JP2011093226A - Thermal transfer sheet and printed matter using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems such as occurrence of jamming and wrinkle during printing, migration of a dye to a protective layer, blocking with time and color change of a printed matter occurs in the lapse of time, which are caused by the amount of remaining solvent in the protective layer of a thermal transfer sheet. <P>SOLUTION: The thermal transfer sheet is constituted by providing, on one surface of a base material, at least a yellow dye layer, a magenta dye layer and a cyan dye layer as a sublimation system thermosensitive ink layer, the protective layer and a sensor layer in a longitudinal direction in a surface sequential order with repetition. In the thermal transfer sheet, the protective layer has one or more layers and remaining solvent mass in the protective layer is 0.001 to 9.000 wt.% toward mass of the protective layer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a thermal transfer sheet for use in a printed matter with a protective layer obtained by a transfer method, and particularly relates to a transfer sheet using a sublimation dye and the printed matter.

  The thermal transfer sheet described above is also called a thermal ribbon (hereinafter referred to as a ribbon). For example, a thermal ink layer and, if necessary, a thermal transfer protective layer (hereinafter referred to as a protective layer), a sensor layer, The heat-resistant slip layer (back coat) is provided on the other surface. Using such a thermal transfer sheet, predetermined heating is performed from the thermal head of the thermal printer, and a part of the thermal ink layer is melted and transferred to the transfer medium side, or the sublimation dye in the thermal ink layer is sublimated. Then, by transferring to the transfer medium side, predetermined thermal transfer recording, that is, printing is performed.

  At present, the thermal transfer recording system has advanced functions of thermal printers, and various images can be recorded easily. Therefore, cards such as ID cards, amusement output products, and images to KIOSK printers by the spread of digital cameras. Widely used for recording information. Under such circumstances, there is a growing demand for stability and durability of the transfer image recording medium obtained by the thermal transfer recording method, and in recent years, the transfer image recorded using the thermal transfer sheet is protected so as to cover it. Many layers are provided to improve the durability of the transferred image recording medium.

  When a transfer image obtained by the thermal transfer recording method using a thermal transfer sheet is exposed to sunlight or illumination light for a long time, the transfer image portion fades due to the influence of ultraviolet rays or ozone in the atmosphere, and recording is not possible. It becomes unclear and becomes a problem. Therefore, in order to impart fading resistance to the recorded transfer image, a method of providing a protective layer on the transferred image by a thermal transfer recording method using a thermal transfer sheet having a protective layer containing an ultraviolet absorber has been conventionally used. There are many cases.

  Further, when a sublimation dye is used, gradation is more clearly expressed and a photographic-like image is obtained as compared with an image using a pigment system. However, because of the dye, if the image is exposed to the surface as it is, various effects such as the effects of ozone, light resistance, scratch resistance (surface protection), chemical resistance, oil resistance, solvent resistance, etc. The problem remains. Therefore, the importance of the protective layer increases.

  Further, the protective layer is transparent, and from the viewpoint of resistance such as the above-mentioned functions, transferability, and surface protection properties, the protective layer is generally provided with a transparent protective layer and may be thicker than the ink layer. Therefore, a large amount of residual solvent remains, which often affects various physical properties. Due to the large amount of residual solvent, the dye moves to the protective layer during storage, jamming and wrinkles such as sticking to the head due to the thermal pressure of the printer head during printing, and also in the printed matter after printing The image may be blurred due to transfer of the dye to the protective layer, and color change with time may occur.

  Patent Document 1 refers to jamming and wrinkles during transfer of the protective layer, although it relates to holograms as an application. However, this document tries to solve the problem by mixing a filler in a layer called an adhesive layer, which is different from the present invention.

Patent Document 2 mentions the weight ratio of a plurality of solvents to be used, but does not specify the residual solvent. Moreover, it is description of the solvent regarding dye, and also uses a solvent having a lower evaporation rate than that of methyl ethyl ketone and regulates the ratio, and does not define the residual solvent in the protective layer. In Patent Document 2, there is a regulation of the weight% of methyl ethyl ketone, but depending on the drying conditions, it may cause whitening of the surface. Although it is similar to the present invention in terms of solvent management, the point of interest is completely different in terms of residual solvent.

  In the case of Patent Document 3, it is clearly stated that an aromatic solvent is used to mitigate the irritating odor caused by an organic solvent. However, it particularly relates to image receiving paper, and furthermore, the evaluation is also a sensory evaluation. It is not limited to the use of aromatics. Of course, the present invention is similar in terms of the solvent to be coated, but is completely different in terms of use and effect.

  In Patent Document 4, a part of the residual solvent in the protective layer is also mentioned, but there is no mention of a specific regulation of the residual solvent amount and an adverse effect caused thereby. Rather, in order to maintain the light resistance necessary for the protective layer, by limiting the type and resin of the light proof agent main skeleton, the plasticity of the resin, the amount of residual solvent does not change, the present invention, The meaning is different.

In the thermal transfer sheet of the present invention, a protective layer is indispensable, particularly when sublimation dyes are used, because the various resistances described above are weaker than pigments. In the present invention, it is designed so that the effect of using a sublimation dye can be maximized when it is in the state of a thermal transfer sheet or printed matter.
In the present invention, the scope of the invention also includes the case where the protective layer as shown in FIG. 1 is one layer or the protective layer as shown in FIG. For example, FIG. 2 assumes a case of three-layer lamination, in which case the first layer is described as a release layer, the second layer is a release layer, and the third layer is an adhesion layer in the order of lamination of the base sheet.

