JP2913469B2 - Method for producing multicolor images and photosensitive material therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to photosensitive, especially photopolymerizable, materials for producing color proof sheets for multicolor printing. The invention further relates to a color proofing method wherein a multicolor image is produced from a plurality of primary color images registered on an image receiving material. A primary color image is formed by laminating one primary color photopolymerizable layer on an image receiving material and exposing under each color separation film,
The image is developed by peeling off the support sheet for the photopolymerizable layer along with the non-image areas, and is made by repeating the same process with a photopolymerizable layer of another primary color.

[0002] Such color proofing methods and materials therefor are known from US Pat. Nos. 4,895,787 and 5,049,476. This material consists of a transparent support sheet, the surface of which is preferably pretreated for adhesion promotion, the photopolymerizable layer comprises dyes or pigments of the primary colors of the multicolor printing, and is thermally active on the photopolymerizable layer. Includes a possible adhesion promoting layer. After lamination to the image receiving material and exposure through the support sheet, the material is developed by separately peeling off the support sheet and the image receiving material. The exposed areas of the light-sensitive color layer adhere to the support sheet, while the unexposed areas remain on the image-receiving material with the complete adhesion-promoting layer. Thus, the method works positively, ie, produces a positive image of the original on the image receiving material.

This processing method has the great advantage that the development step does not require any alkaline or acidic solutions and does not require any organic solvents to remove their waste.
The disadvantage of this method is that the thermoplastic adhesion promoting layer has a tendency to stick when the material is stacked or rolled.
As a result, the adhesion-promoting layer adheres very strongly to the back of the adjacent sheet, especially when stored for long periods at high temperatures, so that it can no longer be separated therefrom without damage. In addition, when these sheets are placed on top during lamination, aeration is formed which no longer disappears automatically due to the tendency of the layers to stick, creating problems to deal with.

[0004] US-A 4,889,787 discloses photosensitive materials for producing color proof sheets based on photosensitive diazo oxides, which contain an adhesion-promoting layer containing a silica pigment. The pigments used therefor are intended to prevent blocking of the adhesion promoting layer and have an average particle size exceeding the thickness of the adhesion promoting layer.

[0005] AU-A 31796/89 discloses the use of polymer particles in a solvent developable diazo resin system to prevent blocking of the thermally active adhesion-promoting layer. Also exceeds the thickness of the adhesion promoting layer. The silica pigments of very small average particle size (less than 0.05 μm) which are also used in this application as negative examples are specifically described as completely ineffective for the antiblocking effect.

[0006] On the other hand, EP-A 0556732
Is the condition that the average particle size of the pigment must be smaller than the thickness of the adhesion promoting layer to achieve the optimal effect,
The addition of a pigment to the adhesion promoting layer to reduce blocking is described for systems as described herein.
However, this application also teaches that pigments having a very small average particle size (less than 1% of the thickness of the adhesion promoting layer or less than 0.05 μm) do not prevent blocking of the adhesion promoting layer.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to have no tendency to develop sticking or air entrainment in laminating and peeling treatments, in which case, for example, inserting an intermediate paper or film to prevent sticking. It is an object of the present invention to provide a color proofing method and a photosensitive material as described at the outset, in which the material can be stored and wound up on a roll without the need for such means.

[0008]

The present invention provides the following A) and B).
Provided is a photosensitive material for producing a color proof sheet for multicolor printing, including: A) a transparent flexible polymer support sheet; B) B1), B2), B3) and B4) below. B1) a polymer binder; B2) a radically polymerizable compound; B3) a compound capable of initiating the polymerization of (B2) under the action of actinic radiation; B4) a primary color dye for multicolor printing Or a pigment; C) a thermoplastic adhesion promoting layer on the photosensitive layer.

The material according to the invention comprises a colorless, transparent or white pigment whose thermoplastic adhesion-promoting layer has an average particle size of less than 1% of the layer thickness and not exceeding 0.05 μm.
5% by weight, characterized in that the material produced has a coefficient of slip friction of less than 0.5.

The suitability of pigments of this size for providing an anti-blocking effect is quite surprising, in stark contrast to the prior art.

From another aspect, the invention relates to a method of laminating a light-sensitive material of the composition indicated above on an image-receiving material with an adhesion-promoting layer under pressure, and before or after lamination under color separation through a support sheet. The support sheet is laminated and the support sheet is peeled off from the image receiving material together with the exposed area of the photopolymerizable layer after the exposure, and the steps of lamination, exposure and peeling are repeated with at least one further color separation, and the exposure Provided is a method for producing a multicolor image characterized in that it is performed in register with the original primary color image created on the receiving material.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The adhesion-promoting layer of the material according to the invention has, as an essential feature, a certain range of particle size, a colorless color present in a certain range which cannot be seen in the transparent polymer layer. , Transparent or white pigments.

The pigments can be inorganic or organic in nature and must be insoluble in the coating solvent used for the adhesion-promoting layer. Since the solvent used is preferably water or a mixture consisting mainly of water, a number of water-insoluble substances are suitable for use as pigments. For example, silica, alumina, silicates, phosphates, borates and other inorganic salts or oxides. Also suitable are organic polymers such as polyethylene, polypropylene, polyester, polycarbonate, phenolic resins and other water-insoluble substances. Generally, inorganic pigments are preferred.

[0014] The pigment is used in an amount of 0.
It is present in a proportion of from 0.5 to 2.5% by weight. Preferably it is present in a proportion of from 0.1 to 1.5% by weight, especially from 0.2 to 1.0% by weight.

The average particle size of the pigment is 1% of the thickness of the adhesion promoting layer.
And should not exceed a size of 0.05 μm. The thickness of the adhesion-promoting layer is usually described as the coating weight and ranges from ^{2 to} 30 g / m2. For a density of about 1, this corresponds to 2 to 30 μm. Therefore the particle size is between 0.005 and 0.050 μm, preferably between 0.05 and 0.050 μm.
10 to 0.045 μm.

Although the prior art does not attribute the anti-blocking effect to particles of this order of magnitude, surprisingly, in our system, at a certain dosage, only particles of this order of magnitude Can provide an anti-blocking effect, so that after production the color proof material can be wound up without intermediate paper or film and stored on rolls even under pressure without other disadvantageous mechanical properties I understood.

The amount used must be selected so that the material produced has a coefficient of slip friction of less than 0.5, preferably less than 0.3.

The pigment should be readily dispersible in the usual aqueous solutions used for coating.

The adhesion-promoting layer is applied directly to the photopolymerizable layer from a solvent or solvent mixture that does not even dissolve the photopolymerizable layer at first, and is dried. Suitable solvents which do not initially dissolve the color layer are water or a mixture consisting mainly of water and saturated hydrocarbons. Many polymers can be applied from aqueous dispersions; however, application from solution is preferred. Suitable for this purpose are, for example, acidic groups (eg carboxy groups)
Is a salt of a polymer having A preferred example is a vinyl acetate / crotonic acid copolymer (registered trademark Mowilith Ct5)
Aqueous alkaline solution of Other suitable polymers are polyvinyl acetate or polyacrylate dispersions. The polymer should have a softening temperature in the range of 40-200C, preferably 60-120C, and a Tg value preferably in the range of 20-60C. Like the thermoplastic polymer, the adhesion promoting layer may further include a plasticizer, a residual solvent, a planarizing agent, a lubricant, an antistatic agent, an optical brightener and / or a UV absorber. Its coating weight in the dry state is usually 2 to 30, preferably 3 to 15 g / m ² . A preferred adhesion promoting layer is U
It is also described in SA-48995787 and EP-A-525624.

The photopolymerizable layer of the material of the present invention contains as essential components a polymer binder, a radically polymerizable compound, a photoinitiator and a dye or pigment in the primary colors of multicolor printing. An example of a photopolymerizable layer of this general composition is described in US-A 48957.
87, which is incorporated herein by reference.

