CA1113638A

CA1113638A - Photopolymerizable composition containing a sensitized aromatic iodonium or sulfonium compound

Info

Publication number: CA1113638A
Application number: CA349,909A
Authority: CA
Inventors: George H. Smith
Original assignee: Minnesota Mining and Manufacturing Co
Current assignee: 3M Co
Priority date: 1979-05-21
Filing date: 1980-04-15
Publication date: 1981-12-01
Also published as: GB2053243A; KR840000122B1; JPS612081B2; DE3019211A1; SE446780B; US4250053A; FR2457511A1; GB2053243B; ES8106967A1; ZA802991B; JPS55155018A; FR2457511B1; AU5855980A; BE883404A; ES491604A0; KR830002827A; SE8003647L; IT1133014B; IT8048736A0; AU521591B2

Abstract

Abstract of the Disclosure Iodonium and sulfonium photoinitiators are naturally sensitive to only a small portion of the electromagnetic spectrum, particularly in the ultraviolet region.
It would be desirable to extend the sensitivity of the photoinitiators to the visible region of the spectrum to enable more extensive use of the photoinitiators.
Various classes of spectral sensitizing dyes for iodonium and sulfonium salts are disclosed herein.

Description

40,645-CAN/MAL
3~

PHOTOPOLYMERIZABLE COMPOSITION CON~AINING
A SENSITI2ED ~ROMATIC IODONIUM OR SWI,~ONIUM COMPOUND

This invention relates to iodonium and sulfonium compounds and, more particularly, to photosensitization of aromatic iodonium and sulfonium photoinitiators.
Iodonium and sulfonium salts are known to absorb S ultraviolet light only at wavelengths below about 300 nm, and their absorption spectra are essentially independent of the anion portion of the moleculeO This limited spectral response is accordingly a serious inherent limitation with respect to their use a~ photoinitiators in photosensitive compositions. For example, in the field of graphic arts, such as in the preparation of printing plates, a photographic film negative is disposed between the lamp and the photosensitive plate. This film negative prevent~ the transmission of appreciable light of wavelengths below about 340 nm. Furthermore, when photosensitive compositions are used as photocurable coatings, light of wavelengths below about 300 nm decreases in intensity as it passes through the coating, due to absorption of the light by the monomeric compounds, pigments, binders, etc., present in the coating. Either occurrence would reduce the usefulness of sulfonium and iodonium photoinitiators because o~ their limited spectral ; response.
Although there are dozens of known classes of dyes and other materials which can be used to broaden the spectral response of photosensitive compositions, it has not been possible to predict which materials would be useful in sensitizing aromatic iodonium and sulfonium salts. In fact, it has been found that only select materials are useful in sensitizing these aromatic salts.
For example, a well known and widely used class of energy transfer sensitizers, known as triplet sensitizers, e.g., benzophenone, acetophenone, etc,, are not significantly effective for sensitizing aromatic sulfonium and iodonium salts. U.S. Patent No. 4,069,054 discloses certain a~ines ,'' ' ' ~ .
''"'~ ': ' . . - - .

~;'' ' '' . ' 3~3 and heterocyclic compounds which are useful sensitizers for sulfonium photoinitiators. U.S. Patent No. 4,026,705 also discloses sellsitiæers for iodonium photoinitiators.

In accordance with the present invention there is provided a photosensitive admix~ure comprising an aromatic lodonium or sulfoniu]n compound and a sensitizing compound selected from the class of polyarylenes, polyarylpolyenes, 2,5-diphenylisobenzofurans,

2,5-diarylcyclopentadiene~, diarylfurans, diarylthiofurans, diarylpyrro:Ls, polyarylphenylenes, coumarins, and polyaryl~2-pyrazolines.
There are many advantages associated with sensitized aromatic sulfonium compounds. For example, in photosensitive compositions the speed of light curiny is increased, and safer and less expensive exposure lamps may be used effectively.

Aromatic sulfonium comounds which can be sensitized in accordance with this invention include those having the formulae:
Zn ~ S X or 1 ~ +~ 3_ wherein Rl, R2, and R3 can be the same or dif~erent provided that at least one vf such groups i5 aromatic. Such groups can be selected from aromatic groups having 4 to 20 carbon atoms (e.y., substituted or unsubstituted phenyl, naphthyl, thienyl, and furanyl. Substitution may be with such ; groups as alkoxy, alkylthio, arylthio, halogens, etc., and alkyl radicals having 1 to 20 carbon atoms.
The term "alkyl" as used here is meant to include substituted alkyl radicals (for example, with substituents such as haloyen, hydroxy, alkoxy, aryl).
Preferably, Rl, R2 and R3 are each aromatic. 2 is ' ` ~. , selected fro1ll the group consisting o-E oxygen; sulfur; S=o; C=O; O=S=O;
R-N-, where l~ is aryl (of ~ to 20 carbons, such as ~phenyl~ or acyl (of 2 to 20 carbons, such as acetyl, benzoyl, etc.); a carbon-to-carbon bond; or where R~ and R5 are selected from the group consisting o-E hydro-gen, an alkyl radical having 1 to 4 carbon atoms, and an alkenyl radical having 2 to 4 carbon atoms; and n is zero or 1; and X is any anion.
Although, the particular nature of the anion, X, is not limiting or critical for the purposes of this invention ~i.e., for the purposes of sensitizing the sulfonium cation), for many applications it is preferred for the aromatic sulfonium compound to be in the form of a complex salt where X is selected from tetrafluoroborate, hexafluorophosphate, hexafluoroarsen-ate, hexafluoroantimonate, and hydroxypentafluoroantimonate ~e.g., for photoinitiation of cationically polymerizable materials such as epoxy resins or epoxy resins and polyols).
Aromatic sulfonium salts are known and recognized in the art.
Triaryl-substituted sulfonium compounds, for example, can be prepared by the procedures described in C. H. Wiegand et al., "Synthesis and Reactions of Triarylsulfonium Halides", J. Org. Chem. 33, 2671-75 (1968). Aromatic sul-fonium salts also having alkyl-substitution can be prepared by the proced-ures described in ~. Okhubo et al., J. Org. Chem. 36, 3149-55 (1971). The ~; preferred method for making triaryl-substituted sulfonium compounds is de-scribed in United States Patent No. 2,807,648, from which complex sulfonium salts can be made. The complex sulfonium salts can be prepared from the corresponding simple salts, such as the bisulfate or halide salts, by meta-thesis with a metal or ammonium salt or acid of the complex anion desired.

.

i3~

The s~llfonium coml~lex ~alts are substituted ~ith at least one, ancl pre~erably thr~e, dromatic yroup~.
Representative c~ro~ps are arolnatic groups ha~ing 4 to 20 carbon atoms and are se7ecte~ ~om phenyl, thienyl and furanyl groups. These aromatic gro~ps may optionally have ; one or more fused benzo rings (e.g., naphthyl and the like; benzothienyl, dibenzothienyl; benzofuranyl, dibenzofuranyl; etc.). Such aromatic groups may also be substituted, if desired, by one or more oE the following groups, or by other groups which are ess~ntially non-reactive with other components present in the particular composition in which ~he complex salt i5 to be used: halogen, nitro, aryl, ester groups (e.g., alkoxycarbonyl such as methoxycarbonyl and ethoxycarbonyl, phenoxycarbonyl and acyloxy such as acetoxy and propionyloxy), alkoxy groups (e.~., methoxy, ethoxy, butoxy, and the like), aryl groups (e.g., phenyl), alkyl groups (e.g., methyl, ethyl, t-butyl and the like) aryloxy groups (e.g., phenoxy), alkyl-sulEonyl (e.g., methylsulfonyl, ethylsulfonyl, and the like) arylsulfonyl groups ~e.g., phenylsulfonyl groups), hydrocarbylthio groups (e.g., p-phenylthio, methylthio, etc.), perfluoroalkyl groups (e.g., trifluoromethyl, perfluoroethyl, and the like), and perfluoroalkylsulfonyl groups (e.g~, trifluoromethylsulfonyl, perfluorobutylsulEonyl, and the like).
Examples of suitable aromatic sulfonium complex salt photoinitiators include:
triphenylsulfonium tetrafluoroborate me~hyldiphenylsulfonium tetrafluoroborate dimethylphenylsulfonium hexafluorophosphate triphenylsulfonium hexafluorophosphate triphe~ylsulfonium hexafluoroantimonate diphenylnaphthylsulfonium hexafluoroarsenate tritolysulfonium hexafluorophosphate anisyldiphenylsulonium hexafluoroantimonate 4-butoxyphenyldiphenylsulfonium tetrafluoroborate `:

