JP2009000812A - Thermal transfer receiving sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal transfer receptive sheet which can obtain a clear image, which has improved durability, and which is usable for photographic purpose etc. <P>SOLUTION: Regarding the thermal transfer receptive sheet in which a barrier layer and an image receptive layer are sequentially laminated on at least one side of a sheet-like support, the barrier layer is formed by using water barrier-layer coating liquid containing water-soluble high polymer compound and aqueous active silica solution. Preferably, the aqueous active silica solution is created by performing dealkylation metal processing of the silicic acid alkali metal salt solution by ion exchanger. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The thermal transfer receiving sheet of the present invention relates to a thermal transfer receiving sheet that has a clear image and excellent durability and can be used for photographic applications.

  In the dye thermal transfer system, a thermal dye receiving sheet (hereinafter simply referred to as “ink ribbon”) having a dye layer and a thermal transfer receiving sheet (hereinafter simply referred to as “receiving layer”) for receiving the dye. Hereinafter, the dye layer and the receiving layer are overlapped using a “receiving sheet”), and the dye is transferred onto the receiving layer by heating to form an image. Heating is performed with a thermal head, and a full-color image is formed with multicolored dots. Since the dye is used, the image is clear and highly transparent, and a high-quality image usable for photographic use is obtained.

As the resin for forming the receiving layer, various thermoplastic resins having good dye dyeing properties have been proposed. For example, a vinyl chloride resin, a polyester resin, a polyvinyl acetal resin, an acrylic resin, a cellulose resin, and the like are disclosed (for example, see Patent Documents 1-3). A technique for preparing a receiving sheet by dissolving the thermoplastic resin in an organic solvent such as toluene or methyl ethyl ketone to prepare a receiving layer coating solution, and applying and drying the coating on a sheet-like support is shown. Yes. In addition, various proposals have been made for dyeable resins for receiving layers of water-soluble or water-dispersible resins because they have little influence on the environment. For example, aqueous dispersions of polyester resins are disclosed ( For example, see Patent Document 4.)
However, the conventional receiving sheet is insufficient in preventing bleeding of a recorded image particularly when stored in a high temperature and high humidity environment.

  In order to improve image bleeding, it has been proposed to provide a barrier layer containing a water-soluble polymer compound between the support and the receiving layer. For example, a barrier layer made of a mixture of polyvinyl alcohol and polyurethane resin is disclosed. (For example, refer to Patent Document 5). However, since the proposed barrier layer is inferior in water resistance, when a water-based receiving layer is provided on the barrier layer, the barrier layer is dissolved and mixed with the receiving layer coating solution. Decreases the glossiness and smoothness of the receiving layer surface. Furthermore, since the barrier layer resin is mixed in the receiving layer, the dyeing property is lowered, and the image is low in density when printed, and the image becomes unclear.

  Moreover, the barrier layer which has aqueous resin and a hardening | curing agent as a main component is disclosed as a water resistant barrier layer (for example, refer patent document 6). However, the coating liquid for the barrier layer is likely to be gelled or aggregated with time due to the curing agent, and the so-called coating liquid pot life is shortened.

Furthermore, the barrier layer which consists of a radiation curable resin composition is disclosed (for example, refer patent document 7). However, the resin of the barrier layer is limited to those having radiation curability, which is not sufficient for preventing the diffusion of the dye, and the blur of the image is unsatisfactory. In addition, special equipment is required for curing, which is disadvantageous in terms of cost.
In addition, a proposal has been made that a hydrophobic layer is provided by offset printing or gravure printing of a solvent-based resin to form a barrier layer (see, for example, Patent Document 8). However, offset ink and gravure ink have high affinity with dye, and this hydrophobic layer is insufficient in preventing diffusion of the dye.

JP 59-224844 (first page) JP 61-199997 A (first page) Japanese Unexamined Patent Publication No. 3-65391 (first page) JP-A-6-234269 (2nd page) JP 11-34515 A (2nd page) JP 2002-278456 A (page 2) JP-A-8-34169 (2nd page) Japanese Patent Laid-Open No. 1-166991 (page 1-2)

  The receiving sheet of the present invention is to provide a receiving sheet that has a clear image and excellent durability and can be used for photographic use.

  As a result of earnest research to solve the above-mentioned problems, in the receiving sheet in which the barrier layer and the receiving layer are sequentially laminated, the coating liquid of the barrier layer containing the water-soluble polymer compound contains active silicic acid. The present inventors have found that a receiving sheet having no image blur and a high printing density can be obtained, and the present invention has been achieved. The present invention includes the following inventions.

(1) In a thermal transfer receiving sheet in which a barrier layer and an image receiving layer are sequentially laminated on at least one surface on a sheet-like support, the barrier layer includes a water-soluble polymer compound and an active silicic acid aqueous solution. A thermal transfer receiving sheet formed by using a liquid.
(2) The thermal transfer receiving sheet according to item (1), wherein the active silicic acid aqueous solution is an active silicic acid aqueous solution produced by subjecting an alkali metal silicate aqueous solution to a dealkalizing metal treatment with an ion exchanger.
(3) The thermal transfer receiving sheet according to item (2), wherein the ion exchanger is a hydrogen type cation exchange resin.
(4) The thermal transfer receiving sheet according to item (2), wherein the alkali metal silicate aqueous solution is at least one selected from a sodium silicate aqueous solution, a potassium silicate aqueous solution and a lithium silicate aqueous solution.

(5) The thermal transfer receiving sheet according to any one of (1) to (4), wherein the active silicic acid aqueous solution is an active silicic acid aqueous solution adjusted to pH 2 to 12.
(6) The sheet-like support is a paper base material mainly composed of cellulose pulp, and further an intermediate layer containing hollow particles is provided between the paper base material and the barrier layer. 5. The thermal transfer receiving sheet according to any one of items 5).
(7) The thermal transfer receiving sheet according to any one of (1) to (6), wherein the water-soluble polymer compound is a polyvinyl alcohol resin.

