JPH0820168A - Image-receiving sheet for thermal transfer - Google Patents

Abstract

(57) [Summary] [Purpose] To obtain an image-receiving sheet for thermal transfer, which has good curl balance, transportability in a printer, image bleeding resistance, and resistance to film cracking of a heat-resistant layer. [Structure] One side is coated with a polyolefin resin containing a specific amount of high-density polyethylene on one side of a base paper, a specific porous film is attached to the other side, and a heat-resistant layer made of a specific radiation-curable resin composition is further formed. An image-receiving sheet for heat-sensitive transfer, comprising the support provided and an image-receiving layer provided on the heat-resistant layer of the support.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a thermal printer,
The present invention relates to a heat-sensitive transfer image-receiving sheet used for recording by transferring a heat transferable dye in heat-sensitive transfer recording of a laser printer or the like.

[0002]

2. Description of the Related Art In recent years, as a means of color hard copy, a device using a thermal transfer recording system has been widely spread because of its advantages such as light weight, compact size, no noise, and excellent operability and maintainability. ing. This thermal transfer recording system is roughly classified into two types, which are a heat melting type and a heat transfer type or a sublimation type. In particular, the latter is excellent in reproducibility of multi-color gradation images and is printed using a sublimation type thermal transfer printer.

The principle of such a sublimation type thermal transfer type printer is that an image is converted into an electric signal and then this electric signal is converted into a heat signal by using an electric heating element such as a thermal head, or A transfer sheet coated with a heat transferable dye (hereinafter referred to as a dye) is heated by heating a light absorption heating element with a laser to convert it into a heat signal, and then sublimated or thermally diffused in a medium. By this, the dye transfers the dye from the transfer sheet to the image receiving layer of the heat-sensitive transfer image receiving sheet, thereby recording characters and image information.

The sublimation type thermal transfer recording system can obtain an image comparable to a multicolor printed matter or a color photograph. Further, it is less expensive than a printing technique or a photographic technique in an application in which the number of copies to be produced is small. It is being used.

Recently, the field of application of the sublimation type thermal transfer printer, which has been attracting a lot of attention, includes the production of color proofs in the printing field where high image quality close to that of a photograph is required and the output of design images in the design field. It is also practiced to output the characters and image information created in 1 above to a transparent recording sheet using a sublimation thermal transfer printer, and use this as an original for an overhead projector in a presentation at a conference. Furthermore, card printing systems such as ID cards, license cards, and management cards have been developed, and are responding to a wide range of card needs in the advanced information society.

In particular, in recent years, the demand for color hard copy has increased and it has become necessary to increase the printing speed.
Higher sensitivity is required so that a clear image can be obtained even when the applied energy is low. Higher sensitivity is achieved by reducing the applied energy loss by thinning the film support of the transfer sheet or by increasing the platen pressure in the printer drive section to improve the adhesion between the transfer sheet and the thermal transfer image-receiving sheet. It is known that this is achieved, but in particular, the adhesion between the transfer sheet and the image-receiving sheet for heat-sensitive transfer and the heat insulating property of the image-receiving sheet for heat-sensitive transfer have a great influence on the sensitivity, and therefore, for example, JP-A-63-290790. A synthetic resin film (in the present invention, referred to as a porous film) having a porous structure having excellent heat insulating properties and cushioning properties, as described in Japanese Patent Publication No. 63-231984 and Japanese Patent Publication No. 63-231984, is used as a support. Is effective.

However, such a synthetic resin film is
Generally, the printer is composed of a material having poor heat resistance such as polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer, and ethylene-vinyl alcohol copolymer. In addition to having the disadvantage that the dot reproducibility of the transferred image deteriorates because the support heat-shrinks due to the applied heat when printing with
In particular, when a film having a porous structure is used for the purpose of improving the heat insulating property and cushioning property for higher sensitivity, the smoothness of the surface is decreased, the glossiness is decreased, and the product quality is significantly decreased. To do. In particular, in the field of high-quality color images, silver salt photography has become widespread at present, and a high gloss level equivalent to that of silver salt photography is also required for a thermal transfer image-receiving sheet. It was difficult to achieve both high sensitivity and high gloss.

[0008]

Therefore, the present inventors have attached a synthetic resin film having a porous structure to at least one surface of a cellulose fiber paper or a synthetic resin film, and to the non-adhesive side of the synthetic resin film. It has been found that by providing a heat-resistant layer made of a radiation-curable resin, the above problems can be overcome, and at the same time, the resistance to image bleeding can be improved (JP-A-6-115269).

However, if a heat-resistant layer made of a radiation-curable resin is provided in order to improve heat resistance and image bleeding resistance, curing shrinkage of the heat-resistant layer is large and curling occurs on the image receiving layer side, so-called plus curl. The problem that the transferability of the heat-sensitive transfer image-receiving sheet in the printer deteriorates, jamming occurs in some cases, and the heat-resistant layer cracks when the heat-sensitive transfer image-receiving sheet is subjected to stress such as bending was there.

