JP4074294B2 - Thermal transfer sheet - Google Patents

Description

  The present invention relates to a thermal transfer sheet in which a heat-resistant slipping layer is provided on one surface of a substrate, and an adhesive layer and a dye layer are sequentially formed on the other surface of the substrate. The present invention relates to a thermal transfer sheet that can prevent abnormal transfer such that the entire dye layer is transferred during printing on a transfer body.

  Conventionally, various thermal transfer recording methods are known. Among them, a thermal transfer sheet having a dye layer in which a dye for sublimation transfer is used as a recording material and this is supported on a base material such as a polyester film with a suitable binder. From the above, there are proposed methods for forming various full-color images by thermally transferring a sublimation dye onto a transfer material that can be dyed with a sublimation dye, for example, a thermal transfer image-receiving sheet having a dye-receiving layer formed on paper or a plastic film. Yes. In this case, as the heating means, the color dots having a large number of three or four colors adjusted by heating with the thermal head of the printer are transferred to the receiving layer of the thermal transfer image receiving sheet, and the multicolored color dots are transferred. To reproduce the full color of the document. The image formed in this way is very clear and excellent in transparency because the coloring material used is a dye, so the resulting image is excellent in the reproducibility and gradation of intermediate colors, It is possible to form a high-quality image similar to an image obtained by offset printing or gravure printing and comparable to a full-color photographic image.

  In such a thermal transfer recording system using sublimation transfer, as the printing speed of the thermal transfer printer is increased, there has been a problem that a sufficient print density cannot be obtained with the conventional thermal transfer sheet. Also, there has been a demand for higher density and clearer prints of thermal transfer images, and improved thermal transfer image-receiving sheets that accept images of sublimation dyes transferred from the thermal transfer sheet and the thermal transfer sheet. Many attempts have been made. For example, attempts have been made to improve transfer sensitivity in printing by reducing the thickness of the thermal transfer sheet, but wrinkles may occur due to heat, pressure, etc. during manufacture of the thermal transfer sheet or during thermal transfer recording. Causes the problem of cutting.

  In addition, the dye / resin (Dye / Binder) ratio in the dye layer of the thermal transfer sheet was increased to try to improve the printing density and the transfer sensitivity in the printing. When the dye is transferred to the heat-resistant slipping layer of the material and the transferred dye is rolled back, it is re-transferred to the dye layer of another color (kickback), and the contaminated layer is thermally transferred to the image receiving sheet. The hue may be different from that of the original color, or the so-called background stain may occur. In the thermal transfer printer, not on the thermal transfer sheet side, high energy was applied during thermal transfer during image formation. However, the dye layer and the receiving layer are fused, and so-called abnormal transfer is likely to occur. When a large amount of a release agent is added to the receiving layer to prevent the abnormal transfer, blurring of the image, background smearing, etc. occur.

  In addition, as a prior art, Patent Document 1 discloses a thermal transfer in which a hydrophilic barrier / undercoat layer using polyvinyl pyrrolidone as a main component and polyvinyl alcohol as a component for improving dye transfer efficiency is provided between a dye layer and a support. A sheet is disclosed. This polyvinyl pyrrolidone is for preventing abnormal transfer and preventing adhesion at the time of printing.Polyvinyl alcohol has a function of improving transfer sensitivity, and that polyvinyl pyrrolidone improves transfer sensitivity. There is no description.

  In addition, the present applicant describes in Patent Document 2 that the use of a dye layer primer layer containing polyvinyl pyrrolidone has the effect of increasing the sensitivity in thermal transfer and abnormal transfer. Depending on the properties, the adhesion of the primer layer decreases, especially under high temperature and high humidity, and the dye layer is taken together with the receiving layer of the image receiving sheet during thermal transfer, or because the primer layer and the dye layer are mixed. There arises a problem that the receiving layer is taken together with the possible dye layer.

As described above, thermal transfer recording materials for thermal transfer sheets and thermal transfer image-receiving sheets that can be adjusted and used on the thermal transfer printer side in response to higher printing speeds of thermal transfer and higher density and quality requirements of thermal transfer images However, in this situation, a sufficient print density cannot be obtained, abnormal transfer occurs during thermal transfer, other problems occur, and a sufficiently high quality print cannot be obtained.
Japanese Examined Patent Publication No. 7-102746 Japanese Patent Application No. 14-181812

  Therefore, in order to solve the above-described problems, the present invention responds to the demand for higher printing speed of thermal transfer, higher density and higher quality of thermal transfer images, improved transfer sensitivity in printing, higher temperature and higher temperature. It is an object of the present invention to provide a thermal transfer sheet that prevents the occurrence of abnormal transfer, wrinkles and the like even under an environment such as in a humidity.

The invention according to claim 1 is a thermal transfer sheet in which a heat-resistant slipping layer is provided on one surface of a substrate, and an adhesive layer and a dye layer are sequentially formed on the other surface of the substrate. As a resin and a modifier of the resin, any one of cellulose acetate propionate or shellac resin is contained, and the modifier is in a ratio of 0.5% to 10% with respect to the total solid content of the adhesive layer. It contained, and adhesive layer, the coating amount after drying is characterized by a 0.05 to 0.3 g / m ^2.

The present invention provides a thermal transfer sheet in which a heat-resistant slipping layer is provided on one surface of a substrate, and an adhesive layer and a dye layer are sequentially formed on the other surface of the substrate. As a modifier, any one of cellulose acetate propionate or shellac resin is contained, and the modifier contains 0.5% to 10% of the total solid content of the adhesive layer , and is bonded. Since the layer has a coating amount when dried of 0.05 to 0.3 g / m ² , that is, it contains a modifier that can suppress the hygroscopicity of polyvinylpyrrolidone resin such as carboxylmethylcellulose resin. The pyrrolidone resin does not absorb moisture and the adhesiveness with the base material does not decrease. Therefore, the adhesiveness between the dye layer and the substrate can be improved even under an environment such as high temperature and high humidity, and abnormal transfer or the like can be prevented. In addition, transfer sensitivity is greatly improved during thermal transfer, and a high-density thermal transfer image can be obtained without applying high energy.

  FIG. 1 shows one embodiment of the thermal transfer sheet of the present invention, and a heat-resistant slipping layer 4 is provided on one surface of a substrate 1 to improve the slipperiness of the thermal head and prevent sticking. A linear polymer polyvinylpyrrolidone resin, an adhesive layer 2 containing a modifier of the resin, and a dye layer 3 are sequentially formed on the other surface of the substrate 1. However, the modifier contained in the adhesive layer is contained in a proportion of 0.5% to 10% with respect to the total solid content of the adhesive layer.

Hereinafter, each layer constituting the thermal transfer sheet of the present invention will be described in detail.
(Base material)
The base material 1 of the thermal transfer sheet used in the present invention may be any material as long as it has a conventionally known degree of heat resistance and strength. For example, it has a thickness of about 0.5 to 50 μm, preferably about 1 to 10 μm. Polyethylene terephthalate film, 1,4-polycyclohexylenedimethylene terephthalate film, polyethylene naphthalate film, polyphenylene sulfide film, polystyrene film, polypropylene film, polysulfone film, aramid film, polycarbonate film, polyvinyl alcohol film, cellophane, acetic acid Examples thereof include cellulose derivatives such as cellulose, polyethylene film, polyvinyl chloride film, nylon film, polyimide film, ionomer film, and the like.

  In the above-mentioned base material, it is common to perform an adhesion treatment on the surface on which the adhesive layer and the dye layer are formed. When the plastic film of the base material is formed by applying an adhesive layer thereon, the wettability, adhesiveness, etc. of the coating solution are likely to be insufficient, and therefore, an adhesive treatment is performed. As the adhesion treatment, known resin surface modification such as corona discharge treatment, flame treatment, ozone treatment, ultraviolet treatment, radiation treatment, surface roughening treatment, chemical treatment, plasma treatment, low temperature plasma treatment, primer treatment, grafting treatment, etc. Quality technology can be applied as it is. Two or more of these treatments can be used in combination. The primer treatment can be performed, for example, by applying a primer solution to an unstretched film at the time of film formation by melt extrusion of a plastic film and then stretching the film.

  Furthermore, it is also possible to apply and form a primer layer between the base material and the adhesive layer as the above-mentioned base material adhesion treatment. The primer layer can be formed from a resin as shown below. Polyester resin, Polyacrylate resin, Polyvinyl acetate resin, Polyurethane resin, Styrene acrylate resin, Polyacrylamide resin, Polyamide resin, Polyether resin, Polystyrene resin, Polyethylene resin, Polypropylene Examples thereof include resins, vinyl resins such as polyvinyl chloride resins and polyvinyl alcohol resins, and polyvinyl acetal resins such as polyvinyl acetoacetal and polyvinyl butyral. However, in the thermal transfer sheet in which the adhesive layer and the dye layer are sequentially formed on the base material of the present invention, the adhesive property of the adhesive layer to the base material is sufficiently high. It is possible to directly provide an adhesive layer.

(Adhesive layer)
The adhesive layer 2 provided between the base material and the dye layer in the thermal transfer sheet of the present invention contains a polyvinyl pyrrolidone resin and a modifier for the polyvinyl pyrrolidone resin. Examples of the polyvinylpyrrolidone resin include homopolymers of vinylpyrrolidone such as N-vinyl-2-pyrrolidone and N-vinyl-4-pyrrolidone, and copolymers thereof. In particular, a linear polymer polyvinyl pyrrolidone resin is preferably used because it is highly effective in improving the transfer sensitivity in printing and has adhesion between the dye layer and the substrate. As the polyvinyl pyrrolidone resin, those having a K value in the Fickencher formula of 60 or more are preferably used, and in particular, grades of K-60 to K-120 can be used, and the number average molecular weight is 30,000 to 280, About 000. When the polyvinyl pyrrolidone resin having a K value of less than 60 is used, the effect of improving transfer sensitivity in printing is reduced.

  Further, as the polyvinylpyrrolidone resin, not only the above-mentioned N-vinyl-2-pyrrolidone and N-vinyl-4-pyrrolidone monomers, but also N-vinyl-3-methylpyrrolidone, N-vinyl-5-methylpyrrolidone, N- It may be a polymer containing a derivative having a substituent on the pyrrolidone ring, such as vinyl-3,3,5-trimethylpyrrolidone, N-vinyl-3-benzylpyrrolidone. In addition to the polyvinyl pyrrolidone resin, a polyvinyl alcohol resin, a cellulose derivative, or the like can be mixed and used as the binder resin for the adhesive layer.

  The polyvinylpyrrolidone resin modifier contained in the adhesive layer will be described below. Examples of the modifying agent include resins such as carboxymethyl cellulose, cellulose acetate, cellulose acetate propionate, dibutyl tartrate, dimethyl phthalate, and shellac resin. In the present invention, among the above modifiers, cellulose acetate propionate and shellac resin are particularly preferably used, and in the adhesiveness between the substrate and the dye layer, good adhesiveness is obtained at both normal temperature and high humidity. It is done.

  In the present invention, a polyvinyl pyrrolidone resin modifier is used in order to prevent the polyvinyl pyrrolidone resin from absorbing moisture in the adhesive layer and deteriorating its adhesion to the substrate. The above modifiers may be used in combination of two or more as long as there is no influence of interaction.

  The above modifier is contained at a ratio of 0.5% to 10% with respect to the total solid content of the adhesive layer, and thereby, particularly at high temperature and high humidity, compared with the case of the polyvinylpyrrolidone resin alone. The adhesion between the dye layer and the substrate is improved. When the content of the modifier is less than the above range, the adhesion between the dye layer and the substrate under high temperature and high humidity is lowered, and abnormal transfer or the like is likely to occur. On the other hand, when the content ratio of the modifier is larger than the above range, the adhesion between the dye layer and the substrate at room temperature or the like is lowered.

The adhesive layer is prepared by mixing the above modifier and polyvinyl pyrrolidone resin, and adding or adding additives as necessary to dissolve or disperse water or alcoholic aqueous or organic solvents. And it can form using well-known coating means, such as the reverse roll coating method using the gravure printing method, the screen printing method, and the gravure plate. The adhesive layer thus formed preferably has a coating amount in the range of 0.05 to 0.3 g / m ² when dried. If the coating amount is small, the unevenness of the base material cannot be filled, and an uncoated part is generated, and this part becomes a trigger, and abnormal transfer occurs in which the dye layer is taken on the receiving layer side of the image receiving sheet during thermal transfer. Cheap. On the other hand, when the coating amount of the adhesive layer is larger than the above range, the adhesive layer and the dye layer are easily mixed during the dye layer coating, and the receiving layer is easily taken on the dye layer side during the thermal transfer.

(Dye layer)
In the thermal transfer sheet of the present invention, the dye layer 3 is provided on the other surface of the base material provided with a heat-resistant slipping layer on one surface via an adhesive layer. The dye layer may be composed of a single layer of one color, or a plurality of dye layers containing dyes having different hues may be repeatedly formed on the same surface of the same substrate in the surface order. The dye layer is a layer formed by supporting a heat transfer dye with an arbitrary binder. As the dye to be used, a dye that melts, diffuses or sublimates by heat, and is used in a conventionally known sublimation transfer type thermal transfer sheet can be used in the present invention. The selection is made in consideration of printing sensitivity, light resistance, storage stability, solubility in a binder, and the like.

  Examples of the dye include azomethines such as diarylmethane, triarylmethane, thiazole, merocyanine, pyrazolone methine and the like, indoaniline, acetophenone azomethine, pyrazoloazomethine, imidazolazomethine, imidazoazomethine, and pyridone azomethine. , Xanthene, oxazine, dicyanostyrene, cyanomethylene represented by tricyanostyrene, thiazine, azine, acridine, benzeneazo, pyridoneazo, thiophenazo, isothiazoleazo, pyrroleazo, pyralazo, imidazoleazo, Azos such as thiadiazole azo, triazole azo, dizazo, spiropyran, indolinospiropyran, fluoran, rhodamine lactam, naphthoquinone, anne Rakinon system include the quinophthalone like.

