JPH0460437B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention is applicable to, for example, image receiving sheets for thermal transfer recording, particularly for color copying used in video printers and the like that form characters and images on a receptor using electrical signals from a thermal head. This invention relates to an image receiving sheet. Copies thermally transferred using the image-receiving sheet for thermal transfer recording of the present invention are prevented from curling, and the unevenness caused by printing on the front surface does not remain on the back surface of the support. [Prior art] Conventionally, a transfer sheet having a transfer layer containing a sublimable or vaporizable dye and a receiving sheet are placed on top of each other, and the transfer sheet is heated to sublimate or vaporize the dye contained in the transfer layer and receive the dye. Dye the sheet,
Thermal transfer of forming dye images on receiver sheets is known. Specifically, in a transfer type thermal recording method using a heat source controlled by an electric signal such as a thermal head, as shown in FIG. A color copy is obtained by sandwiching a receiving sheet 1 having a support 12 between a drum 3 and a heat source 4, and transferring a coloring material from a layer 22 onto the image receiving layer 11 in response to an electric signal. . The image-receiving layer 11 differs depending on the content of the coloring material used. In the case of a heat-melting type coloring material containing a pigment, the support 12 itself may be used, and in the case of a sublimable basic dye type coloring material, the support 12 itself may be used. In the case of a sublimable disperse dye type coloring material, the white clay (activated clay) layer is made up of a coating layer of a polymeric material such as polyester. In conventional receptors, the surface of the image-receiving layer 11 had irregularities of 5 to 15 .mu.m and waviness of 10 to 20 .mu.m per mm due to uneven thickness of the support or surface irregularities.
This unevenness or waviness can only be improved to some extent even with surface treatment using a supercalender. For this reason, the coloring material transferred from the coloring material layer 22 has surface irregularities of 3 to 3.
If the waviness is 5 μm or more or the waviness is 10 μm or more per mm, not only heat-melting color materials but also sublimation color materials will not be transferred accurately according to the image signal, resulting in disturbances in image quality such as missing dots and missing dots. It gave a rough feel to the key (Japanese Patent Application Laid-Open No. 59-214696). The support 12 may be paper, a synthetic paper made of a stretched film of thermoplastic resin containing 40 to 50% by weight of inorganic fine powder (Japanese Patent Publication No. 40794/1983), a transparent polyethylene terephthalate film, or the surface of a transparent film. Coated synthetic paper, etc., whose surface is coated with an inorganic compound such as silica or calcium carbonate together with a binder, is used to improve whiteness and dyeability. Considering the after-use of the thermally transferred receiving sheet (copying, pencil writing, storage stability, etc.), inorganic fine image receiving sheets for thermal transfer recording are preferred in terms of strength, dimensional stability, and adhesion to the printing head. Synthetic paper, which is obtained by stretching a polyolefin resin film containing powder and has many fine voids inside the film, is preferable (Japanese Patent Laid-Open No. 60-245593).