(8) The thermal transfer receiving sheet according to any one of (1) to (7), wherein the barrier layer coating solution further contains a swellable inorganic layered compound.
(9) In any one of the items (1) to (8), the solid content of the active silicic acid is 0.3 to 35% by mass with respect to the total solid content of the coating liquid for the barrier layer. The thermal transfer receiving sheet described.
(10) The thermal transfer receiving sheet according to any one of items (1) to (9), wherein the image receiving layer is formed using an aqueous coating liquid mainly composed of a thermoplastic resin.

  The receiving sheet of the present invention is a receiving sheet that has a clear image, does not bleed even in a high-humidity environment, has good fingerprint resistance, has excellent image durability, and can be used for photographic applications.

  The receiving sheet of the present invention has a configuration in which a barrier layer containing a water-soluble polymer compound, a receiving layer and the like are sequentially laminated on at least one surface of a sheet-like support. Hereinafter, the present invention will be described in more detail.

(Barrier layer)
The barrier layer containing the water-soluble polymer compound can prevent bleeding of the image by preventing the dye dyed on the receiving layer from moving to the intermediate layer or the support. As the water-soluble polymer compound used for the barrier layer, a resin having excellent film forming ability, elasticity and flexibility is used.

  Specific examples of the water-soluble polymer compound are given. Examples of starches include oxidized starch, phosphate esterified starch, acetylated starch, etherified starch, cationized starch, carbamate starch, hydroxymethylated starch, hydroxyethylated starch, and hydroxypropylated starch. Examples of the polyvinyl alcohol-based resin include fully saponified polyvinyl alcohol (saponification degree 97 to 100%), partially saponified polyvinyl alcohol (saponification degree 73 to less than 97%), functional group-modified polyvinyl alcohol, etc. Carboxyl group, carbonyl group, epoxy group, amino group, amine group, thiol group, sulfonic acid group, phosphoric acid group, silanol group, etc.) and copolymers of vinyl alcohol and other polymerizable monomers (for example, ethylene vinyl alcohol) Copolymer) and the like. Examples of celluloses include methoxycellulose, carboxymethylcellulose, methylcellulose, and ethylcellulose.

  Other polymer materials include polyester, polyurethane, polyacrylic acid soda, polyvinylpyrrolidone, acrylic acid amide / acrylic acid ester copolymer, acrylic acid amide / acrylic acid ester / methacrylic acid terpolymer, styrene / anhydrous Maleic acid copolymer alkali metal salts, polyacrylamide, sodium alginate, gelatin, casein and the like can be mentioned.

  Among the water-soluble polymer compounds described above, the polyvinyl alcohol-based resin is preferably used in terms of good heat resistance, substrate adhesion, and flexibility. The receiving sheet containing the polyvinyl alcohol-based resin in the barrier layer is stable without being softened even when heated during printing. In addition, the adhesiveness to the support is excellent, and problems such as peeling of the coating layer hardly occur. Further, even if the receiving sheet is bent, the receiving sheet is hardly cracked. In addition, flexibility refers to difficulty in folding and flexibility when bent, and is defined in, for example, JIS A 6909.

  The polymerization degree of polyvinyl alcohols is preferably 200 to 2000. If the degree of polymerization is less than 200, the strength of the film to be formed is weak and the dye barrier property may be insufficient. If the degree of polymerization exceeds 2000, the viscosity of an aqueous solution may increase and handling may be difficult. As such polyvinyl alcohols, commercially available products can be preferably used, and examples thereof include PVA102, 103, 105, 117, 120 (above, manufactured by Kuraray, fully saponified polyvinyl alcohol), PVA617, 203, Examples thereof include 205, 210, 217, 220, 403, 405, and 420 (manufactured by Kuraray, partially saponified polyvinyl alcohol) having different degrees of polymerization and saponification.

  Further, modified polyvinyl alcohols such as silanol-modified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, and mercapto group-containing polyvinyl alcohol can also be used. Examples of such various modified polyvinyl alcohols include R-1130, R-2105, R-2130 (above, made by Kuraray, silanol-modified polyvinyl alcohol), KL-506, KL-318 (above, made by Kuraray, carboxy-modified polyvinyl alcohol). Alcohol), Z-200, 210, 320 (above, Nippon Synthetic Chemical Co., Ltd., acetoacetyl-modified polyvinyl alcohol), C-506, CM-318 (above, Kuraray, cation-modified polyvinyl alcohol), M-115, M- 205 (manufactured by Kuraray Co., Ltd., mercapto group-containing polyvinyl alcohol) is commercially available.

  The ethylene vinyl alcohol copolymer exhibits excellent water resistance even at a low degree of polymerization, and the aqueous solution has an extremely low viscosity and is suitable for thin film forming coating. Tg is usually 0 ° C. or lower. Specific examples include Kuraray's product names “RS4103”, “RS4105”, “RS2117”, “HR3010”, and the like.

  Among the polyvinyl alcohol resins, fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, ethylene vinyl alcohol copolymer, and the like are preferably used, and are excellent in dye barrier properties, flexibility, coating suitability, and the like.

  The solid content ratio of the water-soluble polymer compound to the total solid content mass of the barrier layer is preferably 50 to 97% by mass. If the solid content ratio is less than 50% by mass, the dye barrier effect may be insufficient and the image may be blurred over time. If it exceeds 97% by mass, the water resistance is insufficient, and when the receiving layer coating solution is applied, the barrier layer dissolves and mixes with the receiving layer coating solution. In this case, even if the obtained receiving sheet is printed, the image may become unclear.

