JP2009202392A - Thermosensitive transfer recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermosensitive transfer recording medium, which develops neither slurring of images nor breakage of a sheet at thermal transferring and, at the same time, which is equipped with enough sensitivity. <P>SOLUTION: In the thermosensitive transfer recording medium, one side of a base material film 1 of which is provided with thermosensitive transfer colorant layers 2Y, 2M and 2C, and the other side of the base material of which is provided with a back-coating layer 4, the tear strength in the subscanning direction by the Trouser tear method according to JIS K7128-1 is ≥2.0(N/mm) and, at the same time, the tear strength in the main scanning direction by the right-angled tear method according to JIS K7128-3 is 25(N/mm). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat-sensitive transfer recording medium using a sublimable dye or a heat-meltable pigment, and more particularly to a heat-sensitive transfer recording medium in which breakage of a heat-sensitive transfer recording medium sheet or printed image hardly occurs during heat transfer.

  In thermal transfer, in a printer, a color material such as a dye of a thermal transfer recording medium is transferred to a transfer medium by heating and pressing with a thermal head or the like to form an image. As heat-sensitive transfer recording media, those using sublimation dyes or heat-melting transfer dyes as color materials have been particularly widespread in recent years because they have excellent gradation expression. The images obtained by these methods are close to silver halide photographs in terms of smoothness and density of gradation, and unlike silver salt photographs, images can be processed and printed digitally, so the output of digital cameras and computer graphics Conveniently used for output images and print proofing.

  For example, a plastic film such as polyethylene terephthalate film is often used as the base film of the thermal transfer sheet. However, the following problems arise when using a plastic film. That is, a high temperature of 300 ° C. to 400 ° C. is locally applied from the thermal head to the thermal transfer recording medium during transfer, and the thermal transfer recording medium is deformed by the heat and the stress applied to the thermal transfer recording medium. An image shift may occur in an image. Or, in extreme cases, the film may be broken from minute scratches formed at the end during printing.

  Although it is conceivable to use a thick substrate film as a means for solving such a problem, in this case, the sensitivity of thermal transfer recording is lowered and lacks practicality. In addition, it is widely practiced to provide a heat-slipable backcoat layer on the side in contact with the thermal head, but even if this method is used, image misalignment or sheet breakage occurs, which is a fundamental solution. It was good.

  The present invention has been made in view of the above situation, and in a thermal transfer recording medium, the thermal transfer recording medium gives an image with sufficient sensitivity without causing image displacement or sheet breakage during thermal transfer. Is to provide.

  In order to achieve this object, the invention of claim 1 is a thermal transfer recording medium in which a thermal transfer color material layer is provided on one side of a base film and a backcoat layer is provided on the other side. The tear strength by the trouser tear method specified in JIS K7128-1 in the sub-scanning direction is 2.0 (N / mm) or more, and the tearing by the right-angled tear method specified in JIS K7128-3 in the main scanning direction A thermal transfer recording medium having a strength of 25 (N / mm) or more.

  According to a second aspect of the present invention, there is provided the thermal transfer recording medium according to the first aspect, wherein the shrinkage rate by heating at 150 ° C. for 30 minutes in the main scanning direction and the sub-scanning direction is less than 3%.

In a thermal transfer recording medium in which a thermal transfer color material layer used for thermal sublimation transfer recording or hot-melt transfer recording is provided on one side of the substrate film, and a backcoat layer is provided on the other side,
Right-angled tearing method defined in JIS K7128-3 in the main scanning direction while keeping the tear strength by the trouser tearing method defined in JIS K7128-1 in the sub-scanning direction in the thermal transfer medium at 2.0 (N / mm) or more. By keeping the tear strength by 25 or more (N / mm) and further by reducing the shrinkage ratio by heating at 150 ° C. for 30 minutes in the main scanning direction and the sub-scanning direction to less than 3%, image displacement or sheet It is possible to provide a thermal transfer recording medium that gives an image with sufficient sensitivity without causing breakage.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional explanatory view of a thermal transfer recording medium. In order to simplify the explanation, the following explanation will mainly focus on the case where the heat-sensitive transfer color material layer is a sublimation transfer layer for heat-sensitive sublimation transfer recording, and is necessary for the case where the heat-sensitive transfer color material layer is for heat-melt transfer recording. Touch as much as possible.

  The substrate film 1 according to the present invention supports the sublimation transfer layers 2Y, 2M, 2C (hereinafter referred to as sublimation transfer layer 2) and the transferable protective layer 3. The base film 1 is formed on the film base 11 and the easy adhesion formed thereon to prevent the sublimation transfer layer 2 itself from being transferred when the sublimation dye in the sublimation transfer layer 2 is transferred by the thermal head. It consists of layer 12.

