JP2735481B2 - Photopolymerizable printing layers for flexographic printing plates - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a photopolymerizable recording material and a method for using the same. More particularly, the present invention provides a photopolymerizable dye comprising a polymeric binder, an addition polymerizable monomer, and a dye comprising a reaction product of a phthalocyanine polysulfonyl metal complex and an alkylamine having at least 11 carbon atoms. The present invention relates to a recording material and a printing plate containing this dye for flexographic printing.

[0002]

2. Description of the Related Art A photopolymerizable recording material is used for producing a printing plate, particularly a plate for flexographic printing, and a printing surface thereof is formed by exposing a photosensitive layer to an image and then removing an unexposed area of the layer. It is made by doing. Examples of such recording materials are described in DE-C 2215 090 (Chen, U.S.A.
S. Patent No. 4,323,636); Nakamura et al., US Patent No. 4,323,636.
No. 266,005; Heinz No. 4,320,188; Roos No.
No. 4,126,466; and Heinz et al., No. 4,430,417.

[0003] Such photopolymerizable printing plates usually comprise (a) a support, (b) an optional adhesive or other auxiliary layer,
(C) at least one polymeric binder, at least one addition polymerizable ethylenically unsaturated monomer,
And a photopolymerizable layer containing a photoinitiator, and (d) a cover layer. Usually, between the photopolymerizable layer and the cover layer, a flexible, tear resistant polymer film is removed which is removed during solvent washout development after exposure. The polymer layer allows for the placement of the printing plate without exposure negatives.

One preferred method of making such a multilayer photopolymerizable printing plate is to feed a pre-extruded photopolymerizable composition into the nip of a calender and to provide a support between the support and the cover element. It is calendered to form a photopolymerizable layer. EP-B No. 00 84 851
(Gruetzmacher et al., US Pat. Nos. 4,427,759 and 4,460,675) disclose an elastomeric binder and optionally a second binder between a flexible tear resistant polymer film and a photopolymerizable layer. Figure 3 illustrates a method for making a multilayer photopolymerizable printing plate having an elastomeric layer containing a dye, one or more monomers, and a photoinitiator.

[0005] Such printing plates usually contain in one of the recording layers a dye such as, for example, acid blue (CI 13390) or copper phthalocyanine (CI 74 160). DE-C 1905012 (US Pat. No. 3,674,4)
No. 94) discloses soluble copper phthalocyanine dyes, including isohexylamine salts of copper phthalocyanine dyes (CI 74 350), and other uses.

However, the dyes currently used have (a) insufficient stability during the production of printing plates, (b)
It has disadvantages such as being washed out during development and (c) low latitude in printing plate processing. Thus, the present invention describes a photopolymerizable recording material suitable for the preparation of printing plates, in particular flexographic printing plates, having a high color contrast between the printed and non-printed areas.

[0007]

DETAILED DESCRIPTION OF THE INVENTION Surprisingly or unexpectedly, it has been discovered that (a) at least one polymeric binder, (b) at least one addition-polymerizable ethylenically unsaturated monomer, and (c) A photopolymerizable recording material containing a phthalocyanine polysulfonyl chloride metal complex and a dye consisting of a reaction product of an alkylamine having at least 11 carbon atoms has a high color contrast between a printed area and a non-printed area. It has been found to make printing plates with.

A particular advantage of the use of this dye in the elements of the invention is that it is not washed out of the recording layer during development of the imagewise exposed printing plate, and therefore the printed and non-printed areas of the plate Higher color contrast is guaranteed during the process. In addition, the dyes used in the elements of the invention do not reduce the processing latitude of the printing plate and can be used there in all current plate making methods.

The development-resistant dye is the reaction product of a phthalocyanine polysulfonyl chloride metal complex with an alkylamine having at least 11 carbon atoms in the alkyl chain. Copper phthalocyanine double salts are particularly preferred. Alkylamines are basically those having alkyl groups of 11 to 20 carbon atoms. Isoundecylamine, n-dodecylamine and n-octadecylamine are particularly suitable. The reaction product of copper phthalocyanine sulfonyl chloride and isoundecylamine is known as Color Index No. 74400. The dodecyl and octadecyl products are made by reacting the tetrasodium salt of copper phthalocyanine sulfonic acid with phosphorus pentachloride to the corresponding tetrasulfonyl chloride, and then reacting with the desired amine. Sulfonylamide and ammonium salt of sulfonic acid are usually 2: 1
Generated at a ratio of 〜3: 1.

