JPH10287057A - Transparent image receiving sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent image receiving sheet having satisfactory transferability of ink to be transferred, dot reproducibility, excellent gradability and image fixability. SOLUTION: The image receiving sheet comprises an at least uniaxially oriented transparent plastic film as a base material. An image receiving layer is provided at least on one surface of the film via part containing polyester and/or polyurethane as main components. A melting initiating temperature of a surface of the layer is 50 to 120 deg.C, surface wet tension is 30 to 40 mN/m, and haze as the sheet is 5% or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent image receiving sheet for use in an overhead projector (hereinafter abbreviated as "OHP"). The present invention relates to an image receiving sheet having excellent image reproducibility, particularly dot reproducibility and image reproducibility in a low density recording portion, and having excellent image fixing properties and high transparency.

[0002]

2. Description of the Related Art In recent years, attention has been focused on non-impact, easy-to-operate, easy-to-maintain, low-cost, and miniaturizable thermal transfer recording as one of recording methods in hard copy technology.

[0003] In particular, in a fusion type thermal transfer recording system,
Attention has been paid to a printing method for obtaining high gradation by printing the molten ink by partial transfer or by changing the dot diameter.

Conventionally, a transparent polyester film or the like has been used as a transparent image-receiving sheet for melt-type thermal transfer recording, and a vinylpyrrolidone / vinyl acetate copolymer is formed on the polyester film for the purpose of further improving the transferability of the molten ink. Lamination (Japanese Patent Application Laid-Open No. 62-231791), vinyl alcohol / vinyl acetate copolymer lamination (Japanese Patent Application Laid-Open No. 622-2)
No. 31792) and a copolymerized polyester laminate (Japanese Patent Application Laid-Open No. 4-86293) are known.

[0005]

However, in the fusion-type thermal transfer method for expressing high gradation, the amount of ink to be transferred is adjusted by controlling the energy applied to the thermal head, so that the minute dots corresponding to the transfer amount are controlled. The transferability to the image receiving sheet, that is, the dot reproducibility, and the transferability are particularly required when printing with a small energy, especially when printing with small energy.

In this respect, the polyester film conventionally used has a smooth surface, but has a high degree of crystal orientation, and therefore has poor dot transferability. Further, with the above-mentioned prior art in which a coating layer is provided on the surface for the purpose of improving this, it was not possible to obtain sufficient gradation.

[0007] The present invention improves the above disadvantages and provides a transparent image-receiving sheet which is excellent in transferability of ink to be transferred, excellent in dot reproducibility, excellent in gradation, and excellent in image fixability. Things.

[0008]

According to the present invention, there is provided a transparent image-receiving sheet for receiving an ink which is melted by heating, wherein the image-receiving sheet is based on a transparent plastic film stretched at least uniaxially, and at least one side of the transparent plastic film. The layer having polyester and / or polyurethane as a main component is interposed therebetween, and the surface of the image receiving layer has a melting start temperature of 50 to 120 ° C.
The present invention relates to a transparent image receiving sheet having a surface wetting tension of 30 to 40 mN / m and a haze of 5% or less as an image receiving sheet.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION As the base film in the present invention, typical ones are polyester films, polypropylene, polyolefin films such as polyethylene, polyamide films such as nylon, polyvinyl chloride films, polyurethane films, polycarbonate films. , An acrylic film, a fluorine film, or the like. These may be homopolymers or copolymers. Of these, polyester films are preferred in terms of mechanical strength, dimensional stability, adhesiveness to an image receiving layer, and the like.

The term "polyester film" is a generic term for a polymer film having an ester bond as a main bonding chain. Particularly preferred polyester films are polyethylene terephthalate film, polyethylene-2, and polyethylene-2.
6-naphthalate film, polyethylene-α, β-bis (2-chlorophenoxy) -ethane 4,4′-dicarboxylate film, polybutylene terephthalate film, polybutylene-2,6-naphthalate film and the like. Among these, dimensional stability, mechanical strength,
When the quality such as workability or the economic efficiency is comprehensively determined, polyethylene terephthalate film and polyethylene-2,6-naphthalate film are preferable. The polyester film may be a homopolymer, a mixture of these polyesters, or a part of another dicarboxylic acid component or diol component, preferably 20 parts.
Mole% or less may be copolymerized. Specific examples of the copolymerization component include isophthalic acid, aliphatic dicarboxylic acids having 4 to 10 carbon atoms, alicyclic dicarboxylic acids and esters thereof, diols having 3 to 20 carbon atoms, and cyclohexane dimethanol.

