JPH0257798B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to a thermal transfer recording medium.
It has high transfer sensitivity and can be printed with low energy.
It also suppresses background stains (fogging) on recording sheets such as plain paper, and has sufficient film strength to prevent peeling and transfer even when folded or artificially wrinkled. The present invention relates to a thermal transfer recording medium in which no layer defects are observed. [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 by a thermal printer, a thermal facsimile, or the like. This thermal transfer recording medium has at least one coloring material layer on a support, and the coloring material layer includes, for example, a layer containing a coloring agent made of a dye such as a pigment and a heat-fusible substance. etc. are known. As the heat-melting substance, a low-melting point substance such as wax or wax is used.
In addition, films with excellent surface smoothness and dimensional stability are used as the support in order to obtain good reproducibility of the dye transfer image obtained from the color material layer coated on the support. There is. When using a thermal printer or thermal facsimile with a thermal head or thermal pen to record a dye transfer image on plain paper using such a thermal transfer recording medium, it is desirable to print with low energy. However, the transfer sensitivity of conventional thermal transfer recording media was low and insufficient.
Furthermore, there was also the drawback that background stains (fogging) occurred on the recording sheet. As one method of increasing transfer sensitivity, a technique for improving the thermal conductivity of a coloring material layer is disclosed in Japanese Patent Laid-Open No. 75894/1983. The invention is a technology for containing a powdered thermally conductive substance in a coloring material layer, and since it requires the use of additives, the coloring material layer may become thick depending on the type of additive. There were cases where the resolution deteriorated. Furthermore, there was also the drawback that background stains (fogging) occurred on the recording sheet. The inventors of the present invention have found that these drawbacks can be overcome by incorporating silicone wax into the coloring material layer, and have previously proposed this in Japanese Patent Application No. 58-204709. As a result of continuing research on the previously proposed invention, the present inventor found that the film strength was insufficient, and when bent or artificially wrinkled, the film may peel off or the transfer layer may be missing. I found out. [Object of the Invention] Therefore, the object of the present invention is to provide a method that has high transfer sensitivity, can print with low energy, and can suppress the occurrence of background stains (fog) on a recording sheet such as plain paper, and further, It is an object of the present invention to provide a heat-sensitive transfer recording medium which has sufficient film strength and does not exhibit film peeling or loss of a transfer layer even when bent or artificially wrinkled. Other objects of the invention will become apparent from the following description of the specification. [Summary of the Invention] As a result of intensive research, the present inventor has discovered that in a thermal transfer recording medium having a heat-sensitive transferable coloring material layer on a support, the coloring material layer is

[Formula] Furthermore

[Structure of the invention]

The present invention will be explained in more detail below. The thermal transfer recording medium of the present invention has at least one coloring material layer on a support. The coloring material layer contains at least one each of the silicone wax of the present invention and the rosin polymer of the present invention. The silicone wax of the present invention is solid at room temperature (25°C) (therefore, silicone oil that is liquid at room temperature is excluded), and its melting point (value measured by Yanagimoto MPJ-2 model) is
30℃ or higher, preferably 35℃ or higher and 100℃ or lower,
Particularly preferably, the temperature is 40°C or higher and 90°C or lower. The silicone wax of the present invention is preferably represented by the following general formula (1). General formula (1) In the formula, Me represents a methyl group, and X is -
CnH ₂ nR ₈ (R ₈ represents a hydrogen atom or a substituent such as a linear or branched alkyl group or an aralkyl group), -O-CnH ₂ nR ₈ (R ₈ is the same as R ₈ above.) , -O-CO-CnH ₂ nR ₈ (R ₈ is the same as R ₈ above), -CnH ₂ nY (Y represents an organic group such as -OH or -SH), CnH ₂ nCOOR ₉ (R ₉ represents an alkyl group or other organic group _having 1 to 40 carbon atoms) or ( _CH2 )aO( _C2H4O )b( _C3H6O ) _cR7 ( _R7 represents _an alkyl group, a, b, c represent integers greater than or equal to 0). Further, all n represents an integer of 0 or more. α, β...σ each represents an integer of 0 or more. However, α, β...σ are not all 0 at the same time. If everything other than αβ, such as σ, is 0, the larger the values of α and β, and the larger β is compared to α, the higher the melting point will be.Furthermore, the larger the molecular weight of the substituent X, the higher the melting point. The values of α and β can be selected as necessary in consideration of the molecular weight of the group X, and both α and β are preferably 0 or more and 1000 or less, more preferably 500 or less, and particularly preferably 100 or less. The representative example shown by the above general formula specifically explains a part of the silicone wax of the present invention, and is not limited thereto. For example, the silicone wax of the present invention may have a multidimensional bonding structure (varnish structure) as described below. Of course, even when it has a multidimensional bond structure (varnish structure), it may be substituted with an organic group. Specific examples having such a varnish structure include KR216, KR220, and X-22 manufactured by Shin-Etsu Chemical Co., Ltd.
