CONSTRAINED N-ALKYLAMINO ARYL KETONES AS SENSITIZERS FOR PHOTOPOLYMER COMPOSITIONS

Abstract: Photopolymerizable compositions comprising (a) at least one ethylenically unsaturated compound, (b) at least one organic polymeric binder, (c) optionally at least one photoinitiator and (d) at least one constrained N-alkylamino aryl ketone compound as defined, e.g., bis (6-julolidyl ketone), bis-(N-­ ethyl-1,2,3,4-tetrahydro-6-quinolyl)ketone, etc. The composi­ tions, in layer form, are useful in photoresists, including pro­ jection speed photoresists, printing plates, drafting and ton­ ing films, etc.

Description: TITLE CONSTRAINED N-ALKYLAMINO ARYL KETONES AS SENSITIZERS FOR PHOTOPOLYMER COMPOSITIONS DESCRIPTION TECHNICAL FIELD This invention relates to photopolymerizable compositions. More particularly this invention relates to photopolymerizable compositions containing constrained N-alkylamino aryl ketones capable of increasing the speed of polymerization. BACKGROUND ART Photopolymerizable compositions are widely used for an increasing number of usages. For example this type of composition is now commercially used in printing, copying, resist formation, etc. Such compositions generally contain an ethylenically unsaturated compound or other type polymerizable compound. a photoinitiator or photoinitiator system and preferably a solvent-soluble or aqueous or alkaline soluble organic polymeric binder compound. Many of the known useful photopolymerizable compositions, however, are limited in applicability because the initiators are not as active as desired. Chambers U.S. Pat. No. 3,479,185 discloses photopolymerizable compositions containing an ethylenically unsaturated monomer, a free radical producing agent such as an amine substituted leuco triphenylamine dye and a hexaarylbiimidazole. These compositions are photoinitiatable in the ultraviolet region of the spectrum. Chambers, however, found that by adding energy-transfer dyes of the xanthene and acridine classes the sensitivity of the photopolymerizable compositions was extended into the visible spectral region with an increase in speed of polymerization. Chang U.S. Pat. No. 3,549,367 discloses photopolymerizable compositions containing hexaarylbiimidazoles and p-aminophenyl ketones, e.g., Michler's ketone, which increase the speed of polymerization of the compositions. While the aforementioned compositions have provided improved photopolymerizable compositions, there is a need to provide photopolymerizable compositions having improved photospeed. DISCLOSURE OF THE INVENTION In accordance with this invention there is provided a photopolymerizable composition comprising an admixture of (a) at least one nongaseous ethylenically unsaturated compound having at least one terminal ethylenically unsaturated group, a boiling point above 1000C at normal atmospheric pressure and being capable of addition polymerization, (b) at least one organic polymeric binder compound, (c) optionally at least one photoinitiator or photoinitiator system, the improvement wherein the composition contains (d) 0.001 to 15% by weight of the total composition of at least one constrained N-alkylamino EMI2.1 formula: wherein R1 and R5 are H, R2 is lower alkyl of 1 to 4 carbon atoms, R3 is lower alkyl of 1 to 4 carbon atoms, R4 and R7 are H, R6 is H, OCH3 or N-R8 t R8 is lower R9 alkyl of 1 to 4carbon atoms, Rg is lower alkyl of 1 to 4 carbon atoms, R1 and R2 taken together is -CH CH CH -, R and R taken together is -CH CH CH -, R 222 3 4 222 5 and R8 taken together is -CH2CH2CH2 -, R7 and R9 taken together is -CH2CH2CH2 - and Z is H-, H- or a bridge between the two aromatic rings taken from the group of EMI3.1 -O-, -S-, with the proviso that when Z is H- , H- at least one of R1 and R2, R3 and R4, R and R 5 5 8 and R7 and R9 when taken together is -CH CH CH -. 222 The photopolymerizable compositions of this invention comprise (a) at least one ehtylenically unsaturated compound, (b) at least one organic polymeric binder, (c) optionally at least one photoinitiator or photoinitiator system, and (d) at least one constrained N-alkylamino aryl ketone defined above and described more fully below. Other useful additives in the photopolymerizable composition include: inhibitors, leuco dyes, accelerators such as chain transfer agents and oxygen scavengers, as well as inert components such as plasticizers, dyes and pigments to increase visibility of the image, fillers, etc. The ethylenically unsaturated compound (monomer) can be present in the photopolymerizable composition in an amount of 3 to 97 parts by weight, and the organic polymeric binder can be present in an amount of 97 to 3 parts by weight based on the total weight of monomer and binder. The photoinitiator when present can be used in an amount of 0.001 to 20 parts by weight per 100 parts by weight of the combined weight of ethylenically unsaturated compound and binder. The ketone compound can be present in an amount of 0.001 to 15 parts by weight, preferably 0.05 to 5 parts by weight, per 100 parts by weight of the combined weight of ethylenically unsaturated compound and binder. The present in minor amounts known to those skilled in the art. The ethylenically unsaturated compounds (a) (photopolymerizable monomers of this invention) have a boiling point above lOOoC at normal atmospheric pressure and are capable of forming a high molecular weight polymer by photoinitiated. addition polymerization. Suitable compounds are disclosed in Chang U.S. Pat. No. 3,756,827. column 2. line 36 to column 3, line 30, the disclosure of which is incorporated herein by reference. Other useful