JPH0719051B2 - Photosensitive transfer sheet - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a photosensitive transfer sheet used for a color press proofing prepress proof and a display.

[Technical Background of the Invention and Prior Art] Conventionally, there are an overlay method and a surprint method as a color proofing method (prepress proof) using a photopolymer. The overlay method prepares multiple color proofing sheets with separated images of each color on a transparent support, and stacks these sheets (the obtained one is called a color test sheet) for color proofing. Is the way to do it. According to this method, it is possible to obtain a multicolor image by stacking two or four color proofing sheets each time, and thus it is simple and can be used for continuous inspection. The surprint method is a method in which a separated image of each color is sequentially formed on a single support to obtain a multicolor image. According to this method, the color density is not affected by the support as in the overlay method, and the color distortion that occurs when the color proofing sheets are overlaid can be avoided, and thus, it is more similar to the original printing method. It is a thing.

As an image forming material that can be used in both the overlay method and the surprint method, a release layer made of an organic polymer and a photosensitive resin layer are sequentially provided on a support (hereinafter also referred to as a temporary support). Photosensitive transfer sheets are known. For a color proofing sheet having a multicolor image for color proof, after repeating the operation of exposing and developing this photosensitive transfer sheet to form a decomposed image and then transferring the decomposed image onto an arbitrary support. Is obtained by For example, as described in JP-B-49-441, a photosensitive transfer sheet is exposed and developed through a color separation film to form a decomposed image on a release layer, and then the transfer sheet is adhered to another support. A transfer image can be formed on the support together with the release layer by pressing through the agent and then peeling off the temporary support. In this case, the adhesive has to be applied to the transfer sheet or the support at each transfer, which complicates the color proofing process,
In addition, there is a drawback that the accuracy of alignment during transfer tends to decrease.

In order to simplify the color proofing process, for example, JP-A-47-41830 discloses a photosensitive transfer sheet capable of transferring a decomposed image under heat and pressure without applying an adhesive. The release layer of the transfer sheet having such characteristics has good releasability from the temporary support at the time of thermal transfer, and is a support on the image receiving side, a non-image area (release layer) of each color and an image. Good adhesiveness to the line part is required. However, when an alcohol-soluble polyamide such as copolymerized nylon or N-alkoxymethyl nylon described in the above publication is used alone as a material for the release layer, the release layer easily absorbs water, so that the release layer is exposed to high humidity. Then, there is a tendency that the adhesion to the temporary support increases and transfer becomes impossible. Further, in the release layer made of the alcohol-soluble polyamide resin, stains such as dyes and pigments are likely to remain during development, and so-called color material fog tends to occur.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a photosensitive transfer sheet having improved transfer characteristics.

It is also an object of the present invention to provide a photosensitive transfer sheet in which the transfer characteristics are improved and the fog of the coloring material is prevented.

The above-mentioned object is a support, a photosensitive transfer sheet having a release layer made of an organic polymer and a photosensitive resin layer in this order, wherein the release layer is 4: 6 to an alcohol-soluble polyamide and a hydroxystyrene-based polymer. It can be achieved by the photosensitive transfer sheet of the present invention, which is characterized by comprising a mixture having a weight mixing ratio in the range of 9: 1.

According to the present invention, a release layer made of a mixture of an alcohol-soluble polyamide and a hydroxystyrene polymer is provided between a support and a photosensitive resin layer to improve transfer characteristics of a photosensitive transfer sheet and fogging of a coloring material. It is possible to improve various characteristics such as prevention of

That is, by using the above mixture as the release layer material, a release layer having excellent moisture resistance can be formed on the support. As a result, the peeling layer does not substantially absorb moisture even when the atmosphere in the step of transferring the decomposed image is high humidity, so that the photosensitive transfer sheet on which the image is formed is heated on a support such as an image receiving sheet. After pressure bonding, the support (temporary support) of the transfer sheet can be easily peeled from the release layer. In other words, the transfer operation can be performed without being affected by conditions such as humidity.

