JPS60239285A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To prevent resolution from being lowered at the time of thermal transfer, by a method wherein a heat-fusible coloring material layer comprising a high boiling point solvent is provided on a base, and a thermally transferrable surface layer is provided thereon to produce a thermal transfer recording medium. CONSTITUTION:The heat-fusible coloring material layer comprising a high boiling point solvent is provided on the base such as a paper, a resin film, a paper- resin film composite material and a metallic sheet by solvent coating, hot-melt coating or the like. Then, the thermally transferrable surface layer is provided on the coloring material layer by solvent coating or the like to produce the thermal transfer recording medium. The high boiling point solvent can be selected from those having a boiling point of not lower than 120 deg.C, preferably, not lower than 160 deg.C, e.g., tricresyl phosphate, dibutyl phthalate, linseed oil or beef tallow.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thermal transfer recording medium, and more specifically, it provides a good dye transfer image even on plain paper with low surface smoothness without reducing resolution. The present invention relates to a thermal transfer recording medium that can be used.

[Prior Art] A thermal transfer recording medium has been conventionally used as a recording medium for transferring and forming an image on a recording sheet such as plain paper using a thermal printer, a thermal facsimile, or the like. This heat-sensitive transfer recording medium has at least one heat-melting coloring material layer on a support, and the heat-melting coloring material layer includes a coloring agent made of a dye such as a pigment, and a heat-melting material. Layers containing these are known. Also,.

As a support, in order to obtain good reproducibility of the dye transfer image obtained from the heat-melting color material layer coated on the support,
Films with excellent surface smoothness and dimensional stability are used.

A dye transfer image (printed image) obtained from such a conventional thermal transfer recording medium has the disadvantage that, when the recording sheet is plain paper, the image is unclear unless the surface is extremely smooth. Regarding this point, for example, it is possible to obtain a relatively clear dye transfer image even on paper with low smoothness by incorporating a large amount of heat-fusible substance or colorant into the coloring material layer. However, it is necessary to increase the thickness of the heat-melting coloring material layer, resulting in a disadvantage that the resolution is reduced. Another disadvantage is that background stains (fogging) occur. On the other hand, in order to obtain a good transferred image on plain paper with low smoothness, the following technique can be considered. For example, the melt viscosity of the heat-melting component of the coloring material layer is reduced so that it flows into the recesses of the paper. For example, there are methods to do this. However, as a result of the inventor's study of this technology, it was found that background stains (fogging)
It has been found that this method has the disadvantage of easily causing

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned circumstances, and can be applied to plain paper with low surface smoothness without reducing resolution during thermal transfer. A technical problem is to provide a clear dye transfer image without fogging.6 [Means for solving the problem] The thermal transfer recording medium of the present invention to solve the above technical problem is In a heat-sensitive transfer recording medium having a heat-melt coloring material layer on a support, the heat-melting coloring material layer contains a high-boiling point solvent, and a heat-melting surface layer is provided on the heat-melting coloring material layer. It is characterized by having the following.

The thermal transfer recording medium of the present invention has a heat-melting coloring material layer containing a high boiling point solvent as a lower layer on a support, thereby improving resolution and adhesion to the transfer paper. A thermally transferable surface layer containing no high boiling point solvent is provided as an upper layer to prevent background staining (fogging) on the transfer paper.

The present invention will be described in further detail below.

The thermal transfer recording medium of the present invention has at least a heat-melting coloring material layer on a support, and the coloring material layer is a heat-melting coloring material layer containing at least a high boiling point solvent.

As for the composition of the heat-melting coloring material layer of the present invention, the composition of a normal heat-melting coloring material layer (ink layer) may be employed without any particular restriction, except that the high-boiling point solvent of the present invention is contained.

The heat-melting coloring material layer in the present invention is a coloring material layer that is partially or entirely transferred to the receiving paper by heat.