[0010] The dye used in the element of the present invention includes:
0.05-5.0% by weight; preferably 0.1-1.0% by weight
To the recording layer. The recording layer used in the element of the present invention contains at least one elastomeric binder. For example, DE-C 2215
090 (Chen's US Patent No. 4,323,636); Heinz
U.S. Pat. No. 4,320,188; and Richter et al.
Block copolymers such as those described in S. Patent No. 4,126,919 are suitable. Two thermoplastic blocks,
For example, an elastomeric block between polystyrene,
With polybutadiene or polyisoprene,
ABA block copolymers are preferred. Particularly preferred are linear and radial block copolymers having polyethylene end blocks, such as, for example, polystyrene / polyisoprene / polystyrene, (polystyrene / polybutadiene) ₄ Si or (polystyrene / polyisoprene) ₄ Si.

The average molecular weight of the block copolymer is 80,
Between 000 and 300,000, preferably 100,000
~ 250,000. The proportion of polystyrene is between 10 and 40% by weight; preferably between 15 and 30% by weight. Particular preference is given to (polystyrene / polybutadiene) ₄ Si radial block copolymers having a polystyrene content of 15 to 30% by weight. A 2-block copolymer,
Either those where the boundaries between each polymer block are clear or those which are not clear can be used.

[0012] In addition, the photopolymerizable layer contains at least one addition-polymerizable ethylenically unsaturated monomer.
Suitable monomers for the practice of the present invention are those having one ethylenically unsaturated group and those also having one or more ethylenically unsaturated groups. For example, DE-C 37
Those described in 44443 can be used alone or in combination with other ones. These examples include octyl acrylate, isodecyl acrylate, isodecyl methacrylate, 2-hexyloxyethyl acrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate,
Includes 1,6-hexanediol methacrylate and trimethylolpropane triacrylate.

The photopolymerizable layer may also include o-methylbenzoin,
Includes a photoinitiator or photoinitiator system such as benzophenone, benzyldimethyl ketal, or ethyl-anthraquinone / 4,4'-bis- (dimethylamino) -benzophenone. The photopolymerizable layer can include other additives such as fillers, antioxidants and plasticizers. The photopolymerizable layer generally contains 50 to 95% by weight of a binder, 5 to 30% by weight of a monomer; and 0.5 to 5% by weight of an initiator.

A synthetic resin sheet, for example a polyester sheet, is suitable as a support, which may optionally be coated with an adhesive layer and / or an antihalation layer. Polyethylene terephthalate sheets are preferred. Printing plates prepared from the elements of the present invention can be made by all conventional methods. A preferred method for making such plates is to feed a pre-extruded photopolymerizable composition of the present invention into a nip of a calender and calender between a support and a cover element to form a photopolymerizable layer. It is formed.

[0015] Particularly preferred printing plates of the invention are made by the method described in EP-B-00 84 851. In this way, the pre-extruded photopolymerizable composition is fed into the nip of a calender, and calendered between a cover element and a support consisting of an elastomer layer containing the dye and a cover sheet, and photopolymerized. That is, a conductive layer is formed.

The elastomeric layer comprises, in addition to the dyes described above, at least one elastomeric binder, preferably the thermoplastic block copolymer used in the photopolymerizable layer,
In particular, the aforementioned (polystyrene / polybutadiene) ₄ Si
Contains a radial block copolymer. The elastomer layer may also include an addition polymerizable ethylenically unsaturated monomer. The monomers described above for the photopolymerizable layer are preferred. Initiators, fillers, plasticizers, antioxidants,
Conventional auxiliary materials, such as solvents, etc., can also be added.

The thickness of the elastomer layer is 0.01 to 0.5 m
m, preferably 0.025 to 0.12 mm. This layer can be coated from a solvent such as toluene, acetone, methylene chloride, methyl isobutyl ketone, or a mixture thereof, or can be made directly on a cover sheet, for example, a polyethylene terephthalate sheet, by extrusion coating.