  The barrier layer coating solution of the present invention further needs to contain an active silicic acid aqueous solution. When a water-soluble polymer compound and active silicic acid are used in combination, the silanol group possessed by the active silicic acid reacts with a hydrophilic group possessed by the water-soluble polymer compound, such as a hydroxyl group or a carboxyl group, to form a strong hydrogen bond. It is considered that the formation of hydrogen bonds can impart high water resistance to the barrier layer.

  The active silicic acid aqueous solution used in the present invention is made from an alkali metal silicate aqueous solution. Since an active silicic acid aqueous solution not containing an organic solvent can be obtained by using an alkali metal silicate aqueous solution as a raw material, it is particularly important in making a paint aqueous. Although the alkali metal silicate aqueous solution used in the present invention is not particularly limited, sodium silicate aqueous solution, potassium silicate aqueous solution, and lithium silicate aqueous solution are preferable. From the viewpoint of cost, sodium silicate aqueous solution and lithium silicate aqueous solution are more preferable, sodium silicate aqueous solution is particularly preferable, and among them, No. 3 sodium silicate aqueous solution defined by JIS K 1408 is particularly preferable.

  In the present invention, an active silicic acid aqueous solution is prepared by subjecting an alkali metal silicate aqueous solution to dealkalizing metal treatment with an ion exchanger. In the present invention, the reason for using the active silicic acid aqueous solution obtained by subjecting the alkali metal silicate aqueous solution to dealkalizing metal treatment with an ion exchanger is because it can be completely water-based as described above.

  Any ion exchanger can be used, but a cation inorganic ion exchanger or a hydrogen type cation exchange resin can be preferably used, and a hydrogen type cation exchange resin is particularly preferable. Any hydrogen-type cation exchange resin can be used.

  The concentration of the alkali metal silicate aqueous solution is preferably 0.5 to 15% by mass, more preferably 1 to 10% by mass, and further preferably 2 to 7% by mass. If the concentration of the alkali metal silicate aqueous solution is too high, the dealkalizing metal treatment with the ion exchanger may not be performed sufficiently. When the concentration of the alkali metal silicate aqueous solution is too low, the active silicic acid aqueous solution after the dealkalizing metal treatment is low, and the concentration of the barrier layer coating solution to which this is added may be too low.

  The concentration of the active silicic acid aqueous solution obtained by subjecting the alkali metal silicate aqueous solution to dealkalizing metal treatment with an ion exchanger is preferably 0.05 to 12% by mass, more preferably 0.5 to 7% by mass, and 1 to 6%. More preferred is mass%. If the concentration of the active silicic acid aqueous solution is in the range of 0.05 to 12% by mass, the pot life of the active silicic acid aqueous solution has no practical problem, and the concentration of the coating solution for the barrier layer containing the active silicic acid aqueous solution is also applied. Thus, it can be adjusted to a concentration having no practical problem.

  In addition, the obtained active silicic acid aqueous solution has a pH of about 3.5 or less, but after adding a basic aqueous solution such as aqueous ammonia and adjusting the pH, by preparing a barrier layer coating solution, Further improvement effects can be obtained with respect to the pot life of the coating liquid for the barrier layer. The active silicic acid aqueous solution of the present invention is preferably used at a pH of 2 to 12, more preferably 8 to 11. If the pH is less than 2, the pot life of the barrier layer coating solution may be too short. If the pH exceeds 12, the water resistance of the barrier layer may be insufficient.

  The temperature at which the active silicic acid aqueous solution is prepared from the alkali metal silicate aqueous solution by an ion exchanger is preferably 0 to 50 ° C, more preferably 10 to 40 ° C, further preferably 15 to 30 ° C. If it is a temperature range of 0-50 degreeC, a dealkalizing metal process will be performed smoothly and the thing of the level which does not have a problem practically will also be obtained for the pot life of the produced | generated active silicic acid aqueous solution.

  The solid content ratio of the active silicic acid used in the barrier layer coating solution is preferably 0.3 to 35% by mass, more preferably 1 to 25% by mass, based on the total solid content of the barrier layer coating solution. -20 mass% is further more preferable. If the solid content ratio is less than 0.3% by mass, sufficient water resistance may not be obtained for the barrier layer. In this case, the barrier layer dissolves and mixes with the receiving layer coating solution during coating of the receiving layer, and the resulting receiving sheet may have low gloss and smoothness, resulting in poor dye dyeability and an unclear image. . When the solid content ratio exceeds 35% by mass, the flexibility of the barrier layer is insufficient, and cracks may occur on the coated surface of the barrier layer when bent. In addition, there may be a problem in the stability of the coating solution such that the coating solution for the barrier layer tends to gel with time.

  Further, the barrier layer preferably further contains a swellable inorganic layered compound in order to prevent image bleeding. Examples of the swellable inorganic layered compounds include synthetic mica such as fluorine phlogopite, potassium tetrasilicon mica, sodium tetrasilicon mica, sodium teniolite and lithium teniolite, or synthetic smectite such as sodium hectorite, lithium hectorite and saponite. Can be mentioned.

  The aspect ratio of the swellable inorganic layered compound used in the present invention is preferably 10 to 5000. If the aspect ratio is less than 10, the prevention of bleeding due to the barrier effect may be insufficient. When it exceeds 5000, the layered compound becomes thin and the dispersibility may become unstable. The aspect ratio is the ratio of the short axis to the long axis of the layered compound. Since the inorganic layered compound usually has a flat shape, the shape can be approximated by a spheroid. The ratio of the minor axis to the major axis of this spheroid is called the aspect ratio. A high aspect ratio means that the layered compound is thinner and more in number. Since the sublimation dye passes between the layered compounds, the number of detours is further increased and the path is lengthened. Therefore, when the aspect ratio is high, the barrier property is high. The aspect ratio can be calculated by measuring the short axis and long axis of the layered compound with a laser particle size distribution meter or an electron microscope.

  In addition, the particle average major axis of the swellable inorganic layered compound used in the present invention is preferably in the range of 0.1 to 100 μm, and more preferably in the range of 2 to 20 μm. If the average particle major axis is less than 0.1 μm, the aspect ratio becomes small, and it becomes difficult to spread in parallel on the intermediate layer, so that image blurring may not be completely prevented. On the other hand, when the average particle major axis exceeds 100 μm, the swellable inorganic layered compound protrudes from the barrier layer, resulting in irregularities on the surface of the barrier layer, and the smoothness of the surface of the receiving layer is lowered to deteriorate the image quality. There are things to do.

  In the barrier layer, a water-soluble polymer compound and a water-dispersible resin can be used in combination as necessary. Specific examples of water-dispersible resins that can be used in combination include styrene-butadiene copolymer latex, acrylic ester resin latex, methacrylic ester copolymer latex, ethylene-vinyl acetate copolymer latex, and polyester emulsion. Polyester polyurethane ionomer, polyether polyurethane ionomer, and the like.

  Furthermore, various auxiliary agents such as lubricants, antifoaming agents, wetting agents, preservatives, fluorescent whitening agents, dispersing agents, thickeners, coloring agents, antistatic agents, etc. are added to the barrier layer. Can be used.

The solid content coating amount of the barrier layer is preferably 0.3 to 5.0 g / m ² . When the solid content coating amount is less than 0.3 g / m ² , the effect of preventing the movement of the dye is poor, and image bleeding may occur over time. If it exceeds 5.0 g / m ² , the flexibility of the coating layer is lowered and cracks are likely to occur when it is bent, and the dye may pass through the cracks and diffuse to the support, causing blemishes and the like. is there.

(Receptive layer)
As the resin for forming the receiving layer, a thermoplastic resin having high affinity for dyes and good dye dyeing properties is used. Such resins include polyester resins, polyurethane resins, polycarbonate resins, polyvinyl chloride resins, vinyl chloride-vinyl acetate copolymer resins, vinyl chloride-acrylic copolymer resins, polyvinyl acetal resins, polyvinyl butyral resins, polystyrene resins. And thermoplastic resins such as polyacrylate resin, cellulose resin, and polyamide resin. These thermoplastic resins may be used alone or in combination of two or more.
Among these, polyester resins excellent in dye dyeing property, and vinyl chloride copolymer resins such as vinyl chloride-vinyl acetate copolymer resins and vinyl chloride-acrylic copolymer resins are preferably used.

The polyester resin used in the present invention is synthesized by polycondensation of a polyvalent carboxylic acid component and a polyhydric alcohol component. A polyester resin having a branched structure is particularly preferable from the viewpoint of heat resistance.
The polyester resin preferably contains 50 mol% or more of an isophthalic acid component in the polyvalent carboxylic acid component. If it is less than 50 mol%, the light resistance of the resulting polyester resin may be lowered. In the polyvalent carboxylic acid component, it is possible to use an aromatic dicarboxylic acid other than alicyclic dicarboxylic acid, aliphatic dicarboxylic acid, and isophthalic acid. In order to increase the glass transition temperature of the polyester resin or to form a branched structure, a trivalent or higher carboxylic acid can be contained as a polyvalent carboxylic acid component.

  The polyester resin preferably uses alicyclic glycols and / or aliphatic glycols as the polyhydric alcohol component. These may be used alone or in combination of two or more. It is also possible to carry out polycondensation by adding a trihydric or higher polyhydric alcohol.

  Examples of the vinyl chloride copolymer used in the present invention include copolymers of vinyl chloride and other comonomers containing vinyl chloride as a monomer unit in a proportion of 50% by mass or more. Among them, a copolymer of vinyl chloride and vinyl acetate and a copolymer of vinyl chloride and acrylic are particularly preferable because of their good affinity with dyes. As the vinyl chloride copolymer resin, those having a hydroxyl group or a carboxyl group introduced are preferably used.

  The polyester resin and vinyl chloride copolymer resin preferably have a glass transition temperature of 30 to 80 ° C, more preferably 40 to 70 ° C. When the glass transition temperature is less than 30 ° C., the heat resistance is insufficient, and the ink ribbon and the receiving layer may stick to each other during printing. If it exceeds 80 ° C., the dyeing property is inferior and a clear image may not be formed. Glass transition refers to a phenomenon that changes from a glassy hard state to a rubbery state when a polymer substance is heated, and the rigidity and viscosity are lowered. The temperature at which the glass transition occurs is called the glass transition temperature. The glass transition temperature is obtained by measuring the endothermic amount when the test piece is heated at a constant speed with a differential scanning calorimeter (DSC), and is defined in JIS C 6481.

The polyester resin and vinyl chloride copolymer resin preferably have a number average molecular weight of 1,000 to 50,000. If the number average molecular weight is less than 1000, the formed film may be insufficient in flexibility and may be easily cracked. If it exceeds 50,000, the dyeing property may be insufficient and a clear image may not be obtained.
The number average molecular weight is an average molecular weight per molecule. A synthetic polymer is usually a mixture of molecules having different molecular weights, and the number average molecular weight is obtained by dividing the sum of the molecular weights by the number of molecules. For the molecular weight measurement, gel permeation chromatography (GPC) is used. A dilute solution of the test material is allowed to flow through a column packed with gel-like particles, and the time until it flows out is measured. The molecular weight can be calculated by utilizing the fact that the outflow time varies depending on the size of the molecule.

