JPH05185746A - Image receiving sheet for thermal transfer - Google Patents

Abstract

PURPOSE:To obtain an image receiving sheet for thermal transfer which dyes easily by low energy by a method wherein an image receiving layer which contains a specific quantity of specific radiation setting resin provided onto a base material is cured by high energy beams. CONSTITUTION:A coating solution is prepared by dissolving a specific quantity of radiation setting resin having an isobornyl skelton expressed by the formula I (R represents an hydrogen and a methyl group) in an appropriate solvent. An image receiving layer which contains 5-80wt.% of radiation setting resin to be expressed by the formula I is formed by applying and drying the coating solution onto a base material of coated paper, synthetic resin, etc. The image receiving layer is hardened by irradiating the image receiving layer with at least one kind of high energy beams selected in electron beams and ultraviolet light, and an image receiving sheet for thermal transfer is obtained. A compound having the isobornyl skeleton composing the image receiving layer is high in affinity to a sublimate dye and easily dyes the dye of an ink donor sheet when heat is applied.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention has an image receiving layer provided on a support such as paper, laminated paper, glass paper, synthetic paper, non-woven fabric and synthetic resin film, and is excellent in sublimation dye acceptability and blocking property. The present invention relates to a heat-sensitive transfer image-receiving sheet.

[0002]

2. Description of the Related Art In recent years, a sublimation-type thermal transfer printer has been used as a means for color hard copy, particularly for reproducing multicolor gradation. The principle of such a sublimation-type thermal transfer printer is that an image is converted into an electric signal, and the electric signal is further converted into a heat signal by a thermal head to convert a sheet (ink donor sheet) coated with a sublimable ink. The heated and sublimated ink is fixed on the heat-sensitive transfer image-receiving sheet that is in close contact with the ink donor sheet, and the image is reproduced.

A conventional image-receiving sheet for heat-sensitive transfer has an image-receiving layer containing a thermoplastic resin such as polyester, polyamide, cellulose acetate or acrylic resin as a main component on a support such as paper, synthetic paper or a film filled with white pigment. It is provided. Since these thermoplastic resins are applied using a solvent, there is a problem in the process.

A method of using a radiation curable resin instead of a part of the thermoplastic resin in the image receiving layer in the sublimation type thermal transfer method is also disclosed in JP-A-58-212994 and JP-A-6-212994.
Although proposed in 2-173295 and 63-74691, these methods still have problems in acceptability of sublimable dyes.

[0005]

DISCLOSURE OF THE INVENTION The present invention is directed to an image-receiving sheet for heat-sensitive transfer, which has an image-receiving layer which is cured by irradiation with electron beams or ultraviolet rays, can be easily dyed even at low energy, and can obtain a high-density image. Is to provide.

[0006]

According to the present invention, among the compounds having an unsaturated bond capable of being polymerized by an electron beam, the compound having the structure of the general formula 1 is excellent in sublimation dye acceptability. It was made based on. That is, in the heat-sensitive transfer image-receiving sheet of the present invention, the radiation-curable resin having the structure of the general formula 1 is used on at least one surface of the support in an amount of 5 to 8
It is obtained by providing an image receiving layer containing 0% by weight, and curing the image receiving layer with one or more high energy rays selected from electron beams and ultraviolet rays.

In the general formula 1, R is hydrogen or a methyl group. When the radiation-curable resin having the structure of the general formula 1 is contained in the image-receiving layer in an amount of 5 to 80% by weight, an image-receiving sheet excellent in sublimable dye accepting property and blocking property can be obtained. The effect of addition is small, 80%
If it exceeds, curing will be insufficient and the surface will become sticky, and unnecessary parts will be dyed, which is not preferable.

The present invention will be described in detail below.

The radiation curable resin used in the present invention is
It is a compound having an isobornyl skeleton represented by the general formula 1.