The resulting photopolymerizable printing plate is usually subjected to imagewise exposure through a photographic original after removing the cover sheet. The overall exposure through the support, before or after the imagewise exposure, is optional. The unpolymerized areas of the photopolymerizable layer and the elastomer layer are then washed off with a standard developer. After drying, the resulting printing plate is post-exposed in any order of processing and becomes a non-tacky printing plate surface for chemical post-processing. The following examples illustrate the invention. Percentages are by weight unless otherwise indicated.

Example 1 This example illustrates the preparation of an acid amidoamine salt of copper phthalocyanine tetrasulfonic acid. 98.4 g of tetrasodium salt of copper phthalocyanine tetrasulfonic acid (0.1
Mol) was mixed with 104 g (0.5 mol) of phosphorus pentachloride in a mortar and heated at 105 ° C. for 1 hour. The cooled reaction mixture was washed with ice water, filtered and dried in air. A sample of 10.3 g (0.01 mol) of this product in toluene was each reacted with a twice molar amount of n-decylamine, n-dodecylamine, and n-ontadecylamine. The toluene phase was shaken with water in a separatory funnel and dried over sodium sulfate.

Example 2 To prepare an elastomer layer, the following components were used.
% Solution was prepared:

[Table 1]

To the solution, the dye synthesized in Example 1, the iso-hexylamine product Zapon Blue 806
(CI 74350) and 0.5% each of the iso-undecylamine product Zapon Blue 607 (CI 74400). Each of these solutions polyamide - was coated at a coverage of 350 mg / dm ² on the coating a polyethylene terephthalate sheet. After drying, this of DuPont Cyrel ^R HOF
It was laminated on a flexographic plate. After storage at 60 ° C. for 24 hours, each sample was fully exposed to UV for 12 minutes, and 70% by weight of isoheptyl acetate and 3% of isoheptyl alcohol were used.
Washed off with 0% by weight of the mixture.

[0022] Results: Colored isohexyl amine product pomelo Blue 806 colorless n- decylamine derivative colorless iso-undecyl amine product pomelo Blue 807 Blue n- dodecylamine derivatives blue isooctyl derivatives blue 10 or more strands of a color-containing elastomer layer Only the acid amide derivative of copper phthalocyanine tetrasulfonic acid having a length of was not washed out.

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Claims (4)

(57) [Claims] 1. The method of claim 1 wherein the at least one polymeric binder, at least one addition-polymerizable ethylenically unsaturated monomer, and a dye, wherein the dye has a phthalocyanine polysulfonyl chloride metal complex and at least 11 carbon atoms. A photopolymerizable recording material which is a reaction product with an alkylamine. 2. a) a support; b) at least one photopolymerizable layer containing at least one elastomeric binder, at least one addition-polymerizable ethylenically unsaturated monomer, and a photoinitiator or a photoinitiator system. And c) a cover sheet, wherein the photopolymerizable layer comprises a dye which is a reaction product of a phthalocyanine polysulfonyl chloride metal complex and an alkylamine having at least 11 carbon atoms. Polymerizable printing plate. 3. a) a support; b) a photopolymerizable layer containing at least one elastomeric binder, at least one addition-polymerizable ethylenically unsaturated monomer, and a photoinitiator or a photoinitiator system; c). An elastomer layer containing at least one thermoplastic elastomeric block copolymer; and d) a cover sheet, wherein the elastomer layer comprises a phthalocyanine polysulfonyl chloride metal complex and at least one
A photopolymerizable printing plate comprising a dye which is a reaction product with an alkylamine having one carbon atom. 4. A photopolymerizable composition comprising: (a) at least one elastomeric binder, at least one addition polymerizable ethylenically unsaturated monomer, and a photoinitiator or photoinitiator system in a nip of a calender. And (b) calendering the composition between the support and the multilayer cover element to form a photopolymerizable layer, wherein the multilayer cover element comprises:
(I) an elastomer layer containing at least one thermoplastic block copolymer and a dye which is a reaction product of a phthalocyanine polysulfonyl chloride metal complex and an alkylamine having at least 11 carbon atoms, and (ii) a cover sheet A method for producing a photopolymerizable printing plate, comprising: