JP5664406B2 - Thermal transfer recording medium - Google Patents

Description

  The present invention relates to a thermal transfer recording medium. More specifically, it has high transfer sensitivity during high-speed printing, can reduce the amount of dye used in the dye layer, and can prevent abnormal transfer in printing even after storage under high temperature and high humidity. The present invention relates to a heat-sensitive transfer recording medium that can reduce the shine generated in the above.

  Generally, the thermal transfer recording medium is also called a thermal ribbon, and is an ink ribbon used in a thermal transfer printer. The thermal transfer recording medium has a substrate, a thermal transfer layer provided on one surface of the substrate, and a heat-resistant slipping layer (backcoat layer) provided on the other surface of the substrate. Here, the thermal transfer layer is an ink layer. When heat is generated in the thermal head of the printer, such heat is applied to the thermal transfer layer, and the ink constituting the thermal transfer layer is sublimated (sublimation transfer method) or melted. (Melting transfer method), and the ink is transferred to the transfer target side.

  Currently, among the thermal transfer systems, the sublimation transfer system is capable of forming various images easily and in full color along with the enhancement of printer functionality, so it can be used for cards such as digital camera self-prints and identification cards, and for amusement. Widely used in the field of output products. As described above, along with diversification of applications, there is a demand for downsizing, high speed, low cost, and durability for the obtained printed matter. In recent years, a thermal transfer recording medium having a plurality of thermal transfer layers provided on a substrate so as not to overlap with a protective layer or the like that imparts durability to a printed material is becoming widespread.

  Among them, with the diversification and widespread use of applications, the printing speed of printers has been further increased. Accordingly, the conventional thermal transfer recording medium has a problem that a sufficient print density cannot be obtained. Therefore, in order to increase the transfer sensitivity, attempts have been made to improve the transfer sensitivity in printing by reducing the thickness of the thermal transfer recording medium. However, wrinkles are caused by heat, pressure, etc. during the production of the thermal transfer recording medium or during printing. There is a problem that it occurs or the thermal transfer recording medium itself is broken in some cases.

  In addition, attempts have been made to improve the printing density and transfer sensitivity in printing by increasing the dye / resin (Dye / Binder) ratio in the dye layer of the thermal transfer recording medium, but the amount of dye used will increase. In addition to the cost increase, a part of the dye migrates to the heat-resistant slip layer of the thermal transfer recording medium when it is wound up in the manufacturing process (setback), and when the rewinding is performed, the migrated dye has a different color. When the dye layer or the protective layer is re-transferred (backside back) and the contaminated layer is thermally transferred to the transfer material, there is a problem that a so-called background stain occurs such as a hue different from the designated color.

  Attempts have also been made to increase the energy at the time of image formation on the printer side, but this not only increases power consumption, but also shortens the life of the thermal head of the printer, and fuses the dye layer and the transfer target. However, there is a problem that so-called abnormal transfer is likely to occur. In order to prevent such abnormal transfer, attempts have been made to add a large amount of a release agent to the dye layer or the transfer target, but there is a problem that bleeding or background smearing occurs in the obtained image. is there.

  In order to solve such a conventional problem, for example, Patent Document 1 discloses a thermal transfer sheet having an adhesive layer containing a polyvinylpyrrolidone resin and a modified polyvinylpyrrolidone resin between a base material and a dye layer. .

  Patent Document 2 discloses a thermal transfer sheet having an adhesive layer composed of a polyvinyl pyrrolidone resin or a polyvinyl alcohol resin thermoplastic resin and colloidal inorganic pigment ultrafine particles between a base material and a dye layer.

  Patent Document 3 discloses a thermal transfer sheet having a base layer composed of a copolymer of vinylpyrrolidone and vinyl acetate and colloidal inorganic pigment ultrafine particles between a base material and a dye layer.

JP-A-2005-231354 JP 2006-150956 A JP 2008-155612 A

  However, when the thermal transfer recording medium described in Patent Document 1 is printed using a sublimation transfer type high-speed printer, even if the thermal transfer recording medium stored at high temperature and high humidity is used, abnormal transfer is performed. However, there is a problem that the transfer sensitivity in printing is low and the shine cannot be sufficiently suppressed. In addition, when the thermal transfer recording medium described in Patent Document 2 is used for printing in the same manner, abnormal transfer is confirmed when the thermal transfer recording medium stored at high temperature and high humidity is used, There is a problem that it cannot be suppressed sufficiently. Further, when printing is performed by the same method using the thermal transfer recording medium described in Patent Document 3, there is a problem that uneven printing is confirmed and the shine cannot be sufficiently suppressed. Thus, when the conventional thermal transfer recording medium is used, the transfer sensitivity in printing is high, and even when the thermal transfer recording medium stored at high temperature and high humidity is used, abnormal transfer does not occur, There is no thermal transfer recording medium that can sufficiently cope with high-speed printers with sufficiently improved shine.