  The film base 11 needs heat resistance that is not softened and deformed by heating with a thermal head. For this reason, a polyester film, specifically, a polyethylene terephthalate film or a polyethylene naphthalate film is desirable. In addition, a long film having a thickness of 1 to 20 μm is preferable from the viewpoint of thermal conductivity and strength. The easy-adhesion layer 12 is for firmly bonding the film base 11 and the sublimation transfer layer 2.

  As will be described later, since the sublimation transfer layer 2 contains polyvinyl acetal or the like as the main component of the binder, the easy-adhesion layer 12 is preferably a polyurethane resin composed of a reaction cured product of polyisocyanate and polyol. As the polyisocyanate, 2,4 tolylene diisocyanate, 2,6 tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, naphthalene diisocyanate, metaxylylene diisocyanate, vitolylene diisocyanate and the like can be used. Moreover, as a polyol, polyester polyol, polyether polyol, acrylic polyol, etc. can be used.

  Such a polyurethane resin is commercially available under the name of urethane paint or urethane adhesive. That is, it is a polyisocyanate such as Nippon Polyurethane Co., Ltd. Nisporan 3110, 3113, or 3115, and a polyol such as Nippon Polyurethane Co., Ltd. Coronate EH. The easy adhesion layer 12 can be applied and formed by a method such as roll coating, reverse coating, and gravure coating. In order to ensure thermal conductivity, it is necessary to form a thin film, for example, 5 μm or less is desirable. However, in order to maintain the adhesive force, it is desirable to have a thickness of 0.1 μm or more.

  The sublimation transfer layer 2 is formed by arranging three sublimation transfer layers of yellow (2Y), magenta (2M), and cyan (2C) side by side in the longitudinal direction of the ribbon in order to form a gradation color image.

  The sublimation transfer layer 2 is composed of a dye of each color and a binder. The dye is a so-called sublimation dye and is sometimes called a vaporizable dye or a heat-melt transfer dye. Usually a disperse dye or an oil-soluble dye. It is necessary to be able to transfer well under the heat generation conditions of the thermal head during recording, for example, an applied voltage of 5 to 50 V and an applied time of several ms. The exothermic temperature is usually 300 to 400 ° C.

Examples of the dye used for the yellow (Y) sublimation transfer layer 2Y include, for example, Kayacet Yellow AG, Kayakut Yellow TDN (manufactured by Nippon Kayaku Co., Ltd.), PTY52, Dianix Yellow 5R-E, Dian
ix Yellow F3G-E, Dianix Brilliant Yellow 5G-E (Mitsubishi Chemical Corporation), Plast Yellow 8040, DY 108 (Arimoto Chemical Co., Ltd.), Sumikaron Yellow EFG, Sumikaron Yellow E-4GL (For example, Sumitomo Chemical Co., Ltd.), FORON Brilliant Yellow S6GLPI (Sand) and the like.

  Examples of the dye used for the sublimation transfer layer 2M of magenta (M) include, for example, Kayacet Red 026, Kayacet Red 130, Kayacet Red B (manufactured by Nippon Kayaku Co., Ltd.), Oil Red DR-99, Oil Red DK-99. (Arimoto Chemical Co., Ltd.), Diacelliton Pink B (Mitsubishi Chemical Co., Ltd.), Sumikaron Red E-FBL (Sumitomo Chemical Co., Ltd.), Latyl Red B (du Pont), Sudan Red 7B (Manufactured by BASF), Resolin Red FB, Ceres Red 7B (manufactured by Bayer) and the like.

  Examples of the dye used for the cyan (C) sublimation transfer layer 2C include, for example, Kaylon Fast Blue FG, Kayacet Blue FR, Kayacet Blue 136, Kayacet Blye 906 (manufactured by Nippon Kayaku Co., Ltd.), Oil Blue 63 ( Arimoto Chemical), HSB9 (Mitsubishi Chemical), Disperse Blue # 1 (Sumitomo Chemical), Ceres Blue GN (Bayer), Durano Brilliant Blue 2G (ICI) Etc. can be illustrated.

  The binder fixes the sublimation dye to the base film 1, and it is necessary that the binder does not adhere to the image receiving member during transfer by the thermal head and does not transfer. For this reason, a resin whose main component is a crosslinked product of polyvinyl alcohol is desirable. For example, polyvinyl acetal and polyvinyl butyral. These resins having a molecular weight of 10,000 to 80,000 can be used. A small amount of other resin such as ethyl cellulose can be mixed to improve the permeation of the dye during transfer.

