JPH02239985A - Dye thermal transfer image receiving sheet - Google Patents

Abstract

PURPOSE:To enhance the storage stability of a transfer image by constituting a resin coating layer of the active energy ray cured substance of a resin forming composition containing an unsaturated org. compound cured by active energy rays and a silicone compound. CONSTITUTION:A silicone compound curable by active energy rays has a structure represented by formula (I) (wherein n is a hydrogen atom or a methyl group and n is an integer of 1 or more) and, by compounding the silicone compound having an acryloyl group or a methacryloyl group at least at one terminal of the molecule thereof with a resin coating layer in an amount of 2-15% by wt. of said coating layer, an image receiving sheet forming an image enhanced in sensitivity and preservability is obtained. As an unsaturated org. compound cured by active energy rays, for example, acrylate of aliphatic, alicyclic or aromatic monohydric-hexahydric alcohol and polyalkylene glycol, polyacryloylalkyl phosphoric ester and a reaction product of carboxylic acid different from acrylic acid, polyol and acrylic acid can be designated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a dye thermal transfer image receiving sheet 1. More specifically, the present invention provides a dye thermal transfer image in which a sublimable dye image is transferred and dyed by heat, and an image with excellent density can be received with high sensitivity, and the image has excellent storage stability. This relates to a receiving sheet.

[Conventional technology]

Among high-quality color hard copies that use a thermal transfer recording method, dye transfer printers have recently been actively researched. In the dye transfer recording method, a three-color (Y, M, C) ink sheet having a sublimable dye layer is transferred by continuously controlling the heat amount and heating time of a thermal head. The amount can be continuously controlled, thereby making it possible to form full-color, tone-graded images.

Currently, receptor sheets for dye thermal transfer printers (hereinafter referred to as receptor sheets) have a resin coating layer (mainly made of polymers such as saturated copolyester polyester that has high affinity with sublimable dyes).
An image-receiving layer) is used. The coloring mechanism of the dye transfer method is “coloring material,” 59 (10), 1
986, p. 607, when a polyester resin coating layer having a relatively low glass transition temperature is locally heated, intense molecular movement occurs in the polymer chains in the amorphous region of that area, causing it to melt and soften. It becomes a viscous liquid.Next, the dye sublimated by the transfer operation jumps in, and when cooled, the dye molecules become embedded in the amorphous region, dyeing the polyester resin coating layer and forming a colored image. This dye transfer recording method requires a large amount of energy to sublimate the dye and has the drawbacks of slow transfer speed.Therefore, in order to improve the transfer speed of this method, the resin used in the resin coating layer of the receiving sheet was Attempts have been made to lower the glass transition temperature of materials.However,
In this case, the surface of the resin coating layer becomes rough due to heating during printing, resulting in a problem in that the gloss of the transferred image decreases. In even more serious cases, the resin coating layer on the receptor sheet melts completely during printing, causing the receptor sheet to adhere to the ink sheet and causing blocking when the two are peeled off. occurs.

In order to solve the above problems, Japanese Patent Application Laid-Open No. 173295/1986
Radically polymerizable oligomers that are cured by radiation,
It has been proposed to apply a coating liquid for a resin coating layer containing a monomer and/or a monomer to a sheet I-shaped substrate, and to cure this with an electron beam. This method is effective in obtaining a resin coating layer with high crosslinking density, thereby eliminating the problem of adhesion between the receiving sheet and the ink sheet. but,
During pudding 1, due to the high crosslinking density of the resin coating layer, the resin coating layer could not be melted and softened into a viscous liquid, and therefore the dye image receptivity of the resin coating layer was reduced. A new problem has arisen in that it is difficult to obtain high-density images.

Furthermore, JP-A-62-46689 proposes blending a silicone surfactant into a resin composition that can be cured by active energy rays. In this method, some of the dye dissolves into the silicone surfactant molecules during printing, which can improve the color density of the image, but over time, the dye dissolved in the surfactant However, since it diffuses into the resin coating layer together with the surfactant, problems such as expansion of the image, thickening of the character image, and reduction in the sharpness of the image occur.

[Problem to be solved by the invention]

The present invention overcomes the above-mentioned drawbacks of the prior art, namely:
An object of the present invention is to provide a dye thermal transfer image-receiving sheet that eliminates the decrease in dye image receptivity when the resin coating layer is highly crosslinked and the decrease in heat resistance when the resin coating layer is low crosslinked, and further improves the storage stability of the transferred image. It is something to do.

[Means to solve the problem]

The dye thermal transfer image receiving sheets 1 to 1 of the present invention include a sheet 1-shaped substrate and a resin coating layer formed on at least one surface of the sheet-shaped substrate, and the resin coating layer is coated with active energy rays. and a silicone compound having an acryloyl group or a methacryloyl group and cured by active energy rays, the amount of the silicone compound being: It is characterized in that the amount is in the range of 2 to 15% by weight based on the weight of the resin-forming composition.

The present inventors investigated the dyeability and heat resistance of silicone compounds that can be cured by various active energy rays, and found that the following formula is present in the molecule: , nba1
2 to 15% by weight of a silicone compound having a structure represented by (representing an integer above) and having an acryloyl group or a methacryloyl group at at least one end of the molecule based on the overall view of the resin coating layer. The inventors have discovered that an image-receiving sheet with improved sensitivity and storage stability of images formed thereon can be obtained, and the present invention has been completed.

Examples of silicone compounds curable with active energy rays in the present invention include the following.

(1) A reaction product of dimethylborisiloxane, γ-methacrylicpropyltrimethoxysilane, and hexyl alcohol. Its specific structure is shown in formula (1).

CI13 (In formula (1), * represents -C=CI12, and n represents an integer of 1 or more) (2) Dimethylpolysiloxane, 2,4 toluene diisocyanate, and 2-hydroxyethyl methacrylate-1
-Or a reaction product of 2-hydroxyethyl acrylate. Its specific structure is shown in formula (2).

(*4 represents P CHZCH200CC=CHZ, n represents an integer of 1 or more, R represents a methyl group or a hydrogen atom) The content of the silicone compound used in the present invention in the resin coating layer is: Preferably 2 to 15 based on the total resin coating layer weight
If it is less than 2% by weight, blocking between the ink sheet and the image-receiving sheet during printing 1 may be insufficiently prevented;
When the amount exceeds 5% by weight, a large amount of energy is required to cure the resin coating layer, and the storage stability and sharpness of images may deteriorate.

The reasons why the resin coating layer for a receiving sheet exhibits excellent performance by blending the above silicone compound into the resin coating layer include the following.

(1) Since the siloxane polymer has a fairly low glass transition temperature, the dye sublimated from the ink sheet easily jumps into the resin coating layer.

(In the above formula (2), *1 represents P CI12C}1200CC=CH2, n represents an integer of 1 or more, and R represents a methyl group or a hydrogen atom) (
3) Reaction products of dimethylborisiloxane, 4.4 methylene diphenyl diisocyanate, and 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate. Its specific structure is shown in formula (3).

(In the above formula (3), *3 is ■ C113 (2) The double bond group in the acryloyl group and/or methacryloyl group is ring-opened by irradiation with active energy rays and causes a curing reaction, but silicone Due to the low surface energy of the polymer compared to other polymers, adhesion between the ink sheet and the receiving sheet 1 does not occur even at low crosslinking densities.

(3) Since the above-mentioned double bond group is ring-opened and crosslinked by active energy ray irradiation, diffusion of the dyed silicone resin is suppressed.

Examples of the unsaturated organic compounds that can be cured by active energy rays used in the present invention include the following compound groups.

(1) Acrylates of aliphatic, alicyclic, and araliphatic mono- to hexavalent alcohols and polyalkylene glycols.

(2) Acrylate of a hydroxyl compound obtained by adding an alkylene oxide to an aliphatic, alicyclic, or araliphatic mono- to hexavalent alcohol.

(3) Polyacrylic alkyl phosphate ester.

(4) Carboxylic acid and polyol different from acrylic acid,
Reaction product with acrylic acid.

(5) Reaction product of isocyanate, polyol, and acrylic acid.

(6) A reaction product between an epoxy compound and acrylic acid.

(7) A reaction product of an epoxy compound, a polyol, and an acrylic acid.

etc. can be mentioned. Specific examples of such active energy-based curable unsaturated organic compounds include polyoxyethylene epichlorohydrin-modified bisphenol A diacrylate, dicyclohexyl acrylate-1, shrimp chlorohydrin-modified polyethylene glycol diacrylate, and 1,6-hexane. Diol diacrylate, human xybihalic acid ester neobentyl glycol diacrylate, nonyl phenoxy polyethylene glycol acrylate, ethylene oxide modified phenoxylated phosphoric acid acrylate, ethylene oxide modified phthalic acid acrylate, polybutadiene acrylate-1, cabrolactane modified tetrahydride Furfuryl acrylate, tris(acryloxyethyl) inocyanurate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate-1, polyethylene glycol diacrylate, 1,4-butadiene diol diacrylate, neopentyl glycol diacrylate, neopentyl glycol-modified trimethylolpropane diacrylate, and the like.

The resin-forming composition of the present invention is cured by irradiation with active energy rays such as electron beams and ultraviolet rays.

When using an electron beam as the active energy beam, it is preferable to use a curtain beam type electron beam accelerator that is relatively inexpensive and can provide high-output electron beam irradiation. In this curtain beam method, the acceleration voltage is generally 100 to 30
0 Kv, and the absorbed dose is 045-1Q Mrad. In addition, the oxygen concentration in the atmosphere during electron beam irradiation was 500
It is preferably less than ppm. This is 500ppm
If it is larger, oxygen may act as a retarder for the polymerization of the compound, resulting in insufficient curing.

When ultraviolet rays are used as active energy rays, a photoreaction initiator is added in an amount of 0.1 to 10% by weight based on the total amount of the resin forming composition. Specific examples of the photoreaction initiator include a mixture of a benzophenone compound and an amine compound, a mixture of a thioxanthone compound and an amine compound, an acetophenone compound, a ketal compound, and a benzoin ether compound.