The high boiling point solvent that can be used in the heat-melting color material layer of the present invention can be selected from those having a boiling point of 120°C or higher, more preferably 160°C or higher. Specific examples include phosphorus-resistant esters such as tricresyl phosphate and triphenyl phosphate; phthalate esters such as dibutyl phthalate and dioctyl phthalate; vegetable oils such as linseed oil, rapeseed oil, castor oil, and turpentine oil; Animal oils such as lard and beef tallow; Mineral oils; Higher fatty acids such as lauric acid and capric acid; Lauryl alcohol,
Examples include higher alcohols such as decyl alcohol; these may be used alone or in combination of two or more.

The colorant to be contained in the heat-melting color material layer of the present invention may be appropriately selected from dyes and pigments. Examples of dyes include basic dyes, oil-soluble dyes (including oil-soluble metal complex dyes), and acidic dyes. The dye may be selected from among dyes, direct dyes, disperse dyes, etc. These dyes may also be ballasted dyes. On the other hand, as the pigment, in addition to organic pigments such as tutarocyanine pigments, inorganic pigments such as carbon black can be used.

The coloring agent to be contained in the heat-melting coloring material layer of the present invention is particularly preferably non-sublimable, and as a non-sublimating colorant, it is necessary to add a heat-melting substance to a recording sheet such as plain paper during heating recording. The non-sublimable coloring agent preferably used in the present invention is a non-sublimable coloring agent that can be transferred and has a color. It is a pigment excluding pigments (including those that contain pigments).

Basic dyes preferably used as the coloring agent of the present invention include, for example, crystal violet (C,I).

42555), malachite green (G, 1.4200
0), methyl violet (G, 1.42535),
Triphenylmethane dyes such as Victoria Blue (C;, 1.44045), Mazienta (C, 1,42510), diphenylmethane dyes such as Auramine (C, 1, 1l155), Astraphloxin FF (C, E,
48070), Eisenkatilon Yellow 3GLH (
Hodogaya Chemical Industry Co., Ltd. product, C, 1,48055), Eisenriki Chiron Red 68H (C:, 1.48020) Astrazone Golden Yellow GL (Bayer Co., Ltd. product,
C.I.

Methine and azamethine dyes such as 48054), a
- Dami7B (N, 1.45170), l:” - Dami6G (G, r.

45160), thiazole azo and triazole azo dyes such as Astrazone Blue GL (G, 1.11052), Astrazone Red F3BL (G, 1.1I055), Eisen Chiron Blue-5GH (C :, 1l1085), methylene blue (
Quinoneimine dyes such as C, 1, 52015), Eisen Chiron Red GTL) 1 (C:, 1.11085)
, Cepron Yellow 3RL (Dupont product, C, 1
,1108? ),, Astrazon Blue-FGI.

Examples include insulating azo dyes and anthraquinone dyes having an onium group at the structural end, such as (c, 1.61512).

Oil-soluble metal complex dyes include, for example, symmetric l:2 type azo metal complex dyes, asymmetric l:2 type azo metal complex dyes, l
: I-type azo metal complex dyes, azomethine metal complex dyes, formazan metal complex dyes, metal phthalocyanine dyes, and organic base salts of these dyes. Specifically, Eisenspiron Yellow 3RH (Hodogaya Chemical Co., Ltd. product, G, 1. Solvent Yellow 25)
, Zapon Fast Yellow R (BASF product, G,
1.18880), Eisenspiron Orange 2RH (
G.
5), Zapon Fast Violet BE (C, 1, 1
211] 6), Cyanine Blue BB (Sumitomo Chemical Co., Ltd. product, 1.?4180), Varifast Black $1
3804 (Orient Chemical Co., Ltd. product, C, 1, 12185
), Eisen Subiron Yellow 3RH Special (C,
1, Solvent Yellow 25:l), Eisens, Piron Orange 2RH Special (C, 1, Solvent Orange 40:1), Eisenspiron Blue 28NH
((:, 1, Solvent Black 117), Zapon Fast Blue) IFL (C:, 1.74350), Eisens Viron Black 8H Special (C, 1, Solvent Black 22:l), and the like.

