JPH0145902B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a photosensitive flexographic printing element. More particularly, the present invention relates to a photosensitive flexographic printing element, the photosensitive layer of which is bonded to a support by an adhesive blend. Photosensitive flexographic printing plates are becoming more important in the printing commerce. A particularly useful composition for the production of such flexographic printing plates contains a butadiene/acrylonitrile polymer optionally containing carboxyl groups, an addition polymerizable ethylenically unsaturated compound, and a photoinitiator. . The composition is formed into layers, which are generally laminated to a flexible support. It has been found that the adhesion of the photosensitive layer to the support is insufficient if no adhesive composition is used to bond the layer to the support. U.S. Patent No. 1 for light-sensitive flexographic layers
No. 4,177,074 (column 9, lines 10-16) discloses that known adhesive compositions can be used to create strong bonds. Other known adhesives are of the polyester type which can be used with hardeners such as isocyanates. Although these adhesives provide improved bonding between the photosensitive layer and the support, they do not reach the desired standard under all conditions. Polyester adhesives containing isocyanate curing agents must be brought into contact with the photosensitive layer almost instantaneously after manufacture. Otherwise, premature curing of the adhesive will result in a poor bond. Adhesive blends are known to be useful in printing plates for bonding photosensitive layers to supports. However, the use of adhesive blends in flexographic printing plates has not previously been known. It is an object of the present invention to provide a photosensitive flexographic element that has excellent adhesion between the photosensitive layer and the support. Another objective is to provide such adhesion under normal conditions using adhesive blends without the need for a curing step. According to the invention, (A) a flexible support and (B) a number average molecular weight of (a) from 20,000 to 75,000 and from 10 to 50, based on the weight of the total composition.
Acrylonitrile content in weight% and 0-15
High molecular weight butadiene/acrylonitrile copolymer with carboxyl content of 55% by weight
90% by weight; (b) non-gaseous ethylene capable of forming high molecular weight polymers by free radical-initiated chain extension addition polymerization containing at least one terminal ethylenic group and compatible with the polymer of (a); (c) 0.001 to 10% by weight of an organic radiation-sensitive free radical-generating system activatable by actinic radiation to initiate polymerization of the unsaturated compound; and between layer (A) and layer (B) (1) a condensation of ethylene glycol, terephthalic acid, isophthalic acid and azelaic acid in a molar ratio of about 6:2:1:3. 0 based on the total resin weight of the adhesive composition and having a number average molecular weight of about 19,000 and a weight average molecular weight of about 37,000.
~78 wt% polyester resin, (2) at 5 wt% solids in methyl ethyl ketone and on Bruckfield spindle #3 at 12 rpm.
0 to 78% by weight of the heat of crystallization based on the total resin weight in the adhesive composition, with a Burckfield viscosity of 100 to 1200 and an adhesive activation temperature in the range of 54 to 63°C. Polyether polyurethane resin, which is a plastic resin, (3) ball-and-ring softening point of 132-145°C, viscosity of 40-60 poise at 210°C, ASTM D
-1708, elongation % of 130 measured at -18°C, 560 measured at 24°C and 100 measured at 60°C,
Measured at -18℃ according to ASTM D-1708
0 to 94 weight percent thermoplastic dimeric acid polyamide resin, based on the total resin weight of the adhesive composition, having a tensile point of break of 4000 psi, 450 psi measured at 24°C, and 170 psi measured at 60°C. polyamide, and (4) ball-and-ring softening point of 150-160°C, viscosity of 28-38 poise at 210°C, ASTM D
-1708, elongation % of 350 measured at -18°C, 250 measured at 24°C and 40 measured at 60°C;
Measured at -18℃ according to ASTM D-1708
0 to 97 weight percent thermoplastic dimeric acid polyamide resin, based on the total resin weight of the adhesive composition, having a tensile point of break of 2200 psi, 360 psi measured at 24°C, and 50 psi measured at 60°C. A photosensitive flexographic element is provided that includes a layer of an adhesive composition that includes a blend of at least two polymers selected from the group consisting of polyamides. The photosensitive composition used in the elements of the invention is adhered to a flexible support, ie a support selected from the group consisting of plastic film and metal. Examples of such supports include:
Polymeric film supports such as polyethylene terephthalate, flame treated polyethylene terephthalate, electron discharge treated polyethylene terephthalate,
Polyimides, such as the films disclosed in U.S. Pat. No. 3,179,634, herein incorporated by reference, and elsewhere, and thin metal supports, such as aluminum, tinned steel (brushed or polished). The polymeric support generally has a thickness in the range of 0.001 inch to 0.007 inch (0.025 to 0.18 mm). Metal supports generally range from 0.010 to 0.0115 inches (0.25 to 0.29 mm) for aluminum;
and 0.008 to 0.010 for tinned steel.
It has a thickness in the inch (0.20-0.25mm) range. In their unexposed state, the photosensitive compositions disclosed herein are developable in aqueous, semi-aqueous basic or solvent solutions depending on the carboxyl content of the pre-polymerized component of the photosensitive composition. .
This photosensitive layer is 0.0005 to 0.250 inches (approximately 0.013
~6.35mm) or thicker. One essential component (a) of the photosensitive elastomer composition
ranges from about 20,000 to about 75,000, preferably about
It is a high molecular weight butadiene/acrylonitrile copolymer having a number average molecular weight ranging from 25,000 to about 50,000. ^-Mn for the polymers _described herein can be determined by gel permeation chromatography using butadiene standards. The acrylonitrile content of the polymer varies from about 10 to about 50%, preferably from about 15 to about 40% by weight. Optionally, the copolymer also has a carboxyl content of 0 to about 15% by weight. If the copolymer contains carboxyl groups, its carboxyl content preferably ranges from about 1 to about 15%, preferably from about 2 to about 10% by weight. The copolymer is present in an amount of about 55 to 90% by weight, and preferably about 60 to about 75% by weight, based on the total weight of the composition. At least about 55% by weight copolymer is required to provide sufficient flexibility and physical integrity to the photosensitive element, particularly for flexographic plates. Carboxyl groups can be incorporated into high molecular weight copolymers by adding to the polymerization process carboxyl-containing monomers such as acrylic or methacrylic acid or monomers convertible to carboxyl-containing groups such as maleic anhydride or methyl methacrylate. can be done. Such polymers are available from several sources such as "Hycar" from BF Goodrich Chemical Company.