[0010] Therefore, the present invention maintains the high sensitivity, high gloss and resistance to image bleeding of the image-receiving sheet for thermal transfer, which the present inventors have previously invented and applied for, while maintaining resistance to film cracking and curling of the heat-resistant layer. It is an object of the present invention to improve the characteristics and provide a higher quality image-receiving sheet for thermal transfer.

[0011]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a resin coating layer made of a polyolefin resin containing a specific amount of high-density polyethylene on one side of a base paper. If a porous film is provided on the other side of the base paper and a heat-resistant layer made of a radiation curable resin composition that causes shrinkage on curing is provided on the non-adhesive side of the film, the curl of the entire support is curled. I have found that it can be suppressed. Further, by providing a radiation-curable resin having a specific acryloyl equivalent in a specific amount and providing a heat-resistant layer made of a radiation-curable resin composition having a specific average acryloyl equivalent, the resistance to image bleeding resistance is not reduced. It was found that the film cracking property can be improved.

That is, the image-receiving sheet for heat-sensitive transfer of the present invention comprises
An image-receiving sheet for heat-sensitive transfer comprising an image-receiving layer for receiving a heat-transferable dye from a thermal transfer medium on a support, wherein the support has a density of 0.95 g / cm ³ defined on JIS K6748 on one side of the base paper. 10 high density polyethylene resin
A resin coating layer made of a polyolefin resin containing 80% by weight to 80% by weight is provided, and a porous film having a density of 85% or less with respect to a non-porous film of the same material is attached to the other surface, and at least one or more Acryloyl equivalent 15
The support is provided with a heat-resistant layer comprising a radiation-curable resin composition having an average acryloyl equivalent of 100 to 190 and containing a radiation-curable resin of 0 to 280 in an amount of 10 to 50% by weight. An image receiving layer is provided.

Further, for coating a resin coating layer of a polyolefin resin or sticking a porous film to the base paper, a molten polyolefin resin is used as an adhesive and is applied or stuck by a polylamination method. It is preferable.

The thermal transfer image-receiving sheet of the present invention will be described in detail below. First, the structure of the heat-sensitive transfer image-receiving sheet of the present invention will be described with reference to FIG. Figure 1
1 is a cross-sectional view showing an image-receiving sheet for heat-sensitive transfer of the present invention, in which a resin coating layer 1 is provided on one side of a base paper 2, a porous film 3 is provided on the other side of the base paper 2, a heat-resistant layer 4 thereon, and an image receiving layer. 5
Is provided.

In the present invention, the base papers are NBKP and LB.
Wood pulp such as KP, NBSP, LBSP, GP, TMP, CGP and DIP, and synthetic pulp such as vinylon, polyester and polyethylene, and if necessary, filler, dye, sizing agent, dry paper strengthening agent, wet paper strengthening A chemical agent such as a fixing agent, a fixing agent, a conductive agent and a yield improving agent is added, and papermaking is carried out by a Fourdrinier paper machine, a twin wire paper machine, a hybrid paper machine, a round net paper machine, etc.
Base paper as described in Japanese Patent No. 10889 is preferable. Further, in order to improve the surface smoothness, the base paper is preferably calendered by a machine calender, a super calender, a thermal calender or the like.

The basis weight of the base paper in the present invention is not particularly limited, but is usually about 50 to 200 g / m ² . When the basis weight of the base paper is less than 50 g / m ² , the rigidity of the image-receiving sheet for thermal transfer is lowered, and bending is likely to occur in the conveyance guide of the printer. When it exceeds 200 g / m ² , the rigidity is increased. Is too high, and a defective biting easily occurs in the transport roll of the printer.

In the present invention, the polyolefin resin used for the resin coating layer provided on one surface of the raw paper is preferably a polyolefin resin which can be coated by a melt extrusion method, and is a homopolymer of α-olefin such as ethylene or propylene, and two or more kinds thereof. It is possible to use a copolymer composed of α-olefin, a copolymer of α-olefin as a main component with another monomer copolymerizable therewith, or a mixture thereof.

In order to suppress curling of the heat-sensitive transfer image-receiving sheet even if a heat-resistant layer made of a radiation-curable resin composition is provided, the polyolefin resin contains 10 to 80% by weight of a high-density polyethylene resin. And Here, if the high-density polyethylene resin is less than 10% by weight, it is difficult to suppress the positive curl due to curing shrinkage of the heat-resistant layer, and if it exceeds 80% by weight, the rigidity of the polyolefin resin coating layer becomes too high. , It may cause a negative curl.

High density polyethylene in the present invention means
It is a high-density polyethylene having a density of 0.95 g / cm ³ or more specified by JIS K6748. Here, the density is 0.
If it is less than 95 g / cm ³ , it becomes difficult to suppress the positive curl due to the curing shrinkage of the heat-resistant layer.

