JPH0725174A - Heat sensitive transfer image recording sheet - Google Patents

Abstract

PURPOSE:To obtain a heat sensitive transfer image recording sheet having small curl against heat by providing a film surface layer containing a specific amount of petroleum resin and a heat transfer image receiving layer on a thermoplastic resin film containing a specific amount of petroleum resin. CONSTITUTION:A thermoplastic resin film surface layer 10 containing less than 3wt.% of petroleum resin and a heat transfer image receiving layer 6 are laminated on a surface of a thermoplastic resin film base layer 9 containing 3-60wt.% of petroleum resin to form a heat sensitive transfer image recording sheet. The thermoplastic resin includes, for example, polyolefin resin such as polyethylene, polypropylene, ethylene-propylene copolymer, etc. The resin to be blended in the film includes, for example, hydrocarbon resin or its hydrogenated matter obtained by polymerizing raw material obtained by thermal decomposition of petroleum with catalyst, and the raw material includes, for example, terpene, cyclopendadiene, styrene, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive transfer image recording sheet (heat-sensitive transfer image receiving sheet), and more particularly to a heat-sensitive transfer image recording sheet which is difficult to curl even if heat is applied during transfer recording. is there.

[0002]

2. Description of the Related Art In general, a thermal transfer recording method sublimates or vaporizes a dye contained in a color material layer by heating a transfer material comprising a color material layer containing a sublimable or vaporizable dye and a substrate supporting the dye material layer. Then, the image-receiving recording sheet is dyed to form a dye image. In particular,
As shown in FIG. 1, a thermal transfer body (1), a thermal transfer image recording sheet (2) comprising a thermal transfer image receiving layer (6) and its support (7), a drum (8) and a heat source (3). When the coloring material layer (5) is heated by a heat source such as a thermal head which can be controlled by an electric signal, the dye contained in the coloring material layer (5) is sublimated or vaporized. Then, the thermal transfer image receiving layer (6) is dyed and thermal recording transfer is performed. The material of the thermal transfer image receiving layer 6 differs depending on the type of coloring material to be dyed thereon. For example, when the coloring material is a heat melting type, the support (7) itself may be used as the image receiving layer. When the coloring material is a sublimable disperse dye type, a polymer material coating layer such as polyester can be used as the thermal transfer image receiving layer.

However, in the conventional thermal transfer image recording sheet (2), since the support (7) has unevenness in thickness and unevenness, the surface of the thermal transfer image receiving layer (6) itself has a thickness of 5 to 15 μm.
There were unevenness of m and waviness of 10 to 20 μm per 1 mm. Such unevenness and waviness are somewhat improved by the surface treatment with a super calendar, but there is a limit. For example, the surface of the thermal transfer image-receiving layer still has 3 to 3
There is unevenness of 5 μm or more or waviness of 10 μm or more per 1 mm. Therefore, the coloring material transferred from the coloring material layer (5) is not only a heat-melting coloring material but also a sublimable coloring material depending on the image signal. The image was not accurately transferred, and the image quality was disturbed by missing dots or missing dots in the image, and the intermediate tone had a grainy feel. Further, as the support, an opaque synthetic paper (Japanese Patent Publication No. 46-40794) composed of paper or a stretched film of a propylene resin containing inorganic fine powder, or a transparent polyethylene terephthalate film or a transparent polyolefin film is used. A coated synthetic paper or the like is used in which an inorganic compound such as silica or calcium carbonate is coated on the surface together with a binder to improve whiteness and dyeability.

However, after-use of the heat-sensitive transfer image recording sheet after heat-sensitive transfer (copying, pencil writing, storability, etc.)
In consideration of, strength, dimensional stability,
From the viewpoint of adhesion to the print head, it is said that synthetic paper having a large number of microvoids inside is obtained by stretching an inorganic fine powder-containing polyolefin resin film (Japanese Patent Laid-Open No. 245593/1985). Kai 61-
112693, JP-A-63-193836). The synthetic paper obtained by stretching such a polyolefin resin film has opacity and softness, and in order to improve the adhesion with the print head and the paper feeding / discharging property, the melting point of the polyolefin resin used as the material. The film is stretched at a lower temperature to form microvoids inside the film.

[0005]

However, the surface temperature of the receiving sheet during transfer recording is 19 even though it is short.
The melting point of the polyolefin resin film is 167 ° C. or less, which is considerably lower than that of polyethylene terephthalate or polyamide (240-255 ° C.), so that heat transfer was performed by heat during transfer recording. There is a drawback that the heat-sensitive transfer image recording sheet curls toward the printed inner surface (JP-A-60-245593 and JP-A-61-283593). On the other hand, in order to prevent such curl, the stretching temperature may be set in the vicinity of the melting point of the base resin, but in this case, the opacity and softness of the base resin are deteriorated. There are drawbacks. SUMMARY OF THE INVENTION It is an object of the present invention to solve the conventional problems as described above and to provide a novel thermal transfer image recording sheet which has a small curl even when heat is applied during transfer recording and which poses no practical problem.

