CA1045880A - Support for liquid photosensitive resin - Google Patents

Abstract

ABSTRACT
A support for a photosensitive resin for use in making a printing plate using a liquid photosensitive resin. The support comprises a flexible self-supporting base plate and an adhesive layer formed thereon for applying a layer of the photosensitive resin. The adhesive layer is formed from a composition consisting of (A), (B) and (C), or (A), (B') and (C), or (B) and (C), (A) and (B') or (B) and (B') shown below (A) a compound containing at least two 1,2-epoxy groups in the molecule, (B) a compound containing an effectively photopolymerizable unsaturated carbon-to-carbon double bond and a 1,2-epoxy group in the molecule and having a boiling point of at least 120°C., (B') a compound containing an effectively photopolymerizable unsaturated carbon-to-carbon double bond and an amino group in the molecule and having a boiling point of at least 120°C., (C) a curing agent.
A printing plate made with this support stands up very well to the conditions of printing in that it resists melting when heated and it is not easily attacked by printing ink or solvent.

Description

lV45880 ~ his invention relates to a flexible support for preparing a printing plate consisting of the support and a layer o~ a linuid photosensitive resin applied in situ to the support ~nd solidified upon exposure, especially to a support including an adhesive layer for firmly bondin~ the solidified photosensitive resin layer to the support.
Photosensitive resin plates for use in relief printing plates have been previously known. ~hese plates are usually composed of a base of a metal plate or plastic sheet, an adhesive layer (for facilitating the adhesion of a photosensitive resin layer to the base plate), and a ;; photosensitive layer. Generally, an antihalation layer is provided between the adhesive layer and the base. The ; adhesive la~er should not contain a component which prevents the photosensitive resin layer from polymerizing by li~ht or initiates the polymerization in the absence of light, ; and shoul~ also be firmly bonded to the support so that there will be no separation of relief from the support during printing. ~urthermore, the adhesive layer is required to maintain its adhesive strength against influences encoun-tered during the piate making or printing process, such as the temperature, humidity, solvent.
In order to improve the chemical resistance of the sdhesive layer, there has already been proposed a technique whereby a cross-linked partially hardened barrier layer is provided between the adhesive layer and the photosensitive resin layer (Jap~nese Patent Publications Nos. 23761/61 and 12104/65). ~his technigue is inten~ed to prevent the re-duction o~ the adhesive strength of the adhesive layer which - . ~ :, '.' .' , -, : :
.. .

:
~ ~5 ~ 8 0 occurs as a result of the~attackin~ of the cohtact surface between the photosensitive resin layer and image relief areas by a developing solution when washing out the uncured portion of the photosensitive resin. This method, however, r 5 is economically disadvantageous because troublesome control of the conditions for coating a barrier wall forming composi-tion on the adhesive layer and partially har~ening the bar-rier wall layer. Furthermore, the polymeriz~tion reaction taking place during the formation of the barrier wall layer renders the thin base plate miserably warped, and frequentl~
causes marked disadvantages in thQ subsequent operations.
An object of this invention is to provide a sup-port useful for making a printing plate which is not melted ~, by heating and is not easily attacked by water, acid, alkali, i~ 15 organic solvents, or printing ink, and in which reliefs com- -~ posed of a photosensitive resin are firmly bonded to the ! ~upport by an adhesive layer.
- Another object of this invention is to provide a support useful for ma~ing a printing plate which does not break even by the repetition of external forces and has superior resistance to printing.
- Still another object of this invention is to pro-vide an adhesive composition capable of forming an adhesive layer which is not melted by heatin~ and is not attackèd by water, acid, alkali, organic solvents or printing ink, secures a firm bonding Or reliefs composed Or a photosensi_ ;
tive resin to the support, and is not separated by repeated , . .
external forces exerted bn the printing plate.
The above objects of this invention can be 1~45880 achieved by a support for a photosensitive resin for use in making a printing plate using a liquid photosensitive resin, said support comprising a flexible self-supporting base place and an adhesive layer formed thereon for support-ing a layer of the photosensitive resin, wherein said adhesive layer is a three-dimensional cured product containing 1 x 10 4 to 1 x 10 2 mol/g of the effectively photopolymerizable unsaturated carbon-to-carbon double bond, which product has been cured three-dimensionally by the reaction, upon heating, of a composition consisting of (A), (B) and (C) or ~A), (B') and (C), or (B) and ~C), (A) and ~B') or (B) and ~B') shown below ~Aj a compound containing at least two 1,2-epoxy groups in the molecule.
~B) a compound containing an effectively photopolymerizable unsaturated carbon-to-carbon double bond and a 1,2-epoxy group in the molecule and having a boiling point of at least 120C., CB') a compound containing an effectively photopolymerizable unsaturated carbon-to-carbon double bond and an amino group in *he molecule and having a boiling point of at least 120C., (C) a curing agent.
Examples of preferred compounds having at least two 1,2-epoxy groups in the molecule L~omponent ~A ~ are linear polycondensation products formed between epichlorohydrin and polyhydric phenolic compounds, for example, epoxy resins, having a molecular weight of 400 to 4,000 obtained by condensing 2,2-bis~4'-oxyphenyl) propane ~i.e., bisphenol A) with epichlorohydrin in an alkali solution, epoxy resins obtained from novolac resins synthesized from phenol and formaldehyde, and epichlorohydrin, or epoxy resins obtained by condensing a condensate of resorc mol and acetone.
with epichlorohydrin .