The method of providing the resin coating layer on one surface of the base paper is produced by a so-called melt extrusion method in which the resin melted by heating is cast on the running base paper. The thickness of the resin coating layer is 5
It is about 35 g / m ² .

The resin coating layer includes white pigments such as titanium dioxide, alumina, calcium carbonate, talc and zinc oxide,
Coloring pigments, fatty acid amides such as stearic acid amide and arachidic acid amide, zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, zinc barmitate, fatty acid metal salts such as zinc myristate, calcium barmitate, and hindered phenols. , Various stabilizers and antioxidants such as hindered amine, phosphorus-based and sulfur-based, blue pigments and dyes such as cobalt blue, ultramarine blue, cealine blue and phthalocyanine blue, optical brighteners, ultraviolet absorbers, dispersants and lubricants Various additives can be added.

On the resin coating layer side, printing for displaying the coated surface of the image receiving layer or displaying the manufacturer's logo may be performed.
As a printing method, a general printing method such as offset printing, gravure printing, flexo printing, screen printing can be used, and either single-color or multi-color printing may be used.

As the porous film used in the present invention, any one having good smoothness and heat insulating property can be preferably used, but from the viewpoint of material, for example, polyethylene, polypropylene, polyethylene terephthalate, poly Examples of the synthetic resin film include vinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer and polyamide.

Particularly, for the purpose of increasing the sensitivity, it is preferable that the density of the non-porous film made of the same material is 85% or less. The density of a normal non-porous film varies depending on the material, but is about 1.0 to 0.9 for polyolefins such as polyethylene and polypropylene, and about 1.4 for polyester.

As in the present invention, by using a porous film having a density of 85% or less of the density of the non-porous film, it is possible to print with high density even with a low heat energy. A specific example of the polyester film is Dia foil W900 manufactured by Dia foil Hoechst Co., Ltd. (a foamed white polyester film having a density of 1.0 g / cm ^{3 and} a density of a non-porous polyester film of 1.4).
In comparison with the polypropylene film, YUPO FPG manufactured by Oji Yuka Synthetic Paper Co., Ltd. (density about 0.
In 77g / cm ^3, 85 of non-porous polypropylene film
%) And TOYOPEARL manufactured by Toyobo Co., Ltd. (density of about 0.6 g / c
In m ^3, 66%) or the like of the non-porous polypropylene film.

The thickness of the porous film in the present invention is
It is preferably 20 to 60 μm. When the thickness of the film is less than 20 μm, the heat insulating property is lowered, so that the sensitivity is lowered, and when it exceeds 60 μm, the rigidity is lowered due to the limitation of the thickness of the support, and Bending is likely to occur in the transport guide.

In the present invention, the porous film needs to be firmly adhered to the surface of the base paper in order to suppress the occurrence of blisters during printing with a printer.
As a method for laminating the base paper and the porous film, a vinyl acetate type, a polyurethane type, a dry laminating method using an organic solvent solution such as an acrylic resin as an adhesive, an aqueous solution of starch, polyvinyl alcohol, casein or the like, a vinyl acetate type, Wet laminating method using emulsion of polyurethane type or acrylic type resin as adhesive agent, hot melt laminating method of melting wax type resin as adhesive agent, polylaminate using molten polyolefin type resin extruded from T die as adhesive agent There is a method such as a polylamination method, but in order to suppress curling of the image-receiving sheet for heat-sensitive transfer of the present invention, the polylamination method is particularly preferable because it can obtain appropriate rigidity.

The polyolefin resin used for the polylaminate is, for example, a homopolymer of α-olefin such as ethylene or propylene, or two or more types of α-olefin.
A copolymer consisting of an olefin, a copolymer of α-olefin as a main component and another monomer copolymerizable therewith,
And mixtures thereof can be used. As the coating weight of the polyolefin resin, preferably about 1 to 30 g / m ^2, not only the positive curl of the thermal transfer image-receiving sheet is less than 1 g / m ² can not be suppressed, the adhesive strength is insufficient blister If it exceeds 30 g / m ² , the rigidity becomes too large, the negative curl of the heat-sensitive transfer image-receiving sheet becomes strong, and jamming occurs in the printer or the handling property becomes poor.

On the other hand, the prior application of the present inventors (Japanese Patent Laid-Open No. 6-11
5269), when a heat-resistant layer made of a radiation-curable resin is provided on a synthetic resin film having a porous structure, a support having excellent heat resistance and high gloss is obtained. be able to. The thickness of the heat resistant layer is 1 to 25
About 1 μm or less is preferable, and if it is 1 μm or less, high gloss cannot be expected because it is applied on a synthetic resin film having originally a low smoothness porous structure, and if it is 25 μm or more, it is advantageous due to the porous structure of the synthetic resin film. It has been proved that a certain heat insulating property and cushioning property cannot be effectively utilized and the sensitivity is lowered.