It is commercially available under the trade name. Other essential components of the photosensitive composition of the invention
(b) is a non-gaseous ethylenically unsaturated compound containing at least one terminal ethylenic group. The compound should be capable of forming a high molecular weight polymer by free radical initiated chain extension addition polymerization and should be compatible with the high molecular weight polymer of (a) above. One group of suitable ethylenically unsaturated compounds includes unsaturated esters of alcohols, especially α-methylenecarboxylic acids and substituted α-
Such esters of methylene carboxylic acids, more particularly alkylene polyols and such esters of polyalkylene polyols, and most especially alkylene polyols having from 2 to 15 carbon atoms or from 1 to 10 ether linkages. Mention may be made of alkylene polyol di- and triacrylates and polyalkylene polyol di- and triacrylates made from polyalkylene ether polyols or glycols. The following specific compounds are other examples of this group. Ethylene glycol diacrylate, diethylene glycol diacrylate, glycerol diacrylate, glycerol triacrylate,
Trimethylolpropane triacrylate, ethylene glycol dimethacrylate, 1,3-propanediol dimethacrylate, 1,2,4-butanetriol trimethacrylate, 1,4-cyclohexanediol diacrylate, 1,4-
Benzenediol dimethacrylate, 1,2-benzenedimethanol diacrylate, pentaerythritol triacrylate, pentaerythritol tetramethacrylate, 1,3-propanediol diacrylate, 1,3-pentanediol dimethacrylate, p-α,α-dimethyl Benzyl phenyl acrylate, tertiary butyl acrylate, N,N-diethylaminoethyl acrylate, diethylaminoethyl methacrylate,
1,4-butanediol diacrylate, hexamethylene glycol diacrylate, decamethylene glycol diacrylate, 2,2-dimethylolpropane diacrylate, tripropylene glycol diacrylate, 2,2-di(p-hydroxyphenyl)propane , 2,2-di(di-hydroxyphenyl)propane dimethacrylate,
Polyoxyethyl-2,2-di(p-hydroxyphenyl)propane triacrylate (molecular weight
462), 1,4-butanediol dimethacrylate, hexamethylene glycol dimethacrylate, 2,2,4-trimethyl-1,3-pentanediol dimethacrylate, 1-phenylethylene-1,2-dimethacrylate, trimethylol Propane trimethacrylate, triethylene glycol diacrylate, ethylene glycol acrylate phthalate, polyoxyethyltrimethylolpropane triacrylate, aromatic polyhydroxy compounds such as bisphenols, novolaks and e.g. U.S. Pat. No. 3,661,576, incorporated herein by reference. Diacrylate and methacrylate esters of diepoxy polyethers derived from similar compounds described in the book, molecular weight
200-500 polyethylene glycol bisacrylates and methacrylates. Other suitable groups of ethylenically unsaturated compounds include U.S. Pat.
2927022, such as compounds having a plurality of addition-polymerizable ethylenic bonds, especially when present as terminal bonds, and especially those in which at least one and preferably most of such bonds are carbon-carbon dicarbonyl. Included are those conjugated with double-bonded carbons, including double bonds and carbon-heteroatom (eg nitrogen, oxygen and sulfur) double bonds.
Preference is given to such materials in which ethylenically unsaturated groups, especially vinylidene groups, are conjugated to ester or amide structures. Examples of such compounds include unsaturated amides, especially amides of α-methylenecarboxylic acid and especially α,ω-diamines and oxygen-interrupted ω-diamines, such as methylenebisacrylamide, methylenebismethacrylamide, ethylenebismethacrylamide. , 1,6-hexamethylenebisacrylamide, diethylenetriamine trismethacrylamide, bis(methacrylamidopropoxy)ethane, β-methacrylamidoethyl methacrylate, N-(β-hydroxyethyl)-
β-(methacrylamido)ethyl acrylate and N,N-bis(β-methacryloxyethyl)acrylamide, vinyl esters such as divinyl succinate, divinyl adipate, divinyl phthalate, divinyl terephthalate, divinylbenzene-1,3-disulfonate and divinyl Examples include butane-1,4-disulfonate, diallyl fumarate, and others. Other ethylenically unsaturated compounds that may be used include sterene and its derivatives, 1,4-diisopropenylbenzene, 1,3,5-triisopropenylbenzene, an adduct of itaconic anhydride and hydroxyethyl acrylate (1 :1),
Adducts of itaconic anhydride with liquid butadiene/acrylonitrile polymers having terminal amino groups, and adducts of itaconic anhydride with diacrylate and dimethacrylate esters of diepoxy polyethers as described in U.S. Pat. No. 3,661,576. , polybutadiene and butadiene/acrylonitrile copolymers containing terminal and pendant vinyl groups, and unsaturated aldehydes such as sorbaldehyde (2,4-hexadienal). When aqueous base developable systems are involved, ethylenically unsaturated compounds that are water soluble or contain carboxyl or other alkali-reactive groups are particularly suitable. Additionally, U.S. Patent No.
The polymerizable ethylenically unsaturated polymers described in 3043805 and 2929710 and similar materials can be used alone or in admixture with other materials. Also useful are acrylic and methacrylic esters of adducts of ethylene oxide and polyhydric hydroxy compounds, such as those described in US Pat. No. 3,380,831. Optical crosslinking polymers disclosed in US Pat. Nos. 3,418,295 and 3,448,089 can also be used. All of these patent specifications are incorporated herein by reference. The amount of unsaturated compound added should range from about 2 to about 40% by weight, based on the total weight of the composition. Specific amounts for optimal results will vary depending on the particular polymer used. Preferably the amount of unsaturated compounds ranges from about 5% to about 25%. Preferably, the ethylenically unsaturated compound has a boiling point of about 100° C. or higher at normal pressure. The most preferred ethylenically unsaturated compounds are triethylene glycol diacrylate, triethylene glycol dimethacrylate, hexamethylene glycol dimethacrylate and hexamethylene glycol diacrylate. The photosensitive compositions of the invention do not substantially scatter actinic radiation when in the form of thin layers as described above. The butadiene copolymer and polymer components should be compatible with the ethylenically unsaturated compound in the proportions used to ensure a substantially transparent mixture, i.e., a non-radiative scattering mixture;
and preferably should be soluble therein. "Compatible" means that the two or more components can remain dispersed with each other without scattering significant amounts of actinic radiation. Compatibility is often limited by the relative proportions of the components, and incompatibility is evidenced by the formation of haze in the photosensitive composition. In the production of printed reliefs, some slight haze before or during exposure can be tolerated. However, if fine detail is desired, haze should be completely removed. The amount of ethylenically unsaturated compound or any other component used is therefore limited to a concentration that does not cause undesirable light scattering or clouding. Other essential components of the photosensitive composition of the invention
(c) is an organic radiation-sensitive free radical generating system.