[0006]

[Means for Solving the Problems]

[Summary of the Invention] As a result of intensive studies in view of the above problems, the present inventors have found that a thermoplastic resin film containing 3 to 60% by weight of a petroleum resin has a small curl. However, if the content of petroleum resin is increased in order to reduce the curl, the phenomenon of the film sticking to various cooling rolls or heating rolls during the film production process (blocking) occurs, and the curl of the film decreases, but the surface There is a problem that the outer surface becomes rough and the appearance becomes worse. Then, by laminating a thermoplastic resin film containing less than 3% by weight of a petroleum resin as a surface layer on the surface of a thermoplastic resin film substrate containing 3 to 60% by weight of a petroleum resin, various rolls at the time of film production can be obtained. Thus, a heat-sensitive transfer image recording sheet which is free from surface blocking and has a small curl is obtained. That is, the present invention provides a thermoplastic resin film surface layer (10) containing less than 3% by weight of a petroleum resin on the surface of a thermoplastic resin film base layer (9) containing 3 to 60% by weight of a petroleum resin. A heat-sensitive transfer image recording sheet comprising a heat transfer image-receiving layer (6) formed on the surface layer of the support.

DETAILED DESCRIPTION OF THE INVENTION [I] Thermal Transfer Image Recording Sheet The thermal transfer image recording sheet of the present invention contains less than 3% by weight of petroleum resin on the surface of a thermoplastic resin film containing petroleum resin. These thermoplastic resin films are laminated, and a thermal transfer image receiving layer is formed on the surface of the support. [II] Support Layer The support layer used in the thermal transfer image recording sheet of the present invention contains less than 3% by weight of a petroleum resin on the surface of a thermoplastic resin film containing 3 to 60% by weight of a petroleum resin. It has a structure in which thermoplastic resin films are laminated.

(1) Constituent Material The material constituting the thermoplastic resin film containing a petroleum resin is a thermoplastic resin and a petroleum resin, preferably a thermoplastic resin containing an inorganic fine powder and a petroleum resin. (A) Thermoplastic resin As the thermoplastic resin forming the thermoplastic resin film, a polyolefin resin is usually used. Examples of such polyolefin resin include polyethylene, polypropylene, ethylene / propylene copolymer, ethylene / vinyl acetate copolymer, propylene / butene-1 copolymer, poly (4-methylpentene-1), polystyrene and the like. Can be mentioned. Of course, in addition to such a polyolefin resin, other thermoplastic resins such as high melting point polyamide, polyethylene terephthalate, and polybutylene phthalate can also be used, but the effect of curling by the addition of petroleum resin is Demonstrated when using.

(B) Inorganic fine powder Since a large number of microvoids (fine cavities) are formed inside the thermoplastic resin film, the inorganic fine powder blended in the thermoplastic resin includes calcium carbonate and calcined clay. , Diatomaceous earth, talc, titanium oxide, barium sulfate,
Aluminum sulfate, silica, etc. can be mentioned. The average particle size of these inorganic fine powders is generally 10 μm.
Hereafter, those having a thickness of 4 μm or less are preferably used. (C) Petroleum resin As the petroleum resin blended in the thermoplastic resin film, a hydrocarbon resin (or hydrogenated product thereof) obtained by polymerizing a raw material obtained by thermal decomposition of petroleum using a catalyst is used. Well, these raw materials are generally terpene, cyclopentadiene, styrene, methylstyrene, vinyltoluene, indene, methylindene,
It consists of a mixture of resin-forming monomers such as butadiene, isoprene, piperylene, pentylene,
The resin may be a homopolymer or a mixture of one of these monomers, or a copolymer of several types.

JET 1, Volume 37, No 2 (1989)
Pp. 75-79, petroleum resins are classified from the raw material side, and aliphatic petroleum resin (C ₅ petroleum resin) aromatic petroleum resin (C ₉ petroleum resin) aliphatic / aromatic Alternatively, aliphatic / alicyclic copolymer type petroleum resins (C ₅ type / C ₉ type petroleum resins) cyclopentadiene type petroleum resins (DCPD type petroleum resins) are roughly divided into hydrogenated petroleum resins obtained by hydrogenating these resins.

The petroleum resin used in the present invention means the above-mentioned hydrocarbon resin, and includes coke oven gas, coal tar distillate and pyrolyzed petroleum feedstock, essentially pure hydrocarbon feedstock, and turpentine oil. A hydrocarbon polymer derived from a derived hydrocarbon raw material or turpentine oil, etc., and typical hydrocarbon resins include, for example, coumarone-indene resin, C ₅ petroleum fraction, styrene copolymer, cyclopentadiene. Resin, terpene resin, etc. can be mentioned. Regarding these resins, Kirk Osmer, "Encyclopedia of Chemical Technology," 3rd Edition, Vol. 11, pp. 242-255 (19)
1966).

The coumarone-indene resin is a hydrocarbon resin, a phenol-modified coumarone-indene resin, or a derivative thereof obtained by polymerizing a resin-forming material present in a distillate of coal tar recovered from a coke oven. Dicyclopentadiene resin is a homopolymer resin or copolymer resin of cyclopentadiene from coal tar fraction or cracked petroleum gas, and the cyclopentadiene resin is produced by holding a cyclopentadiene-containing raw material at a high temperature for a considerably long time. Depending on the holding temperature, either a dimer, a trimer or a high polymer can be obtained. Terpene resins are rational formula, polymers of pentenes hydrocarbon of C ₁₀ H _16, and phenol-modified terpene resin present in most essential oils and containing oil resin of the plant, for example α- pinene, beta Mention may be made of pinene, dipentene, limonene, myrcelle, bornylene, camphene and similar terpenes. Among these, hydrogenated petroleum resins having the above-mentioned softening point (ring and ball method) of 70 to 150 ° C. are particularly preferable in the present invention, and those having a softening point of 115 to 150 ° C. are more preferable from the viewpoint of anti-blocking.

