvinyl alcohol 20 parts Lauryl gallate (melting point 96°C) 30 parts by weight 2.4,7.9-
3 parts by weight of tetramethyl-5-decyne-4,7-diol The hot-melt ink was prepared as a 20% ethanol dispersion using a ball mill.

The ink side of the prepared donor sheet was printed on plain paper (image receiving paper for thermal transfer paper, manufactured by Mitsubishi Paper Mills, trade name: TTR-PW).
) and 16. OVK pulse width'
io, thermal printing was performed at intervals of 0.2 milliseconds from 2 milliseconds to 3.0 milliseconds, and the transferred image density was measured using an optical densitometer (Macbeth RD514 model). The results are shown in Table 1. Moreover, the acetylene glycol of the present invention,
That is, 2゜4.7,9-tetramethyl-5-decyne-4,
Due to the addition of 7-diol, the donor sheet 11 was repeatedly bent to check the degree of peeling of the ink layer, but no peeling occurred.

Experiments 1-2 and 1-3, as well as 1-1 to 1-3 as comparative examples, were conducted in the same manner as 1-1, and the results are listed in Table 1.

In Table I, regarding the adhesion between the PET film and the heat-melting ink layer, those in which peeling of the ink layer does not occur are marked as ○, and those in which peeling occurs (Comparative Example 1-1.1-2) and the ink layer are Items that become sticky and have an adhesive effect (Comparative Example 1-3)
was marked as ×.

As is clear from Table 1, Examples 1-1 to 1-3 are as follows:
In contrast, in the comparative example 1-1, the transfer density is high from the low pulse width region and the gradation is high. It had no sex.

In Comparative Example 1-2, t! There was no adhesion between the PET film and the ink layer, resulting in peeling. However, it did have tonality. In Comparative Example 1-3, the adhesion between the PET film and the ink layer was so excessive that the ink layer became sticky and could not be used.

(Leaving space below) Example 2 To prepare a gradation thermal transfer recording sheet (donor sheet), the following hot-melt heat-melt ink was prepared and applied to a heat-resistant 9 μPET film. Hot-melt coating was carried out to give a coating thickness of 3.5 f/m'.

Carbon black 10 parts by weight Paraffin wax (Hiki Seiro product name 5P-0145) 5
3 parts by weight Ethylene-vinyl acetate resin 6 parts by weight Petroleum resin (manufactured by Arayo Kagaku, trade name Alcon M) 6 parts by weight Ethyl gallate (melting point 150-153°C) 25 parts by weight 3
．． The donor sheet prepared with 5 parts by weight of 6-dimethyl-4-octyne-3,6-diol was printed in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 2 A donor sheeter was prepared in the same manner as in Example 2 except that ethyl gallate was removed and the amount of paraffin wax was changed to t-78 parts by weight.

Printing was carried out in the same manner as in Example 2, and the results are shown in Table 2.

As is clear from Table 2, Example 2 shows a gradation density change and good adhesion between the PET film and the ink layer, whereas Comparative Example 2 shows that the PET film and the ink layer have good adhesion. Although the adhesion with the ink layer was good, high density was exhibited from the low pulse region and no gradation was obtained.

(The following is a blank space) q Effects of the Invention The present invention is characterized by containing gallic acid and/or its derivatives and acetylene glycol in the heat-melting ink, thereby achieving excellent layering properties of the ink on the support and extremely high concentration. In addition to single-color coating, color images with high color reproducibility can be obtained by using partial coatings of three colors (yellow, magenta, cyan, and four colors), and are of industrial significance. This makes it possible to provide a thermal transfer recording sheet with excellent gradation.

Claims (1)

[Scope of Claims] 1. A thermal transfer recording sheet in which a heat-melting ink layer containing colored dyes and pigments, binders, and waxes as main components is coated on one side of a support, wherein the heat-melting ink is coated with a gallic layer. A gradation thermal transfer recording sheet characterized by containing an acid and/or a derivative thereof and acetylene glycol. 2. The gallic acid and/or its derivatives include gallic acid, methyl gallate, ethyl gallate, propyl gallate, isoamyl gallate, octyl gallate, lauryl gallate, stearyl gallate, trimethoxy gallic acid, and methyl trimethoxy gallate. Ester, gallic acid 3-methyl ether, gallic acid 4-methyl ether, gallic acid 3,4
The gradation thermal transfer recording sheet according to claim 1, which is at least one selected from -dimethyl ether and gallic acid 3,5-dimethyl ether. 3. The gallic acid and/or per total electric charge of the heat-melting ink.
2. The gradation thermal transfer recording sheet according to claim 1, wherein the amount of the gradation thermal transfer recording sheet is 5 to 50% by weight. 4. The acetylene glycol is 2,4,7,9-tetramethyl-5-decyne-4,7-diol and its ethylene oxide adduct, 3,6-dimethyl-4-octyne-3
, 6-diol. 5. The gradation thermal transfer recording sheet according to claim 1, wherein the acetylene glycol is contained in an amount of 0.1 to 20 weight percent based on the dry solid content of the heat-melting ink.