Although not particularly limited in the present invention, it is preferable that the coating solution for the receiving layer containing the thermoplastic resin as a main component is water-based, and an extremely excellent effect is exhibited by forming it on the barrier layer of the present application. The The thermoplastic resin used in the receiving layer may exist in a state dissolved in water, or may exist in a state dispersed in water. In order to make the thermoplastic resin water-soluble, there is a method of introducing a hydrophilic group into the polymer skeleton or the side chain. Examples of the hydrophilic group include a carboxyl group, a phosphate ester group, a sulfone group, an amino group, an imino group, a tertiary amine group, a hydroxyl group, an ether group, and an amide group. Generally, after introducing a hydrophilic group, neutralizing with a counter ion to form a hydrophilic soap or ionic group and dissolving it in water. In the case of water dispersion, a known technique such as an emulsion polymerization method can be used. Receiving layer coating weight, 1 to 10 g / ^{m 2} is preferred. If it is less than 1 g / m ² , dye dyeing properties may not be sufficiently obtained. On the other hand, if it exceeds 10 g / m ² , the effect obtained for an increase in cost is small.

  It is preferable to add a crosslinking agent to the receiving layer in order to improve heat resistance. Examples of the crosslinking agent include polyisocyanate compounds, epoxy compounds, oxazoline compounds, carbodiimide compounds, organometallic compounds, and the like. The cross-linking agent can react with the functional group of the thermoplastic resin to cross-link three-dimensionally. Examples of the functional group include a hydroxyl group, an amino group, a carboxyl group, and an epoxy group.

  In addition, a release agent is preferably added to the receiving layer for the purpose of improving the peelability from the ink ribbon during printing. Examples of the mold release agent include silicone oils, silicone compounds such as silicone resins, various waxes such as polyethylene wax, and metal soaps. Further, for the purpose of improving the image storage stability, an antioxidant, an ultraviolet absorber and the like can be added to the receiving layer.

(Sheet support)
As the support for the receiving sheet used in the present invention, papers and synthetic resin sheets mainly composed of cellulose pulp are used. Examples of paper include high-quality paper (acidic paper, neutral paper), medium-quality paper, coated paper, art paper, glassine paper, and resin-laminated paper. Examples of the sheet mainly composed of a synthetic resin include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, polyamides, polyvinyl chloride, polystyrene, polycarbonate, and polyvinyl chloride. Examples of the porous stretched sheets include, for example, synthetic paper, porous polyester sheet and the like mainly composed of a thermoplastic resin such as polyolefin and polyester.

  The above-mentioned sheets may be used alone, or may be a laminate sheet obtained by laminating and adhering porous stretched sheets, porous stretched sheets and other sheets and / or papers. In addition, the sheet-like support used in the present invention may have a structure in which a first base material layer on which a receptor layer is formed, an adhesive layer, a release agent layer, and a second base material layer are sequentially laminated, Of course, a sheet-like support having a so-called label type (also called a sticker or seal type) structure can be used.

  The smoothness on the receiving layer surface side of the sheet-like support is preferably 50 seconds or more. If it is less than 50 seconds, the smoothness of the obtained receiving sheet may be insufficient, and the image uniformity may be impaired. The smoothness is an index of the smoothness of the sheet surface. Obtained by measuring the flow rate of air flowing between the reference surface and the surface of the specimen under a certain condition. TAPPI paper pulp test method no. 5 (Oken smoothness).

In the present invention, among the above sheet-like supports, papers mainly composed of cellulose pulp are preferable. The texture of the receiving sheet obtained is close to that of photographic paper, which is advantageous in terms of cost.
(Middle layer)

  In the case of using a paper support, it is preferable to provide an intermediate layer containing hollow particles on the support. Since the intermediate layer containing hollow particles can impart heat insulation and cushioning properties, it can improve image clarity and image uniformity. The material and manufacturing method of the hollow particles used in the intermediate layer are not particularly limited, and specific examples of the material for forming the walls of the hollow particles include acrylonitrile, vinylidene chloride, styrene acrylate polymer, and the like. . As a method for producing these hollow particles, a method of heating and foaming microcapsules in which butane gas is sealed in resin particles, an emulsion polymerization method, and the like can be mentioned.

The coating amount of the intermediate layer, 1 to 30 g / ^{m 2} is preferred. If the coating amount of the intermediate layer is less than 1 g / m ² , sufficient heat insulating properties and cushioning properties cannot be expected, and if it exceeds 30 g / m ² , the effect obtained for the cost increases is small.

  The particle size of the hollow particles is preferably 0.1 to 10 μm. When the particle size of the hollow particles is less than 0.1 μm, the walls of the hollow particles become thin and the heat resistance is insufficient, and is easily broken in the coating and drying process. On the other hand, when the thickness exceeds 10 μm, surface irregularities of the obtained receiving sheet are increased and image uniformity may be deteriorated. The volume hollow ratio of the hollow particles is preferably 50 to 90%. When the volumetric hollow ratio of the hollow particles is less than 50%, the effect of imparting heat insulating properties and cushioning properties may be insufficient. If it exceeds 90%, the walls of the hollow particles become thin and the durability may be lowered.

(Back layer)
In the receiving sheet of the present invention, a back surface layer is appropriately provided on the surface (back surface) on which the receiving layer is not provided. The purpose of the back layer is to improve runnability, prevent static electricity, prevent scratching of the receiving layer due to friction between the receiving sheets, and prevent dye transfer to the back surface when the receiving sheets are stacked. The back layer contains a resin as an adhesive component and, if necessary, a pigment and an additive.

  In the present invention, in particular, when an intermediate layer containing hollow particles is provided on a sheet-like support, calendering may be appropriately performed at the time of preparing the receiving sheet. By the calendering process, the unevenness of the surface of the obtained receiving sheet can be reduced and a uniform image can be obtained. The calendar treatment may be performed at any stage after coating of the intermediate layer, the barrier layer, and the receiving layer. As the calendar device used for the calendar process, a calendar device generally used in the paper industry such as a super calendar, a soft calendar, a gloss calendar, a clearance calendar, or the like can be appropriately used.

The coating liquid for each coating layer includes various auxiliary agents such as wetting agents, dispersing agents, thickeners, antifoaming agents, colorants, antistatic agents, preservatives and the like used in general coated paper production. Is added as appropriate.
In the present invention, the barrier layer, the receiving layer, and other coating layers are a bar coater, a gravure coater, a comma coater, a blade coater, an air knife coater, a gate roll coater, a die coater, a curtain coater, and a slide bead coater. Using a known coater, a predetermined coating solution can be applied and dried.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. Further, “parts” and “%” in the examples represent “parts by mass” and “mass%”, respectively, and are solid amounts unless otherwise specified.

Example 1
(Preparation of sheet-like support A)
A multilayer film of polypropylene (trade name: YUPO FPG50, manufactured by YUPO Corporation) was laminated on both sides of high-quality paper having a thickness of 100 μm by a dry lamination method to obtain a sheet-like support A.

(Preparation of active silicic acid aqueous solution A)
Water was mixed with a sodium silicate aqueous solution (trade name: No. 3 sodium silicate, manufactured by Toso Sangyo Co., Ltd.) having a SiO ₂ concentration of 30% by mass and a SiO ₂ / Na ₂ O molar ratio of 3.1, and adjusted to 25 ° C. Later, it was passed through a column packed with a strongly acidic hydrogen type cation exchange resin (trade name: Diaion SK-1BH, manufactured by Mitsubishi Chemical Corporation) to carry out dealkalizing metal treatment to obtain an active silicic acid aqueous solution. The obtained active silicic acid aqueous solution was adjusted with aqueous ammonia to obtain an active silicic acid aqueous solution A. The obtained active silicic acid aqueous solution A had a solid content concentration of 5.0% by mass and a pH of 9.0.

Preparation of coating solution A for barrier layer Polyvinyl alcohol aqueous solution (trade name: PVA117, manufactured by Kuraray,
Polymerization degree 1700, saponification degree 99 mol%, solid content 10%) 90 parts Active silicic acid aqueous solution A 10 parts Further, preparation water was added so that the solid content concentration would be 8% to prepare coating liquid A for barrier layer.

Preparation of receptor layer coating liquid A Polyester resin emulsion (trade name: PMD1200, manufactured by Toyobo,
Tg 67 ° C., molecular weight 15000, solid content 40%) 90 parts polyisocyanate (trade name: IS-70N, manufactured by Nikka Chemical Co., Ltd., 100% solid content) 10 parts Further, prepared water is added so that the solid content concentration becomes 20% A receiving layer coating solution A was prepared.

Using the barrier layer coating liquid A having the above composition, the sheet-like support A was coated and dried so that the solid content coating amount was 3 g / m ² to form a barrier layer. Next, on this barrier layer, the receiving layer coating liquid A was applied and dried so that the solid coating amount was 5 g / m ² , thereby obtaining a receiving sheet.

Example 2
In Example 1, a receiving sheet was obtained in the same manner as in Example 1 except that instead of the barrier layer coating liquid A, a barrier layer coating liquid B having the following composition was used.
(Preparation of active silicic acid aqueous solution B)
After adjusting water to a sodium silicate aqueous solution (trade name: No. 3 sodium silicate, manufactured by Toso Sangyo Co., Ltd.) having a SiO ₂ concentration of 30% by mass and a SiO ₂ / Na ₂ O molar ratio of 3.1 and adjusting to 25 ° C. Then, it was passed through a column packed with a strongly acidic hydrogen cation exchange resin (trade name: Diaion SK-1BH, manufactured by Mitsubishi Chemical Corporation), and treated with dealkalizing metal to obtain an active silicic acid aqueous solution B. The obtained active silicic acid aqueous solution B had a solid content concentration of 7.0% by mass and a pH of 2.5.

Preparation of barrier layer coating solution B Ethylene vinyl alcohol aqueous solution (trade name: RS4103, manufactured by Kuraray,
(Polymerization degree 300, solid content 15%) 70 parts Active silicic acid aqueous solution B 30 parts Furthermore, preparation water was added so that solid content concentration might be 10%, and the coating liquid B for barrier layers was prepared.

Example 3
In Example 1, instead of the barrier layer coating solution A, a barrier layer coating solution C having the following composition was used to form a barrier layer having a solid content coating amount of 5 g / m ² , and the receiving layer coating was further performed. A receiving sheet was obtained in the same manner as in Example 1 except that the receiving layer coating solution B having the following composition was used instead of the solution A.

(Preparation of active silicic acid aqueous solution C)
SiO ₂ concentration of 20 mass%, _SiO 2 / Li ₂ O molar ratio of 3.5 of lithium silicate solution (trade name: lithium silicate 35, Nippon Chemical Industrial Co., Ltd.) after adjusting the water were mixed 25 ° C., the strongly acidic An active silicic acid aqueous solution was obtained through dealkalizing metal treatment through a column packed with hydrogen-type cation exchange resin (trade name: Diaion SK-1BH, manufactured by Mitsubishi Chemical Corporation). The pH of the obtained active silicic acid aqueous solution was adjusted using aqueous ammonia to obtain an active silicic acid aqueous solution C. The obtained active silicic acid aqueous solution C had a solid content concentration of 4.9% by mass and a pH of 12.