-801 etc. Specific examples of the silicone wax of the present invention are listed below. [In the above formula, α, β, a, b, and c are integers greater than or equal to 0, and α and β are never 0 at the same time. R ₇ represents an alkyl group, and R ₉ represents an alkyl group having 1 to 40 carbon atoms or other organic group. Also Me
indicates a methyl group. ] In addition to the above silicone waxes, the silicone waxes of the present invention include fluorine-modified silicone waxes having trifluoroalkyl groups in the molecule, particularly hydrophilic silicone waxes with hydrophilic groups introduced, higher fatty acid-modified silicone waxes, and carnauba-modified silicone waxes. Typical examples include silicone wax, carboxyl-modified silicone wax, amide-modified silicone wax, etc., but they are not limited thereto. Furthermore, the substituent part or the above R ₁ and/or
_A reactive group (e.g., -OH, _-NH2 ,
It may be a compound into which an unsaturated bond-containing group, an epoxy-derived group is introduced, or a compound formed after these are reacted with another compound. The silicone wax of the present invention is solid at room temperature (25°C), may contain multiple types of substituents, and can freely change the substitution ratio until all methyl groups are substituted. . These substituents can be preferably designed to maximize compatibility with other coexisting waxes or resin components containing the rosin polymer of the present invention. The silicone wax of the present invention may be used alone or in combination of two or more. It may also be used in combination with other heat-fusible substances.
The silicone wax of the present invention is effective even if it is contained in a few percent (by weight, the same applies hereinafter) in the coloring material layer, but preferably it accounts for 10 to 100% of the heat-fusible substance contained in the coloring material layer. is the silicone wax of the present invention, and preferably 30% or more, particularly 50% or more of the silicone wax of the present invention is the silicone wax of the present invention. The heat-fusible substances that may be used with the silicone wax of the present invention include conventionally known heat-fusible substances without particular limitation, but specific examples of the heat-fusible substances preferably used in the present invention include: teeth,
For example, paraffin wax, micro wax,
Paraffin waxes such as polyethylene wax, natural waxes such as beeswax, carnauba wax, and wood wax, ester waxes such as Hoechst wax, stearic acid, palmitic acid, behenic acid, myristic acid, 1,20- Examples include higher fatty acids such as eicosanedioic acid, higher alcohols such as stearyl alcohol and palmityl alcohol, higher amides such as stearamide, oleamide and palmitylamide, and esters such as butyl stearate, ethyl palmitate and myristyl stearate. be able to. The coloring material layer of the present invention includes a petroleum resin obtained by copolymerizing a fraction having 5 or more carbon atoms in a petroleum naphtha decomposition product, a coumaron indene resin, a terpene resin, a phenol resin, a xylene resin, a toluene resin, and an ester. It contains at least one resin selected from gum, rosin, hydrogenated rosin, modified rosin, aliphatic hydrocarbon resin, and alicyclic hydrocarbon resin. The rosin polymer of the present invention can also be obtained from commercial products. For example, ester gums include Ester EG-H manufactured by Tokushima Seyu Co., Ltd. and S-S-1 manufactured by Arakawa Chemical Co., Ltd.
80, EK-100, EK-1001, HP, HD, etc.In addition to commercially available natural rosins such as Chinese rosin, there are polymerized rosin Polypail manufactured by Arakawa Chemical Co., Ltd., and hydrogenated rosin. Examples include Hyperel manufactured by Arakawa Chemical Co., Ltd., and examples of aliphatic hydrocarbon resins include Quinton 100 series resins such as Quinton B-170, N-180, D-100, and D-200 manufactured by Zeon Corporation. Arapol manufactured by Arakawa Chemical Co., Ltd.
1070, 1090, etc., and alicyclic hydrocarbon resins include Quinton 1300 series manufactured by Nippon Zeon Co., Ltd.