Further, in the above-mentioned prior application by the present inventors, a heat-resistant layer is formed by using a compound containing an acryloyl group excellent in radiation curability in the molecule and having an acryloyl equivalent of 190 or less, thereby improving the resistance to heat. It is shown that an image-receiving sheet for heat-sensitive transfer excellent in image bleeding can be obtained. Here, the acryloyl equivalent is a numerical value obtained by dividing the molecular weight by the number of acryloyl groups in the molecule, and the smaller the numerical value, the higher the density of the photocrosslinking functional group.

However, the acryloyl equivalent is 190
In the heat-resistant layer composed of the following compounds, since the curing shrinkage is large, the heat-sensitive transfer image-receiving sheet curls toward the image-receiving layer side,
So-called plus curl was generated, the handleability was poor, and in some cases jamming occurred in the printer. Furthermore, it has been found that the heat-resistant layer after curing may be cracked when an external force such as bending is applied, and the quality may be significantly impaired.

In order to improve these problems, the inventors of the present invention conducted extensive studies and found that the average acryloyl equivalent of the radiation-curable resin composition forming the heat-resistant layer was 100-19.
0, and a curable property and an acryloyl equivalent by providing a heat-resistant layer containing a radiation-curable resin having flexibility of 150 to 280 in the range of 10 to 50 wt% in the heat-resistant layer on the porous film. It was found that an image-receiving sheet for heat-sensitive transfer having excellent transportability in the printer can be obtained.
Further, it has been found that such a heat-resistant layer makes it possible to obtain a heat-resistant layer having good resistance to film cracking without lowering image bleeding resistance. Here, if the average acryloyl equivalent of the radiation curable resin composition is less than 100, the heat shrinkage of the heat-resistant layer is large, so a resin coating layer on one side of the base paper and a porous film on the other side are used. However, the positive curl of the heat-sensitive transfer image-receiving sheet is not improved, and the heat-resistant layer is significantly cracked. Further, when the average acryloyl equivalent exceeds 190, image bleeding occurs because the dye diffuses from the image-receiving layer after printing into the heat-resistant layer over time. When the content of the radiation curable resin having an acryloyl equivalent of 150 to 280 is less than 10% by weight, the positive curl of the heat-sensitive transfer image-receiving sheet is not improved and the heat-resistant layer is cracked.
If the content exceeds 50% by weight, image bleeding tends to occur. Furthermore, if a radiation-curable resin having an acryloyl equivalent of more than 280 is contained, the image bleeding resistance is deteriorated regardless of the added amount.

The radiation-curable resin composition in the present invention is a mixture of at least two kinds of radiation-curable resins, and the average acryloyl equivalent is the acryloyl equivalent of each radiation-curable resin. It is the arithmetic mean value.

Hereinafter, typical radiation curable resins that meet the above matters will be exemplified, but the present invention is not limited to these. In addition, () shows the acryloyl equivalent.

A) Aronix M-101 (236),
Aronix M-120 (272), Aronix M-
132 (262), Aronix M-150 (11
1), Aronix M-152 (248), Aronix M-154 (230), Aronix M-210 (2
56), Aronix M-205 (267), Aronix M-215 (185), Aronix M-220.
(141), Aronix M-233 (255), Aronix M-240 (142), Aronix M-24
5 (261), Aronix M-305 (99), Aronix M-309 (99), Aronix M-310
(157), Aronix M-315 (141), Aronix M-320 (215), Aronix M-32.
5 (179), Aronix M-400 (96), Aronix M-5300 (277), Aronix M-5
400 (264), Aronix M-5500 (21
6), Aronix M-5700 (222), Aronix M-6100 (225), Aronix M-625
0 (225), Aronix M-6300 (239),
Aronix M-6500 (223), Aronix M
-7100 (188), Aronix M-8030 (1
19), Aronix M-8060 (136) and Aronix M-8100 (155) and above, Aronix series manufactured by Toa Synthetic Chemical Industry Co., Ltd.,

B) Kayarad TC-100S (27
0), Kayarad R-564 (249), Kayarad R
-128H (222), Kayarad HDDA (11
3), Kayarad NPGDA (106), Kayarad T
PGDA (150), Kayarad PEG400DA (2
61), Kayarad MANDA (156), Kayarad HX-220 (270), Kayarad R-551 (25)
6), Kayarad R-712 (242), Kayarad R
-604 (163), Kayarad R-167 (18
7), Kayarad R-684 (152), Kayarad P
ET-30 (149), Kayarad GPO-303 (2
32), Kayarad TMPTA (148), Kayarad THE-330 (214), Kayarad TPA-320.
(206) and Kayarad TPA-330 (235) or more, Nippon Kayaku Co., Ltd. Kayarad series,

