JP2009023135A - Support for thermal transfer, and acceptance sheet for thermal transfer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ecological resin-coated support for thermal transfer which is excellent in blocking properties between acceptance sheets for thermal transfer after printer printing and paste-adhesiveness of a back coating layer, and which makes the natural pulp center of manufacture and the acceptance sheet for thermal transfer. <P>SOLUTION: In the resin-coated support for thermal transfer, paper consisting mainly of natural pulp serves as a substrate, a surface opposite to a surface on which at least the acceptance layer of the substrate is formed is coated with a resin layer containing a film-formable resin, and a back coating layer is formed on the surface opposite to the surface on which the acceptance layer is formed. The back coating layer is made of a silicone-modified aqueous acrylic urethane copolymer resin, the copolymerization ratio (mass%) of an acrylic resin to a urethane resin in the copolymer resin is 50:50-20:80, and the content of a spherical pigment in the total resin contained in the back coating layer is 20-40 mass%. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is an environment-friendly resin-coated thermal transfer centering on natural pulp, which is excellent in blocking property (hereinafter referred to as “sprinkling property”) between thermal transfer receiving sheets after printer printing and adhesive adhesiveness of the backcoat layer. The present invention relates to a support for heat transfer and a receiving sheet for thermal transfer.

  In recent years, as one means of color hard copy, apparatuses using a thermal transfer recording method have become widespread due to advantages such as light weight, compactness, no noise, excellent operability and maintainability. This thermal transfer recording method is roughly classified into two types, a heat melting type, a heat transfer type, and a sublimation type. In particular, the latter is excellent in the reproducibility of a multicolor gradation image and is printed using a sublimation type thermal transfer printer. The principle of such a sublimation type thermal transfer printer is that an image is converted into an electrical signal, and further, this electrical signal is converted into a thermal signal by a thermal head, and a thermal transfer medium coated with a heat transferable dye (hereinafter, referred to as a thermal transfer medium). Information is recorded by heating the ink donor sheet) and transferring the dye from the ink donor sheet to the receiving layer of the thermal transfer receiving sheet by sublimation or diffusion in the medium.

  Conventionally, a film base has been generally used as a support for the above-described thermal transfer receiving sheet. Since these are mainly made of synthetic resin material as the base material, if the thickness is increased for use in the above-mentioned applications, the strength and durability are relatively good, but they are related to the recent disposal. It could not be said that it was a preferred material because of problems such as environmental impact, generation of harmful substances during incineration, and damage to the incinerator. In addition, when paper or coated paper base is used as the support, the environmental load related to disposal is reduced, but the strength and durability are inferior, and smoothness when used as a thermal transfer receiving sheet is ensured. It was difficult. Accordingly, as a material for an environmentally friendly support that compensates for both of these weak points, a resin-coated support having a film-forming resin such as polyethylene laminated on at least one surface of paper has attracted attention.

  In such a resin-coated support for thermal transfer, in recent years, from the viewpoint of increasing the printing speed, it is required to improve the spreadability of the thermal transfer receiving sheet after printer printing. For example, a receiving sheet containing a silicone compound component and particles bonded to each other by graft polymerization or block polymerization in a polymer in the binder of the back layer is described, but it has excellent transportability in a printer. However, it was not suitable at all in terms of the adhesiveness between the tearability and the water-soluble glue (see, for example, Patent Document 1).

  In addition, although there is a description of a thermal transfer receiving sheet in which the back layer is composed of a hydrophilic porous layer and a conductive release layer, it is not possible to ensure sufficient squeezing between the thermal transfer receiving sheets after printer printing. In addition, providing two layers on the back layer is disadvantageous in terms of cost, and further, the step of applying a solvent-based resin is not preferable in the working environment (see, for example, Patent Document 2).

Further, regarding the improvement of the adhesiveness of the backcoat layer, for example, from the viewpoint of improving the adhesiveness of a postage stamp or the like, a dye thermal transfer containing nylon resin particles, barium sulfate and a higher fatty acid salt in the back coating layer. There are descriptions of receiving sheets, dye thermal transfer receiving sheets containing nylon resin particles, higher fatty acid salts and partially saponified polyvinyl alcohol, and dye thermal transfer receiving sheets containing cationic pigments, higher fatty acid salts and adhesives, all of which are water-soluble. Although the adhesiveness of the paste has been improved to some extent, it has not been suitable for the spreadability (see, for example, Patent Documents 3 to 5).
Japanese Patent No. 3789624 Japanese Patent Laid-Open No. 11-165469 JP 2000-335120 A JP 2001-199172 A JP 2001-213057 A

  The present invention is an environment-friendly resin-coated thermal transfer support mainly made from natural pulp, which has excellent spreadability between receiving sheets for thermal transfer after printer printing and adhesive adhesion of a backcoat layer, and the same. The present invention relates to a thermal transfer receiving sheet.