Further, according to the present invention, in the developing process for forming a decomposed image on the photosensitive transfer sheet, stains due to coloring materials such as dyes and pigments hardly occur on the release layer, and fog of coloring materials is not generated. It can be prevented significantly.

Furthermore, the release layer in the present invention has good adhesiveness to the image-receiving-side support, the release layer of each color and the image area, and has no adhesiveness at room temperature and adhesiveness at a temperature in the range of 50 to 150 ° C. Therefore, it is possible to perform alignment with high accuracy. Further, the release layer is insoluble in a general solvent used for forming the photosensitive resin layer and the like provided thereon, and the release layer itself is hardly colored.

[Structure of the Invention] The photosensitive transfer sheet of the present invention has a structure in which a support, a release layer, and a photosensitive resin layer are substantially provided in this order. The photosensitive transfer sheet can be produced, for example, by the method described below.

As the material of the support, a substance that is chemically and thermally stable and has flexibility is used. It may be actinic radiation transparent, if necessary. Specifically, for example, cellulose acetate, polyvinyl chloride, polystyrene, polypropylene, etc. are disclosed in JP-A-47-41830, JP-A-47-41830.
Various substances described in JP-A-48-9337 and JP-A-51-5101 can be used, but polyethylene terephthalate, polycarbonate and heat-treated products thereof are particularly preferable.

On the surface of the support opposite to the side where the release layer is provided,
A back layer made of a polymer such as polyvinyl butyral, vinyl chloride / vinyl acetate copolymer, or cellulose acetate may be provided for the purpose of improving processability. Further, the back layer may contain various additives such as a matting agent.

A release layer made of an organic polymer is provided on the support. The release layer, which is a characteristic requirement of the present invention, comprises an alcohol-soluble polyamide and a hydroxystyrene-based polymer.
It is a layer composed of a mixture with a weight mixing ratio in the range of 4: 6 to 9: 1.

As the alcohol-soluble polyamide, for example, a linear polyamide synthesized from a dibasic fatty acid and a diamine, ω-amino acid, lactam or a derivative thereof by a known method can be used. The linear polyamide may be a homopolymer, a copolymer or a block polymer. Further, a polyamide having a substituent on a carbon atom or a nitrogen atom constituting the main chain, and a polyamide having a main chain containing a bond other than a C—C bond or a C—N—C bond can also be used.

Typical examples of such polyamides include nylons 3, 4, 5, 6, 8, 11, 12, 13, 66, 610, 1313, polymers of metaxylylenediamine and adipic acid, and trimethylhexamethylenediamine. And terephthalic acid polymer, 1,
Linear homopolyamides such as polymers of 4-diaminomethylcyclohexane and suberic acid; nylon 66, 6/66/610, 6 /
66/610/612, 6/66/12, copolyamides such as ε-caprolactam / adipic acid / hexamethylenediamine / 4,4'-diaminodicyclohexylmethane; and N-methylol substitution of these various polyamides, N-alkoxy Examples thereof include alkyl-substituted and N-allyloxyalkyl-substituted derivatives.

However, the alcohol-soluble polyamide used in the present invention preferably has a viscosity (viscosity of a 10 wt% methanol solution at a temperature of 20 ° C.) of 0.2 to 70 cps.
The above alcohol-soluble polyamides may be used alone or in combination of two or more.

Examples of the hydroxystyrene-based polymer include polyhydroxystyrene and its derivatives (substitutes such as alkyl groups, alkoxy groups, and aralkyl groups),
Copolymers of hydroxystyrene with other vinyl compounds can be used. Examples of such vinyl compounds are vinyltoluene, halogenated styrene, vinylethylbenzene, methoxystyrene; N-vinylcarbazole, vinylpyridine, vinyloxazole, vinylheterocyclic compounds such as vinylpyrrolidone; vinylcycloalkanes such as vinylcyclohexane; Examples thereof include (meth) acrylic acid esters such as alkyl (meth) acrylate, aralkyl (meth) acrylate, and aryl (meth) acrylate; and acrylamides such as acrylonitrile. However, the repeating unit of hydroxystyrene in the copolymer is 40
% Or more is preferable.