~ ~ 4 -,-- : ' ~ , G
~ :
~ - .
~.. " . .. .. . ~ ... . . . .... .. ...... . .

.. .. . . . ...

l~S880 in an alkaline solution.
Cf these, linear polycon~ensation products of t~e following formula, in which n is O or at least 1, formed b~tween bis-phenol A and epichlorohydrin are especially preferred.

C ~-/CHCH2~ 0 ~ C ~ CC~I28HCH23 0 ~ C ~ 2 \ / 2 Other examples including a compound of the follow-ing formula ~ CH O C ~ `
0_1 , 0~ ~ 0 (prepared by subjecting butadiene ~nd crotonaldehyde to a ;~
~, 10 Diels-Alder reaction, ~nd condensing two molecules of the .
resulting 4-formyl-3-methyl-cyclohexene, followed by epo-. xidization), vinyl cyclohexene ~ioxide, dipentene dioxide, and diepoxy ester compounds such as diglycidyl 2,6-naphthalene-dicarboxylate, diglycidyl 2,7-naphthalenedicarboxylate, diglycidyl 1,5-naphthalenedicarboxylate, diglycidyl o-phtha-late, diglycidyl isophthalate, diglycidyl terephthalate, , j , .
diglycidyl methylisophthalate, diglycidyl methylterephthalate.
Examples of the compound having an effectively photopolymerizable carbon-to-carbon double bond and a 1,2-epoxy group in the molecule and having a boiling point of at least 120C. ~component (B)~ are glycidyl acrylate, glycidyl methacrylate, glycidyl allyl ether, o-allyl phenyl glycidyl ether, crotyl phenyl glycidyl ether, methallyl ~lycidyl ether, r ,............... . ~ . . . .. .

f . . .

1~1145880 epoxy acryl~te type resins obtained by conAensing a part of the epoxy group of the polyepo~y compoun~ exemplified above as component (A) with acrylic acid or methacrylic acid, epoxy acrylate type resins o~tained by adding acryloyl chloride to the side chain of the polyepoxy compound exem-plified above as co~ponent tA), especially an epoxy resin obtained by the condensation of bisphenol A and epichloro-hydrin, and polyepoxy compounds obtained by epoxidizing some ` of the many carbon-to-cflrbon double bonds present in poly-butadiene obtained by anionic polymerization.
Of these, glycidyl acrylate, glycidyl methacrylate and epoxy acrylate type resins are used preferably.
Examples of the compound having an effectively photopolymerizable carbon-to-carbon double bond and an amino grou~ and having a boiling point of at least 120C. ~com-ponent (B')~ are reaction pro~ucts of the component (B) with amine curing agents to be ~escribed in detail, preferably reaction products obtained by reacting glyci~yl acrylate, glycidyl methacrylate or glycidyl allyl ether with a part of the active hydrogens of poly~mines such as hexamethylene diamine, more preferably reaction products formed between glycidyl methacrylate and polyamide resins.
The term "effectively photopolymerizable carbon-to-carbon double bond", as used in the present specification R
and appende~ claims, denotes CH2=C wherein R is a hydrogen atom or ~n alkyl group, that is, an a-substituted vinyl group.
In the present invention, ~nown curing agents for epoxy resins, for example, co~poun~s having at least two ;~
- ' ~ : ' ' ~ . :

:
: - .- . .
. . . , ' .: . :