C) NK ester APG-10G (19
2), NK ester AMP-20G (236), NK ester A-SA (216), NK ester LA (24)
0), NK ester A-200 (154), NK ester A-400 (254), NK ester A-HD (11
3), NK ester A-NPG (106), NK ester APG-200 (150), NK ester APG-4
00 (268), NK ester A-BPE-4 (25
6), NK ester TMPT (113), NK ester A-TMPT (99), NK ester A-TMM-3
(75), NK ester A-MM-3L (75), NK
Ester A-TMMT (88) or higher, Shin-Nakamura Chemical Co., Ltd.
NK ester series

In order to improve the whiteness of the heat-sensitive transfer image-receiving sheet, barium sulfate, titanium dioxide, zinc sulfide, calcium carbonate, magnesium oxide, aluminum oxide, titanium phosphate, satin may be incorporated in the heat-resistant layer of the present invention. White pigments such as white, talc, clay, and coloring pigments,
Blue pigments and dyes such as cobalt blue, ultramarine blue, cerian blue, and phthalocyanine blue can also be added. Further, if necessary, within a range that does not impair the effects of the present invention,
Various additives such as a fluorescent whitening agent, an antioxidant, an ultraviolet absorber, a stabilizer, a radical polymerization initiator, a surfactant, a lubricant, an antistatic agent and a conductive agent can be added. here,
The fluorescent whitening agent added to the heat-resistant layer is not particularly limited, but a fluorescent whitening agent containing a thiophene skeleton, which is excellent in radiation resistance and weather resistance, is particularly preferable.

As the ionizing radiation for curing the radiation curable resin composition of the present invention, generally, ultraviolet rays, α rays, β
Ray, γ ray, X ray, electron beam, etc., but α ray, β
Since the rays, γ rays, or X rays are accompanied by the problem of danger to the human body, ultraviolet rays and electron rays, which are easy to handle and widely used industrially, are effective.

In the present invention, when an electron beam is used,
The irradiation electron dose is preferably in the range of about 0.1 to 10 Mrad. Here, if it is less than 0.1 Mrad, sufficient curing effect cannot be obtained and curing is insufficient, and if it exceeds 10 Mrad, the support is deteriorated, which is not preferable. As an electron beam irradiation method, a scanning method, a curtain beam method, or the like can be used, and the electron beam acceleration voltage is preferably about 100 to 300 KV.

When ultraviolet rays are used in the present invention, a sensitizer must be added to the radiation curable resin composition. Specific examples thereof include di- or trichloroacetophenone. Acetophenones, benzophenone, Michler's ketone, benzyl, benzoin,
There are benzoin alkyl ether, benzyl dimethyl ketal, tetramethyl thiuram monosulfide, thioxanthones, azo compounds and the like, and they are selected from the viewpoint of the polymerization reaction type of the radiation curable resin, stability, compatibility with a radiation irradiation device, and the like. The amount of the sensitizer used is usually about 1 to 5% by weight based on the radiation curable resin. In addition, a storage stabilizer such as hydroquinone may be used in combination with the sensitizer. As the light source, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, a tungsten lamp or the like is used.

The method for applying the heat-resistant layer made of the radiation-curable resin composition on the porous film in the present invention includes, for example, blade method, air doctor method, squeeze method, air knife method, reverse roll method,
Methods such as a gravure roll and transfer roll system, a bar system and a curtain system are used. Further, for the purpose of obtaining a higher smooth surface, for example, Japanese Patent Application Laid-Open No. 4-1138
A method of transferring a highly smooth metal roll or the surface of a plastic film to the heat-resistant layer as described in JP-A-91, etc. can also be adopted. That is, a heat-resistant layer made of a radiation-curable resin composition is applied between a porous film and a mirror-finished metal roll or a highly smooth plastic film, and the metal roll or plastic film is peeled off after being irradiated with radiation to be cured. And a highly smooth heat-resistant layer.

Any image-receiving layer in the present invention can be suitably used as long as it has a strong interaction with a dye and the dye can be stably diffused into the resin.
No. 169370, No. 57-20750, No. 60-25793, etc., polyester resin, polyacrylic ester resin, polycarbonate resin, polyvinyl acetate resin, styrene acrylate resin, polyurethane resin, Polyamide resin, urea resin, polycaprolactone resin, polystyrene resin, polyvinyl chloride, polyacrylonitrile resin, etc. can be used. Further, copolymers such as vinyl chloride / vinyl acetate copolymers and styrene / butadiene copolymers containing at least one of the constitutional units of these resins as a main component can also be used. Further, these resins can be used alone or in combination of two or more. These resins can be dissolved in water or an organic solvent and applied on a support, or can be applied as an emulsion.