As the hydrogenated petroleum resin, trade name "ALCON" manufactured by Arakawa Chemical Industry Co., Ltd., trade name "CRYALON" manufactured by Yasuhara Chemical Co., Ltd., trade name "ESCOLETS" manufactured by Tonex Co., Ltd., and Maruzen Petrochemical Co., Ltd. "Marukalets" manufactured by Co., Ltd., etc. are available. These petroleum resins are generally
It is blended by melting and kneading with a thermoplastic resin. (2) Formation of Thermoplastic Resin Film The support layer used in the heat-sensitive transfer image recording sheet of the present invention has a petroleum resin content of 3 to 60% by weight and a thermoplastic resin content of 97 to 40.
A mixture of 1% by weight, a mixture of 0 to 3% by weight of a petroleum resin, and a mixture of 97 to 100% by weight of a thermoplastic resin are melt-kneaded by separate extruders and laminated and molded into a film.

Such a thermoplastic resin film is obtained by inflation molding, T-die molding, or one obtained by those molding methods in a uniaxial direction of 1.3 to 8 times. It can be produced by stretching, biaxially extending in the longitudinal and transverse directions by 1.3 to 12 times in each direction, or by stacking them in combination. Among these thermoplastic resin films, in consideration of after-use (copy, pencil writing, storage stability, etc.) of the heat-sensitive transfer image recording sheet after heat-sensitive transfer,
As the support, from the viewpoint of strength, dimensional stability, and adhesion to the print head, a synthetic paper having many microvoids (fine cavities) inside obtained by stretching a thermoplastic resin film containing inorganic fine powder Is preferably used.

As such a synthetic paper, a petroleum resin as a base material layer is 3 to 60% by weight, preferably 5 to 50% by weight, an inorganic fine powder is 5 to 60% by weight, preferably 10 to 45% by weight, and thermoplastic. Resin 20-92
A uniaxially stretched film (B) obtained by stretching a thermoplastic resin containing 5% by weight, preferably 25 to 85% by weight, 3 to 10 times, preferably 4 to 7 times is used on the surface of the base material layer. As the surface layer (A), a petroleum resin is 0 to less than 3% by weight, preferably 0 to 2.5% by weight, an inorganic fine powder is 5 to 80% by weight, preferably 10 to 60% by weight, and a thermoplastic resin is 30%.
~ 95 wt%, preferably 50-90 wt% of the mixture, melt-kneaded with an extruder, after extrusion lamination on the surface or both sides of the uniaxially stretched film (B) using a die, after lamination, It is a film containing fine voids obtained by stretching the laminated film in a direction perpendicular to the stretching direction of the uniaxially stretched film of the thermoplastic resin by a tenter at 3 to 15 times, preferably 4 to 12 times.

In this case, by laminating the thermoplastic resin film for the surface layer, the thermoplastic resin film for the substrate layer conceals the surface roughness caused by blocking on the heating roll of the uniaxial stretching device, and there is no surface roughness. A fine void-containing film having an excellent appearance can be obtained.

Inorganic fine powder 5 to 45 is used as a base material layer.
Using a uniaxially stretched film (B) obtained by stretching a thermoplastic resin containing 10% by weight, preferably 8 to 30% by weight, 3 to 10 times, preferably 4 to 7 times, the surface of this substrate layer or Petroleum resin on both front and back sides is 3 to 60% by weight, preferably 5 to 50% by weight, inorganic fine powder is 10 to 80% by weight, preferably 15 to 65% by weight, and thermoplastic resin is 20 to 87%.
% By weight, preferably 25-80% by weight of mixture (A ₂ ).
And 0 to less than 3% by weight of petroleum resin, preferably 0 to 2.
5% by weight, inorganic fine powder 5-80% by weight, preferably 10-60% by weight, thermoplastic resin 30-95% by weight,
Preferably, 50-90% by weight of the mixture (A ₁ ) melt-kneaded by different extruders is supplied to one die, and the melt-laminated in the die has (A ₁ ) on the surface. Finely obtained by extruding and laminating the laminated film so that it is laminated, and then stretching the laminated film in a direction perpendicular to the stretching direction of the uniaxially stretched film of the thermoplastic resin by a tenter at 3 to 15 times, preferably 4 to 12 times. It is a void-containing film. In this case, if the surface layer thermoplastic resin (A ₁ ) is not laminated on the surface of the laminated film to be extrusion-laminated, the laminated film will be blocked by the cooling roll after lamination, and the resulting fine voids will be obtained. The surface of the contained film is roughened and the appearance is deteriorated.

Petroleum resin is 3 to 60% by weight, preferably 5 to 50% by weight, inorganic fine powder is 5 to 60% by weight, preferably 10 to 45% by weight, and thermoplastic resin is 20 to 92% by weight.
% By weight, preferably 25 to 85% by weight of the thermoplastic resin film for base material layer (B), 0 to less than 3% by weight of petroleum resin, preferably 0 to 2.5% by weight and 5% of inorganic fine powder. -80 wt%, preferably 10-60 wt%, and a thermoplastic resin film for surface layer (A) containing a thermoplastic resin of 30-95 wt%, preferably 50-90 wt%, and then sequentially Or at the same time, 3 to 10 times in the longitudinal direction, preferably 4 to 7 times, and 3 to 15 times in the lateral direction, preferably 4 to 1
It is a film containing fine voids, which is a laminated film obtained by biaxially stretching the film twice. In this case, when the thermoplastic resin film for surface layer (A) is not laminated, a preheating roll for uniaxial stretching, specifically, a heating roll of a uniaxial stretching device utilizing the peripheral speed difference of the roll, The thermoplastic resin film (B) for the base material layer sticks (blocking phenomenon)
As a result, the surface of the obtained film containing fine voids is roughened and the appearance is deteriorated.

(3) Structure It is preferable that the thermoplastic resin film is a fine void-containing resin film having a large number of micro voids (fine voids) formed therein. Fine voids The fine void content of the fine void-containing resin film means that the porosity calculated by the following formula is 10 to 60%, preferably 15:
~ 50%.

[0020]

[Formula 1] The presence of these microvoids gives the support cushioning properties, improves the contact between the thermal head (3) and the heat-sensitive transfer image recording sheet, gives a clear image, and imparts heat insulation properties to the stretched film. However, heat shrinkage is prevented.

(4) Thickness The thickness of the support layer (thermoplastic resin film) is generally 50 to 500 μm, preferably 55 to 250 μm. By providing a thermal transfer image receiving layer on the surface of this support, a thermal transfer image recording sheet can be obtained. As a material for forming a thermal transfer image receiving layer, a polymer material such as an acrylic resin and a polyolefin resin is used as a material having good transferability to a heat-melting color material containing a pigment, and a sublimation property or a vaporization property is used. As the resin showing the dyeability with the organic dye, a polymer material such as polyester or a material such as activated clay is used. For example, as the acrylic resin, a). Acrylic copolymer resin b). Mixture of the following 1) to 3) 1) Acrylic copolymer resin 2) Amino compound having amino machine 3) Epoxy compound c). A mixture of the above a) or b) and an inorganic or organic filler (filler) is used.

Examples of the acrylic copolymer resin monomer include dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, dibutylaminoethyl acrylate, dimethylaminoethyl acrylamide, diethylaminoethyl methacrylamide, and dimethylaminoethyl methacrylamide. To be Other vinyl monomers of the acrylic copolymer resin include styrene, methyl methacrylate, ethyl acrylate, n-butyl acrylate, tert-butyl acrylate, ethyl methacrylate, vinyl chloride, ethylene, acrylic acid, Methacrylic acid, itaconic acid, acrylonitrile, methacrylamide, etc. may be mentioned. Examples of the 2) amino compound in the component b) include polyalkylene polyamines such as diethylene triamine and triethylene tetracumin, polyethylene imine,
Ebichlorohydrin adducts of ethylene urea and polyamine polyamide [trade names include Kaymen 557H from Dick Hercules, AF- from Arakawa Hayashi Chemical Industry Co., Ltd.]
100], an aromatic glycidyl ether or ester adduct of polyamine polyamide [trade names are Sanmide 352, 351 and X-2300 manufactured by Sanwa Chemical Co., Ltd.]
-75, Ebikyu-3255] manufactured by Shell Chemical Co., Ltd., and the like can be used.

Further, as the epoxy compound of 3) in the component b), diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, diglycidyl phthalate, polypropylene glycol diglycidyl ether, trimethylolpropane triglycidyl. Ether etc. can be used. As the inorganic filler in the component c), synthetic silica such as white carbon having an average particle size of 0.5 μm or less, calcium carbonate, clay,
Inorganic pigments such as talc, aluminum sulfate, titanium dioxide, and zinc oxide can be used, and preferably synthetic silica such as white carbon and inorganic pigments such as light calcium carbonate having an average particle size of 0.2 μm or less can be used. Although various polymer fine particles are used as the organic filler, the particle diameter thereof is preferably 10 μm or less. Examples of the fine particle polymer that constitutes the organic filler include, for example, methyl cellulose, ethyl cellulose, polystyrene, polyurethane, urea-formalin resin, melamine resin, phenol resin, iso (or diiso) butylene / maleic anhydride copolymer, styrene / Maleic anhydride copolymer, polyvinyl acetate, polyvinyl chloride, vinyl chloride
Examples thereof include vinyl acetate copolymers, polyesters, polyacrylic acid esters, polymethacrylic acid esters, and styrene / butadiene / acrylic copolymers.

These fillers are usually used in a proportion of 30% by weight or less. In particular, the inorganic filler is treated with a non-ionic, cationic or amphoteric activator such as funnel oil, sodium dodecyl sulfate, organic amine, metal soap sodium lignin sulfonate on the surface thereof to form an ink for the thermal transfer image receiving sheet. Leakage is improved and it can be preferably used. Further, a mixed resin of saturated polyester and vinyl chloride-vinyl acetate copolymer is used. Examples of the saturated polyester include Pylon 200, Pylon 290,
Pylon 600 etc. (above, Toyobo), KA-1038
C (manufactured by Arakawa Chemical Co., Ltd.), TP220, TP235 (above, manufactured by Nihon Gosei) and the like are used. The vinyl chloride-vinyl acetate copolymer preferably has a vinyl chloride component content of 85 to 97 wt% and a degree of polymerization of about 200 to 800. The vinyl chloride-vinyl acetate copolymer is not necessarily limited to a copolymer containing only a vinyl chloride component and a vinyl acetate component, and may contain a vinyl alcohol component, a maleic acid component and the like. Such vinyl chloride-vinyl acetate copolymers include, for example, S-REC A, S-REC C, S-REC M (all manufactured by Sekisui Chemical Co., Ltd.), and Vinylite VAG.
H, Vinyl Light VYHH, Vinyl Light VMGH, Vinyl Light VYHD, Vinyl Light VYLF, Vinyl Light VYN
S, Vinylite VMCC, Vinylite VMCA, Vinylite VAGD, Vinylite VERR, Vinylite VRO
H (above, Union Carbide), Denka Vinyl 1
000GKT, Denka Vinyl 1000L, Denka Vinyl 1000CK, Denka Vinyl 1000A, Denka Vinyl 1000LK ₂ , Denka Vinyl 1000AS, Denka Vinyl 1000MT ₂ , Denka Vinyl 1000CSK, Denka Vinyl 1000CS, Denka Vinyl 1000GK,
Denka Vinyl 1000GSK, Denka Vinyl 1000G
S, Denka Vinyl 1000 LT ₂ , Denka Vinyl 100
0D, Denka vinyl 1000W (above, manufactured by Denki Kagaku Kogyo), and the like. The mixing ratio of the saturated polyester and the vinyl chloride-vinyl acetate copolymer is 100 parts by weight of the vinyl chloride-vinyl acetate copolymer and 9 parts by weight of the saturated polyester.
It is preferably from 100 to 100 parts by weight.

The thermal transfer image receiving layer (6) is formed by coating the outermost surface layer side of the support (7) and drying. For coating, a normal coating device such as a blade coater, an air knife coater, a roll coater, or a bar coater, or a size press or a gate roll device is used. The thickness of the thermal transfer image receiving layer is 0.2 to 20 μm.
m, preferably 0.5 to 10 μm.

(5) Other Treatments If necessary, the surface of the heat-sensitive transfer image recording sheet may be further smoothed by a calendar treatment. An overcoat layer may be provided on the heat transfer image receiving layer for the purpose of protecting the recording layer, and the back side of the heat transfer image recording sheet may be treated with an adhesive to form an adhesive label. Various known techniques in the field of manufacturing image recording sheets can be added as necessary.

(6) Usage The thermal transfer image recording sheet thus obtained is used as a recording medium in a thermal transfer recording method useful for recording a single color image or a full color image with continuous gradation by a thermal recording head. Used, specifically, it can be used as a recording medium for video printers, thermal facsimiles, and the like.

[0028]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples below. The various physical properties in the examples and comparative examples are measured by the following evaluation methods. [I] Evaluation method <Curl height> Hitachi Color Video Printer V was used for the laminated resin sheet and the thermal transfer image recording sheet to be measured.
An image transferred with D-50 (trade name) is cut into a rectangle with a width of 200 mm in the MD (machine direction) direction and a width of 120 mm in the TD (traverse direction) direction, and this is cut at a temperature of 23 ° C. and a humidity of 50%. The floating height (mm) when left on a flat surface for 24 hours under the conditions is measured.

<Surface Roughness Due to Blocking> The degree of surface roughness due to blocking of the obtained heat-sensitive transfer image recording sheet was visually observed and evaluated according to the following five grades. 5: There is no surface roughness. 4: Almost no roughness. 3: There is no problem in practical use. 2: There is a problem in practical use. 1: Surface roughness is large and defective.

<Gradation> On the surface of the obtained thermal transfer image recording sheet, a printer manufactured by Okura Electric Co., Ltd. (dot density: 6 dots / mm, applied power: 0.23 W / dot)
(See Fig. 1)
The Macbeth concentration was investigated. The gradation of the obtained print when the pulse width was 1.3 milliseconds was visually measured and evaluated according to the following 5 grades. 5: Very good. 4: Good. 3: There is no problem in practical use. 2: There is a problem in practical use. 1: Bad.

[II] Experimental Example (Example 1) (1) Melt flow rate (MFR) was 0.8 g / 1.
55% by weight of polypropylene in 0 minutes has an average particle size of 1.5
15% by weight of heavy calcium carbonate and petroleum resin "Arcon" P-125 (softening temperature 12
5 wt.%) Was blended in an extruder set at a temperature of 270.degree. C., extruded into a sheet by a die, and cooled by a cooling device to obtain an unstretched sheet. Next, this sheet was heated to a temperature of 150 ° C. and then stretched 5 times in the longitudinal direction to obtain a 5 times stretched sheet for the base material layer (B). (2) 55% by weight of polypropylene with MFR of 4.0
A mixture of 45% by weight of ground calcium carbonate having an average particle size of 1.5 μm is melt-kneaded by an extruder set at a temperature of 220 ° C., then extruded into a sheet by a die and uniaxially stretched. The front surface layer (A) was prepared and laminated on one side of the uniaxially stretched substrate layer (B) (1).

On the opposite side, 220% by weight of polypropylene containing 55% by weight of MFR of 4.0 and 45% by weight of ground calcium carbonate having an average particle size of 1.5 μm were mixed.
After melt-kneading with an extruder set to a temperature of ℃, extruded into a sheet form by a die to prepare a surface layer (C) before uniaxially stretching, which is a base layer for uniaxially stretching (1) It was laminated on the back side of (B). Next, this laminated sheet was cooled to a temperature of 60 ° C., then heated to a temperature of 162 ° C., stretched to 7.5 times in the transverse direction with a tenter, and then annealed at a temperature of 167 ° C. to 60 ° C. The temperature of the film is cooled to a temperature of 3, and the ears are slit to form a three-layer thermal transfer image recording sheet support (the thickness of A / B / C is 15 μm).
m / 120 μm / 15 μm) was obtained.

Preparation of Coating Solution for Thermal Transfer Image Receiving Layer A thermal transfer image receiving layer having the following composition was formed on the surface layer (A) of the above-mentioned support for thermal transfer image recording sheet by Meyer bar coating to have a dry thickness of 4 μm. To obtain a heat-sensitive transfer image recording sheet. Saturated polyester (Toyo Byron 200Tg 67 ° C) 5.3 parts by weight (Toyo Byron 290Tg 77 ° C) 5.3 parts by weight VINYLITE VYHH (union carbide vinyl chloride / vinyl acetate copolymer) 4.5 parts by weight Titanium oxide (Titanium Industry Co., Ltd.) KA-10) 1.5 parts by weight Amino-modified silicone oil (KF-393 manufactured by Shin-Etsu Silicon) 1.1 parts by weight Epoxy-modified silicone oil (X-22-343 manufactured by Shin-Etsu Silicon) 1.1 parts by weight Toluene 30 parts by weight Methyl ethyl ketone 30 parts by weight Cyclohexanone 22 parts by weight Evaluation The curl height, surface roughness due to blocking, and gradation of the thermal transfer image recording sheet were evaluated according to the above evaluation methods. The results are shown in Table 1.

(Examples 2 to 5) As petroleum resins, "Arcon" P-140 (softening temperature 140 ° C) manufactured by Arakawa Chemical Co., Ltd., Escorets E5320 (softening temperature 12) manufactured by Tonex Co., Ltd.
0 ° C), Yasuhara Chemical Co., Ltd. "Clearon" P-12
A thermal transfer image recording sheet was obtained in the same manner as in Example 1 except that 5 (softening temperature 125 ° C.) was used. Then, according to the above evaluation method, curl height, surface roughness due to blocking, and gradation were evaluated. The results are shown in Table 1. (Example 6) A thermal transfer image recording sheet was obtained in the same manner as in Example 1 except that talc was used as the inorganic filler. Then, according to the above evaluation method, curl height, surface roughness due to blocking, and gradation were evaluated. The results are shown in Table 1.

(Examples 7, 11 to 12 and Comparative Examples 1 and 3)
5) A thermal transfer image recording sheet was obtained in the same manner except that the composition of each layer in Example 1 was changed to the composition shown in Table 1. Then, according to the above evaluation method, curl height, surface roughness due to blocking, and gradation were evaluated. The results are shown in Table 1. (Examples 8 to 9 and Comparative Example 2) Thermal transfer was performed in the same manner as in Example 1 except that the opening degree of the die for forming the layers (A), (B) and (C) described in Example 1 was changed. An image recording sheet was obtained. Then, according to the above evaluation method, curl height, surface roughness due to blocking, and gradation were evaluated. The results are shown in Table 1.

(Example 10) (1) Melt flow rate (MFR) was 0.8 g / 1.
55% by weight of polypropylene in 0 minutes has an average particle size of 1.5
After melt-kneading 15% by weight of ground calcium carbonate of 30 μm and 30% by weight of “Arcon” P-125 (softening temperature 125 ° C.) manufactured by Arakawa Chemical Co., Ltd. in an extruder set at a temperature of 270 ° C. Extruded into a sheet with a die,
It cooled by the cooling device and the non-stretched sheet was obtained. Then
After heating this sheet to a temperature of 150 ° C.,
It was stretched twice to obtain a 5 times stretched sheet for the base material layer (B). (2) 55% by weight of polypropylene with MFR of 4.0
A mixture of 45% by weight of ground calcium carbonate having an average particle size of 1.5 μm is melt-kneaded by an extruder set at a temperature of 220 ° C., then extruded into a sheet by a die and uniaxially stretched. The front surface layer (A) was prepared and laminated on one side of the uniaxially stretched substrate layer (B) (1). Next, this laminated sheet was cooled to a temperature of 60 ° C., then heated to a temperature of 162 ° C., stretched to 7.5 times in the transverse direction with a tenter, and then annealed at a temperature of 167 ° C. to 60 ° C. After cooling to a temperature of 3, the ears were slit to obtain a support for a thermal transfer image recording sheet (thickness of A / B is 15 μm / 135 μm) having a three-layer structure.

Preparation of Coating Solution for Thermal Transfer Image Receiving Layer A thermal transfer image receiving layer was coated on the surface of this support for thermal transfer image recording sheet in the same manner as in Example 1 to obtain a thermal transfer image recording sheet. . Then, according to the above evaluation method, curl height, surface roughness due to blocking, and gradation were evaluated. The results are shown in Table 1. Example 13 Production of Support Layer for Thermal Transfer Image Recording Sheet (1) Melt Flow Rate (MFR) 0.8 g / 1
85% by weight of polypropylene in 0 minutes has an average particle size of 1.5
2 μm containing 15% by weight of μm heavy calcium carbonate
After melt-kneading with an extruder set to a temperature of 70 ° C.,
It was extruded into a sheet by a die and cooled by a cooling device to obtain an unstretched sheet.