Quinton 1000 series resins such as the 1500 series and 1799 series, and Arakawa Chemical's Alcon P70, P80, and
There are P90 etc. In the present invention, ester gums preferably used include hydrogenated rosin esters, glycerin esters of modified rosins, glycerin esters of special rosins, pentaerythritol esters of hydrogenated rosins, and ethylene glycol esters of hydrogenated rosins. In the present invention, one or a combination of two or more of these rosin polymers may be used. The coloring agent to be contained in the coloring material layer of the present invention may be appropriately selected from conventionally known pigments, for example, direct dyes, acid dyes, basic dyes, disperse dyes, oil-soluble dyes, etc. . The pigment used in the color material layer of the present invention may be any pigment that can be transferred (transferred) together with the heat-fusible substance containing the silicone wax of the present invention, so that it may be a pigment in addition to the above. Although the composition ratio of the coloring material layer of the present invention is not limited,
For the total amount of color material layer 100 parts (parts by weight, the same applies hereinafter),
A thermofusible substance containing the silicone wax of the present invention
50 to 90 parts, the coloring agent is 5 to 20 parts, and the rosin polymer of the present invention is 1 to 100 parts, preferably 3 to 100 parts, based on the heat-melting material containing the silicone wax of the present invention.
50 parts, more preferably 5 to 30 parts. The color material layer of the present invention may contain various additives in addition to the above components. 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 as softeners. The support used as a base material for the thermal transfer recording medium of the present invention preferably has heat-resistant strength, high dimensional stability, and high surface smoothness. Heat resistance strength requires strength and dimensional stability to maintain the toughness of the support without becoming softened or plasticized by the heating temperature of a heat source such as a thermal head, and surface smoothness requires heat melting on the support. It is desired that the layer containing a sexual substance has sufficient smoothness to exhibit a good transfer rate. The smoothness should be 100sec or more in the smoothness test using a Beck testing machine (JISP8119), and 300sec or more.
If it is above, an image with better transfer rate and reproducibility can be obtained. Materials include, for example, papers such as plain paper, condenser paper, laminated paper, and coated paper, or polyethylene, polyethylene terephthalate, polystyrene, polypropylene,
Resin films such as polyimide, paper-resin film composites, metal sheets such as aluminum foil, etc. are all suitably used. The thickness of the support is usually about 60 μm or less, especially 2 to 2 μm, in order to obtain good thermal conductivity.
Preferably, it is 20 μm. In the thermal transfer recording medium of the present invention, the structure of the back side of the support is arbitrary. In the thermal transfer recording medium of the present invention, techniques suitable for applying the coloring material layer to a support such as a polymer film are known in the art, and these techniques can also be used in the present invention. For example, the coloring material layer is a layer formed by hot melt coating the composition or by solvent coating a coating solution prepared by dissolving or dispersing the composition in an appropriate solvent. As a method for applying the coloring material layer of the present invention, any known technique can be employed, such as a reverse roll coater method, an extrusion coater method, a gravure coater method, and a wire bar coating method. The color material layer of the present invention has a thickness of 15 μm or less, preferably 2 μm.
It is sufficient if it is set to ~8 μm. [Effects of the Invention] According to the present invention, in a heat-sensitive transfer recording medium having a heat-sensitive transferable coloring material layer on a support, the coloring material layer is selected from silicone wax that is solid at room temperature and the rosin polymer of the present invention. Since it contains at least one resin that can Even in this case, it is possible to suppress the occurrence of background stains (fog) on recording sheets such as plain paper, and it also has sufficient film strength to prevent bending or artificial wrinkles. No peeling of the membrane or loss of the transfer layer is observed. [Example] Examples will be given below, but the embodiments of the present invention are not limited thereto. Note that "parts" used below indicate "parts by weight." Example 1 Alcohol-modified silicone wax (X-22-801 manufactured by Shin-Etsu Chemical Co., Ltd.) 10 parts Microcrystalline wax (melting point 69°C) 1.5 parts Ester gum (Ester gum S- manufactured by Arakawa Chemical Co., Ltd.)
80) (Softening point: 70-80°C) 1.5 parts Carbon black 2 parts Toluene 50 parts The above composition was dispersed in a thermal ball mill for 24 hours to obtain a coating solution for a coloring material layer. This coating liquid was applied onto a polyethylene terephthalate film support having a thickness of 5.4 μm using a wire bar to form a coloring material layer having a thickness of 3.5 μm after drying, thereby obtaining a thermal transfer recording medium sample. This thermal transfer recording medium sample was printed using a thermal printer (a prototype machine equipped with a thin-film line thermal head with a heating element density of 8 dots/mm), and the applied energy was changed from 0 to 0.6 mJ/dot by 0.03 mJ/dot.
Printing was performed on plain paper at varying intervals, and the light reflection density of the printed dye transfer image was measured using a reflection densitometer (manufactured by Konishiroku Photo Industry Co., Ltd.). maximum optical reflection density
The applied energy required to obtain a 0.9x dye transfer image was defined as the transfer sensitivity. As a result, the applied energy required to obtain a dye transfer image with a density of 1.4 is:
0.36 mJ/dot (obtained by plotting on the graph).
same as below. ). No occurrence of background stains (fogging) was observed. Furthermore, the film strength is sufficient,
Even when folded or artificially wrinkled, almost no peeling of the film or loss of the transfer layer was observed. Example 2 In Example 1, olefin-modified silicone wax (X-22- manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of alcohol-modified silicone wax in the colorant layer composition.
A thermal transfer recording medium sample was obtained in exactly the same manner except that rosin (gum rosin manufactured by Arakawa Chemical Co., Ltd.) was used in place of 1.5 parts of ester gum. When printing was attempted on this sample using the same method as the sample, a dye transfer image with a density of 1.4 was obtained with an applied energy of 0.39 mJ/dot. Further, no occurrence of background stains (fogging) was observed. Furthermore, the film had sufficient strength. Example 3 In Example 1, aliphatic hydrogen resin (Quinton manufactured by Nippon Zeon Co., Ltd.) was used instead of 1.5 parts of ester gum.
A thermal transfer recording medium sample was obtained in exactly the same manner except that 3 parts of N180) were used. When printing was attempted on this sample using the same method as the sample, a dye transfer image with a density of 1.4 was obtained with an applied energy of 0.38 mJ/dot. Further, no occurrence of background stains (fogging) was observed. Also, the film had good strength. Comparative Example 1 In Example 1, when microcrystalline wax (melting point 69°C) was used in place of the ester gum in the coloring material layer composition, the sensitivity and background staining were almost the same, but When the transfer sheet was folded or wrinkled artificially, peeling of the film or loss of the transfer layer occurred. Comparative Example 2 In Example 1, when low molecular weight polyethylene (Sanwax 171 manufactured by Sanyo Chemical Co., Ltd.) was used in place of the ester gum in the colorant layer composition, the film strength was not sufficient. Comparative Example 3 In Example 1, when polystyrene (manufactured by Sanwa Kagaku Co., Ltd., melting point: 69°C) was used in place of the ester gum in the colorant layer composition, the film strength was not sufficient. Comparative Example 4 A thermal transfer recording medium sample was obtained in exactly the same manner as in Example 1, except that paraffin wax (melting point 50°C) was used in place of the alcohol-modified silicone wax in the colorant layer composition. When printing was attempted on this sample using the same method as the sample, only a dye transfer image with a density of 0.27 was obtained with an applied energy of 0.36 mJ/dot. Furthermore, when the applied energy was increased to obtain a dye transfer image with a density of 1.4, the film strength was relatively strong, but a decrease in resolution was observed, and at the same time, background smear (fog) was observed. Comparative Example 5 Similar evaluations were conducted using the alcohol-modified silicone wax of Example 1 as unmodified dimethylpolysiloxane. A sufficient concentration (concentration 1.4) could not be obtained at 0.36 mJ/dot.

Claims (1)

[Scope of Claims] 1. A heat-sensitive transfer recording medium having a heat-sensitive transferable coloring material layer on a support, wherein the coloring material layer has a bonding group represented by [formula] and further has a bonding group represented by [formula] [provided that , Me represents a methyl group, and at least one of R ₁ and R ₂ represents an organic group other than the methyl group. ] Petroleum resins, coumaron indene resins, terpene resins, phenolic resins, xylene resins obtained by copolymerizing silicone wax that is solid at room temperature (25°C) and fractions of carbon atoms of 5 or more from petroleum naphtha decomposition products. , toluene resin, ester gum, rosin,
A thermal transfer recording medium characterized by containing at least one resin selected from hydrogenated rosin, modified rosin, aliphatic hydrocarbon resin, and alicyclic hydrocarbon resin.