In the present invention, a releasing agent may be added to the image receiving layer in order to prevent blocking with the transfer sheet. Examples of such a releasing agent include higher fatty acids or esters thereof, amides or metal salts thereof, waxes such as shellac wax, montan wax, carnauba wax, polyethylene wax, Teflon powder, fluorine-based or phosphate-based surfactants. Modified silicone oils such as silicone oil, amino modified silicone, epoxy modified silicone, alkyd modified silicone and polyester modified silicone can be used. Further, as the silicone compound, a reaction-curable type, an ionizing radiation-curable type, a catalyst-curable type and the like can be used if necessary.

Further, if necessary, the image receiving layer is provided with additives such as dyes, pigments, wetting agents, defoaming agents, dispersants, antistatic agents, optical brighteners, ultraviolet absorbers and light stabilizers. It can be added. As the pigment, an inorganic pigment or an organic pigment represented by silica, alumina, titanium oxide, calcium carbonate, kaolin, clay, zinc oxide, barium sulfate or the like can be added.

In the present invention, the coating amount of the image receiving layer is preferably in the range of 0.5 to 30 g / m ² in terms of dry solid content. As a method for applying the image receiving layer, a general application method such as an air knife method, a gravure method, a wire bar method, a rod method, a reverse roll method, an extrusion die method, a blade method, a slide hopper method, or the like is used.

In the present invention, in order to improve the adhesion between the support and the image-receiving layer, the surface of the heat-resistant layer is subjected to corona discharge treatment,
It is also possible to modify by plasma treatment, flame treatment or the like.

In the present invention, on the polyolefin resin coating layer on the side opposite to the image receiving layer of the support, for the purpose of improving the transportability of the heat-sensitive transfer image receiving sheet during printing and imparting writability and conductivity to the back surface. A backing layer containing an inorganic pigment, an organic pigment, an antistatic agent, etc. can be provided. Such inorganic pigments added to the backing layer include silica, alumina, titanium oxide, calcium carbonate, kaolin, clay, zinc oxide and barium sulfate, and antistatic agents include quaternary ammonium salts and polyamines. Cationic surfactants such as derivatives, anionic surfactants such as alkyl phosphates,
Examples thereof include amphoteric surfactants such as sulfobetaine and nonionic surfactants such as polyethylene glycol.

[0049]

According to the present invention, an image-receiving sheet for heat-sensitive transfer is provided with an image-receiving layer for receiving a dye from a thermal transfer medium on the surface of the support, wherein the support contains a specific amount of high density polyethylene on one surface of the base paper. Covering a resin coating layer consisting of a polyolefin resin, affixing a porous film to the other surface, containing a specific amount of a radiation curable resin having a specific acryloyl equivalent on the non-adhesive surface of the film, and a specific A heat-resistant layer comprising a radiation-curable resin composition having an average acryloyl equivalent is provided, and the curl characteristic of the image-receiving sheet for heat-sensitive transfer having the image-receiving layer on the heat-resistant layer, good transportability in a printer, and It is possible to obtain an image-receiving sheet for heat-sensitive transfer which is excellent in image bleeding resistance and resistance to film cracking of the heat-resistant layer.

[0050]

EXAMPLES Next, the present invention will be described in more detail by way of examples, but the contents of the present invention are not limited to these. Further, "parts" and "%" shown in Examples and Comparative Examples are parts by weight and% by weight, respectively.

The ink donor sheet for evaluation was prepared as follows. [Transfer sheet] A biaxially stretched polyester film having a film thickness of 5 μm and coated with a heat resistant slipping layer coating solution having the following composition with a wire bar so that the dry coating amount is 0.5 g / m 2 Then, it was irradiated with ultraviolet rays with a high pressure mercury lamp of 140 W / cm ² to cure it. (Heat resistant slipping layer coating liquid) TMPTA (Daiichi Kogyo Seiyaku) 10 parts Lipoxy SP1509 (Showa High Polymer) 20 parts Trefill E500 (Toray Dow Corning Silicone) 9 parts KF-393 (Shin-Etsu Silicone) 0.3 parts Coronate L (Nippon Polyurethane) 0.3 part Darocur 1173 (Merck) 0.4 part Ethyl acetate 40 parts Isopropyl alcohol 20 parts

Further, a coloring material layer coating solution having the following composition was ground on a surface opposite to the heat resistant slipping layer for 2 days by a ball mill, and then dried with a wire bar so that the dry coating amount was 1.5 g / m 2. ,
A transfer sheet was prepared. (Color material layer coating solution blended) Kayaset Blue 906 (Nippon Kayaku) 10 parts Ethyl cellulose 10 parts Siloide 244 (Fuji Davison) 10 parts Isoprophyl alcohol 30 parts

Examples 1 to 15 Bleached hardwood sulfite pulp (LBSP) 50% by weight
After bleached softwood sulfite pulp (NBSP) 30% by weight and hardwood kraft pulp (LBKP) 20% by weight, a base paper (basis weight 120 g / m ² ) was subjected to a super calender treatment, and then subjected to corona discharge treatment on one side, Table 1 below
The resin coating layer shown in (4) was applied by the melt extrusion method so as to be 24 g / m ² .

