JPH0415116B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a thermal transfer recording medium.
The present invention relates to a thermal transfer recording medium capable of obtaining a dye transfer image with no gloss.

[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. 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 colorant layer coated on the support. There is.

Dye transfer images (printed images) obtained from such conventional thermal transfer recording media have extremely smooth and glossy surfaces, which causes significant eye strain when the records need to be read for a long time. Additionally, there is a drawback that the dye transfer image cannot be seen depending on the condition of the light source. In this regard, JP-A-56-164891 proposes mixing a matting agent into the coloring material layer. However, according to this technology, compared to a thermal transfer recording medium that has a coloring material layer that does not contain a matting agent, the thickness of the coloring material layer must be increased in order to obtain a dye transfer image of the same density. Therefore, there is a drawback that the transfer sensitivity is lowered.

[Object of the Invention] An object of the present invention is to provide a thermal transfer recording medium capable of obtaining a matte dye transfer image without causing a decrease in sensitivity during thermal transfer.

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 heat-sensitive transfer recording medium having a heat-sensitive transferable coloring material layer on a support, the coloring material layer is composed of a polar polymer compound and a non-polar polymer compound. It has been discovered that the above object can be achieved by containing the following, leading to the present invention.

[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, and the coloring material layer contains at least one polar polymer compound and one nonpolar polymer compound.

The polar polymer compound used in the present invention preferably has a solubility parameter in the range of 10 to 15, more preferably 10 to 13, particularly preferably 10 to 12. If the solubility parameter is less than 10, it will be compatible with the non-polar polymer compound, making it impossible to achieve the purpose of the present invention. On the other hand, if the solubility parameter exceeds 15, it will be difficult to apply a uniform coloring layer. be.

In the present invention, the solubility parameter is written by Kozo Shinoda, "Revised and Expanded Solution and Solubility" [May 10, 1972]
Based on the definition described in Chapter 7 (pages 95 to 108) of the Japanese publication, Maruzen Co., Ltd.

Specific examples of the polar polymer compound used in the present invention include epoxy resin, acrylic resin, polyvinyl butyral resin, polyvinyl formal resin, polyvinyl acetate, alcohol-soluble rosin resin, cellulose acetate, ethyl cellulose, phenolic resin, polyester resin, Examples include melamine resin, cellulose acetate butyrate, polyurethane resin, and preferably ethyl cellulose, cellulose acetate butyrate, polyester resin, and the like.

The nonpolar polymer compound preferably used in the present invention has a solubility parameter of 9 to 6 or less, more preferably 9 to 7, particularly preferably 9 to 8. If the solubility parameter exceeds 9, the polar polymer compound cannot be dissolved and the object of the present invention cannot be achieved.

Specific examples of the non-polar polymer compound used in the present invention include polyethylene, petroleum resin, isoprene, terpene resin, polypropylene, ester gum, cyclopentadiene resin, etc., and preferably terpene resin, petroleum resin, cyclopentadiene resin, etc. Mention may be made of pentadiene resins.

The coloring material layer of the present invention contains one or more heat-melting substances. As this heat-fusible substance, conventionally known heat-fusible substances can be used without any particular restrictions.

The thermofusible substance preferably used in the present invention is
Softening point (measured by ring and ball method) or melting point (Yanagimoto
Measured value by MPJ-2 type) is 120℃ or less,
Particularly preferred are those having a melting point of 50 to 120°C.

Specific examples of thermofusible substances preferably used in the present invention include paraffin waxes such as paraffin wax and micro wax, natural waxes such as beeswax, carnauba wax, and wood wax, and Hoechst wax. Ester waxes, higher fatty acids such as stearic acid, palmitic acid, behenic acid, myristic acid, 1,20-eicosandioic acid, higher alcohols such as stearyl alcohol and palmityl alcohol, stearamide,
Higher amides such as oleamide and palmityroamide, butyl stearate, ethyl palmitate,
Examples include esters such as myristyl stearate.

The color material layer of the present invention contains at least one colorant. As the coloring agent, various dyes or pigments that have been widely used in the art can be used without any particular restrictions. For example, a substance that can be dissolved or dispersed in the binder in the colorant layer when melted, has a color, and is solid or semi-solid at room temperature may be used as the colorant, and various pigments known in the art may be used as the colorant. can be used. Specifically, the following can be mentioned. In other words, the yellow pigment is Kayalon Polyester Light Yellow 5G.
-S (Nippon Kayaku), Oil Yellow S-7 (white clay),
Eisenspiron GRH Special (Hodogaya), Sumiplast Yellow FG (Sumitomo), Eisenspiron Yellow GRH (Hodogaya), etc. are preferably used. Red pigments include Diaceriton Fastred R (Mitsubishi Kasei), Dianics Brilliant Red BS-E (Mitsubishi Kasei), Sumiplast Stretch FB (Sumitomo), Sumiplast Stret HFG (Sumitomo),
Kayalon Polyester Pink RCL-E (Nippon Kayaku), Eisen Spiron Red GEH Special (Hodogaya), etc. are preferably used. Blue pigments include Diaceritone Fast Brilliant Blue R (Mitsubishi Kasei) and Dianics Blue EB-E.
(Mitsubishi Kasei), Kayalon Polyester Blue B-
SF Conch (Nippon Kayaku), Sumiplast Blue 3R
(Sumitomo), Sumiplast Blue G (Sumitomo), etc. are preferably used. In addition, as yellow pigments, Hansa Yellow 3G, Tartrazine Lake, etc. are used.
As a red pigment, brilliant carmine FB-
Piure (Sanyo pigment), brilliant carmine 6B
(Sanyo Shiki), Alizarin Lake, etc. are used. As blue pigments, Cerulean Blue, Sumikaprint Cyanine Blue GN-O (Sumitomo), Phthalocyanine Blue, etc. are used. As black pigments, Carbon Black, Oil Black, etc. are used. used. In addition, metal particles or metal oxides may also be used.

The composition ratio of the coloring material layer of the present invention is 50 to 50% of the hot melt composite material.
90% (weight%, same hereinafter), polar polymer compound
2.5-25%, non-polar polymer compound 2.5-25%, and colorant 5-30%, and the composition ratio of polar polymer compound and non-polar polymer compound is 1:10-10.
The ratio may be 10:1, preferably in the range of 2:8 to 8:2.

The color material layer of the present invention may contain various additives in addition to the above components. For example, examples of the thermally conductive substance include metals with good thermal conductivity such as aluminum, copper, and zinc. Such a thermally conductive substance promotes the heat conduction effect of melting, softening, or sublimating the coloring material layer by heat. Furthermore, vegetable oils such as castor oil, linseed oil, and olive oil, animal oils such as whale oil, and mineral oils may be suitably used as softeners.

Coating methods suitable for coating a coloring material layer on a support by solvent coating, hot melt coating, etc. are known in the art, and these techniques can also be used in the present invention. For example, the coating solution of the present invention can be solvent coated using any known technique such as a reverse roll coater method, an extrusion coater method, a gravure coater method, or a wire bar coating method, and then the solvent can be removed to form a coating of 15μ or less. A color material layer can be applied.

Further, the thermal transfer recording medium of the present invention has at least one coloring material layer of the present invention, and in addition,
It may have other constituent layers such as a subbing layer, an intermediate layer, or an overcoat layer. That is, for example, examples of the undercoat layer include silicone resin, melamine resin, polyvinacetal resin, polyethylene, polyvinyl chloride, polyvinylidene chloride, fluorine resin, etc. This can be done prior to application.

Note that the support used as a base material for the thermal transfer recording medium of the present invention is preferably a support that 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 10 seconds or more in a smoothness test using a Beck testing machine (JIS P 8119).
When the time is 300 seconds or more, images with better transfer rate and reproducibility can be obtained. Examples of materials include:
Paper such as plain paper, condenser paper, laminated paper, coated paper, resin films such as polyester, polycarbonate, polyethylene, polyethylene terephthalate, polystyrene, polypropylene, polyimide, etc., paper-resin film composites, metal sheets such as aluminum foil, etc. etc. are all suitably used. The thickness of the support is preferably about 60 microns or less, particularly 2 to 20 microns, in order to obtain good thermal conductivity. Furthermore, in the thermal transfer recording medium of the present invention, the structure of the back side of the support is arbitrary.

[Effects of the Invention] According to the present invention, since the coloring material layer contains a polar polymer compound and a non-polar polymer compound, the above-mentioned object of the present invention can be achieved, and even when reading for a long time, it is easy to read. It does not make you tired, and because it is highly sensitive, high-speed recording (printing) is also possible. The reason for this is not necessarily clear, but the action of the polar polymer compound and the non-polar polymer compound causes the colorant layer to become uneven, resulting in a dye transfer image with an uneven surface. ,I think that the.

[Example] Examples are given below, but the embodiments of the present invention are not limited thereto.

Example 1 Parafine wax (mp62-64°C) 3g, carnauba wax 3g, Quinton D200 (synthetic terpene resin, manufactured by Nippon Zeon Co., Ltd.) (solubility parameter
8.3) Dissolve 1g in 60ml of toluene by heating,
Prepare the solution. On the other hand, dissolve 0.5 g of ethyl cellulose (40 cps) (dissolution parameter 10.3) in 20 ml of 2-propanol to prepare a solution. Disperse 10 g of carbon black (RAVEN1250, manufactured by Columbia Carbon) in 100 ml of 2-butanone using a sand mill to prepare a dispersion.

60ml of the above solution, 20ml of solution and 10ml of dispersion
ml were mixed with stirring at 50°C to obtain a coating solution.

This coating solution was coated on a 5.4μ polyethylene terephthalate film support with a wire bar while keeping it warm, and after drying at 80°C, a thermal transfer recording medium sample of the present invention having a colorant layer with a film thickness of 3.1μ was obtained. .
This sample was printed on plain paper using a high-sensitivity thermal printer (a prototype equipped with a thin-film line thermal head with a heating element density of 8 dots/mm). As a result, a clear dye transfer image with no gloss and excellent tamper resistance and storage stability was obtained.
The glossiness of this dye transfer image was measured at an angle of 75° C. using the method described in JIS Z 8741 and found to be 6.9%.

Comparative Example 1 Quinton D200 was used instead of the solution of Example 1.
A film thickness of 3.1μ was obtained using the same recipe and method as in Example 1, except that a solution of 0.5g of
A comparative thermal transfer recording medium sample having a coloring material layer was obtained. This sample was printed on the same plain paper using the same thermal printer as in Example 1, but only a glossy and difficult to see printed image was obtained. The glossiness was measured using the same measuring method as in Example 1 and was found to be 25%.

Claims (1)

[Claims] 1. A heat-sensitive transfer recording medium having a heat-sensitive transferable coloring material layer on a support, wherein the coloring material layer contains a polar polymer compound and a non-polar polymer compound.