In the polyester film, other kinds of polymers may be blended or copolymerized within a range not to impair the object of the present invention, and various additives such as an antioxidant, a heat stabilizer, A weather stabilizer, an ultraviolet absorber, an organic lubricant, a pigment, a dye, organic or inorganic fine particles, a filler, an antistatic agent, a nucleating agent, and the like may be added.

The intrinsic viscosity of the above-mentioned polyester (25 ° C.)
Measured in o-chlorophenol) is 0.4-1.2.
dl / g is preferable, and more preferably 0.5 to 0.8 d
Those in the range of 1 / g are suitable for practicing the present invention.

The thickness of the base film is not particularly limited and is appropriately selected depending on the application. However, from the viewpoint of mechanical strength and the like, the thickness is usually 20 to 500 μm, preferably 50 to 500 μm.
３００300 μm. In addition, the obtained film may be laminated by various methods to form a thicker film,
When used for OHP or the like, a sheet which can be peeled off may be laminated on the surface opposite to the surface on which the image receiving layer is provided for the purpose of improving the printing running property.

According to the present invention, in forming the image receiving layer, a portion containing polyester and / or polyurethane as a main component is interposed on the base film, the melting start temperature of the surface of the image receiving layer is 50 to 120 ° C., and the surface is wetted. Tension is 30-40mN /
m. By providing a portion containing polyester and / or polyurethane as the main component on the base film, when an image is formed on the image receiving sheet by thermal transfer, the image fixability with the base film is improved, and a low density recording portion is formed. , The image reproducibility and the dot reproducibility are further improved.

As a method for providing the portion, a method (A) of co-extrusion in the process of melt-forming a base film, for example, a polyester film, or a method of applying and drying polyester and / or polyurethane on the base film ( B), a method of applying and drying a coating liquid in which a composition incompatible with the polyester and / or polyurethane and having a lower surface wetting tension is mixed and dried. The difference in the surface wetting tension is preferably at least 3 mN / m, more preferably at least 5 mN / m lower than polyester or polyurethane. In particular, the method of mixing, coating and drying (C) is a preferable method since the surface of the image receiving layer specified in the present invention can be formed at a stroke.

In this case, a portion mainly composed of polyester and / or polyurethane is formed on the base film side, and the surface, ie, the image receiving layer surface side, is covered with the incompatible composition. It is preferable that a mixed layer of both is formed.

Of the above methods, the former two methods (A,
When a layer of polyester and / or polyurethane is provided in B), the melting start temperature is further set on the layer.
A layer having a surface wetting tension of 30 to 40 mN / m at 120 ° C. is applied or formed by a method such as extrusion lamination or dry lamination.

When the polyester and / or polyurethane is provided by coating, it is coated on the base film,
Either drying (off-line coating) or coating in the substrate film forming step (in-line coating) may be used, but the latter method is preferable because it adheres firmly to the substrate (of course, the method (C) is also offline) Coating or in-line coating may be used). As the polyester and / or polyurethane to be used, conventionally known polyesters dissolved or dispersed in an organic solvent or water can be arbitrarily used.

Here, polyester is a generic term for polymers having an ester bond composed of a dicarboxylic acid component and a diol component as a main bonding chain of a main chain. Preferred polyesters include terephthalic acid and isophthalic acid as dicarboxylic acid components. , Naphthalenedicarboxylic acid, diphenyl ether-4,4-dicarboxylic acid, 5-sodium sulfo-
Isophthalic acid, glutaric acid, adipic acid, sebacic acid,
Trimellitic acid, azelaic acid, oxalic acid, succinic acid,
Or an ester-forming derivative thereof, and the addition of alkylene glycols such as ethylene glycol, propylene glycol, triethylene glycol, tetraethylene glycol, butanediol, diethylene glycol, neopentyl glycol, cyclohexanedimethanol, and bisphenol A-ethylene oxide as diol components. Or one or more selected from 2,2-bis (4-hydroxyphenyl) propane and the like. Specifically, a dicarboxylic acid component such as terephthalic acid, isophthalic acid, 5-sodium sulfo-isophthalic acid, adipic acid, sebacic acid, trimellitic acid, azelaic acid or an ester-forming derivative thereof, ethylene glycol, propylene glycol, Copolymerized polyesters selected from diol components which are alkylene glycols such as ethylene glycol, diethylene glycol and neopentyl glycol are preferably used.