Acidic dyes include, for example, G, 1. acid yellow 18,
G.1. Acid Red 37, G, 1. Acid Blue 62, G, 1. Acid Orange 101G, j, Acid Blue 83, G, 1. Acid black O1 etc. are mentioned.

The direct dye is C,1, Direct Yellow 44.0. I
.

Direct Yellow 142, C;, 1. Direct Yellow 12, C, 1, Direct Blue 15, C, I-
Direct Blue 25, C, 1, Direct Blue 24
8, C, 1, Direct Red 81. C, 1, Direct Red 8, G, 1. Direct Red 31. C,1
, Direct Black 154, C,1, Direct Black 17, and the like.

Disperse dyes are c, r: disbose yellow 5, C:,
1. Disbors Yellow 51. C, 1, Disbo's Yellow 64, c;, r, Disbo's Red 43,
C, 1, Disbo's Red 54, G, 1. Disbo's Red 135, C, 1, Disbo's Blue 56, G
, 1. Examples include Disbo's Bluff 3, c, r, and Disbo's 81.

The ballasted dyes used in the present invention are dyes having at least one ballast group in the dye matrix, such as azo dyes, azomethine dyes, anthraquinone dyes, naphthoquinone dyes, sterine dyes, quinophthalo dyes, and phthalocyanine dyes. Ballast groups are groups that are highly soluble in heat-melting substances, such as alkyl groups, cycloalkyl groups, aralkyl groups, alkoxy groups, alkylsulfonylamino groups, alkylsulfonyl groups, hydroxylalkyl groups, cyanoalkyl groups, alkoxycarbonylalkyl groups, and alkoxy groups. It is a group having an alkyl group or an alkylene group having 6 or more carbon atoms, such as an alkyl group or an alkylthio group. In particular, a ballast group having at least one alkyl group having 6 or more carbon atoms in the molecule is preferable.9 As an example of the structure of the ballasted dye preferably used in the present invention, a patent filed by the present applicant on April 25, 1980 Examples of the heat-melting substance used in the heat-melting coloring material layer of the present invention include those described in Application (^), but the present invention is not limited thereto. value) or softening point (measured value by ring and ball method) of 40 to 120° C1, preferably 60 to 1
It is a solid or semi-solid substance at 20°C, and specific examples include plant waxes such as carnauba wax, wood wax, auriculie wax, and esparto wax, and animal waxes such as beeswax, insect wax, shellac wax, and spermaceti wax. In addition to waxes such as petroleum waxes such as wax, paraffin wax, microcrystalline wax, ester wax, and oxidized wax, and mineral waxes such as montan wax, osikerite, and ceresin; palmitic acid, stearic acid, margaric acid, behenic acid, etc. higher fatty acids; higher alcohols such as palmityl alcohol, stearyl alcohol, behenyl alcohol, marganyl alcohol, myricyl alcohol, eicosanol; cetyl palmitate, myricyl palmitate,
Higher fatty acid esters such as cetyl stearate and myricyl stearate; amides such as acetamide, propionic acid amide, palmitic acid amide, stearic acid amide, and amide wax; ester gum, rosin maleic acid resin, rosin phenol resin, hydrogenated rosin, etc. Rosin derivatives; polymeric compounds such as phenol resins, terpene resins, cyclopentadiene resins, and aromatic resins; higher amines such as stearylamine, behenylamine, and palmitinamine; polyethylene oxides such as polyethylene glycol 4000 and polyethylene glycol eooo These may be used alone or in combination of two or more. Among these, higher amides such as palmitic acid amide, stearic acid amide, oleic acid amide, and amide wax are particularly preferred. Also, JP-A-54-68
The "thermofusible solid component that is solid at room temperature" described in Japanese Patent Publication No. 253 and the "vehicle" described in Japanese Patent Application Laid-Open No. 105579/1982 may be used.