363~

4-chlorophenyldiphenylsulfonillm hexaEluorophosphate tr1(4-phenoxyphenyl)sul~onium hexaeluorophosphate di(4-ethoxyphenyl)methylsulfonium hexa1uoroarsenate 4-acetonylphenyldipheny.Lsulfonium tetrafluoroborate 4-thlomethoxyphenyldiphenylsulfonium hexafluorophosphate di(methoxysulfonylphenyl)methylsulEonium hexafluoroantimonat:e di(nitrophenyl)phenylsulfonium hexafluoroantimonate di~carbomethoxyphenyl)methylsul~onium hexafluorophosphate 4-acetamidophenyldiphenylsulfonium tetrafluoroborate dimethylnaphthylsulfonium hexafluorophosphate trifluoromethyldiphenylsulonium tetrafluoroborate p-~phenylthiophenyl)diphenylsulfonium hexafluoroantimonate 10-methylphenoxathiinium hexafluorophosphate 5-methylthianthrenium hexafluorophosphate ; 10-phenyl-9,9-dimethylthioxanthenium hexafluorophosphate 10-phenyl-9-oxothioxanthenium tetrafluoroborate 5-methyl-10-oxothianthrenium tetrafluoroborate 5-methyl-10,10-dioxothianthrenium hexafluorophosphate Of the aromatic sulfonium complex salts which are used in thi~ invention the preferred salts are the triaryl-substituted salts such as triphenylsulfonium ; hexafluorophosphate, p-(phenylth~o)phenyldiphenylsulfonium hexafluoroantimonate and triphenylsulfonium hexafluoroantimonate. The triaryl-substituted salts are preferred because they are more thermally stable than the mono- and diaryl suhstituted salts and accordingly may be used in one-part curable systems where long shelf life is desired. The triaryl-substituted complex salts are also more amenable to dye sensi~ization in accordance with this invention.
Aromatic iodonium salts which can be sensitized in accordance with this invention include those having the , ''"'~-' ~. ';-;

.
';:::~ . -;3~

formulae:

Ar ~ I Q Arl = I Q
wherein Arl and Ar~ are aromatic group~ having 4 to 20 carbon atoms and are preferably selected Erom phenyl, naphthyl, thieny:L, furanyl and pyrazolyl groups;
W is selected from O, S, S=O, C=OI~ O~SaO~ R6 N

where R6 is aryl of 6 to 20 carbon atoms or acyl of 2 to 20 carbon atoms (such as substituted or unsubstituted phenyl, acyl, benzoyl, etc. as described above for two sulfonium photoinitiators); a : 15 carbon to-carbon bond; or R7-¢-R8, where R7 and R8 are selected from hydrogen, alkyl groups of 1 to 4 carbon atoms, and alkenyl g~oups of 2 to 4 carbon atoms; and b is zero or l; and Q is any anion ~as described above for X ), preferably a halogen-containin~ complex anion selected fom tetrafluoroborate, hexafluorophosphate, hexafluoroarsenate, hexafluoroantimonate.
Amongst the useful iodonium salts are particularly included - diphenyliodonium iodide diphenyliodonium hexafluoroantimonate 4-chlorophenylphenyliodonium tetrafluoroborate di(4-chlorophenyl)iodonium hexafluoroantimonate diphenyliodonium hexafluorophosphate diphenyliodonium trifluoroacetate 4-trifluoromethylphenylphenyliodonium ~ tetrafluoroborate ; diphenyliodonium hexafluoroarsenate ditolyl:iodonium hexafluorophosphate di~4-methoxyphenyl)iodonium hexafluoroantimonate di(4-methoxyphenyl)iodonium chloride . -- - ~ , , ~, , , ~ , ' `, .
, ~13~;3B