Practically any organic radiation-sensitive free radical-generating system that initiates and does not excessively terminate the polymerization of unsaturated compounds can be used in the photosensitive compositions of the present invention. The expression “organic” is
Used herein to refer to compounds containing carbon and one or more of oxygen, hydrogen, nitrogen, sulfur and halogens, but no metals. Since process transparencies transfer heat generated from conventional sources of active radiation and photosensitive compositions are typically prepared under conditions that provide elevated temperatures, the preferred free radical-generating compounds are below 85°C. and more preferably
It is thermally inactive below 185°C. They should be dispersible in the composition to the extent necessary to initiate the desired polymerization or cross-linking under the influence of the amount of radiation absorbed in relatively short exposures. These initiators are useful in amounts of from about 0.001 to about 10% by weight, and preferably from about 0.1 to about 5%, based on the total weight of the solvent-free photosensitive composition. This free radical generating system absorbs radiation in the range of about 2000 to about 8000 Å, which ranges from about 2500 to about
It has at least one component having an active radiation absorption band with a molecular extinction coefficient of at least about 50 in the range of 8000 Å and preferably in the range of about 2500-5000 Å. The expression "active radiation absorption band" refers to a radiation band active in generating the free radicals necessary to initiate polymerization or cross-linking of unsaturated materials. A free radical generating system may include one or more components that directly provide free radicals when activated by radiation. It may also include compounds, one of which generates free radicals after being activated by a radiation-activated sensitizer. A number of such free radical-generating compounds can be used in the practice of this invention, and include aromatic ketones such as benzophenone, Michler's ketone [4,4'-bis(dimethylamino)benzophenone], 4,4-bis(diethylaminobenzophenone, 4-acryloxy-4'-dimethylaminobezophenone, 4-
Acryloxy-4'-diethylaminobezophenone, 4-methoxy-4'-dimethylaminobenzophenone, 2-phenyl-2,2-dimethoxyacetophenone, 2-ethylanthraquinone, phenanthraquinone, 2-ethylaminobenzophenone, tertiary butylatraquinone,
1,2-benzathraquinone, 2,3-benzathraquinone, 2,3-dichloronaphthoquinone,
Benzyl dimethyl acetal and other aromatic ketones, benzoin, benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether and benzoin phenyl ether, methylbenzoin, ethylbenzoin and other benzoins, and 2,4,5- Triarylimidazole dimers such as 2-(o-chlorophenyl)-
4,5-diphenylimidazolyl dimer, 2-
(o-chlorophenyl)-4,5-di(m-methoxyphenyl)imidazolyl dimer, (2-(o
-fluorophenyl)-4,5-diphenylimidazolyl dimer, 2-(o-methoxyphenyl)
-4,5-diphenylimidazolyl dimer, 2-
(p-methoxyphenyl)-4,5-diphenylimidazolyl dimer, 2,4-di(p-methoxyphenyl)-5-phenylimidazolyl dimer,
2-(2,4-dimethoxyphenyl)-4,5-
Diphenylimidazolyl dimer, 2-(p-methylmercaptophenyl)-4,5-diphenylimidazolyl dimer, U.S. Patent Nos. 3479185 and 3784557, British Patent No. 997396 and
Other examples include those described in each specification of No. 1047569. These patents are incorporated herein by reference. The imidazolyl dimer is a free radical-generating electron donor such as 2-mercaptobenzoxazole,
Leuco crystal violet or avian (4-
Can be used with diethylamino-2-methylphenyl)methane. Sensitizers such as Michler's ketones can be added. Various energy transfer dyes such as Rose Bengal and Eosin Y may also be used. Other examples of suitable initiators are disclosed in US Pat. No. 2,760,863, which is incorporated herein by reference. The photosensitive composition may also contain a thermal addition polymerization inhibitor in small amounts, for example from 0.001 to 2.0%, based on the total weight of the solvent-free photosensitive composition. Suitable inhibitors include hydroquinone and alkyl and aryl substituted hydroquinones, 2,6-ditertiary butyl 4
-Methylphenol, p-methoxyphenol,
Tertiary butylpyrocatechol, pyrogallol, β
-naphthol, 2,6-ditert-butyl-p-cresol, phenothiazine, pyridine, nitrobenzene, dinitrobenzene and the nitrosodimer inhibitor system described in U.S. Pat. No. 4,168,982, incorporated herein by reference. can be given. Other useful inhibitors include p-torquinone, chloranil, and thiazine dyes such as thionine blue G (CI 52025), methylene blue B (CI 52015).
and toluidine blue (CI 52040). Such compositions can be photopolymerized or photocrosslinked without removing the inhibitor. A preferred inhibitor is 2,6-di-tert-butyl-
4-methylphenol and p-methoxyphenol. The oxygen and ozone resistance of the photosensitive compositions of the present invention and printed reliefs made therefrom is achieved by the inclusion in the photosensitive compositions of appropriate amounts of compatible, well-known antioxidants and/or antiozonants. It can be improved by Antioxidants useful in this invention include alkylated phenols such as 2,6-ditertiary-butyl-4-methylphenol, alkylated bisphenols such as 2,2-methylene-bis-(4-methyl-6-methylphenol), tertiary butylphenol), 1,3,5-trimethyl-2,4,
6-tris(3,5-ditert-butyl-4-hydroxybenzyl)benzene, 2-(4-hydroxy-3,5-ditert-butylanilino)-4,6
-bis(n-octylthio)-1,3,5-triazine, polymerized trimethyldihydroquinone and dilaurylthiopropionate. Ozone separation inhibitors useful in the present invention include microcrystalline waxes, paraffin waxes, dibutylthiourea, 1,1,3,3-tetramethyl-2-
Thiourea, "Antiozonant" AFD (product of Nafton), norbornene such as di-5-norbornene-2-methyl adipate, di-5-norbornene-2-methyl terephthalate, "Ozone Protector" 80 (product of Reichhld Chem.) ), N-phenyl-2-naphthylamine, unsaturated vegetable oils such as rapeseed oil, linseed oil, safflower oil, polymers and resins such as ethylene/vinyl acetate copolymer resins, chlorinated polyethylene, chlorosulfonated polyethylene, chlorinated ethylene /methacrylic acid copolymer, polyurethane, polypentadiene, polybutadiene, furfural derivative resin, ethylene/propylene/diene rubber, diethylene glycol ester of rosin, and α-methylstyrene/vinyltoluene copolymer. The ozone resistance of the printed relief produced can also be improved by annealing it at high temperatures before use. Optionally, the photosensitive composition includes an immiscible polymeric or non-polymeric organic or inorganic filler that is essentially transparent at the wavelength used for exposing the photosensitizer and does not scatter actinic radiation; Reinforcing agents such as polystyrene, organophilic silica, bentonite, silica, powdered glass, colloidal carbon and various types of dyes and pigments may also be included. Such materials are used in varying amounts depending on the desired properties of the elastomeric composition. Fillers are useful in improving the strength of the elastomer layer, reducing tack, and even as colorants. The photosensitive layer preferably contains a compatible plasticizer to lower the glass transition temperature of the binder and facilitate selective development. The plasticizer can be any common plasticizer that is compatible with the polymeric binder. Among the common plasticizers are dialkyl phthalates, alkyl phosphates, polyethylene glycols, polyethylene glycol esters and polyethylene glycol ethers.