No. 61-112693, patent application No. 62-25080). [Problems with conventional technology] This polyolefin resin-based synthetic paper is heated inside the film at a temperature lower than the melting point of the polyolefin material in order to provide a soft feel and improve adhesion to the print head and paper feeding/ejection properties. Void is formed using inorganic fine powder as the core. However, the melting point of polyolefin is higher than that of polyethylene terephthalate or polyamide (240-255
When printing with the printing head, the temperature of the surface of the receiving sheet is higher than the melting point, approaching 190-200°C, and the heat during printing causes the synthetic paper to shrink. It has been pointed out that there is a problem in which the thermally transferred receiving sheet curls on the printed inner surface. (Unexamined Japanese Patent Publication No. 60-245593,
61-283595). In addition, since the film has a structure with fine voids inside, the stress of unevenness of printing on the front surface is transmitted directly to the back side of the synthetic paper, so that a problem rarely occurs in which unevenness appears on the back side of the image receiving sheet. [Specific means for solving the problem] In the present invention, a plurality of sheets of synthetic paper are used as a support for the image receiving sheet, and a material sheet having higher rigidity than the synthetic paper is sandwiched between the synthetic papers. This prevents curling and transfer of printing stress to the back layer side. That is, the present invention provides an image-receiving sheet for thermal transfer recording in which an image-receiving layer is provided on the surface of a support, which satisfies the following (a) to (e). A receiving sheet is provided. (a) As the support, inorganic particles with a particle size of 3 microns or less are coated on the front and back surfaces of a rigid sheet selected from a thermoplastic resin sheet or paper with a Young's modulus of 26000 Kg/cm ² or more as measured by JIS P-8132. A laminate is used in which synthetic paper, which is made of a stretched polyolefin resin film containing fine powder and has a large number of voids formed with inorganic fine powder as cores by internal stretching of the film, is bonded together. (b) The synthetic paper has a void ratio of 20 to 50% calculated by the following method. Void ratio = Density of film before stretching - Density of void-containing resin sheet after stretching / Density of film before stretching ×
100 (%) (c) The rigid sheet of the support has a heat distortion temperature that is 30°C or more higher than the heat distortion temperature of the synthetic paper on the front and back sides. (d) The Young's modulus of synthetic paper is 9000 to 26000 Kg/cm ² . (e) The Young's modulus of the image-receiving sheet for thermal transfer recording is
It is 17000 to 40000 Kg/cm ² , and the Taber stiffness measured according to JIS P-8125 is 3 to 15 g-cm. (Synthetic paper for support) As synthetic paper for support, Japanese Patent Publication No. 46-40794,
Synthetic paper made of a stretched film of polyolefin resin containing inorganic fine powder and synthetic paper with an antistatic polymer coating layer provided on its surface, as described in JP-A-57-149363, JP-B-60-36173, etc. Although it is also possible to use inorganic fine powder from 0 to
The surface layer is a polyolefin resin film containing 25 wt%, and the polyolefin resin film contains a larger amount of inorganic fine powder with a specific surface area of 10,000 cm ² /g or more than the content of the surface layer, and contains many fine voids caused by stretching. A multilayer resin stretched film consisting of a core layer and a back layer made of a uniaxially stretched polyolefin film containing 25 to 75% by weight of inorganic fine powder, the surface layer having the longest length of the protrusions that protrude from the flat surface. The number of particles with a diameter of 50 microns or more is 10 or less per 0.1 ^m2 , and the compression ratio of the multilayer resin stretched film when pressed with a stress of 32Kg/ ^cm2 (atmosphere - temperature 23℃, relative humidity 50%) is 20
% to 40% is preferable in terms of no white spots and good printing surface and pencil writability. (Surface layer) The surface layer of the multilayer polyolefin resin stretched film on the side of the ink receiving layer is a uniaxially stretched film containing 0 to less than 10% by weight, preferably 5 to 8% by weight, of inorganic fine powder having a specific surface area of 10000 cm ² /g or more. It is a biaxially stretched resin film. For the back layer on the opposite side, if a uniaxially stretched resin film with the same composition is required to have pencil writability, a uniaxially stretched product containing 25 to 70% by weight of inorganic fine powder with a specific surface area of 10,000 cm ² /g or more is used. This is a resin film. The latter uniaxially stretched resin film of the back layer has many fine elongated voids with inorganic fine powder as the core, and has many fine cracks on the surface. Examples of the polyolefin resin constituting the surface layer and back layer include polyethylene, polypropylene, ethylene-propylene copolymer, and ethylene-propylene copolymer.
Vinyl acetate copolymer, poly(4-methylpentene-1), etc. can be used, and among these, polypropylene is preferable in terms of heat resistance, solvent resistance, and cost. This polyolefin contains polystyrene, polyamide, polyethylene terephthalate, ethylene-
Partial hydrolysates of vinyl acetate copolymers, ethylene-acrylic acid copolymers and their salts, vinylidene chloride copolymers such as vinyl chloride-vinylidene chloride copolymers, etc. may be blended. Examples of inorganic fine powders include calcium carbonate, calcined clay, diatomaceous earth, and calcined clay with an average particle size of 3 microns or less.