monomers include ethylenically unsaturated diester polyhydroxy polyethers as described in Chambers U.S. Patent 4,245,031. Examples include the Epocryl# resins sold by Shell Chemical Co. Many of the polymerizable monomers are subject to thermal polymerization, especially when stored for long periods or at elevated temperatures. When such compounds are supplied commercially. it is customary for them to contain a small, but effective. amount of a thermal polymerization inhibitor. These inhibitors may be left in the monomers when the photopolymerizable coating compositions of this invention are prepared. The resulting compositions usually have satisfactory thermal stability. If unusual thermal exposure is anticipated. or if monomers containing little or no thermal polymerization inhibitor are employed. compositions with adequate shelf life can be obtained by incorporating, e.g., up to 0.5 percent, by weight of monomer, of a thermal polymerization inhibitor such as hydroquinone, methyihydroquinone, p-methoxyphenol. etc. Preferred ethylenically unsaturated compounds are tetraethylene glycol dimethacrylate and trimethylolpropane triacrylate. Macromolecular organic polymeric binders (b) present in the photopolymerizable compositions include: (1) copolyesters based on terephthalic, isophthalic, sebacic, adipic and hexahydroterephthalic acids; (2) nylons or polyamides; (3) vinylidene chloride copolymers; (4) ethylene/vinyl acetate copolymers; (5) cellulosic ethers; (6) polyethylene; (7) synthetic rubbers; (8) cellulose esters; (9) polyvinyl esters including polyvinyl acetate/acrylate and polyvinyl acetate/methacrylate copolymers; (10) polyacrylate and poly-a-alkyl-acrylate esters, e.g., polymethyl methacrylate and polyethyl methacrylate; (11) high molecular weight ethylene oxide polymers (polyethylene glycols) having weight average molecular weights from 4000 to 4,000,000: (12) polyvinyl chloride and copolymers; (13) polyvinyl acetal; (14) polyformaldehydes; (15) polyurethanes; (16) polycarbonates; and (17) polystyrenes. In a preferred embodiment of the invention, the polymeric binder is selected so that the unexposed photopolymerizable coating is soluble in predominantly aqueous solutions, for example dilute aqueous alkaline solutions, but upon exposure to actinic radiation becomes relatively insoluble therein. Typically, polymers which satisfy these requirements are carboxylated polymers, for example vinyl addition polymers containing free carboxylic acid groups. Preferred binders include a 1:1 copolymer of styrene/maleic anhydride partially esterified with an isobutanol mixture, e.g., acid no. ca. 190, wt. ave. mol. wt. ca. 10,000; and a combination of a copolymer of styrene/maleic anhydride and a terpolymer of ethyl acrylate/methylmethacrylate/acrylic acid. Another preferred group of binders includes polyacrylate esters and poly-#-alky1-acrylate esters, particularly polymethyl methacrylate. Preferably at least one photoinitiator (c) is present in the photopolymerizable compositions. Useful photoinitiator types include: hexaarylbiimidazole compounds which are preferred. 4-trichloromethyl-4-methyl-2, 5- cyclohexadienones, quinones, alkylaryl ketones, benzophenones, and mixtures thereof. The biimidazoles are photodissociable to the corresponding triarylimidazolyl radicals. These hexaarylbiimidazoles absorb maximally in the 255-275 nm region, and usually show some, though lesser absorption in the 300-375 nm region. Although the absorption bands tend to tail out to include wavelengths as high as about 430 nm, they normally require light rich in the 255-375 nm wavelengths for their dissociation. The hexaarylbiimidazoles can be represented by the formula: EMI6.1 wherein A, B and D represent aryl groups which can be the same or different. carbocyclic or heterocyclic, unsubstituted or substituted with substituents that do not interfere with the dissociation of the hexaarylbiimidazole to the triarylimidazolyl radical or with the oxidation of the leuco dye, and each dotted circle stands for four delocalized electrons (i.e., two conjugated double bonds) which satisfy the valences of the carbon and nitrogen atoms of the imidazolyl.ring. The B and D aryl groups can each be substituted with 0-3 substituents and the A aryl groups can be substituted with 0-4 substituents. Useful 2,4,5-triarylimidazolyl dimers are disclosed in Baum & Henry U.S. Patent 3.652,275, column 5, line 44 to column 7, line 16, the disclosure of which is incorporated herein by reference. Useful quinone types are: camphorquinone, substituted or unsubstituted polynuclear quinones which are compounds having two intracyclic carbon atoms in a conjugated carbocyclic ring system, e.g., 9,10-anthraquinone, l-chloroanthraquinone. 2-chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, octamethylanthraquinone, 1, 4-naphthoquinone. 9, 10-phenanthrenequinone, 1, 2-benzanthraquinone, 2,3-benzanthraquinone, 2-methyl-l, 4-naphthoquinone, 2, 3-dichloronaphthoquinone, l,4-dimethylanthraquinone, 2,3-dimethylanthraquinone, 2-phenylanthraquinone, 2-3-diphenylanthraquinone, sodium salt of anthraquinone alpha-sulfonic acid, 3-chloro-2-methylanthraquinone, retenequinone, 7,8,9, 10-tetrahydronaphthacenequinone, 1. 2,3,4-tetra-hydronaphthacenequinone, and l,2,3,4-tetra-hydrobenz(a)anthracene-7,12-dione. Useful alkylaryl ketones include: vicinai ketaldonyl alcohols such as benzoin, pivaloin, acryloin ethers, e.g., benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin phenyl ether. benzoin t-butyl ether, benzoin sec-butyl ether, benzoin isobutyl ether, benzoin n-butyl ether; a-hydrocarbon-substituted aromatic acryloins, including a-methylbenzoin, a-allylbenzoin and a-phenylbenzoin, benzoin dialkyl ketals such as benzil dimethylketal, benzil ethyleneglycol ketal. benzil, benzoin esters such as O-acetyl benzoin and O-acylated oximinoketones such as l-phenyl-l,2-propanedione-2-O-benzoyloxime. Useful benzophenones include: benzophenone, 4,4 '-dichlorobenzophenone, fluorenone, anthrone, thioxanthenone. xanthenone, Michlerts ketone, 4-dimethylaminobenzophenone, 4-morpholinobenzophenone. 4-Trichloromethyl-4-methyl-2, 5- cyclohexadienone compounds useful in this invention are disclosed in Sysak U.S. Patent 4,341,860, the disclosure of which is incorporated by reference. Useful such compounds include: 4-methyl-4-trichloromethyl-2,5-cyclohexadienone 2,6-dimethyl-4-trichloromethyl-2,5-cyclohexadienone 3,4-dimethyl-4-trichloromethyl-2, 5-cyclohexadienone 4-nonyl-4-trichloromethyl-2,5-cyclohexadienone 4-trichlororethyl-3,4,5-trimethyl-2,5-cyclohexadienone 2,6-di-(t-butyl)-4-trichloromethyl-2,5-cyclohexadienone 2,6-di(t-butyl)-4-methyl-4-trichloromethyl-2,5-cyclo hexadienone 2,6-dichloro-4-methyl-4-trichloromethyl-2,5-cyclo- hexadienone 2,6-dibromo-4-methyl-4-trichloromethyl-2,5-cyclo- hexadienone 2,4-dimethyl-4-trichloromethyl-2,5-cyclohexadienone 4-trichloromethyl-2,4,5-trimethyl-2,5-cyclohexadienone 4-phenyl-4-trichloromethyl-2,5-cyclohexadienone 2-methoxy-4-methyl-4-trichloromethyl-2,5-cyclo- hexadienone 2,6-dimethoxy-4-methyl-4-trichloromethyl-2,5-cyclo- hexadienone 2,3-benzo-4-methyl-4-trichloromethyl-2,5-cyclo- hexadienone 2,4,6-tri(t-butyl)-4-trichloromethyl-2,5-cyclo- hexadienone 4-trichforomethyl-2,4.6-trimethyl-2.5-cy 4-t-butyl-4-trichloromethyl-2,5-cyclohexadienone 2,3,4,5,6-pentamethyl-4-trichloromethyl-2,5-cyclo- hexadienone 2,4,6-tri(t-pentyl)-4-trichloromethyl-2,5- cyclohexadienone 4-benzyl-4-trichloromethyl-2.5-cyclohexadienone 2-t-butyl-4-trichloromethyl-2.5-cyclohexadienone 2-i-propyl-4-methyl-4-trichloromethyl-2,5-cyclo- hexadienone 2-t-butyl-4-methyl-4-trichloromethyl-2 , 5-cyclo- hexadienone 2-ethyl-4, 5-dimethyl-4-trichloromethyl-2, 5-cyclo- hexadienone 2,3-benzo-4,5-dimethyl-4-trichloromethyl-2,5-cyclo- hexadienone Additional useful compounds are similarly substituted -4-dichloromethyl-2, 5-cyclohexadienones as those described above. The ketone compound (d) of this invention have been defined broadly above. Preferred compounds include: 1. bis(6-julolidyl ketone) 2. bis-(N-ethyl-l,2,3,4-tetrahydro-6-quinolyl) ketone 3. p-methoxyphenyl- (N-ethyl-l,2,3, 4-tetrahydro- 6-quinolyl)ketone 4. 2,7-bis-N,N-dimethylaminofluorenone 5. 2,7-bis-N,N-dimethylamino-9,9-dimethyl-10- anthrone. The formulas for the above ketone compounds are as follows: EMI10.1 Other useful constrained N-alkylamino aryl ketones are: EMI10.2 Preparation of diarylmethanes and subsequent oxidation of the desired ketones, such as compounds 1 and 2 above, can be prepared according to the methods of C. Barker and G. Hallas, J. Chem. Soc. (B), 1068 (1969). Procedures for preparing additional sensitizers preceded the examples. Optionally leuco dyes can also be present in the photopolymerizable composition. By the term "leuco dye is meant the colorless ti.e., the reduced) form of a dye compound which can be oxidized to its colored form by the triarylimidazolyl radical. Leuco dyes are disclosed in Baum & Henry U.S. Patent No. 3,652,275. column 7, line 24 to column 11, line 32, the disclosure of which is incorporated herein by reference. Accelerators or reducing agents such as oxygen scavengers and active hydrogen donors acting as chain transfer agents are useful additions to compositions to improve photospeed. Oxygen scavengers that have been found to be useful are phosphines, phosphonates, phosphites, stannous salts and other compounds that are easily oxidized by oxygen. Useful chain transfer agents are N-phenyl glycine, trimethylbarbituric acid, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole. and other compounds that have hydrogens that are readily abstractable by radicals. A wide range of nonpolymerizable plasticizers are effective in achieving improved exposure and development temperature latitude. Selection of a suitable plasticizer is determined by compatibility with other components of the photopolymerizable composition, particularly the binder. monomer and other components. With acrylic binders. for example, dibutyl phthalate and other esters of aromatic acids; esters of aliphatic polyacids such as diisooctyl adipate, nitrate esters, etc.; aromatic or aliphatic acid esters of glycols, polyoxyalkylene glycols. aliphatic polyols, etc.: alkyl and aryl phosphates; low molecular weight polyester of poly-a-methylstyrenes; chlorinated paraffins; and sulfonamide types may be used. In general, water insoluble plasticizers are preferred for greater high humidity storage stability, but are not necessary to get improved latitude. Other inert additives such as dyes, pigments and fillers are known to those skilled in the art. These additives are generally present in minor amounts and should not interfere with the exposure of the photopolymerizable layer. The photopolymerizable compositions described herein may be coated on a wide variety of substrates. By substrate is meant any natural or synthetic support. preferably one which is capable of existing in a flexible or rigid film or sheet form. For example, the substrate could be a metal sheet or foil. a sheet or film of synthetic organic resin, cellulose paper, fiberboard. and the like, or a composite of two or more of these materials. Specific substrates include alumina-blasted aluminum, anodized aluminum, alumina-blasted polyethylene terephthalate film, polyethylene terephthalate film, e.g.. resin-subbed polyethylene terephthalate film, flame or electrostatic discharge treated polyethylene terephthalate film, polyvinyl alcohol-coated paper, crosslinked polyester-coated paper, nylon, glass, cellulose acetate film, heavy paper such as lithographic paper, and the like. The particular substrate will generally be determined by the use application involved. For example, when printed circuits are produced, the substrate may be a plate which is a copper coating on fiberboard. Preferably the layer of the photopolymerizable compositions have a thickness ranging from about 0.0001 inch (-0.0003 cm) to about 0.01 inch (0.025 cm) and are adhered with low to moderate adherence to a thin, flexible, polymeric film support which may transmit radiation actinic to the photopolymerizable layer. The opposite side of the photopolymerizable layer may have adhered thereto a protective cover layer or cover sheet wherein the sheet has less adherence to the layer than the adherence between the film support and the layer. Preferred supports are a transparent polyethylene terephthalate film having a thickness of about 0.001 inch (-0.0025 cm) and a copper support. Polyethylene, 0.001 inch (-0.0025 cm) is a preferred cover sheet; polyvinyl alcohol coating is a preferred cover layer. Any convenient source of actinic radiation providing wavelengths in the region of the spectrum that overlap the absorption bands of the ketone compounds can be used to activate the photopolymerizable compositions for radical formation, image formation and photopolymerization initiation. The light can be natural or artificial, monochromatic or polychromatic, incoherent or coherent, and for high efficiency should correspond closely in wavelengths to the sensitizer's principal absorption bands and should be sufficiently intense to activate a substantial proportion of the ketone compound. Conventional light sources include fluorescent lamps, mercury, metal additive, pulsed xenon. and arc lamps providing narrow or broad light bands centered near 405, 436 and 546 nm (Hg) wavelengths. Coherent light sources are the pulsed xenon chloride, argon ion, and ionized neon-lasers. Visible emitting cathode ray tubes widely useful in printout systems for writing on photosensitive materials are also useful with the subject compositions. These in general involve an ultraviolet or visible-emitting phosphor internal coating as the means for converting electrical energy to light energy and a fiber optic face plate as the means for directing the radiation to the photosensitive target. A preferred mode is illustrated in Example 2 wherein bis-(N-ethyl-l,213,4-tetrahydro-6#quinolyl) ketone is used in conjunction with a hexaarylbiimidazole photoinitiator. INDUSTRIAL APPLICABILITY The photopolymerizable compositions of this invention are useful in photoresists in making printed circuits or in chemical milling, and as soldermasks. The increased speed of the compositions is particularly useful in projection speed photoresists. The increase in speed results in a saving of energy and related costs since lower energy exposure sources can be used or more elements can be exposed and developed in a given amount of time. Alternatively, the photopolymerizable element can be exposed by means of an exposure source maintained at a greater distance than normal for known sensitized elements. The photopolymerizable compositions are also useful in printing plates for offset and letterpress. engineering drafting films, toning films, etc. EXAMPLES The invention is illustrated by the following examples wherein the parts and percentages are by weight. The molecular weights of polymeric compounds are weight average molecular weights (Mw). The Mw of the polymers can be determined by using a light scattering technique using known standard samples, e.g., polystyrene, polymethacrylic acid. polymethylmethacrylate, etc. as known to those skilled in the art. Compounds used in the examples are prepared as follows: 1. Bis(6-iulolidYl ketone) A. Preparation of dijulolidyl'methane (Reference: C. Barker. G. Hallas J. Chem. Soc. (B), 1068 (1969)) A solution of 10 g of julolidine (Aldrich Chemical Co., Milwaukee. Wisconsin) in 29 ml of distilled water was stirred at room temperature as hydrochloric acid (conc.) was added dropwise until a pH of 4 was obtained. Two ml of 40% formalin was added and the solution was heated to reflux for 6 hours, cooled to room temperature and stirred overnight. The mixture was made basic with concentrated ammonium hydroxide, the supernatant liquid poured off the gummy solid and the residue stirred with 2B alcohol until crystallization occurred. The solid was collected by filtration and recrystallized from acetone to give 5.59 g of brown needles, mp 114-1190C. The yield was 54%. B. Preparation of bis(iulolidyl ketone) In a 250 ml one neck RB flask containing 100 ml absolute ethanol was added with stirring 3.77 g dijulolidyl methane, prepared as described in A, and 5.23 g chloranil. The dark green mixture was refluxed for 1 hour, and the ethanol was removed by rotary evaporating the mixture to near dryness. Sodium hydroxide (5% solution) was added until the mixture was basic and 500 g methylene chloride was added. The layers were separated and the methylene chloride layer was dried with S g anhydrous magnesium sulfate with stirring. The filtered solution was concentrated to 50 cc and eluted through neutral Woelm Alumina. A middle fraction from elution with methylene chloride. after rotary evaporation to dryness gave 0.6 g of yellow crystals. mp 243-245 C. Other fractions totalled 1.2 g, mp 241-243 C. The total yield was 46%. An ultraviolet spectrum in ethanol gave wavelength of maximum absorption (\may) ) of 390 nm. and the molar extinction coefficient (S) was 51,400. 2. Bis-(N-ethyl-l,2.3.4-tetrahydro-6 quinolyl) ketone A. Preparation of bis-(n-ethyl-1,2,3,4- tetrahydro-6-guinolyl )methane To 52 ml of distilled water with stirring was added 16.60 g (0.013 mole) N-ethyl tetrahydroquinoline. followed by the slow addition of 10.5 g of concentrated hydrochloric acid. The solution (pH 3-4) was stirred as 3.6 ml of 38% formalin solution was added, heated to reflux for 7 hours and stirred at room temperature overnight. The mixture was made basic with concentrated ammonium hydroxide and the product extracted with methylene chloride. This solution was dried with anhydrous magnesium sulfate, filtered and was rotary evaporated to dryness to yield 17.14 g of an oil (99.5% yield). Crystallization occurred on stirring with ethanol. mp 61-650C. B. Preparation of bis-(N-ethyl-l.2.3.4- tetrahydro-6-guinolyl) ketone To 400 ml absolute ethanol was added with stirring 16 g (0.0478 mole) bis-(N-ethyl-l,2.3.4- tetrahydro-6-quinolyl)methane. prepared as described in A. and 23.82 g chloranil. The green mixture was heated to reflux for 1 hour. cooled to room temperature over 1 hour and rotary evaporated to dryness. The residue was taken up in methylene chloride and eluted through neutral Woelm Alumina. A red solid remained on the top of the column. The fractions were rotary evaporated to dryness and the oil taken up in ethanol to yield light yellow crystals which were collected by filtration to give 6.06 g, mp 120-120.50C (36.4% yield). An ultraviolet spectrum in ethanol gave a Xmax of 382 nm, z was 40.500. 3. p-Methoxyphenyl-(N-ethyl-1,2,3,4- tetrahydro-6-quinolyl ) ketone A mixture of 27.4 g of ethyl tetrahydroquinoline. 11.4 g of p-methoxyphenyl benzamide and 10.4 g of phosphorous -oxychloride was heated at 1000C under nitrogen with stirring until the reaction temperature reached 1600C and a viscous mixture resulted. The stirring was stopped and heating at 1000C was continued for 3 hours. A solution of 6.5 ml conc. hydrochloric acid diluted to 50 ml was added, the mixture heated to 1000C and the solution filtered into 200 ml of water. The resultant oil was extracted with methylene chloride. The product was concentrated to 22.5 g, transferred to a Kugelrohr and distilled to give a red oil at 2000C at 0.2 mm to yield 10.1 g. 4. 2,7 Bis-N,N-dimethylaminofluorenone 4.5 g Pyronin Y (Aldrich Chemical Co. Milwaukee, Wisconsin) was dissolved in 500 ml water and 10 ml 50% aqueous sodium hydroxide was added with stirring. The mixture was filtered and the solid washed with water. The solid was dissolved in conc. sulfuric acid, stirred at room temperature for 1.5 hours and poured onto 5 1 of water. The solution was shaken 2X with 500 ml of ether, the ether layer dried with anhydrous magnesium sulfate and rotary evaporated to dryness. The solid was taken up in hot ethanol and the solution cooled to yield 0.4 g of a crystalline solid, m.p. 240-242 C. 5. 2,7-Bis-N,N-dimethylamino-9,9-dimethyl 10-anthrone A. Preparation of Methyl-m-N,N-dimethyl aminobenzoate A mixture of 2.5 ml concentrated hydrochloric acid, 300 ml methanol, 0.1 g 5% palladium on charcoal and 10 g of methyl m-nitrobenzoate was combined with 8.3 ml of a 40% formalin solution at 5 C. The mixture was hydrogenated at a hydrogen pressure of from 48 to 25 2. psi (3.37 to 1.76 kg/om ) in a period of one hour. The mixture was filtered, the methanol evaporated off with a rotary evaporator and 100 ml of water was added. Potassium carbonate was added until a pH of 8-9 was obtained. The product was extracted with 100 ml of ether, the ether layer dried with anhydrous magnesium sulfate and the ether was removed by rotary evaporation to yield 9.17 g. The preparation was repeated on a 5X scale and the crude products were combined. The combined products were shaken with 10 ml acetic anhydride, 10 ml pyridine and 100 ml water and the product extracted 2 times with 100 ml ether. The ether layer was dried over anhydrous magnesium sulfate, filtered, rotary evaporated to an oil that was vacuum distilled to yield 35.31 g, b.p. 1040C at 0.65 mm. B. Preparation of 2-m-N,N-dimethylamino phenylpropan-2-ol Methyl iodide 88.7 g was added to 14.52 g of magnesium turnings in 200 ml of dry ether to prepare methyl magnesium iodide, 25 g methyl-m-N,N-dimethyl- aminobenzoate was added with stirring. the mixture was refluxed for 1 hour. cooled to room temperature and 100 ml of 10% aqueous ammonium chloride solution was added. The ether layer was dried over magnesium sulfate and concentrated to 24.3 g of an oil product. C. Preparation of 2-m-N,N-dimethylamino phenylpropene Ten grams of 2-m-N,N-dimethylaminophenyl propan-2-ol was combined with 10 g of freshly fused and crushed potassium hydrogen sulfate and 0.1 g of p-methoxyphenol. The mixture was heated to 1500C for 2 hours, cooled, poured into 100 ml water containing 10 g of sodium hydroxide. The product was extracted 2 times with 50 ml ether. the extract dried over magnesium sulfate, concentrated and the oil vacuum distilled to yield 4.6 g of a colorless oil b.p. 63-650C at 0.1 mm. D. Preparation of bis-p-N.N-dimethylamino phenyl-2-isopropenyl-4-N,N,-dimethyl aminophenylmethane A mixture of 6.44 g of Michler's hydrol, 4.6 g 2-m-N,N-dimethylaminophenylpropene and 52 ml of 2N hydrochloric acid was refluxed 12 hours, cooled to room temperature. and poured into 1 1 of 1N sodium hydroxide with rapid stirring to yield 10.1 g of light blue solid after filtration and drying. E. Preparation of 2.7-bis(p-N,N-dimethyl amino)-9 , 9-dimethyl-10-p-N,N-dimethyl aminophenyl-9.10-dihydroanthracene Ten and one tenth grams of bis-p-N,N-dimethylaminophenyl-2-isopropenyl-4-N,N- dimethylaminophenylmethane was added to 100 ml of concentrated sulfuric acid. This was kept at room temperature for 24 hours and poured into ammonium hydroxide with rapid stirring to yield a light blue solid which was washed 3 times with 100 ml of water and air dried to yield 9.5 g of product. F. Preparation of 2,7-bis(p-N,N-dimethyl amino)-9.9-dimethyl-l0-p-N.N-dimethyl aminophenyl-9,lQ-dihydro-10-anthranilium chloride To 5.62 g lead nitrate pentahydrate dissolved in 50 ml water was added 90 ml of Cloroxe bleach. The mixture was boiled for 15 minutes, cooled to room temperature and the supernatant decanted off from the lead oxide. The solid was washed 3 times with 100 ml of water. A solution of 7.04 g of 2,7-bis(p-N.N-dimethylamino)-9,9-dimethyl- l0-p-N,N-dimethylaminophenyl-9, lO-dihydroanthracene in 200 ml water containing 8.5 ml concentrated hydrochloric acid and 45 g of crushed ice was added to the lead oxide slurry. The dark blue mixture was stirred 2 hours and a solution of 19.3 g of sodium sulfate in 20 ml water was added. The mixture was filtered, 2.9 g sodium acetate and 65 g sodium chloride added to the filtrate and the mixture filtered 12 hours later to yield 6.5 g of a blue solid after drying. G. Preparation of 2,7-bis-N,N-dimethylamino 9, 9-dimethyl-lO-anthrone Six and one-half grams of 2.7-bis(p-N.N-di- methylamino)-9,9-dimethyl-10-p-N,N-dimethylaminophenyl 9.10-dihydro-10-anthranilium chloride was dissolved in 500 ml ethanol. Eighteen and two-tenths ml of 1N sodium hydroxide solution was added followed by 300 ml of 30% hydrogen peroxide. A green solid was collected by filtration, was air dried, dissolved in ether and chromatographed on alumina prep plates to yield 0.1 g of a light yellow solid which was rechromatographed two more times to yield 0.05 g of a yellow solid with m.p. of 204-2060C. Literature m.p. of 207-2080C was reported by C. Aaron. C. Baker. J. Chem. Soc.. 2655 (1963). EXAMPLES 1 to 3 The following photosensitive compositions were prepared: Amount (g) Ingredient 1 2 3 Bis(6-julolidyl)ketone 0.0146 - Bis-(N-ethyl-1.2.3,4- - 0.0146 0.0759 tetrahydro-6-quinolyl) ketone Tetraethyleneglycol 0.2264 0.2264 0.2.264 dimethacrylate Bis(2-o-chlorophenyl-4,5- 0.1298 0.1298 0.1298 diphenyl)imidazole Copolymer of styrene/maleic 0.5539 0.6539 0.5539 anhydride (1.4/1) partially esterified with isobutanol mixture, acid No. 190, mol. wt. ca. 10,000 Terpolymer of ethyl 0.5327 0.5327 0.5327 acrylate (56.6), methyl methacrylate (37.6). acrylic acid (7.0), acid no. 76-85; mol. wt. ca. 100.000 Methylene chloride 7.95 7.95 7.95 Methanol 0.6 0.6 0.6 Each composition was coated on the resin subbed side of a 0.004 inch (0.01 cm) polyethylene terephthalate film support using a 0.002 inch (0.005 cm) doctor knife, the resultant film air dried and a 0.001 inch (0.0025 cm) polyethylene terephthalate dover sheet laminated over the coating at 1800F (820C) and at 4 ft/min (121.9 cm/min). A stepwedge target was placed over the film which was then contacted in a vacuum frame. An exposure was made with a 2000 watt mercury photopolymer Addalux lamp at a distance of 38 inches (96.5 cm) using an Assore Light Integrator Platemaker Model 1415-12 with a Berkey Ascor#l60l-40 light source. The films were exposed 5 units and after a two minute hold time the cover sheets were removed and the films were developed for 6 seconds at 220C in a solution of 84 g of potassium carbonate 1.5 hydrate, 5 g potassium hydrogen carbonate and 1536 g distilled water followed by 40 psi (2.81 kg/sq cm) 320C spray water rinsing. The number of < steps of polymeric image are shown in Table I. TABLE I Example % Compound < Stepwedqe Response 1 1 21 2 1 25 3 5 22 EXAMPLE 4 The following photosensitive composition was prepared: Ingredient Amount (q) 4-Trichloromethyl-4-methyl-2,5- 0.1284 cyclohexadienone Compound described in Example 1 0.0223 Tetraethyleneglycol dimethacrylate 0.2293 Terpolymer described in Examples 1-3 0.5396 Copolymer of styrene/maleic anhydride 0.5610 described in Examples 1-3 Methylene chloride 8.06 Methanol 0.61 This solution was coated, laminated. exposed for five units and developed for 6 seconds as described in Examples 1-3 to yield 5 < steps of polymeric image. EXAMPLE 5 The following photosensitive compositions were prepared: Amount (g) Example Ingredient 5 Control Compound described in Example 2 0.0134 Bis(2-o-chlorophenyl-4,5-diphenyl) - 0.87 imidazole Tetraethyleneglycol dimethacrylate 0.2294 1.79 Terpolymer described in 0.5398 3.56 Examples 1-3 Copolymer of styrene/maleic 0.5612 3.78 anhydride described in Examples 1-3 Methylene chloride 7.95 52.87 Methanol 0.6 4.01 These solutions were coated and the films laminated, exposed and developed for 6 seconds as described in Examples 1-3. The results of the exposures are: Exposure developed Example (units) ##2 Stepwedqe Response 5 50 12 Control 200 15 EXAMPLES 6-8 The following photosensitive compositions were prepared: Amount (g) Ingredient 6 Control 7 Control Compound described 0.0142 - 0.0142 in Example 2 Benzophenone 0.0707 0.0700 - Benzoin methyl - - 0.0707 0.0700 ether 9-Xanthenone Tetraethylene- 0.2294 0.2294 0.2294 0.2294 glycol dimeth acrylate Terpolymer 0.5398 0.5398 0.5398 0.5398 described in Examples 1-3 Copolymer of 0.5612 0.5612 0.5612 0.5612 styrenefmaleic anhydride described in Examples 1-3 Methylene 8.06 8.06 8.06 8.06 chloride Methanol 0.61 0.61 0.61 0.61 Amount (q) Ingredient 8 Control Compound described 0.0142 in Example 2 Benzophenone - - Benzoin methyl ether - - 9-Xanthenone 0.0707 0.0700 Tetraethylene- 0.2294 0.2294 glycol dimeth acrylate Terpolymer 0.5398 0.5398 described in Examples 1-3 Copolymer of 0.5612 0.5612 styrene/maleic anhydride described in Examples 1-3 Methylene 8.06 8.06 chloride Methanol 0.61 0.61 These solutions were coated and the films laminated, exposed and developed for 6 seconds as described in Examples 1-3. The results of the exposures are: Exposure Example (units) 2Stepwedge Response 6 50 13 Control 500 2 7 50 14 Control 200 9 8 50 13 Control 500 4 EXAMPLE 9 A photosensitive composition was prepared: Ingredient Amount (q) Trimethylolpropane triacrylate 150.82 Copolymer described in Examples 1-3 167.47 Terpolymer of methylmethacrylate(71)/ 111.64 ethyl acrylate(17)/acrylic acid(12), Mw 150,000 Terpolymer of methylmethacrylate(55)/ 82.33 ethyl acrylate(35)/acrylic acid(10); Mw 50,000 Benzophenone 28.5 Bis(2-o-chlorophenyl-4,5-diphenyl) 11.4 imidazole Bis(2,4-di-o-chlorophenyl-5- 11.4 (3',4'-dimethoxyphenyl)-imidazole Benzotriazole 2.28 VictoriaR green dye. C.I. Basic Green 4 0.285 Tri(p-N,N-dimethylaminophenyl)methane 1.14 1,4, 4-Trimethyl-2, 3-diazobicyclo [ 3 .2.21 0.171 non-2-ene-N,N -dioxide p-Toluene sulfonic acid 0.57 Compound described in Example 2 2.85 Methanol 89.7 Methylene chloride 1045.0 This solution was extrusion die coated on 0.001 inch (0.0025 cm) polyethylene terephthalate film to a thickness of 0.0013 inch and a 0.001 inch polyethylene cover sheet laminated to it. After removal of the cover sheet the dry coating was laminated to freshly scrubbed copper surfaced epoxy boards at 2400F (116 C), 2 feet/minute (0.61 m/minute), 40 psi (2.81 kg/sq cm). The laminated boards were exposed with the light source described in Examples 1-3 for 9 units through a 7 T stepwedge to yield after development 14##2 stepwedge steps of polymer. The development was in a Ristono processor (E. I. du Pont de Nemours and Company, Wilmington, Delaware) containing a 1% solution of sodium carbonate in tap water (pH about 10.4) at 1050F (41 C). EXAMPLES 10 and 11 The compositions of Examples 10 and 11 were prepared and coated with a 0.010 inch (0.25 mm) doctor knife on 0.001 inch (0.0025 cm) polyethylene terephthalate film with the film moving under the knife at 6 ft (183 cm)/min and dried at 1200F ( 490C) for 2 minutes in a forced air dryer before lamination of a polyethylene cover sheet at l60 F (71 C) 40 psi (2.8 kg/cmê), 183 cm/min. The films were laminated to freshly scrubbed copper surfaced epoxy boards at 2400F (1150C), 2 ft (61 cm)/min, 40 psi (2.8 2 kg/cm ). The laminated boards were exposed with a 2.5 kw Hg xenon lamp with a 500-mm Bausch and Lomb monochromator set at 365 nm. The irradiance level was determined with a YSI Model 65 radiometer. Amount (g) Ingredient 10 11 Polyoxyethylated trimethylol 2.3122 2.3122 propane triacrylate Victoria Green C.I. Basic 0.0062 0.0062 Green 4 Copolymer of 50/50 styrene/ 4.8049 4.8049 maleic anhydride esterified with isobutanol mixture; Mw 20,000; Tg is 2100C Terpolymer described in 4.8049 4.8049 Examples 1-3 l,4,4-Trimethyl-2,3- 0.0008 0.0008 diazabicycloC3.2.2lnon- 2-ene-N,N1 -dioxide Benzotriazole 0.0616 0.0616 Sodium bis-dioctylsulfo- 0.6166 0.6166 succinate 2-Mercaptobenzoxazole 0.0925 0.0925 Trimethylolpropane triacrylate 1.5824 1.5824 Block copolymer of ethylene 0.4624 0.4624 glycol and propylene glycol; ; Mw is 3,200 Tris(p-N,N-dimethylamino- 0.0385 0.0385 phenyl )methane Bis(2-o-chlorophenyl-4,5- 0.5880 0.5880 diphenyl)imidazole Compound described in Ex. 3 0.0154 Compound described in Ex. 4 - 0.0154 Methylene chloride 37.2 37.2 Methanol 2.4 2.4 Example mJ/cmê for 12##2 Steps of Polymer 10 23 11 23 EXAMPLES 12 to 16 Nonpigmented aqueous washout films were prepared -according to the procedure given for Examples 1-3 except that the the coatings were prepared with the doctor knife held rigid as the film base was passed underneath at 6 ft (183 cm)/minute. The coated films passed through a 1200F (-490C) forced air dryer with a contact time of 2 minutes and were laminated at 180-1950F (82-900C), 40 psi (2.8 kg/cm2) at 6 ft (183 cm)/minute. The compositions and film responses are: TABLE II Ingredient 12 Control Tetraethyleneglycol 0.2264 0.2264 dimethacrylate Terpolymer of 0.5327 0.5327 Examples 1-3 Styrene, maleic anhydride 0.5539 0.5539 copolymer of Ex. 1-3 Bis(2-o-chlorophenyl- 0.1298 0.1298 4, 5-diphenyl) imidazole Bis-(N-ethyl-l,2.3,4- 0.0129 tetrahydro-6-quinolyl) ketone 2-Mercaptobenzothiazole N-phenyl glycine Stannous chloride dihydrate Triphenyl phosphine Methylene chloride 7.95 7.95 Methanol 0.61 0.61 Units exposure 5 50 steps of polymeric 11 15 image Relative photospeed 4.0 1.0 TABLE II (continued) Ingredient 13 Control Tetraethyleneglycol 0.2264 0.2264 dimethacrylate Terpolymer of 0.5327 0.5327 Examples 1-3 Styrene, maleic anhydride 0.