As a result of intensive studies on such problems, the present inventors have found the following invention.
That is, the invention of claim 1 is for thermal transfer, in which paper having natural pulp as a main component is used as a substrate, and at least the surface opposite to the surface on which the receiving layer of the substrate is provided is coated with a resin layer containing a film-forming resin. The support has a back coat layer on the surface opposite to the surface on which the receiving layer is provided, and the back coat layer is made of a silicone-modified water-based acrylic urethane copolymer resin, and the acrylic resin in the copolymer resin The copolymerization ratio (% by mass) of the urethane resin is 50:50 to 20:80, and the spherical pigment is contained in an amount of 20 to 40% by mass with respect to the total resin amount contained in the backcoat layer. This is a resin-coated support for thermal transfer.

  The invention according to claim 2 is the support for thermal transfer according to claim 1, wherein the glass transition temperature of the acrylic resin contained in the back coat layer is 30 ° C. or higher.

  The invention according to claim 3 is the support for thermal transfer according to claim 1 or 2, wherein the spherical pigment contained in the back coat layer has an average particle size of 0.5 to 3.0 μm.

  According to a fourth aspect of the present invention, there is provided a thermal transfer receiving sheet, wherein at least a receiving layer is formed on the thermal transfer support according to the first to third aspects.

  INDUSTRIAL APPLICABILITY According to the present invention, an environment-friendly resin-coated thermal transfer support centering on natural pulp and a thermal transfer receiving sheet, which have excellent spreadability between thermal transfer receiving sheets after printer printing and adhesive adhesiveness of a backcoat layer Can be provided.

Hereinafter, the present invention will be described in detail.
The object of the present invention relates to a thermal transfer support excellent in the spreadability between thermal transfer receiving sheets after printer printing and the adhesiveness of the backcoat layer, and the thermal transfer receiving sheet using the same. As a result, in order to satisfy these performances, it was found that the types and ratios of the binder resins used in the backcoat layer and the use of spherical pigments are the most effective means.

  When printing a thermal transfer receiving sheet, the ink donor sheet is adhered and heated to the thermal transfer receiving sheet, and the heat transferable dye is sublimated or diffused in the medium, so that the dye is transferred from the ink donor sheet to the receiving layer of the thermal transfer receiving sheet. The information is recorded by transferring. Recently, after forming an image with yellow, magenta, and cyan dyes, a protective layer is transferred for the purpose of improving the durability of the image. As described above, when the ink donor sheet and the thermal transfer receiving sheet are subjected to the process of being brought into close contact with each other and peeled off, the front and back surfaces of the thermal transfer receiving sheet are charged by peeling charging. In addition, there is a problem that the thermal transfer receiving sheets adhere to each other after printing due to friction between the thermal transfer receiving sheets during conveyance, contact with the roll when the thermal transfer receiving sheet passes through the printer, or peeling charging. Cause the problem of whispering.

  In recent years, the adoption of the thermal transfer system has made it easy to obtain high-quality and high-definition images comparable to conventional silver halide photography. so. Mailing this has also become widespread. When used as a postcard, it is necessary to print the address, address, etc. on the back side and affix a stamp. In particular, there is an increasing demand for adhesiveness to water-soluble glue that is widely used in general households. .

  As a result of studying these problems by the present inventors, it is effective to use a silicone-modified water-based acrylic urethane copolymer resin for the backcoat layer, and to improve adhesiveness. It has been found effective to increase the copolymerization ratio of the urethane resin. The silicone-modified acrylic urethane copolymer resin is a binder resin with excellent heat resistance and excellent slipperiness, and the reason is not clear, but the silicone-modified acrylic urethane copolymer resin is used as the backcoat layer. By using this, the charge potential of the backcoat layer, which is normally largely charged to the negative side, is shifted to the positive side. As a result, the resin itself has a special charging performance that the backcoat layer can be remarkably suppressed from being charged. It is possible to improve the spreadability of the receiving sheet for thermal transfer after printing that occurs due to peeling or peeling. Moreover, it became clear that by increasing the copolymerization ratio of the urethane resin, it showed excellent performance especially in the adhesiveness of water-soluble paste while suppressing the problem of scratching property.

  Furthermore, by adding spherical pigments, the slipperiness of the backcoat layer can be further improved, and by adding pigments to the surface with appropriate irregularities, glue adhesion can be improved at the same time by anchoring effect. .

  From the above, the blending ratio of these materials is adjusted, and as a result, it is composed of a silicone-modified water-based acrylic urethane copolymer resin, and the copolymerization ratio (% by mass) of the acrylic resin and urethane resin in this copolymer resin. By using a thermal transfer support having a back coat layer that is 20:40 to 20% by mass with respect to the total amount of resin that is 50:50 to 20:80 and the spherical pigment is contained in the back coat layer, To invent an environmentally friendly resin-coated support for thermal transfer and a thermal transfer receiving sheet mainly made from natural pulp, which are excellent in the spreadability between the thermal transfer receiving sheets after printer printing and the adhesiveness of the backcoat layer. It came.

  The silicone-modified water-based acrylic urethane resin used in the backcoat layer of the present invention can be used without any problem as long as it is generally used. The silicone-modified water-based acrylic urethane resin is not particularly limited as long as it is a water-based acrylic urethane resin and has a siloxane bond in the molecule, and the resin having a content corresponding to the application may be used. For example, an acrylic urethane resin can be obtained by reacting an acrylic polyol and a polyisocyanate, but an acrylic urethane resin having a siloxane bond in the molecule can be obtained by using a silicone-modified acrylic polyol as the acrylic polyol. By using a polyisocyanate modified with silicone as the polyisocyanate, an acrylic urethane resin having a siloxane bond in the molecule can be obtained. In addition, when an acrylic polyol and a polyisocyanate are reacted, an acrylic urethane resin having a siloxane bond in the molecule can be obtained by using a silicone polyol having both ends and side chains of polydimethylsiloxane as hydroxyl groups. .

  The copolymerization ratio (mass%) of the acrylic resin and the urethane resin in the silicone-modified aqueous acrylic urethane copolymer resin used in the backcoat layer of the present invention is in the range of 50:50 to 20:80. When there are more acrylic resins than this blending rate (or less urethane resins than this blending rate), glue adhesion becomes a problem, and when there are more urethane resins than this blending (or less acrylic resins than this blending rate) The problem is that it is ugly. In addition, the acrylic resin component of each component ratio in the said copolymerization ratio is a mass ratio (%) of the acrylic polymer in a copolymer, and a urethane resin component is a mass ratio (% of the urethane polymer in a copolymer). ).

  The glass transition temperature of the acrylic resin in the acrylic urethane copolymer resin used for the backcoat layer of the present invention is preferably 30 ° C. or higher, and more preferably in the range of 30 ° C. to 70 ° C. If the temperature is lower than 30 ° C, heat resistance may be insufficient, which may cause a problem in sprinkling. If the temperature is higher than 70 ° C, the effect of improving the sprinkling is saturated, and adhesion between the binder and the support during processing. In some cases, the back coat layer may be peeled off due to insufficient properties.

  Specifically, the glass transition temperature of the acrylic resin referred to in this specification is a calculation formula of the theoretical Tg of the copolymer (1 / Tg = C1 / Tg1 + C2 / Tg2 +... + Cn / Tgn, where Tg is Copolymer theory Tg, Cn is the weight ratio of the n-th monomer n contained in the monomer mixture, Tgn is the Tg of the homopolymer of the n-th monomer n, and n is the copolymer weight It is the kind of monomer constituting the coalesced and can be obtained by calculation using a positive integer). Moreover, the value described in literature etc. can be used for Tg of a monomer homopolymer.

The spherical pigment used in the backcoat layer of the present invention can be used without particular limitation regardless of inorganic type or organic type, and an organic type spherical pigment can be more preferably used. As the definition of the spherical shape, any commercially available product can be used without any problem as long as it is described as being spherical or spherical, or can be confirmed as a spherical shape by a microscope. By using spherical pigments, triboelectric charge generated during conveyance inside the printer is reduced, and blocking properties between the thermal transfer receiving sheets after printing can be reduced. As a result, the adhesiveness can be improved at the same time. The blending ratio of the spherical pigment is a solid content ratio and is in the range of 20 to 40% by mass with respect to the total binder resin used in the backcoat layer. Outside this range, problems arise in the spreadability and adhesiveness. The average particle diameter of the spherical pigment is not particularly limited, but if a small average particle diameter is used, the number of contact points with the receiving layer of the thermal transfer receiving sheet increases, so the frictional charge between the thermal transfer receiving sheets is large. Therefore, the effect of improving the spreading property is not sufficiently exhibited. On the other hand, when one having a large average particle diameter is used, the adhesion area of the spherical pigment in the backcoat layer becomes small, and a problem of peeling off may occur. In view of this point, the average particle diameter of the spherical pigment is 0.5% in order to reduce the frictional charge generated during conveyance inside the printer and to reduce the blocking property between the thermal transfer receiving sheets after printing. The thing of-3 micrometers is preferable, and the thing of 1.0-2.0 micrometers is more preferable.
Specifically, Saiden Chemical's Cybinol series, Sekisui Plastics's MBX series, BMX series, SBX series, MB-C series, Sumitomo Seika's flow beads, Shin-Etsu Chemical's KMP series, etc. Can be mentioned.

  The average particle diameter (d50) referred to in this specification is specifically determined as a volume median diameter d50 (μm) of particles measured using a laser particle size distribution meter MICROTRAC MT3000 (manufactured by Nikkiso Co., Ltd.). Can do.

  In addition to the above, those commercially available as an antistatic agent can be used in the backcoat layer of the present invention for the purpose of antistatic. Antistatic agents can be classified into inorganic types using the metal itself, or chemically synthesized organic types. In the present invention, the antistatic agent can be used for aqueous addition and aqueous coating. Can be used without any problem. In addition, any commonly used dye or lubricant can be added without particular limitation.

The coating amount of the backcoat layer of the present invention is not particularly limited in the range of 0.1 to 5.0 g / ^{m 2,} preferably 0.1 to 2.0 g / ^{m 2.} If the coating amount is too large, the cost becomes unsuitable, and if the coating amount is too small, sufficient performance cannot be obtained.

  The method for providing the backcoat layer of the support for thermal transfer of the present invention is not particularly limited, but it is opposite to the side on which the image forming layer is provided after coating the resin layer on the traveling base paper surface and before winding. It is preferable to carry out by a so-called on-machine method in which a backcoat layer is provided by coating and drying a backcoat solution on the resin layer side. Moreover, after winding up resin-coated paper, after storing winding as needed, it can also carry out by what is called an off-machine method which provides a backcoat layer again. Examples of the apparatus for applying the back coat liquid include an air knife coater, a roll coater, a bar coater, a wire bar coater, a blade coater, a slide hopper coater, a curtain coater, a gravure coater, a flexographic gravure coater, and combinations thereof.

  Prior to coating, the backcoat layer may be subjected to other activation treatment such as flame treatment in addition to the corona discharge treatment on the resin surface. Various types of drying equipment such as straight tunnel dryers, arch dryers, air loop dryers, sine curve air float dryers, infrared dryers, heating dryers, microwave dryers, etc. A drying device can be mentioned. Moreover, although drying conditions are arbitrary, generally it is performed at 40 to 150 degreeC for several seconds to 10 minutes.

  As the pulp constituting the base paper used for the thermal transfer support of the present invention, JP-A-58-37642, JP-A-60-67940, JP-A-60-69649, JP-A-61. It is advantageous to use an appropriately selected natural pulp as described or exemplified in Japanese Patent No. -35442. Natural pulp was subjected to normal bleaching treatment of chlorine, hypochlorite, chlorine dioxide bleaching, alkali extraction or alkali treatment, and if necessary, oxidative bleaching treatment with hydrogen peroxide, oxygen, etc., and combinations thereof. Wood pulp of softwood pulp, hardwood pulp, mixed softwood hardwood pulp is used, and various pulps such as kraft pulp, sulfite pulp, soda pulp, and other recycled pulp (spent paper pulp) can be used.

  Various additives can be incorporated into the base paper used in the practice of the present invention when preparing the paper slurry. As additives, commonly used sizing agents, dry paper strength enhancers, wet paper strength enhancers, fillers, fixing agents, pH adjusters, and others, such as JP-A-63-204251 and JP-A-1-266537, are used. It is advantageous to appropriately combine color pigments, colored dyes, fluorescent brighteners, etc. described or exemplified in the publications.

  In the base paper, a composition comprising various water-soluble polymers or hydrophilic colloids or latexes, antistatic agents, pigments, pH adjusters, and other additives is subjected to size press or tab size press or blade coating, It can be contained by coating such as air knife coating.

The density of the base paper thermal transfer support in the present ^invention, preferably in the range of ^{0.80g / cm 3 ~1.15g / cm 3} , a range of 0.85g / cm ³ ~1.05g / cm 3 is more preferable. If the density of the base paper is less than 0.80 g / cm ³ , a thermal transfer support with good surface quality and excellent smoothness cannot be obtained. When the density of the base paper is greater than 1.15 g / cm ^{3 and} the basis weight of the base paper is constant, the thermal transfer support becomes weak. In addition, when the density of the base paper is larger than 1.15 g / cm ^{3 and} the paper thickness of the support is kept constant, there is an economical problem that the basis weight of the base paper has to be increased. For the basis weight of the base paper used in the practice of the present invention is not particularly limited, the basis ^weight, preferably from ^{70g / m 2 ~220g / m 2} .

  At least one surface of the base paper of the thermal transfer support in the present invention is covered with a resin layer containing a resin capable of forming a film. The resin capable of forming a film is preferably a thermoplastic resin such as a polyolefin resin, a polycarbonate resin, a polyester resin, a polyamide resin, and a mixture thereof. Among them, the above-described polyolefin resin and / or polyester resin is preferable from the viewpoint of melt extrusion coating property. More preferred are polyethylene resins. Moreover, you may coat | cover with the resin layer which consists of an electron beam curable resin as described in Japanese Patent Publication No. 60-17104, or an example.

  The support for thermal transfer in the present invention is for the front resin layer when the resin in the front resin layer and the back resin layer is a thermoplastic resin, preferably a polyolefin resin, particularly preferably a polyethylene resin on the running base paper. In addition, the resin composition for the back resin layer is produced by a so-called melt extrusion coating method in which a resin composition for a back resin layer is cast and coated from the slit die into a film using a melt extruder. Moreover, it is preferable to subject the base paper to activation treatment such as corona discharge treatment and flame treatment before coating the resin composition on the base paper. Further, the surface resin layer surface can be processed into a glossy surface, a fine rough surface described in Japanese Patent Publication No. Sho 62-19732, a matte surface or a silky surface, and the back resin layer is usually processed into a matte surface. preferable.

  The thickness of the front and back resin layers of the thermal transfer support in the present invention is not particularly limited, but the thickness of the front resin layer is useful in the range of 9 to 60 μm, preferably 12 μm. It is in the range of ˜45 μm. The thickness of the back resin layer is useful in the range of 5 μm to 60 μm, but is preferably in the range of 8 μm to 40 μm.

  Various additives can be contained in the front and back resin layers of the thermal transfer support in the present invention. Examples of the additive include generally used fillers, fatty acid metal salts, antioxidants, dyes, fluorescent brighteners, ultraviolet absorbers, and the like. These additives are preferably contained as a resin master batch or compound. In particular, as a method for incorporating these additives into the compound resin composition for the resin layer used in the practice of the present invention, it is added in advance to the high-density polyethylene resin and the low-density polyethylene resin or the medium-density polyethylene resin, or A masterbatch can be added at the time of preparation of the compound resin, or a masterbatch added to the resin at a high concentration in advance, and this masterbatch can be added to the resin at the time of melt extrusion coating.

A gelatin subbing layer can be provided on the side of the support for thermal transfer of the present invention where the receiving layer is provided in order to improve the hydrophobic resin surface to be hydrophilic. Examples of the gelatin for the subbing layer include various types such as lime-processed gelatin, acid-processed gelatin, enzyme-processed gelatin, and gelatin derivatives such as gelatin reacted with a dibasic acid anhydride. In addition, other hydrophilic polymers such as polyvinyl alcohol and starch can be used in combination with gelatin. No particular limitation is imposed on the coating amount of the undercoat layer, a coating amount of gelatin, the aqueous coating liquid of 0.1 wt% to 10 ^{wt% 1g / m 2 ~40g / m} 2 coating It is preferable to do this.

  In order to further improve the wettability of the surface resin layer surface, the undercoat layer may contain an anionic surfactant or an inorganic compound containing Cr (III) ions or Al (III) ions in addition to gelatin. It is particularly preferable to use them in combination. The undercoat layer can contain various commonly used additives. As additives, for example, preservatives, surfactants, hardeners, optical brighteners, pH stabilizers and the like can be used in appropriate combination.

  As a method of providing the undercoat layer on the resin layer side on which the receiving layer is provided, the undercoat layer is applied to the resin layer side on which the receiving layer is provided after the traveling base paper surface is coated and before winding. It is preferable to use a so-called on-machine method in which a coating liquid is applied and dried to provide an undercoat layer. Moreover, after winding up a resin-coated paper, after storing winding as needed, it can also carry out by what is called an off-machine method which provides an undercoat layer anew. Examples of apparatuses for applying the undercoating liquid include air knife coaters, roll coaters, bar coaters, wire bar coaters, blade coaters, slide hopper coaters, curtain coaters, gravure coaters, flexographic gravure coaters, and combinations thereof. Prior to the coating of the undercoat layer, other activation treatments such as flame treatment may be applied in addition to the corona discharge treatment of the resin surface. Various drying devices such as straight tunnel dryers, hot air dryers such as arch dryers, air loop dryers, sine curve air float dryers, dryers using infrared rays, heating dryers, microwaves, etc. Can give. Moreover, although drying conditions are arbitrary, generally it is performed at 40 to 150 degreeC for several seconds to 10 minutes.

A heat insulating / cushion layer may be provided on the surface of the support of the present invention opposite to the side on which the backcoat layer is provided in order to more efficiently utilize the thermal energy during printer printing. The heat insulation / cushion layer is not particularly limited as long as it has voids in the layer, but a void initiator (inorganic fine particles, organic fine particles, etc.) is added to the thermoplastic resin and biaxially stretched in the film. A porous film having voids is preferred. From the viewpoint of cost, productivity, etc., a polypropylene-based or polyethylene terephthalate-based biaxially stretched porous film is particularly preferable.
These biaxially stretched porous films are adhered to the surface opposite to the side of the support of the present invention on which the backcoat layer is provided by a known method such as dry lamination, wet lamination, or melt lamination. Can do. In addition, the heat insulation / cushion layer is formed by dispersing fine particles having a hollow inside in a binder resin and is opposite to the side on which the back coat layer of the support of the present invention is provided by a known coating method such as gravure coating, roll coating, die coating, etc. It may be provided on the side surface.

  The thickness of the heat insulating / cushion layer is preferably 30 to 75 μm. If the thickness is less than 30 μm, the heat insulation and cushioning properties are insufficient, resulting in a decrease in density during printing, uneven printing, and the like, which is not preferable in terms of printing quality. Moreover, when thickness exceeds 75 micrometers, cost increase and productivity will fall and it is unpreferable.

  On the support of the present invention or on the heat-insulating / cushion layer provided on the support, a receiving layer having a dyeing property for a dye which melts or sublimates due to heat and migrates is provided to constitute a thermal transfer receiving sheet However, an anchor layer may be provided between the receptor layer and the support of the present invention or between the heat insulating / cushion layer provided on the support to adjust adhesion and whiteness. As the dye-binding binder resin constituting the receptor layer, any resin can be suitably used as long as it has a strong interaction with the dye and can be stably diffused into the resin. For example, those having ester bonds include polyester resins, polyacrylate resins, polycarbonate resins, polyvinyl acetate resins, styrene acrylate resins, etc .; those having urethane bonds are polyurethane resins; those having amide bonds For example, a polyamide resin (nylon); a urea resin having a urea bond; a polycaprolactone resin, a polystyrene resin, a polyvinyl chloride, a polyacrylonitrile resin, etc. Can be used, or can be used as a copolymer having as a main component one or more of the structural units of the resin, for example, vinyl chloride-vinyl acetate copolymer, styrene-butadiene copolymer, etc. Furthermore, the above resins are used alone or in combination of two or more. Door can be. The above resin can be dissolved in water or an organic solvent and coated on the intermediate layer, or emulsified in an aqueous solution and coated as an emulsion.

  Further, a release agent may be added to the receiving layer for the purpose of preventing heat fusion with the ink donor sheet during printing. Specific examples of such release agents include higher fatty acids or esters thereof, amides or metal salts thereof, waxes such as shellac wax, montan wax, carnauba wax, polyethylene wax, and Teflon powders; Surfactant; Examples include silicone oil. Moreover, modified silicone oils such as amino-modified silicone, epoxy-modified silicone, alkyd-modified silicone, and polyester-modified silicone are also used as the silicone oil. As the silicone compound, a curable silicone compound can also be used if necessary. Examples of the curable silicone compound include a reaction curable type, an ionizing radiation curable type, and a catalyst curable type.

  Furthermore, additives such as dyes, pigments, wetting agents, antifoaming agents, dispersants, antistatic agents, fluorescent whitening agents, ultraviolet absorbers and light stabilizers can be contained in the receiving layer as necessary. . In particular, regarding the pigment, inorganic particles typified by silica, alumina, titanium oxide, calcium carbonate, kaolin, clay, zinc oxide, barium sulfate and the like can be added.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. In addition, unless otherwise indicated, all the parts and% in an Example show a mass part and mass%.

Examples 1-5 and Comparative Examples 1-5
A 1: 1 mixture of hardwood bleached kraft pulp (LBKP) and softwood bleached sulfite pulp (NBSP) was beaten to 300 ml with Canadian Standard Freeness to prepare a pulp slurry. To this, 5% of pigment having a ratio of light calcium carbonate / heavy calcium carbonate / talc of 30/35/35, alkyl ketene dimer as a sizing agent to 0.5% of pulp, and polyacrylamide as a strength agent to pulp. 0%, 2.0% cationized starch to pulp, 0.5% polyamide epichlorohydrin resin to pulp, diluted with water, and then adjusted to a basis weight of 170 g / m ² using a long net paper machine And dried to adjust the humidity to obtain a base paper for a thermal transfer support having a thickness of 155 μm.

Next, a polyethylene resin composition in which 10% anatase-type titanium is uniformly dispersed at 320 ° C. with respect to 100% by mass of low-density polyethylene having a density of 0.918 g / cm ^{3 on} the surface of the base paper produced. It was melted, extrusion coated to a thickness of 15 μm at 200 m / min, and extrusion coated using a cooling roll with a finely roughened surface. On the other side which is the back surface, a blend resin composition of 70 parts of a high density polyethylene resin having a density of 0.962 g / cm ³ and 30 parts of a low density polyethylene resin having a density of 0.918 was similarly melted at 320 ° C. The film was extrusion-coated to a thickness of 30 μm and extrusion-coated using a cooling roll having a rough surface.

Further, after the front and back resin layers were processed and wound up, the back resin layer surface was subjected to a corona discharge treatment, and then the aqueous coating liquid for back coat layer described in Table 1 was applied on-machine. The coating was applied at a coating amount of 0.5 g / m ² as a dry weight, and used as a support for thermal transfer. At this time, the glass transition temperature of the acrylic resin used in the coating liquid for the back coat layer is 30 ° C., and the spherical pigment has an average particle size of 4.0 μm (manufactured by Sekisui Plastics: MB -4C) was used.

  The evaluation method of the thermal transfer support obtained as described above was evaluated by the method described below.

[Evaluation method of brilliance]
The coating amount after drying the anchor layer coating solution and the receiving layer coating solution shown below on the resin layer surface on which the receiving layer of the support for thermal transfer obtained above is provided is 2.0 g / m ² and 5.0 g / m, respectively. A porous polypropylene film having a thickness of 39 μm coated with a gravure coater so as to be ² was bonded by a dry laminating method (coating amount after drying of adhesive 4.0 g / m ² ) to prepare a thermal transfer receiving sheet. This thermal transfer receiving sheet was allowed to stand for 2 days under the condition of 23 ° C./50% RH, and then 20 black solid patterns were continuously printed with a sublimation thermal transfer printer CP9000 manufactured by Mitsubishi Electric, and between the thermal transfer receiving sheets after printing. The relative degree of blocking was evaluated.
(Double-circle): The burrability is very good.
○: Good sag.
Δ: Slightly inferior, but no problem in practical use.
X: Poor property is inferior and there is a problem in practical use.
[Preparation of anchor layer coating solution]
Polyester resin (Polyester WR-905: Nippon Synthetic Chemical Industry) 50 parts Titanium oxide (TCA888: Tochem Products) 20 parts Optical brightener (Ubitex BAC: Ciba Specialty Chemicals) 1.2 parts Water / Isopropyl alcohol = 1/1 28.8 parts [Preparation of receiving layer coating solution]
Vinyl chloride-vinyl acetate copolymer resin (Solvine C: Nissin Chemical Industry) 20 parts Epoxy-modified silicone (X-22-3000T: Shin-Etsu Chemical Co., Ltd.) 2 parts Toluene / Methyl ethyl ketone = 1/78 parts [Adhesive coating solution Adjustment of]
Urethane resin (Takelac A-969V: Mitsui / Takeda Chemical) 30 parts Isocyanate (Takenate A-5: Mitsui / Takeda Chemical) 10 parts Ethyl acetate 60 parts

[Evaluation method of glue adhesion]
After coating the back coat surface of the thermal transfer support with an Arabic Yamato glue (manufactured by Yamato Co., Ltd .: NA-200) of about 2 cm wide × 10 cm long, and bonding PPC paper thereon and drying it sufficiently, Glue adhesion was evaluated by the degree of sticking of the PPC paper to the back coat layer when the PPC paper was slowly peeled off.
A: PPC paper is crushed and adhesiveness is very good.
○: PPC paper is partially crushed and adhesiveness is good.
Δ: Although not crushed, there is sufficient resistance to peeling, and there is no practical problem in adhesiveness.
X: It peels easily and has a problem in practical use.

  The obtained results are shown in Table 1.

  As is apparent from Table 1, it can be seen that the thermal transfer support of the present invention provides a thermal transfer receiving sheet that is excellent in the squeezing property between the thermal transfer receiving sheets after printing and the adhesiveness of the backcoat layer. When the copolymerization ratio (% by mass) of the acrylic resin in the silicone-modified water-based acrylic urethane copolymer resin is more than 50% by mass, the adhesiveness of the glue becomes a problem, and when it is less than 20% by mass, the tearability becomes a problem. Further, when the addition amount of the spherical pigment is less than 20% and when it is more than 40%, there is a problem in the sprinkling property.

Examples 6-9
The same procedure as in Example 3 was performed except that the glass transition temperature of the acrylic resin in the silicone-modified water-based acrylic urethane copolymer resin was as described in Table 2.

  The obtained results are shown in Table 2.

  As is clear from Table 2, the thermal transfer support of the present invention in which the glass transition temperature of the acrylic resin in the silicone-modified water-based acrylic urethane copolymer resin is 30 ° C. or higher is the repellency between the thermal transfer receiving sheets after printing. It can be seen that there is provided a thermal transfer receiving sheet excellent in adhesiveness of the backcoat layer. It can be seen that when the glass transition temperature is increased, the heat resistance is improved, and in particular, the tearability is improved.

Examples 10-15
The same operation as in Example 6 was conducted except that the average particle diameter of the spherical pigment was changed to those shown in Table 3.

  The obtained results are shown in Table 3.

  As is apparent from Table 3, the support for thermal transfer of the present invention in which the average particle diameter of the spherical pigment is in the range of 0.5 to 3.0 μm is the sagability of the receiving sheet for thermal transfer after printing and the backcoat layer. It can be seen that a thermal transfer receiving sheet having excellent adhesiveness is provided. It can be seen that as the average particle size becomes smaller, the adhesiveness of the glue is improved.

Examples 16-20
The support is a double-sided resin-coated paper, and a single-sided resin-coated paper having a base paper thickness of 170 μm and a reverse-side resin coating process (the thickness of the backside resin layer is 30 μm) opposite to the receiving layer. The same procedure as in Example 3 was performed except that it was used. Similarly, Example 17 was performed in the same manner as Example 6 and Examples 18, 19, and 20 were performed in the same manner as Examples 10, 12, and 15 except that single-sided resin-coated paper was used from double-sided resin-coated paper. It was.

Table 4 shows the obtained results.

  As apparent from Table 4, the thermal transfer receiving sheet using the single-sided resin-coated paper of the present invention as a support is similar to the thermal transfer receiving sheet using the double-sided resin-coated paper as a support. It can be seen that this is a thermal transfer receiving sheet excellent in spreading properties and adhesiveness of the back coat layer.

  According to the present invention, in a thermal transfer support, an environment-friendly resin-coated thermal transfer support centering on natural pulp, which has excellent spreadability between receiving sheets for thermal transfer after printer printing and adhesive adhesion of a backcoat layer Can provide a body.

Claims (4)

  In a thermal transfer support in which paper having natural pulp as a main component is used as a substrate and at least the surface opposite to the surface on which the substrate receiving layer is provided is coated with a resin layer containing a film-forming resin, the receiving layer is provided. A back coat layer is provided on the surface opposite to the surface, and the back coat layer is made of a silicone-modified water-based acrylic urethane copolymer resin, and the copolymer ratio (% by mass) of the acrylic resin and the urethane resin in this copolymer resin. ) Is 50:50 to 20:80, and a spherical pigment is contained in an amount of 20 to 40% by mass with respect to the total amount of resin contained in the backcoat layer. .   The support for thermal transfer according to claim 1, wherein the glass transition temperature of the acrylic resin contained in the backcoat layer is 30 ° C or higher.   The thermal transfer support according to claim 1 or 2, wherein the spherical pigment contained in the backcoat layer has an average particle size of 0.5 to 3.0 µm.   A thermal transfer receiving sheet, wherein at least a receiving layer is formed on the thermal transfer support according to claim 1.