JP 2005-104043 A Japanese Patent Laid-Open No. 5-77567 Japanese Patent Laid-Open No. 7-25172 JP 2003-136644 A

  The present invention relates to a thermal transfer sheet using a sublimation dye and a protective layer for images formed by various image recording apparatuses using the thermal transfer sheet. Thermal transfer sheet that does not cause jamming, wrinkles, dye transfer to the protective layer over time, blocking, color change of the printed matter over time due to the amount of residual solvent in the protective layer of the thermal transfer sheet, and printing using the same Offer things.

  The invention according to claim 1 of the present invention includes a yellow dye layer, a magenta dye layer, a cyan dye layer, a protective layer, and a sensor layer as at least a sublimation thermal ink layer on one surface of a substrate. In the thermal transfer sheet, the protective layer includes one or more layers, and the residual solvent mass in the protective layer is 0. 0 relative to the mass of the protective layer. It is a thermal transfer sheet characterized by being 001 wt% or more and 9.000 wt% or less.

  The invention according to claim 2 of the present invention is a printed matter produced using the thermal transfer sheet according to claim 1.

In the present invention, the present invention relates to a protective layer for images formed by various image recording devices with a thermal transfer sheet using a sublimation dye, and by defining the range of the residual solvent amount in the protective layer of the thermal transfer sheet, As described above, this invention is extremely effective for abnormal transfer during printing (jamming, wrinkles), dye transfer to the protective layer during storage (back-to-back transfer), winding blocking, and prevention of color change over time of prints. is there.

It is sectional drawing which shows an example in case the protective layer of the thermal transfer sheet of this invention is one layer. It is sectional drawing which shows an example in case the protective layer of the thermal transfer sheet of this invention is two layers.

Hereinafter, the thermal transfer sheet of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a case where the protective layer of the thermal transfer sheet according to the present invention is a single layer, and FIG. 2 shows a case where the protective layer has two layers. When the protective layer of FIG. 1 is a single layer, the entire layer is transferred. In FIG. 2, three layers are laminated, but two layers are transferred and protected from the top other than the first layer on the base sheet side 1. Become a layer. When the protective layer as shown in FIG. 1 is a single layer, a thermal ink layer (yellow) 3, a thermal ink layer (magenta) 4, a thermal ink layer (cyan) 5 and a sensor layer are formed on one surface of the base sheet 1. 10 are sequentially provided in the longitudinal direction, and further one protective layer is sequentially provided. The protective layer is transferred from the base sheet 1 to become a protective layer.

  Further, the case where the protective layer in FIG. 2 has two layers will be described. FIG. 2 shows a schematic cross-sectional configuration when the protective sheet has two layers on the base sheet 1. In this thermal transfer sheet, a thermal ink layer (yellow) 3, a thermal ink layer (magenta) 4, a thermal ink layer (cyan) 5, and a sensor layer 10 are sequentially provided on one surface of the base sheet 1 in the longitudinal direction. The release layer 7, the release layer 8, and the adhesive layer 9 from the base sheet 1 are provided on one surface of the base sheet 1 in the protective layer portion, and the release layer 7 is attached to the base sheet at the time of thermal transfer. The release layer 8 and the adhesive layer 9 are transferred to the protective layer while remaining on the 1 side.

  As an example, the case where there are two protective layers in FIG. 2 will be described in detail. As the substrate sheet 1, a material having excellent heat resistance and strength that is not softened and deformed by heat pressure during thermal transfer recording is used. Specifically, polyethylene terephthalate, polyethylene naphthalate, polypropylene, cellophane, acetate, polycarbonate, polysulfone, polyimide, polyvinyl alcohol, aromatic polyamide, aramid, polystyrene, etc., synthetic resin film, condenser paper, paraffin paper, etc. Paper or the like can be used alone or in combination. Among these, a polyethylene terephthalate film is preferably used in consideration of physical properties, processability, cost, and the like. The thickness may be about 2 to 50 μm in consideration of operability and workability, but is more preferably about 2 to 15 μm in consideration of handling properties such as transfer suitability and workability. If necessary, an easy adhesion treatment or the like may be applied to the front and back surfaces of the base sheet.

  The heat-resistant slip layer 2 is particularly necessary when a thermal head is used as a heating means at the time of thermal transfer recording, and is positioned on the back surface when the thermal transfer sheet is wound with a roll so that the thermal head is not fused. It is provided so as not to stick to the protective layer and the thermal ink layer to be adhered, or to prevent migration of the dye in the thermal ink layer, and has heat resistance and releasability. Of course, head wear is also taken into consideration.

  As a constituent material of the heat resistant slipping layer 2, for example, a coating liquid prepared by blending a functional additive imparting releasability and slipperiness, a binder, a curing agent, a solvent, and the like may be used. The thickness may be about 0.1 to 5 μm in terms of dry film thickness.

  Examples of the coating solution for the heat resistant slipping layer 2 include acrylic resins, polyesters, polyurethanes, polyacetals, polyamides, polyimides and the like, or synthetic resins such as isocyanate compounds, epoxy curing agents, phenol curing agents. And a cured coating film comprising a composition to which a melamine curing agent or the like is added or a photocurable resin. Furthermore, the cured coating film which consists of what added release agents, such as a fluorine type, a silicone type, an alkyl type, an acrylic type, or the thing which copolymerized silicone can also be mentioned. Further, a filler may be added to the heat resistant slipping layer as necessary. Examples of the filler to be added include silicone or fluorine powder, silica and resin powder, talc, calcium carbonate, resin filler, natural minerals such as montmorillonite, and flake-like filler.

  As a coating method of the coating liquid constituting the heat resistant slipping layer 2, a conventionally known thin film forming method such as a roll coating method, a screen printing method, a spray method, a gravure printing method and the like which are used in the normal thin film formation is used. It is possible. The optimum thickness varies depending on the type of coating liquid, the processing machine, and the processing conditions, and is not particularly limited. Specifically, the thickness after drying may be about 0.1 to 5 μm, preferably 0.5 to 3 μm. When the thickness is less than 0.1 μm, it is difficult to form a uniform coating film, and sufficient heat resistance may not be obtained.

  On the other hand, the thermal ink layers 3, 4, and 5 are layers formed by supporting a dye with an arbitrary binder resin. As the dye, any of conventionally known dyes used in sublimation thermal ink layers can be used, and is not particularly limited. Further, the ten sensor layers do not need thermal transfer properties, and are only a landmark in a sense that is necessary for managing the start-up of the printer device. The resin layer is a resin mixed with carbon or the like, and its transmission density is detected by the printer. It is sufficient if there is a concentration to be used.

  For example, a sublimable disperse dye is preferably used as the dye contained in the constituent material of the sublimation thermal ink layer. Specifically, examples of the yellow component include Solvent Yellow 56, 16, 30, 93, 33, Disper Yellow 201, 231, 33, and the like. As the magenta component, C.I. I. Disperse thread 60, disperse violet 26, C.I. I. Solvent Red 27, or C.I. I. Solvent Red 19 may be mentioned. Further, as the cyan component, C.I. I. Disperse blue 354, 24, C.I. I. Solvent Blue 63, 36 etc. are mentioned.

  The binder resin carrying these dyes is not particularly limited, but cellulose resins such as ethylene cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, and cellulose acetate, polyvinyl alcohol, and polyvinyl acetate. And vinyl resins such as polyvinyl butyral, polyvinyl pyrrolidone, and polyacrylamide, polyester resins, styrene-acrylonitrile copolymer resins, and phenoxy resins. Of these, polyvinyl acetal, polyvinyl butyral, styrene-acrylonitrile copolymer resin, and phenoxy resin are preferably used.

  The ratio of the dye to the binder contained in the constituent material of the sublimation thermal ink layer is preferably from dye / binder = 10/100 (parts by weight) to 300/100 (parts by weight). When the ratio of the dye / binder is less than 10/100 (part by weight), the amount of dye is too small and the color development sensitivity becomes insufficient, and it becomes difficult to obtain a good thermal transfer image, and 300/100 (part by weight). If it exceeds 1, the solubility of the dye in the binder is extremely lowered, so that the storage stability of the thermal ink layer is deteriorated and the dye is likely to precipitate.

Examples of the constituent material of the release layer 7 include water-soluble polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, and sodium alginate, natural rubber derivatives such as chlorinated rubber and cyclized rubber, natural wax, Waxes such as synthetic waxes, fiber derivatives such as nitrocellulose, cellulose acetate, cellulose, cellulose acetate propionate, acrylic, polyurethane, polyamide, polyimide, polyacetal, chlorinated polyolefin, vinyl chloride-acetic acid Examples include vinyl copolymer systems, olefin-based thermoplastic resins, melamine-based, epoxy-based, polyurethane-based, silicone-based thermosetting resins, and the like.

  Among these, one type is selected, but two or more types of resins may be selected for adhesion control. One of them can be a resin similar to the main binder of the base sheet 1, and the constituent material of the release layer 7 can be adjusted to control the adhesion with the base sheet. As an example, when the base sheet is a polyester resin film, the base sheet is a polystyrene resin film prepared by mixing a polyester resin and another resin in a common solvent. In such a case, it may be provided in the form of a thin film using a mixture prepared by mixing a polystyrene resin and another resin in a common solvent.

  The addition amount of the resin similar to the main binder of the base sheet 1 is 0.2 to 60 parts by weight, preferably about 0.5 to 25 parts by weight when the main binder is 100 parts by weight. The compatibility, dissolution solvent, drying conditions, and compatibility with the resin used for the release layer 8 may be taken into consideration for selection. In this case, it is preferable that the two are compatible as much as possible, but this does not necessarily mean that they should be compatible, and they are mixed evenly with a common good solvent and evenly dispersed even if they are not completely compatible. If it is transparent, it does not matter. Moreover, thickness should just be 0.1-5 micrometers (dry film thickness), More preferably, it may be 0.3-2.0 micrometers (dry film thickness).

  The release layer 8 and the adhesive layer 9 that are transferred and become protective layers are layers for protecting the transfer image and the like by covering the transfer image recorded on the transfer medium and covering the transfer image. In some cases, a role of protecting from ultraviolet rays, ozone, or the like, or gloss as a design property is required. At the same time, since it is transferred onto the transfer medium by a process called a thermal transfer method, it is also necessary to have releasability that allows easy peeling from the substrate sheet side during heat transfer and adhesion to the image receiving layer side.

  The release layer 8 is positioned on the outermost layer when transferred onto the transfer medium, but it has transparency, friction resistance, contamination resistance, scratch resistance, mold release, hardness, heat resistance, and resistance. Various characteristics such as ozone and gloss are often required.

  Examples of the binder constituting the release layer 8 include styrene resins such as polystyrene and poly α-methylstyrene, acrylic resins including polymethyl methacrylate, polyethyl acrylate, and the like, copolymers with styrene, poly Vinyl resin such as vinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyvinyl acetal, polyester resin, polyamide resin, epoxy resin, polyurethane resin, petroleum resin, ionomer, ethylene-acrylic acid copolymer Synthetic resins such as copolymers, ethylene-acrylic acid ester copolymers, cellulose derivatives such as nitrocellulose, ethyl cellulose, cellulose acetate propionate, rosin, rosin-modified maleic resin, ester gum, polyisobutylene rubber, butyl rubber, Len - acrylonitrile rubbers, natural resins and derivatives of synthetic rubber polychlorinated olefins such as carnauba wax, waxes such as paraffin wax - butadiene rubber, butadiene. In addition, engineering plastics such as polycarbonate, super engineering plastics, and the like can also be used from the viewpoint of dissolving solvent, viscosity, hardness, and the like. Among these, acrylic resins and cellulose derivatives can be mentioned.

In some cases, a resin having an aromatic ring is preferably used. It has the steric hindrance due to the ring structure of the aromatic ring and entanglement of the aromatic ring, the hardness of the surface due to the denseness of the resin, the aromatic surface structure, etc. There is a possibility that can be given.

Examples of the resin having an aromatic ring include styrene resin, xylene resin, phenolic resin, ABS resin, phenoxy resin, ACS resin, AES resin, aniline resin, isocyanate resin, aromatic ring polyimide resin, oxetane resin, phthalic acid resin, Ester resin, terephthalic acid resin, novolak resin, benzoxazine resin, resol resin, acenaphthylene, naphthalene and other aromatic resins, AS resin, ABC resin, ASA resin, SAS resin, ACS resin, AMA resin, MS resin, MBS resin , Nylon resin, polyester resin, polyarylate resin, PEEK resin, PEKK resin, PSU resin, PES resin, benzophenone, PBI resin, quinazoline resin, carbonate resin, engineering plastics with aromatic rings, Sue It can be given over engineering plastics.
Of course, the resin may be a copolymer resin with the resin having the aromatic ring, or the resin itself or a mixture.

  If the resin constituting the adhesive layer 9 and the resin having an aromatic ring can be mixed or copolymerized, compatibility problems can be avoided, and further, the mixing amount can be freely changed, and the molecular weight can be increased. By doing so, the resin specific gravity in the layer and the free movement volume at the time of coating are closely controlled, and the release layer 8 and the adhesive layer 9 are made high molecular weight by using a curing agent as necessary. You can also However, in particular, the adhesive layer must have both heat resistance and transferability.

  The release layer 8 is not added with an ultraviolet absorber, and the ultraviolet absorbing ability is given to the adhesive layer 9 described later, thereby dividing the role of each layer with respect to color resistance and protecting the heat transferability transferred onto the transfer medium. By mixing the UV absorber in the adhesive layer 9 in the layer immediately above the image of the layer, it is possible to avoid fading and decomposition from the edge, and to effectively protect the print color by the UV absorption function. Further, it is preferable that the release layer located on the outermost surface does not contain a substance such as an ultraviolet absorber, so that safety can be further improved. However, the balance with the ultraviolet absorber content in the adhesive layer 9 is preferable. Therefore, the release layer 8 may be mixed with an ultraviolet absorber.

  In addition, since the release layer 8 is positioned on the outermost surface on the transfer medium after the image transfer, not only the ozone resistance but also the transparency, the friction resistance, the stain resistance, the scratch resistance, and the release property (transferability). , Hardness, design (gloss), adhesion, etc. are required, so silica, calcium carbonate, kaolin, talc, silicone powder, calcium sulfate, Barium sulfate, titanium dioxide, zinc oxide, satin white, zinc carbonate, magnesium carbonate, aluminum silicate, calcium silicate, magnesium silicate, silica, colloidal silica, colloidal alumina, pseudoboehmite, aluminum hydroxide, alumina, lithopone, zeolite, hydrohalo Site, inorganic filler such as magnesium hydroxide, acrylic plastic pigment, styrene Las tic pigments, microcapsules, urea resins, organic fillers such as melamine resin, polyethylene, carnauba wax, paraffin, silicone, a release agent may be added as appropriate, such as fluorine. These may be liquid or solid, and the shape is not particularly limited, and an appropriate one is selected from various shapes such as flakes and true spheres. That's fine. However, although easy peel transferability at the time of thermal transfer is particularly sought, if too many releasable additives are added to the release layer, due to bleeding over time, etc. Peeling may occur between the adhesive layer or the release layer, and adhesion with the peeling layer may be deteriorated even in a normal state. The thickness of the release layer 8 may be 0.1 to 5 μm (dry film thickness), more preferably 0.3 to 2.0 μm (dry film thickness).

The resin of the layer constituting the release layer 8 has a glass transition point (Tg) at room temperature or higher at the time of non-thermal transfer, but if the glass transition point (Tg) is exceeded at the time of thermal transfer, the thermal transferable protective layer is peeled and transferred. On the other hand, there may be a case where a transfer defect occurs due to fusion. Also, if a resin that has a high glass transition point (Tg) and improves releasability during thermal transfer is selected as the constituent material of the release layer, it may induce release from the adhesive layer during thermal transfer, or the coating film will become harder , May result in poor adhesion. The residual solvent amount of the layer not only causes the same effect as the release layer 7 but also transferred to the printed material, so that the printing failure, wrinkles, blocking, bleeding of the printed image, There is a high possibility of causing a color change.

  Next, the adhesive layer 9 will be described. The basic physical properties required for the adhesive layer 9 are to form a protective layer by transferring to the transfer medium side by thermal transfer, good film breakage during transfer, good thermal adhesion to the transfer medium, It has good transparency, does not impair the sharpness of the transferred image on the transferred image recording medium, and further retains the ability to absorb ultraviolet rays if necessary, and has ozone resistance.

  Examples of the constituent material of the adhesive layer 9 include acrylic resins, polystyrene, styrene resins such as poly-α-methylstyrene, acrylic resins such as polymethyl methacrylate and polyethyl acrylate, polyvinyl chloride, and polyvinyl acetate. , Vinyl chloride-vinyl acetate copolymer, polyvinyl resins such as polyvinyl butyral, polyvinyl acetal, phenoxy resin, phenol resin, polyester resin, polyamide resin, epoxy resin, polyurethane resin, petroleum resin, ionomer, ethylene-acrylic acid copolymer Polymers, synthetic resins such as ethylene-acrylic acid ester copolymers, cellulose derivatives such as nitrocellulose, ethyl cellulose, cellulose acetate propionate, rosin, rosin-modified maleic acid resin, ester gum, polyisobutylene rubber, butyl Beam, styrene - acrylonitrile rubbers, natural resins and derivatives of synthetic rubber polychlorinated olefins such as carnauba wax, waxes such as paraffin wax - butadiene rubber, butadiene. Among these, acrylic resins, polyesters, epoxies, phenoxy resins, and the like can be given. Of course, as long as heat transfer adhesiveness can be provided, the resin is not limited to a thermoplastic resin, and a thermosetting resin or a mixture of a curing agent with the thermoplastic resin may be used. Furthermore, it is also possible to use a photocurable resin.

  As a functional additive to be mixed in the constituent material of the adhesive layer 9 or the release layer 8, in addition to the above-described ultraviolet absorbers and light stabilizers typified by hindered amines, thermal oxidation prevention typified by hindered phenols is used. An agent, a fluorescent brightening agent, an antistatic agent, a flame retardant, etc. can also be mentioned.

  Specific examples of ultraviolet absorbers added to and mixed in the adhesive layer 9 include those of benzotriazole, benzophenone, triazine, and salicylate, and those including JP-A-59-196292 and JP-A-59. -158287, JP-A 63-74686, JP-A 59-196292, JP-A 62-229495, JP-A 63-122596, JP-A 61-283595, Examples thereof include compounds described in JP-A-1-204788 and the like, and known compounds that improve image durability in photographs and other image recording materials.

  Examples of the benzotriazole-based ultraviolet absorber include 2- (2H-benzotriazol-2-yl) -p-cresol, 2- (2H-benzotriazol-2-yl) -4-6-bis (1- Methyl-1-phenylethyl) phenol, 2- [5-chloro (2H) -benzotriazol-2-yl] -4-methyl-6- (tert-butyl) phenol, 2- (2H-benzotriazol-yl) -4,6-di-tert-pentylphenol, 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol and the like, mixtures thereof, modified products, Polymers and derivatives can be exemplified, and these can be used alone or in combination.

  Examples of triazine ultraviolet absorbers include 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol, 2- [4-[( 2-hydroxy-3-dodecyloxypropyl) oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine, 2- [4-[(2- Hydroxy-3-tridecyloxypropyl) oxy] -2-hydroxyphenyl] -4,6-bis (2,4dimethylphenyl) -1,3,5-triazine, 2,4-bis (2,4-dimethyl) Phenyl) -6- (2-hydroxy-4-iso-octyloxyphenyl) -s-triazine and the like, and mixtures, modified products, polymers, and derivatives thereof.

  The amount of the UV absorber is 3 to 200 parts by weight, preferably about 5 to 100 parts by weight with respect to 100 parts by weight of the resin, although it depends on the UV absorbing ability of the UV absorber and the compatibility with the resin. It is preferable to add. When the addition amount is less than 3 parts by weight, there is a case where sufficient ultraviolet absorbing ability cannot be exhibited in the thermal transfer protective layer. Moreover, when it exceeds 200 parts by weight, the cohesive force in the layer is also affected, and the toughness of the resin layer may be reduced, transparency may be lost, or blocking may occur. Further, depending on the type of the ultraviolet absorber, it may contribute to imparting ozone resistance, and the addition amount may be appropriately determined from the viewpoint of protecting the adhesive layer itself and protecting the image. When it is desired to remove the presence of the additive on the outermost surface, a method of adding to the adhesive layer 9 is taken, and when the physical properties cannot be satisfied with the adhesive layer 9 alone due to a content problem or the like, Including the meaning of protecting the color of the lower layer while protecting itself, it is also possible to mix the release layer 8 and the adhesive layer 9 uniformly or in an inclined manner.

  In addition to these ultraviolet absorbers, hindered amine light stabilizers can also be added. Examples of hindered amine light stabilizers include dimethyl succinate 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine, poly [{6- (1,1,3, 3-tetramethylbutyl) amino-1,3,5-triazine-2,4diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6 6-tetramethyl-4-piperidyl) imino}], N, N′-bis (3-aminopropyl) ethylenediamine · 2,4-bis [N-butyl-N- (1,2,2,6,6- Pentamethyl-4piperidyl) amino] -6-chloro-1,3,5-triazine, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2- (3,5-di-t- Butyl-4-hydroxybenze ) -2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl), tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) 1,2, Examples include 3,4-butanetetracarboxylate.

  The adhesive layer 9 may be provided in the form of a thin film by preparing a coating liquid by blending the functional additive, binder, solvent and the like as described above. The thickness of the adhesive layer is suitably 0.2-5 μm (dry film thickness).

  Next, the case where the protective layer of FIG. 1 is a single layer will be described as an example. The above-mentioned protective layer can be used by mixing two layers of resin. For example, the polyvinyl alcohol resin used in the release layer 7 is mixed with a polyester resin as an adhesion aid to the base material as necessary, and further mixed with an acrylic resin as an adhesive layer component necessary for printing, By controlling the glass transition point (Tg) and the like, transparency and transferability can be obtained.

Also, as another example, acrylic resin is the main, in order to improve the release transferability there,
Silicone additives, fluorine additives, waxes, and the like can also be added. Further, a resin obtained by modifying the terminal of the acrylic resin with silicone can be used as it is. In any case, it is necessary to have both a close contact with the base material at the normal state and a transfer property at the time of overheating.

  Further, even when the protective layer is a single layer, the above-described ultraviolet absorber can be used and may be mixed conveniently. The thickness of the protective layer may be 0.2 μm to 5 μm (dry film thickness).

  In order to create the thermal transfer sheet of the present invention, each of the thermal ink layers, sensor layers, release layers, release layers and adhesive layers can be formed by any known coating method such as gravure coating or slot coating. A thin film forming method can be used. Each layer can be formed by applying a thin film with a coating liquid for forming each layer and drying it.

  It is necessary to have a technology that separates layers with cost and each function, and from the setting of the coating method and coating conditions, unless the coating speed is increased as much as possible, the coated surface often does not become good, From the viewpoint of cost performance, it is preferable to further increase the coating speed. However, the drying is insufficient and the solvent remains in the coating film. If the drying temperature is raised to reduce the residual solvent, problems such as color change during printing with the thermal ink layer, transfer failure due to additive bleeding, influence on wrinkles, and expansion / contraction of the base material also occur. There is also a case where it ends up.

  The adhesive layer 9 in the case where the protective layer is two layers may be a little thicker than other release layers 7 and release layers 8 depending on the required physical properties, and when it is printed and wound, it comes to the outermost layer. Therefore, if there is a large amount of residual solvent in the layer, blocking with the heat-resistant slipping layer 2 that comes into contact with the winding or the solvent component that has moved to the heat-resistant slipping layer 2 diffuses, and the heat-sensitive ink layer is transferred to the heat-resistant slipping layer 2. In many cases, the dye that has been transferred to the adhesive layer 9 (so-called reverse transfer). Furthermore, it may cause jamming, wrinkles, transfer failure, etc. during printing. Also, in the printed matter after printing, if the residual solvent remains even with heat at the time of printing, it affects the bleeding of the printed dye and the stability over time (storability), and the color change at the time of printing after storage It will change.

  As a result of intensive studies, we have been able to avoid the above problems by defining the amount of residual solvent in the coating film after drying of the protective layer, that is, the range of residual solvent in the coating film mass. Even if the amount of residual solvent exceeds the upper limit, the above-mentioned problems such as jamming occur, and if the drying is strengthened to make it less than the lower limit value, the above-mentioned problems such as color change at the time of printing, substrate expansion / contraction (dimension change), etc. occur. is there. Therefore, the residual solvent ratio (weight) in the coating film mass is 0.001 wt% to 9.000 wt%. Preferably, the residual solvent amount ratio in the coating film mass is 0.002 wt% to 5.000 wt%.

  Next, the thermal transfer member includes a support and an image receiving layer. The support can be the same as that used as the base material of the thermal transfer recording medium, and preferably has mechanical strength, flexibility, heat resistance and the like. Specifically, polyesters such as polyethylene terephthalate and polyethylene naphthalate, plastic films such as polyethylene, polyvinyl chloride, polycarbonate, polyester, polysulfane, polyimide, polyvinyl alcohol, aromatic polyamide, and aramid film, fine paper, Examples thereof include paper base materials such as coated paper and synthetic paper. The thickness of the support is not particularly limited, but is generally 25 to 250 μm, more preferably 75 to 200 μm.

  As the image receiving layer, when a sublimation dye is used for the thermal transfer layer, for example, butyral resin having a dyeing property, polyethylene, polyurethane, polypropylene, polyvinyl chloride, polybutadiene, polyvinyl acetate, vinyl chloride-vinyl acetate. Uses thermoplastic resins such as copolymers, ethylene-vinyl acetate copolymers, polyamides, polyesters, polycaprolactones, polyvinyl acetals, epoxies, ketones, modified resins and blends thereof, and cross-linked products thereof. can do. These may be used alone or in combination of two or more. If the film thickness of the image receiving layer is too thin, the reflection density of the image is lowered and it becomes difficult to form a sufficient image. On the other hand, if the thickness is too large, image quality such as color bleeding is deteriorated. Therefore, it is generally 1 to 30 μm, preferably 3 to 10 μm. In this case, the image receiving layer preferably contains various release agents for the purpose of preventing thermal fusion to the thermal transfer recording body during image formation. As such a release agent, a known release agent can be appropriately selected and used. For example, various oils such as silicone-based, fluorine-based, and phosphate-based oils, various fillers such as surfactants, metal oxides, and silica can be used, and among these, silicone oil is preferably used. The amount added varies depending on the constituent conditions of the image-receiving layer, but generally it is preferably 1 to 30% by weight.

  As the substrate sheet 1, a polyethylene terephthalate film (diafoil: manufactured by Mitsubishi Chemical Polyester Film) with a thickness of 5 μm and an easy adhesion treatment was used. On the back side, 100 parts by weight of polyester polyol resin (Acricic: manufactured by DIC), 10 parts by weight of isocyanate curing agent (Takenate: manufactured by Mitsui Chemicals Polyurethane), and 1 part by weight of lubricant (phosphate ester: No. 1) Manufactured by Ichi Kogyo Seiyaku Co., Ltd.), 36 parts by weight of methyl ethyl ketone and 36 parts by weight of toluene were dissolved in a mixed solvent to prepare a coating agent. The prepared coating agent was formed on the non-adhesive side of the base sheet so as to have a dry film thickness of 1.0 μm by gravure coating, and subjected to reaction curing to obtain a heat resistant slipping layer 2.

  The thermal ink layer 3 (yellow) is C.I. I. 3.0 parts by weight of Solvent Yellow 93, C.I. I. Solvent yellow 16 is dissolved in a mixed solvent consisting of 1.0 part by weight, polyvinyl acetal resin is 5.0 parts by weight (Denka Butyral: manufactured by Denki Kagaku Kogyo), methyl ethyl ketone is 45 parts by weight, and toluene is 45 parts by weight. Was made.

  The thermal ink layer 4 (magenta) is C.I. I. 1.5 parts by weight of disperse thread 60, C.I. I. Disperse violet 26 is dissolved in a mixed solvent consisting of 1.5 parts by weight, polyvinyl acetal resin 5.0 parts by weight (Denkabutyral: manufactured by Denki Kagaku Kogyo), 46 parts by weight of methyl ethyl ketone, and 46 parts by weight of toluene. A liquid was prepared.

  The thermal ink layer 5 (cyan) is C.I. I. 1.5 parts by weight of Solvent Blue 63, C.I. I. Solvent Blue 36, 1.5 parts by weight of polyvinyl acetal resin (5.0 parts by weight of Denkabutyral: manufactured by Denki Kagaku Kogyo), 46 parts by weight of methyl ethyl ketone, and 46 parts by weight of toluene are dissolved in a mixed solvent. Was made.

  As the release layer 7, 6 parts by weight of a cellulose acetate resin (manufactured by Daicel Chemical Industries) and 2 parts by weight of a polyester resin are dissolved in a mixed solution of 87 parts by weight of methyl ethyl ketone and 5 parts by weight of cyclohexanone to obtain a coating solution for the release layer. Was made.

  The release layer 8 was prepared by dissolving 100 parts by weight of an acrylic resin (Dianar: manufactured by Mitsubishi Rayon), 100 parts by weight of methyl ethyl ketone, and 50 parts by weight of toluene to prepare a coating solution for the release layer. .

  The adhesive layer 9 comprises 100 parts by weight of an acrylic resin, 20 parts by weight of a benzotriazole UV absorber, 1 part by weight of a hindered amine light stabilizer, 1 part by weight of a thermal antioxidant, 50 parts by weight of methyl ethyl ketone, and 50 parts by weight of toluene. An adhesive layer coating solution was prepared by dissolving in a mixed solvent consisting of

For the sensor layer 10, a coating solution was prepared from 15 parts by weight of a polyester resin, 15 parts by weight of carbon black, 10 parts by weight of toluene, 40 parts by weight of methyl ethyl ketone, and 20 parts by weight of ethyl acetate and an auxiliary agent.

The sensor layer, the thermal ink layer (yellow), the thermal ink layer (magenta), and the thermal ink layer (cyan) are dried on the easy-adhesion side surface of the base sheet using the gravure coating method. Formed in a film sequence with a film thickness of 1.0 μm. Further, after forming a release layer with a film thickness of 0.2 μm in a film order, a release layer was formed on the mold release layer with a film thickness of 0.3 μm. Further, an adhesive layer was formed on the release layer with a dry film thickness of 2.0 μm to produce the thermal transfer sheet of the present invention.
At that time, the printing speed was 100 m / min, the thermal ink layer drying units were all 80 ° C., and the mold release, release and adhesion drying units were 90 ° C.