Since the curing is not sufficient when the above monomers are used alone, it is preferable to mix and use other general radiation curable resins in order to accelerate the curing.

The radiation-curable resin is a compound having at least one carbon-carbon unsaturated bond, and specifically includes acryloyl group, methacryloyl group, ethacryloyl group,
A compound containing an acrylamide group, an allyl group, a vinyl ether group, a vinyl thioether group, or the like. For example, acrylic acid alkyl ester, methacrylic acid alkyl ester, acrylonitrile, methacrylonitrile,
Examples thereof include acrylamide, vinyl acetate, vinyl propionate, vinylpyrrolidone and the like. There may be two or more unsaturated bonds in the molecule. In particular, unsaturated esters of polyols such as ethylene diacrylate, diethylene glycol diacrylate, glycerol triacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, etc. can be mentioned. Further, it may be a compound having one or two or more epoxy rings, such as glycidyl acrylate. Furthermore, these compounds may be high molecular weight compounds. A compound having an acrylate group at the terminal or side chain of the polymer chain is particularly preferable, and is a prepolymer having a polyester skeleton, a polyurethane skeleton, an epoxy resin skeleton, a polyether skeleton, or a polycarbonate skeleton.

Of the radiation curable resins, typical ones will be exemplified below.

(A) Polyester acrylate, polyester methacrylate For example, Aronix M-5300, M-5400, M-5500, M-560
0, M-5700, M-6100, M-6200, M-6300, M-6500, M-710
0, M-8030, M-8060, M-8100 (above, product name of Toagosei Chemical Industry Co., Ltd.), Viscoat 700, 3700 (above, product name of Osaka Organic Chemical Industry Co., Ltd.), Kayarad HX-220, HX-620
(These are the product names of Nippon Kayaku Co., Ltd.)

(B) Epoxy acrylate, epoxy methacrylate For example, NK ester, EA-800, EPM-800 (above, Shin Nakamura Chemical Co., Ltd. trade name), Viscoat 600, 540 (above, Osaka Organic Chemical Industry Co., Ltd.) (Product name), Photomer 3016, 3082
(Above, San Nopco Ltd. product name)

(C) Urethane acrylate, urethane methacrylate For example, Aronix M-1100, M-1200, M-1210, M-125
0, M-1260, M-1300, M-1310 (above, product name of Toagosei Chemical Industry Co., Ltd.), Viscoat 812, 823, 823 (above, product name of Osaka Organic Chemical Industry Co., Ltd.), NK ester, U-108-
A, U-4HA (trade name of Shin Nakamura Chemical Co., Ltd.)

(D) Monofunctional acrylate, monofunctional methacrylate For example, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 2-
Hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, phenoxyethyl acrylate, cyclohexyl acrylate, cyclohexyl methacrylate, benzyl acrylate, glycidyl methacrylate, N, N-dimethylaminoethyl acrylate, N, N- Dimethylaminoethyl methacrylate, N,
N-diethylaminoethyl methacrylate, butoxyethyl acrylate, etc. Ethylene oxide-modified phenoxy phosphoric acid acrylate Ethylene oxide-modified butoxylated phosphoric acid acrylate, and other products Toa Gosei Chemical Industry Co., Ltd.
Aronix M-101, M-102, M-111, M
-113, M-114, M-117, M-120, M-152, M-154 and the like.

