JP2006264110A - Image transfer sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image transfer sheet which can easily produce a three-dimensional image on various kinds of articles. <P>SOLUTION: This image transfer sheet comprises an adhesive image layer 3 formed on a protecting layer 2 applied to the surface of a base material 1, wherein the adhesive image layer 3 and the protecting layer 2 being transferred to a transfer surface in one piece. The adhesive image layer 3 is formed by expanding an ink containing a coloring agent, a foaming agent and a pressure-sensitive adhesive. For the foaming agent, a thermal foaming agent which expands by heat can be used. In addition, the adhesive image layer 3 can be formed by expanding the ink stuck to the surface of the protecting layer 2 by an inkjet recording process. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image transfer sheet for forming a three-dimensional image that is raised on various articles.

  Conventionally, image transfer sheets have been used for the purpose of lettering, marking or coloring. This image transfer sheet is configured by applying a release agent on a substrate such as paper or film, printing characters or designs on it with ink, and further applying a pressure sensitive adhesive on it. The character, design, etc. are pressure-sensitively transferred to the transfer target (see, for example, Patent Document 1). The characters and pictures transferred in this way are of a substantially flat shape with no bulge, as in a normal print image, but in recent years, stereoscopic images made up of bulges of pictures and characters have become increasingly popular, and lettering There is an increasing demand for forming a stereoscopic image on an article to be marked.

  As a method for forming a stereoscopic image, for example, an ink containing an alcohol-soluble resin that is thermally expanded by heating is used, and a desired dot image is formed on a recording medium by an inkjet recording method, and the dot image is heated to There is a method in which ink is fixed and dried on a recording medium and thermally expanded (see Patent Document 2).

  However, since the three-dimensional image forming method of Patent Document 2 performs ink jet recording directly on the surface on which a three-dimensional image is to be formed, a three-dimensional image can be formed by this method on paper or film to which ink jet recording can be applied. It is limited to such a relatively thin sheet. On the other hand, there are a wide variety of recording media for which formation of a stereoscopic image is desired, and the method of Patent Document 2 cannot sufficiently meet the demand for forming a stereoscopic image.

Japanese Patent Publication No. 2-48440 JP 2001-115199 A

  Accordingly, an object of the present invention is to provide an image transfer sheet capable of easily forming a stereoscopic image on various articles.

  The present invention is an image transfer sheet having an adhesive image layer on a protective layer provided on a substrate, and the adhesive image layer and the protective layer are integrally transferred to a transfer surface. The above adhesive image layer achieves the above object by providing an image transfer sheet formed by foaming an ink containing a colorant, a foaming agent and a pressure sensitive adhesive.

  According to the image transfer sheet of the present invention, it is possible to easily transfer a raised three-dimensional image regardless of whether the surface to be transferred is flat, concave or convex, and it is suitable for decoration of various articles, formation of Braille, etc. Can be used for In addition, since the surface of the stereoscopic image obtained by using the present invention is covered with a protective layer, the texture of the image surface such as a glossy tone, a raster tone, or a matte tone can be selected by appropriately selecting the protective layer. Can be freely changed, and various design expressions are possible. Further, it is difficult to turn over due to friction. Furthermore, it is excellent in light resistance, gas resistance and water resistance, and can be stored for a long time.

  The image transfer sheet of the present invention has an adhesive image layer on a protective layer provided on a substrate. Below, each structural member (a base material, a protective layer, an adhesive image layer) of the image transfer sheet of this invention is demonstrated.

  As the substrate according to the present invention, paper such as glassine paper or parchment paper, a plastic film or a sheet can be used. Preferred substrates are plastic films or sheets, such as polyethylene terephthalate (PET), biaxially oriented polypropylene (OPP), polyethylene naphthalate (PEN), polyphenyl sulfide (PPS), polyethersulfone (PES), polystyrene. Examples thereof include a film or sheet formed from a material such as (PS) or polypropylene (PP). Among these, an OPP film or sheet subjected to corona discharge treatment, a PET film or a sheet is preferably used as a substrate in the present invention because of excellent coating stability.

  The substrate can be appropriately selected depending on the texture of the protective layer after transfer. For example, when a base material having a high smoothness (surface glossiness) on the surface on which the protective layer is formed (protective layer forming surface) is selected as the base material, the protection facing the protective layer forming surface The smoothness of the layer surface (the surface that becomes the outermost surface after transfer) is enhanced, and as a result, it is possible to form a glossy stereoscopic image with excellent gloss. In addition, when a base material with a roughened protective layer surface and a low smoothness (surface glossiness) is selected as the base material, the smoothness of the surface of the protective layer is lowered, resulting in a glossiness. An adjusted matte (matte) tone or raster tone stereoscopic image can be formed. As a method for roughening the substrate, there are an embossing method, a method in which inorganic particles such as silica and titania are contained in the substrate, and a method in which the inorganic particles are sprayed on the protective layer forming surface of the substrate.

  The thickness of the base material is preferably 100 to 250 μm from the viewpoint of ensuring transportability in the printer.

  A release agent is preferably applied to the protective layer-forming surface of the base material for the purpose of facilitating peeling of the protective layer. As the release agent, a release agent usually used in this type of transfer sheet can be used. For example, plant waxes such as carnauba wax, auricule wax, sugarken wax, rice wax, paraffin wax, polyethylene Examples thereof include wax, acrylic resin, silicone resin, fluorine resin, melamine resin, colloidal silica, and the like, and these can be used alone or in combination of two or more.

  The protective layer according to the present invention is preferably composed mainly of a resin. Examples of the resin that forms the protective layer include acrylic copolymers, acrylic-styrene copolymers, acrylic-urethane copolymers, vinyl acetate resins, vinyl acetate copolymers, vinyl chloride-vinyl acetate copolymers, and chlorides. A vinyl-acrylic copolymer, a vinyl acetate-acrylic copolymer, an acrylic-silicone copolymer, and the like can be mentioned. One of these can be used alone, or two or more can be used in combination.

  Various additives such as UV absorbers, light stabilizers, antioxidants, water-resistant agents, preservatives, thickeners, fluidity improvers, pH adjusters, leveling agents, etc., are added to the protective layer as components other than the resin. An agent can be appropriately contained. Moreover, although the said protective layer is normally transparent, coloring agents, such as dye and a pigment, can be contained in a protective layer and a protective layer can also be colored in a desired color.

  The thickness of the protective layer is preferably 10 to 40 μm from the viewpoint of ensuring image protection characteristics such as water resistance, light resistance, gas resistance, and abrasion resistance, and realizing a good texture of a stereoscopic image.

The adhesive image layer according to the present invention is formed by foaming ink containing colorants, foaming agents, and pressure-sensitive adhesives as essential components. The ink only needs to contain at least these three components, and may be water-based ink or oil-based ink, but is preferably water-based ink containing water as a main solvent in addition to these three components. Such an aqueous ink is particularly suitable for an ink jet recording system.
Hereinafter, the ink which is a material for forming the adhesive image layer according to the present invention will be described.

  As the colorant, a dye and / or a pigment can be used. Examples of the dye include water-soluble acid dyes, direct dyes, and reactive dyes described in the color index, but are not limited thereto.

  Examples of the pigment include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments), polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments). , Dioxazine pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.), organic pigments such as nitro pigments, nitroso pigments, aniline black; carbon blacks (eg furnace black, thermal lamp black, acetylene black, channel black, etc.), Inorganic pigments such as metal oxides, metal sulfides, and metal chlorides; extender pigments such as silica, calcium carbonate, and talc can be used. Examples of pigments for yellow ink include C.I. I. Pigment yellow 74, 93, 109, 110, 128, 138, 150, 151, 154, 155, 180, 185 and the like. Examples of pigments for magenta ink include C.I. I. Pigment red 122, 202, 209 and C.I. I. Pigment violet 19 and the like. Examples of the pigment for cyan ink include C.I. I. Pigment blue 15: 3, 15: 4, 60 and the like. Examples of pigments used for color inks other than yellow, cyan, and magenta include C.I. I. Pigment green 7 (phthalocyanine green), 10 (green gold), 36, 37; C.I. I. Pigment brown 3, 5, 25, 26; I. Pigment orange 1, 2, 5, 7, 13, 14, 15, 16, 34, 36, 38 and the like.

  The content of the colorant (dye and / or pigment) is preferably 0.1 to 20% by weight with respect to the total amount of the ink from the viewpoint of the balance between image density and ink ejection stability in ink jet recording. More preferably, it is 0.5 to 10% by weight.

