JP2006263987A - Thermal transfer recording material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal transfer recording material being a combination of a thermal transfer sheet and a thermal transfer image accepting sheet, which enables attainment of a satisfactory printing density corresponding to an increase of a printing speed of thermal transfer and eliminates fusion between a dye layer of the thermal transfer sheet and an accepting layer of the thermal transfer image accepting sheet, of which the thermal transfer sheet has excellent shelf stability and which makes excellent the durability of light-resistance and the like of a print obtained by transferring dye from the dye layer to the accepting layer by using the thermal transfer sheet and the thermal transfer image receiving sheet. <P>SOLUTION: The thermal transfer recording material 1 is composed of the thermal transfer sheet 2 having the dye layer 4 provided at least on one side of a base sheet 3 and of the thermal transfer image accepting sheet having the accepting layer provided on at least one side of a base 12. The dye layer and the accepting layer 13 are laid on each other and the dye in the dye layer can be transferred onto the accepting layer by a heating means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thermal transfer recording material that is a combination of a thermal transfer sheet provided with a dye layer on a base sheet and a thermal transfer image receiving sheet provided with a receiving layer on the base sheet. Sufficient print density is obtained, the dye layer of the thermal transfer sheet and the receiving layer of the thermal transfer image receiving sheet are not fused, and the thermal transfer sheet has good storage stability, and the dye is transferred from the dye layer to the receiving layer. The printed matter obtained in this way relates to a thermal transfer recording material having good durability such as light resistance.

  Conventionally, various thermal transfer methods are known. Among them, a sublimation dye is used as a recording material, and this is supported on a substrate sheet such as paper or plastic film to form a thermal transfer sheet, which can be dyed with a sublimation dye. There have been proposed methods for forming various full-color images on a thermal transfer image-receiving sheet, for example, a thermal transfer image-receiving sheet provided with a dye-receiving layer on the surface of paper or plastic film. Since this method uses a sublimation dye as a color material, the density gradation can be freely adjusted, and a full color image of an original can be expressed. In addition, the image formed with the dye is very clear and excellent in transparency, so it is excellent in intermediate color reproducibility and gradation reproducibility, and can form high-quality images comparable to silver salt photographs. Is possible.

  In recent years, as the printing speed of thermal transfer printers has been increased, there has been a problem that sufficient print density cannot be obtained with conventional thermal transfer recording materials. In contrast, for example, the dye / resin (Dye / Binder) ratio in the dye layer of the thermal transfer sheet was increased, but the dye migrated to the heat-resistant slipping layer on the back side of the thermal transfer sheet during winding and storage. When the transferred dye rolls back, it re-transfers to a dye layer of another color or a transferable protective layer (kickback), and when this contaminated layer is thermally transferred to the image receiving sheet, a hue different from the specified color is obtained. Or so-called soiling occurs. In addition, high energy is applied during thermal transfer during image formation, but the dye layer and the receiving layer are fused, so-called abnormal transfer occurs. If a large amount of a release agent is added to the receiving layer to prevent the abnormal transfer, the printing sensitivity is lowered and the printing density is lowered.

  In Patent Document 1, a polyvinyl acetal resin having an aralkyl group or an aryl group-containing vinyl group is used as a main component of a receiving layer of a thermal transfer image-receiving sheet, whereby high density recording in printing can be performed, and light fastness and fixing properties can be obtained. It is shown that a recorded matter having good storage stability can be obtained. Patent Document 2 includes an image-receiving layer obtained by thermally curing a composition containing a resin containing active hydrogen, a silicone resin, a modified silicone oil having a functional group that reacts with an isocyanate group, and a polyfunctional isocyanate compound. A thermal transfer image-receiving sheet is described, and a polyvinyl acetal resin is used as the resin having active hydrogen, and it is shown that high-density recording can be performed and the dye layer and the image-receiving layer are not fused.

However, as the printing speed of thermal transfer printers continues to increase, the heat applied to the thermal head, and therefore the heat applied to the receiving layer of the image receiving sheet, has increased, and the dye layer and the receiving layer are likely to be fused. Under the present circumstances, a conventional thermal transfer image-receiving sheet cannot be used without any problem.
Japanese Patent Laid-Open No. 03-162989 Japanese Patent Laid-Open No. 03-227690

  Therefore, the present invention provides a sufficient printing density corresponding to the increase in the printing speed of thermal transfer, the dye layer of the thermal transfer sheet and the receiving layer of the thermal transfer image receiving sheet are not fused, and the thermal transfer sheet Thermal transfer sheet and thermal transfer image-receiving sheet having good durability such as light resistance of the printed matter obtained by transferring the dye from the dye layer to the receiving layer using the thermal transfer sheet and the thermal transfer image-receiving sheet. It is an object of the present invention to provide a thermal transfer recording material that is a combination of the above.

上記の式中Ｒは、置換基を有してもよいアリール基、アラルキル基、あるいはアリール基含有ビニル基を表し、ｌ、ｍ、ｎは各構造単位のモル％を表し、５０＜ｌ＜８５、１０＜ｍ＜５０、０＜ｎ＜３０の範囲である。 The present invention comprises, as claim 1, a thermal transfer sheet having a dye layer on at least one surface of a substrate sheet, and a thermal transfer image receiving sheet having a receptor layer on at least one surface of the substrate. In the thermal transfer recording material in which the receptor layer of the thermal transfer image-receiving sheet contains an acetal resin, and the dye of the thermal transfer sheet, The layer contains a polyester resin having a bisphenol skeleton. In claim 2, the acetal resin of the receiving layer according to claim 1 is represented by the following general formula, the degree of polymerization of the acetal resin is 1000 or more, and mol% of the acetal part: Is 50% or more based on the whole resin, and 80 mol% or more of the acetal portion is polyvinyl acetoacetal or polyvinyl butyl acetal.

In the above formula, R represents an aryl group, an aralkyl group, or an aryl group-containing vinyl group which may have a substituent, and l, m, and n represent mol% of each structural unit, and 50 <l <85. 10 <m <50 and 0 <n <30.

  As a third aspect, the dye layer according to the first aspect includes a polyester resin using a polyol having a bisphenol skeleton as an alcohol component. As a fourth aspect, the receiving layer according to the first or second aspect further includes a release agent. In addition, as a fifth aspect, the dye layer according to the first or third aspect further includes a release agent.

  The thermal transfer recording material of the present invention comprises a thermal transfer sheet having a dye layer on at least one surface of a substrate sheet, and a thermal transfer image receiving sheet having a receiving layer on at least one surface of the substrate. A thermal transfer recording material in which a dye layer in the dye layer can be transferred to the receptor layer by heating means, the receptor layer of the thermal transfer image receptor sheet contains an acetal resin, and the thermal transfer sheet The dye layer contains a polyester resin having a bisphenol skeleton. Thus, by defining the conditions of the resin that constitutes the receiving layer of the thermal transfer image-receiving sheet and the conditions of the resin that constitutes the dye layer of the thermal transfer sheet, that is, by specifying the conditions for the combination of the receiving layer and the dye layer, Corresponding to higher printing speed of thermal transfer, sufficient printing density is obtained, the dye layer of the thermal transfer sheet and the receiving layer of the thermal transfer image receiving sheet are not fused during thermal transfer, and the storage stability of the thermal transfer sheet is good. The printed matter has good durability such as light resistance.

  One embodiment of the thermal transfer recording material of the present invention is shown in FIG. The illustrated thermal transfer recording material 1 is composed of a combination of a thermal transfer sheet 2 and a thermal transfer image receiving sheet 11. The thermal transfer sheet 2 is provided with a dye layer 4 on one side of a base sheet 3, and the other side of the base sheet 3. Is provided with a heat resistant slipping layer 5. The thermal transfer image receiving sheet 11 has a configuration in which a receiving layer 13 is provided on one surface of a substrate 12 and a back layer 14 is provided on the other surface of the substrate 12. The thermal transfer sheet of the present invention is not limited to the one shown in the figure. The thermal transfer sheet of the present invention is provided with an easy-adhesion layer or the like between the base sheet and the dye layer, or a layer such as an antistatic layer on the heat-resistant slip layer. May be formed. Further, the thermal transfer image-receiving sheet of the present invention has an antistatic layer, a cushion layer, an intermediate layer added with a white pigment and a fluorescent whitening agent or an easily adhesive layer between the base material and the receiving layer as necessary. It may be formed. Further, a layer such as an antistatic layer may be formed on the back layer.

Hereinafter, the thermal transfer sheet of the thermal transfer recording material of the present invention and each layer constituting the thermal transfer image receiving sheet will be described.
(Substrate sheet)
The substrate sheet 3 of the thermal transfer sheet used in the present invention may be any material as long as it has a conventionally known degree of heat resistance and strength, for example, 0.5 to 50 μm, preferably about 1 to 10 μm. Polyethylene terephthalate film of thickness, 1,4-polycyclohexylenedimethylene terephthalate film, polyethylene naphthalate film, polyphenylene sulfide film, polystyrene film, polypropylene film, polysulfone film, aramid film, polycarbonate film, polyvinyl alcohol film, cellophane, Examples thereof include cellulose derivatives such as cellulose acetate, polyethylene films, polyvinyl chloride films, nylon films, polyimide films, ionomer films, and the like.

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

  Furthermore, it is also possible to apply and form an easy-adhesion layer between the base material and the dye layer as the adhesive treatment of the base material sheet. The easy adhesion layer can be formed from the following resin. Polyester resin, Polyacrylate resin, Polyvinyl acetate resin, Polyurethane resin, Styrene acrylate resin, Polyacrylamide resin, Polyamide resin, Polyether resin, Polystyrene resin, Polyethylene resin, Polypropylene Examples thereof include resins, polyvinyl chloride resins, polyvinyl alcohol resins, vinyl resins such as polyvinyl pyrrolidone, and polyvinyl acetal resins such as polyvinyl acetoacetal and polyvinyl butyral.

(Dye layer)
The thermal transfer sheet used in the present invention is one in which the dye layer 4 is provided on at least one surface of the above-described base material sheet. The dye layer may be composed of a single layer of one color, or a plurality of dye layers containing dyes having different hues may be repeatedly formed on the same surface of the same substrate sheet in the surface order. The dye layer is a layer formed by supporting a heat transferable dye with a binder. As the dye to be used, a dye that melts, diffuses or sublimates by heat, and is used in a conventionally known sublimation transfer type thermal transfer sheet can be used in the present invention. The selection is made in consideration of printing sensitivity, light resistance, storage stability, solubility in a binder, and the like.

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

  In the present invention, the dye layer of the thermal transfer sheet is characterized in that a polyester resin having a bisphenol skeleton is used as a binder. This modified polyester resin is synthesized using the following modified polyol component as an alcohol component. The modified polyol component has a bisphenol skeleton, and examples thereof include bisphenol A, bisphenol B, bisphenol AF, and bisphenol S. As a polyol component, you may use together ethylene glycol, neopentyl glycol, etc. which do not have a bisphenol skeleton, and what has a bisphenol skeleton. In synthesizing the modified polyester resin, each component does not have to be a single component, and a plurality of components may be appropriately combined.

  The production method of the modified polyester resin itself may be a known method, and may be a known method such as dehydration condensation or transesterification condensation. The molecular weight of these modified polyester resins is preferably in the range of 2000 to 60000 in terms of number average molecular weight, more preferably 10,000 to 55000 from the viewpoint of solubility. Moreover, in Tg, it is preferable that it is 60-100 degreeC. The dye layer may be used by mixing not only a single type of the above-mentioned modified polyester resin but also a plurality of types of modified polyester resins. In addition, a modified polyester resin is mainly used as a binder resin for the dye layer, and a cellulose resin, an acetal resin, a butyral resin, a phenoxy resin, or the like can be additionally used.

  In addition to the above dye and binder resin, a release agent can be added to the dye layer. By adding this release agent, it is possible to further prevent fusion with the receiving layer during thermal transfer. Examples of the release agent include silicone surfactants and fluorine surfactants. The silicone-based surfactant is a compound in which a hydrophobic part is made of a silicone resin, and a hydrophilic group is introduced into the terminal and / or side chain thereof. Typical examples of the silicone resin include poly (dimethyl) siloxane, methylphenyldimethylpolysiloxane, tetramethyltetraphenylpolysiloxane, dimethylpolysiloxane / polymethylphenylsiloxane copolymer, polymethylsiloxane, tetramethylpolymethylsiloxane, Examples thereof include polymethylsiloxane / polydimethylsiloxane copolymer in which a part or all of the side chain methyl groups are substituted with phenyl groups or hydrogen atoms. Examples of the hydrophilic group introduced into the silicone resin include a polyether group, a polyglycerin group, a pyrrolidone group, a betaine group, a sulfate group, a hydroxyl group, a carboxyl group, a phosphate group, and a quaternary ammonium base.

  These silicone resins and hydrophilic groups can be used in appropriate combination. In addition, regarding the structure of the surfactant, not only a hydrophilic group is simply introduced into the terminal and / or side chain of the above-mentioned silicone resin, but also a polymer in which a hydrophilic group is introduced and a polymer in which a hydrophilic group is not introduced are randomly copolymerized and blocked. It may be copolymerized by copolymerization. Among these, a silicone surfactant into which polydimethylsiloxane is introduced as a silicone resin and a polyether group, polyglycerin group, or pyrrolidone group is introduced as a hydrophilic group is preferably used.

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

(Heat resistant slipping layer)
In the thermal transfer sheet of the present invention, a heat-resistant slipping layer 5 can be provided on one surface of the substrate sheet in order to prevent adverse effects such as sticking and printing wrinkles due to the heat of the thermal head. The resin for forming the heat-resistant slipping layer may be any conventionally known resin such as polyvinyl butyral resin, polyvinyl acetoacetal resin, polyester resin, vinyl chloride-vinyl acetate copolymer, polyether resin, polybutadiene. Resin, styrene-butadiene copolymer, acrylic polyol, polyurethane acrylate, polyester acrylate, polyether acrylate, epoxy acrylate, urethane or epoxy prepolymer, nitrocellulose resin, cellulose nitrate resin, cellulose acetate propionate resin, cellulose acetate Butyrate resin, cellulose acetate hydrodiene phthalate resin, cellulose acetate resin, aromatic polyamide resin, polyimide resin, polyamideimide resin, poly Boneto resins, and chlorinated polyolefin resins.

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

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

Below, each layer of the component in the thermal transfer image receiving sheet used by this invention is demonstrated.
(Base material)
It is desirable that the base material 12 of the thermal transfer image receiving sheet has a role of holding the receiving layer and has mechanical characteristics that can withstand heat applied during image formation and that does not hinder handling. The material of such a substrate is not particularly limited. For example, polyester, polyarylate, polycarbonate, polyurethane, polyimide, polyetherimide, cellulose derivative, polyethylene, ethylene / vinyl acetate copolymer, polypropylene, polystyrene, acrylic, poly Vinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl butyral, nylon, polyether ether ketone, polysulfone, polyether sulfone, tetrafluoroethylene / perfluoroalkyl vinyl ether, polyvinyl fluoride, tetrafluoroethylene / ethylene, tetrafluoroethylene / Various plastic films or sheets such as hexafluoropropylene, polychlorotrifluoroethylene, and polyvinylidene fluoride Can be used is not particularly limited.

  White films formed by adding white pigments and fillers to the above plastic films or sheets, or sheets having microvoids inside the substrate, as well as condenser paper, glassine paper, sulfuric acid paper, synthetic paper ( Polyolefin, polystyrene), fine paper, art paper, coated paper, cast coated paper, synthetic resin or emulsion impregnated paper, synthetic rubber latex impregnated paper, synthetic resin internal paper, cellulose fiber paper, and the like. Moreover, the laminated body by arbitrary combinations of said base material can also be used. Typical examples include a laminate of cellulose fiber paper and synthetic paper, and cellulose fiber paper and a plastic film.

  Moreover, the base material which carried out the easy adhesion process on the surface and / or the back surface of said base material can also be used. The thickness of these base materials is usually about 3 to 300 μm, and it is preferable to use a base material of 100 to 250 μm in consideration of mechanical suitability and the like. Moreover, when the adhesiveness of a base material and the layer provided on it is scarce, it is preferable to perform an easily bonding process or a corona discharge process on the surface.

上記の式中Ｒは、置換基を有してもよいアリール基、アラルキル基、あるいはアリール基含有ビニル基を表し、ｌ、ｍ、ｎは各構造単位のモル％を表し、５０＜ｌ＜８５、１０＜ｍ＜５０、０＜ｎ＜３０の範囲である。 (Receptive layer)
One receiving layer 3 of the thermal transfer image-receiving sheet in the present invention is formed by containing at least one kind of thermoplastic resin on at least one surface of the substrate, and receives and forms a sublimation dye transferred from the thermal transfer sheet. This is for maintaining the thermal transfer image. In the present invention, the receiving layer of the thermal transfer image receiving sheet is characterized by using an acetal resin as a binder. The acetal resin is obtained by acetalizing polyvinyl alcohol, and those represented by the following general formula are preferably used.

In the above formula, R represents an aryl group, an aralkyl group, or an aryl group-containing vinyl group which may have a substituent, and l, m, and n represent mol% of each structural unit, and 50 <l <85. 10 <m <50 and 0 <n <30.

  The degree of acetalization of the acetal resin is 50% or more, and the mol% of the acetal part is preferably 50% or more and 85% or less with respect to the whole resin. Further, it is desirable that 80 mol% or more of the acetal portion is polyvinyl acetoacetal or polyvinyl butyl acetal. When polyvinyl alcohol (PVA) is acetalized, it is difficult to completely acetalize PVA, and acetyl groups and hydroxyl groups partially remain irreversibly. In the case of a polyvinyl acetoacetal resin, when the mol% of the acetal part is less than 50% relative to the total amount of the polymer, or when the amount exceeding 20 mol% of the acetal part is other than polyvinylacetoacetal, In some cases, the solubility in a solvent that dissolves dyes such as toluene and methyl ethyl ketone is poor, and the processability (coating suitability) may not be excellent.

  In this case, other aldehydes may be used for the purpose of improving the solvent solubility of the binder resin and improving the affinity (adhesion) with the substrate. As the aldehyde used in the acetalization reaction when obtaining the resin, formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, hexylaldehyde, 2-ethylhexylaldehyde, benzaldehyde, 1-naphthaldehyde, o-tolualdehyde, p-tolualdehyde , P-ethylbenzaldehyde, o-chlorobenzaldehyde, m-chlorobenzaldehyde, p-chlorobenzaldehyde, 3-phenylchloropionaldehyde and the like. However, it is not limited to these.

  The degree of polymerization of the acetal resin used in the receiving layer may be 1000 or more, and preferably 1000 to 2500. This is because if the degree of polymerization is too high, the viscosity of the solution is high and it is difficult to handle industrially. On the other hand, if the degree of polymerization is less than 1000, heat fusion with the dye layer (releasability at the time of printing tends to deteriorate) tends to be unfavorable. The molecular weight of the acetal resin can be appropriately used for the purpose of improving various properties. For example, for the purpose of adjusting the viscosity and improving the printability, an acetalization reaction is performed using polyvinyl alcohol having a different degree of polymerization. A mixture of resins obtained by separately carrying out the above, and a mixture of polyvinyl alcohols having different degrees of polymerization at the raw material stage may be used.

  As described above, the present invention mainly uses an acetal resin as the binder resin of the thermal transfer image-receiving sheet, and does not fuse with the dye layer of the thermal transfer sheet during thermal transfer, that is, there is no abnormal transfer. Durability such as light resistance of the obtained printed matter is improved. In addition, when the degree of polymerization of the acetal resin used is 1000 or more and the acetal resin has a high molecular weight, the heat resistance of the receiving layer can be improved, and the printing speed of the thermal transfer printer can be increased. Accordingly, the dye layer and the receiving layer can be prevented from fusing even when the heat applied to the receiving layer during printing is increased. This is because the acetal-based resin in the receiving layer of the thermal transfer image-receiving sheet and the polyester-based resin having a bisphenol skeleton in the dye layer of the thermal transfer sheet used in the present invention are basically incompatible with each other, and are thus thermally fused. This is thought to be difficult. Furthermore, it is considered that by increasing the molecular weight of the acetal-based resin, the thermal responsiveness of the resin deteriorates, so that it becomes more difficult to heat-seal.

  Also, the binder resin of the receiving layer is mainly composed of acetal resin, and supplementarily halogenated polymers such as polyvinyl chloride and polyvinylidene chloride, polyvinyl acetate, ethylene vinyl acetate copolymer, vinyl chloride / vinyl acetate. Copolymers, polyacrylic esters, polystyrene, polystyrene acrylic and other vinyl resins, polyvinyl formal, polyvinyl butyral, polyvinyl acetal and other acetal resins, saturated and unsaturated polyester resins, polycarbonate resins, cellulose acetate, etc. Cellulose resins, polyolefin resins and the like can be additionally used.

In the receiving layer, a release agent can be added to the binder resin. This is performed by mixing a release agent for the purpose of preventing fusion with the dye layer or a decrease in printing sensitivity during thermal transfer. As the release agent used in the receiving layer in the present invention, conventionally known release agents, for example, solid waxes such as polyethylene wax, amide wax, Teflon (registered trademark) powder, fluorine-based, phosphate ester-based surface activity Any agent, silicone, etc. can be used. A particularly preferred release agent is a modified silicone, specifically,
1) Modified silicone oil side chain type,
2) Modified silicone oil both ends type,
3) Modified silicone oil one end type,
4) Modified silicone oil side chain both ends type,
5) Silicone graft acrylic resin, and 6) methylphenyl silicone oil.

  Modified silicone oils are divided into reactive silicone oils and non-reactive silicone oils. Examples of the reactive silicone oil include amino modification, epoxy modification, carboxyl modification, carbinol modification, methacryl modification, mercapto modification, phenol modification, one-end reactivity, and different functional group modification. Examples of the non-reactive silicone oil include polyether modification, methylstyryl modification, alkyl modification, higher fatty acid ester modification, hydrophilic special modification, higher alkoxy modification, higher fatty acid modification, and fluorine modification. Among the above silicone oils, reactive silicone oils of a type having a group that is reactive with the film-forming component may react with and bind to the hydroxyl group of the residue in the acetal resin, and appropriately use a curing agent, a catalyst, or the like. It is also possible to add and use.

  One or more release agents are used. Moreover, the addition amount of the release agent is preferably 0.5 to 30 parts by mass with respect to 100 parts by mass of the receiving layer forming resin. When the range of the addition amount is not satisfied, problems such as fusion between the sublimation type thermal transfer sheet and the receiving layer of the thermal transfer image receiving sheet or a decrease in printing sensitivity may occur. The receiving layer contains a binder resin and a release agent, and can be added with a curing agent and a catalyst. In addition, various additives can be added as necessary. Pigments and fillers such as titanium oxide, zinc oxide, kaolin, clay, calcium carbonate, fine powder silica and the like can be added for the purpose of improving the whiteness of the receiving layer and further enhancing the sharpness of the transferred image. Further, a known additive such as a plasticizer, an ultraviolet absorber, a light stabilizer, an antioxidant, a fluorescent whitening agent, and an antistatic agent can be added to the receiving layer as necessary.

The binder resin listed above, the mold release agent listed above, and additives, etc. are optionally added, and kneaded sufficiently with a solvent, diluent, etc. to prepare the receiving layer coating solution. This is applied on the above-mentioned base material by a forming means such as a gravure printing method, a screen printing method, a reverse roll coating method using a gravure plate, and dried to form a receiving layer. To do. The coating amount of the receiving layer is preferably 0.5g / m ² ~4.0g / m ² in dry. When the coating amount is less than 0.5 g / m ² at the time of drying, unevenness occurs in fixing of the dye, the dye acceptability is lowered, and even if the coating amount is excessive, it is a waste of raw materials, Moreover, a lot of drying time is required, and productivity and the like are reduced.

  In the thermal transfer image-receiving sheet of the present invention, a layer such as an antistatic layer, a cushion layer, a white pigment and an optical brightening agent is added between the base material and the receiving layer as required, such as an easily adhesive layer. May be. Moreover, you may form layers, such as an antistatic layer, a writing layer, a back surface layer, on the surface on the opposite side to the receiving layer formation side of a base material.

(Back layer)
A back layer 14 can be provided on the surface of the substrate opposite to the surface on which the receiving layer is provided in order to improve the transportability of the thermal transfer image receiving sheet and to prevent curling. As a back layer with such functions, added to resins such as acrylic resin, cellulose resin, polycarbonate resin, polyvinyl acetal resin, polyvinyl alcohol resin, polyamide resin, polystyrene resin, polyester resin, halogenated polymer As the agent, an acrylic filler, a polyamide filler, a fluorine filler, an organic filler such as polyethylene wax, an amino acid powder, or an inorganic filler such as silicon dioxide or metal oxide can be used. Moreover, what hardened | cured said resin with hardening | curing agents, such as an isocyanate compound, can also be used as a back surface layer. For the back layer, a back layer coating solution is prepared, and the same method as the above-described receiving layer forming means can be applied, and the coating amount of the back layer is 0.5 g / m ^{2 to} 5. It is preferably 0 g / m ² .

Next, an Example and a comparative example are given and this invention is further explained in full detail. In the text, “part” or “%” is based on mass unless otherwise specified.
First, the resin used in the receiving layer of the thermal transfer image receiving sheet was prepared by the method shown in the following Production Examples 01 to 04.

(Production Example 01)
A polyvinyl acetoacetal resin was produced as a binder component by the following method. First, 2790 g of pure water was placed in a 5 L separable flask, and 220 g of polyvinyl alcohol (polymerization degree 1700, saponification degree 98.8 mol%) was added thereto and completely dissolved. Next, the liquid temperature of this aqueous solution was kept at 20 ° C., 650 g of 35% hydrochloric acid was added thereto, and then the liquid temperature was lowered to 10 ° C., and 137 g of acetaldehyde was appropriately added to precipitate a colorless powder. Subsequently, after raising the temperature of the reaction system to 30 ° C. and keeping the temperature constant for 3 hours, neutralization by washing with water was performed to remove the catalyst and unreacted aldehyde to obtain a polyvinyl acetoacetal resin. (Acetalization degree: 74.1 mol%)

(Production Example 02)
A polyvinyl acetal resin was obtained in the same manner as in Production Example 01 except that polyvinyl alcohol having a polymerization degree of 2400 and a saponification degree of 99.2 mol% was used. (Acetalization degree: 70.5 mol%)

(Production Example 03)
In a 5 L separable flask, 2000 g of pure water was added, and 220 g of polyvinyl alcohol (polymerization degree 1700, saponification degree 98.8 mol%) was added thereto and completely dissolved. Next, the liquid temperature of this aqueous solution was kept at 20 ° C., and 130 g of 35% hydrochloric acid was added thereto, and then the liquid temperature was lowered to 10 ° C., and 125 g of butyraldehyde was appropriately added to precipitate a colorless powder. Thereafter, a butyral resin was obtained in the same manner as in Production Example 01. The degree of butyralization was 76 mol%.

(Production Example 04)
A polyvinyl acetal resin was obtained in the same manner as in Production Example 01 except that polyvinyl alcohol having a polymerization degree of 500 and a saponification degree of 98.8 mol% was used and the reaction temperature was 16 ° C. (Degree of acetalization 72.1 mol%)

Moreover, the polyester-type resin used with the dye layer of a thermal transfer sheet was prepared by the method shown in the following manufacture examples 1-3. The acid component and polyol component shown in the following example, and a trace amount of calcium acetate and antimony trioxide as a catalyst were placed in a Claisen flask reactor equipped with an air cooler, and the temperature was gradually raised under an N ₂ atmosphere. The reaction is carried out with stirring at this temperature for 1 hour, after which the reaction product is placed in a Pyrex® tube to completely shut off oxygen and 275 ° C. at 0.1-0.05 mmHg. Under conditions, a condensation reaction was performed for 2 hours to obtain a modified polyester resin.

(Production Example 1)
Acid component;
Terephthalic acid 70 parts isophthalic acid 30 parts polyol component;
Ethylene glycol 50 parts Bisphenol A 50 parts

(Production Example 2)
Acid component;
Terephthalic acid 40 parts isophthalic acid 30 parts sebacic acid 30 parts polyol component;
Ethylene glycol 40 parts Neopentyl glycol 40 parts Bisphenol B 20 parts

(Production Example 3) (Comparative resin)
Acid component;
Terephthalic acid 40 parts isophthalic acid 30 parts sebacic acid 30 parts polyol component;
Ethylene glycol 50 parts Neopentyl glycol 50 parts

Using the resin solutions obtained in Production Examples 01 to 04, the following four receiving layer coating solutions A to D were prepared.
(Receiving layer coating solution A)
Resin solution of Production Example 01 (based on solid content) 100 parts Silicone: 10 parts of polyether-modified silicone (trade name KF-615, Shin-Etsu Chemical Co., Ltd.)
Dilution with methyl ethyl ketone / toluene (mass ratio 1/1) was performed to adjust the solid content of the coating solution to 20%.

(Receiving layer coating solution B)
Resin solution of Production Example 02 (based on solid content) 100 parts Silicone: 5 parts of acrylic modified silicone (trade name: FS-730, manufactured by NOF Corporation)
Dilution with methyl ethyl ketone / toluene (mass ratio 1/1) was performed to adjust the solid content of the coating solution to 20%.

(Receiving layer coating solution C)
Resin solution of Production Example 03 (based on solid content) 100 parts Silicone: 8 parts of methylstyryl-modified silicone (trade name: KF-410, manufactured by Shin-Etsu Chemical Co., Ltd.)
Dilution with methyl ethyl ketone / toluene (mass ratio 1/1) was performed to adjust the solid content of the coating solution to 20%.

(Receiving layer coating solution D)
Resin solution of Production Example 04 (solid content standard) 100 parts Silicone: Alkyl-modified silicone 10 parts (trade name: KF-412 manufactured by Shin-Etsu Chemical Co., Ltd.)
Dilution with methyl ethyl ketone / toluene (mass ratio 1/1) was performed to adjust the solid content of the coating solution to 20%.

Next, using the resin solutions obtained in Production Examples 1 to 3, coating solutions having the following three dye layer conditions were prepared.
(Dye layer condition <1>)
・ Yellow dye layer coating solution;
Resin solution of Production Example 1 (solid content basis) 4.5 parts C.I. I. Disperse Yellow-231 7 parts Methyl ethyl ketone 45 parts Toluene 37 parts Cyclohexanone 5.5 parts Release agent (KF615) 1 part

・ Cyan dye layer coating solution;
Resin solution of production example 1 (solid content basis) 5 parts C.I. I. Solvent Blue-63 7 parts Methyl ethyl ketone 45 parts Toluene 39 parts Cyclohexanone 3 parts Mold release agent (KF615) 1 part

(Dye layer condition <2>)
Both the yellow dye layer coating solution and the cyan dye layer coating solution have the same composition except that the resin solution in the composition of the above dye layer condition <1> used the resin of Production Example 2.
(Dye layer condition <3>)
Both the yellow dye layer coating solution and the cyan dye layer coating solution have the same composition except that the resin solution used in Production Example 3 is used in the composition of the above dye layer condition <1>.

(Experimental example 1)
As a base material, white PET (Lumilar E63S manufactured by Toray Industries, Inc.) having a thickness of 50 μm is coated with urethane adhesive (Takeshi Mitsui) on both sides of coated paper (Oji Paper Co., Ltd. OK Top Coat; 127.9 g / m ² ). The base material pasted by Chemical Co., Ltd. product Takelac A-969V / Takenate A-5 = 3/1, coating amount: 4 g / m ² (after drying)) was used. The receiving layer coating solution A prepared above was applied to one surface of the substrate with a bar coater so that the coating amount was 2.0 g / m ² (after drying), and dried (120 ° C., 3 minutes) Thus, a thermal transfer image receiving sheet was produced.

Moreover, as a base material sheet, a yellow dye layer coating solution and a cyan dye layer coating solution of the dye layer condition <1> prepared above on a polyethylene terephthalate film (PET) having a thickness of 4.5 μm at 40 ° C. The mixture was heated and applied with a bar coater so that each coating amount was 1.0 g / m ² (after drying) and dried (80 ° C., 5 minutes) to prepare a thermal transfer sheet. In addition, a heat resistant slipping layer coating solution having the following composition was applied in advance to the other surface of the substrate sheet by gravure coating and dried so that the dry coating amount was 1.0 g / m ^2. A sex layer was formed.

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

(Experimental example 2)
A thermal transfer image receiving sheet was prepared in the same manner as in Experimental Example 1 except that the receiving layer coating solution was changed to the receiving layer coating solution B prepared above in the preparation conditions of the thermal transfer image receiving sheet of Experimental Example 1. . The same thermal transfer sheet as in Experimental Example 1 was used.

(Experimental example 3)
A thermal transfer image receiving sheet was prepared in the same manner as in Experimental Example 1 except that the receiving layer coating solution was changed to the receiving layer coating solution C prepared above in the preparation conditions of the thermal transfer image receiving sheet of Experimental Example 1. . The same thermal transfer sheet as in Experimental Example 1 was used.

(Experimental example 4)
A thermal transfer image receiving sheet was prepared in the same manner as in Experimental Example 1 except that the receiving layer coating solution was changed to the receiving layer coating solution D prepared above in the preparation conditions of the thermal transfer image receiving sheet of Experimental Example 1. . The same thermal transfer sheet as in Experimental Example 1 was used.

(Experimental example 5)
Except for changing the yellow dye layer coating liquid and the cyan dye layer coating liquid to those of the above dye layer condition <2> in the preparation conditions of the thermal transfer sheet of Experimental Example 1, the same as in Experimental Example 1 Thus, a thermal transfer sheet was produced. Further, the same thermal transfer image receiving sheet as in Experimental Example 1 was used.

(Experimental example 6)
Except for changing the yellow dye layer coating liquid and the cyan dye layer coating liquid to those of the above dye layer condition <2> in the preparation conditions of the thermal transfer sheet of Experimental Example 2, the same as in Experimental Example 2 Thus, a thermal transfer sheet was produced. Further, the same thermal transfer image receiving sheet as in Experimental Example 2 was used.

(Experimental example 7)
Except for changing the yellow dye layer coating solution and the cyan dye layer coating solution to those of the above dye layer condition <2> in the preparation conditions of the thermal transfer sheet of Experimental Example 3, the same as Experimental Example 3 Thus, a thermal transfer sheet was produced. Further, the same thermal transfer image receiving sheet as in Experimental Example 3 was used.

(Experimental example 8)
Except for changing the yellow dye layer coating liquid and the cyan dye layer coating liquid to those of the above dye layer condition <2> in the preparation conditions of the thermal transfer sheet of Experimental Example 4, the same as in Experimental Example 4 Thus, a thermal transfer sheet was produced. Further, the same thermal transfer image receiving sheet as in Experimental Example 4 was used.

(Experimental example 9)
Except for changing the yellow dye layer coating liquid and the cyan dye layer coating liquid to those of the above dye layer condition <3> in the preparation conditions of the thermal transfer sheet of Experimental Example 1, the same as in Experimental Example 1 Thus, a thermal transfer sheet was produced. Further, the same thermal transfer image receiving sheet as in Experimental Example 1 was used.

(Experimental example 10)
Except for changing the yellow dye layer coating liquid and the cyan dye layer coating liquid to those of the above dye layer condition <3> in the preparation conditions of the thermal transfer sheet of Experimental Example 2, the same as in Experimental Example 2 Thus, a thermal transfer sheet was produced. Further, the same thermal transfer image receiving sheet as in Experimental Example 2 was used.

(Experimental example 11)
Except for changing the yellow dye layer coating liquid and the cyan dye layer coating liquid to those of the above dye layer condition <3> in the preparation conditions of the thermal transfer sheet of Experimental Example 3, the same as in Experimental Example 3 Thus, a thermal transfer sheet was produced. Further, the same thermal transfer image receiving sheet as in Experimental Example 3 was used.

(Experimental example 12)
Except for changing the yellow dye layer coating liquid and the cyan dye layer coating liquid to those of the above dye layer condition <3> in the preparation conditions of the thermal transfer sheet of Experimental Example 4, the same as in Experimental Example 4 Thus, a thermal transfer sheet was produced. Further, the same thermal transfer image receiving sheet as in Experimental Example 4 was used.

(Evaluation)
Next, as described below, the conditions for combining the thermal transfer sheet and the thermal transfer image-receiving sheet prepared in each of the above experimental examples are as shown in each experimental example, and the print density and product appearance are investigated by the following methods. did.

<Print density>
Prepare two types of thermal transfer sheets that are allowed to stand in a room and those that are stored for 96 hours in an environment of temperature 40 ° C. and humidity 90% RH, combined with the thermal transfer image-receiving sheet corresponding to each experimental example, and dye layer And the receiving layer were overlapped, and printing was performed under the following conditions, and the print density as the reflection density was measured with a Macbeth reflection densitometer RD-918. That is, the print density of the thermal transfer sheet before and after storage at high temperature and high humidity was examined.

(Printing conditions)
Heating element average resistance: 5179 (Ω)
Main scanning direction printing density; 300 dpi
Sub-scanning direction print density; 300 dpi
Applied voltage: 24 (V)
1 line cycle; 2 (msec.)
Printing start temperature; 40 (° C)
Applied pulse (gradation control method); using a multi-pulse test printer that can vary the number of divided pulses from 0 to 255 in one line period and having a pulse length obtained by equally dividing one line period into 256 The duty ratio of the divided pulse was fixed to 70%, and the number of pulses per line period was divided into 15 from 0 to 255. Thereby, different energy can be given to 15 steps. The above printing conditions were carried out at a printable speed at a voltage at which the voltage was reduced and the receiving layer did not lose heat as much as possible.

  About the printed matter in each of the above experimental examples, the reflection density at the 240th gradation (shadow portion) was measured.

<Product appearance>
Prepare two types of thermal transfer sheets, one that is left indoors and the other that is stored for 96 hours in an environment of temperature 40 ° C. and humidity 90% RH, and observe the state of the dye layer of each thermal transfer sheet with the naked eye. ,evaluated. That is, the appearance of the product before and after high-temperature storage of the thermal transfer sheet was examined. The evaluation criteria are as follows.
○: Dye does not precipitate and there is no problem.
X: Precipitation of the dye is observed, which is poor.

For the thermal transfer recording materials prepared in the above experimental examples 1 to 4, the printing conditions are changed to the following conditions, and the printing density and releasability, and the reliability of light resistance, heat resistance, moisture resistance, and blocking resistance are assured. The test was evaluated.
(Printing conditions)
Heating element average resistance: 5179 (Ω)
Main scanning direction printing density; 300 dpi
Sub-scanning direction print density; 300 dpi
Applied voltage: 32 (V)
1 line period; 1 (msec.)
Printing start temperature; 40 (° C)
Applied pulse (gradation control method): Using a multi-pulse test printer that can vary the number of divided pulses from 0 to 255 in one line period and having a pulse length obtained by equally dividing one line period into 256 The duty ratio of the divided pulses was fixed at 90%, and the number of pulses per line period was divided into 15 from 0 to 255. Thereby, different energy can be given to 15 steps. The above printing conditions are assumed for high-speed printing.

The evaluation of the reliability test of the above print density and releasability, and light resistance, heat resistance, moisture resistance, and blocking resistance was examined by the following method.
<Print density>
About the printed matter in each of the above experimental examples, the reflection density at the 240th gradation (shadow portion) was measured.

<Releasability>
Under the printing conditions when the applied voltage is 32 V, the thermal transfer image-receiving sheet and the thermal transfer sheet are heat-sealed when the dye layer of the thermal transfer sheet and the receiving layer of the thermal transfer image-receiving sheet in each experimental example are superimposed and printed. The mold release property was examined to see if there was any problem when peeling by hand. The criteria for evaluation are as follows.
○: There is almost no resistance when peeling, and there is no problem caused by thermal fusion between the thermal transfer image-receiving sheet and the thermal transfer sheet.
(Triangle | delta): Although there is some resistance at the time of peeling, there is no problem resulting from heat fusion.
X: It is heat-sealed and is difficult to peel off.

<Light resistance>
About the printed matter obtained on the printing conditions in the case of said applied voltage 32V, light resistance was evaluated with the xenon fade meter of the following conditions.
(Conditions for light resistance evaluation)
・ Irradiation tester: Ci35 manufactured by Atlas
・ Light source: Xenon lamp ・ Filter: Inside = IR filter
Outside = soda lime glass / black panel temperature: 45 (° C)
・ Irradiation intensity: Measurement value at 1.2 (W / m ² ) −420 (nm) ・ Irradiation energy: Integrated value at 400 (kJ / m ² ) −420 (nm)

  Next, the change in the optical reflection density of the Cy component of the cyan image before and after irradiation under the above light resistance conditions was measured with an optical densitometer (Macbeth RD-918 (using a red filter) manufactured by Macbeth), and the optical reflection before irradiation. For steps with a concentration of around 1.0, the remaining rate was calculated according to the following formula, and light resistance was evaluated based on the following evaluation criteria based on this remaining rate.

Residual rate (%) = (optical reflection density after irradiation / optical reflection density before irradiation) × 100
(Evaluation criteria)
○: Residual rate is 80% or more and light resistance is good.
Δ: Residual rate is 60% to 70%, and light resistance is slightly inferior.

<Heat resistance>
About the printed matter obtained on the printing condition in the case of the said applied voltage of 32V, after leaving it to stand in a 60 degreeC environment for one week, the state of the printed matter was observed. The criteria for the evaluation are as follows.
○: No defects such as bleeding are found in the print portion, which is good.
Δ: Some blur is observed in the print portion, and the heat resistance is slightly inferior.

<Moisture resistance>
About the printed matter obtained on the printing conditions in the case of the said applied voltage of 32V, after leaving it to stand in the environment of 50 degreeC and 80% RH for 100 hours, the state of the printed matter was observed. The criteria for the evaluation are as follows.
○: No defects such as bleeding are found in the print portion, which is good.
Δ: Slight bleeding is observed in the print area, and the moisture resistance is slightly inferior.
X: Bleeding is observed in the printed part and the moisture resistance is poor.

<Blocking resistance>
About the printed matter obtained under the printing conditions in the case of the applied voltage of 32 V, the image-formed image receiving surface and the back surface of the other printed matter are overlapped with each other in the printed matter of each experimental example, This was left in a 60 ° C. oven for 48 hours with a load of 20 kg / cm ² in a state of being sandwiched between 150 μm thick synthetic paper (Yupo FPG # 150 manufactured by Oji Yuka Co., Ltd.) and then superposed. The image receiving surface and the back surface were peeled off, and blocking resistance was examined according to the following evaluation criteria.
○: Not blocking.
Δ: Partially blocking.

Table 1 below shows the evaluation results of the print density and the product appearance in the above Experimental Examples 1-12. However, the results shown in Table 1 are the results obtained by examining the yellow dye layer, and the same tendency is observed for the results obtained by examining the cyan dye layer.

  In Table 1 shown above, in Experimental Examples 9 to 12, the conditions of the dye layer are those that do not contain a polyester-based resin having a bisphenol skeleton, and the print density after storing the thermal transfer sheet at high temperature and high humidity. There is a significant decrease.

The evaluation results of the print density, releasability, and reliability test in Experimental Examples 1 to 4 are shown in Table 2 below. However, the results shown in Table 2 are those for the dye layer condition <1> described above, and are printed using a yellow dye layer, but even when printed using a cyan dye layer, the dye layer condition is also shown. The same tendency can be seen with <2> and <3>.

  In Table 2 shown above, in Experimental Example 4, the condition of the receiving layer contains an acetal resin, but the degree of polymerization of the acetal resin is less than 1000, Releasability is poor and heat fusion occurs. Further, the evaluation of moisture resistance of the printed matter is poor.

It is the schematic which shows one Embodiment of the thermal transfer recording material of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermal transfer recording material 2 Thermal transfer sheet 3 Base material sheet 4 Dye layer 5 Heat-resistant slip layer 11 Thermal transfer image receiving sheet 12 Base material 13 Receiving layer 14 Back surface layer

Claims (5)

  It consists of a thermal transfer sheet provided with a dye layer on at least one side of the base sheet, and a thermal transfer image receiving sheet provided with a receiving layer on at least one side of the base, and the dye layer and the receiving layer are overlapped, In the thermal transfer recording material capable of transferring the dye in the dye layer to the receiving layer by heating means, the receiving layer of the thermal transfer image receiving sheet contains an acetal resin, and the dye layer of the thermal transfer sheet has a bisphenol skeleton A thermal transfer recording material comprising: The acetal resin of the receiving layer is represented by the following general formula, the degree of polymerization of the acetal resin is 1000 or more, and the mol% of the acetal part is 50% or more based on the whole resin. The thermal transfer recording material according to claim 1, wherein 80 mol% or more of the acetal portion is polyvinyl acetoacetal or polyvinyl butyl acetal.

In the above formula, R represents an aryl group, an aralkyl group, or an aryl group-containing vinyl group which may have a substituent, and l, m, and n represent mol% of each structural unit, and 50 <l <85. 10 <m <50 and 0 <n <30.   The thermal transfer recording material according to claim 1, wherein the dye layer contains a polyester resin using a polyol having a bisphenol skeleton as an alcohol component.   The thermal transfer recording material according to claim 1, wherein the receiving layer further contains a release agent. 4. The thermal transfer recording material according to claim 1, wherein the dye layer further contains a release agent.

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