Preparation of coating liquid C for barrier layer Polyvinyl alcohol aqueous solution (trade name: PVA403, manufactured by Kuraray,
Polymerization degree 300, saponification degree 80 mol%, solid content 20%) 60 parts swellable inorganic layered compound (sodium 4 silicon mica, particle average major axis 6.3 μm,
Aspect ratio 2700, solid content 5%) 20 parts active silicic acid aqueous solution C 20 parts Further, preparation water was added so that the solid content concentration would be 10% to prepare barrier layer coating solution C.

Preparation of receiving layer coating liquid B Vinyl chloride-vinyl acetate copolymer resin emulsion (trade name: VINYBRAN 603,
90 parts polyisocyanate (trade name: IS-70N, manufactured by Nikka Chemical Co., Ltd., manufactured by Nissin Chemical, Tg 64 ° C., solid content 50%)
(Solid content: 100%) 10 parts Further, preparation water was added so that the solid content concentration was 20% to prepare a receiving layer coating solution B.

Example 4
In Example 1, the barrier layer coating solution D having the following composition was used instead of the barrier layer coating solution A, and the receiving layer coating solution C having the following composition was used instead of the receiving layer coating solution A. Obtained a receiving sheet in the same manner as in Example 1.
(Preparation of active silicic acid aqueous solution D)
After mixing water in a potassium silicate aqueous solution (trade name: potassium potassium silicate, manufactured by Nippon Chemical Industry Co., Ltd.) having a SiO ₂ concentration of 29 mass% and a SiO ₂ / Li ₂ O molar ratio of 2.6, the mixture was adjusted to 25 ° C. and then strongly acidic. An active silicic acid aqueous solution was obtained through dealkalizing metal treatment through a column packed with a hydrogen-type cation exchange resin (trade name: Diaion SK-1BH, manufactured by Mitsubishi Chemical Corporation). Adjusting pH using a sodium silicate aqueous solution (trade name: No. 3 sodium silicate, manufactured by Toso Sangyo Co., Ltd.) having a SiO ₂ concentration of 30% by mass and a SiO ₂ / Na ₂ O molar ratio of 3.1, an active silicic acid aqueous solution D was obtained. The obtained active silicic acid aqueous solution D had a solid content concentration of 0.5% by mass and a pH of 7.5.

Preparation of coating solution D for barrier layer Water-soluble acrylic resin (trade name: SA513, manufactured by Chuo Rika,
Tg 60 ° C., solid content 29%) 99.5 parts Active silicic acid aqueous solution D 0.5 parts Further, preparation water was added so that the solid content concentration would be 10% to prepare coating solution D for barrier layer.

Receiving layer coating solution C of Preparation <br/> water-soluble polyester resin (trade name: Sukaibon EW312,
90 parts polyisocyanate (trade name: IS-70N, manufactured by Nikka Chemical Co., Ltd., manufactured by SK Chemicals, Tg 64 ° C., solid content 20%)
(Solid content: 100%) Preparation water was added so that the solid content concentration was further 20 parts by 10 parts, and the receiving layer coating C was prepared.

Example 5
In Example 1, instead of the sheet-like support A, a sheet-like support B on which the following intermediate layer was formed was used, and instead of the barrier layer coating liquid A, a barrier layer coating liquid E having the following composition was used. A receiving sheet was obtained in the same manner as in Example 1 except that the barrier layer coating amount was 0.3 g / m ² .
(Intermediate layer formation)
As a sheet-like support, art paper having a thickness of 150 μm (trade name: OK Kanto N, manufactured by Oji Paper Co., Ltd., basis weight 174.4 g / m ² ) is used, and an intermediate layer coating solution A having the following composition is provided on one side thereof. , coated so that the solid coating amount becomes 10 g / m ^2, and dried to form an intermediate layer, to obtain a sheet-like support B.

Preparation of intermediate layer coating liquid A Styrene acrylic hollow particle emulsion (trade name: Nipol MH5055,
Made by Nippon Zeon, 30% aqueous dispersion,
70 parts polyvinyl alcohol aqueous solution (trade name: PVA205, manufactured by Kuraray Co., Ltd.)
10% styrene-butadiene latex (trade name: PT1004, manufactured by Nippon Zeon,
45% aqueous dispersion) 20 parts of the mixture was further added with prepared water so that the solid content concentration was 30% to prepare an intermediate layer coating solution A.

Preparation of the barrier layer coating solution E <br/> styrene-acrylic copolymer resin (trade name: Polymaron 326, Arakawa Chemical Co.,
Tg 50 ° C., solid content concentration 20.7%) 80 parts active silicic acid aqueous solution A 20 parts Further, prepared water was added so that the solid content concentration would be 10% to prepare coating solution E for barrier layer.

Example 6
In Example 1, instead of the sheet-like support A, a sheet-like support C in which the following intermediate layer is formed is used, and instead of the barrier-layer coating liquid A, the barrier-layer coating liquid F having the following composition is used. A receiving sheet was obtained in the same manner as in Example 1 except that.
(Intermediate layer formation)
As a sheet-like support, art paper having a thickness of 150 μm (trade name: OK Kanto N, made by Oji Paper Co., Ltd., basis weight 174.4 g / m ² ) is used, and an intermediate layer coating liquid B having the following composition is applied on one side thereof. , coated so that the solid coating amount becomes 15 g / m ^2, to form an intermediate layer and dried. Next, on the intermediate layer, the barrier layer coating solution F is applied and dried so that the solid coating amount is 5 g / m ² to form a barrier layer, and the sheet-like support C Got.

Intermediate layer Preparation of Coating Solution B <br/> acrylonitrile and methacrylonitrile comprising a copolymer mainly composed of foamed hollow particles (average particle diameter 3.2 .mu.m, volumetric hollow rate 76%) 50 parts Polyvinyl alcohol ( Product name: PVA205, Kuraray) 20 parts styrene butadiene latex (trade name: PT1004, manufactured by Nippon Zeon,
(45% aqueous dispersion) 30 parts Further, prepared water was added so that the solid content concentration was 30% to prepare an intermediate layer coating solution B.