Next, a polypropylene porous film having a density ratio shown in Table 1 with respect to the non-porous polypropylene was provided on the surface of the base paper having the resin coating layer.
Adhesive polyethylene resin (XLM3 manufactured by Mitsubishi Petrochemical Co., Ltd.)
After the polylaminate was adhered so that the coating amount of 1) would be 15 g / m ² , the radiation curable resin composition shown in Table 1 was applied on the non-adhering surface of the porous film in a dry coating amount of 7 g / m ^2. After coating with a wire bar to an m ^{2 of 2} , accelerating voltage 200K
The heat resistant layer was formed by irradiating an electron beam under the conditions of V and an irradiation dose of 5 Mrad.

Furthermore, a polyester resin emulsion (Vylonal MD-1) was formed on the heat-resistant layer with an air knife coater.
200: Toyobo) and an image receiving layer containing silica (Aloezil 200: Nippon Aloezil) as inorganic fine particles were coated and dried so that the dry solid content would be 5.0 g / m ^2, and Examples 1 to 1
15 heat-sensitive transfer image-receiving sheets were obtained.

Comparative Examples 1 to 17 Composition of resin coating layer, density ratio of porous film (density ratio of porous film to density 0.92 g / cm ³ of non-porous polypropylene film) and radiation curing for forming heat resistant layer Examples 1 to 15 except that the acryloyl equivalent and the solid part by weight of the resin composition are as shown in Tables 1 and 2.
In the same manner as described above, heat-sensitive transfer image-receiving sheets of Comparative Examples 1 to 17 were produced.

Comparative Example 18 The base paper surface of a base paper having a resin coating layer provided on one side was adhered to a porous film by applying an adhesive coating solution having the following composition so that the dry coating amount was 2 g / m ^2. A heat-sensitive transfer image-receiving sheet of Comparative Example 18 was produced in the same manner as in Example 1 except that the so-called dry laminating method was used. (Adhesive coating liquid) Takelac A-606 (Takeda) 90 parts Takenate A-12 (Takeda) 10 parts Ethyl acetate 90 parts

In Examples 1 to 4 and Comparative Examples 1 to 4,
Anatase type titanium dioxide was added to the radiation curable resin composition in an amount of 15% by weight based on the total weight of the composition to form a heat resistant layer.

[0059]

[Table 1]

[0060]

[Table 2]

(Evaluation Method) Each thermal transfer image-receiving sheet obtained as described above was evaluated by the following method. (1) Sensitivity The image receiving layer of each heat-sensitive transfer image-receiving sheet and the color material layer of the transfer sheet are superposed facing each other, and after printing a cyan step wedge chart using a sublimation type thermal transfer printer S3600-30 manufactured by Mitsubishi Electric, the maximum The transfer density of the sensitive area was measured with a Macbeth reflection densitometer.

(2) Image bleeding resistance The image-receiving layer of each heat-sensitive transfer image-receiving sheet and the color material layer of the transfer sheet are superposed facing each other and printed using a sublimation type thermal transfer printer S3600-30 manufactured by Mitsubishi Electric Corporation. When the image-receiving sheet for heat-sensitive transfer was left in an atmosphere of 60 ° C. and 80% RH for 5 days, bleeding of dots was observed and evaluated according to the following criteria. 5: Bleeding is not seen even when the printed portion of the heat-sensitive transfer image-receiving sheet is observed with a loupe. 4: When the printed portion of the thermal transfer image-receiving sheet is observed with a loupe, it can be seen that the image is slightly blurred. 3: When the printed portion of the heat-sensitive transfer image-receiving sheet is observed with a loupe, it can be seen that the image is blurred. 2: It can be seen with the naked eye that the printed portion of the heat-sensitive transfer image-receiving sheet is slightly blurred. 1: It can be seen with the naked eye that the printed portion of the heat-sensitive transfer image-receiving sheet is blurred.

(3) Film-cracking resistance The degree of cracking of the heat-resistant layer when the support for the image-receiving sheet for heat-sensitive transfer before coating the image-receiving layer was continuously bent 5 times was evaluated according to the following criteria. ◯: Good with no cracks. Δ: Some cracks have occurred. X: Large cracks have occurred.

(4) Curl Property When 10 sheets each of the image-receiving sheet for heat-sensitive transfer (A4 size) were placed on a flat table with the image-receiving layer side facing upward, the distances between the four corners of the image-receiving sheet for heat-sensitive transfer from the table were measured. Then, the average value was obtained. Also, after printing, the same measurement was carried out and evaluated according to the following criteria. ○: 0.5 cm or less △: 0.6 to 0.9 cm ×: 1.0 cm or more

(5) In-Printer Transportability When 50 sheets of each thermal transfer image receiving sheet were printed using the sublimation type thermal transfer printer S3600-30, the number of jamming or bending was measured, and evaluated according to the following criteria. did. ◯: 1 sheet or less △: 2 to 4 sheets ×: 5 sheets or more

The results of the above evaluations are summarized in Table 3.