  The foaming agent is not particularly limited as long as foaming occurs by an operation such as heating and decompression, but a thermal foaming agent that foams by heating is preferable, and among them, a pyrolytic foaming agent and a thermally expandable microcapsule are preferable. preferable.

  Examples of the pyrolytic foaming agent include organic compounds such as azo compounds such as azobisisobutyronitrile, azodicarboxylic acid amide, barium azodicarboxylate, trichloromonofluoromethane, dichloromonofluoromethane, and the like. Hydrazine compounds such as fluorinated alkanes, paratoluenesulfonyl hydrazide, diphenylsulfone-3,3′-disulfonylhydrazide, 4,4′-oxybis (benzenesulfonylhydrazide), allylbis (sulfonylhydrazide), p-toluylenesulfonyl Semicarbazide compounds such as semicarbazide, 4,4′-oxybis (benzenesulfonyl semicarbazide), triazole compounds such as 5-morpholyl-1,2,3,4-thiatriazole, N, N′-dinitrosopentamethylenetetrami And N-nitroso compounds such as N, N′-dimethyl-N, N′-dinitrosoterephthalamide. In addition, as the inorganic pyrolytic foaming agent, ammonium carbonate, ammonium hydrogen carbonate, sodium hydrogen carbonate, ammonium nitrite, sodium borohydride, azides and the like can be used.

  The heat-expandable microcapsule is a foaming agent composed of hollow microspheres that can be expanded and foamed by heating, and includes a core substance inside the outer shell layer. As the outer shell layer, for example, polyvinylidene chloride, vinylidene chloride-acrylonitrile copolymer, polyacrylonitrile, acrylonitrile-methyl acrylate copolymer, or the like can be used. Examples of the core substance include low-boiling hydrocarbons such as ethane, propane, butane, pentane, hexane, and heptane, azodicarbonamide, diazoaminobenzene, azodihexahydroxybenzodinitrile, and 4,4-oxybenzenesulfonyl. Organic foaming materials such as hydrazide, azoisobutylnitrile, dinitrosopentamethylenetetramine, paratoluenesulfonyl hydrazide, or inert gases, active gases such as normal-butane and iso-butane, and the like can be used. The particle size of the thermoplastic microcapsule is preferably about 1 to 20 μm. As a commercially available product, for example, a microsphere series manufactured by Matsumoto Yushi Co., Ltd. can be used.

  The content of the foaming agent is preferably 5 to 30% by weight, more preferably 10 to 20% by weight, based on the total amount of the ink, from the viewpoint of uniformly and stably foaming the foaming agent.

  The pressure-sensitive adhesive may be any resin having pressure-sensitive adhesive properties, and examples thereof include acrylic, rubber-based, silicone-based, rosin-based, urethane-based, and polyvinyl ether-based resins. One kind can be used alone, or two or more kinds can be mixed and used. These resins can be used as any type such as a solvent type, an emulsion type, and a solventless type.

  The content of the pressure-sensitive adhesive is preferably 5 to 20% by weight, more preferably 10 to 15% by weight, based on the total amount of the ink, from the viewpoint of obtaining sufficient adhesive strength.

  If necessary, the pressure-sensitive adhesive may contain a tackifier, an anti-blocking agent, an anti-aging agent, a crosslinking agent, a softening agent, a colorant and other additives in an appropriate ratio.

  Examples of the tackifier include rosin and derivatives thereof, ester gum, polyterpene resin, petroleum hydrocarbon resin, styrene resin, alkylphenol resin, terpene phenol resin, ethylene-vinyl acetate copolymer resin, and the like. .

  Examples of the anti-blocking agent include extender pigments such as silica, titanium oxide, aluminum hydroxide, calcium carbonate, barium sulfate, clay, and talc, and polyoxyethylene surfactants.

  In addition to the above-mentioned three components (colorant, foaming agent, pressure-sensitive adhesive), the ink according to the present invention includes water as a main solvent for water-based inks and various organic compounds as main solvents for oil-based inks. Contains solvent.

  The ink according to the present invention further includes, as additives, surfactants such as amphoteric surfactants and nonionic surfactants (acetylene glycol-based or acetylene alcohol-based surfactants), alcohols, glycols, Water-soluble organic solvents such as glycol butyl ether and pyrrolidone, pigment dispersants, preservatives and fungicides, sugars such as glucose, chelating agents, antioxidants, conductivity regulators, pH regulators, pH buffering agents, viscosity modifiers An agent, a surface tension adjusting agent, an oxygen absorbent and the like can be appropriately contained as necessary.