  In view of the above problems, the present invention has high transfer sensitivity during high-speed printing, can reduce the amount of dye used in the dye layer, and prevents abnormal transfer in printing even after storage under high temperature and high humidity. Further, it is an object of the present invention to provide a thermal transfer recording medium that can reduce the shine generated in the high density portion.

The thermal transfer recording medium of the present invention comprises a base material, a heat-resistant slip layer formed on one surface of the base material, an undercoat layer formed on the other surface of the base material, and the undercoat layer. The undercoat layer comprises a silicon compound represented by the following general formula (1) and / or a hydrolyzate thereof, and the following general formula (2): It includes a silicon compound and / or a hydrolyzate thereof, a water-soluble polymer, and a vinylpyrrolidone-vinylimidazole copolymer, wherein the water-soluble polymer is polyvinyl alcohol and / or polyvinylpyrrolidone. And By having such a configuration, the present invention has high transfer sensitivity during high-speed printing, can reduce the dye used in the dye layer, and prevents abnormal transfer in printing even after storage under high temperature and high humidity. In addition, it is possible to provide a thermal transfer recording medium that can reduce the shine generated in the high density portion.
Si (OR ¹ ) ₄ (1)
(Wherein R ¹ represents CH ₃ , C ₂ H ₅ or C ₂ H ₄ OCH ₃ )
(R ² Si (OR ³ ) ₃ ) _n (2)
(Wherein R ² represents an organic functional group, R ³ represents CH ₃ , C ₂ H ₅ or C ₂ H ₄ OCH ₃ , and n is an integer of 1 to 100)

In the general formula (2), when n is 1, R ² is an isocyanate group, and when n is 2 to 100, the silicon compound represented by the general formula (2) having the isocyanate group and / or Alternatively, it is preferable that the hydrolyzate is condensed with each other to form an isocyanurate, and a trimer 1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate represented by the following general formula (3) It is more preferable that By having such a configuration, it is effective that the undercoat layer having hydrogen bonds swells with water when stored for a long period of time under high temperature and high humidity, resulting in deterioration of performance, resulting in a decrease in adhesion. Can be suppressed.
_{(NCO- (CH 2) n Si} (OR 3) 3) 3 (3)
(Wherein R ³ represents CH ₃ , C ₂ H ₅ or C ₂ H ₄ OCH ₃ , and n is an integer of 1 to 100)

  The silicon compound represented by the general formula (1) is preferably tetraethoxysilane. By having such a configuration, the adhesion between the dye layer and the undercoat layer at high temperature and high humidity is improved, and abnormal transfer can be prevented.

The undercoat layer is preferably formed by being applied within a range of 0.10 to 0.30 g / m ² as a coating amount after drying. By having such a configuration, the transfer sensitivity is good even during high-speed printing, and the adhesion to the substrate or dye layer is also good.

  The thermal transfer recording medium of the present invention has high transfer sensitivity during high-speed printing, can reduce the dye used in the dye layer, and prevents abnormal transfer in printing even after storage under high temperature and high humidity. In addition, it is possible to provide a thermal transfer recording medium that can reduce the shine generated in the high density portion.

1 is a side sectional view of a thermal transfer recording medium according to an embodiment of the present invention.

  A thermal transfer recording medium according to an embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a side sectional view of a thermal transfer recording medium according to an embodiment of the present invention. As shown in FIG. 1, the thermal transfer recording medium in the present embodiment includes a base material 1, a heat-resistant slip layer 2 formed on one surface of the base material 1, and the other of the base material 1. It consists of an undercoat layer 3 formed on the surface and a dye layer 4 formed on the undercoat layer 3. The heat resistant slipping layer 2 is provided for the purpose of imparting slipperiness with the thermal head.

  The material of the substrate 1 is required to have heat resistance and strength so as not to be softened and deformed by heat pressure in thermal transfer. For example, polyethylene terephthalate, polyethylene naphthalate, polypropylene, cellophane, acetate, polycarbonate, polysulfone, polyimide , Synthetic resin films such as polyvinyl alcohol, aromatic polyamide, aramid, polystyrene, and papers such as condenser paper and paraffin paper can be used alone or in combination. Among these, it is preferable to use a polyethylene terephthalate film in consideration of physical properties, workability, cost, and the like. Further, the thickness of the substrate 1 is preferably 2 to 50 μm in consideration of operability and workability, and 2 to 9 μm from the viewpoint of good handling properties such as transfer suitability and workability. It is preferable to use a material having a certain thickness.