In particular, it is preferable that the polyester contains a polyalkylene glycol and the glass transition point is 50 ° C. or lower, more preferably 30 ° C. or lower, and further preferably 10 ° C. or lower. The polyalkylene glycol is not particularly limited, but a homopolymer such as polyethylene glycol, polypropylene glycol, polytriethylene glycol, polytetramethylene glycol, polyethylene propylene glycol, or a copolymer of two or more thereof is preferably used. Further, the molecular weight of the polyalkylene glycol is 500 to 15,000, more preferably 800 to
Most preferably, it is 10,000, more preferably 1000-7000. Furthermore, the content of the polyalkylene glycol is preferably 0.5 to 100 parts by weight, more preferably 5 to 100 parts by weight, based on 100 parts by weight of the polyester component excluding the polyalkylene glycol in the polyester.
Most preferably, it is 70 parts by weight, more preferably 10 to 50 parts by weight.

Various polyurethanes can be used. Typical examples thereof include polyester urethane, polyether urethane, and polycarbonate urethane, and any polyurethane having a so-called main chain or a side chain having a urethane bond can be used. It is not particularly limited,
Any of those soluble in an organic solvent and those dissolved or dispersed in water can be arbitrarily selected. Of course, the thermoplastic polyurethanes used for the melt extrusion and extrusion lamination described above can also be suitably used.

Next, in the present invention, the melting start temperature of the surface of the image receiving layer must be 50 to 120 ° C., more preferably 60 to 100 ° C., and most preferably 70 to 9 ° C.
0 ° C. When the melting start temperature is lower than 50 ° C., the dot reproducibility is lowered due to overtransfer of the ink, or the surface of the image receiving layer of the image receiving sheet becomes sticky, and a part of the image receiving layer is removed when the surface is rubbed with a finger or the like. Or the image receiving sheets may be stuck together. On the other hand, when the temperature exceeds 120 ° C., the transferability of the ink is poor, and a problem that desired dots cannot be transferred accurately occurs. That is, missing dots or a change in dot diameter may occur, or in extreme cases, dots may not be transferred and an image may not be expressed.

In the present invention, the surface wetting tension of the surface of the image receiving layer needs to be 30 to 40 mN / m, more preferably 32 to 38 mN / m. When the surface wetting tension is less than 30 mN / m and 40 mN
If it is larger than / m, the transferability of the ink is poor, and the chipping of the dots and the change in the dot diameter may occur. In an extreme case, the dots may not be transferred and the gradation may not be expressed.

Further, in the present invention, the haze as the image receiving sheet needs to be 5% or less. It is more preferably 3% or less, and most preferably 2% or less. If it is more than 5%, the transparency is poor and OHP
Therefore, it is difficult to obtain a clear image and sufficient contrast when enlarged and projected, and the visibility of the image tends to be poor.

The composition for forming the surface of the image receiving layer is not particularly limited as long as it satisfies the above-mentioned requirements. For example, polyolefin, modified polyolefin, wax, acrylic resin, vinyl acetate resin, vinyl chloride resin, vinylidene chloride resin Thermoplastic resins such as styrene resin, nylon resin, polyether resin, silicone resin, urea resin, and phenol resin can be used. These thermoplastic resins may be used alone, or two or more kinds thereof may be mixed and / or copolymerized. Among these thermoplastic resins, those containing polyolefin, modified polyolefin or wax as a main component are preferable in view of the melting initiation temperature and the surface wetting tension of the image receiving layer surface, and furthermore, in view of image reproducibility and dot reproducibility. Modified polyolefins are particularly preferred.

The above-mentioned polyolefins are polymers of olefins represented by ethylene, propylene and ethylene-propylene, and the modified polyolefins are urethanes, acrylic acid, methacrylic acid and their esters, polyesters, It is a copolymer with paraffin, vinyl acetate, vinyl chloride, styrene, butadiene and the like. Examples of the modified polyolefin include urethane-modified polyethylene, acrylic acid-modified polyethylene, paraffin-modified polyethylene, ethylene-vinyl acetate copolymer, ethylene-vinyl chloride copolymer, ethylene-acrylic acid copolymer, ethylene-styrene copolymer Such as 2
Terpolymers such as ethylene copolymer, ethylene-acrylic acid-vinyl acetate copolymer, ethylene-vinyl acetate-vinyl chloride copolymer, ethylene-acrylic acid-styrene copolymer, ethylene-butadiene-styrene copolymer A polymer or the like can be used, but all of them are limited to those satisfying the above requirements.

Of these, urethane-modified polyethylene and acrylic acid-modified polyethylene can be particularly preferably used.

In the case where the image receiving layer is provided at once in the film production process, it is preferable to select a composition which follows the stretching of the base film or a composition which is melted and smoothed by heat treatment.

Further, in the image receiving layer, various additives such as an antistatic agent, an antioxidant, a heat stabilizer, a weather stabilizer, an ultraviolet absorber, an organic and / or an organic compound are added as long as the effects of the present invention are not impaired. Or inorganic fine particles, organic lubricants, pigments,
A dye, a filler, a nucleating agent, a crosslinking agent, and the like may be blended.

Further, in the present invention, when the image receiving layer is provided on one side of the base film, the surface specific resistance of the transparent image receiving sheet opposite to the image receiving layer is 10 ¹² Ω / □ or less, more preferably 10 ¹² Ω / □. It is more preferably ¹¹ Ω / □ or less, more preferably 10 ¹⁰ Ω / □ or less, from the viewpoints of sheet transportability, paper feedability, and prevention of adhesion of dust. The method for obtaining the above-mentioned surface specific resistance is not particularly limited, but usually, a method of applying an antistatic agent to the surface of the transparent plastic film as a base material or adding the antistatic agent into the transparent plastic film is employed. The antistatic agent is not particularly limited. For example, ionic polymers, surfactants, conductive inorganic fine particles, inorganic electrolytes, organic complex salts, and the like can be used.

The ionic polymer is a generic term for polymers having an ionic group as a main chain, a side chain or a pendant of the main chain. Examples of the ionic group include sulfonic acid salts,
Anionic groups such as carboxylate, phosphate, alkylsulfonate and alkylphosphate ester salts; cationic groups such as alkyltrimethylammonium salt, lauryltrimethylammonium chloride and alkylpyrrolidium salt; alkylbetaine type; alkylimidazoline And zwitterionic groups such as alkylalanine type.

Examples of the surfactant include anionic surfactants such as alkyl sulfonates, alkylbenzene sulfonates and alkyl phosphates, and cationic surfactants such as quaternary ammonium chloride and quaternary ammonium sulfate. Surfactants, polyethers, polyhydric alcohols, polyoxyethylene alkylamines, nonionic surfactants such as polyoxyethylene fatty acid esters, alkyl betaine type, alkyl imidazoline type,
Amphoteric surfactants such as alkylalanine type, fluorine type surfactants, or polyvinylbenzyl type cations,
A conductive resin such as a polyacrylic acid type cation can be used.

Of these, ionic polymers are preferred from the viewpoints of coatability, miscibility with other compositions, and the like. The ionic polymer is a general term for polymers having an ionic group as a main chain, a side chain or a pendant of the main chain, and specific examples thereof include a polymer having an ionic group in the main chain such as a pyrrolidium ring. , A polymer having a piperidinium ring or the like in its main chain, or a polymer containing a compound having an unsaturated bond to these compounds as a copolymer component.

As the polymer having an ionic group in the side chain, for example, a homopolymer of acrylic acid, methacrylic acid, styrene and the like and / or other components such as saturated hydrocarbons such as polyethylene and polypropylene, polyacetylene and the like Those having a main chain of a copolymer such as an unsaturated hydrocarbon or an alkylene oxide and having an ionic group in a side chain such as a phosphate, a sulfonate, a vinyl sulfonate, and a carboxylate can be used.

In carrying out the present invention, the coating method of the image-receiving layer forming coating solution includes, for example, a reverse coating method, a gravure coating method, a knife coating method, a roll coating method, a blade coating method, a bead coating method, a rotating screen coating method, and a slot coating method. Orifice coating, rod coating, bar coating, die coating, spray coating and the like can be used.

The coating step may be any of a method of coating and drying on a base film (off-line coating) and a method of coating in a base film forming step (in-line coating). That is, the method using in-line coating is preferred from the viewpoint of uniformity of the image receiving layer, thin film coating, and economy.

Although the thickness of the image receiving layer is not particularly limited, it is usually preferably 0.01 to 5 μm, more preferably 0.05 μm.
2 to 2 μm. If it is smaller than 0.01 μm, the transferability of the ink may be poor. On the other hand, if it is larger than 5 μm, the transparency of the image receiving layer is reduced, and consequently the transparency of the image receiving sheet is reduced, and the visibility of the image tends to be poor.

Next, an example of the method for producing the transparent image-receiving sheet of the present invention will be described, but the present invention is not limited thereto.

Polyethylene terephthalate (hereinafter abbreviated as PET) pellets (intrinsic viscosity 0.5 to 0.8 dl / g) containing 0.001 to 0.1% by weight of inorganic particles having an average particle size of 0.01 to 10 μm are prepared. After vacuum drying,
It is supplied to an extruder, melted at 260 to 300 ° C., extruded into a sheet shape from a T-shaped die, wound around a mirror casting drum having a surface temperature of 10 to 60 ° C. using an electrostatic application casting method, and cooled and solidified. Create a stretched PET film. The unstretched film is rolled in a longitudinal direction (moving direction of the film) by 2.5-
Stretch 5 times. At least one surface of the film is subjected to a corona discharge treatment, and a coating liquid for forming an image receiving layer is applied to the treated surface. The coated film is gripped with a clip and
After being guided to a hot-air zone heated to 150 ° C. and dried, it is stretched 2.5 to 5 times in the width direction, and subsequently 160 to 2
It was led to a heat treatment zone of 50 ° C., and heat treatment was performed for 1 to 30 seconds to complete the crystal orientation. During this heat treatment step, a 3 to 12% relaxation treatment may be performed in the width direction or the longitudinal direction as necessary. Biaxial stretching may be any of longitudinal, horizontal sequential stretching or simultaneous biaxial stretching, and, after longitudinal and transverse stretching,
The film may be stretched in any of the vertical and horizontal directions. The coating solution for forming the image receiving layer used in this case is preferably water-based in view of environmental pollution and explosion-proof properties.

In addition to the above method, a coating liquid for forming an image receiving layer of the present invention is applied to a biaxially stretched transparent polyester film,
It can also be obtained by drying.

The thus-obtained transparent image-receiving sheet has good transferability of inks, particularly inks used for melt-type thermal transfer, and provides gradation, print density, image reproducibility, and especially dot reproducibility. It is excellent in image quality and image reproducibility in a low density recording portion, has excellent image fixing properties, and has high transparency.

[0042]

[Method for measuring characteristics and method for evaluating effects] The method for measuring characteristics and the method for evaluating effects in the present invention are as follows.

(1) Cross Section and Thickness of Image Receiving Layer Using a transmission electron microscope model HU-12 manufactured by Hitachi, Ltd., the cross section of the transparent image receiving sheet was determined from a photograph obtained by observation.
The thickness was an average value of 30 pieces in the measurement visual field.

(2) Surface wetting tension Measured according to JIS-K-6768. However, the measurement was performed at a measurement condition of 23 ° C. and a relative humidity of 65%.

(3) Melting Start Temperature The image-receiving sheet is cut into a size of 10 mm × 10 mm, and one cover glass manufactured by Matsunami Glass Industry Co., Ltd. is stacked from the image-receiving layer side so that the image-receiving sheet is almost at the center. In this state, using a melting point measuring device (manufactured by Yanagimoto Seisakusho), the temperature is increased stepwise from 40 ° C. to 5 ° C., and the temperature at which the image receiving layer melts when held at each temperature for 5 minutes is visually observed. Observation was made to be the melting start temperature of the surface of the image receiving layer.

(4) Haze Suga Test Machine Co., Ltd., fully automatic direct reading haze computer H
It measured using GM-2DP according to JIS-K-7015.

(5) Gradation As a color printer, "Professional
Color Point 2 "(manufactured by Seiko Denshi Kogyo Co., Ltd.), CH70 dedicated as a thermal transfer ink ribbon
Using 5 (yellow, magenta, cyan) manufactured by Seiko I Supply Co., Ltd., a 4-tone test pattern was printed on the transparent image receiving sheet of the present invention. Then, the gradation of the printed surface was visually determined, and the following three-stage evaluation was performed. ○
The above was regarded as good.

：: 4 gradations can be reproduced Δ: 3 or more gradations can be reproduced ×: No gradation

(6) Print Density and Image Reproducibility The state of the print surface printed by the method of (5) was visually observed for print density and image reproducibility, and the following four grades were evaluated.以上 The above was judged to be good.

：: Very good image with very high overall print density and no transfer unevenness 良好: Good image with high overall print density and almost no transfer unevenness, and good image reproducibility Good.

Δ: Transfer unevenness is observed and image reproducibility is poor. X: Transfer unevenness or untransferred portion is observed a lot, and image reproducibility is completely poor.

(7) Image Reproducibility of Low Density Recorded Part Of the print surface printed by the method of (5), the image reproducibility of the part having the lightest gradation is visually observed, and the following four grades are evaluated. went.以上 The above was judged to be good.

◎: No transfer unevenness at all, very good ：: Good image with slight transfer unevenness observed Δ: Many transfer unevenness observed, poor ×: Image not transferred

(8) Dot Reproducibility The magenta portion of the printing surface printed by the method (5) was observed at a magnification of 200 times using a transmission optical microscope, and the dot shape was evaluated in the following four steps. Was done.以上 The above was judged to be good.

◎: The dot shape is circular and extremely good. ：: Some dots are partially missing but good. Δ: Dots are missing. Or the dots are small or the dots are crushed. ×: The dots are remarkably missing. Or the dots are extremely small

(9) Image Fixing Property "S"
A "touch" mending tape (manufactured by Sumitomo 3M Ltd.) was adhered, and the image was observed visually for the persistence of the image after the T-shaped peeling.
The above was judged as good.

：: Image hardly transferred to mending tape △: Image partially peeled ×: Image peeled in plane

[0058]

Next, the present invention will be described with reference to examples, but is not necessarily limited thereto.

Example 1 0.015% by weight of silica particles having an average particle size of 0.4 μm
And PET pellets containing 0.005% by weight of silica particles having an average particle size of 1.5 μm (intrinsic viscosity 0.62 dl /
g) was sufficiently dried in vacuum, and then fed to an extruder at 285 ° C.
, And extruded into a sheet from a T-shaped die, wound around a mirror-surface casting drum having a surface temperature of 25 ° C. using an electrostatic application casting method, and cooled and solidified. This unstretched film is heated to 95 ° C. and stretched 3.2 times in the longitudinal direction,
This was a uniaxially stretched film. The film was subjected to corona discharge treatment in air, and the treated surface was coated with the following coating solution for forming an image receiving layer. The coated uniaxially stretched film is guided into a preheating zone while being gripped by clips, dried at 110 ° C., and then continuously continuously heated in a 125 ° C. heating zone at a width of 3.2.
Stretched twice and heat-treated in a heating zone at 230 ° C,
A transparent image-receiving sheet made of a PET film provided with an image-receiving layer whose crystal orientation was completed was obtained. About the obtained transparent image-receiving sheet, the thickness of the base PET film is 75 μm, the thickness of the image-receiving layer is 0.08 μm, the haze as the image-receiving sheet is 1.6%, the melting start temperature of the image-receiving layer surface is 75 ° C., and the surface is wet. The tension was 36 mN / m. Table 1 shows the evaluation results.

"Coating solution for forming image-receiving layer" (A) Modified polyolefin: urethane-modified polyethylene aqueous dispersion (urethane-modified ratio = 20% by weight, emulsified by heating in an aqueous ammonia solution to form an aqueous dispersion) B) Polyester: polyethylene glycol (hereinafter, referred to as “polyethylene glycol”)
Aqueous dispersion of copolyester (abbreviated as PEG) (terephthalic acid / isophthalic acid / 5-sodium sulfo-isophthalic acid / ethylene glycol / neopentyl glycol / PEG = 50/49/1/55 / 42.3 / 2.7)
(Molecular ratio), PEG molecular weight =
4000, PEG content = 30 parts by weight, glass transition point (hereinafter abbreviated as Tg) = − 16 ° C.) (A) / (B) were mixed at a solid content weight ratio of 50/50, and diluted with water. The solid content was adjusted to 3%.

Example 2 In Example 1, the modified polyolefin was converted into an acrylic acid-modified polyethylene aqueous dispersion (acrylic acid-modified ratio = 20% by weight, emulsified by heating in an aqueous ammonia solution to form an aqueous dispersion). Example 1 except for the change
A transparent image-receiving sheet was obtained in the same manner as described above. Table 1 shows the evaluation results.

Example 3 In the same manner as in Example 1, except that the modified polyolefin was changed to a water dispersion of polyethylene wax (a water dispersion obtained by emulsifying polyethylene wax by heating and pressurizing). Thus, a transparent image receiving sheet was obtained. Table 1 shows the evaluation results.