The hydroxystyrene polymer used in the release layer of the present invention preferably has a molecular weight (weight average) in the range of 800 to 10,000, particularly preferably 1,200 to 8,000. Generally, an increase in the molecular weight raises the transfer temperature (temperature of thermocompression bonding), and conversely, if the molecular weight is too small, the compound tends to move to the photosensitive resin layer and exert an adverse effect. In addition, when impurities are mixed in the hydroxystyrene-based polymer, it is easily colored, and when the obtained photosensitive transfer sheet is transferred to a support such as paper, the whiteness is lowered. It is desirable to remove impurities in advance.

The ratio of the alcohol-soluble polyamide and the hydroxystyrene-based polymer is 4: 6 to 9 from the viewpoint of the releasability of the release layer from the support under high humidity and the adhesiveness to the support and the like on the image receiving side during transfer. The range is 1 (mixing ratio by weight).

The release layer can be formed by dissolving the alcohol-soluble polyamide and the hydroxystyrene polymer in a suitable solvent to prepare a coating solution, and then coating the coating solution on a support and drying. Various kinds of surfactants can be added to the coating liquid as a surface condition improver, and a fluorine-containing surfactant is particularly effective. The thickness of the release layer is generally in the range of 0.1 to 2.0 μm, preferably 0.3.
Is in the range of up to 1.0 μm.

Next, a photosensitive resin layer is provided on the release layer.

As the material for the photosensitive resin layer, various materials used for known photosensitive transfer sheets can be used, but an alkali developing type photosensitive resin is preferable. For example N
→ In case of P type, 2,6-di (4'-azidobenzal)
A blend composition of an azide-based photosensitizer such as cyclohexane and a phenol novolac resin, and a polyfunctional monomer such as trimethylolpropane triacrylate and a photopolymerization initiator such as Michler's ketone using benzyl methacrylate / methacrylic acid copolymer as a binder. The blend composition of is preferred. In the case of P → P type, a quinonediazide-based photosensitizer such as o-quinonediazide is preferable. The layer thickness of the photosensitive resin layer is generally in the range of 0.5 to 10 μm, preferably 1.0 to 5 μm.

For details of the materials for these photosensitive resin layers and the method for forming them, see, for example, Japanese Examined Patent Publication Nos. 46-15326 and 46-35682.
JP-A-47-41830, JP-A-48-93337, JP-A-49-4
No. 41, JP-A-51-5101 and JP-A-59-97140.

When a coloring substance is used, the coloring substance may be contained in the photosensitive resin layer, or may be contained in a coloring material layer provided separately. The color material layer can be provided on either the upper part or the lower part of the photosensitive resin layer, but from the viewpoint of the sensitivity (photopolymerizability) of the photosensitive resin layer in the image exposure process, the photosensitive resin is formed on the color material layer. It is preferred to provide layers. Known pigments and dyes can be used as the coloring substance, but it is preferable to use pigments (yellow, magenta, cyan, black) having a hue similar to that of the color ink for color calibration for printing. Details of the coloring material and the coloring material layer are disclosed in, for example, Japanese Patent Laid-Open No. 59-97140.

Further, in the case of N → P type, it is preferable to provide a protective layer on the negative type photosensitive resin layer. The protective layer can be formed, for example, by applying a solution of a polymer substance such as polyvinyl alcohol, polyvinyl acetate, a copolymer of methyl vinyl ether / maleic anhydride, polyvinyl pyrrolidone, gelatin, gum arabic, and drying.

The thus-produced photosensitive transfer sheet of the present invention can be used for color proofing, for example, by an operation according to the surprint method as described below.

1) Exposure is performed by irradiating with actinic rays in a state where a color separation mask is superposed on a photosensitive transfer sheet (exposure step).

2) By treating this transfer sheet with a developer, a decomposed image is formed on the release layer (developing step).

3) Using another photosensitive transfer sheet, the first and second steps are repeated to obtain a two-color to four-color color proofing sheet.

4) A color proofing sheet having a decomposed image of the first color is superposed such that the decomposed image side is in contact with the image receiving layer of the image receiving sheet comprising the support and the photopolymerizable image receiving layer, and then heated and pressed. And adhere. The decomposed image is thermocompression bonded while embedded in the uncured image receiving layer. Next, the support (temporary support) of the transfer sheet is peeled off and the image is transferred together with the release layer (transfer step).

Further, by performing the same operation using the remaining color proofing sheets, the separated images of the second and subsequent colors are sequentially transferred onto the same image receiving sheet while being aligned with the separated images of the first color. On the image receiving sheet, a two-color to four-color separated image is transferred and formed in a state of being embedded in the image receiving layer.

5) The image receiving sheet to which the multicolor image has been transferred is superposed on the white paper so that the multicolor image side is in contact with the white paper, and then heated and pressed to adhere.

6) The entire surface of the image-receiving sheet is irradiated with actinic rays to photo-cur the photopolymerizable image-receiving layer.

7) By peeling the support (temporary support) of the image receiving sheet, a multicolor image is transferred and formed on the white paper. If desired, fine unevenness may be provided on the surface of the image receiving layer by overlaying a matte film or the like on the image receiving layer and applying heat and pressure.

In the above description, white paper is used as an example of the support on which the decomposed image is finally transferred, but various papers, metals, films, glass, etc. can be used as the support. It is also possible to directly transfer to the final support without using an image receiving sheet.

Furthermore, the two- to four-color color proofing sheets obtained in the above third step can be directly and exactly overlapped and used for color proofing according to the overlay method.

Next, examples and comparative examples of the present invention will be described. However,
The following examples do not limit the invention.

Example 1 A solution having the following composition was prepared as a coating liquid for forming a release layer.

Coating liquid for release layer Alcohol-soluble polyamide 7.2g (CM-8000, viscosity: 23cps, manufactured by Toray Industries, Inc.) Polyhydroxystyrene 1.8g (resin M, average molecular weight: 5,500, manufactured by Maruzen Petroleum Co., Ltd.) Methanol 400g Methylcellosolve 100 g This coating solution was uniformly applied and dried on a polyethylene terephthalate film (support, thickness: 100 μm) to provide a release layer having a dry film thickness of 0.5 μm.

Next, for the purpose of forming an N → P type image, four color photosensitive solutions of yellow (Y), magenta (M), cyan (C) and black (B) are used as coating liquids for forming the photosensitive resin layer. Each composition was prepared so as to have the composition shown in Table 1 below.

Each of these four color photosensitive solutions was applied and dried on four supports provided with a peeling layer to form a photosensitive resin layer having a dry film thickness of 2.4 μm.

Separately, a coating liquid for forming a protective layer having the following composition was prepared, and the coating liquid was applied and dried on each photosensitive resin layer of each color to form a protective layer having a dry film thickness of 1.5 μm.

Coating liquid for protective layer Polyvinyl alcohol 60g (GL-05, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) Water 970g Methanol 30g In this way, four colors consisting of support, release layer, photosensitive resin layer and protective layer To produce a photosensitive transfer sheet (negative colored photosensitive sheet).

[Example 2] A four-color photosensitive transfer sheet was produced by performing the same processing as in Example 1 except that the composition of the release layer coating liquid was changed to the following composition. .

Coating liquid for release layer Alcohol-soluble polyamide 7.2g (CM-8000, viscosity: 23cps, manufactured by Toray Industries, Inc.) Methyl methacrylate / hydroxystyrene copolymer (molar ratio: 1/9, molecular weight: 20,000) 1.8g Methanol 400g Methyl Cellosolve 100 g [Comparative Example 1] A four-color photosensitive transfer sheet was obtained by performing the same operation as in Example 1 except that the composition of the release layer coating liquid was changed to the following composition. Manufactured.