  Moreover, it is possible to perform an adhesion treatment on the surface of the base material 1 on which the heat resistant slipping layer 2 and / or the undercoat layer 3 is formed. As the adhesion treatment, known treatments such as corona treatment, flame treatment, ozone treatment, ultraviolet treatment, radiation treatment, surface roughening treatment, plasma treatment, and primer treatment can be applied, and two or more of these treatments are used in combination. You can also In the present embodiment, it is preferable to use a primer-treated polyethylene terephthalate film from the viewpoint that the adhesiveness between the substrate 1 and the undercoat layer 3 can be improved satisfactorily and is excellent in terms of cost.

Next, conventionally known materials can be used as the material of the heat resistant slipping layer 2. For example, a resin serving as a binder, a functional additive imparting releasability and slipperiness, a filler, a curing agent, a solvent, and the like can be used, and these can be formed by coating and drying. Coating amount after drying of the heat-resistant slipping layer 2 is about 0.1 to 2.0 g / m ² are suitable.

  Examples of the binder resin include polyvinyl butyral resin, polyvinyl acetoacetal resin, polyester resin, vinyl chloride-vinyl acetate copolymer, polyether resin, polybutadiene resin, acrylic polyol, polyurethane acrylate, polyester acrylate, polyether acrylate, and epoxy. Examples include acrylate, nitrocellulose resin, cellulose acetate resin, polyamide resin, polyimide resin, polyamideimide resin, and polycarbonate resin. Functional additives include animal waxes, natural waxes such as plant waxes, synthetic hydrocarbon waxes, aliphatic alcohols and acid waxes, fatty acid esters and glycerite waxes, synthetic ketone waxes, amine and amide waxes Synthetic waxes such as chlorinated hydrocarbon waxes and alpha-olefin waxes, higher fatty acid esters such as butyl stearate and ethyl oleate, sodium stearate, zinc stearate, calcium stearate, potassium stearate, magnesium stearate, etc. Surfactants such as higher fatty acid metal salts, long-chain alkyl phosphate esters, polyoxyalkylene alkyl aryl ether phosphate esters, or phosphate esters such as polyoxyalkylene alkyl ether phosphate esters, etc. It can be mentioned. As fillers, talc, silica, magnesium oxide, zinc oxide, calcium carbonate, magnesium carbonate, kaolin, clay, silicone particles, polyethylene resin particles, polypropylene resin particles, polystyrene resin particles, polymethyl methacrylate resin particles, polyurethane resin particles, etc. Can be mentioned. As the curing agent, isocyanates such as tolylene diisocyanate, triphenylmethane triisocyanate, tetramethylxylene diisocyanate, and derivatives thereof can be used.

  The undercoat layer 3 includes, as essential components, a silicon compound represented by the general formula (1) and a hydrolyzate thereof, a silicon compound represented by the general formula (2) and a hydrolyzate thereof, and vinylpyrrolidone- A coating solution containing a vinylimidazole copolymer and a water-soluble polymer as main components can be applied and dried.

As the silicon compound represented by the general formula (1) and the hydrolyzate thereof, those in which R ¹ can be represented by CH ₃ , C ₂ H ₅ , C ₂ H ₄ OCH ₃ or the like are preferable. Silane (R ¹ is C ₂ H ₅ ) is more preferable from the viewpoint of being stable in an aqueous solvent after hydrolysis.
Si (OR ¹ ) ₄ (1)
(Wherein R ¹ represents CH ₃ , C ₂ H ₅ or C ₂ H ₄ OCH ₃ )
(R ² Si (OR ³ ) ₃ ) _n (2)
(Wherein R ² represents an organic functional group, R ³ represents CH ₃ , C ₂ H ₅ or C ₂ H ₄ OCH ₃ , and n is an integer of 1 to 100)

  The silicon compound represented by the general formula (1) and the hydrolyzate thereof are condensed after hydrolysis to form a chain or three-dimensional polymer. Here, since silicon oxide is generally hard and tends to crack due to distortion due to volume reduction during condensation, it is very difficult to form a thin, transparent and uniform condensate film on the film. Therefore, in the present embodiment, a water-soluble polymer, which will be described later, is added to the undercoat layer 3 to impart flexibility and to form a film while preventing cracks. The silicon compound and the hydrolyzate thereof form a complex at the molecular level with a water-soluble polymer, which will be described later, and can improve the transfer sensitivity during high-speed printing, which tends to be insufficient only with the water-soluble polymer.

  However, in the undercoat layer 3, when the silicon compound represented by the general formula (1) and the hydrolyzate thereof and a water-soluble polymer are mixed, the undercoat layer 3 during long-term storage at high temperature and high humidity. Swells with water, and deterioration in performance tends to cause a decrease in adhesion.

  On the other hand, in this Embodiment, this swelling can be prevented by adding the silicon compound represented by the said General formula (2) and its hydrolyzate.

In the general formula (2), the organic functional group (R ₂ ) is preferably a non-aqueous functional group such as vinyl, epoxy, methacryloxy, ureido, and isocyanate. Thus, water resistance can be further improved by having a non-aqueous functional group. In general formula (2), when n is a multimer of 2 or more, a trimer is preferable, and 1,3,5-tris (3-trialkoxysilylalkyl) represented by the following general formula (3) Isocyanurate is more preferred. In addition, 1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate represented by the following general formula (3) is a condensate of 3-isocyanatoalkylalkoxysilane, and is substantially in the isocyanurate part. However, since the isocyanurate part has polarity, it is known that it exhibits the same performance as a chemical reaction. In addition, 1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate is generally added to an adhesive or the like in the same manner as 3-isocyanatoalkylalkoxysilane, and is known as an adhesion improver. Yes. Therefore, by adding to the silicon compound represented by the general formula (1) and the hydrolyzate thereof and the water-soluble polymer, it is possible to prevent swelling due to water and improve the moisture resistance of the resulting ink. . Some 1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate is produced by thermal condensation of 3-isocyanatopropylalkoxysilane, and 3-isocyanatepropylalkoxysilane as a raw material is in the system. In this case, there is no particular problem in physical properties.
_{(NCO- (CH 2) n Si} (OR 3) 3) 3 (3)
(Wherein R ³ represents CH ₃ , C ₂ H ₅ or C ₂ H ₄ OCH ₃ , and n is an integer of 1 to 100)

  The vinylpyrrolidone-vinylimidazole copolymer is a copolymer of an N-vinylpyrrolidone-based monomer and vinylimidazole that is a vinyl polymerizable monomer. As a form of copolymerization, a form obtained by a conventionally known polymerization method such as random copolymerization, block copolymerization, or graft copolymerization can be employed.

  In the present embodiment, the N-vinylpyrrolidone-based monomer refers to N-vinylpyrrolidone (including N-vinyl-2-pyrrolidone, N-vinyl-4-pyrrolidone, and the like) and derivatives thereof. For example, the pyrrolidone ring such as N-vinyl-3-methylpyrrolidone, N-vinyl-5-methylpyrrolidone, N-vinyl-3-benzylpyrrolidone, N-vinyl-3,3,5-trimethylpyrrolidone has a substituent. Although it can mention a thing, it is not specifically limited.

  As the water-soluble polymer, for example, polyvinyl alcohol, polyvinyl pyrrolidone, starch, gelatin, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, sodium alginate and the like can be used. Among these, it is preferable to use polyvinyl alcohol and polyvinyl pyrrolidone, and it is more preferable to use polyvinyl alcohol. The polyvinyl alcohol used in the present embodiment is generally obtained by saponifying polyvinyl acetate. Among them, so-called partially saponified polyvinyl alcohol in which several tens percent of acetate groups remain, acetic acid Also included are so-called fully saponified polyvinyl alcohols in which only a few% of the groups remain.

The coating amount after drying of the undercoat layer 3, but are not unconditionally limited, it is preferably in the range of 0.10~0.30g / m ^2. If it is less than 0.10 g / m ² , the transfer sensitivity at the time of high-speed printing tends to be insufficient or the adhesion to the substrate or the dye layer tends to be a problem due to deterioration when the dye layer is laminated. On the other hand, if it exceeds 0.30 g / m ² , the sensitivity of the thermal transfer recording medium itself tends to be low, and the transfer sensitivity at the time of high-speed printing tends to be insufficient.

The method for forming the dye layer 4 is not particularly limited. For example, the dye layer 4 is formed by preparing a dye layer forming coating solution by blending a heat transferable dye, a binder, a solvent, and the like, and applying and drying the coating solution. The coating amount of the dye layer forming coating solution for forming the dye layer 4 is appropriately about 1.0 g / m ² . The dye layer 4 can be formed as a single layer of one color, and a plurality of dye layers containing dyes having different hues can be sequentially and repeatedly formed on the same surface of the same substrate 1.