  The adhesive image layer according to the present invention is formed by adhering ink containing the above-described various components onto the protective layer and causing it to foam. As a method for attaching the ink onto the protective layer, a known printing method such as an ink jet recording method, a gravure printing method, an offset printing method, or the like can be used. Among these, the ink jet recording method is preferably used in the present invention because it does not require a printing plate, can print a high-quality image at high speed, and can easily change the image design. The ink adhesion pattern is an image pattern having a mirror image relationship with an image to be formed on the transfer surface. By transferring such an image pattern, a desired stereoscopic image can be obtained. The ink adhesion amount depends on the printing method, but in the ink jet recording method, the ink discharge amount per dot is preferably 2 to 80 pl / dot.

  Further, the foaming method of the ink is preferably selected as appropriate depending on the type of the foaming agent contained in the ink. For example, when a thermal foaming agent that foams by heating is used as the foaming agent, the ink deposited on the protective layer is heated at a temperature equal to or higher than the foaming start temperature of the thermal foaming agent using an appropriate heating means. Thus, the ink can be foamed.

  In order to produce the image transfer sheet of the present invention, first, a coating solution for the protective layer (a coating solution prepared by dissolving or dispersing the protective layer forming material in an appropriate solvent) is formed on the substrate. It is coated and dried to form a protective layer. The coating liquid can be applied in a conventional manner using a known coating apparatus such as a blade coater, an air knife coater, a bar coater, or a roll coater. Then, a print image is formed on the protective layer thus formed by various printing methods such as an ink jet recording method using the ink, and then the ink is foamed by heating the print image. Thus, the image transfer sheet of the present invention can be produced.

  In the image transfer sheet of the present invention, the adhesive force of the adhesive image layer to the transfer surface (A) from the viewpoint of smoothly transferring the adhesive image layer and the protective layer integrally to the transfer surface. It is important that a relationship (A, B> C) is established in which the adhesive force (B) of the adhesive image layer to the protective layer is greater than the adhesive force (C) of the protective layer to the substrate. In order to satisfy this relationship, an appropriate pressure-sensitive adhesive is selected to give sufficient adhesive force to the adhesive image layer, and the above-mentioned release agent is used on the protective layer forming surface of the substrate. It is effective to moderately reduce the adhesive force between the base material and the protective layer, for example, by performing a mold release treatment.

  FIG. 1 is a schematic cross-sectional view of an embodiment of an image transfer sheet of the present invention. In FIG. 1, 1 is a substrate, 2 is a protective layer, and 3 is an adhesive image layer. In order to use the image transfer sheet of the present invention, the image transfer sheet is pressed from the substrate 1 side while the adhesive image layer 3 is in contact with the surface to be transferred, and the adhesive image layer 3 is pressure-bonded to the surface to be transferred. (See FIG. 2A). Next, by peeling off the substrate 1, the adhesive image layer 3 and the protective layer 2 are integrally transferred to the transfer surface, and the transfer is completed (see FIG. 2B). In this way, a three-dimensional image covered with the protective layer can be formed on the transfer surface. The image transfer sheet of the present invention can be applied to various articles, and can form a three-dimensional image on a transfer surface of various materials such as paper, plastic, wood, metal, ceramics, cloth, and leather. .

  In the present invention, “the adhesive image layer and the protective layer are integrally transferred to the transfer surface” means that the adhesive image layer and the protective layer are completely transferred (after transfer, the substrate 2 (b), the adhesive image layer and the part of the protective layer that contacts the adhesive image layer (adhesive image layer corresponding part), as shown in FIG. In which a portion other than the portion corresponding to the adhesive image layer in the protective layer is not transferred and remains on the substrate side. As shown in FIG. 2B, an image transfer sheet in which a part of the protective layer remains on the substrate side after the transfer has an appropriate interlayer strength of the protective layer by adding inorganic pigment particles to the protective layer. It can be realized by weakening.

  The image transfer sheet of the present invention may have a member other than the above-described substrate, protective layer, and adhesive image layer. For example, the surface of the adhesive image layer (transfer surface) covered with a release sheet having releasability is also included in the present invention. According to such a configuration, it is possible to protect the transfer surface until immediately before use, and in use, it is only necessary to peel off the release sheet, and it does not take time and effort.