Other useful plasticizers include oleic acid, lauric acid, and others. Polyesters such as polyethylene sebacate and others are preferred plasticizers. Plasticizers are generally present in an amount of 1 to 15% by weight, based on the total solids weight of the photosensitive composition. The photosensitive compositions of the present invention can be prepared by mixing the components (a) the high molecular weight butadiene/acrylonitrile copolymer, (b) the compatible ethylenically unsaturated compound, and (c) the free radical generating system in any suitable manner. It can be manufactured by For example, flowable compositions may contain these and other desired additives in any order and optionally solvents such as chlorinated hydrocarbons such as chloroform, chlorobenzene, trichloroethylene and chlorotoluene, ketones such as methyl ethyl ketone, diethyl ketone and methyl isobutyl ketone, aromatic It can be prepared by mixing with the aid of group hydrocarbons such as benzene, toluene and xylene, and tetrahydrofuran. The solvent includes acetone as a diluent,
It may contain low molecular weight alcohols such as methyl, ethyl and propyl alcohol and esters such as methyl acetate, ethyl acetate and butyl acetate. The solvent can later be removed by heating the mixture or extruded layer. Conventional milling, mixing and solution techniques can be used in making these compositions. Specific techniques will vary due to differences in the properties of each component. The homogeneous, substantially non-radiative scattering composition is formed into a sheet in any desired manner. For example, solvent casting, hot pressing, calendering or extrusion are suitable methods for producing layers of the desired thickness. The photosensitive elements of the present invention are prepared by forming the photosensitive composition into a layer or self-supporting sheet on a suitable forming wheel, belt or platen by solvent casting or extrusion, calendering or pressing at elevated temperatures. It can be manufactured by This layer or sheet can be laminated onto the flexible support surface and adhered by the adhesive blend described below. If a solution is used, the coating is created on an adhesive-bearing support. The thickness of the photosensitive layer is a direct function of the thickness desired in the relief image, and this depends on the object being replicated and the end use of the relief. For example, thick soft relief is useful for flexographic printing and thin hard relief is useful for planographic printing. Generally, the thickness of this photopolymerizable layer is about 0.250 inch or less. For example, it is about 0.0005 to about 0.250 inch (0.00127 to
0.635 cm), and layers in this thickness range are used for the majority of printing plates. Between the photosensitive layer and the flexible support is a layer of an adhesive blend, which includes at least two polymers from the following four polymer groups: . (1) Polyester resin, which is a condensation polymer of ethylene glycol, terephthalic acid, isophthalic acid and azelaic acid in a molar ratio of about 6:2:1:3, with ^- _M n 19000 and ^- _M n 37000. (2) Polyether polyurethane resin, which was prepared at 15% solids in methyl ethyl ketone and at 12 rpm using a #3 Bruckfield spindle.
It is a crystalline thermoplastic resin with a Bruckfield viscosity of 100-1200 centipoise and an adhesive activation temperature ranging from 54-63°C. This polyether polyurethane has a yield elongation of 15%,
615% elongation at break, 600psi (42.18Kg/cm ² )
It has a modulus at 400% elongation and a decrystallization temperature of about 49°C. (3) Polyamide resin, which has a translucent light amber color, a ball-and-ring softening point of 132-145°C, a melt viscosity of 40-60 poise at 210°C, an ignition point of over 299°C, and a water resistance of 1 day. Absorption% 0.7, 7-day water absorption% 1.6, tensile yield strength of 460 psi (32.34 Kg/cm ² ), tensile breaking strength of 450 psi (31.64 Kg/cm ² ) and elongation degree of 560% (tensile Yield strength, tensile strength at break and elongation are measured at 24°C by ASTM method D-1708). (4) Polyamide resin, which has a translucent light amber color, a ball-and-ring softening point of 150-160°C, a viscosity of 28-38 poise at 210°C,
The 1st day water absorption% is 1.5, the 7th day water absorption% is 2.8,
and

(Tensile yield strength, tensile breaking strength and degree of elongation are determined by ASTM method D-1708 at the indicated temperatures). The number average molecular weight (n) of the resin can be determined by gel permeation chromatography using known standards such as polybutadiene, as is well known to those skilled in the art. The weight average molecular weight (w) of a resin can be determined using light scattering techniques using known standards such as polystyrene, polymethacrylic acid, polymethyl methacrylate, etc., as is known to those skilled in the art. Certain polymers can be present in the adhesive blend in the following ranges, based on the total resin weight in the adhesive composition: (1) 0-78% by weight, (2) 0-78% by weight,
(3) 0-94% by weight and (4) 0-97% by weight. 4 types, 3
Preferred adhesive blends containing seeds and two resin components are described below, where %
is on a weight basis based on total resin content. Preferred ranges for four-component adhesive blends are as follows. (1) 25-31%, preferably 25% (2) 25-31%, preferably 25% (3) 25-19%, preferably 25% (4) 25-19%, preferably 25% 2 pieces The preferred ranges for three-component adhesive blends A and B are as follows: A (1) 1-78%, preferably 1-65% (2) 1-78%, preferably 1-65% (3) 1-94%, preferably 1-90% B (1) 1-63 %, preferably 1-45% (3) 1-93%, preferably 1-85% (4) 1-97%, preferably 1-90% Preferred ranges for the five two-component adhesive blends C-G is as follows. (1) 7-77%, preferably 15-50%, most preferably 30%; and (3) 93-23%, preferably 85-50%, most preferably 70% (this adhesive blend is particularly preferable). D (1) 3-60%, more preferably 5-30%, and (4) 97-40%, more preferably 95-70%. E (1) 23-77%, more preferably 35-45%, and (2) 77-23%, more preferably 65-55%. F (2) 10-16%, preferably 25-30% and (4) 90-40%, preferably 75-70%. G (2) 7-72%, preferably 15-50%, and (3) 93-28%, preferably 85-50%. The adhesive blend of the present invention has at least 3 lbs.
It provides adhesion values for the photosensitive layer to the support in the adhesion range of 8 pounds/inch (53.57 Kg/m) and generally much greater, such as 8 pounds/inch (142.86 Kg/m) or more. These adhesion values are sufficient if the elements of the invention are used as printing plates, especially flexographic printing plates. The adhesive blend preferably contains additives such as antiblocking agents, colorants such as dyes, and the like. Useful antiblocking agents preferably include polyolefin particles or beads, but also other hard particles or beads, such as silicon dioxide and the like. Dioctyl sodium sulfosuccinate surfactant can be used. Preferred polyolefin materials are described in the Examples. The bead size of the antiblocking agent can be greater than the thickness of the adhesive layer so that some of the beads protrude from the layer of adhesive blend. Such structures appear to have little or no effect on the extent of adhesion. Many types of colorants or dyes are also useful in the adhesive layer. A preferred dye is Dupont Milling Blue BL (CI Acid Blue 59). Other useful dyes include methylene violet (CI Basic Violet 5), "Laxol" Fast Blue
MBSN (CI Solvent Blue 38), "Pontasil"
Wool Blue BL (CI Acid Blue 59 or
CI50315), "Pontasil" Wool Blue GL (CI Assisted Blue 102 or CI50320), Victoria Pure Blue BO (CI Basic Blue 7 or
CI42595), Rhodamine 3GO (CI Basic Cred 4), Rhodamine 6GDN (CI Basic Cred 1 or CI54/60), Fuchsin Dye (CI42510), Chalcoside Green S (CI44090) and Anthraquinone Blue 2GA (CI Acid Blue 58). The adhesive solution is generally prepared by adding the following components to the solvent in the following order with continuous stirring: polymer, polyolefin antiblocking agent, and colorant. Useful solvents include, for example, methylene chloride/ethyl acetate, methylene chloride/
n-butyl acetate, methylene chloride/cyclohexanone, methylene chloride/methanol/
Cellosolve and other mixtures and preferably a 90/10 methylene chloride/Cellosolve mixture. Additional solvent can be added to make up for any lost weight. The choice of solvent ensures that the coating does not form blisters.
and is governed by the desire to provide the fastest practical drying rates without leaving behind small amounts of solvent. The solvent should also have a solubilizing effect on the dyes that may be present. This adhesive solution is then applied to the flexible support by known methods. For example, this can be achieved by coating by the use of a doctor blade or in a commercially available continuous web coater dryer at a concentration of about 80-500 mg/dm2, preferably about 260-300 mg/ ^dm2 .
Producing dry coating weights in the range of mg/dm ² . The most preferred coating weight for this adhesive layer is about 260 mg/dm ² . Generally, the adhesive layer has a dry thickness of 0.0008 to 0.001 inch (0.020 to 0.025 mm). For continuous coating, web speeds may range from 15 to 150 ft/min (4.57
~45.72 m/min). The drying temperature ranges from 60 to 130°C, preferably from 80 to 90°C. A preferred flexible support is flame treated polyethylene terephthalate 0.001 to 0.007 inches (0.025 to 0.178 mm) thick, preferably 0.005 inches (0.13 mm) thick. No. 3,145,242, US Pat. No. 3,360,029, and US Pat. No. 3,360,029, incorporated herein by reference.
No. 3,391,912 describes methods and apparatus useful for flame treating polymeric films. Fuel equivalence ratio of combustible gas mixture φ
is 1.4, which is equal to 5 (propane flow rate)/[(oxygen flow rate) + (0.21 air flow rate)]. All flow rates are standard cubic feet or standard cubic meters per minute. Web speed is 175 linear feet/
minute (53.34 m/min). The dried adhesive coated support can be adhered immediately to the photosensitive layer or it can be saved for subsequent adhesion. The adhesive-coated support is heated in a press ^at e.g.
The photosensitive layer can be laminated to the photosensitive layer at a pressure of 100° C. and then cooled to below 60° C. in a press. Preferably, the photosensitive element is as described in Example 8 below.
Manufactured by calendering as described in . The photosensitive layer, produced by extrusion through a die, has a layer on the side adjacent to the adhesive layer and on the side remote from it, which subsequently acts as a protective cover sheet.
Preferably, a 0.005 inch (0.13 mm) thick polyethylene terephthalate film is present.
Other films such as polystyrene, polyethylene, polypropylene or other release materials can be used. Preferably, between the photosensitive layer and the film cover sheet there is present a thin, rigid, flexible, solvent-soluble layer, such as a flexible polymeric film or layer, such as polyamide or ethylene/vinyl acetate copolymer. This flexible polymeric film remains on the photosensitive layer after removal of the film cover sheet. The flexible polymeric film protects the image-containing negative or overlying transparency for reuse, or improves contact or registration with the light-sensitive surface. Prior to imagewise exposure using the light source described below, the element is exposed through the support to polymerize a predetermined thickness of the photosensitive layer adjacent the adhesive support. This polymerized portion of the photosensitive layer is called the floor. Floor thickness varies depending on exposure time, light source, etc. Exposure is generally 1 to 30 minutes. The printed relief can, for example, be a process transparency, i.e. a portion of actinic radiation substantially transparent and of substantially uniform optical density, according to the invention;
Activating selected portions of the photosensitive layer through an image-bearing transparency or stencil having portions opaque to actinic radiation and of substantially uniform optical density until substantial addition polymerization or optical cross-linking occurs. It can be produced by exposure to line radiation. During addition polymerization or crosslink formation, the butadiene polymer/ethylenically unsaturated compound composition is converted to an insoluble state in the radiation-exposed parts of the layer, with no significant polymerization or crosslinking occurring in the unexposed parts of the layer. No binding occurs. The unexposed portions of the layer are removed with a solvent for high molecular weight butadiene polymer. Process transparencies can be made from any suitable material, including cellulose acetate film and oriented polyester film. Actinic radiation from any light source and of any type can be used in this photopolymerization process. This radiation may originate from a point source or it may be in the form of parallel rays or a diverging beam. By using a wide radiation source relatively close to the image-bearing transparency,
Radiation passing through the transparent portion of the transparency enters as a diverging beam and thus illuminates a continuous diverging portion of the photosensitive layer below the transparent portion of the transparency. This results in a ie trapezoidal polymer relief with the widest width at the bottom of the photosensitive layer.
The upper surface of the relief is the dimension of the transparent part. Insofar as free radical generating systems activatable by actinic radiation generally exhibit their maximum sensitivity in the ultraviolet region, the radiation source should provide an effective amount of radiation having this preferably wavelength range of about 2500 Å to 5000 Å. Suitable sources of such radiation other than solar radiation include carbon arcs, mercury vapor arcs, fluorescent lamps with ultraviolet radiation generating phosphors, argon glow lamps, electronic flash units and photographic flood lamps. Electron accelerators and electron beam sources through a suitable mask may also be used. Among these, mercury vapor lamps, especially the sunlamp or "black light" type and fluorescent sunlamps are the most suitable. The radiation exposure time depends on the intensity and spectral energy distribution of the radiation, its distance from the composition and the nature and amount of composition available.
It can vary from seconds to minutes. Typically about 1.5 to about 60 inches (3.8cm to 153cm) from the photosensitive composition
A mercury vapor arc or a solar lamp is used at a distance of . Exposure temperature is not particularly critical. However, it is generally preferred to operate at ambient or slightly higher temperatures, ie from about 20 DEG to about 35 DEG C. After exposure, it can be developed by washing with a suitable solvent. Although the solvent liquid has a good solvent or swelling effect on the butadiene polymer/ethylenically unsaturated compound composition, it does not result in insolubilized images or The support or adhesive layer should have little effect. Suitable organic solvents include 2-butanone, benzene, toluene, xylene, trichloroethane, trichloroethylene, methylchloroform,
Mention may be made of tetrachlorethylene and other solvent mixtures such as tetrachlorethylene/n-butanol. When the high molecular weight butadiene polymer component contains carboxyl groups, suitable solvents include aqueous bases to which a water-soluble organic solvent may be added. Specific suitable solvent mixtures include sodium hydroxide/isopropyl alcohol/water, sodium carbonate/water, sodium carbonate/2-butoxyethanol/water, sodium borate/2-butoxyethanol/water, sodium silicate/2-butoxyethanol. ／Glycerol／
water, sodium carbonate/2-(2-butoxyethoxy)ethanol/water, and 16% by volume of 2-
(2-Butoxyethoxy) Sodium hydroxide (0.5% by weight) in ethanol. This last one is preferred. The particular solvent combination chosen will depend on the carboxyl content of the photosensitive composition and the nature and amount of binder used. Other aqueous solvent combinations that may be used are described in U.S. Pat.
It is described in the specification of No. 3796602. These aqueous base/water-soluble organic solvent combinations may be preferred in some cases because of their low cost, nonflammability, and low toxicity. Solvent development may be carried out at about 25°C. However, best results are sometimes achieved when the solvent is warm, e.g. 30-60°C.