Examples of the sheet-like substrate used in the present invention include various plastic films such as high-quality paper, coated paper, synthetic paper of biaxially stretched film containing polyolefin and inorganic pigment as main components, and laminated sheets made of a combination thereof. It can be used. It is preferable that the sheet-like substrate used in the present invention has a thickness of 20 to 250 g/n and a basis weight of 20 to 250 g/n.

Examples of methods for applying the resin forming composition for forming a coating layer to the sheet-like substrate include methods using bar coating, air doctor coating, blade coating, squeeze coating, air knife coating, reverse roll coating, transfer coating, etc. There is. The thickness of the coating layer obtained at this time is preferably 2 to 20 mm after electron beam curing. If the thickness of the coating layer is thinner than 2 tm, the density and sensitivity of the resulting image will decrease, and the thickness will vary, resulting in a decrease in the uniformity of the image. Moreover, if the thickness becomes thicker than 20 gn, the density and sensitivity of the image become saturated, which is rather uneconomical.

〔Example〕

The present invention will be explained in detail with reference to Examples. However, the present invention is not limited thereto.

disaster ship flame earth Composition below: A resin-forming composition was prepared having:

Me Me The above composition was applied as a coating liquid to a synthetic paper (manufactured by Oji Yuka Synthetic Paper Co., Ltd.) with a thickness of 150 JIm using a Hercoater so that the coating amount was 10 g/m.

Next, this coating layer was irradiated with an electron beam at an absorbed dose of 4 Mrad to cure the coating layer, thereby forming a resin coating layer to prepare an image-receiving sheet. A resin-forming composition was prepared in which this resin coating layer had dyeability with respect to sublimable dyes. This composition was used as a coating liquid to a thickness of 150 μm.
It was applied onto synthetic paper (manufactured by Oji Yuka Synthetic Paper) using a Hercoater at a coating amount of 10 g/r4. Example 1 below
An electron beam cured resin coating layer was formed by the same operation as above. The image receiving sheet thus obtained was subjected to the same printing operation as in Example 1. Table 1 shows the density of the 10th gradation of the obtained stamp pattern image and the sensory evaluation results of the image after the printed receiving sheet was left at 65° C. for 2 weeks.

The composition below is as follows: Next, a step pattern image produced by a color bar signal generator (trademark: C13A2, manufactured by Shibazoku Co., Ltd.) was printed on this image-receiving sheet using a dye thermal transfer printer (trademark: vy-2o, manufactured by Hitachi, Ltd.). (Black print made by overlapping three colors of ink: yellow, magenta, and cyan). The density of the step pattern image received on the image receiving sheet and the printed receiving sheet were heated at 65°C2.
Table 1 shows the sensory evaluation results of the images after being left for a week.

The density of the printed image is measured using the Macbeth densitometer (trademark:
RD-914, Kollmorgen Corp. (manufactured by).

A resin forming composition having the following composition was prepared. This composition was used as a coating liquid and was applied onto synthetic paper (manufactured by Oji Yuka Synthetic Paper) with a thickness of 150 lm using a har coater so that the coating amount was 10 g/rd. Thereafter, the same operations as in Example 1 were carried out to prepare a receiving sticker 1, which was then printed. During the printing operation, the image sheet was thermally fused to the ink sheet, making printing impossible.

A resin-forming composition having the following composition was prepared. Using this composition as a coating liquid, apply an amount of 10 g/n to synthetic paper (manufactured by Oji Yuka Synthetic Paper) with a thickness of 150 using a percoater. It was applied so that Thereafter, an image receiving sheet was prepared by performing the same operations as in Example 1, and printing was performed on this sheet. Table 1 shows the density of the obtained step pattern image in 10 gradations and the sensory evaluation results of the image after the printed receiving sheet was left at 65° C. for 2 weeks.

Table 1 [Effects of the Invention] The dye thermal transfer image-receiving sheet of the present invention has a resin coating layer for receiving and fixing a dye image, an unsaturated organic compound that is cured by active energy rays, and an acryloyl group or a methacryloyl group, The composition is formed by irradiation with active energy rays of a composition containing a silicon compound that is cured by active energy rays, and the amount of the silicon compound is limited to 2 to 15% by weight based on the total amount of the resin coating layer, and the sensitivity, It is also possible to form images with excellent storage stability.

Note 1: Density of 10th gradation of step pattern image Note 2: Image after being left at 65°C for 2 weeks Note 3: Heat fusion with ink sheet during printing ○: Good ×: Bad (Image becomes unclear)

Claims (1)

[Scope of Claims] A sheet-like substrate; and a resin coating layer formed on at least one surface of the sheet-like substrate, the resin coating layer comprising an unsaturated organic compound that is cured by active energy rays. , a cured product of a resin-forming composition containing a silicone compound having an acryloyl group or a methacryloyl group and curable by active energy rays,
A dye thermal transfer image-receiving sheet, wherein the amount of said silicone compound is within the range of 2 to 15% by weight relative to the weight of said resin-forming composition.