- ) ~¢~45880 active hy~rogen ~toms in the molecule, acid anhydrides, poly-carboxylic acids, or tertiary amines, can be used as the ~ -curing agent tcomponent (C)~ without any particular restric-tion. Examples of the curi~g a~ents usable in this invention are aliphatic amines such as ethylene diamine, diethylene triamine, or diethylaminopropylamine, hydroxyamines such as monoethanolamine, diethanolamine, r~-methylethanolamine or aminoethylethanolamine, aromatic amines such as metaphenylene diamine, or p,p'-diaminodiphenylmethane, amines obtained by replacing a part of the active hydrogens of these amines by an aliphatic or aromatic radical, such as N,N-diethyl ethylenediamine, or dimethyl p-toluidine, acid anhydrides ~; such as phthalic anhydride, maleic anhydride, hexahydro-phthalic anhydride, dodecenylsuccinic anhydride, pimelic - 15 anhydride, or hexachloro-endomethylenetetrahydrophthalic anhydride.
~ he use of the acid anhydride makes it possible to increase the thermal resistance of the adhesi~e layer of -~ ths support. Preferably, the acid anhydride is used together with a small amount of an amine or an alcohol.
Examples of other usable curing agents include polycsrboxylic acids such as phthalic acid, phenol resins, urea resins, polyester resins, polysulfide resins, melamine resins, polyamide resins, polymeric compounds having many active hydrogens, such as polyamines, tertiary amines such as triethylamine or benzyldimethylamine, organic amine complex salts such as trialkalnolamine boric acid salts, and metal compounds such as (C4Hg)2~n(0cOcll~I23)2~ ~ ( 4 9 4 2 - or (C4H90)4~

':

1~4~880 Of these curing agents, an amino-terminated polyamide resin obtained by the condensation of an aliphatic dicarboxylic acid with ethylene diamine an~ having a degree of polymeriza-tion of ~ to 20 is especially useful because of its ability to provide moderate affinity between the cured film on the support and the liquid photosensitive resinO
The adhesive layer of the support in accordance with this invention is a cured three-dimensional polymer formed by applying a composition consisting of components (A), (B) and (C), or (A), (B') and (C), or (B) and (C), (A) and (B') or (B) and (B') to the surface of a flexible self-sup-porting base plate, and allowing the individual components to react with each other. The three-dimensional polymer contains effectively photopolymerizable unsaturated carbon-to-carbon - 15 double bonds in an amount of 1 x 10 4 to 1 x 10 2, preferably 7 _'~
; 1 x 10-~ to 4 x 10 ~. per ~ram of polymer.
; - ~he proportions of the components vary according to the combin~tions of the components. In a composition consisting of components (A), (~) and (C), the proportion of ; 20 component (A) is 10 to 70,/1 by weight, the proportion of com-ponent (~) is 10 to 88,~ by weight, and the proportion of component (C) is 2 to 80,h by wei~ht, the sum of the propor-tions of these three components being 100/, by ~eight. ~he prefPrred proportion is 30 to 60,~ by weight for component (h), 30 to 68% by weight for component (B), and 2 to 40~? by weight for component (C). In a composition consisting of co~ponents (A), (B') and (C), the proportion is 10 to 70',?h by weight, preferably 30 to 60,~ by weight, for compon~nt (A), 30 to 89~ by weight, preferably 30 to 69~ by weight, for component . ..
, .

., : , . . ,. - ~ ~

~ ~ ( lQ4581~0 (B'), and 1 to 6~' by weight, preferably 1 to 4~ by weight, for component (C), the sum of the proportions of these three components being 10~/o by weightO In a composition consisting of components (B) and (C), the proportion is 10 to 98/~ by 5 wei~ht, preferably 30 to 98% by weight, for component (B), and 2 to 9~k by weight, preferably 2 to 7~h by weight, for component (C). In a composition consisting of components (A) . or (B) and (B'), the proportion is 10 to 9~' by weight, pre- `
ferably 30 to 7~,~ by weight, for component (A) or (B), and 90 to 1~'. by weight, preferably 70 to 30/~ by weight, for component (B').
The components are mixed in the above-specified proportions by well known methods to provide a liquid com-position suitable for coating on the surface of the base plate .
.-~ 15 by well known methodsO
~he coa~ing of ~he compos~ti.on is facilitated by dissolving it in an easily volatile solvent. Examples of the solvent are aronatic hydrocarbons such as benzene, toluene, oe xylene, alcohols such as n-butanol or diacetone alcohol, ketones such as acetone, methylethyl ketone or .~ methylisopropyl ketone, and acetic acid ~sters such as ethyl acetate or butyl acetate.
If desired, it is possible to incorporate in the composition an ionic addition-reaction catalyst, or a ra~ical ; 25 polymeriz~tion inhibitor. : :
The composition coated on the surface of the base plate can be converted to a three-dimensional cured polymer by heating it at 50C. to 180C., preferably 80C. to 130C.
This conversion is substantially completed within about 3 to -:

- ~ .
. . . .

' ' 1~45880 - 30 minu~es to form a hard non-tacky a~hesive layer. The composition m~y be aged for 10 to 120 hours at room tempera-ture to 40C. before the above heating.
~he thickness of the adh~sive layer is usually 5 to 100 microns to achieve the purpose sufficiently.
The amount of the unsaturated carbon-to-carbon double bond contained in the adh~sive lay~r after conversion ` to a three-dimensional cured polymer can be controlled ac-cording to the proportion of the component (B) or (B') used, its structure, and the speed of drying.
~he flexible self-sup~orting base plate to be used in this invention may, for example, be a metal plate of iron, stainless steel, zinc or aluminum, a rubber sheet of natural ; or synthetic rubber, and a film or sheet of cellulose, a cellulose derivative, a polyolefin, a polyester, a polycarbo-nate or a polysulfone, papbr, or a cloth Godd bon~
strength is obtained with the metal plates such as iron, stainless steel or aluminum, and therefore, these metal plates are used especially preferably. The preferred thickness of the base pl~te is 0.1 mm to several millimetersO Films or -: . .
sheets prepared from polymers of photo-polymerizable composi-tions can also be used.
A filler or reinforcing agent can be incorporated in the base plate. l~hen a base plate which reflects light to , a high degree, such as ~etal plates, is used, the light that has passed through the photosensitive resin layer formed on the support irradiates the surface of the support at any angle ;` ~xcepting 90, and reflects, after which it causes polymeri-zation at areas free from images. When such a base material ': : :"

- 10 - ,~ , , ", ;
-- `

- , ' - . ~ ; ' ., ': , ' :
-, :, .. : . : . - , : . . . -1~45~80 is used, it is recommende~ to mix a light absorbing agent sufficient for absorbing at least about 50% of the incident actinic light with the three-dimensional polymer layer (adhesive lflyer), or to form an antihalation layer on the surface of the base plate.
The base plate in the pres~nt invention also denotes - such a base plate on which an antihalation layer is provided.
~ he light absorbing agent so mixed or contained in the antihalation layer may either be colorless or colored.
Examples of suitable light absorbing agents are inorganic or organic pigments having absorption in the near ultraviolet region, such as carbon black, trilead tetroxide, titanium dioxide, organic polyazo pigments, benzidine yellow, i and Rhodamine, and also benzophenone or benzotriazole com-pounds which have previously been known as effect ve ultra-violet absorbents.
~ he adhesive layer so obtaine~ of the support of this invention is very tough, and the adhesive layers do not break or become tacky when the supports ~re contacted with each other or stacked in usual handling.
A photosensitive resin plate can be prepared by applying a photopolymerizable photosensitive resin composition to the surface of the support of this invention by known methods such as co?ting, squeezing, spraying or laminating to form a coating of u~iform thickness. A photosensitive resin composion suitable for preparing a relief printing plate contains a compound havin~ a radical addition-polymeri-zable unsaturated carbon-to-carbon double bond and a photo-polymerization initiator activating the above compound by .

- -- 11 -- .

lU~S880 light, ~nd if desired, a solvent-soluble high-molecular-weight polymer for supporting the above co~pound, for example, a cel-lulose derivative such as a cellulose ~ster or cellulose ether, or a polyolefin such as polyvinyl alcohol, a polycondensate such as a polyamide or polyester. Such a photosensitive resin composition is well known.
A relief printing plate is produced from the resul-ting assembly composed of the photosensitive resin layer, adhesive layer and the support by exposing the photosensitive resin layer through a transparent negative film having image areas, and then tr~ating the exposed layer with a suitable solvent. The exposed portion of the photosensitive resin layer polymerizes substantially integrally with the radical addition-polymerizable unsatur~ted carbon-to-carbon double ~o~
contained in the adhesive layer and the unsaturated carbon-to-carbon double bon~ contained in the photosensitive resin composition, and becomes solvent-insoluble, and at the same time, these are firmly adhered to each other. The unexposed portion does not undergo polymerization, and is therefore removed by the solvent. Thus, a printing plate which can be i immediately serviceable on a printing press is obtained. The adhesion of the support to the remaining reliefs is very strong, and is not attacked by the printing ink or solvent. ~here-fore, the printing plate obtained has very superior resistance to printing, and permits printing of several hundred thousand ~; copies.
The following EXa~ples illustrate the present inven-tion in greater detail.
,"
- . ,,'' "
- 12 ~