Suitable photoinitiators are various types of compounds or combinations of compounds known for this purpose. For example, there are benzoin ether, benzyl ketal, polycyclic quinone, benzophenone derivative, triarylimidazolyl dimer, and photosensitive trihalomethyl compound (for example, trichloromethyl-s-triazine). Preferably 2, as described in US-A 3765898
3-bisarylquinoxaline and 2-aryl-4,
6-Bistrichloromethyl-s-triazine. The amount of photoinitiator or photoinitiator combination is generally between 1 and 25, preferably between 5 and 15% by weight.

The polymeric binder is intended to provide homogeneity and strength on the layer. Suitable binders are styrene / maleic anhydride copolymers, acrylic ester polymers and copolymers, polyamides, polyvinylpyrrolidone, cellulose derivatives (eg, cellulose esters and ethers),
Phenol resins, polyvinyl esters, polyvinyl acetals such as polyvinyl butyral, polyvinyl propional or polyvinyl formal. The proportion of binder is generally from 15 to 70, preferably from 20 to 50% by weight, based on the weight of the solid layer.

The polymerizable compound contains at least one, and preferably at least two, terminal free radical polymerizable double bonds and is not gaseous at temperatures below 100 ° C. and normal pressure. Preferred are amides and esters of acrylic acid and methacrylic acid. In particular, esters having polyhydric alcohols are advantageously used. For example, di-, tri-, tetra- and polyethylene glycol di (meth) acrylates, oligo- and polypropylene glycol di (meth) acrylates, 1,4-butanediol di (meth)
There are acrylates, trimethylolpropane and trimethylolethanedi- and tri (meth) acrylates, pentaerythritol tri- and tetraacrylate or -methacrylate, dipentaerythritol tetra-, penta- and hexa (meth) acrylate. The proportion of polymerizable compounds is generally between 15 and 70, preferably between 20 and 60% by weight.

In a preferred use of the novel materials for color proofing in multicolor printing, dyes and color pigments are used to make them the primary colors of multicolor printing, cyan (blue-green), magenta (purple), yellow and black. Selected to be equivalent.
Pigments are generally preferred. For example, Permanent Yellow G
(CI 21 095), Permanent Yellow GR (CI
21 100), Permanent Yellow DHG (CI 21 09
0), Permanent Rubine L6B (CI 15 850: 1), P
ermanent Pink F3B (CI 12 433), registered trademark Hos
taperm Pink E (CI 73 915), registered trademark Hostape
rm Reddish VioletER (CI 46 500), Permanent
Carmine FBB (CI 12 485), registered trademark Hostape
rm Blue B2G (CI 74 160), registered trademark Hostaperm
Blue A2R (CI 74 160) and registered trademark Printex
25 (carbon black). If necessary, the pigments can be blended to obtain the desired hue.
The inorganic or organic pigment is generally dispersed or pasted in a suitable solvent with a portion of the binder. The average particle size is generally less than 1 μm.

The proportion of dyes or pigments is generally between 8 and 40, preferably between 12 and 30% by weight.

The photopolymerizable layer comprises additional components such as hydrogen donors, polymerization initiators, plasticizers, residual solvents, surfactants, planarizing agents, lubricants, antistatic agents, inert fillers, optical brighteners and And / or may include UV absorbers. It is generally 0.2 to 5, preferably has a coating weight of 0.3 to 3 g / m ^2.

The support sheet used is a transparent, flexible, dimensionally stable sheet made of plastic (eg, polyester, polycarbonate, etc.). Particularly preferred are polyester sheets, especially biaxially stretched and heat set sheets of, for example, polyethylene terephthalate. They should be dimensionally maintained at the required lamination temperature, i.e., about 60-150C. Their thickness is generally between 10 and 200, preferably 2
5 to 80 μm. The support sheet may advantageously be provided with an adhesion-promoting pretreatment on one or both sides and may have a smooth or rough / matte surface, preferably a smooth surface.

In order to carry out the method of the present invention, the above-mentioned photosensitive material is laminated on an image receiving material with an adhesion promoting layer. The latter can be composed of polymers, polymer-coated specialty papers or ordinary printing papers. Other white or otherwise non-white receiving materials can also be used. Printing papers that are dimensionally stable under laminating conditions are usually preferred. Because it creates a visual impression that is substantially close to the later print. The lamination is advantageously carried out under elevated pressure in an apparatus intended for this purpose. Lamination temperature is usually 6
It is in the range of 0 to 150 ° C, preferably 80 to 130 ° C. Prior to lamination or, preferably, after lamination, the photopolymerizable layer is subjected to imagewise exposure in a conventional manner through a support sheet, generally in intimate contact with positive color separation. After lamination and exposure, the support sheet is peeled off by hand or in a suitable device. The peel angle should be at least 90 °, with an angle of 180 ° being particularly preferred. Peeling removes the exposed areas of the photopolymerizable layer with the support sheet, while leaving the unexposed areas with the complete adhesion promoting layer on the image receiving material. This produces a positive primary color image. Each separate color proof sheet is laminated in the manner described above on the previous primary color image, where it is exposed in register and developed by peeling off the support sheet. In this way, the primary color images of cyan (blue-green), magenta (purple), yellow, and black form a complete multicolor image corresponding to the subsequent four-color print. If desired, it is of course possible to use color sheets of special colors.

The multicolor image produced has a bright surface. If desired, the surface can be made matte, for example by laminating on a sheet with a rough surface and peeling it off again. The surface of the produced proof image can be protected from sticking or being damaged at high temperature by a protective layer.

[0030]

The present invention will be described by the following examples. All percentages and proportions are by weight. Examples 1 and 2 are comparative examples, and Examples 3 to 7 show the effects of the present invention.

Example 1 (Comparative Example 1) The following solution was applied to a 50 μm thick, biaxially stretched, heat-set polyester sheet (Melinex 505®) pretreated on both sides for adhesion promotion: Cyan magenta yellow black dipentaerythritol pentaacrylate 19.9 25.0 21.6 19.9 2,3-bis- (4-methoxyphenyl) quinoxaline 5.1 6.1 5.4 5.3 Polyvinyl formal (registered trademark Formvar 12/85) 16.3 23.0 18.4 14.2 80 weight in polyether part % Ethylene oxide and 20% by weight propylene oxide copolymer of polyether-modified polysiloxane 0.2 0.2 0.2 0.2 Viscosity 240 cSt / 25 ° C, molecular weight about 6500 Hostaperm Blue B2G (CI 74 160) 9.7 Permanent Red FBB (CI 12 485) 12.9 Permanent Yellow GR (CI 21 100) 8.6 Carbon black (registered trademark) Printex 25) 13.6 Tetrahydrofuran 398.6 363.9 382.4 378.8 4-hydroxy-4-methyl-2-pentanone 113.9 121.3 124.3 123.1 1-methoxy-2-propanol 360.6 326.5 353.7 331.5 γ- butyrolactone 75.9 121.3 86.0 113.6

The pigment was dispersed in the binder and part of the butyrolactone. The average particle size was 200 nm or less.

The coated sheet was dried in a drying duct at a temperature of up to 110 ° C. 0.6-0.8g coating weight
/ M ² .

The following adhesion promoting layer solution was applied on the dried photopolymerizable layer: vinyl acetate / crotonic acid copolymer 95: 5 50.0 parts Pyrolytic silica (average particle size 3 μm) 0.08 parts Water 252 Part ethanol 24.0 parts aqueous ammonia, 25% concentration 5.0 parts

The coated sheet was dried at a temperature of 100 ° C. in a drying duct. The coating weight was 6.5 g / cm ² .

When the sheets were laminated, there was no air entrapment or holes in the image area after the Melinex® sheet was peeled off.

Roll the photosensitive sheet without intermediate material (ie, layer on the sheet) (core 300 mm winding tension 400 N)
Stored at 25 ° C above.

After about 4 days, the stored material could no longer be satisfactorily unwound from the roll. They were sticky.