obtained in the case of . Development times may vary, but are preferably within the range of 5 to 25 minutes. In the development step where the relief is formed, the solvent may be applied in any convenient manner, for example by injection, impregnation, spraying or roller application. Only brushes are useful in removing non-polymerized or non-crosslinked portions of the composition. After liquid development, the plate is dried in heated air at room temperature, optionally in a forced hot air dryer or other suitable dryer, and allowed to dry at room temperature to about 125°C, preferably 60°C, for 1 hour. The dried plate is then detackified by treatment with an aqueous hypochlorite solution such as 900 parts water, 90 parts Clorox and 10 parts concentrated HCl and dried. 5-15 using the light source used for imagewise exposure
After a minute of exposure, the plate is ready for use. Printed reliefs produced from the light-sensitive flexographic elements of the invention can be used for all types of printing, but only those where a clear difference in height between the printed and non-printed parts is required. The present invention is most applicable to flexographic printing, and in particular to flexographic printing of the type where a resilient printing part is required, for example for printing on a deformable printing surface. These types include dry offset printing, where the ink is carried by the raised part of the relief, as in regular letterpress printing (which requires a greater height difference between printed and non-printed areas). and those in which the ink is carried by recesses in relief, as in intaglio printing, for example in lines and reverse halftones. This plate is also useful for multicolor printing. The resulting relief and printed images exhibit fidelity to the original both in fine detail and overall dimensions even when the element is imagewise exposed on a cylindrical support. This relief has high impact strength, is tough yet abrasion resistant and has wide ink compatibility. Thus, it has good compatibility with a wide range of inks, such as water-based inks, hydrocarbon inks and alcohol-based inks. The following examples serve to illustrate the invention, in which parts and percentages are by weight. The adhesion values in the examples are measured by the following peel test method. Sample 1 inch x 6 inches (2.54 x 15.24 cm)
Cut into size. After providing appropriate exposure through the support and imagewise exposure to actinic radiation (unless stated otherwise), one corner of the support is pinched loose from the photosensitive layer and removed by hand for approximately 1.5
Peel off a distance of 1 inch (3.81 cm). It may be necessary to use a pair of pliers to grip the stripped photosensitive layer during this operation. Insert the prepared sample into the jaw of the Instron Universal Testing Instrument Model TTC (manufactured by Instron Engineering). At that time, the photosensitive layer is placed on the upper layer,
The peeled support is then inserted into the lower jaw. The test is conducted at a crosshead separation speed of 10 inches/minute (25.4 cm/minute). Tensile load cell C
is used, for which the maximum allowable load is 50
lb (22.68Kg), the initial separation is 3/8 inch (0.95cm), and the initial peel angle is -
90° at the support and the final peel angle is 45-60°.
The stress for sample peeling is read from a recorder on the machine. Divide this by 1.0 inch (2.54 cm) (sample width) to obtain the appropriate unit. If the adhesive strength (adhesion) is greater than or equal to 8 pounds/inch (142.86 Kg/m), the photosensitive layer will break or break without peeling during testing. The polymers present in the adhesive blend are designated by the numerical symbols (1), (2), (3) or (4) as previously described. Example 1 An adhesive solution is prepared from the following ingredients. Component amount (parts) Polyamide resin (3) Lot No.OF5237 63.1 Polyester resin (1) 27.0 Polyolefin 9.8 Dupont Milling Blue BL dye 0.1 (CI Acid Blue 59) Polyamide resin (3) is "Macromelt" 6238 ( Henkel Adhesives Company Products) This is a translucent light amber color and is heated to 132-145 degrees Celsius.
Ring softening point, melt viscosity of 40-60 poise at 210℃,
Ignition point above 299℃, 1 day water absorption% of 0.7, 1.6
It has ^a 7 ^- day water absorption% of Strength and elongation are
(measured at 24°C by ASTM method D-1708). The above polyester resins are M n19000 and M
It is a reaction product of ethylene glycol, terephthalic acid, isophthalic acid and azelaic acid (molar ratio 6:2:1:3) with w37000. The polyolefin is "Vestofine" SF-616 (manufactured by Doula Commodities), which is snow white in color, has a molecular weight of about 1600, a density of about 0.96 at 20°C, and a density of 0.5 to 1.0 at 25°C. and a melting point of about 118-128℃, of which about 85% is 10μ or less and about 15% is
It has a particle size of 10-20μ. The above components are added in sequence to a methylene chloride/cellosolve (90/10) mixture to produce a solution of about 16% solids. Polyolefin beads do not dissolve. The mixture is continuously stirred during and after the addition of the ingredients to effect dissolution. Any weight loss during mixing is compensated by the addition of methylene chloride. This adhesive solution is applied to the flame treated surface of a 0.005 inch (0.13 mm) thick polyethylene terephthalate film support using a continuous web coater dryer to give a dry coating weight of about 260 mg/dm ² . Web speed is 45 feet/
min (13.72 m/min), and the drying temperature is 86 m/min.
℃ (205〓). The adhesive coated polyethylene terephthalate support is placed adhesive side up in a steel platen fitted with a die 0.080 inch (2.03 mm) thick, the thickness of the final printing plate. The adhesive coated support and platen were placed on a press and a 0.090 inch (approximately 2.29 mm) thick photopolymerizable composition supported by a 0.005 inch (0.13 mm) thick polyethylene terephthalate support. The extruded sheet of material is kept support side up and covered with a steel plate. Extruded sheets of photopolymerizable compositions are manufactured from the following ingredients. Blend these and extrude the blend through a die at 170°C. Ingredient amount (parts) Acrylonitrile (27) / Butadiene (70) /
High molecular weight copolymer of acrylic acid (3) (average Mooney viscosity 45.0, “Hiker” 1472×26) 81.59 Hexamethylene diacrylate 10.0 Polyethylene sebacate 5.0 Dibutyltin-3,S′-bis-isooctylmercaptoacetate 2.0 2 -Phenyl-2,2-dimethoxyacetophenone 1.25 2,6-ditertiary-butyl-4-methylphenol
0.10 1,4,4-trimethyl-2,3-diazabicyclo(3,2,2)-nonar-2-ene-2,3
- Dioxide 0.05 Dupont Milling Blue BL dye (CI Acid Blue 59, 0.01 10% dispersion in ethylene glycol) (dry) The above polyethylene sebacate is a low molecular weight polyester resin with the trade name "Paraplex" G-30. Available from Rohm and Haas. Increase temperature and apply pressure gradually.
This causes the photopolymerizable sheet to spread over the entire area of the platen surrounded by the die. After the sheets are evenly distributed, the temperature is increased to 160℃,
A pressure in the range of 20,000-30,000 psi (1406-2109 Kg/cm ² ) is then applied and held for 3 minutes. The assembly is cooled in the press to below 60°C by flowing water through the press platen. The formed laminated element is removed from the press and placed, support side up, under a row of black fluorescent lamps, such as Sylvania BL lamps. The element is exposed through the support for 4 minutes to polymerize the intended thickness of the photopolymerizable layer adjacent to the adhered support. The overlapping portion of the elements is called the floor. Next, add this element to Sylvania (BL-
"Cyrel" 3040 with VHO fluorescent light
Place it in the exposure unit (DuPont product). The photopolymerizable surface is covered with an image-bearing transparency (negative) and the element is exposed under vacuum for 15 minutes. The duration of exposure is a function of the photopolymer sheet thickness, polymeric floor thickness and type of image-bearing transparency used. After exposure, the transparency is removed and the exposed element is placed in a rotating drum brush type "Shillel" 3040 processor. The unpolymerized portion of the element is removed in the processor by washing with 0.5% by weight sodium hydroxide in 16% by volume 2-(2-butoxyethoxy)ethanol in water for 15 minutes. 0.035
An inch (0.83mm) relief image is obtained. The developed element (printing plate) is placed in a forced hot air dryer or other suitable dryer and dried for 1 hour at 60°C. The dry plate was then mixed with an aqueous hypochlorite solution (900 parts water, 90 parts Clorox and 10 parts concentrated water).
Detack for 1-3 minutes in HCl) and dry again. The dried plate is post-exposed for 10 minutes in air using the same exposure light source used for the imagewise exposure. This plate is 50-60
Shore A2 hardness in the range (ASTM test method D2240)
have. The plate can now be mounted onto a flexographic press cylinder using commercially available double-sided tape and printed using standard flexographic inks. Print quality is comparable or better than that produced using similarly printed rubber plates. The adhesion of the photopolymer layer to the support is 8
It is greater than pounds per inch (142.86Kg/m). Example 2 An adhesive solution is prepared as described in Example 1. This solution is applied to a flat surface on a 0.005 inch (0.127 mm) thick polyimide flexible film support, Kapton Polyimide Film (manufactured by DuPont). A measured amount of adhesive solution is poured onto the surface of the support and spread with a 0.006 inch (0.15 mm) doctor knife. Allow this adhesive coating to air dry. 0.001 inch (0.025
The extruded photosensitive layer with a thickness of up to 1 mm) is pressed onto the adhesive-coated support by the procedure described in Example 1. The final pressing temperature is 160℃,
And the pressure is about 25000psi (1757.5Kg/cm ² ).
After the pressed plate has cooled as described in Example 1, it is removed from the press. The plate is cut into 1.0 inch by 60 inch (2.54 cm by 15.28 cm) wide strips and exposed entirely in the exposure apparatus of Example 1 for 3 minutes on the support side and 30 minutes on the light sensitive side. Attempts to peel off the photosensitive layer were unsuccessful. The photosensitive layer was cut in the adhesive state.
This is 8.0 lb/in (142.86 Kg/m)
The above adhesive values are shown. Example 3 Example 2 is repeated except that the adhesive solution is prepared from the following ingredients. Component Amount (g) Polyester resin described in Example 1 10772.0 Polyether polyurethane resin 16204.0 Polyolefin described in Example 1 2996.0 Dupont Milling Blue BL dye (CI Acid Blue 59) 28.0 This polyether polyurethane resin was manufactured by K.G. Quinn Company. 's product "Q-Thane
”P250-1 in methyl ethyl ketone
Bruckfield viscosity of 100 to 1200 centipoise at 12 rpm using 15% solids and #3 Bruckfield spindle, and adhesive activation temperature ranging from 54 to 63 °C, and crystalline state breakdown temperature of approximately 49 °C It is a crystalline thermoplastic resin with As in Example 2, the photosensitive layer was adhesively destroyed and
m) or higher. Examples 4-6 Several adhesive solutions are prepared as described in Example 1. This solution is applied to the flat surface of the flexible support described in Table 1 below. A measured amount of adhesive solution is poured onto the surface of the support and spread with a No. 65 wire-wound stainless steel rod. Allow the adhesive coating to air dry. The extruded photosensitive layer described in Example 2 is pressed onto an adhesive-coated support in the manner described in Example 2. After the pressed plate has cooled as described in Example 1, it is removed from the press. The plate is cut as described in Example 2 and exposed overall for 25 minutes in the exposure apparatus described in Example 1. The measured adhesion values are listed in Table 1.

Table: Example 7 An adhesive solution is prepared as described in Example 1 from the following ingredients: Component Amount : Mixture of 2 to 4 Resin Types and Resin (Solid content of 90% by weight or more based on total weight in adhesive solution), refer to Table 2 for the antiblocking agent described in Example 1 9.2 ^* Dye described in Example 1 0.1 ^* (Note) *Based on the total weight of solids in the adhesive solution. Samples 7, 25-28 and 40-70 are coated as described in Example 1 at the approximate coating weights indicated. Samples 1-6, 8-24, 29-39 and 71-87 are coated as described in Example 2 at the approximate coating weights listed. The support coated with the adhesive solution was flame treated polyethylene terephthalate for samples 1-40, 42-49, 52-67, 69 and 74-87 and for samples 41, 68, 70 and 71-73. and for Samples 50 and 51, electron discharge treated polyethylene terephthalate (1.0-6.0 joules/inch (0.39-2.36 joules/cm)). The photosensitive layer described in Example 1 is laminated by the procedure described in Example 1 onto the adhesive coated support described in Table 2. After removal from the press, the laminated element is processed as described below. The back exposure source exposure unit, processor and dryer are described in Example 1. [A] 4 minutes of exposure through the support, 15 minutes of imagewise exposure
minutes, solvent washing as described in Example 1 for 10 minutes, drying for 60 minutes. Post-processing was as described in Example 1, with post-exposure in air 10
Minutes. Applicable to samples 1 to 7. [B] 4 minutes of exposure through the support, 15 minutes of imagewise exposure
minutes, no solvent wash, no drying, no post-treatment as described in Example 1, 15 minutes post-exposure in air. Applicable to samples 8 to 13. [C] 4 minutes of exposure through the support, 30 minutes of imagewise exposure
minutes, solvent wash, drying, post-processing, and post-exposure. Applicable to samples 14-34. [D] No treatment for samples 35-39. sample 44
~77 and samples 82-85 are tested after removing the laminated elements from the press. [E] Same process as [C] above. However, exposure through the support is 3 minutes. Applicable to samples 40-43. [F] Same process as [C] above. However, imagewise exposure is 25 minutes. Applicable to samples 78-81. [G] 4 minutes of exposure through the support, 15 minutes of imagewise exposure
minutes, solvent washing, drying, and post-processing. Post-exposure 10 minutes in air. Applicable to samples 86-87.

【table】

【table】

【table】

[Table] In the above sample 10, "Eftofine" was used as an anti-blocking agent. This thing has a melting point
235~245〓(113~118℃), Freezing point (ASTM0938) 206~210〓(97~99℃), 77〓
Penetration value at (25℃) (ASTM D1321) 0.9~
1.4 (mm/10), average particle size 2μ, maximum particle size 10μ for 99% of the weight, synthetic hydrocarbon wax. Example 8 A flexographic printing plate was prepared with a photopolymerizable composition and adhesive coated support as described in Example 1, and a 0.005 inch (0.127 mm) polyamide resin layer having a dry thickness of 0.00017 inch (0.004 mm). Manufactured using thick polyethylene terephthalate cover sheet. This cover sheet with a polyamide layer is produced by coating a polyethylene terephthalate film using an extrusion die coater with the following solution: Ingredients (%) Methylene chloride 81.0 Methanol 2.0 N-Methylpyrrolidone 10.0 Polyamide resin 7.0 This polyamide resin "Macromelt" 6900 is essentially colorless, with a ball-and-ring softening point of 266-302〓, and a ball-and-ring softening point of 347〓. Melting index of 5-15g/10min, ignition point of 570〓, daily water absorption% of 0.2,
7-day absorption% of 0.5, tensile yield point of 1200psi,
It has a tensile failure point of 3500psi and an elongation of 540%. Tensile yield point, tensile break point and degree of elongation are determined by ASTM method D-1708 at 24°C. The components of the photopolymerizable composition are fed into a twin screw extruder, the binder component is added through the solids inlet, and the remaining blended components are introduced through the liquid inlet. The extruder functions to melt, mix, devolatilize, and evaporate the photopolymerizable composition at 164-166° C. before sending it to the extrusion die. The extruded photopolymerizable composition enters a rotating bank in a two roll calender and is calendered between the adhesive side of the coated support and the polyamide layer side of the cover sheet. The calender nip can be adjusted to produce photopolymerizable layers over a wide range of thicknesses, for example 0.112 inches (~285 mm). A photopolymerizable element with a photopolymerizable layer thickness of 0.112 inches (~2.85 mm) is cooled by blowing air and passed under a bank of black-light fluorescent lamps, e.g., Sylvania BL lamps, placed laterally in a travel path. The element is sequentially exposed to light through the support to polymerize a predetermined thickness of the photopolymerizable layer on the support. Cut the element to a convenient length, such as 40 inches (101.60 cm). The photosensitive element is placed in an exposure unit as described below and subjected to general exposure through the support in air for a predetermined length of time (e.g. polymerization of a 0.080 inch (2.03 mm) portion of the layer). The required 0.112 inch (~2.85 mm) thick photopolymerizable layer is exposed for about 3 minutes depending on the light source intensity]. The polyethylene terephthalate film on the surface of the polyamide layer is then peeled off. The polyamide layer remains adhesive to the photopolymerizable layer. The hard, flexible, smooth polyamide surface is covered with an image-bearing transparency, and the flat polymerizable layer is coated with Sylvania BL under vacuum for 5 minutes.
- Imagewise exposure in a Schiller 3040 exposure unit (DuPont) with VHO fluorescent lamp. After exposure, the transparency is removed and the exposed element is placed in a Schiller 3040 processor in the form of a rotating drum brush. The unpolymerized portion of the element is removed in the processor by washing with 0.5% by weight NaOH in 16% by volume 2-(2-butoxyethoxy)ethanol in water. Place the developer element (printing plate) in a forced hot air dryer or other suitable dryer. and dry at 60 °C until the plate achieves its initial thickness. The dry plate is then soaked in an aqueous acidic hypochlorite solution (900 parts water, 90 parts Clorox, 10 parts concentrated water) for 1-3 minutes.
Remove stickiness in HCl). The plate can be left wet or allowed to dry again. The plate is then post-exposed for 10 minutes using the same exposure source used for the imagewise exposure above. The printing plate has a shore A2 hardness (ASTM test method D2240) in the range 56-60. This printing plate can be used for printing as described in Example 1 with comparable results. The adhesion value of this photopolymer to the substrate is greater than 8 pounds per inch (142.86 kg/m).

Claims (1)

[Scope of Claims] 1 (A) a flexible support and (B) the following components based on the weight of the total composition: (a) a number average molecular weight of 20,000 to 75,000 and a number average molecular weight of 10 to 50;
55-90% by weight of a high molecular weight butadiene/acrylonitrile copolymer having an acrylonitrile content of % and a carboxyl content of 0-15% by weight; (b) free radical initiated chain extension containing at least one terminal ethylenic group; 2 to 40% by weight of a non-gaseous ethylenically unsaturated compound capable of forming a high molecular weight polymer by addition polymerization and compatible with the polymer of (a); and (c) active radiation for initiating polymerization of the unsaturated compound. 0.001 to 10% by weight of an organic radiation-sensitive free radical-generating system activatable by radiation; and between layer (A) and layer (B); (1) a condensation polymer of ethylene glycol, terephthalic acid, isophthalic acid and azelaic acid in a molar ratio of about 6:2:1:3 and having a number average molecular weight of about 19,000 and a weight average molecular weight of about 37,000; (2) 5% solids by weight in methyl ethyl ketone and a Bruckfield spindle #3 at 12 rpm;
Crystals having a Bruckfield viscosity of 100 to 1200 and having an adhesive activation temperature in the range of 54 to 63°C and in an amount of 0 to 78% by weight based on the total resin weight of the adhesive composition. (3) Ball-and-ring softening point of 132-145°C, viscosity of 40-60 poise at 210°C, ASTM D
-1708 % elongation of 130 measured at -18°C, 560 measured at 24°C and 100 measured at 60°C;
4000psi measured at -18°C with ASTM D-1708,
Measured at 24℃ and 450psi and measured at 60℃
(4) a thermoplastic dimer acid polyamide resin having a tensile rupture of 170 psi and in an amount of 0 to 94% by weight based on the total resin weight of the adhesive composition; Andring softening point, viscosity 28-38 poise at 210°C, ASTM D
-1708 % elongation of 350 measured at -18°C, 250 measured at 24°C and 40 measured at 60°C;
2200 psi measured at -18°C with ASTM D-1708,
Measured at 24℃ and 360psi and measured at 60℃
At least two members taken from the group consisting of polyamides that are thermoplastic dimer acid polyamide resins having a tensile breaking strength of 50 psi and in an amount of 0 to 97% by weight based on the total weight of resin of the adhesive composition. A photosensitive flexographic element comprising a layer of an adhesive composition comprising a blend of polymers. 2. The adhesive blend composition contains 25-31% by weight polyester resin (1), 25-31% by weight polyether polyurethane resin (2), 25-19% by weight based on the total weight of resin in the adhesive composition. polyamide resin (3) and
Flexographic element according to claim 1, containing from 25 to 19% by weight of polyamide resin (4). 3. The adhesive composition contains 1 to 78% by weight of polyester resin (1) based on the total weight of resin in the adhesive composition.
~78% by weight polyether polyurethane resin (2),
and 1 to 94% by weight of polyamide resin (3). 4 The adhesive composition contains 1 to 78% by weight of polyester resin (1) based on the total weight of resin in the adhesive composition, 1
Flexographic element according to claim 1, containing from 1 to 93% by weight of polyamide resin (3) and from 1 to 97% by weight of polyamide resin (4). 5. The above-mentioned patent claim, wherein the adhesive composition contains 20 to 50% by weight of polyester resin (1) and 80 to 50% by weight of polyamide resin (3), based on the total weight of resins in the adhesive composition. The flexographic element according to item 1. 6. The above-mentioned patent claim, wherein the adhesive composition contains 3 to 70% by weight of polyester resin (1) and 97 to 30% by weight of polyamide resin (4), based on the total weight of resins in the adhesive composition. The flexographic element according to item 1. 7. The adhesive blend composition contains 25-75% by weight polyester resin (1) and 75-25% by weight polyether polyurethane resin (2) based on the total weight of resins in the adhesive composition. A flexographic element according to claim 1. 8. The flexographic element according to claim 1, wherein the adhesive composition contains a colorant. 9. The flexographic element according to claim 1, wherein the adhesive composition contains an antiblocking agent. 10. The flexographic element of claim 8, wherein the antiblocking agent is particles of tough, rigid polyolefin that melts in the range of about 120-128°C and has a molecular weight of about 1600. 11. The flexographic element of claim 1, wherein the flexible support is a flame-treated polyethylene terephthalate film. 12. A flexographic element according to claim 1, wherein the flexible support is aluminum. 13. The flexographic element according to claim 1, wherein the flexible support is a polyimide film. 14. The flexible support is tinned steel;
A flexographic element according to claim 1. 15. The flexographic element of claim 1, wherein the photosensitive layer is 0.0005 to 0.250 inches thick. 16. The flexographic element according to claim 1, wherein the photosensitive elastic composition contains a plasticizer. 17 The plasticizer is polyethylene sebacate,
A flexographic element according to claim 16.