. .---1 t 1~45880 Example 1 A tin-pl~ted steel plate havin~ a thickness of 0.3 ~m was coeted lith an epoxy l~c~uer ("~ ITE", the product of Toa Paint Kabushiki Kaisha, Japan) containing red lead using a bar co~ter, and heat-treated for 20 minutes using hot air at 1~0C. ~Ihile drivin~ off the solventO A 25 ~
thick primer layer having an antihalation effect was thus formed. A clear epoxy lacquer containing glycidyl methacrylate was blo~m against the ~ntihalation lay~r using a spray ~
While gradually driving off the solvent, the plate was heat treated for 20 minutes at 100C. to form a 15 ~ thick non-tacky topcoat layer. ~he details of the epoxy lacquers used for providing the primer layer and the topcoat layer were as follows :
~-~ lac~u~r for the prim r _a~er The lacquer ~as a uniform solution or dispersion of 20 parts by weight of an epoxy resin having an e~ox~ equiva lent of 4 x 10-~ eq./gr. and an average molecular ~eight of about 500 which had been obtained by the condensation of bis-phenol A with epichlorohydrin, 15 parts by weight of analiphatic polyamide resin with terminal a~ino groups having an amine eguivalent of 1 x 10 eq./gr. and about 20 parts by weight of red lead, in a thinner consisting mainly of toluene, diacetone alcohol and n-butanol. The lacquer had a solids content Or about 6~'~. In actual use, however, a primer solu-tion containing the epoxy resin and the red l~acl and a primer solution cont~inin~ the polyamide resin were obtained separa-tely, and mixed in the above proportions immediately before - use.
..;
TRADE~RK
13 - ;

BI ~

l~S~80 oxy lacquer for the topcoat la~er The lecquer Tas prepared by mi~ing 40 parts of a solution containing 5~' by weight of the same epoxy resin as used in the primer, 50 p~rts by weight of a solution contain-ing 40,b by weight of the same polyamide resin as used in theprimer, 30 parts by weight of glycidyl methacrylate, and 20 parts by weight of the same thinner as used in the primer, several hours before use. Thus, the resulting top coat layer contained about 3 x 10 3 mol per gram of the coating of a CE~
vinyl ~roup (CH2=C- derived from the glycidyl methacrylate).
The support prep&red above was then coated to a thickness of 0.7 mm with a viscous liquid photosensitive ~ resin having a viscosity at 20C. of about 50 poises and com--~ prising a uniform mixture of 70 parts by weight of an unsa-turated polyester resin having an aci~ value of 1~0 and ob-tained by heating 2 ~ols of fu~aric acid, 1 mol of trimel-litic anhydride, 1.5 mols of ethylene glycol and 1.5 mols of diethylene glycol, 2~ parts by weight of polyethylene glycol diacryl~te (the polyethylene glycol units ha~ing a degree of polymerization of 4), 1 part by weight of benzoin methyl ether, and 0.01 part by weight of hydroquinoneO The coated - support was exposed for 5 minutes to actinic light from an ultraviolet fluorescent lamp through an image~bearing ~egative film, and then washed with dilute aqueous alkali to form a relief printing plate. Even after printing 500,000 copies using this printing plate, the separation of the resin layer was not observed.
On the other hand, a printing plate was prepared in : .

..
- 14 _ . .

~ r . . . .

the same way as above except that the adhesive layer was formed using a clear epoxy lacquer not containing glycidyl methacrylate. In the resulting printing plate, the adhesion between the photosensitive resin and the support was very weak, and reliefs in halftone dots, especially small dots or line relief separated from the support merely by touching them with a finger. When 10,000 copies were printed usingthis pri~ting plate, the relief portions in halftone dots, fine line relief or small independent dots separated fr~m the su-port, and the printing plate was quite useless.
Example 2 A 0.2 mm thick aluminum plate was coated to a thickness of 30 microns with an epoxy lacquer (Eton*No. 2100) containing cyanine green, and immediately heat-treated at 120C. for 30 minutes to form an adhesive layer containing an antihalation agent. The adhesive layer contained about 1.5 x 10 3 mol/gr. of a methylvinyl group.
The epoxy laxquer used above was prepared as follows:
20 parts by weight of an epoxy resin having a molecular weight of about 1100 and obtained by condensing bisphenol A with epichlorohydrin in an alkaline solution, 15 psrts by weight of a reaction product of hexamethylene diamine and glycidyl methacrylate in a mol ratio of 1:2 (a viscous liquid obtained by dissolving the hexamethylene diamine and glycidyl methacrylate in a mol ratio of 1:2 (a viscous liquid obtained by dissolving the hexamethylene diamine and glycidyl methacrylate in a mixed solvent consisting of toluene, n-butanol and methyl cellosolve to a solids concentration of 30% by weight, and gradually heating them in the presence of methoxy phenol as an anti-gellation agent), 2 parts by weight * TRADE MARK -15-~04S~380 of ethylene diamine as a curing agent, 7 parts by weight of cyanine green as an antihalation agent, and 80 parts by weight of a mixed solvent consisting of toluene, n-butanol and methyl cellosolve*were mixed to prepare the lacquer. The lacquer was coated on the support immediately after prepara-tion.
For comparison, the same procedure as above was repeated except that 2 parts by weight of p-phenylene diamine was used instead of 15 parts by weight of the reaction product formed between hexamethylene diamine and glycidyl methacrylate.
Reliefs of the photosensitive resin had poor ad-hesion, and separated rom the support even by weak stress.
This is because the coating of the support did not contain an active double bond.
Exam~le 3 Using the same epoxy resin used for the primer in Example 1 and the reaction product of 2 mols of hexamethylene diamine and 3 mols of allyl glycidyl ether (reacted in the same way as in Example 2 in the presence of methoxy phenol as -a polymerization inhibitor), a lacquer of the following for formulation was prepared.

, * TRADE NARK

Formulation arts b~ *ei~ht Epoxy resin 20 Reaction product of hexa-methylene diamine and allyl glycidyl ether 20 Red iron oxide 5 Red lead 15 N,N-diethyl ebhylene diamine as a curing agent 0.5 Thinner (mixed solvent consisting of toluene, diacetone alcohol, butyl acetate, and butanol in a ratio of 40:20:20:20) 240 The resulting lacquer was coated on a 0.15 mm thick polyethylene terephthalate sheet which had been sand blasted, using a bar coater, and then the solvent was driven off.
After evaporation of the solvent, the amount of the coating was about 7 g per m . The coated sheet was heated-treated for 60 minutes in a hot air dryer held at 80C., whereupon the coating became non-tacky at the surface. The coating con-tained about 2 x 10 3 mol/gr. of a vinyl group.
Gn the other hand, 30 parts by weight of a copolymer of methyl methacrylate and methacrylic acid (in a mol ratio of 70:30), 30 parts by weight of tetraethylene glycol dimetha-crylate, 30 parts by weight of trimethylol propane trimetha-crylate~ 10 parts of polyethylene glycol having a molecular weight of 100,000,;2 parts by weight of benzoin ethyl ether, and 0.03 part of methoxyhydroquinone were mixedbo form a photo-sensitive resin which was liquid at room temperature.
The resulting resin was coated uniformly on the support to a thickness of 0.5 mm, and after drying, exposed for .~ ~
,: :

, .

-about 5 minutes to an actinic light from eight 20 watt fluorescent chemical lamps through an image-bearing negative film. The distance between the photosensitive resin plate and the lamps was 10 cm. Then, the exposed plate was washed out with a 0.3% aqueous solution of sodium hydroxide at 40C.
rhe resulting printing plate was adhered to a prin-ting cylinder using an adhesive tape, and printing was per-formed. The printing plate gave 300,000 printed copies in perfect condition, and was resistant to washing with an wash-10in8 oil which was carried out during printing.
Example 4 30 Parts by weight of benzidine yellow was added to 100 parts by weight of the same Epilite clear solution -(containing 50% by~weight of the epoxy resin~ as used in the topcoat in Example 1, and they were thoroughly mixed by mil-ling. Separatelj, 16 parts by weight of glycidyl methacrylate was reacted with 100 parts by weight of the same Epilite clear solution (containing 40% by weight of the polyamide resin) as used for the topcoat in Example 1, in the presence of 0.2%
20by weight of hydroquinone at a temperature of 130C. for 60 minutes to form a polyamide resin having a double bond.
(a) A lacquer was prepared by mixing 100 parts by weight of the solution prepared above and containhng the yellow pigment, 85 parts by weight of the polyamide resin solution prepared above, and ~11 part of triethylene tetramine as a curing agent.
Immediately after preparation, the lacquer was coated on a 0.3 mm thic~ polycarbonate film to a thickness of 5 microns, and the solvent was driven off. Furthermore, the ~ ," . . ':
-18_ ! ~

~1 lQ45880 coated film was heat-treated for 1~ minutes at 100C. ~he resulting co?ting ~Jas non-tacky. The adhesive coating con-tained about 7 x 10 4 mol/gr of a methylvinyl group.
(b) A lacquer solution ~ras prepared in the same way as in (a) above except that triethylene tetramine was not added.
The solution was a@ed for about one day at room temperature, and coated in the s~me way as in (a) above. Then, the coating was cured by h~ating under the same conditions as in (a) above.
~ In each of (a) and (b) ~bove, the support prepared exhibited a very superior adhesive effect as a s~pport for a printin~ plate of an unsaturated polyester type photosensitive resin same as used in Example lo Example 5 The procedure of Example 1 was repeated except that .
! 15 the lacquer for the top coat used in Example 1 was aged for two days at 30CC. after preparation. In this case, even when the lacquer was dried with hot air imme~iately after its `~ application, the glycidyl methacrylate was completely fixed to the coated film. Another precise experiment showed that the coated fil~ contained about 5 x 10 3 mol/grO of a methyl-vinyl groupO ~he adhesive strength of the resulting adhesive layer to the photosensitive resin was very superior as in -~ Example 1.
On the other hand, the procedure of Exam~le 1 was repeated except that immediately after spraying the top coat ~ -lacquer on the support, it was heated for 20 minutes in a hot air duct held at 100C. while driving off the solvent. ~he ~ , .
resulting coated film was about 13 ~icrons in thickness, and was non-tacky. However, the coating obtained had a methyl-- ~ :
~- 19 _ r ;

.. . .

.

10~58i~0 vinyl group content of less than 10 4 mol/gr. probably be-cause the glycidyl ~ethacrylate was driven off in a considerable amount as a result of heating the coating immediately after application.
Example 6 A 0.27 mm thick steel plate having a chromic acid-treated surface was coated with the same primer lacquer and the topcoat lacquer used in Example 5. The resulting support was coated with a clear liquid photosensitive resin consisting ~ -of 35 parts by weight of methyl cellulose~ 65 parts by weight of triethylene glycol diacrylate, 3 parts of anthraquinone and 0.03 part of hydroquinone. The resin plate was exposed through an image-bearing negative film, and washed out in the same way as in Example 5.
; A portion of the resulting printing plate containing a relief image (line relief having a height of 0.7 mm, a width of 100 microns, and a length of 5 mm) was cut out as a test sample, and the tensile strength required to separate the relief image from the support in the vertical directi~on was measured. It was ound that when the support plate was not aged, the tensile strength required for separation was

2 Kg/5 mm relief, and ~hen the support plate was aged, it was ô Kg/5 mm relief.
Examples 7 and_8 --Epikote *1001 (tradename for the product of Shell Chemical Co., an epoxy resin synthesized from bisphenol A and epichlorohydrin and having a molecular weight of about 900 and epoxy groups at both ends of the molecular chain) was dissolved in the same solvent as used in Example 1 to form a 20% by ~ , * TRADE MARK

-20_ .

- ~4S880 weight solution. Methacrylic acid was added to t~e solution in an amount of 1/2 equivalent based on the epoxy groups pre-sent in the epoxy resin. As a polymerization inhibitor~ Oo~h by weight based on solids con~ent of N-nitrosodiphen~lamine was a~ded, and the about l~/o by weight based on solids content of LiCl as a catalyst was added. The mixture was reacted at 60 to 80C. for about 4 hours. Samples of the product was occasionally withdrawn from the reaction system, and the acid ' ~ v~lues of the samples were measured to trace the reaction.
Using the resulting epoxy acrylate resin containing both an epoxy group and a vinyl group, lacquers for an ad-- hesive layer were prepared in accordarlce with the following ' formulations.
S Formulation of the lacquer for Example 7 Parts by weight Epikote ~34 (æn epoxy resin having a molecular weight of about 450 and derived from bisphenol A and epi-chlorohydrin) 10 Epoxyacrylate resin 15 Polyamide resin curing agent used iIl Example 1 15 Red lead 10 ' . ~

., ' , .
, - 21 - ~

, '. ' ' - ~

l~J4S880 Fo mulation of the lacquer for Example 8 . Parts b~ weight Novolac-epoxy resin (having ~ viscosity of 3800 centi- .
poises at 25C. an~ a molecular weight of about 390, and containing 2.1 epox~ OEoups on an average per molecule) 10 Epoxyacrylate resin 15 Polyamide resin curing agent used in Example 1 15 Red lead 10 Thinner used in Example 1 the amount such that the concentration of the solution is - 4~/0 by weight Each of the two lacquers ~as coated in a customary ! manner on the same support as used in Exa~ple 6 to a thickness. 10 of about 20 micronsO The curing time ~ras about 15 minutes at llOCC. The resulting coating i~medi~ely after curing . ~as non-tacky and of superior quality, but was further com- .
- pletely cured.after allowing it to stand ~t room temperature for 1 week. ~he amount of a methylvinyl group contained in each one gram of the coating was about 3 x 10-4 mol in each of these Examples. .
Then, using the same unsaturated polyester-type liquid photosensitive resin as used in Example 1, print mg plates having relief images were prepared as in Example 6.
The tensile strength required to separate the relief images fro~ the support was measured, and found to be 5 to 7 Kg/5 m~. relief in each of the ~amples. This means that the printing plates can be sufficiently serviceable.

,' - 22 - ~ -- ~ --- - . . :.. ,, ~

~ 945~30 Exam~le 9 A lacquer was prepared from 20 parts by weight of the same epoxy resin used in Example 1, 20 parts by weight of the same epoxyacrylate resin as synthesized in Example 7, 10 parts by weight of the same polyamide resin curing agent as used in Example 1, and the same thinner as used in Example 1 ~in an amount such that the solids concentration of the lacquer became 40%
by weight). The resulting lacquer was applied as a topcoat in a thickness of about 10 microns to the same support as used in Example 1 which had been coated with the primer and the antihalation layer. The solvent was driven off, and the coating was cured sufficiently for 30 minutes in hot air at ; 10 110C.
The topcoat of the resulting support contained about 4 x 10 4 mol/gr of a methylvinyl group.
The same liquid photosensitive resin as used in Example 1 was coated on the resulting support, and reliefs were provided on it imagewise in a customary manner, to form a printing plate. It was found that very clear printed copies could be obtained using this printing plate even after one million copies were printed on it.

- 23 _ .- ~ :~ : . . - .'. , : :

Claims (10)

THE EMBODIMENTS OF TIE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A support for a photosensitive resin for use in making a printing plate using a liquid photosensitive resin, said support comprising a flexible self-supporting base place and an adhesive layer formed thereon for support-ing a layer of the photosensitive resin, wherein said adhesive layer is a three-dimensional cured product containing 1 x 10-4 to 1 x 10-2 mol/g of the effectively photopolymerizable unsaturated carbon-to-carbon double bond, which product has been cured three-dimensionally by the reaction, upon heating, of a composition consisting of (A), (B) and (C) or (A), (B') and (C), or (B) and (C), (A) and (B') or (B) and (B') shown below (A) a compound containing at least two 1,2-epoxy groups in the molecule.
(B) a compound containing an effectively photopolymerizable unsaturated carbon-to-carbon double bond and a 1,2-epoxy group in the molecule and having a boiling point of at least 120°C., (B') a compound containing an effectively photopolymerizable unsaturated carbon-to-carbon double bond and an amino group in the molecule and having a boiling point of at least 120°C., (C) a curing agent.

2. The support of claim 1 wherein said component (A) is a linear polycondensation product formed between epichlorohydrin and a polyhydric phenolic compound.

3. The support of claim 1 wherein said component (B) is a member selected from the group consisting of glycidyl acrylate, glycidyl methacry-late and an epoxyacrylate resin.

4. The support of claim 1 wherein said component (B') is a reaction product formed between said component (B) and an amine curing agent.

5. The support of claim 1 wherein said curing agent is a polyamide resin.

6. The support of claim 1 wherein the proportion of said component (B) or (B') is 0.5 to 5 times the weight of said component (A).

7. The support of claim 1 wherein said adhesive layer is a cured product formed from said composition consisting of 10 to 70% by weight (A), 10 to 88% by weight (B) and 2-80% by weight (C).

8. The support of claim 1 wherein said adhesive layer is a cured product formed from said composition consisting of 10 to 70% by weight (A), 30 to 80% by weight (B') and 1-60% by weight (C).

9. The support of claim 1 wherein said adhesive layer is a cured product formed from said composition consisting of 10 to 98% by weight (B) and 2 to 90% by weight (C).

10. The support of claim 1 wherein said adhesive layer is a cured product formed from said composition consisting of 10 to 90% by weight (A) or (B), and 90 to 10% by weight (B').