  Hereinafter, the present invention will be described more specifically with reference to examples of the present invention and test examples showing the effects of the present invention. However, the present invention is not limited to the examples.

〔Example〕
After applying corona discharge treatment to the entire surface of a 125 μm thick plastic film (Teijin DuPont Film Co., Ltd., Teijin Tetron Film S125) as a base material, a protective layer coating solution having the following composition is applied. It dried and formed the 10-micrometer-thick protective layer. Next, using an ink jet printer (Seiko Epson, EM-900C), an image is printed on the protective layer with an ink having the following composition, and then the printed image is heated at 100 ° C. for 30 seconds to foam the ink. As a result, an adhesive image layer having a thickness of about 500 μm was formed. The ink discharge amount (attachment amount) was 40 to 70 pl / dot. The image transfer sheet thus prepared was used as a sample of the example.

<Composition of coating liquid for protective layer>
・ Acrylic acid ester copolymer 47.6% by weight
(Mobile 8020, Tg-22 ° C, manufactured by Clariant Polymer Co., Ltd.)
・ Acrylic acid ester copolymer 34.7% by weight
(Mobile 790, Tg 102 ° C, manufactured by Clariant Polymer Co., Ltd.)
・ Colloidal silica (Snowtex 30, Nissan Chemical) 16.7% by weight
・ Texanol (CS-12, manufactured by Chisso Corporation) 10.0% by weight

<Ink composition>
・ Coloring agent (carbon black) 5.0% by weight
・ Foaming agent (Matsumoto Microsphere F-30, Matsumoto Yushi Seiyaku) 15.0% by weight
・ Acrylic copolymer (pressure-sensitive adhesive) 11.3% by weight
(Mobile 727, Tg 90 ° C., manufactured by Clariant Polymer Co., Ltd.)
・ Acrylate ester copolymer 2.5% by weight
(Primal LC-40, manufactured by Nippon Makrill Chemical)
・ Glycerin 10.0% by weight
・ Triethanolamine 1.0% by weight
・ Surfactant (Olfin E1010, manufactured by Nissin Chemical Industry Co., Ltd.) 1.0% by weight
・ Pure water 54.2% by weight

[Comparative Example]
In the examples, the image transfer sheet was formed in the same manner as in the examples except that the protective layer was not formed, and the ink was directly adhered and foamed on the base material to form the base material and the adhesive image layer alone. This was prepared and used as a sample for a comparative example.

(Transferability evaluation test)
Plastic, glass, and metal transfer bodies having two types of transfer surfaces, a smooth surface and an uneven surface, are prepared, and each transfer object in each transfer object is prepared using each sample (image transfer sheet). When an image transfer process is performed on the transfer surface, any sample can be transferred smoothly (transferability is good), and a three-dimensional image can be formed on the smooth surface and the uneven surface. It was.

(Image gloss evaluation test)
The 75-degree specular glossiness was measured in accordance with JIS-Z8741 for the 100% duty black solid print portion in the three-dimensional image obtained in the above (transferability evaluation test). Good), 30 or more and less than 40 as B and less than 30 as C, the example was A and the comparative example was C.

(Image abrasion resistance evaluation test)
The surface of the three-dimensional image obtained in the above (transferability evaluation test) is lightly rubbed with a finger and then visually observed, and the image that is not turned or disturbed is A (good image rubbing resistance), image edge In the embodiment, B is a slight turn or a slight disturbance of the image but there is no practical problem, and C is a large turn at the end of the image or the image is extremely dirty. Was A, and the comparative example was C.

It is a cross-sectional schematic diagram of one embodiment of the image transfer sheet of the present invention. It is explanatory drawing of the use condition of the image transfer sheet shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Base material, 2 ... Protective layer, 3 ... Adhesive image layer

Claims (3)

An image transfer sheet having an adhesive image layer on a protective layer provided on a substrate, wherein the adhesive image layer and the protective layer are integrally transferred to a transfer surface,
The adhesive image layer is an image transfer sheet formed by foaming ink containing a colorant, a foaming agent and a pressure-sensitive adhesive.   The image transfer sheet according to claim 1, wherein the foaming agent is a thermal foaming agent that foams when heated. The image transfer sheet according to claim 1 or 2, wherein the adhesive image layer is formed by foaming the ink deposited on the protective layer by an ink jet recording method.