Release Layer Coating Liquid Alcohol-soluble polyamide 9.0 g (CM-8000, viscosity: 23 cps, manufactured by Toray Industries, Inc.) Methanol 400 g Methyl Cellosolve 100 g [Comparative Example 2] In Example 1, the composition of the release layer coating liquid was as follows. A four-color photosensitive transfer sheet was manufactured by performing the same treatment as in Example 1 except that the above procedure was changed.

Release Layer Coating Solution Polyhydroxystyrene 9.0 g (Resin M, average molecular weight: 5,500, manufactured by Maruzen Petroleum Co., Ltd.) Methanol 400 g Methyl Cellosolve 100 g [Comparative Example 3] In Example 1, the composition of the release layer coating solution is as follows. A four-color photosensitive transfer sheet was manufactured by performing the same treatment as in the method of Example 1 except that the composition was changed.

Coating liquid for release layer Alcohol-soluble polyamide 7.2g (CM-8000, viscosity: 23cps, manufactured by Toray Industries, Inc.) Styrene-maleic acid copolymer 1.8g (Oxylac SH-101, manufactured by Nippon Shokubai Chemical Co., Ltd.) Methanol 400 g Methyl cellosolve 100 g [Comparative Example 4] In Example 1, four-color photosensitivity was obtained by performing the same treatment as in Example 1 except that the composition of the release layer coating solution was changed to the following composition. A transfer sheet was manufactured.

Coating liquid for release layer Alcohol-soluble polyimide 7.2 g (CM-8000, viscosity: 23 cps, manufactured by Toray Industries, Inc.) Copoly (vinyl acetate / vinyl stearate) 1.8 g Methanol 400 g Methylcellosolove 100 g [Comparative Example 5] In Example 1, A four-color photosensitive transfer sheet was produced by the same treatment as in Example 1 except that the composition of the release layer coating liquid was changed to the following composition.

Coating liquid for release layer Alcohol-soluble polyimide 7.2g (CM-8000, viscosity: 23cps, manufactured by Toray Industries, Inc.) Copoly (vinyl chloride / vinyl acetate / maleic anhydride) 1.8g Methanol 400g Methylcellosolove 100g [Evaluation of photosensitive transfer sheet With respect to each of the obtained four-color photosensitive transfer sheets, an image transfer characteristic test and a color material fog test described below were performed.

(1) Fog test for color materials The photosensitive transfer sheets for each of the four colors were overlaid with the corresponding masks using the register pins, and then transferred with a 2kw ultra-high pressure mercury lamp.
Image exposure was performed from a distance of 0 cm. The exposed transfer sheet was developed with a developer having the following composition at a temperature of 35 ° C. for 20 to 25 seconds to obtain a four-color color proofing sheet.

Developer Na ₂ CO ₃ 15 g Butylcellosolve 3 g Water 1 Each of the obtained color proofing sheets was observed for the degree of stain by the pigment in the non-image area (release layer),
The following three grades A to C were used for evaluation.

A: Almost no stain was caused by the pigment.

B: Some stain was caused by the pigment.

C: A lot of stains were generated by the pigment.

(2) Image transfer characteristic test First, the black color proofing sheet obtained in the color material fog test was accurately measured using a register pin on the image receiving sheet so that the image side was in contact with the photopolymerizable image receiving layer of the image receiving sheet. Then, using a laminator (Fast Laminator 8B-550-80, made by Taisei Corporation), pressure 2 bar, roller temperature 110 ° C, laminator speed 6
Lamination was performed under the condition of 0 cm / min. Only the support of the color proofing sheet was peeled off from the release layer, and the black image was transferred onto the image receiving sheet. Then, the same operation was repeated for the remaining three color proofing sheets to obtain an image receiving sheet on which halftone images were transferred and formed in the order of black, cyan, magenta and yellow.