  In order to improve the thermal responsiveness of the sublimation transfer layer 2, it is desirable that the dye occupies 30 to 70% by weight in the components of the sublimation transfer layer 2. The sublimation transfer layer 2 can be formed by applying a gravure printing method by dissolving or dispersing a dye and a binder in an appropriate solvent. As the solvent, known solvents such as alcohols, ketones, and aromatics can be used. The sublimation transfer layer 2 may be provided with a dry film thickness of 0.5 to 5 μm according to the target image density. If the film thickness is insufficient with a single application, it may be overprinted many times.

  Further, if necessary, a heat transferable protective layer for protecting the image may be provided in the surface order with the dye layer. Examples of the resin used for the protective layer 32 include cellulose derivatives such as nitrocellulose, ethyl cellulose, and cellulose acetate propionate, styrene resins such as polystyrene and poly α-methylstyrene, and acrylic resins such as polymethyl methacrylate and polyethyl acrylate. Resin, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyvinyl acetal and other vinyl resins, polyester resin, polyamide resin, epoxy resin, polyurethane resin, petroleum resin, ionomer, ethylene acrylic Synthetic resins such as acid copolymer, ethylene-acrylic acid ester copolymer, rosin, rosin modified maleic acid resin, ester gum, polyisobutylene rubber, butyl rubber, styrene butadiene rubber, butadiene acrylonitrile Rugomu, polyamide resins, derivatives of natural resins and synthetic rubber polychlorinated olefins such like. The protective layer 32 can be formed of a composition composed of one or more of the above materials. In order to improve the peelability of the heat transferable protective layer 32, a release layer 31 made of a resin that is incompatible with the heat transferable protective layer may be provided as necessary.

  In addition, when the thermal transfer recording medium is wound, the sublimation transfer layer 2 and the thermal transferable protective layer 32 are prevented from adhering (blocking) to the opposite surface of the thermal transfer recording medium, and the base film 1 is attached to the thermal head. In order to prevent adhesion and hindering smooth running of the thermal transfer recording medium, it is desirable to provide the backcoat layer 4 on the surface opposite to the sublimation transfer layer of the base film 1.

  For the backcoat layer, it is desirable to use a silicone resin in order to ensure smooth running of the thermal transfer recording medium. For example, it is a silicone-modified resin obtained by condensing a silicone intermediate condensate having an alkoxy group (for example, methoxy group or ethoxy group) at the terminal with an alkyd resin, an epoxy resin, a polyester resin, an acrylic resin, or the like. Such a resin is commercially available from Shin-Etsu Chemical Co., Ltd. under the name KR218. Further, when the silicone oil is mixed and applied in the resin, or the silicone oil is applied on the silicone-modified resin layer to form a two-layer structure, the running property of the thermal transfer recording medium is improved. For example, dimethyl silicone oil, methylphenyl silicone oil, polyether-modified silicone oil and the like. The back coat layer 4 is preferably thin, and a thickness of 0.1 to 5 μm is sufficient. Application can be by gravure coating, roll coating, reverse coating, or the like.

  Note that the tear strength and heat shrinkage rate by the trouser tear method or the right angle tear method in the present invention are not measured values of the base film alone, but are provided with an easily adhesive layer, a sublimation transfer layer, a back coat layer, etc. In the heat-sensitive transfer recording medium.

  The tear strength by the trouser tear method was measured based on JIS K7128-1. The measurement is performed under the condition of 23 ° C., a slit having a depth of 75 mm is inserted in the center of the long side of a 150 mm × 50 mm test piece, and the long leg is attached to Tensilon (manufactured by Orientec Co., Ltd., RTC U-2023) and pulled. A test was conducted. The shape of the test piece is shown in FIG. The tear strength was calculated by dividing the average force required to tear the test piece in the longitudinal direction by the thickness of the test piece. The test speed was 200 mm / min, and 20 mm at the start of tearing and 5 mm before the end of tearing were excluded, and the average value of the tear strength of the remaining 50 mm was obtained. The specimen collection direction is the sub-scanning direction.

  The tear strength by the right angle tear method was measured based on JIS K7128-3. The measurement was performed under the condition of 23 ° C., and a test piece having a shape defined in JIS K7128-3 was cut out and a tensile test was performed with Tensilon (manufactured by Orientec Co., Ltd., RTC U-2023). The shape of the test piece is shown in FIG. The tear strength test speed was 200 mm / min, and the maximum load when the specimen was completely torn was divided by the thickness of the specimen. The specimen collection direction is the main scanning direction.

  In addition, the heat shrinkage rate is set on a plate laid with powdered kaolin preheated to a temperature of 150 ° C. with a 100 mm × 100 mm test piece, heated at 150 ° C. for 30 minutes in a clean oven, The change in the dimension in the sub-scanning direction is expressed as a percentage when the length of the original substrate is 100%.