The low melting point substance used in the heat-melting coloring material layer of the present invention is particularly suitable for use in combination with hard wax and soft wax (one kind or two kinds of each).
species) is preferred. Hard wax [25℃ (100g
) Examples of waxes with a penetration degree (according to JIS K 2530) of less than 8 include: ■ Ester waxes (carnauba wax, Montanosix, etc., manufactured by Knox and Hoechst) 1 oechst
Wax E, F, KPJPS, BJ, OP, ON,
Synthetic ester wax such as X22゜U and 0), ■
Oxidized wax (wax obtained by oxidizing wax such as paraffin wax and microcrystalline wax, NPS-111210, NFS-6 manufactured by Nippon Seiro Co., Ltd.)
115, PETR0NAB^G manufactured by Toyo Petrolite Co., Ltd.
, C:ARI]Is 314, etc.), 18+ low molecular weight polyethylene wax (particularly those with a molecular weight of 300-1000, such as POLYWAX 500 and 655 manufactured by Toyo Petrolite), t4+ acid 7x (H, manufactured by Hoechst)
oechst Wax S and I, P, etc.). In addition, soft wax [25℃ (+oog
) Penetration (according to JIS K 2530)
Examples of waxes with a diameter of 8 or more include microcrystalline wax (mouth surface microwax 155°+a
o (manufactured by Elki Oil Co., Ltd.), it-arc-tcigo
,ot-arc-2oe5゜1('I-AIC-209
5,)It-MIC-1070,)II-WIG-1
045, old-MIC-2045 (manufactured by 8Kiseirosha),
5TARWAX 100. BE 5QUARE175.
185. VICTORY, ULTRAFLEX (manufactured by Toyo Petrolite Co., Ltd.), stearic acid, behenic acid, stearyl alcohol, white wax, beeswax, dodecyl stearate, stearon, sorbitan monostearate, polyoxyethylene monostearate, or Diacarna 30 and Diakaruna PA30L (manufactured by Mitsubishi Kasei Corporation). In addition, when such hard wax and soft wax are used in combination, the weight ratio used is: (1) = 9 to 9:1 (more preferably 2:8 to 8
:2) is fine.

It is preferable that the heat-melting color material layer of the present invention contains a softener. The softener used in the present invention preferably has a softening point (measured by the ring and ball method) of 40 to 200°C, and either a wood-philic polymer or a hydrophobic polymer can be used. Examples of hydrophilic polymers include gelatin, gelatin derivatives, cellulose derivatives, proteins such as casein, natural products and natural product derivatives such as polysaccharides such as starch, water-soluble nylon, polyvinyl alcohol, polyvinylpyrrolidone, and acrylamide polymers. Examples include synthetic water-soluble polymers such as polyvinyl compounds, and vinyl-based and polyurethane-based polymer latexes. As a hydrophobic polymer, U.S. Pat. No. 3,142
, No. 586, No. 3,143, 38θ, No. 3,062,
No. 674, No. 3,220,844, No. 3,287.2
Examples include the synthetic polymers described in No. 89 and No. 3,411.911. Preferred polymers include polyvinyl butyral, polyvinyl formal,
Cellulose derivatives such as polyethylene, polypropylene, polyamide, ethyl cellulose, cellulose acetate, polystyrene, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, ethylene-ethyl acrylate, ethylene-vinyl acetate, vinyl chloride-vinyl acetate copoly2
-1 vinyl chloride-vinyl acetate-maleic acid-terpolymer, acrylic resin such as polymethyl methacrylate,
Examples include polyisobutylene, rosin derivatives such as ester gum, petroleum resin, coumaron indene resin, cyclic rubber, chlorinated rubber, and the like. In the present invention, one or a combination of two or more of these softeners may be used.