  All layers were applied in the same manner as in Example 1 above. However, the drying temperatures of the three heat-sensitive ink layers, the sensor layer, the release layer, and the release layer were the same, and only the adhesive layer was dried at a temperature of 100 ° C. to prepare a thermal transfer sheet.

<Comparative Example 1>
The adhesive layer was coated as in Example 1 above, the drying temperature of the three thermal ink layers was the same as in Example 1, the drying temperature of the release layer, release layer, and adhesive layer was 70 ° C., and the thermal transfer sheet was Produced.

<Comparative example 2>
The coating is applied to the adhesive layer under the same conditions as in Comparative Example 1, but the drying temperature of the three color layers is the same as in Example 1. The release layer and release layer are dried at 70 ° C., and only the adhesive layer is dried at 60 ° C. The thermal transfer sheet was prepared at a temperature of 0 ° C.

In addition, about the to-be-transferred body, the dry film thickness of 5 micrometers was formed using the gravure coat method and the image receiving layer forming ink for sublimation heat transfer of the following prescription on one side of the to-be-transferred base material.
(Image-receiving layer forming ink formulation for sublimation thermal transfer)
-Transfer target substrate: white polyester film 75 μm
-Resin: 20 parts by weight of vinyl chloride-vinyl acetate-vinyl alcohol copolymer-Resin: 2 parts by weight of polyisocyanate
-Mold release agent: 0.5 parts by weight of silicone oil-Solvent: 40 parts by weight of toluene, 40 parts by weight of methyl ethyl ketone

  The contents of performance evaluation and judgment criteria are shown.

(1) Residual solvent The laminated portion of the protective layer and the release layer on the thermal transfer sheets prepared in Examples 1 and 2 and Comparative Examples 1 and 2 was cut into 10 cm square, sealed in vials, and gas chromatographed. (Manufactured by Shimadzu Corporation), the remaining amount of each solvent was measured, converted from the dry coating amount, and the residual solvent X% was calculated. <Evaluation judgment>
○: 0.001% ≦ X% ≦ 9.0000%
X: Range other than X% above

(2) Print transferability (jamming confirmation)
For the thermal transfer sheets prepared in Examples 1 and 2 and Comparative Examples 1 and 2, the sublimation printer was operated in an environment of 25 ° C. and 50%, and three black solids were printed with the printer full power, and the transfer protective layer was transferred. An abnormality was confirmed.
<Evaluation judgment>
○: The entire surface transfer protective layer was transferred without any problem.
X: The transfer protective layer was transferred partially or entirely.

(3) About the thermal transfer sheet produced in Blocking Examples 1 and 2 and Comparative Examples 1 and 2, it was unwound and a part of the transfer-related layer was visually checked for blocking.
<Evaluation judgment>
○: No blocking without peeling between layers.
X: Some or all of the layers were blocked.

(4) Back / Inside Back For the thermal transfer sheets prepared in Examples 1 and 2 and Comparative Examples 1 and 2, the part where the yellow was transferred to the adhesive layer by a half of the slit was transferred under an environment of 25 ° C. and 50%. Using a sublimation printer, a solid white image was printed, a yellow printed portion and a non-printed portion were measured with a reflection densitometer, and the difference in reflection density (Δab) was calculated.
<Evaluation judgment>
○: Δab value: less than 0.5 ×: Δab value: 0.5 or more

(5) Storage fading property The thermal transfer sheets prepared in Examples 1 and 2 and Comparative Examples 1 and 2 were stored at 50 ° C. for 7 days, and then a five-step portion of 11 steps using a sublimation printer at 25 ° C. and 50%. The reflection density was measured, and the difference (ΔOD) before and after storage was calculated.
(Colorimeter: X-Rite: manufactured by Nidec)
<Evaluation judgment>
○: ΔOD value: less than ± 0.03 ×: ΔOD value: ± 0.03 or more

評価結果を示す。

An evaluation result is shown.

残留溶剤（Ｘ％）の測定結果を示す。

The measurement result of residual solvent (X%) is shown.

  The present invention relates to a thermal transfer sheet having a layer for protecting an image formed by various image recording apparatuses, that is, a printed material, particularly a printed material using a dye, and is inexpensive and stable. It has become possible to provide a thermal transfer sheet having a typical printability.

DESCRIPTION OF SYMBOLS 1 ... Base material sheet 2 ... Heat-resistant slipping layer 3 ... Thermal ink layer (yellow)
4 ... Thermal ink layer (magenta)
5 ... Thermal ink layer (cyan)
6 ... protective layer 7 ... release layer 8 ... release layer 9 ... adhesive layer
10 ... Sensor layer

Claims (2)

  A yellow dye layer, a magenta dye layer, a cyan dye layer, a protective layer, and a sensor layer as at least a sublimation thermal ink layer are repeatedly provided on one side of the base material in the longitudinal direction. In the thermal transfer sheet, the protective layer comprises one or more layers, and the residual solvent mass in the protective layer is 0.001 wt% or more and 9.000 wt% or less with respect to the mass of the protective layer. Characteristic thermal transfer sheet.   A printed matter produced using the thermal transfer sheet according to claim 1.

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