Preparation of barrier layer coating solution F Polyvinyl alcohol (trade name: PVA117, manufactured by Kuraray,
Saponification degree 99 mol%, polymerization degree 1700) 40 parts polyurethane aqueous dispersion (trade name: UX125, manufactured by Asahi Denka,
(Tg 105 ° C., solid content 30%) 50 parts active silicic acid aqueous solution A 10 parts Further, preparation water was added so that the solid content concentration was 10% to prepare a coating solution F for barrier layer.

Comparative Example 1
In Example 1, a receiving sheet was obtained in the same manner as in Example 1 except that the barrier layer coating solution G was used instead of the barrier layer coating solution A.
Preparation of barrier layer coating solution G Polyvinyl alcohol aqueous solution (trade name: PVA117, manufactured by Kuraray,
(Saponification degree 99 mol%, polymerization degree 1700, solid content 10%) 100 parts Further, preparation water was added so that the solid content concentration would be 6% to prepare a coating solution G for barrier layer.

Comparative Example 2
In Example 1, a receiving sheet was obtained in the same manner as in Example 1 except that instead of the barrier layer coating liquid A, a barrier layer coating liquid H having the following composition was used.
Preparation of coating liquid H for barrier layer Styrene acrylic emulsion (trade name: EK603, manufactured by Seiden Chemical,
Tg 20 ° C., solid content 40%) 80 parts active silicic acid aqueous solution A 20 parts Further, preparation water was added so that the solid content concentration was 20% to prepare coating liquid H for barrier layer.

Evaluation The following tests were conducted on the receiving sheets obtained in the above Examples and Comparative Examples. The obtained results are shown in Table 1.

[Image clarity]
A commercially available thermal transfer video printer (trade name: UP-50, manufactured by Sony Corporation) equipped with a sublimation type thermal transfer ink ribbon (trade name: UP-540, manufactured by Sony Corporation) was used. A black solid image was printed on the receiving sheet in a room temperature environment. Using a Macbeth reflection densitometer RD914, the print density of the black solid image was measured. The image clarity of the receiving sheet was evaluated according to the following criteria and shown in Table 1.
A: The black solid print density is 2.0 or more, and there is no problem in practical use.
○: The black solid print density is 1.7 or more and less than 2.0, which is practical.
X: The black solid print density is less than 1.7, which is not suitable for practical use.

[Image bleeding]
Using a commercially available thermal transfer video printer (trade name: UP-50, manufactured by Sony Corporation) equipped with a sublimation type thermal transfer ink ribbon (trade name: UP-540, manufactured by Sony Corporation), a black thin line was printed in a room temperature environment. After the printed matter was placed in an environment of 40 ° C. and 90% RH for 24 hours, the blur of the black thin line was visually evaluated and shown in Table 1.
(Double-circle): A black fine line is not blotted at all, and there is no problem in practical use.
○: The black thin line is slightly blurred but is practical.
X: The blur of the black thin line is remarkable and is not suitable for practical use.

[Image fingerprint resistance]
Using a commercially available thermal transfer video printer (trade name: UP-50, manufactured by Sony Corporation) equipped with a sublimation type thermal transfer ink ribbon (trade name: UP-540, manufactured by Sony Corporation), gray solid printing was performed in a room temperature environment. The finger was pressed strongly against the marking screen and placed in a 40 ° C. environment for 24 hours. The fingerprint trace after the test was visually evaluated.
A: There is no fingerprint mark, and there is no problem in practical use.
○: A trace of the fingerprint is left, but it is practical.
X: A fingerprint mark clearly remains and is not suitable for practical use.

  The receiving sheet of the present invention has a clear image and excellent durability, and can be used for photographic applications.

Claims (10)

  In a thermal transfer receiving sheet in which a barrier layer and an image receiving layer are sequentially laminated on at least one surface of a sheet-like support, the barrier layer uses a barrier layer coating solution containing a water-soluble polymer compound and an active silicic acid aqueous solution. A thermal transfer receiving sheet formed.   The thermal transfer receiving sheet according to claim 1, wherein the active silicic acid aqueous solution is an active silicic acid aqueous solution generated by subjecting an alkali metal silicate aqueous solution to dealkalizing metal treatment with an ion exchanger.   The thermal transfer receiving sheet according to claim 2, wherein the ion exchanger is a hydrogen type cation exchange resin.   The thermal transfer receiving sheet according to claim 2, wherein the alkali metal silicate aqueous solution is at least one selected from a sodium silicate aqueous solution, a potassium silicate aqueous solution, and a lithium silicate aqueous solution.   The thermal transfer receiving sheet according to any one of claims 1 to 4, wherein the active silicic acid aqueous solution is an active silicic acid aqueous solution adjusted to pH 2-12.   The sheet-like support is a paper base material mainly composed of cellulose pulp, and further provided an intermediate layer containing hollow particles between the paper base material and the barrier layer. The thermal transfer receiving sheet described.   The thermal transfer receiving sheet according to any one of claims 1 to 6, wherein the water-soluble polymer compound is a polyvinyl alcohol resin.   The thermal transfer receiving sheet according to any one of claims 1 to 7, wherein the barrier layer coating solution further contains a swellable inorganic layered compound.   The thermal transfer receiving sheet according to any one of claims 1 to 8, wherein the solid content of the active silicic acid is 0.3 to 35% by mass with respect to the total solid content of the coating liquid for the barrier layer.   The thermal transfer receiving sheet according to any one of claims 1 to 9, wherein the image receiving layer is formed using an aqueous coating liquid mainly composed of a thermoplastic resin.