Although the composition ratio of the heat-melting coloring material layer of the present invention is not limited,
The heat-melting substance is 50 to 85 parts (more preferably 70 parts) to the total solid content of the coloring material layer ioo parts (parts by weight, the same applies hereinafter).
~85 parts), 5 to 20 parts of colorant, and 0.1 part of high boiling point solvent.
~20 parts (more preferably 1 to 10 parts), softener: 0 to
30 parts (more preferably 1 to 10 parts).

The dry thickness of the heat-melting coloring material layer in the present invention may be the same as that of a normal heat-melting coloring material layer, for example, 15 g or less, more preferably 9 g or less, particularly preferably 9 g or less. are 1 to 7p, II.

The heat-melting coloring material layer of the present invention includes 4==p=in addition to the above components,
Various additives may be included, however, the content of the additives is preferably less than 50% by weight. For example, vegetable oils such as castor oil, linseed oil, olive oil, animal oils such as whale oil, and mineral oils may be suitably used.

The heat-transferable surface layer of the present invention laminated on the heat-meltable colorant layer of the present invention is a layer that does not substantially contain a colorant and is melted by heating and transferred to the transfer paper during printing. Often, the main component is a heat-melting substance (especially a low-melting substance).

The low melting point substance can be selected from the low melting point substances listed for the coloring material layer. The low melting point substance may be the same as or different from the low melting point substance of the coloring material layer. Alternatively, it may be a combination of the hard wax and soft wax described in the description of the coloring material layer. Furthermore, the thermally transferable surface layer may contain the softener and other components or additives. However, the content of the other components or additives is preferably less than 50% by weight.

The thickness of the thermally transferable surface layer is 3 pm or less, especially 0,01~
January intestines are preferred.

The support used in the thermal transfer recording medium of the present invention preferably has heat-resistant strength, high dimensional stability, and high surface smoothness. Examples of materials include papers such as plain paper, condenser paper, laminated paper, coated paper, resin films such as polyethylene, polyethylene terephthalate, polystyrene, polypropylene, polyimide, paper-resin film composites, aluminum foil, etc. Metal sheets and the like are preferably used. The thickness of the support is generally 60 Ii, m or less, especially 2 to 2 m, in order to obtain good thermal conductivity.
Preferably, there are 20 tiles. Furthermore, in the thermal transfer recording medium of the present invention, the structure on the back side of the support may be optional, and a backing layer such as an anti-sticking layer may be provided.

Coating methods suitable for applying the heat-melting coloring material layer and the heat-transferable surface layer onto a support by solvent coating, hot melt coating, etc. are known in the art, and these techniques are also used in the present invention. be able to. For example, the heat-melting color material layer and the heat-transferable surface layer are formed by solvent coating the coating solution using any known technique such as a reverse roll coater method, an extrusion coater method, a gravure coater method, or a wire coater method. Can be painted.

The thermal transfer recording medium of the present invention may also include other constituent layers such as an undercoat layer. That is, for example, examples of the subbing layer include silicone resin, melamine resin, polyvinyl acetal resin, polyethylene, polyvinyl chloride, polyvinylidene chloride, fluororesin, etc., and the coating of the subbing layer is similar to the coating of the coloring material layer. It can be done in advance.

The thermal transfer recording medium of the present invention may contain highly thermally conductive fine powder in its constituent layers and/or in its support. The high thermal conductivity fine powder has a higher thermal conductivity than the above-mentioned softener (for example, thermal conductivity of 6, OX+o-' to 25.
0XIo" cal/sec * ctle °C) and has a high melting point. Many metals such as aluminum and copper can be used, and oxides such as tin oxide, aluminum oxide, and magnesium oxide, titanium nitride, etc. Nitrides of can also be used.

The high thermal conductivity fine powder of the present invention has a particle size of 3 or less,
More preferably 1#1. -The following is better.

[Effect of the Invention 1 According to the present invention, in a heat-sensitive transfer recording medium having a heat-melting coloring material layer on a support, the heat-melting coloring material layer contains a high-boiling point solvent, and the heat-melting Since the structure has a thermally transferable surface layer on a coloring material layer, it is possible to provide a good dye transfer image even on plain paper with low surface smoothness without reducing the resolution, and it is possible to provide a good dye transfer image even on plain paper with low surface smoothness. This has the effect of suppressing the occurrence of background stains (fogging), which is difficult to avoid with thermal transfer recording media.