  The heat transferable dye is not particularly limited as long as it is a dye that melts, diffuses, or sublimates and transfers due to heat. For example, the yellow component includes solvent yellow 56, 16, 30, 93, 33, Disperse Yellow 201, 231, 33, etc. can be used. Examples of the magenta component include C.I. I. Disperse thread 60, C.I. I. Disperse violet 26, C.I. I. Solvent Red 27, or C.I. I. Solvent red 19 or the like can be used. As the cyan component, C.I. I. Disperse Blue 354, C.I. I. Solvent Blue 63, C.I. I. Solvent Blue 36, or C.I. I. Disperse Blue 24 or the like can be used. As the ink dye, those prepared by combining the above dyes can generally be used.

  As the binder, any conventionally known resin binder can be used, and is not particularly limited. Cellulose resins such as ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, and cellulose acetate, polyvinyl alcohol, Vinyl resins such as polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl pyrrolidone, and polyacrylamide, polyester resins, styrene-acrylonitrile copolymer resins, phenoxy resins, and the like can be used.

  The ratio between the heat transferable dye and the binder is preferably heat transferable dye / binder = 10/100 to 300/100. This is because when the ratio of the heat transferable dye is less than 10, there is too little heat transferable dye and the color development sensitivity becomes insufficient, and a good heat transfer image tends not to be obtained. On the other hand, when it exceeds 300, the solubility of the dye in the binder is extremely lowered, so that when it becomes a thermal transfer recording medium, the storage stability tends to deteriorate and the dye tends to precipitate. Moreover, well-known additives, such as an isocyanate compound, a silane coupling agent, a dispersing agent, a viscosity modifier, and a stabilizer, can be used for the dye layer or the dye layer forming coating solution as long as the performance is not impaired.

  The image receiving paper base material to be transferred to be used in the present embodiment will be described.

  As the image receiving paper base, papers mainly composed of cellulose pulp can be used. Examples of papers that can be used include coated paper, art paper, high-quality paper (acidic paper, neutral paper), medium-quality paper, and glassine paper.

  Furthermore, it is preferable to form a heat insulating layer containing hollow particles and an adhesive component on the image receiving paper substrate. Since thermal transfer printing is performed by heating from a thermal head, the better the adhesion between the thermal head and the image receiving paper substrate, the better. As described above, when the heat insulating layer is formed on the image receiving paper base material, the formed heat insulating layer has cushioning properties, so that the adhesion with the thermal head is improved and the printing is more uniform during printing. An image can be obtained.

  As a material for forming the hollow particles, acrylonitrile, vinylidene chloride, a polymer of styrene acrylate, or the like is preferably used. As a method for producing the hollow particles, a method of encapsulating a foaming agent such as butane gas in the resin particles and heating and foaming, an emulsion polymerization method, or the like can be employed. As a method of heating and foaming, when using pre-foamed hollow particles obtained by foaming hollow particles in advance by heat treatment, and after forming a heat insulating layer containing unfoamed particles by coating or the like, by heat treatment such as a drying step In some cases, a hollow structure is formed in the heat insulating layer. Among them, it is preferable to use the already-expanded particles because it is easy to control the hollow ratio and particle diameter of the hollow particles to be constant.

  As the dyeing resin used for the image receiving layer formed on the image receiving paper substrate or the heat insulating layer, a thermoplastic resin having high affinity for the heat transferable dye and good dye dyeing property is used. be able to. Specifically, for example, vinyl chloride resin, urethane resin, polyester resin, polycarbonate resin, polyvinyl acetal resin, polyvinyl butyral resin, polystyrene resin, polyacrylate resin, acrylic resin, cellulose resin, polyamide resin Further, a thermoplastic resin such as a copolymer resin of a vinyl compound monomer and a monomer having a benzotriazole skeleton and / or a benzophenone skeleton can be used. These thermoplastic resins may be used alone or in combination of two or more. The dyeable resin is preferably a water-soluble or water-dispersed so-called aqueous resin from the viewpoint of environmental burden.

  In thermal transfer printing, there is a step of peeling the ink ribbon from the image receiving layer after heating with a thermal head in a state where the image receiving layer on the image receiving paper substrate and the dye layer of the ink ribbon are superimposed. At that time, since the image receiving layer is required to be releasable from the ink ribbon, it is preferable to add a releasing agent for the purpose of preventing fusion with the ink ribbon and improving printing runnability. Examples of the release agent to be added include silicone oil, polysiloxane graft acrylic resin, waxes, and fluorine compounds.

  It is preferable to improve the heat resistance by adding a crosslinking agent to the image receiving layer. As a crosslinking agent, a carbodiimide compound, an isocyanate compound, an oxazoline compound, and an organic titanium chelate compound can be used. Among these, a carbodiimide-based crosslinking agent is preferable because it has a high effect of improving heat resistance, is less likely to cause running problems such as ribbon fusion during printing, and is stable in water-based paints. The addition amount of the carbodiimide-based crosslinking agent is preferably 1 to 30 parts by mass and more preferably 3 to 25 parts by mass with respect to 100 parts by mass of the resin contained in the image receiving layer. If the amount is less than 1 part by mass, sufficient crosslinking effect cannot be obtained, and printing running failure tends to occur. On the other hand, when it exceeds 30 parts by mass, there is a tendency for the density of the printed image to decrease because the curing agent inhibits the dyeability of the resin.

The coating amount of the image-receiving layer is preferably ^{0.5~5g / m 2, 0.5~4g / m} 2 is more preferable. When it is less than 0.5 g / m ² , the light resistance of the image tends to be inferior. On the other hand, if it exceeds 5 g / m ² , the dye diffuses in the image receiving layer and the image tends to blur.

  The heat-sensitive transfer recording medium of the present invention will be specifically described below with reference to examples. The present invention is not limited to the following examples.

The raw materials used are shown below. In the text, “part” means part by mass unless otherwise specified.
<Preparation of substrate with heat-resistant slip layer>
As a base material, a polyethylene terephthalate film with a single-sided easy adhesion treatment of 4.5 μm is used, and a heat resistant slipping layer coating solution having the following composition is applied to the non-easy adhesion treatment surface by a gravure coating method so that the coating amount after drying is 1 After coating and drying so as to be 0.0 g / m ² , the substrate with a heat-resistant slipping layer was obtained by aging in a 40 ° C. environment for 1 week.
<Heat resistant slipping layer coating solution>
Acrylic polyol resin 12.5 parts Polyoxyalkylene alkyl ether / phosphate ester 2.5 parts Talc 6.0 parts 2,6-tolylene diisocyanate prepolymer 4.0 parts Toluene 50.0 parts Methyl ethyl ketone 20.0 parts Ethyl acetate 5.0 parts

<Preparation of undercoat layer coating solution>
A: To a mixed solution of 17.3 parts of tetraethoxysilane (Si (OC ₂ H ₅ ) ₄ ) and 10.0 parts of methanol, 72.7 parts of hydrochloric acid (0.1N) is added and stirred for 30 minutes. The undercoat layer coating solution A was hydrolyzed.
B: Dissolve 2.0 parts of polyvinyl alcohol and 3.0 parts of vinylpyrrolidone-vinylimidazole copolymer (copolymerization ratio: 1/1) in a mixed solution of 90.0 parts of water and 5.0 parts of methanol. Thus, the undercoat layer coating solution B was obtained.
C: Dissolve 2.0 parts of polyvinylpyrrolidone and 3.0 parts of vinylpyrrolidone-vinylimidazole copolymer (copolymerization ratio: 1/1) in a mixed solution of 90.0 parts of water and 5.0 parts of methanol. Thus, an undercoat layer coating solution C was obtained.
D: In a mixed solution of 90.0 parts of water and 5.0 parts of methanol, 1.5 parts of polyvinyl alcohol, 1.5 parts of polyvinylpyrrolidone and 2.0 parts of vinylpyrrolidone-vinylimidazole copolymer were dissolved. An undercoat layer coating solution D was obtained.
E: 5.0 parts of vinylpyrrolidone-vinylimidazole copolymer (copolymerization ratio: 1/1) was dissolved in a mixed solution of 90.0 parts of water and 5.0 parts of methanol to obtain an undercoat layer coating solution E. It was.
F: 5.0 parts of polyvinyl alcohol was dissolved in a mixed solution of 90.0 parts of water and 5.0 parts of methanol to obtain an undercoat layer coating solution F.
G: 5.0 parts of vinylpyrrolidone was dissolved in a mixed solution of 90.0 parts of water and 5.0 parts of methanol to obtain an undercoat layer coating solution G.
H: 2.5 parts of polyvinyl alcohol and 2.5 parts of vinylpyrrolidone were dissolved in a mixed solution of 90.0 parts of water and 5.0 parts of methanol to prepare an undercoat layer coating solution H.
I: 45.0 parts of water, 45.0 parts of IPA, and 10.0 parts of 1,3,5-tris (3-methoxysilylpropyl) isocyanurate were mixed and stirred for 5 minutes. did.

<Preparation of image receiving paper to be transferred>
<Preparation of image receiving paper substrate>
Art paper having a thickness of 180 g / m ² was used as the image receiving paper substrate.