(E) Polyfunctional acrylate, polyfunctional methacrylate, polyfunctional oligomer For example, 1,6-hexanediol diacrylate, 1,6-
Hexanediol dimethacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, pentaerythritol diacrylate, dipentaerythritol hexaacrylate, isocyanuric acid diacrylate , Pentaerythritol triacrylate, isocyanuric acid triacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethylene oxide modified pentaerythritol tetraacrylate, propylene oxide modified pentaerythritol tetraacrylate,
Examples thereof include propylene oxide-modified dipentaerythritol polyacrylate and ethylene oxide-modified dipentaerythritol polyacrylate. The product name of Toagosei Kagaku Kogyo Co., Ltd. is Aronix M-210, M-21
5, M-220, M-230, M-233, M-240, M-245, M-305, M-30
9, M-310, M-315, M-320, M-325, M-330, M-400, TO-45
8, TO-747, TO-755, THIC.TA2, Nippon Kayaku Co., Ltd.'s trade names are Kayarad TC-110S, TC-120S, HDDA, NPGD
A, TPGDA, PEG400DA, MANDA, HX-220, HX-620, R-551,
R-712, R-604, R-167, TPA-320, TPA-330, PET-30, Kayarad D-310, D-330, Kayarad DPHA, Kayarad DP
The product names of CA-20, DPCA-30, DPCA-60, DPCA-120, Shin-Nakamura Chemical Co., Ltd. are A-200, A-400, A-600, A-HD, A.
-NPG, APG-200, APG-400, A-BPE-4, A-BPE-10, 701-A,
A-BPP-3 etc. are mentioned.

(F) Others Examples include monomers such as vinylpyrrolidone and acryloylmorpholine.

Various additives such as an antioxidant, an antistatic agent, a dispersant, a stabilizer, a pigment and a lubricant may be appropriately combined and added to the radiation curable resin composition of the present invention.

In the present invention, the surface of the support may be subjected to surface treatment such as corona treatment or subcoating in order to improve the adhesion and wettability between the support and the ink receiving layer.

A resin coating layer is formed on the back surface of the image-receiving sheet for heat-sensitive transfer of the present invention by applying a polyolefin resin by a melt extrusion method or by applying a radiation-curable resin and then forming a coating by irradiation with radiation. A back coat layer can be provided to prevent curling, to prevent static, and to provide writability. The backcoat layer may contain an antistatic agent, a hydrophilic binder, a latex, a film hardener, a pigment, a surfactant and the like in an appropriate combination.

The support used in the present invention includes ordinary natural pulp paper, and coated paper, laminated paper, glass paper, synthetic fiber, synthetic resin film or so-called synthetic paper obtained by simulating synthetic resin film,
Nonwoven fabric or the like can be used. Not specifically defined, the thickness of the support preferably has a smooth, its basis weight 30g / m ² ~300g / m ² is preferred.

A precoat layer may be provided between the support of the present invention and the image-receiving layer for the purpose of averaging unevenness of the support and improving whiteness and opacity. Inorganic coating layers such as clay, talc, kaolin, and ansilex, polyethylene (high-density polyethylene, low-density polyethylene, medium-density polyethylene, linear low-density polyethylene), polypropylene, polybutene, etc. Organic materials such as homopolymers of thermoplastic resins such as polypentene and polyethylene terephthalate, or copolymers of two or more olefins such as ethylene / propylene copolymers can be used, and these resins can be used alone or as a mixture. Can be used. White pigments for improving whiteness and opacity may be contained in these resins. Hollow particles may be contained for the purpose of improving the adhesion to the ink donor sheet and the heat insulation of the image receiving layer.

As a method for preparing the radiation curable resin, a general pigment kneader can be used. For example, a two-roll, a three-roll, a ball mill, a kneader, a high speed mixer, a homogenizer and the like.

The radiation-curable resin may be coated on the support by, for example, blade coating, doctor coating, air knife coating, spray coating, squeeze coating, reverse roll coating, gravure roll and transfer roll coating, extrusion coating. , Curtain coating, die coating, etc. are used,
The radiation-curable resin may be applied to the support and then smoothed with a calendar or the like.

The thickness of the image-receiving layer made of a radiation-curable resin varies depending on the type and smoothness of the base paper, but is 2 to 100 μm.
m, more preferably 3 to 50 μm, and if it is thinner than this thickness, sufficient properties cannot be obtained from the viewpoints of acceptability of sublimable dye, whiteness and opacity, and it is difficult to apply uniformly. It is difficult to form a coating layer that is smooth and uniform, which is not preferable in terms of quality.

When the surface of the heat-sensitive transfer image-receiving sheet is to be further mirror-finished or model-finished, the surface to be treated is brought into contact with a mirror-roll or model-roll, and the back surface of the sheet is irradiated with radiation to be cured to give a mirror-finish. be able to. After applying the radiation-curable resin, the material is brought into contact with a material having a smooth surface such as a plastic sheet and irradiated with radiation from the surface of the plastic sheet or the surface of the support to cure the radiation-curable resin to form a smooth surface. Can be transcribed. In addition, there is also a method in which preliminary irradiation is performed in advance to partially cure the surface, and then secondary irradiation is performed by bringing the surface into contact with a mirror roll or a shaping roll to completely cure it.

When electron beam irradiation is used, the accelerating voltage is 100 to 1000 KV, more preferably 100 to 300 KV in terms of penetrating power and hardening power, and more preferably 100 to 300 KV, and the absorbed dose per one pass is 0.5 to. It is preferably set to 20 Mrad. If the accelerating voltage or the electron beam irradiation amount is lower than this range, the electron beam penetrating power is too low to sufficiently cure the inside of the support, and if it is higher than this range, not only the energy efficiency deteriorates. However, there is an unfavorable influence on the quality such as a decrease in the strength of the support and a decomposition of the resin and additives. As the electron beam accelerator, for example,
Electro curtain system, scanning type,
Any type such as double scanning type may be used.

When the electron beam is irradiated with a high oxygen concentration, the curing of the electron beam curable resin is hindered. Therefore, replacement with an inert gas such as nitrogen, helium or carbon dioxide is performed.
Irradiation is preferably performed in an atmosphere in which the oxygen concentration is suppressed to 600 ppm or less, preferably 400 ppm or less.

In the case of ultraviolet irradiation, it is preferable to use a lamp of 80 W / cm or more. For example, a low pressure mercury lamp,
There are medium-pressure mercury lamps, high-pressure mercury lamps, metal halide lamps, etc., and there is also an ozoneless type that generates less ozone. Further, a photoreaction initiator can be mixed and used in the resin. As the photoinitiator, acetophenones such as di- and trichloroacetophenone, benzophenone,
Examples include Michler's ketone, benzyl, benzoin, benzoin alkyl ether, benzyl dimethyl ketal, tetramethyl thiuram monosulfide, thioxanthones, and azo compounds.

[0031]

As a result of using the resin layer containing the radiation curable resin having the structure of the general formula 1 as the image receiving layer, an image receiving sheet excellent in sublimation dye accepting property and blocking property could be obtained.
The reason for this is not clear, but it is considered that it is due to the following reasons.

That is, the compound having an isobornyl skeleton used in the present invention has a high affinity with a sublimable dye,
As a result of easily dyeing the dye of the ink donor sheet when heat is applied, a high transfer density was obtained, and when used as a mixture with other radiation curable resin, excellent blocking property was obtained. Presumed.

[0033]

The present invention will be described in detail below with reference to examples, but the contents of the present invention are not limited to the examples. Parts in the examples are by weight unless otherwise specified.

Example 1 10 parts of isobornyl acrylate (IBA, Daiichi Kogyo Seiyaku Co., Ltd.), which is an acrylic monomer having the structure of the general formula 1, and tripropylene glycol diacrylate (M220 Toa Co., Ltd.) were coated on a corona-treated coated paper. 90)
Parts, 2 parts of benzylmethyl ketal (manufactured by IRGACURE 651, Ciba Geigy) as a photopolymerization initiator are applied by a gravure offset coater so that the coating amount becomes 8.0 g / m ² , and UV irradiation (80 W / cm, irradiation distance) 10
cm) to obtain an image-receiving sheet for heat-sensitive transfer.

Example 2 75 parts of isobornyl methacrylate (IB-X, Kyoeisha Oil and Fat Chemistry), which is a methacrylic monomer having the structure of the general formula 1, and ethylene oxide-modified bisphenol A diacrylate (on a corona-treated laminated paper) Twenty-five parts of M210 Toa Gosei Co., Ltd. was applied with a gravure offset coater so that the application amount was 8.0 g / m ² , and electron beam irradiation (175 KV, irradiation dose 10 Mrad).
To obtain an image-receiving sheet for heat-sensitive transfer.

Example 3 60 parts of isobornyl acrylate (IB-XA, Kyoeisha Oil and Fat Chemistry) which is an acrylic monomer having the structure of the general formula 1 and trimethylolpropane triacrylate (on a corona-treated cast-coated paper) M309
Toa Gosei) 40 parts by gravure offset coater
It was applied so that the application amount was 8.0 g / m ^2, and cured by electron beam irradiation (175 KV, irradiation dose 3 Mrad),
An image receiving sheet for thermal transfer was obtained.

Example 4 An image-receiving sheet for heat-sensitive transfer was obtained in the same manner as in Example 3 except that polypropylene synthetic paper was used as the support.

Example 5 The resin used in Example 2 was coated on a polyethylene terephthalate film with a gravure offset coater so that the coating amount was 7.0 g / m ² , and the film was laminated on art paper. It was cured by electron beam irradiation (175 KV, irradiation dose 10 Mrad) from the side to obtain an image-receiving sheet for thermal transfer.

Comparative Example 1 An image-receiving sheet for thermal transfer was prepared in the same manner as in Example 1 except that the amounts of isobornyl acrylate and tripropylene glycol diacrylate added in Example 1 were changed to 3 parts and 97 parts, respectively. Obtained.

Comparative Example 2 An image-receiving sheet for thermal transfer was prepared in the same manner as in Example 1 except that the amounts of isobornyl acrylate and tripropylene glycol diacrylate added in Example 1 were changed to 85 parts and 15 parts, respectively. Obtained.

Comparative Example 3 Example 3 except that the resin represented by the general formula 1 was replaced with 2-ethylhexyl carbitol acrylate (M120, Toagosei) which is a monoacrylate having no structure of the general formula 1. An image receiving sheet for thermal transfer was obtained in the same manner as in 3.

An ink donor sheet is superposed on the image-receiving sheet for thermal transfer thus obtained, and the ink donor sheet surface side 1
It was heated at 80 ° C. for 2 seconds, and the obtained transfer density and blocking property were evaluated. Regarding the transfer density, the value obtained by measuring the transfer density of cyan with a Macbeth densitometer is shown. Regarding blocking, ○ is a state where no blocking is visually observed, and × is a state where even a little blocking is seen.
The results are shown in Table 1.

[0043]

[Table 1]

Evaluation: Examples 1 to 5 using the compound represented by the general formula 1 gave good results in terms of transfer density and blocking property. On the other hand, in Comparative Example 1, the transfer density was low, and in Comparative Example 2, blocking occurred. Therefore, it is judged that the addition amounts were both inappropriate. Comparative Example 3 using 2-ethylhexyl carbitol acrylate had a low transfer density.

[0045]

As is clear from the results of Table 1, by providing the image receiving layer containing the compound represented by the structure of the general formula 1 on the support, it is possible to obtain a sublimable dye having excellent receptivity and blocking property. An image receiving sheet for thermal transfer could be obtained.

Claims (1)

[Claims] 1. An image receiving layer containing 5 to 80% by weight of a radiation curable resin having the structure of the following chemical formula 1 (general formula 1) is provided on at least one surface of a support, and the image receiving layer is selected from electron beams and ultraviolet rays. An image-receiving sheet for thermal transfer, characterized by being cured by one or more selected high energy rays. [Chemical 1] In Chemical formula 1, R represents hydrogen or a methyl group.