  As the binder for the dye layer, any conventionally known resin binder can be used. Examples of preferred binders include cellulose resins such as ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, and butyric acid cellulose. , Polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl pyrrolidone, polyacrylamide and other vinyl resins, polyester resins and phenoxy resins. Among these, cellulose resins, acetal resins, butyral resins, polyester resins, phenoxy resins, and the like are particularly preferable from the viewpoints of heat resistance, dye migration, and the like.

  In the present invention, the following releasable graft copolymer can be used as a release agent or binder in place of the resin binder. This releasable graft copolymer is obtained by graft polymerizing at least one releasable segment selected from a polysiloxane segment, a fluorocarbon segment, a fluorinated hydrocarbon segment, or a long-chain alkyl segment on a polymer main chain. Is. Among these, a graft copolymer obtained by grafting a polysiloxane segment to a main chain made of a polyvinyl acetal resin is particularly preferable.

The dye layer may contain the above-mentioned dyes, binders, and other various conventional additives as required. Examples of the additive include organic fine particles such as polyethylene wax and inorganic fine particles in order to improve releasability from the image receiving sheet and ink coating suitability. Such a dye layer is usually prepared by adding the above-mentioned dye, binder, and additives as necessary in an appropriate solvent, and dissolving or dispersing each component to prepare a coating solution. It can be formed by applying and drying the liquid on a substrate. As this coating method, known means such as a gravure printing method, a screen printing method, a reverse roll coating method using a gravure plate, or the like can be used. The dye layer thus formed has a coating amount at the time of drying of about 0.2 to 6.0 g / m ² , preferably about 0.3 to 3.0 g / m ² .

(Heat resistant slipping layer)
In the thermal transfer sheet of the present invention, a heat-resistant slipping layer 4 is provided on one surface of the substrate in order to prevent adverse effects such as sticking and printing wrinkles due to the heat of the thermal head. The resin for forming the thermal slipping layer may be any conventionally known resin, for example, polyvinyl butyral resin, polyvinyl acetoacetal resin, polyester resin, vinyl chloride-vinyl acetate copolymer, polyether resin, Polybutadiene resin, styrene-butadiene copolymer, acrylic polyol, polyurethane acrylate, polyester acrylate, polyether acrylate, epoxy acrylate, urethane or epoxy prepolymer, nitrocellulose resin, cellulose nitrate resin, cellulose acetate propionate resin, cellulose Acetate butyrate resin, cellulose acetate hydrodiene phthalate resin, cellulose acetate resin, aromatic polyamide resin, polyimide resin, polyamideimide resin, poly Boneto resins, and chlorinated polyolefin resins.

  The slipperiness imparting agent added to or overcoating the heat resistant slipping layer made of these resins includes phosphate ester, silicone oil, graphite powder, silicone graft polymer, fluorine graft polymer, acrylic silicone graft polymer, acrylic siloxane, aryl Examples thereof include silicone polymers such as siloxane, but a layer made of a polyol, for example, a polyalcohol polymer compound, a polyisocyanate compound, and a phosphate ester compound, and it is more preferable to add a filler.

The heat-resistant slipping layer is prepared by dissolving or dispersing the above-described resin, slipperiness-imparting agent, and filler in an appropriate solvent on the base sheet to prepare a heat-resistant slipping layer coating solution. This can be formed by coating with a forming means such as gravure printing, screen printing, reverse roll coating using a gravure plate, and drying. The coating amount of the heat-resistant slip layer is a ^{solid, 0.1g / m 2 ~3.0g / m} 2 is preferred.

Next, the present invention will be described in further detail with reference to Examples , Reference Examples and Comparative Examples. In the text, “part” or “%” is based on mass unless otherwise specified. The adhesive layer coating solution having the following composition is dried on the untreated polyethylene terephthalate film (PET) (Mitsubishi Chemical Polyester Film Co., Ltd., Diafoil K880) having a thickness of 4.5 μm by gravure coating. It apply | coated so that an application quantity might be 0.06 g / m < ² >, and it dried at 110 degreeC for 1 minute, and formed the contact bonding layer.

Further, on the adhesive layer, a dye layer coating solution having the following composition was applied by gravure coating so that the dry coating amount was 0.8 g / m ² and dried to form a dye layer. A thermal transfer sheet is prepared. In addition, a heat resistant slipping layer coating solution having the following composition is applied to the other surface of the base material in advance by gravure coating and dried so that the dry coating amount becomes 1.0 g / m ² . A layer was formed.

<Adhesive layer composition A>
Polyvinylpyrrolidone resin (K-90, manufactured by ISP Ltd.) 9.9 parts Shellac resin (Rack Coat 50, manufactured by Nippon Shellac Co., Ltd.) 0.1 part Methyl ethyl ketone 83 parts Isopropyl alcohol 83 parts

<Dye layer composition liquid 1>
C. I. Solvent Blue 22 5.5 parts Polyvinyl acetal resin 3.0 parts (SREC KS-5 Sekisui Chemical Co., Ltd.)
Methyl ethyl ketone 22.5 parts Toluene 68.2 parts

<Heat resistant slipping layer composition>
13.6 parts of polyvinyl butyral resin (manufactured by SREC BX-1 by Sekisui Chemical Co., Ltd.)
0.6 parts of polyisocyanate curing agent (Takenate D218, Takeda Pharmaceutical Company Limited)
Phosphate 0.8 parts (Plysurf A208S, Daiichi Kogyo Seiyaku Co., Ltd.)
Methyl ethyl ketone 42.5 parts Toluene 42.5 parts

A PET film substrate having the same conditions as in Example 1 was used, and a heat-resistant slipping layer similar to that in Example 1 was previously formed on the other surface of the substrate. An adhesive layer coating solution having the following composition is applied to the surface of the substrate opposite to the surface on which the heat-resistant slip layer is provided by gravure coating and dried to a dry coating amount of 0.06 g / m ^2. Thus, an adhesive layer was formed. Further, a dye layer is formed on the adhesive layer in the same manner as in Example 1 to produce the thermal transfer sheet of Example 2.

<Adhesive layer composition B>
Polyvinylpyrrolidone resin (K-90, manufactured by ISP Ltd.) 9.5 parts Shellac resin (Rack Coat 50, manufactured by Nippon Shellac Co., Ltd.) 0.5 parts Methyl ethyl ketone 83 parts Isopropyl alcohol 83 parts

A PET film substrate having the same conditions as in Example 1 was used, and a heat-resistant slipping layer similar to that in Example 1 was previously formed on the other surface of the substrate. An adhesive layer coating solution having the following composition is applied to the surface of the substrate opposite to the surface on which the heat-resistant slip layer is provided by gravure coating and dried to a dry coating amount of 0.06 g / m ^2. Thus, an adhesive layer was formed. Further, a dye layer is formed on the adhesive layer in the same manner as in Example 1 to produce the thermal transfer sheet of Example 3.

<Adhesive layer composition C>
Polyvinylpyrrolidone resin (K-90, manufactured by ISP Ltd.) 9.0 parts Shellac resin (Rackcoat 50, manufactured by Nippon Shellac Co., Ltd.) 1.0 part Methyl ethyl ketone 83 parts Isopropyl alcohol 83 parts

A PET film substrate having the same conditions as in Example 1 was used, and a heat-resistant slipping layer similar to that in Example 1 was previously formed on the other surface of the substrate. An adhesive layer coating solution having the following composition is applied to the surface of the substrate opposite to the surface on which the heat-resistant slip layer is provided by gravure coating and dried to a dry coating amount of 0.06 g / m ^2. Thus, an adhesive layer was formed. Further, a dye layer is formed on the adhesive layer in the same manner as in Example 1 to produce the thermal transfer sheet of Example 4.

<Adhesive layer composition liquid D>
Polyvinylpyrrolidone resin (K-90, manufactured by ISP Ltd.) 9.9 parts Cellulose acetate propionate resin 0.1 part (CAP 482-0.5, manufactured by E. Kodak Co.)
Methyl ethyl ketone 83 parts Isopropyl alcohol 83 parts

A PET film substrate having the same conditions as in Example 1 was used, and a heat-resistant slipping layer similar to that in Example 1 was previously formed on the other surface of the substrate. An adhesive layer coating solution having the following composition is applied to the surface of the substrate opposite to the surface on which the heat resistant slipping layer is provided by gravure coating and dried to a dry coating amount of 0.05 g / m ^2. Thus, an adhesive layer was formed. Further, a dye layer is formed on the adhesive layer in the same manner as in Example 1 to produce the thermal transfer sheet of Example 5.

<Adhesive layer composition liquid E>
Polyvinylpyrrolidone resin (K-90, manufactured by ISP Ltd.) 9.5 parts Cellulose acetate propionate resin 0.5 part (CAP 482-0.5, manufactured by E. Kodak Co.)
Methyl ethyl ketone 83 parts Isopropyl alcohol 83 parts

(Reference Example 1)
A PET film substrate having the same conditions as in Example 1 was used, and a heat-resistant slipping layer similar to that in Example 1 was previously formed on the other surface of the substrate. The adhesive layer coating solution used in Example 5 was applied to the surface opposite to the surface on which the heat-resistant slipping layer of the substrate was provided by gravure coating so that the dry coating amount was 0.03 g / m ^2. And dried to form an adhesive layer. Further, a dye layer is formed on the adhesive layer in the same manner as in Example 1 to produce the thermal transfer sheet of Reference Example 1 .

A PET film substrate having the same conditions as in Example 1 was used, and a heat-resistant slipping layer similar to that in Example 1 was previously formed on the other surface of the substrate. The adhesive layer coating solution used in Example 5 was applied to the surface of the base material opposite to the surface on which the heat-resistant slip layer was provided by gravure coating so that the dry coating amount was 0.1 g / m ^2. And dried to form an adhesive layer. Further, a dye layer is formed on the adhesive layer in the same manner as in Example 1 to produce the thermal transfer sheet of Example 7.

A PET film substrate having the same conditions as in Example 1 was used, and a heat-resistant slipping layer similar to that in Example 1 was previously formed on the other surface of the substrate. The adhesive layer coating solution used in Example 5 was applied to the surface opposite to the surface on which the heat-resistant slip layer of the substrate was provided, by gravure coating so that the dry coating amount was 0.2 g / m ^2. And dried to form an adhesive layer. Further, a dye layer is formed on the adhesive layer in the same manner as in Example 1 to produce the thermal transfer sheet of Example 8.

A PET film substrate having the same conditions as in Example 1 was used, and a heat-resistant slipping layer similar to that in Example 1 was previously formed on the other surface of the substrate. The adhesive layer coating solution used in Example 5 was applied by gravure coating on the surface opposite to the surface on which the heat-resistant slipping layer of the substrate was provided so that the dry coating amount was 0.25 g / m ^2. And dried to form an adhesive layer. Further, a dye layer is formed on the adhesive layer in the same manner as in Example 1 to produce a thermal transfer sheet of Example 9.

(Reference Example 2)
A PET film substrate having the same conditions as in Example 1 was used, and a heat-resistant slipping layer similar to that in Example 1 was previously formed on the other surface of the substrate. The adhesive layer coating solution used in Example 5 was applied to the surface opposite to the surface on which the heat-resistant slipping layer of the substrate was provided by gravure coating so that the dry coating amount was 0.35 g / m ^2. And dried to form an adhesive layer. Further, a dye layer is formed on the adhesive layer in the same manner as in Example 1 to produce a thermal transfer sheet of Reference Example 2 .

A PET film substrate having the same conditions as in Example 1 was used, and a heat-resistant slipping layer similar to that in Example 1 was previously formed on the other surface of the substrate. An adhesive layer coating solution having the following composition is applied to the surface of the substrate opposite to the surface on which the heat-resistant slip layer is provided by gravure coating and dried to a dry coating amount of 0.06 g / m ^2. Thus, an adhesive layer was formed. Further, a dye layer is formed on the adhesive layer in the same manner as in Example 1 to produce the thermal transfer sheet of Example 11.

<Adhesive layer composition liquid F>
Polyvinylpyrrolidone resin (K-90, manufactured by ISP Ltd.) 9.0 parts Cellulose acetate propionate resin 1.0 part (CAP 482-0.5, manufactured by E. Kodak Co.)
Methyl ethyl ketone 83 parts Isopropyl alcohol 83 parts

(Comparative Example 1)
A PET film substrate having the same conditions as in Example 1 was used, and a heat-resistant slipping layer similar to that in Example 1 was previously formed on the other surface of the substrate. An adhesive layer coating solution having the following composition is applied to the surface of the substrate opposite to the surface on which the heat-resistant slip layer is provided by gravure coating and dried to a dry coating amount of 0.06 g / m ^2. Thus, an adhesive layer was formed. Further, a dye layer is formed on the adhesive layer in the same manner as in Example 1 to produce a thermal transfer sheet of Comparative Example 1.

<Adhesive layer composition liquid G>
Polyvinyl pyrrolidone resin (K-90, manufactured by ISP Ltd.) 10 parts Methyl ethyl ketone 83 parts Isopropyl alcohol 83 parts

(Comparative Example 2)
A PET film substrate having the same conditions as in Example 1 was used, and a heat-resistant slipping layer similar to that in Example 1 was previously formed on the other surface of the substrate. An adhesive layer coating solution having the following composition is applied to the surface of the substrate opposite to the surface on which the heat-resistant slip layer is provided by gravure coating and dried to a dry coating amount of 0.06 g / m ^2. Thus, an adhesive layer was formed. Further, a dye layer is formed on the adhesive layer in the same manner as in Example 1 to produce a thermal transfer sheet of Comparative Example 2.

<Adhesive layer composition liquid H>
Polyvinylpyrrolidone resin (K-90, manufactured by ISP Ltd.) 8.0 parts Shellac resin (Rackcoat 50, manufactured by Nippon Shellac Co., Ltd.) 2.0 parts Methyl ethyl ketone 83 parts Isopropyl alcohol 83 parts

(Comparative Example 3)
A PET film substrate having the same conditions as in Example 1 was used, and a heat-resistant slipping layer similar to that in Example 1 was previously formed on the other surface of the substrate. An adhesive layer coating solution having the following composition is applied to the surface of the substrate opposite to the surface on which the heat-resistant slip layer is provided by gravure coating and dried to a dry coating amount of 0.06 g / m ^2. Thus, an adhesive layer was formed. Further, a dye layer is formed on the adhesive layer in the same manner as in Example 1 to produce a thermal transfer sheet of Comparative Example 3.

<Adhesive layer composition liquid I>
Polyvinylpyrrolidone resin (K-90, manufactured by ISP Ltd.) 8.0 parts Cellulose acetate propionate resin 2.0 parts (CAP 482-0.5, manufactured by E. Kodak Co.)
Methyl ethyl ketone 83 parts Isopropyl alcohol 83 parts (Comparative Example 4)
A PET film substrate having the same conditions as in Example 1 was used, and a heat-resistant slipping layer similar to that in Example 1 was previously formed on the other surface of the substrate. A dye layer is directly formed in the same manner as in Example 1 without providing an adhesive layer on the surface of the substrate opposite to the surface on which the heat-resistant slip layer is provided, and a thermal transfer sheet of Comparative Example 4 is produced.

Using the thermal transfer sheets of Examples , Reference Examples and Comparative Examples prepared above, each evaluation of heat-resistant adhesion at room temperature and high temperature and high humidity and adhesion to an image receiving sheet was performed by the following methods.

(Heat resistant adhesiveness 1)
A thermal transfer sheet as a sample of Examples , Reference Examples and Comparative Examples is pasted on the mount with the dye layer surface facing up (the mount and the heat-resistant slipping layer are in contact with each other). And the reference ribbon 1 corresponding to the sample (the condition of the dye layer is the same, the base material is made by Mitsubishi Chemical Polyester Film Co., Ltd., and the dye layer is provided directly on the easy-foil-treated PET film of Diafoil K230E) Attached to different positions on the same mount with the dye layer surface facing up, the sample and the reference ribbon are folded back so that the dye layer surfaces are in contact with each other, temperature 100 to 130 ° C., pressure 34.3 × 10 Heat sealing was performed at ⁴ Pa and a pressurization time of 2 seconds, both were peeled off, and the remaining state (taken state) of each dye layer of the sample and the reference ribbon 1 was visually examined, and evaluated according to the following criteria. did. However, both the thermal transfer sheet and the reference ribbon 1 as the samples of Examples , Reference Examples and Comparative Examples are subjected to the above heat sealing in a state where they are left at room temperature, and both the thermal transfer sheet and the reference ribbon 1 as the samples are used. Then, after standing in an environment of 40 ° C. and 90% RH for 16 hours, the above-described heat sealing was conducted in two ways.

○: The area of the dye layer remaining on the sample side is larger than the area remaining on the reference ribbon side.
Δ: The area of the dye layer remaining on the sample side is equal to the area remaining on the reference ribbon side.
X: The area of the dye layer remaining on the sample side is smaller than the area remaining on the reference ribbon side.

(Heat resistant adhesion 2)
A thermal transfer sheet as a sample of Examples , Reference Examples and Comparative Examples is pasted on the mount with the dye layer surface facing up (the mount and the heat-resistant slipping layer are in contact with each other). Then, the reference ribbon 2 corresponding to the sample (the conditions of the dye layer are the same, and the base material is a polyvinyl pyrrolidone resin (K-90, ISP) on the surface of a PET film of Diafoil K880 manufactured by Mitsubishi Chemical Polyester Film Co., Ltd. Ltd.) (with the same adhesive layer conditions as those of Comparative Example 1 provided so as to be 0.06 g / m @ 2 when dried) with the dye layer side up, at different positions on the same mount. Attach, fold back each mount so that the sample and the dye layer surface of the reference ribbon are in contact with each other, heat seal at a temperature of 100 to 130 ° C., a pressure of 34.3 × 10 4 Pa, and a pressurization time of 2 seconds, and peel both Then, the residual state (taken state) of each dye layer of the sample and the reference ribbon 2 was visually examined and evaluated according to the same standard as the heat resistant adhesiveness 1 described above. However, when both the thermal transfer sheet and the reference ribbon 2 as the samples of Examples , Reference Examples and Comparative Examples are left to stand at room temperature and the heat seal is performed, both the thermal transfer sheet as the sample and the reference ribbon 2 are used. Then, after standing in an environment of 40 ° C. and 90% RH for 16 hours, the above-described heat sealing was conducted in two ways.

(Adhesiveness with image receiving sheet)
Overlay so that the dye layer surface of each of the thermal transfer sheets obtained in the above Examples , Reference Examples and Comparative Examples is in contact with the image receiving surface of the image receiving sheet of the Olympus Corporation digital color printer P-200 standard set. Heat seal at a temperature of 100 to 130 ° C., a pressure of 34.3 × 10 ⁴ Pa, and a pressurization time of 2 seconds, both are peeled off, and the peeled state of the dye layer of the sample and the image receiving layer of the image receiving sheet is visually examined. Evaluation was made according to the following criteria. In this case, the heat transfer sheet and the image receiving sheet were left to stand at room temperature, and the heat sealing was performed.

○: The image receiving layer is not peeled off on the dye layer side, and there is no abnormality.
X: The image receiving layer is peeled off on the dye layer side.

＊１；変性剤添加量は、ポリビニルピロリドン樹脂（Ｋ−９０、ＩＳＰ Ｌｔｄ．製）と合わせた全体に対する添加量の割合である。但し、固形分基準での割合である。 The evaluation results of the above Examples , Reference Examples and Comparative Examples are shown in Table 1 below.

* 1: The modifier addition amount is the ratio of the addition amount to the whole combined with polyvinylpyrrolidone resin (K-90, manufactured by ISP Ltd.). However, the ratio is based on solid content.

From the above results, the cellulose acetate propionate resin which is a modifier in the adhesive layer contains 5% of the total solid content of the adhesive layer, and the coating amount of the adhesive layer is 0.1 to 0.1% in a dry state. In Examples 7, 8, and 9, which were 0.25 g / m ² , good results were obtained with respect to all of the above heat-resistant adhesiveness 1, 2 and adhesiveness to the image receiving sheet. In Examples 1 to 5 and Example 11, the shellac resin or cellulose acetate propionate resin, which is a modifier, is contained in the adhesive layer in a ratio of 0.5% to 10% with respect to the total solid content of the adhesive layer. The coating amount of the adhesive layer is 0.05 to 0.06 g / m ² in a dry state, but the adhesive property is the same as that of the reference ribbon at room temperature of heat resistant adhesiveness 2, but it is the standard at high temperature and high humidity. The adhesion between the substrate and the dye layer was higher than that of the ribbon. In Reference Example 1 , the modifier contained in the adhesive layer at a ratio of 5% with respect to the total solid content of the adhesive layer, but the coating amount of the adhesive layer was 0.03 g / m ² in a dry state, It was found that the coating amount was too small and the adhesion between the dye layer and the substrate under high temperature and high humidity was lowered. In Reference Example 2 , the adhesive layer contains a modifier at a ratio of 5% with respect to the total solid content of the adhesive layer, but the coating amount of the adhesive layer is 0.35 g / m ² in a dry state. This indicates that the amount of coating is too large, and the receiving layer is easily taken on the dye layer side during thermal transfer, which is considered to be because the adhesive layer and the dye layer are easily mixed when the dye layer is applied.

  In Comparative Example 1, the adhesive layer did not contain any modifier, and it was found that in the heat resistant adhesiveness 1, the adhesiveness between the dye layer and the substrate under high temperature and high humidity was lowered. In Comparative Examples 2 and 3, the modifying agent is contained in the adhesive layer in a proportion of 20% with respect to the total solid content of the adhesive layer, the content of the modifying agent is too large, and the proportion of the linear polymer polyvinylpyrrolidone resin is Therefore, the adhesiveness is lower than that of the reference ribbon at room temperature of heat resistant adhesiveness 2. In Comparative Example 4, a dye layer was directly provided on the base material without providing an adhesive layer. In heat-resistant adhesion, the dye layer and the base material at normal temperature and high temperature and high humidity were used. Adhesion is reduced.

It is a schematic sectional drawing which shows one embodiment which is the thermal transfer sheet of this invention.

Explanation of symbols

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

Claims (1)

In a thermal transfer sheet in which a heat-resistant slipping layer is provided on one surface of the substrate, and an adhesive layer and a dye layer are sequentially formed on the other surface of the substrate, the adhesive layer is used as a polyvinyl pyrrolidone resin and a modifier of the resin. Cellulose acetate propionate or shellac resin is contained, and the modifier is contained at a ratio of 0.5% to 10% with respect to the total solid content of the adhesive layer, and the adhesive layer is dried. thermal transfer sheet coating amount of time is characterized by a 0.05 to 0.3 g / m ^2.

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