Example 2 (Comparative Example 2) On the photosensitive layer prepared according to Example 1, an adhesive layer of the following composition was applied: Vinyl acetate / crotonic acid copolymer 95: 5 50.0 parts Heat Decomposed silica (average particle size: 3 μm) 0.16 parts Water 252 parts Ethanol 24.0 parts Aqueous ammonia, 25% concentration 5.0 parts

The coated sheet was dried at a temperature of 100 ° C. in a drying duct. The coating weight was 6.5 g / m ² .

Upon lamination of the sheets, numerous pinholes were found in the image area after the Melinex® sheet was peeled off.

Example 3 An adhesive layer of the following composition was applied on the photosensitive layer prepared according to Example 1: vinyl acetate / crotonic acid copolymer 95: 5 50.0 parts pyrogenic silica (average particle size) 0.08 parts Water 252 parts Ethanol 24.0 parts Aqueous ammonia, 25% concentration 5.0 parts

The coated sheet was dried at a temperature of 100 ° C. in a drying duct. The coating weight was 6.5 g / m ² .

When the sheets were laminated, there was no air entrapment or holes in the image area after the Melinex® sheet was peeled off.

Roll the photosensitive sheet without intermediate material (ie, layer on the sheet) (core 300 mm winding tension 400 N)
Stored at 25 ° C above.

After about 6 days, the stored material could no longer be satisfactorily unwound from the roll. They were sticky.

Example 4 An adhesive layer having the following composition was applied on the photosensitive layer prepared according to Example 1. Vinyl acetate / crotonic acid copolymer 95: 5 50.0 parts Pyrolytic silica (average particle size: 15 nm) 0.08 parts Water 252 parts Ethanol 24.0 parts Aqueous ammonia, 25% concentration 5.0 parts

The coated sheet was dried at a temperature of 100 ° C. in a drying duct. The coating weight was 6.5 g / m ² .

When the sheets were laminated, there was no air entrapment or holes in the image area after the Melinex® sheet was peeled off.

Roll the photosensitive sheet without intermediate material (that is, the layer on the sheet) (core 300 mm winding tension 400 N)
Stored at 25 ° C above.

After about 6 days, the stored material could no longer be satisfactorily unwound from the roll. They were sticky.

Example 5 An adhesive layer of the following composition was applied on the photosensitive layer prepared according to Example 1: vinyl acetate / crotonic acid copolymer 95: 5 50.0 parts pyrogenic silica (average particle size) Diameter 40 nm) 0.16 parts Water 252 parts Ethanol 24.0 parts Aqueous ammonia, 25% concentration 5.0 parts

The coated sheet was dried at a temperature of 100 ° C. in a drying duct. The coating weight was 6.5 g / m ² .

When the sheets were laminated, there was no air entrapment or holes in the image area after the Melinex® sheet was peeled off.

Roll the photosensitive sheet without any intermediate material (ie, the layer on the sheet) (core 300 mm winding tension 400 N)
Stored at 25 ° C above.

After about 20 days, the stored material could not be satisfactorily unwound from the roll. They were sticky.

Example 6 An adhesive layer of the following composition was applied on the photosensitive layer prepared according to Example 1: vinyl acetate / crotonic acid copolymer 95: 5 50.0 parts pyrogenic silica (average particle size) Diameter 15 nm) 0.16 parts Water 252 parts Ethanol 24.0 parts Aqueous ammonia, 25% concentration 5.0 parts

The coated sheet was dried at a temperature of 100 ° C. in a drying duct. The coating weight was 6.5 g / m ² .

When the sheets were laminated, there was no air entrapment or holes in the image area after the Melinex® sheet was peeled off.

Roll the photosensitive sheet without intermediate material (that is, the layer on the sheet) (core 300 mm winding tension 400 N)
Stored at 25 ° C above.

After about 20 days, the stored material could not be satisfactorily unwound from the roll. They were sticky.