The tear strength by the trouser tear method is preferably 2.0 (N / mm) or more, and the tear strength by the right angle tear method is preferably 25 (N / mm) or more. If the tearing strength by each tearing method is less than the above value, the thermal transfer recording medium may be broken or the image may be displaced during thermal transfer. The tear strength is more preferably 2.5 (N / mm) or more in the trouser tear method and 28 (N / mm) or more in the right angle tear method. Furthermore, it is desirable to keep the heat shrinkage rate in a range of less than 3% because it can further prevent sheet breakage and image displacement due to thermal deformation.

  Hereinafter, the present invention will be specifically described by way of examples of one embodiment.

<Example 1>
A polyethylene terephthalate film having a thickness of 4.5 μm was used as a film base, and an easy-adhesion layer was coated on the entire surface of one side by a gravure coating method. The easy-adhesion layer is formed by mixing 40 parts by weight of polyester polyol (Coronate EH, manufactured by Nippon Polyurethane Co., Ltd.) with 100 parts by weight of diphenylmethane diisocyanate (Nisporan 3110, manufactured by Nippon Polyurethane Co., Ltd.) and applying it immediately after mixing. did. The coating thickness is 1.0 μm in terms of dry film thickness.

  After the easy-adhesion layer was completely cured, each sublimation transfer layer of Y, M, and C was applied by gravure printing so that the dry film thickness was 1.5 μm. The ink composition of the sublimation transfer layer is as follows. The yellow ink layer is Kayace Yellow AG (manufactured by Nippon Kayaku Co., Ltd.), and the magenta ink layer is Kayace Red 026 (manufactured by Nippon Kayaku Co., Ltd.). The cyan ink layer is HSB9 (manufactured by Mitsubishi Chemical Corporation).

<Sublimation transfer ink composition>
Dye 10 parts by weight Polyvinyl butyral 9 parts by weight Ethyl cellulose 1 part by weight Isopropyl alcohol 30 parts by weight Methyl ethyl ketone 9 parts by weight Further, silicone (KP301 manufactured by Shin-Etsu Chemical Co., Ltd.) is used as a back coat layer on the surface on which the sublimation transfer layer is not provided. The thermal transfer recording medium of the present invention was obtained by coating at a rate of 0.5 g / m ² .

<Comparative Example 1>
Thermal transfer in the same manner as in Example 1 except that the base film was changed to a polyethylene terephthalate film (thickness 5.5 μm) that had been subjected to easy adhesion treatment with a mixed resin of acrylic resin and polyester resin in a dry film thickness of 0.1 μm. A recording medium was obtained.

  Table 1 shows the trouser tear strength, right-angled tear strength, and heat shrinkage ratio of the thermal transfer recording media prepared in Example 1 and Comparative Example 1.

  Each of the above thermal transfer recording media was printed on a commercially available image receiving paper using a commercially available sublimation transfer type printer to obtain an image transfer product, and the performance was compared.

  As a result, the thermal transfer recording medium prepared in Example 1 was able to obtain a good transfer product without breakage or image displacement of the thermal transfer recording medium. On the other hand, with the thermal transfer recording medium prepared in Comparative Example 1, the thermal transfer recording medium was not broken and a transfer product was obtained, but there was a slight shift in the image.

1 is a cross-sectional explanatory view of one embodiment of a thermal transfer recording medium of the present invention. It is the schematic of the test body used for the trouser tear test of a thermal transfer recording medium. It is the schematic of the test body used for the right-angle type tear test of a thermal transfer recording medium.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Base film 11 ... Film base 12 ... Easy-adhesion layer 2Y ... Sublimation transfer layer (yellow)
2M ... Sublimation transfer layer (magenta)
2C ... Sublimation transfer layer (cyan)
3 ... Protective layer 31 ... Release layer 32 ... Thermal transfer protective layer 4 ... Backcoat layer

Claims (2)

  A thermal transfer recording medium in which a thermal transfer color material layer is provided on one side of a base film and a backcoat layer is provided on the other side, and a trouser tear method defined in JIS K7128-1 in the sub-scanning direction The tear strength according to JIS K7128-3 in the main scanning direction is not less than 2.0 (N / mm), and the tear strength according to the right-angled tear method defined in JIS K7128-3 is not less than 25 (N / mm). Thermal transfer recording medium.   2. The thermal transfer recording medium according to claim 1, wherein a shrinkage ratio by heating at 150 ° C. for 30 minutes in the main scanning direction and the sub-scanning direction is less than 3%.

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