Talc, titanium oxide, barium sulfate, aluminum sulfate, silica, etc. can be used. As mentioned above, the multilayer polyolefin resin stretched film can include a back layer in addition to the surface layer and the core layer. As an example of synthetic paper that is a support for an image-receiving sheet for thermal transfer recording, on one side of a uniaxially stretched film sheet of core layer forming composition A,
A resin sheet of composition B for forming a surface layer is melt-laminated, and on the other side, a resin sheet of resin composition C for forming a back layer containing 25 to 70% by weight of inorganic fine powder is melt-laminated, and this multilayer sheet is obtained. It is obtained by once cooling, reheating, stretching in a direction perpendicular to the uniaxial stretching direction of the sheet A, and then heat-treating. By this stretching, the sheet of composition A is biaxially stretched, and a large number of voids (microvoids) are formed inside the sheet. On the other hand, the surface layer B and the back layer C are films stretched in the uniaxial direction, and have minute irregularities on the surface, and the surface smoothness (BEKK INDEX)
is about 500 to 15000 seconds. (A) Core layer composition (a) Polypropylene 50-95% by weight (b) Resin selected from high-density polyethylene, medium-density polyethylene, low-density polyethylene, and ethylene-vinyl acetate copolymer
0 to 30% by weight (c) Inorganic fine powder 10 to 25% by weight (B) Surface layer composition (a) Polypropylene 35 to 92% by weight (b) Polystyrene, high density polyethylene, medium density polyethylene, low density polyethylene, ethylene. Resin selected from vinyl acetate copolymer
0-30% by weight (c) Inorganic fine powder 0-10% by weight (C) Back layer (a) Polypropylene 25-75% by weight (b) Polystyrene, high-density polyethylene, medium-density polyethylene, low-density polyethylene, ethylene/acetic acid Vinyl copolymer 0 to 20% by weight (c) Inorganic fine powder 25 to 75% by weight 10~40% of total wall thickness, core layer thickness is 90~60%
It is preferable that If the surface layer and back layer are too thick, the compressibility of the core layer cannot be utilized, and if they are too thin, the surface smoothness will be too low and the adhesion between the head and the receiving sheet will become unstable. This multilayer polyolefin resin stretched film is
The core layer A has compressibility due to the large number of fine voids contained in it, and when pressed from the surface with a stress of 32 kg/cm ² in an atmosphere of a temperature of 23°C and a relative humidity of 50%, the thickness can be compressed to about 20-40%. Due to this compressibility, when a multilayer stretched polyolefin resin film is used as an image-receiving sheet for thermal transfer recording, the amount of ink received on the surface layer and the adhesion with the thermal transfer dye-containing film (thermal transfer ribbon) are improved, and the image for thermal transfer recording is improved. Even if there are convex portions on the surface of the receiving sheet, the convex portions are pushed into the interior, so that the resulting transferred image has excellent clarity. The amount of internal voids in this fine void-containing sheet is as follows: Void ratio = Density of film before stretching - Density of void-containing resin sheet after stretching / Density of film before stretching ×
When expressed as 100 (%), it is preferable that the void ratio is in the range of 20 to 50%, more preferably 25 to 50%. The surface layer may be made of only a polyolefin resin film that does not contain inorganic fine powder, but if necessary, inorganic fine powder may be mixed. Selected. The content of the inorganic fine powder in the surface layer is preferably selected so that the surface smoothness (Beck index) measured according to JIS P-8120 is about 500 to 15000 seconds. The inorganic fine powder mixed into the surface layer is selected to avoid creating large protrusions on the surface layer as much as possible.
325 mesh residue is preferably 10 ppm or less.
The particle size is preferably 3 microns or less. The protrusions from the surface of the surface layer B of the support 12 are:
^0.1m2 for those with a long diameter l of 50 microns or more
It is important that the number of defects be 10 or less because chipping of the thermally transferred image does not pose a practical problem. Even if an inorganic fine powder has an average particle size of 3 microns or less, there may be a small amount of particles with a particle size of 15 microns or 20 microns, or there may be a number of particles agglomerated together with a major diameter of 50 microns. There are things that are as large as microns. If these giant particles exist on the surface of the support 12 of the image-receiving sheet 1, the image-receiving layer 11 provided thereon will not be able to form a uniform film, and in severe cases will form pinholes, which will cause white spots. . The height h of the protrusion protruding from the flat surface of the resin surface 13 of the surface layer B of the support 12 is smaller than the long axis l of the inorganic fine powder. In terms of preventing white spots, it is preferable that the number of protrusions with a height h of 20 microns or more is 5 or less per 0.1 m ² . The back layer C on the opposite side of the front transferred image-receiving layer contains 25 to 75% by weight of inorganic fine powder, preferably 30% by weight, in order to provide slipperiness with the roll during transfer and writability to the back layer after transfer. The content is preferably 60% by weight, and it is preferably selected so that the surface smoothness (Beck index) measured according to JIS P-8120 is 50 to 2000 seconds. The wall thickness of synthetic paper is 30-80 microns, preferably
It is 40-80 microns. In addition, the Young's modulus of synthetic paper is
9000-26000Kg/ ^cm2 is preferable. (Rigid sheet) In order to cancel the shrinkage stress of the stretched multilayer polyolefin synthetic paper due to the heat of the printing head, the rigid sheet sandwiched between the synthetic papers has a Young's modulus higher than that of the synthetic paper (9000 to 26000 Kg/cm ² ). Sheet with high Young's modulus (26000Kg/cm2 or ^more ) made of polyethylene terephthalate, polyamide (nylon 6, nylon 6,6, nylon 6,10, nylon 6,12)
etc.) Thermoplastic resin sheets such as polyphenylene sulfide, polycarbonate, and isotactic polystyrene are used. These sheets may be stretched or reinforced with inorganic fine powder. You can also use paper. It is preferable to use a material having a heat distortion temperature 30° C. or more higher than that of polyolefin, which is the resin material of the synthetic paper, for this rigid sheet, since heat resistance can be imparted to the image-receiving sheet. The rigid sheet has a wall thickness of 5 to 120 microns, preferably 10 to 18 microns. [Support] The support is obtained by bonding the rigid sheet and synthetic paper together using a solvent adhesive so that the rigid sheet b is sandwiched between the synthetic papers a and c (see FIG. 3). Further, the resin of the material of the rigid sheet and the above-mentioned core layer composition A are co-extruded to form a sheet, which is then stretched in the longitudinal direction, and then the above-mentioned surface layer composition B is applied to the front and back layers. It can also be obtained by melt laminating the back layer composition C and then stretching it in the transverse direction. As the solvent-based adhesive, polyisocyanate adhesive, polyester adhesive, acrylic adhesive, ethylene/vinyl acetate copolymer aqueous emulsion, etc. can be used. (Image-receiving layer) As the resin forming the image-receiving layer, oligoester acrylate resin, saturated polyester resin, vinyl chloride/vinyl acetate copolymer, acrylic ester/styrene copolymer, epoxy acrylate resin, etc. are used. is dissolved in toluene, xylene, methyl ethyl ketone, cyclohexanone, etc. and used as a coating liquid. This coating liquid can contain an ultraviolet absorber and/or a light stabilizer to improve light resistance. Examples of ultraviolet absorbers include 2-(2'-hydroxy-3,3'-di-t-butylphenyl)-
5-chlorobenzotriazole, 2-(2-hydroxy-3,5-t-amyl phenyl)-2H-benzotriazole, 2-(2'-hydroxy-3'-
t-Butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',
5'-t-butylphenyl)-benzotriazole,
Examples include 2-(2'-hydroxy-3',5'-di-t-amyl phenyl)benzotriazole. Examples of light stabilizers include distearyl pentaerythritol diphosphorite, bis(2,4-di-
t-butylphenyl) pentaerythritol diphosphite, diphenylpentaerythritol diphosphite, cyclic neopentanetetrayl bis(octadecyl phosphite),
Tris(nonylphenyl)phosphite, 1-
[2-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]ethyl]
-4-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-2,2,
Examples include 6,6-tetramethylpiperidine. The amounts of these ultraviolet absorbers and light stabilizers added are preferably 0.05 to 10 parts by weight and 0.5 to 3 parts by weight, respectively, per 100 parts by weight of the resin constituting the image receiving layer 3. Furthermore, a release agent may be included in the image-receiving layer in order to improve the releasability from the thermal transfer sheet. As a mold release agent, polyethylene wax,
Solid waxes such as amide wax and Teflon powder; fluorine-based and phosphate-based surfactants;
Examples include silicone oil, but silicone oil is preferred. Although an oily silicone oil can be used as the silicone oil, a hardened type is preferable. Furthermore, in order to improve the whiteness of the image-receiving layer to further enhance the clarity of the transferred image, to provide writability to the surface of the heat-transfer sheet, and to prevent the transferred image from being re-transferred, the image-receiving layer contains White pigments can be added. As white pigments, titanium oxide, zinc oxide, kaolin clay, etc. are used.
These can be used in combination of two or more types.
As titanium oxide, anatase titanium oxide and rutile titanium oxide can be used, and examples of anatase titanium oxide include KA-10 and KA-
20, KA-15, KA-30, KA-35, KA-60,
Examples include KA-80 and KA-90 (both manufactured by Titan Kogyo Co., Ltd.), and examples of rutile titanium oxide include KR-
310, KR-380, KR-460, KR-480 (all manufactured by Titan Kogyo Co., Ltd.), and the like. The amount of the white pigment added is preferably 5 to 50 parts by weight per 100 parts by weight of the resin constituting the image receiving amount. The thickness of the image receiving layer 11 is generally 0.2 to 20 microns. (Thermal Transfer Image-Receiving Sheet) The thermal transfer image-receiving sheet of the present invention can be obtained by applying a coating solution for forming an image-receiving layer on the surface of a support and drying to scatter the solvent. The wall thickness of this image receiving sheet is 80 to 280 microns, and the Taber stiffness measured according to JIS P-8125 is 3 to 280 microns.
15 g-cm is preferable in terms of curl prevention and paper feeding/discharging properties. Hereinafter, the present invention will be explained in more detail with reference to Examples. Example of manufacturing synthetic paper 1 (1) 80% by weight of polypropylene with a melt index (MI) of 0.8 is blended with 20% by weight of calcium carbonate with an average particle size of 1.5 microns (A), and an extruder set at 270°C. After kneading, it is extruded into a sheet,
It was cooled using a cooling device to obtain a non-stretched sheet. This sheet was heated to 140°C and then stretched 5 times in the machine direction. (2) Average particle size in 95% by weight of polypropylene with MI4.0
Composition B for the surface layer mixed with 5% by weight of 1.5μ calcium carbonate was melt-kneaded in an extruder, and the extruded sheet was laminated on one side of a sheet stretched 5 times as much as (1), and On the opposite side of the stretched sheet, composition C for the back layer, which is a mixture of 60% by weight of polypropylene with MI4.0 and 40% by weight of calcium carbonate with an average particle size of 1.5μ, is melt-kneaded in a separate extruder and extrusion laminated. Then, after cooling to 60℃, heating to 162℃, stretching 7.5 times in the transverse direction with a tenter, annealing at 165℃, cooling to 60℃, and slitting the edges to form 3 layers (B/A/C). A synthetic paper with a wall thickness of 10/30/20 microns was obtained. The Betzke index of surface B of this synthetic paper is 6800 seconds, the whiteness as a support is 94.2%, and 32
The compression ratio against a stress of Kg/cm ² was 26%. In addition, the number of protrusions that protrude from the resin surface 13 of the surface layer B and have a longer diameter l of 50 microns or more is
There were 4 pieces per ^0.1m2 . Example 2 (1) 80% by weight of polypropylene with a melt index (MI) of 0.8 is blended with 20% by weight of calcium carbonate (A) having an average particle size of 1.5 microns, and after kneading in an extruder set at 270°C, extruded into a sheet,
It was cooled using a cooling device to obtain a non-stretched sheet. This sheet was heated to 140°C and then stretched 5 times in the machine direction. (2) MI4.0g/10min polypropylene 97.5% by weight
Composition B, which is a mixture of 2.5% by weight of barium sulfate with an average particle size of 0.3μ, is melt-kneaded in an extruder, and the extruded sheet is laminated on one side of a sheet stretched 5 times that of (1). On the opposite side of the stretched sheet, composition C, which is a mixture of 60% by weight of polypropylene with an MI of 4.0 and 40% by weight of calcium carbonate with an average particle size of 1.5μ, is melt-kneaded in another extruder, laminated by extrusion, and then cooled to 60°C. After that, it was heated to 162℃, stretched 7.5 times in the transverse direction with a tenter, and annealed at 165℃.