[0067]

[Table 3]

Evaluation: In the heat-sensitive transfer image-receiving sheets of Examples 1 to 15, since the heat-sensitive transfer image-receiving sheets were produced by the present invention, curling characteristics before and after printing and transportability in the printer were excellent, and image bleeding resistance was high. It was possible to improve the film crack resistance of the heat resistant layer without lowering it.

However, in the heat-sensitive transfer image-receiving sheets of Comparative Examples 1 and 2, plus curl was not corrected because the content of the high-density polyethylene in the resin coating layer was too small,
Further, in the heat-sensitive transfer image-receiving sheets of Comparative Examples 3 and 4, minus curl occurred because the content of high-density polyethylene was too large. In the image-receiving sheets for thermal transfer of Comparative Examples 5, 6, and 7, the positive curl could not be corrected because the density of the high-density polyethylene was too low. In the image-receiving sheet for heat-sensitive transfer of Comparative Example 8, since the content of the radiation-curable resin having an acryloyl equivalent of 150 to 280 was too small, the heat-resistant layer lacked flexibility and cracked. Comparative Examples 9 and 1
In the image receiving sheet for thermal transfer of No. 0, the content of the radiation curable resin having an acryloyl equivalent of 150 to 280 was too much, and thus the image bleeding resistance was poor. In the image-receiving sheet for heat-sensitive transfer of Comparative Example 11, the density of the porous film was too high, the transfer density was poor, and the curl property and the transport property were slightly inferior. In the image-receiving sheet for heat-sensitive transfer of Comparative Example 12,
The average acryloyl equivalent of the radiation curable resin composition is 10
Since it was less than 0, the heat resistant layer was cracked and the positive curl was not corrected. Further, in the image-receiving sheet for heat-sensitive transfer of Comparative Example 13, the average acryloyl equivalent of the radiation-curable resin composition exceeded 190, so the image bleeding resistance was lowered. The heat-sensitive transfer image-receiving sheets of Comparative Examples 14 and 15 did not contain a radiation-curable resin having an acryloyl equivalent of 150 to 190, so that the heat-resistant layer was significantly cracked. Since the image-receiving sheets for thermal transfer of Comparative Examples 16 and 17 contained the radiation curable resin having an acryloyl equivalent of more than 280, the image blur resistance was deteriorated. In the heat-sensitive transfer image-receiving sheet of Comparative Example 18, since the resin-coated paper and the porous film were attached by the dry lamination method, the heat-sensitive transfer image-receiving sheet was inferior in curling property and poor in transportability.

[0070]

The image-receiving sheet for heat-sensitive transfer of the present invention has, as a support, one surface coated with a polyolefin resin containing a specific amount of high-density polyethylene, and a specific porous film adhered to the other surface of the base paper. By using a support provided with a heat-resistant layer made of a specific radiation-curable resin composition and providing an image-receiving layer on the heat-resistant layer of the support, curl characteristics of the heat-sensitive transfer image-receiving sheet and transportability in the printer are good. In addition, it is possible to obtain an image-receiving sheet for heat-sensitive transfer which is excellent in image bleeding resistance and film crack resistance of the heat-resistant layer.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a heat-sensitive transfer image-receiving sheet of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resin coating layer 2 Base paper 3 Porous film 4 Heat resistant layer 5 Image receiving layer 6 Support

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuhiko Sunada 3-4 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Paper Mills, Ltd.

Claims (2)

[Claims] 1. An image-receiving sheet for heat-sensitive transfer comprising an image-receiving layer for receiving a heat transferable dye from a thermal transfer medium on a support, wherein the support is JIS K6748 on one side of a base paper.
Provided with a resin coating layer consisting of a polyolefin resin containing 10 to 80% by weight of a high-density polyethylene resin having a density of 0.95 g / cm ³ or more as defined in 1., and 85% of the non-porous film of the same material on the other surface. A porous film having the following density is adhered, and at least one or more acryloyl equivalent of 150 to 280 radiation curable resin is added to 10 to 5
Contains 0% by weight and has an average acryloyl equivalent of 100 to 1
90. An image-receiving sheet for heat-sensitive transfer, which is the support provided with a heat-resistant layer of 90 radiation-curable resin composition, and the image-receiving layer is provided on the heat-resistant layer. 2. The coating of a resin coating layer of a polyolefin resin or the attachment of a porous film to a base paper is performed by a polylamination method using a molten polyolefin resin as an adhesive. Claim 1 characterized by the above-mentioned.
Or an image-receiving sheet for heat-sensitive transfer according to item 2.