#5539 0.5539 copolymer of Ex. 1-3 Bis(2-o-chlorophenyl- 0.1298 0.1298 4, 5-diphenyl) imidazole Bis-(N-ethyl-l,2,3,4- 0.0129 tetrahydro-6-quinolyl) ketone 2-Mercaptobenzothiazole 0.0073 0.0073 N-phenyl glycine Stannous chloride dihydrate Triphenyl phosphine Methylene chloride 7.95 7.95 Methanol 0.61 0.61 Units exposure 5 30 steps of polymeric 12 15 image Relative photospeed 5.0 1.7 TABLE II (continued) Ingredient 14 Control Tetraethyleneglycol 0.2264 0.2264 dimethacrylate Terpolymer of 0.5327 0.5327 Examples 1-3 Styrene, maleic anhydride 0.5539 0.5539 copolymer of Ex. 1-3 Bis(2-o-chlorophenyl- 0.1298 0.1298 4, 5-diphenyl) imidazole Bis-(N-ethyl-l,2,3,4- 0.0129 tetrahydro-6-quinolyl) ketone 2-Mercaptobenzothiazole N-phenyl glycine 0.0073 0.0073 Stannous chloride dihydrate Triphenyl phosphine Methylene chloride 7.95 7.95 Methanol 0.61 0.61 Units exposure 5 30 steps of polymeric 13 17 image Relative photospeed 6.3 2.6 TABLE II (continued) Ingredient 15 Control Tetraethyleneglycol 0.2264 0.2264 dimethacrylate Terpolymer of 0.5327 0.5327 Examples 1-3 Styrene, maleic anhydride 0.5539 0.5539 copolymer of Ex. 1-3 Bis(2-o-chlorophenyl- 0.1298 0.1298 4,5-diphenyl)imidazole Bis-(N-ethyl-152,3,4- 0.0129 tetrahydro-6-quinolyl) ketone 2-Mercaptobenzothiazole N-phenyl glycine Stannous chloride 0.0297 0.0297 dihydrate Triphenyl phosphine Methylene chloride 7.95 7.95 Methanol 0.61 0.61 Units exposure 10 30 #,M#2steps of polymeric 19 22 image Relative photospeed 12.7 8.4 TABLE II (continued) Ingredient 16 Control Tetraethyleneglycol 0.2264 0.2264 dimethacrylate Terpolymer of 0.5327 0.5327 Examples 1-3 Styrene, maleic anhydride 0.5539 0.5539 copolymer of Ex. 1-3 Bis(2-o-chlorophenyl- 0.1298 0.1298 4,5-diphenyllimidazole Bis-(N-ethyl-l,2,3,4- 0.0129 tetrahydro-6-quinolyl) ketone 2-Mercaptobenzothiazole N-phenyl glycine Stannous chloride dihydrate Triphenyl phosphine 0.0297 0.0297 Methylene chloride 7.95 7.95 Methanol 0.61 0.61 Units exposure 2 30 + steps of polymeric 12 21 image Relative photospeed 12.5 6.7 EXAMPLES 17 to 18 The following photosensitive compositions were prepared: Ingredient 17 18 Control Bis(2-o-chlorophenyl-4,5- 0.6129 0.2043 0.6129 diphenyl)imadazole Trimethylolpropanetri- 2.7579 0.9193 2.7579 methacrylate Polyoxyethylated tri- 0.6129 0.2043 0.6129 methylolpropanetri acrylate Poylmethylmethacrylate, 1.3023 0.4341 1.3023 Mw 200,000; Tg 105 C Polyvinylacetate. Mw 1.3023 0.4341 1.3023 901000. Air Products and Chemicals, Inc. Allentown, Pa. Polyoxyethylene lauryl 0.6129 0.2043 0.6129 ether 2-Mercaptobenzoxazole 0.2298 0.0766 0.2298 Compound described in 0.2298 - Example 2 Compound described in - 0.0766 Example 5 Methylene chloride 22.569 7.523 22.569 Each composition was coated on 0.001 inch (0.0025 cm) polyethylene terephthalate film support using a 0.002 inch (0.005 cm) doctor knife, the resultant film was air dried and a 0.001 inch (0.0025 cm) polyethylené cover sheet laminated at 1500F (65.60C) at 3 ft (0.91 m)/min. The cover sheets were delaminated and the film laminated at room temperature at 3 ft/min (0.91 m/min) onto Krome-Kote@ paper. The laminates were exposed through stepwedge targets with the same source used for Examples 1-3. After a two-minute hold time after exposure the polyethylene terephthalate was delaminated and the image toned with CROMALINe toner. The number of #2 steps that were tackfree, accepting no toner, are: Example # of of #2 Steps Not Toned 17 7 18 6 Control 3

Claims: CLAIMS 1. A photopolymerizable composition comprising an admixture of (a) at least one nongaseous ethylenically unsaturated compound having at least one terminal ethylenically unsaturated group, a boiling point above 100 C at normal atmospheric pressure and being capable of addition polymerization, (b) at least one organic polymeric binder compound, (c) optionally at least one photoinitiator or photoinitiator system, the improvement wherein the composition contains (d) 0.001 to 15% by weight of the total composition of at least one constrained N-alkylamino aryl ketone of the formula: : EMI37.1 wherein R1 and R5 are H, R2 is lower alkyl of 1 to 4 carbon atoms, R3 is lower alkyl of 1 to 4 carbon atoms, R4 and R7 are H, R6 is H, OCH3 or N-R8 , R is lower R9 alkyl of 1 to 4 carbon atoms, R9 is lower alkyl of 1 to 4 carbon atoms, R1 and R2 taken together is -CH2CH2CH2-, R3 and R4 taken together is -CH2CH2CH2-, R5 and R8 taken together is -CH2CH2CH2 -, R7 and R9 taken together is -CH2CH2CH2- and Z is H-, H- or a bridge between#the two aromatic rings taken from the group of EMI37.2 -O-, -S-, with the-proviso that when Z is H-, H- at least one of R1 and R2, R3 and R4, R5 and R8 and R7 and R9 when taken together is -CH2CH2CH2-. 2. A photopolymerizable composition according to claim 1 which contains 0.001 to 20 parts by-weight per 100 parts by weight of the combined weight of ethylenically unsaturated compound and binder at least one photoinitiator taken from the group consisting of hexaarylbiimidazoles, 4-trichloromethyl-4-methyl-2,5cyclohexadienones, quinones, alkylaryl ketones, benzophenones, and mixtures thereof. 3. A photopolymerizable composition according to claim 2 wherein the photoinitiator is a hexaarylbiimidazole compound. 4. A photopolymerizable composition according to claim 1 wherein the ethylenically unsaturated compound and organic polymeric binder are present in relative amounts of 3 to 97 and 97 to 3 parts by weight, respectively. 5. A photopolymerizable composition according to claim 1 wherein the ketone compound is bis(6-julolidyl ketone). 6. A photopolymerizable composition according to claim 1 wherein the ketone compound is bis- (N-ethyl-l,2 '3, 4-tetrahydro-6-quinolyl)ketone. 7. A photopolymerizable composition according to claim 5 wherein the ethylenically unsaturated compound is tetraethyleneglycol diemthacrylate. 8. A photopolymerizable composition according to claim 6 wherein the ethylenically unsaturated compound is tetraethyleneglycol dimethacrylate. 9. A photopolymerizable element comprising a support bearing a layer of a composition according to claim 1. 10. A photopolymerizable element according to claim 9 wherein the support is copper.

Inventors: ANDERSON, ALBERT GORDON, DR., DUEBER, THOMAS EUGENE
Applicants: E.I. DU PONT DE NEMOURS AND COMPANY
Application year: 1984
Main classification: C08F2
IPC codes: G03F7, C08F2, G03C1