Comparative Example 1 A transparent image-receiving sheet was obtained in the same manner as in Example 2, except that the modified polyolefin was omitted. Table 1 shows the evaluation results.

Comparative Example 2 An image receiving sheet was obtained in the same manner as in Example 1 except that the polyester was omitted. Table 1 shows the evaluation results.
Shown in

Comparative Example 3 In Example 1, the modified polyolefin was changed to an aqueous dispersion of paraffin wax (a water dispersion obtained by adding a nonionic surfactant to paraffin wax, heating and pressurizing to emulsify). A transparent image-receiving sheet was obtained in the same manner as in Example 1 except for the above. Table 1 shows the evaluation results.

Comparative Example 4 A transparent image-receiving sheet was obtained in the same manner as in Example 1, except that the modified polyolefin was changed to an aqueous dispersion of oxidized wax. Table 1 shows the evaluation results.

Comparative Example 5 A transparent image-receiving sheet was obtained in the same manner as in Example 1, except that the modified polyolefin was changed to an aqueous dispersion of polypropylene wax. Table 1 shows the evaluation results.

Comparative Example 6 In Example 1, the modified polyolefin was obtained by dispersing an ethylene-vinyl acetate copolymer in water (vinyl acetate copolymerization ratio = 1).
A transparent image-receiving sheet was obtained in the same manner as in Example 1, except that 9% by weight of an ethylene-vinyl acetate copolymer was coarsely dispersed by a pin mill and then converted to an aqueous dispersion by a sand grinder. . Table 1 shows the evaluation results.

Examples 4 to 6 In Example 1, the solid content weight ratio of the modified polyolefin / polyester was 10/90, 30/70, 70/70, respectively.
A transparent image-receiving sheet was obtained in the same manner as in Example 1 except that it was changed to 30. Table 1 shows the evaluation results.

Examples 7 to 9 Transparent image receiving sheets were obtained in the same manner as in Example 1, except that the polyester was changed to that shown in Table 2. Table 1 shows the evaluation results.

Example 10 The same coating liquid for forming an image receiving layer as in Example 1 was applied on one side of a biaxially oriented transparent PET film ("Lumirror" T60 manufactured by Toray Industries, Inc.) having a thickness of 100 μm, and the thickness after drying was 0.1 μm. Was applied with a gravure coater and dried at 120 ° C. for 2 minutes to obtain a transparent image receiving sheet. Table 1 shows the evaluation results.

[0072]

[Table 1]

[Table 2]

[0073]

The transparent image-receiving sheet prepared according to the present invention is a transparent image-receiving sheet for receiving an ink melted by heating, wherein the image-receiving sheet comprises a transparent plastic film stretched at least uniaxially as a base material. The image receiving layer provided on at least one side of the film has a portion mainly composed of polyester and / or polyurethane interposed therebetween, and the surface of the image receiving layer has a melting start temperature of 50 to 120 ° C and a surface wetting tension of 30 to 40 mN /
m, and the haze as an image receiving sheet is 5% or less, and has good ink transferability, gradation, print density, image reproducibility, especially dot reproducibility. It is excellent in image reproducibility of a low density recording portion, excellent in image fixability, and has high transparency.

Claims (6)

[Claims] 1. A transparent image receiving sheet for receiving an ink melted by heating, wherein the image receiving sheet is a transparent plastic film stretched at least uniaxially as a base material,
The image receiving layer provided on at least one side of the transparent plastic film has a portion mainly composed of polyester and / or polyurethane interposed therebetween, and the surface of the image receiving layer has a melting start temperature of 50 to 120 ° C and a surface wetting tension of 30 to 120 ° C. 40
A transparent image receiving sheet having mN / m and a haze of 5% or less as an image receiving sheet. 2. The transparent image receiving sheet according to claim 1, wherein the transparent plastic film is a transparent polyester film. 3. The surface resistivity of the surface opposite to the image receiving layer is 10 ¹²
The transparent image-receiving sheet according to claim 1, wherein the value is Ω / □ or less. 4. The transparent image receiving sheet according to claim 1, wherein the polyester contains a polyalkylene glycol. 5. The transparent image receiving sheet according to claim 1, wherein the glass transition point of the polyester is 50 ° C. or lower. 6. The transparent image receiving sheet according to claim 1, wherein the transparent image receiving sheet is for an overhead projector.