<Formation of heat insulation layer>
On the image receiving paper substrate, the following composition heat insulating layer coating solution was applied and dried by gravure coating so that the coating amount after drying was 10 g / m ² , and aged in a 40 ° C. environment for 1 week. Then, an image receiving paper with a heat insulating layer was prepared.
<Insulation layer coating solution>
45 parts of pre-expanded hollow particles made of a copolymer mainly composed of acrylonitrile and methacrylonitrile (average particle diameter: 3.2 μm, volume hollow ratio: 85%)
Polyvinyl alcohol 10 parts Vinyl chloride vinyl acetate copolymer resin dispersion 45 parts (vinyl chloride / vinyl acetate = 70/30, glass transition temperature (T _g ): 64 ° C.)
200 parts of water

<Formation of image receiving layer>
On the heat insulation layer, the following composition image-receiving layer coating solution is applied and dried by a gravure coating method so that the coating amount after drying is 4 g / m ^2, and is aged in a 40 ° C. environment for 1 week to receive the image. A layer was made.
<Image-receiving layer coating solution>
97 parts of urethane resin ( _Tg : -20 ° C)
Associative urethane thickener 1 part Sulfonic acid surfactant 2 parts Water 200 parts

Example 1
The undercoat layer coating solution A, the undercoat layer coating solution B, and the undercoat layer coating solution I prepared above are applied to the easy-adhesion treated surface of the substrate with a heat resistant slipping layer by A / B / I = 70/20 / The undercoat layer was formed by applying and drying the coating solution mixed to 10 and stirred for 30 minutes by a gravure coating method so that the coating amount after drying was 0.2 g / m ² . On the undercoat layer, a dye layer coating solution having the following composition is applied by a gravure coating method so that the coating amount after drying is 0.7 g / m ² and dried to form a dye layer. A thermal transfer recording medium was produced.
<Dye layer coating solution>
C. I. Solvent Blue 63 6.0 parts Polyvinyl acetal resin 4.0 parts Toluene 45.0 parts Methyl ethyl ketone 45.0 parts

(Example 2)
The undercoat layer coating solution to be used was an undercoat layer coating solution A, an undercoat layer coating solution C, and an undercoat layer coating solution I, except that they were mixed at A / C / I = 70/20/10, respectively. In the same manner as in Example 1, a thermal recording transfer medium was produced.

Example 3
The undercoat layer coating solution to be used is an undercoat layer coating solution A, an undercoat layer coating solution D, and an undercoat layer coating solution I, except that they were mixed at A / D / I = 70/20/10, respectively. In the same manner as in Example 1, a thermal recording transfer medium was produced.

Example 4
A thermal recording transfer medium was produced in the same manner as in Example 3 except that the undercoat layer was coated and dried so that the coating amount after drying was 0.05 g / m ² .

(Example 5)
A thermal recording transfer medium was produced in the same manner as in Example 3 except that the undercoat layer was coated and dried so that the coating amount after drying was 0.35 g / m ² .

(Comparative Example 1)
After forming the undercoat layer on the easy-adhesion treated surface of the substrate with a heat-resistant slipping layer, the same dye layer coating solution as in Example 1 is dried on the easy-adhesive treated surface by a gravure coating method. the coating amount of the coating is such that 0.7 g / m ^2, and dried to form a dye layer to prepare a thermal transfer recording medium.

(Comparative Example 2)
The undercoat layer coating solution to be used is an undercoat layer coating solution A, an undercoat layer coating solution E, and an undercoat layer coating solution I, except that they were mixed at A / E / I = 70/20/10, respectively. In the same manner as in Example 1, a thermal recording transfer medium was obtained.

(Comparative Example 3)
The undercoat layer coating solution to be used is an undercoat layer coating solution A, an undercoat layer coating solution F, and an undercoat layer coating solution I, except that they were mixed at A / F / I = 70/20/10, respectively. In the same manner as in Example 1, a thermal recording transfer medium was obtained.

(Comparative Example 4)
The subbing layer coating liquid to be used is the subbing layer coating liquid A, the subbing layer coating liquid G, and the subbing layer coating liquid I, except that they were mixed at A / G / I = 70/20/10, respectively. In the same manner as in Example 1, a thermal recording transfer medium was obtained.

(Comparative Example 5)
The undercoat layer coating solution to be used was an undercoat layer coating solution A, an undercoat layer coating solution H, and an undercoat layer coating solution I, except that they were mixed at A / H / I = 70/20/10, respectively. In the same manner as in Example 1, a thermal recording transfer medium was obtained.

(Comparative Example 6)
The thermal recording transfer medium was the same as in Example 1 except that the undercoat layer coating solution used was an undercoat layer coating solution A and an undercoat layer coating solution D, and each was mixed at A / D = 70/30. Got.

(Comparative Example 7)
A thermal recording transfer medium was obtained in the same manner as in Example 1 except that the undercoat layer coating solution used was only the undercoat layer coating solution D.

<Print evaluation>
Regarding the thermal transfer recording media of Examples 1 to 5 and Comparative Examples 1 to 7, the thermal transfer recording media stored at room temperature, and after being stored in an environment of 50 ° C. and 80% RH for 72 hours, further 24 at room temperature. Using the thermal transfer recording medium and the transfer medium stored for a long time, solid printing is performed with a thermal simulator (manufactured by Wedge Corp.), and the presence or absence of abnormal transfer and the evaluation of shine are evaluated according to the following criteria. In addition, the maximum reflection density is measured. The results are shown in Table 1. Note that the maximum reflection density is a value obtained by measuring a printed portion where no shine is confirmed with a concentration meter (X-Rite 528, manufactured by X-Rite).

<Printing conditions>
Printing environment: 23 ° C, 50% RH
Applied voltage: 29V
Line cycle: 0.7msec
Print density: main scanning 300 dpi sub-scanning 300 dpi
<Evaluation criteria for abnormal transcription>
○: Abnormal transfer to the transfer object is not observed. Δ: Abnormal transfer to the transfer object is very slight. ×: Abnormal transfer to the transfer object is observed on the entire surface. >
○: shine is not recognized △: shine is partially recognized ×: shine is clearly recognized

  As shown in Table 1, in the thermal transfer recording media according to Comparative Examples 3 to 5 prepared without using the vinylpyrrolidone-vinyl imidazole copolymer, shine was clearly recognized. In the heat-sensitive transfer recording medium produced in (1), no shine was observed, and the effect of using a vinylpyrrolidone-vinylimidazole copolymer was confirmed. In addition, the thermal transfer recording medium manufactured in Examples 1 to 5 has a reflection density of 2.3 or higher and the transfer sensitivity is higher than that of the thermal transfer recording medium manufactured in Comparative Example 1 in which no undercoat layer is provided. It turned out to be high enough.

  The thermal transfer recording medium of the present invention has high transfer sensitivity during high-speed printing, can reduce the dye used in the dye layer, and can prevent abnormal transfer in printing even after storage at high temperature and high humidity. Further, since the shine generated in the high density portion can be reduced, it can be suitably used in the fields of self-printing digital cameras, cards such as identification cards, amusement output products, and the like.

DESCRIPTION OF SYMBOLS 1 Base material 2 Heat resistant slipping layer 3 Undercoat layer 4 Dye layer

Claims (5)

A substrate;
A heat resistant slipping layer formed on one surface of the substrate;
An undercoat layer formed on the other surface of the substrate;
A thermal transfer recording medium comprising a dye layer formed on the undercoat layer,
The undercoat layer is
A silicon compound represented by the following general formula (1) and / or a hydrolyzate thereof,
A silicon compound represented by the following general formula (2) and / or a hydrolyzate thereof,
A water-soluble polymer,
Vinylpyrrolidone-vinylimidazole copolymer,
The heat-sensitive transfer recording medium, wherein the water-soluble polymer is polyvinyl alcohol and / or polyvinyl pyrrolidone.
Si (OR ¹ ) ₄ (1)
(Wherein R ¹ represents CH ₃ , C ₂ H ₅ or C ₂ H ₄ OCH ₃ )
(R ² Si (OR ³ ) ₃ ) _n (2)
(Wherein R ² represents an organic functional group, R ³ represents CH ₃ , C ₂ H ₅ or C ₂ H ₄ OCH ₃ , and n is an integer of 1 to 100) In the general formula (2),
when n is 1, R ² is an isocyanate group;
When n is 2 to 100, the silicon compound represented by the general formula (2) having an isocyanate group and / or a hydrolyzate thereof are condensed with each other to form an isocyanurate. 1. The thermal transfer recording medium according to 1. The general formula (2) is a trimer 1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate represented by the following general formula (3). Thermal transfer recording medium.
_{(NCO- (CH 2) n Si} (OR 3) 3) 3 (3)
(Wherein R ³ represents CH ₃ , C ₂ H ₅ or C ₂ H ₄ OCH ₃ , and n is an integer of 1 to 100)   The thermal transfer recording medium according to claim 1, wherein the silicon compound represented by the general formula (1) is tetraethoxysilane. The undercoat layer is formed by being applied within a range of 0.10 to 0.30 g / m ² as a coating amount after drying. Thermal transfer recording medium.

Images