It was cooled to 60°C and the edges were slit to obtain a synthetic paper with a three-layer (B/A/C; wall thickness: 10/30/20 microns) structure. The Becs index of surface B of this synthetic paper was 5700 seconds, the whiteness as a support was 96.0%, and the compression ratio was 23%. In addition, the number of protrusions that protrude from the resin surface 13 of the surface layer B and have a longer diameter l of 50 microns or more is
There were 7 pieces per ^0.1m2 . Example 3 A synthetic paper with the physical properties shown in Table 1 was obtained in the same manner as in Example 1, except that a mixture of 98% by weight of polypropylene and 2% by weight of TiO ₂ with an average particle size of 0.25 microns was used as the composition for surface layer B. . Example 4 Same as Example 1 except for changing the die slit width, but the wall thickness is B/A/C; 40/80/40 microns.
A synthetic paper with a layered structure was obtained. Example 5 (1) 70% by weight polypropylene with a melt index (MI) of 0.8, 5% by weight high density polyethylene
Add 20% by weight of calcium carbonate (A) with an average particle size of 1.5 microns to the mixture (A), knead it in an extruder set at 270°C, extrude it into a sheet, and cool it with a cooling device to obtain an unstretched sheet. Ta. This sheet was heated to 140°C and then stretched 5 times in the machine direction. (2) Composition B, which is a mixture of MI4.0 polypropylene (C) and 50% by weight of polypropylene with MI4.0 and 50% by weight of calcium carbonate with an average particle size of 1.5 microns, is melt-kneaded in a separate extruder and placed in a die. Laminated and coextruded into a sheet, the surface of the sheet stretched 5 times as in (1)
Stack them so that (C) is on the outside, and MI4.0 on the other side.
Composition B, which is a mixture of 50% by weight of polypropylene of
After cooling to 60°C, heating to 160°C, stretching 7.5 times in the transverse direction with a tenter, annealing at 165°C, cooling to 60°C, slitting the edges, and creating a 4-layer structure (C/B/A /B; Wall thickness 5/10/
30/15 micron) synthetic paper was obtained. The number of protrusions was measured by the following method. (1) Shine an oblique light onto the surface of a synthetic paper sample cut into 20cm x 25cm pieces, visually locate and mark any protruding parts. (2) Observe the marked protruding part with a stereomicroscope set to 25x magnification, measure it with the No. 2 scale of a PEAK scale loupe, and find that the major axis is 50 μm.
Count the number of the above items. (3) Do this for two samples and calculate the composite number.
Number of protrusions (diameter) per ^0.1m2 . Next, the compressibility was measured by the following method. (1) A ring-shaped jig with a diameter of 6 cm ² is placed on the surface of the support.
The compression ratio was calculated by dividing the decrease in thickness when a pressure of 160 kg/cm ² was applied by the thickness before applying pressure. Measurements were made at a temperature of 23°C and a relative humidity of 50%.