[Example] Examples are given below, but the embodiments of the present invention are not limited thereto. In addition, "1 copy" used below means "
Parts by weight.

Example 1 On a polyethylene terephthalate film with a thickness of 5.3#L, a heat-melting coloring material layer coating liquid (A) having the following composition was applied using a wire bar so that the dry film thickness was 4W11, A coloring material layer was formed.

Carbon black 10 parts Microcrystalline wax (Micro UHF manufactured by BARECO) 20 parts Montan wax (manufactured by Kato Yoko Co., Ltd.) 20 parts Ethylene-ethyl acrylate resin (NUC knee 13070 manufactured by Nippon Unicar Co., Ltd.) 2 parts Dioctyl phthalate 4 parts Toluene 120 parts The following wax mixture (8) for a heat transferable surface layer,
The coating was applied so that the dry film thickness was 2 liters to obtain a thermal transfer recording medium sample (2) of the present invention.

Montan wax (Hoechst wax NE, manufactured by Hoechst) 20 parts polyethylene glycol (polyethylene glycol 5ooo
, manufactured by Wako Tsumugi Pharmaceutical Co., Ltd.) 2 parts Isopar (Isopar G.

(manufactured by Esso Oil Co., Ltd.) 200 parts For comparison, 5 parts of the above heat-melting coloring material layer coating solution (A)
．． A comparative heat-sensitive transfer recording medium sample was obtained by coating a polyethylene terephthalate film with a thickness of 3 using a wire bar so that the dry film thickness was Bμ.

Furthermore, using a coloring material layer coating solution obtained by removing dioctyl phthalate from the heat-melting coloring material layer coating solution (A), a wire bar was used to coat a polyethylene terephthalate film with a thickness of 5.3 μm to a dry film thickness of 4 μm. After applying the wax mixture (B) for the heat transferable surface layer, the dry film thickness is 2w.
Comparative thermal transfer recording medium sample ■
I got it.

Thermal transfer recording medium sample I [, X
Tests were carried out as follows for (1) and (2).

High sensitivity thermal printer (heating element density 8dot/-
Prototype machine equipped with the first thin-film line thermal head)
When the applied power per heating element is 0. Recording was performed by applying energy at θW for an application time of 2 milliseconds.

The transfer paper is pound paper (Beck smoothness 12sec)
etc. were used. Observation was made using a 25x magnifying glass, and the results were evaluated for resolution, background smudge (fog), and transferability using the following methods.

(Resolution) Beck smoothing 11 [550 sec, full fab on plain paper]
/ ) was printed and the printed portion was observed with a 25x magnifying glass.

As a result, the printed characters of sample (2) were crushed and unclear, and although sample (2) was better than sample (2), white spots were observed in the thin line areas. On the other hand, with sample ■, a clear print with no white spots or smearing was obtained. I observed it.

As a result, sample (1) had significant scumming over the entire surface. Samples ■ and ■ had almost no background stains.

(Transferability) Solid black printing is performed on plain paper with Beck smoothness of 12 seconds.
Optical reflection density was measured. As a result, sample ■ is 1.4
The sample ■ is 1. 1, and sample ■ was 0.8.

Comprehensively considering the above evaluation items, it can be seen that Sample LD of the present invention is extremely superior to Comparative Samples ■ and ■.

Patent applicant: Konishiroku Photo Industry Co., Ltd. Representative Patent Attorney Nobuaki Sakaguchi

Claims (1)

[Claims] In the li8 thermal transfer recording medium having a heat-melt coloring material layer on a support, the heat-melting coloring material layer contains a high boiling point solvent, and a heat-melting surface layer is provided on the heat-melting coloring material layer. A thermal transfer recording medium comprising: