JP2006289934A - Protective layer transferring sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a protective layer transferring sheet which can prevent a rainbow-like interference Moire fringe from occurring in a printed article transferred with a protective layer, is excellent in durability as a protective layer, and furthermore, has good foil cutting properties when the protective layer is thermally transferred. <P>SOLUTION: The protective layer transferring sheet 1 has a constitution in which a release layer 3 and an adhesive layer 4 successively overlie a substrate sheet 2, and the release layer comprises a polyester resin with a polar group. In addition, by incorporating a resin (a polyester resin or the like) with almost no difference in refractive index from that for the polyester resin incorporated in the release layer in the adhesive layer, in a printed article on which the protective layer is transferred, there exists no rainbow-like interference Moire fringe by a reflective light on the interface between the release layer and the adhesive layer, and durability as the protective layer is excellent, and furthermore, the foil cutting properties of the protective layer when the protective layer is thermally transferred is also good. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a protective layer transfer sheet, and in particular, a protective layer can be transferred to a transfer target having a thermal transfer image, etc., and excellent durability can be imparted to the transfer target. The present invention relates to a protective layer transfer sheet which is externally reflected so that unevenness (rainbow-like unevenness) does not occur on the surface.

  Conventionally, as a variety of printing methods for forming an image, the dye in the color material layer is sublimed and diffused by heat and the dye is transferred to the image receiving sheet, and the color material layer is melted and softened by heating. Are widely used for thermal transfer, ink jet, and electrophotography. Among them, thermal sublimation transfer can be dyed with a sublimation dye and a thermal transfer sheet in which a dye layer in which a sublimation transfer dye used as a recording material is melted or dispersed in a binder resin is supported on a base material sheet such as a polyester film. There has been proposed a method of forming various full-color images by superimposing an image receiving sheet on which a receiving layer is formed on a material to be transferred, such as paper or plastic film, and thermally transferring a sublimation dye. In this case, a thermal head of the printer is used as the heating means, and the color dots in which a large number of heating amounts of three colors or four colors are adjusted are transferred to the image receiving sheet by heating for a very short time. The color dots reproduce the full color of the document.

  The image formed in this manner is very clear and excellent in transparency because the color material used is a dye, and thus the resulting image is excellent in reproducibility and gradation of intermediate colors, It is possible to form a high-quality image similar to a conventional image by offset printing or gravure printing and comparable to a full-color photographic image. At present, a thermal transfer recording method is widely used as a simple printing method. Since the thermal transfer recording method can easily form various images, the thermal transfer recording method is used in printed materials that require a relatively small number of printed sheets, such as ID card creation, business photographs, or personal computer printers and video printers. .

  The above heat-sensitive sublimation transfer method can control the amount of dye transferred in dot units according to the amount of energy applied to the thermal transfer sheet, so it is excellent in forming a gradation image, but the formed image is a normal printing ink. Unlike the above, the coloring material is not a pigment, is a dye having a relatively low molecular weight, and has no vehicle, so that it has a disadvantage of poor durability such as light resistance, weather resistance, and abrasion resistance. On the other hand, a protective layer thermal transfer sheet having a thermal transfer resin layer is superimposed on an image obtained by thermal transfer of a sublimation dye, and the thermal transfer resin layer is transferred using a thermal head, a heating roll, etc. A method for forming a protective layer is known.

  As a protective layer transfer sheet, for example, as disclosed in Patent Document 1, the main protective layer and the adhesive layer are peeled from the base sheet in a configuration in which a release layer, a main protective layer, and an adhesive layer are laminated on the base sheet. Then, there are those that are transferred to the transfer target. Further, in Patent Document 2, in a protective layer transfer sheet in which a release layer and an adhesive layer are laminated on a base sheet, the release layer and the adhesive layer are peeled from the base sheet at the time of thermal transfer. It is described that the outermost surface of the transferred protective layer is a release layer.

  When using a protective layer transfer sheet as described above and transferring a protective layer onto an image of a printed matter imaged by thermal transfer, when observed under a fluorescent lamp or the like, A rainbow-like interference fringe (unevenness) caused by an optical path difference of reflected light occurs at the interface, and there is a problem that the quality of the printed matter is lowered. On the other hand, in a configuration in which a release layer and an adhesive layer are laminated on a base sheet, in order to bring the refractive index of the release layer closer to the refractive index of the adhesive layer, an acrylic resin and a styrene monomer are used as the resin constituting the release layer. Has been devised to increase the refractive index of the release layer, such as by copolymerization, but the occurrence of the above-mentioned rainbow-like interference unevenness can be prevented, but the durability of the plasticizer resistance and the like is reduced, functioning as a protective layer There is nothing that can satisfy.

JP-A-11-151867 JP 2004-175035 A

  Therefore, in order to solve the above-described problems, the present invention can prevent the occurrence of rainbow-like interference unevenness in the printed material to which the protective layer is transferred, has excellent durability as a protective layer, and further protects the printed matter. It is an object of the present invention to provide a protective layer transfer sheet having good foil tearability during thermal transfer of layers.

  The invention according to claim 1 is a protective layer transfer sheet in which a release layer and an adhesive layer are sequentially laminated on a base material sheet, wherein the release layer contains a polyester resin having a polar group. In addition, the invention according to claim 2 includes a protective layer in which a release layer and an adhesive layer on the base sheet are sequentially laminated, and a portion on which the protective layer is not provided on the same base sheet, and a dye layer and The heat-meltable ink layer is provided in the surface order.

  The protective layer transfer sheet of the present invention has a structure in which a release layer and an adhesive layer are sequentially laminated on a base sheet, the release layer contains a polyester resin having a polar group, and the adhesive layer contains in the release layer. By including a resin (polyester resin, etc.) that has almost no difference from the refractive index of the polyester resin, the rainbow-like interference caused by the reflected light at the interface between the release layer and the adhesive layer in the printed matter with the protective layer transferred. There is no unevenness, the durability as a protective layer is excellent, and the foil breakability at the time of thermal transfer of the protective layer is also good.

  FIG. 1 is a schematic view showing one embodiment of a protective layer transfer sheet 1 of the present invention, which is a configuration in which a release layer 3 and an adhesive layer 4 are laminated on a base sheet 2. Contains a polyester resin having a polar group. Further, a heat resistant slipping layer 5 is provided on the other surface of the base sheet 2 in order to prevent adverse effects such as sticking and wrinkles due to heat of the thermal head. In this protective layer transfer sheet 1, the peeling layer 3 and the adhesive layer 4 are peeled off from the base material sheet 2 by thermal transfer and transferred as a protective layer 6 to the transfer target. FIG. 2 is a schematic view showing another embodiment of the protective layer transfer sheet 1 of the present invention. On the base sheet, a yellow dye layer (Y), a magenta dye layer (M), a cyan dye layer (C ), A black heat-meltable ink layer (BK), a protective layer 6 in which a release layer and an adhesive layer are sequentially laminated are repeatedly formed on the same substrate sheet in the surface order. FIG. 3 is a schematic view showing another embodiment of the protective layer transfer sheet 1 of the present invention. On the base sheet, a yellow dye layer (Y), a magenta dye layer (M), a cyan dye layer ( C) and a protective layer 6 in which a release layer and an adhesive layer are sequentially laminated are repeatedly formed on the same substrate sheet in the surface order. Not limited to those shown in the figure, a protective layer in which a heat-meltable ink layer such as black, a release layer, and an adhesive layer are sequentially laminated on the same base sheet is repeatedly formed in a surface sequence, or dyes of various hues A layer and / or a heat-meltable ink layer, and a protective layer in which a release layer and an adhesive layer are sequentially laminated can be provided in the surface order.

Each layer constituting the protective layer transfer sheet used in the present invention will be described below.
(Substrate sheet)
As the base material sheet 2 used in the protective layer thermal transfer sheet of the present invention, the same base material as that used in the conventional thermal transfer sheet can be used as it is, and the surface of the sheet is subjected to an easy adhesion treatment. And others can be used and are not particularly limited. However, when using a base sheet that has been subjected to easy adhesion treatment, it is desirable to provide a release layer between the base sheet and the release layer.

  Specific examples of preferable base sheet include, for example, polyethylene terephthalate, polyester including polyethylene naphthalate, polycarbonate, polyamide, polyimide, cellulose acetate, polyvinylidene chloride, polyvinyl chloride, polystyrene, fluororesin, polypropylene, polyethylene, There are plastic films such as ionomers, cellophane, etc., and composite films in which two or more of these are laminated can also be used. Although the thickness of these base material sheets is suitably changed according to material so that the intensity | strength and heat resistance may become appropriate, about 2.5-10 micrometers is preferable normally.

(Release layer)
On the base material sheet, a release layer that makes the transferability of the protective layer formed thereon suitable can be provided. In particular, it is desirable to form a release layer between the base sheet and the release layer when the base sheet is subjected to an easy adhesion treatment. As the resin for forming the release layer, any conventionally known resin having excellent release properties can be used. For example, waxes, silicone wax, silicone resin, silicone-modified resin, fluorine resin, fluorine-modified resin, polyvinyl alcohol , Acrylic resins, acrylic-styrene resins, thermally crosslinkable epoxy-amino resins, and thermally crosslinkable alkyd-amino resins. These release resins can be used alone or as a mixture.

  In the release layer, various fillers can be added to the release resin material as described above. Examples of the filler used include known pigments such as silica, alumina, clay, and talc, and plastic pigments made of thermosetting resins, thermoplastic resins, waxes, and the like. To form a release layer, add a resin as described above and, if necessary, a filler, a crosslinking agent or a catalyst, and prepare a coating solution dissolved or dispersed in a general-purpose solvent such as methyl ethyl ketone, toluene, or isopropyl alcohol. Then, the coating solution is applied and dried on the base material by a conventionally known method such as gravure coating or gravure reverse coating so as to have a thickness (dry basis) of about 0.5 to 5 μm.

(Peeling layer)
The release layer 3 of the present invention is characterized by containing a polyester resin having a polar group. The polyester resin has a structure having polar groups such as sulfonic acid group, amino group, carboxylic acid group, and phosphonic acid group at the terminal or side chain of the polyester resin. The polarizability representing strain is high, and the refractive index is also improved. Specifically, the refractive index of the polyester resin having a polar group is about 1.52 to 1.59. The refractive index in the present invention is measured according to the method described in JIS K 7150. The polyester resin having this polar group has a glass transition temperature of about 60 to 100 ° C. When the glass transition temperature is less than 60 ° C., bleeding of the thermal transfer image tends to occur when the printed material is stored at a high temperature. On the other hand, when the glass transition temperature exceeds 120 ° C., the foil breakability during thermal transfer is lowered.

  The polar group of the polyester resin having a polar group in the release layer will be described in detail below. Examples of the polar group include acid groups such as sulfonic acid, carboxylic acid, and phosphoric acid or metal salts thereof, ammonium salts, hydroxyl groups, tertiary amines or quaternary amines, and pyridine. Examples of the sulfonic acid include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, 5- (4-sulfophenoxy) isophthalic acid and metal salts thereof. . Examples of the carboxylic acid include polycarboxylic acid which is an acid component of the polyester resin, glyceric acid, dimethylolpropionic acid, N, N-diethanolglycine, oxycarboxylic acid such as hydroxyethyloxybenzoic acid, diaminopropionic acid, diaminobenzoic acid, etc. And aminocarboxylic acids and derivatives thereof.