Each of the above transfer steps is carried out in an atmosphere of (I) temperature of 25 ° C. and humidity of 40% RH (II) in an atmosphere of temperature of 30 ° C. and humidity of 80% RH to improve the peelability between the support and the release layer. It was measured.
The evaluation was performed in the following four stages A to D.

A: The peeling between the peeling layer and the support was good.

B: Peeling between the release layer and the support had no practical problem.

C: Peeling between the peeling layer and the support had some trouble in practical use.

D: The peeling between the peeling layer and the support was incomplete.

The image receiving sheet used in the above is manufactured as follows.

Polyethylene terephthalate film (support, thickness: 1
00 μm) and prepare a coating solution having the following composition, and then apply this coating solution evenly on a support and dry it.
By providing a 20 μm photopolymerizable image receiving layer, an image receiving sheet comprising a support and the photopolymerizable image receiving layer was obtained.

Photopolymerizable image-receptive layer coating liquid Methyl methacrylate polymer 85g (Average molecular weight: 100,000) Vinyl chloride / vinyl acetate / vinyl alcohol copolymer (S-REC A, Sekisui Chemical Co., Ltd.) 8g Benzoin methyl ether 5g Paramethoxy Phenol 0.09 g Trimethylolpropane trimethacrylate 60 g Metal ethyl ketone 300 g Furthermore, a color test sheet for the surprint system was prepared as follows using the image receiving sheet having the above four-color transfer image.

An image-receiving sheet having a four-color transfer image was superposed on white art paper so that the image-receiving layer side was in contact, and then laminated under the same conditions as described above. The art paper was exposed through the support of the image receiving sheet with a 2 kw ultra-high pressure mercury lamp at a distance of 50 cm, and then the support of the image receiving sheet was peeled off. In this way, an art paper (color test sheet) provided with an image receiving layer having a four-color image was obtained.

The results obtained are shown in Table 2.

As is clear from the results shown in Table 1, when the color proofing sheet was prepared using the photosensitive transfer sheet of the present invention (Examples 1 and 2), the low humidity condition (I) was used.
The image transfer was good under both the high humidity condition (II) and the pigment fog was hardly generated in the non-image area. On the other hand, a known photosensitive transfer sheet (Comparative Example 1,
3) and a photosensitive transfer sheet for comparison (Comparative Example 2)
In the case of high humidity, the adhesion between the support and the peeling layer was too strong and transfer failure occurred. In addition, pigment fog was generated in the non-image area, which was not practical. The polymer to be combined with the alcohol-soluble polyamide is copoly (vinyl acetate / vinyl stearate) or copoly (vinyl acetate / vinyl stearate / anhydrous) which is a general binder resin other than the hydroxystyrene polymer. When it is replaced with maleic acid) (Comparative Examples 4 and 5),
Although there were no major problems under low humidity conditions, under high humidity conditions, peeling between the release layer and the support caused problems, and some pigment fog also occurred.

Furthermore, the color test sheet for the surprint system obtained using the photosensitive transfer sheet of the present invention had a clear image.

Claims (5)

[Claims] 1. A photosensitive transfer sheet having a support, a release layer made of an organic polymer and a photosensitive resin layer in this order, wherein the release layer comprises an alcohol-soluble polyamide and a hydroxystyrene polymer at a ratio of 4: 6 to. A photosensitive transfer sheet comprising a mixture having a weight mixing ratio in the range of 9: 1. 2. The photosensitive transfer sheet according to claim 1, wherein the alcohol-soluble polyamide has a viscosity in the range of 0.2 to 70 cps. 3. The hydroxystyrene-based polymer is at least one compound selected from the group consisting of polyhydroxystyrene, a copolymer of hydroxystyrene and a vinyl-based compound, and derivatives thereof. The photosensitive transfer sheet according to the item. 4. The photosensitive transfer sheet according to claim 3, wherein the molecular weight of the hydroxystyrene polymer is in the range of 800 to 10,000. 5. The photosensitive transfer sheet according to claim 1, wherein the support is made of polyethylene terephthalate.