Next, this sheet was heated to a temperature of 150 ° C. and then stretched 5 times in the longitudinal direction to obtain a 5 times stretched sheet for the base material layer (B). (2) Polypropylene 5 with MFR of 4.0 g / 10 min
3. Composition (A ₁ ) in which 5% by weight of 45% by weight of ground calcium carbonate having an average particle size of 1.5 μm is mixed, and MFR of 4.
To 30% by weight of polypropylene of 0 g / 10 minutes, 40% by weight of heavy calcium carbonate having an average particle size of 1.5 μm and 30% by weight of “Arcon” P-125 (softening temperature 125 ° C.) manufactured by Arakawa Chemical Co., Ltd. as a petroleum resin. The compounded composition (A ₂ ) is melted and kneaded at a temperature of 220 ° C. in separate extruders, then fed to one coextrusion die, melt-laminated in the die, and then formed into a sheet by the die. extrusion, surface layer before the uniaxially stretched (a ₁ / a ₂₎ was prepared, which a ₁
Was laminated on one surface of the uniaxially-stretched base material layer (B) described above (1) so that the layer of FIG. On the other side, M
A mixture of 55% by weight of polypropylene having an FR of 4.0 and 45% by weight of ground calcium carbonate having an average particle size of 1.5 μm was melt-kneaded by an extruder set at a temperature of 220 ° C., and then sheeted by a die. To prepare a back surface layer (C) before being uniaxially stretched and laminated on the back surface side of the uniaxially stretched base material layer (B) (1). Then
After cooling this laminated sheet to a temperature of 60 ° C., 16
After heating to a temperature of 2 ° C, it was stretched to 7.5 times in the transverse direction with a tenter, then annealed at a temperature of 167 ° C, cooled to a temperature of 60 ° C, and the ears were slit to form a three-layer structure. Thermal transfer image recording sheet support (A ₁ / A ₂
The thickness of / B / C is 15μm / 25μm / 70μm / 40
μm) was obtained.

Preparation of Coating Solution for Thermal Transfer Receiving Layer A thermal transfer image receiving layer was coated on the (A ₁ ) layer side of the support for thermal transfer recording sheet in the same manner as in Example 1 to obtain a thermal transfer image recording sheet. It was And according to the above evaluation method,
The curl height, surface roughness due to blocking, and gradation were evaluated. The results are shown in Table 1. (Example 14) A thermal transfer image recording sheet was obtained in the same manner as in Example 11 except that the composition of the base material layer (B) was changed to the composition shown in Table 1. Then, according to the above evaluation method, curl height, surface roughness due to blocking, and gradation were evaluated. The results are shown in Table 1. (Example 15) A thermal transfer image recording sheet was obtained in the same manner as in Example 11 except that the compositions of the base material layer (B) and the back surface layer (C) were changed to those shown in Table 1. Wall thickness A ₁ / A ₂ / B / A ₂ / A ₁ = 15/25/70/2
5/15 μm). Then, according to the above evaluation method, curl height, surface roughness due to blocking, and gradation were evaluated. The results are shown in Table 1.

(Example 16) Production of thermal transfer image recording sheet (1) Melt flow rate (MFR) was 0.8 g / 1.
85% by weight of polypropylene in 0 minutes has an average particle size of 1.5
20% by weight of composition (A) containing 20% by weight of heavy calcium carbonate having a particle diameter of 1.5 μm, 20% by weight of heavy calcium carbonate having an average particle diameter of 1.5 μm, and 50% by weight of polypropylene having an MFR of 0.8 g / 10 min. The composition (B) in which 30% by weight of “ALCON” P-125 (softening temperature 125 ° C.) manufactured by Arakawa Chemical Co., Ltd. as a petroleum resin was blended was used in separate extruders.
After melt-kneading at a temperature of 0 ° C., the mixture was supplied to one coextrusion die, melt-laminated in the die, extruded at a temperature of 250 ° C., and cooled to a temperature of about 60 ° C. by a cooling roll. After heating this laminate again to 145 ° C., it was stretched 5 times in the machine direction by utilizing the peripheral speed difference of a large number of roll groups,
After heating again to a temperature of about 162 ° C., a tenter was used to draw 8.5 times in the transverse direction at a temperature of 162 ° C.
Annealed at a temperature of ℃, cooled to a temperature of 60 ℃, then slit the ears, double layer structure (A / B = 1
A support for a thermal transfer image recording sheet having a thickness of 5 μm / 130 μm) was obtained.

Preparation of Coating Solution for Thermal Transfer Image Receiving Layer A thermal transfer image receiving layer was coated on the (A) layer side of the support for this thermal transfer image recording sheet in the same manner as in Example 1 to prepare a thermal transfer image recording sheet. Got Evaluation The curl height, surface roughness due to blocking, and gradation were evaluated according to the above evaluation method. The results are shown in Table 2. (Examples 17 and 18) Thermal transfer image recording sheets were obtained in the same manner as in Example 13 except that the number of revolutions of the screw of the extruder for the compositions (A) and (B) was changed. Then, according to the above evaluation method, curl height, surface roughness due to blocking, and gradation were evaluated. The results are shown in Table 2.
Shown in.

(Example 19) Production of thermal transfer image recording sheet (1) Melt flow rate (MFR) was 0.8 g / 1.
80% by weight polypropylene in 0 minutes has an average particle size of 1.5
20% by weight of composition (A) containing 20% by weight of heavy calcium carbonate having a particle diameter of 1.5 μm, 20% by weight of heavy calcium carbonate having an average particle diameter of 1.5 μm, and 50% by weight of polypropylene having an MFR of 0.8 g / 10 min. Arakawa Chemical Co., Ltd. "Arcon" P-125 (softening temperature 125 ° C.) as a petroleum resin (30% by weight) was added to the composition (B), and MFR was 0.8 g / 10 min. The composition (C) containing 20% by weight of heavy calcium carbonate of 1.5 μm is melt-kneaded at a temperature of 270 ° C. by a separate extruder, and then supplied to one co-extrusion die, It was melt-laminated with, was extruded at a temperature of 250 ° C., and cooled to a temperature of about 60 ° C. with a cooling roll. After heating this laminate again to 145 ° C., it was stretched 5 times in the machine direction by utilizing the peripheral speed difference of a large number of roll groups, heated again to a temperature of about 162 ° C., and then 162 ° C. using a tenter. The film was stretched 8.5 times in the transverse direction at a temperature of 6 ° C., annealed at a temperature of 165 ° C., cooled to a temperature of 60 ° C., and then the ears were slit to form a three-layer structure (A / B / C = 15 μm / 120 μm
/ 15 μm) to obtain a support for a thermal transfer image recording sheet.

Preparation of Coating Liquid for Thermal Transfer Image Receiving Layer A thermal transfer image layer was coated on the (A) layer side of this thermal transfer image recording sheet support in the same manner as in Example 1 to form a thermal transfer image recording sheet. Obtained. Evaluation The curl height, surface roughness due to blocking, and gradation were evaluated according to the above evaluation method. The results are shown in Table 2. (Examples 20 to 21 and Comparative Example 7) Thermal transfer image recording sheets were obtained in the same manner as in Example 16 except that the composition of each layer was changed to the composition shown in Table 2. Then, according to the above evaluation method, curl height, surface roughness due to blocking,
Gradation was evaluated. The results are shown in Table 2.

Comparative Example 6 Production of Support Layer for Thermal Transfer Image Recording Sheet (1) Melt Flow Rate (MFR) 0.8 g / 1
50% by weight polypropylene in 0 minutes has an average particle size of 1.5
A mixture of 20% by weight of heavy calcium carbonate of 30 μm and 30% by weight of petroleum resin “Alcon” P-125 (softening temperature 125 ° C.) manufactured by Arakawa Chemical Co., Ltd.
After melt-kneading with an extruder set to a temperature of ℃, extruded into a sheet by a die and cooled by a cooling device to obtain an unstretched sheet. Next, this sheet was heated to a temperature of 150 ° C., stretched 5 times in the longitudinal direction, heated again to a temperature of 162 ° C., and then stretched 7.5 times in the transverse direction at a temperature of 162 ° C. using a tenter. did. After that, an annealing treatment was performed at a temperature of 167 ° C., and after cooling to a temperature of 60 ° C., the ears were slit to obtain a support for a thermal transfer image recording sheet having a thickness of 150 μm.

Preparation of Coating Solution for Thermal Transfer Image Receiving Layer A thermal transfer image receiving layer was coated on the surface of the support for thermal transfer image recording sheet in the same manner as in Example 1 to obtain a thermal transfer image recording sheet. . Evaluation The curl height, surface roughness due to blocking, and gradation were evaluated according to the above evaluation method. The results are shown in Table 2. (Example 8) A thermal transfer image recording sheet was obtained in the same manner as in Comparative Example 7 except that the composition of each layer was changed to the composition shown in Table 2. Then, according to the above evaluation method, the curl height,
Surface roughness due to blocking and gradation were evaluated. The results are shown in Table 2.

Example 22 Production of Support for Thermal Transfer Image Recording Sheet A base material layer obtained in the same manner as in Comparative Example 6 except that the opening degree of the die was changed so that the thickness was 130 μm ( B)
On the surface of, as a surface layer (A), a biaxially stretched film of polypropylene having a thickness of 20 μm (trade name, Sun Orient PB-262, manufactured by Nimura Chemical Co., Ltd.) was used with an adhesive (A / B). A support for a thermal transfer image recording sheet having a structure was obtained, and a thermal transfer image receiving layer was applied to the layer (A) side in the same manner as in Example 1 to obtain a thermal transfer image recording sheet. Evaluation The curl height of the thermal transfer image recording sheet, surface roughness due to blocking, and gradation were evaluated. The results are shown in Table 2.

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

EFFECT OF THE INVENTION A heat-sensitive transfer image recording sheet using such a heat-sensitive transfer image recording sheet support of the present invention is excellent in surface smoothness and has a cushioning property due to a large number of microvoids contained in the support. Excellent, which improves the adhesion between the head (die) and the thermal transfer image recording sheet, gives a transfer image with rich gradation, does not curl even after printing, and does not cause surface roughness due to blocking. , A heat-sensitive transfer image recording sheet.

[Brief description of drawings]

FIG. 1 is a schematic explanatory cross-sectional view of thermal transfer type thermal recording in which a support for a thermal transfer recording sheet is sandwiched by a print head and a drum.

FIG. 2 is a sectional view of a heat-sensitive transfer image recording sheet obtained by the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermal transfer member 2 Thermal transfer image recording sheet 3 Die 4 Substrate 5 Color material layer 6 Image receiving layer 7 Support 8 Drum 9 Base material layer 10 Surface layer

Claims (2)

[Claims] 1. A surface of a thermoplastic resin film (B) containing 3 to 60% by weight of petroleum resin, and 3% by weight of petroleum resin.
Surface layer (A) of a support having a structure in which a surface layer (A) made of a thermoplastic resin film containing less than
A thermal transfer image recording sheet having a thermal transfer image receiving layer formed thereon. 2. The surface layer (A) of the support has a wall thickness of 50.
The heat-sensitive transfer image recording sheet according to claim 1, having a thickness of not more than μm.