Example 7 An adhesive layer of the following composition was applied on the photosensitive layer prepared according to Example 1: vinyl acetate / crotonic acid copolymer 95: 5 50.0 parts pyrogenic silica (average particle size) Diameter 15 nm) 0.16 parts Water 252 parts Ethanol 24.0 parts Aqueous ammonia, 25% concentration 5.0 parts

The coated sheet was dried at a temperature of 100 ° C. in a drying duct. The coating weight was 3 g / m ² .

When the sheets were laminated, there was no air mixing or holes in the image area after the Melinex® sheet was peeled off.

Roll the photosensitive sheet without intermediate material (ie, layer on the sheet) (core 300 mm winding tension 400 N)
Stored at 25 ° C above.

After about 20 days, the stored material could not be satisfactorily unwound from the roll. They were sticky.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI G03F 7/34 G03F 7/34 (72) Inventor Dieter Bodenheimer Federal Republic of Germany Day-65326 Arlbergen, Sonnenhank 34 (72) Inventor Dieter-Mall Federal Republic of Germany Day-55437 Appenheim, Form, Westerberg 20 (56) References JP-A-6-89029 (JP, A) JP-A-5-257271 (JP, A) JP-A-2- 66547 (JP, A) JP-A-6-51500 (JP, A) JP-A-2-12252 (JP, A) JP-A-3-123354 (JP, A) JP-A-7-72632 (JP, A) JP-A-63-298242 (JP, A) JP-A-6-11610 (JP, A) JP-A-53-11719 (JP, A) JP-A-64-19352 (JP, A) -236690 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03F 7/004 G03F 7/027 G03F 7/11 G03F 7/34

Claims (11)

(57) [Claims] 1. A photosensitive material for producing a color proof sheet for multicolor printing including the following A), B) and C): A) a transparent flexible polymer support sheet, B) the following B1), B2), a photopolymerizable layer containing B3) and B4): B1) a polymer binder, B2) a radically polymerizable compound, B3) a compound capable of initiating the polymerization of (B2) under the action of actinic radiation, B4 C) a thermoplastic adhesion promoting layer on the photosensitive layer having a coating weight of ^{2 to} 30 g / m ² , wherein the thermoplastic adhesion promoting layer comprises 1% of the layer thickness A ready-produced material containing 0.05 to 2.5% by weight of a colorless, transparent or white pigment having a smaller average particle size and a slip friction coefficient of less than 0.5
A photosensitive material having: 2. The photosensitive material according to claim 1, wherein the average particle size of the pigment in the adhesion promoting layer is 0.010 to 0.045 μm. 3. The photosensitive material according to claim 1, wherein the pigment in the adhesion promoting layer is an inorganic pigment. 4. The thermoplastic adhesion-promoting layer contains 0.2 to 1.0% by weight of a pigment.
The photosensitive material as described in the above. 5. The photosensitive material according to claim 1, wherein the produced material has a coefficient of slip friction of less than 0.3. 6. The coating weight of the adhesion promoting layer is 3 to 15 g / m.
^{2. The method according} to claim 1, wherein the number is 2.
The photosensitive material as described in the above. 7. The photosensitive material according to claim 1, wherein the thermoplastic adhesion promoting layer has a glass transition temperature Tg of 20 to 100 ° C. 8. The photosensitive material according to claim 1, wherein the radically polymerizable compound contains at least two polymerizable groups. 9. The photosensitive material according to claim 1, wherein the radically polymerizable compound is an acrylic or methacrylic ester. 10. The photopolymerizable layer having a coating weight of 0.2 to 5 g / m ² .
The photosensitive material according to 4, 5, 6, 7, 8 or 9. 11. The method of claim 1, 2, 3, 4, 5, 6, 7,
Laminating a photosensitive material of the composition shown in 8, 9 or 10 with an adhesion-promoting layer under pressure on the image-receiving material and subjecting it to image-wise exposure through a support sheet under color separation, before or after lamination,
The support sheet was peeled from the image receiving material together with the exposed areas of the photopolymerizable layer after lamination and exposure, and the steps of lamination, exposure and release were repeated with at least one additional color separation, and exposure was created on the image receiving material. A method for producing a multicolor image, characterized in that it is performed in register with the original primary color image.