[Table] Examples of rigid sheets 1 Polyethylene terephthalate with a wall thickness of 50μ 2
Axial stretched film. Young's modulus 47500Kg/cm ² Examples 2 Pulp paper. Wall thickness 50μ, weight 65g/m ² , Young's modulus
73000Kg/cm ² , heat resistance over 300℃. Example 3 Biaxially stretched polyphenylene sulfide film with a wall thickness of 40μ. Young's modulus 40000Kg/cm ² , heat resistance over 220℃. Manufacturing Examples of Supports On the back layer side of synthetic paper a shown in Table 2 obtained in each example,
After applying a mixture of solvent-type urethane adhesive "BLS-2080A" (resin) and BLS-2080B (curing agent) manufactured by Toyo Morton Co., Ltd. as an adhesive at a concentration of 3 g/ ^m2 , the rigidity shown in Table 2 was obtained. Pasting sheet b, further applying the adhesive on the back side of this rigid sheet, pasting the surface layer side of synthetic paper c shown in Table 2 to the adhesive,
A support shown in Table 2 was obtained. Examples 1 to 7, Comparative Examples 1 to 2 An image-receiving layer-forming composition having the following composition was coated with a wire bar on the surface layer side of the synthetic paper a of the support shown in Table 2 to give a dry thickness of 4 μm. It was coated and dried to obtain an image-receiving sheet for thermal transfer recording having the physical properties shown in Table 2. Byron 200 (Toyobo saturated polyester: Tg=
67℃) 5.3 parts by weight Byron 290 (Toyobo saturated polyester: Tg=
77℃) 5.3 parts by weight Vinyrite VYHH (Union Carbide's vinyl chloride-vinyl acetate copolymer) 4.5 parts by weight Titanium oxide (Titan Kogyo's KA-10) 1.5 parts by weight KF-393 (Shin-Etsu Silicone's amino-modified silicone oil) 1.1 Weight parts 10 parts by weight of epoxy acrylate resin, 20 parts by weight of oligoester acrylate resin, 2- as a sensitizer on one side (product name: 150 μm thick)
A coating solution consisting of 1.5 parts by weight of hydroxy-2-methylpropiophenone and 60 parts by weight of ethyl acetate was applied with a wire, dried with hot air at 60°C, and then irradiated with a 1kw high-pressure mercury lamp to harden to a thickness of 8 μm. A support was obtained by forming a resin layer. The image receiving and forming composition used in Example 1 was coated on the cured resin layer side of this support and dried in the same manner as in Example 1 to obtain a thermal transfer image receiving sheet having the physical properties shown in Table 2. Comparative Example 4 10 parts by weight of epoxy acrylate resin, 20 parts by weight of oligoester acrylate resin, and 2 parts by weight of oligoester acrylate resin were added to one side of polypropylene synthetic paper Yupo FPG150 (product name; wall thickness 150 μm) manufactured by Oji Yuka Synthetic Paper Co., Ltd. as a sensitizer. −
A coating solution consisting of 1.5 parts by weight of hydroxy-2-methylpropiophenone and 60 parts by weight of ethyl acetate was applied with a wire, dried with hot air at 60°C, and then irradiated with a 1kw high-pressure mercury lamp to harden to a thickness of 8 μm. A support was obtained by forming a resin layer. The image-receiving layer forming composition used in Example 1 was coated on the opposite side of the support from the cured resin layer, and dried in the same manner as in Example 1. Got a sheet. Comparative Example 5 10 parts by weight of epoxy acrylate resin, 20 parts by weight of oligoester acrylate resin, and 2 parts by weight of oligoester acrylate resin were applied to both sides of polypropylene synthetic paper Yupo FPG150 (product name; wall thickness: 150 μm) manufactured by Oji Yuka Synthetic Paper Co., Ltd. −
A coating solution consisting of 1.5 parts by weight of hydroxy-2-methylpropiophenone and 60 parts by weight of ethyl acetate was applied with a wire, dried with hot air at 60°C, and then irradiated with a 1kw high-pressure mercury lamp to coat the front and back sides with a thickness of 1.5 parts by weight. 8μm
A support was obtained by forming a cured resin layer. On one side of the cured resin layer of this support, Example 1
The image-receiving layer forming composition used in Example 1 was applied and dried in the same manner as in Example 1 to obtain a thermal transfer image-receiving sheet having the physical properties shown in Table 2. These thermal transfer image-receiving sheets were evaluated by the following method. The results are shown in Table 2. (1) Image judgment method: The image-receiving sheet prepared in each example and comparative example was overlaid with transfer film “TTF Cyan” (trade name) manufactured by Mitsubishi Paper Mills Co., Ltd. coated with sublimable dye and dried, and then thermally tilted. Testing machine (Toyo Seiki Type-HG-
100), the hot plate was heated at 5 points from 120° C. to 10° C. and heated for 2 seconds at a pressure of 0.5 kg/cm ² to obtain a transferred image. The density of the obtained transferred image was measured using a Macbeth densitometer and evaluated on the following five scales. 5: Very good. 4: Good 3: Practically speaking, there are no branches. 2: There are some practical problems. 1: Not practical. Evaluation of curl: The four edges of the image receiving sheet prepared in each example and comparative example were transferred using a Hitachi color video printer (VY-50) and left in a 50% atmosphere at 23°C for 24 hours. The average value of the lifting height was determined. Whether or not the surface stress of the transferred image transfers to the back layer of the support: Visually determine the presence or absence of unevenness on the back layer of the synthetic paper of the receiving sheet on the opposite side of the transferred image used for curl evaluation. Paper feeding and discharging properties: The paper feeding properties and paper discharging properties of the thermal transfer image-receiving sheet when transferred to the Hitachi color video printer (VY-50) were investigated. 5: Very good. 3: No practical problem. 1: Not suitable for practical use.

【table】

Claims (1)

[Scope of Claims] 1. An image-receiving sheet for thermal transfer recording in which an image-receiving layer is provided on the surface of a support, which satisfies the following (a) to (e): Image receiving sheet. (a) As the support, inorganic particles with a particle size of 3 microns or less are coated on the front and back surfaces of a rigid sheet selected from a thermoplastic resin sheet or paper with a Young's modulus of 26000 Kg/cm ² or more as measured by JIS P-8132. A laminate is used in which synthetic paper, which is made of a stretched polyolefin resin film containing fine powder and has a large number of voids formed with inorganic fine powder as cores by internal stretching of the film, is bonded together. (b) The synthetic paper has a void ratio of 20 to 50% calculated by the following method. Void ratio = Density of film before stretching - Density of void-containing resin sheet after stretching / Density of film before stretching x
100 (%) (c) The rigid sheet of the support has a heat distortion temperature that is 30°C or more higher than the heat distortion temperature of the synthetic paper of the front and back layers. (d) The Young's modulus of synthetic paper is 9000 to 26000 Kg/cm ² . (e) The Young's modulus of the image-receiving sheet for thermal transfer recording is
It is 17000 to 40000 Kg/cm ² , and the Taber stiffness measured according to JIS P-8125 is 3 to 15 g-cm. 2. The image-receiving sheet for thermal transfer recording according to claim 1, wherein the rigid sheet is a biaxially stretched sheet of polyethylene terephthalate. 3 The synthetic paper has a surface layer (the side in contact with the image-receiving layer) of a polyolefin resin film containing 0 to 10 wt% of inorganic fine powder with a particle size of 3 microns or less, and the inorganic fine powder with a specific surface area of 10,000 cm ² /g or more. The core layer of the polyolefin resin film contains more than the surface layer and contains many voids caused by stretching, and 25 to 75% by weight of inorganic fine powder.
A multilayer resin stretched film consisting of the back layer of a uniaxially stretched polyolefin film containing polyolefin, the surface layer of which has no more than 10 protrusions ^per 0.1 m2 with a maximum length of 50 microns or more that protrudes from the flat surface. 2. The image-receiving sheet for thermal transfer recording according to claim 1, wherein the multilayer resin stretched film has a compression ratio of 20% to 40% under a stress of 32 kg/cm ² . 4. The thickness of the image-receiving layer is 0.2 to 20 microns,
The synthetic paper has a wall thickness of 30 to 80 microns, the rigid sheet has a wall thickness of 5 to 120 microns, and the image receiving sheet for thermal transfer recording has a wall thickness of 80 to 270 microns. The image-receiving sheet for thermal transfer recording according to item 1.