  Examples of phosphoric acid include 5-phosphophenoxyisophthalic acid, 5- (4-carbophenoxy) isophthalic acid and metal salts thereof. Tertiary amine or quaternary amine includes nitrogen-containing alcohols such as N-methyldiethanolamine and 2-methyl-2-dimethylaminomethyl-1,3-propanediol, and hydrochlorides, sulfonates, sulfates, and derivatives thereof. Etc. Examples of pyridine include pyridine ring-containing compounds such as picolinic acid, dipicolinic acid, aminopyridine, diaminopyridine, hydroxypyridine, dihydroxypyridine, aminohydroxypyridine, pyridine dimethanol, pyridinepropanediol, pyridineethanol, and derivatives thereof.

  In order to form the release layer, the resin as described above is dissolved or dispersed in a general-purpose solvent such as methyl ethyl ketone, toluene, isopropyl alcohol, and, if necessary, an ultraviolet absorber, a fluorescent brightening agent, inorganic or organic. A filler component, a surfactant, a release agent, and the like are added to prepare a coating solution, and the coating solution is dried by a method known in the art such as gravure coating and gravure reverse coating (dry basis) 0.5 to 10 μm. More preferably, it is formed by coating and drying so as to be 0.7 to 5.0 μm. The thickness of the release layer is preferably within the above range, and if it is too thin, the durability performance as a protective layer cannot be fully exhibited. If the thickness is too thick, transfer defects such as tailing tend to occur during thermal transfer of the protective layer.

(Adhesive layer)
In the present invention, the protective layer transfer sheet has a structure in which a release layer and an adhesive layer are sequentially laminated on a base sheet. This adhesive layer 4 is provided in order to improve the adhesion of the protective layer (a combination of the release layer and the adhesive layer) in the protective layer transfer sheet, and the adhesion of the protective layer after the transfer to the printed material. As the adhesive layer, any conventionally known heat-sensitive adhesive can be used, but it is more preferably formed from a thermoplastic resin having a glass transition temperature of 50 to 100 ° C., for example, acrylic resin, vinyl chloride-vinyl acetate copolymer From resins with good thermal adhesive properties such as coalesced resin, epoxy resin, polyester resin, polycarbonate resin, butyral resin, polyamide resin, vinyl chloride resin, etc., with a refractive index of about 1.52-1.59, Those having an appropriate glass transition temperature are selected. In the present invention, an adhesive layer using a polyester resin such as a polyester resin or a polycarbonate resin is particularly preferably used because of its high compatibility with the release layer. As the resin constituting the adhesive layer, a resin having almost no difference from the refractive index of the polyester resin contained in the release layer is preferably used. Therefore, the refractive index of the thermoplastic resin contained in the adhesive layer is preferably about 1.52 to 1.59. The difference between the refractive index of the polyester resin having a polar group contained in the release layer and the refractive index of the thermoplastic resin contained in the adhesive layer is preferably ± 0.03. In this way, in the printed matter to which the protective layer has been transferred, the rainbow-like interference unevenness due to the reflected light can be eliminated at the interface between the peeling layer and the adhesive layer.

  By including an ultraviolet absorber in the adhesive layer, it is possible to further improve the light resistance, weather resistance, and the like of the thermal transfer image of the transfer target covered with the protective layer after being transferred. Examples of the ultraviolet absorber include salicylate-based, benzophenone-based, benzotriazole-based, triazine-based, substituted acrylonitrile-based, nickel chelate-based, hindered amine-based and the like, which are conventionally known organic ultraviolet absorbers. In addition, for example, polymers having addition polymerizable double bonds such as vinyl groups, acryloyl groups, and methacryloyl groups, or alcoholic hydroxyl groups, amino groups, carboxyl groups, epoxy groups, isocyanate groups, etc., are introduced into these ultraviolet absorbers. The material is a UV-absorbing resin, and the adhesive layer can be constituted from this UV-absorbing resin.

  In order to form the adhesive layer, the resin as described above is dissolved or dispersed in a general-purpose solvent such as methyl ethyl ketone, toluene, isopropyl alcohol, and, if necessary, an ultraviolet absorber, an antioxidant, a fluorescent brightening agent. Then, an inorganic or organic filler component, a surfactant, a release agent, etc. are added to prepare a coating solution, and the coating solution has a thickness (dry basis) of 0 by a conventionally known method such as gravure coating or gravure reverse coating. It is formed by coating and drying so as to have a thickness of 5 to 10 μm, more preferably 0.7 to 5.0 μm. If the thickness of the adhesive layer is too small, the adhesion of the protective layer to the printed material will be reduced. On the other hand, if the thickness of the adhesive layer is too large, the thermal sensitivity during transfer of the protective layer is lowered.

(Heat resistant slipping layer)
The protective layer transfer sheet is provided with a heat-resistant slipping layer 5 on the back surface of the base sheet, that is, on the surface opposite to the surface on which the protective layer is provided, in order to prevent adverse effects such as sticking and wrinkles due to the heat of the thermal head. Is preferred. The thickness of the heat resistant slipping layer is about 0.1 to 2 μm in terms of solid content.

  The protective layer is transferred using the protective layer transfer sheet of the present invention onto the image of the printed matter formed by transferring the sublimation dye or heat-meltable ink. The thermal transfer sheet used for the image formation consists of a dye layer containing a sublimable dye on the substrate, a colored pigment or dye colorant, a wax, or a resin binder. An ink layer is formed. In the present invention, the above-mentioned protective layer transfer sheet and a thermal transfer sheet having a dye layer and a heat-meltable ink layer are separately prepared and used, or yellow, magenta, cyan, black on the same substrate sheet. Using the same thermal head, the thermal transfer image and the protective layer are replaced with the thermal transfer sheet using the dye layer and / or the heat-meltable ink layer having each hue, etc. and the protective layer provided in the surface order. Without using it, it can be used efficiently by continuous thermal transfer.

  The present invention will be described in more detail with reference to examples. In the text, “part” or “%” is based on mass unless otherwise specified.

  A heat-resistant slipping layer having a solid content of 1 μm is provided on one surface of a base material sheet of a polyethylene terephthalate film having a thickness of 4.5 μm, and a release layer coating liquid having the following composition is provided on the other surface of the base material sheet. Was applied by gravure coating to a thickness of 1.5 μm when dried, and dried to form a release layer. Furthermore, on the release layer, using an adhesive layer coating solution having the following composition, it was applied by gravure coating to a thickness of 1.5 μm when dried, and dried to form an adhesive layer. Thus, a protective layer transfer sheet of Example 1 was produced.

(Release layer coating solution)
20 parts of polyester resin having sodium sulfonate group (Toyobo Co., Ltd., Byron 885, refractive index 1.55)
Methyl ethyl ketone 40 parts Toluene 40 parts

(Adhesive layer coating solution)
Polyester resin A (resin composition prepared under the conditions shown below, Tg = 92 ° C., viscosity average molecular weight = 5,000, refractive index 1.55, and this polyester resin A has no polar group. 16 parts Benzophenone UV-absorbing resin 4 parts (BASF Japan, UVA635L)
2 parts of benzotriazole ultraviolet absorber (manufactured by Ciba Specialty Chemicals Co., Ltd., TINUVIN900)
Methyl ethyl ketone 39 parts Toluene 39 parts

(Preparation of resin composition)
Ethylene glycol 10 mol%
90% by mole of tricyclodecane dimethanol
Terephthalic acid 50 mol%
Isophthalic acid 50 mol%
Polyester resin A comprising the above components was prepared by a conventional method.

A protective layer transfer sheet of Example 2 was produced in the same manner as in Example 1 except that the adhesive layer coating solution used in Example 1 was changed to one having the following composition.
(Adhesive layer coating solution)
10 parts of vinyl chloride / vinyl acetate copolymer resin (manufactured by Nissin Chemical Industry Co., Ltd., Solvein CNL, refractive index 1.53)
10 parts of benzophenone UV-absorbing resin (BASF Japan, UVA635L)
Methyl ethyl ketone 40 parts Toluene 40 parts

(Comparative Example 1)
A protective layer transfer sheet of Comparative Example 1 was produced in the same manner as in Example 1 except that the release layer coating solution used in Example 1 was changed to one having the following composition.
(Release layer coating solution)
20 parts of polymethyl methacrylate resin (Mitsubishi Rayon Co., Ltd., Dianar BR-87, refractive index 1.49)
Methyl ethyl ketone 40 parts Toluene 40 parts

(Comparative Example 2)
A protective layer transfer sheet of Comparative Example 2 was produced in the same manner as in Example 1 except that the release layer coating solution used in Example 1 was changed to one having the following composition.
(Release layer coating solution)
20 parts of styrene-modified methyl methacrylate resin (Mitsubishi Rayon Co., Ltd., Dianar BR-50, refractive index 1.56)
Methyl ethyl ketone 40 parts Toluene 40 parts

(Comparative Example 3)
A protective layer transfer sheet of Comparative Example 3 was produced in the same manner as in Example 1 except that the release layer coating solution used in Example 1 was changed to one having the following composition.
(Release layer coating solution)
Polyester resin A having no polar group (used in the adhesive layer coating solution of Example 1 above. Refractive index 1.55) 20 parts Methyl ethyl ketone 40 parts Toluene 40 parts

(Thermal transfer image receiving sheet and protective layer transfer sheet used)
Canon sublimation transfer printer (compact photo printer) CP-200 dedicated image receiving paper and ink ribbon (thermal transfer sheet) were used. However, the protective layer transfer sheet having the conditions shown in the above examples and comparative examples was attached to the overcoat portion of the ink ribbon and changed.

(Printing conditions)
Using a sublimation transfer printer CP-200 manufactured by Canon Inc., a black solid image is formed by solid printing of three colors of yellow, magenta, and cyan using the thermal transfer image receiving sheet and the thermal transfer sheet. A protective layer was transferred to the entire surface to form a printed matter.

(appearance)
Each printed matter with the above protective layer transferred is observed under a three-wavelength tube fluorescent lamp, and examined with the naked eye whether or not rainbow-like interference fringes (unevenness) are caused by reflected light. evaluated.
◯: No rainbow-like interference fringes (unevenness) are observed in appearance, the surface gloss is high, and the quality of the printed material is good.
X: On the appearance, rainbow-like interference fringes (unevenness) are generated, and the quality of the printed matter is low.

(Plasticizer resistance)
A plasticized soft vinyl chloride sheet (Mitsubishi Chemical Co., Ltd. Altron # 480, 400 μm thick) and the protective layer transfer surface of the printed material are overlapped, and a load of 40 g / cm ² is applied for 60 hours in a 50 ° C. environment. The state of deterioration of the image due to the plasticizer was stored and visually observed, and the plasticizer resistance of the protective layer was evaluated according to the following criteria.
○: Not affected by the plasticizer at all and the image is good Δ: Part of the image deteriorates due to the influence of the plasticizer ×: Deterioration occurs on the entire image

The results of the above-described appearance evaluation and plasticizer resistance evaluation are shown in Table 1.

It is the schematic which shows one Embodiment of the protective layer transfer sheet of this invention. It is the schematic which shows other embodiment of the protective layer transfer sheet of this invention. It is the schematic which shows other embodiment of the protective layer transfer sheet of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Protective layer transfer sheet 2 Base material sheet 3 Peeling layer 4 Adhesive layer 5 Heat resistant slipping layer 6 Protective layer

Claims (2)

  A protective layer transfer sheet in which a release layer and an adhesive layer are sequentially laminated on a substrate sheet, wherein the release layer contains a polyester resin having a polar group. A protective layer obtained by sequentially laminating a release layer and an adhesive layer on the base sheet, and a dye layer and / or a heat-meltable ink layer on the same base sheet where no protective layer is provided. The protective layer transfer sheet according to claim 1, wherein the protective layer transfer sheet is provided.

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