(4-methylpllenyl)phenyliodonium te~rafluoroborate di-(2,4-dimethylphenyl)iodonium hexafluoroantimonate di-(4-t-butylphenyl)iodonlum hexafluoroantimonate 2,2'~diphenyliodonium hexafluorophosphate.
The amount of latent photocatalytic oniurn salt used in the photopolymerizable compositions of the invention i~ not critical but can be from about 0.01 to about 10.0~ by weight of polymerizable material and preferably 0.1 to 5% ~y weight of the total weight of polymerizable materialO The use of greater amounts oE
onium salt generally does not afford increased polymerization and the use of less tends to reduce the extent of polymerization. The compositions of the invention are prepared by mixing the onium salt with the polymerizable material until a solution i9 formed.
Because some of the onium salts may have limited solubility in the polymerizable composition, it is preferable to first dissolve the onium salt in a liquid diluent that is inert to the components of the composition and then mix this solution into the polymerizable mixture.
Suitable inert diluents include alcohols such as ethanol, ketones such as acetone, halohydrocarbons such as dichloromethane.
The compositions of the invention can be used for preparation of coatings for various substrates;
however, adhesives, sealants, binders and rubbers can also be prepared from the compositions of the invention and are particularly useful where such materials need be polymerized in situ by irradiation. The compositions of the invention can be applied to substrates by spraying, brushing, dipping, roller coating, flow coating or any of the methods used in commercial coating operations.
The compositions o the invention may contain certain additives to alter the properties of the polymerized or cured product. Thus, there may be added dyes, pigments, plasticizers, fillers and the like as long as these materials do not prevent sufficient penetration ~ .

, "

3~
. ~ 1 into the composition by radiation absorbed by the sensiti~er.
The polymerization or curing of the composition is a triggered reaction, i.e., once degradation of the photocatalytic onium salt has been initiated, the polylnerization or curing proceeds and will continue even ater terminating radiation. The use of thermal energy during or after exposure to radiation greatly accelerates polymerization or curing.
Generally speaking, the sensitized aromatic iodonium and sulfonium complex salts are significantly useful as photoinitiators Eor cationic reactions ~such as polymerization of cationlcally polymerizable monomers).
For example, the sensitized complex salts with appropriate anions are particularly suitable as photoinitiators for the polymerization or copolymerization of cationically polymerizable monomers such as epoxides (epoxy resins), epoxides and polyols, oxetanes, vinyl ethers, lactones, etc. The sensitized complex salts are also useful as photoinitiators for free-radical polymerization (e~y., polymerization of vinyl or acrylic monomers and others such as acrylate esters, acrylamide esters, acrylonitrile, styrene, butadiene, vinylidenes, etc.) and polymerizaton by hydrolysis of silanes ~as in U.S. Patent No.

4,101,513).
Generally speaking, the amount of sentitizer used in the practice of this invention is about 0.01 to 10 parts, and preferably about 0.1 to 1 part, by weight of sensitizer per part of aromatic complex salt. Factors to consider in determining the amount o sensi~izer to be included in a given composition include intended light exposure conditions, thickness of the composition to be cured, solubility of the sensiti~er in the composition, and other ~actors normally considered in the utilization of sensitizers. Of course, more than one photoinitiator and/or sensitizer may be used in a single composition.
The sensitizing compounds o the present .

~ ;
:-.
: -;

.: ;

3~;3~

invention are ~l~orescent polyaryl cornpounds selected from the group consisting o polyaryl~nes, polyarylpolyenes, 2,5-diphenyl~ isoben~ofurans, 2,5-diarylfurans, 2,5-diarylthiofuransr 2,5-diarylpyrro:Les, 2,5-diarylcyclopentadienes, polyarylphenylenes, coumarins r and polyaryl-2-pyrazolines. l'hese compounds may be partially described by the fo]lowing general formulae:
R9_Q_R10 wherein R9 and R10 are independently selected from aryl groups comprising phenyl, napthyl, biphenyl, 2~furanyl groups (all of which may be substituted or not), and Q is -~CI;CH ~ ~R )b (C - C~ II
herein Rll, R12 and ~13 are independentlY H or a phenyl group (i.e., substituted or not), and is preferably H, R is selected from -CH=CH- , -and ~

wherein R15 and R16 are H, methyl, methoxy, or phenyl when X is 0, and H or phenyl when X = S, CH2 or NR
R 7 and R ~ are H or a styryl group (i.e., substituted or not), or a stilbenyl groups (i.e., substituted or not);
X is 0, S, jH2 or NRl9 where R19 is H or phenyl;
a and c are independently 0 or 1; and b is 0, 1, 2, 3, or 4 and the sum of a~b+c is 1 to 4;

' ;
;: :
~'; ' ' 63~

--.L o--R2~~R21 IV
wherein R2 ls a 2-pyra~oline of the structure ~IC------C ~
¦ N V
HC----N

wherein R22 is a phlenyl, biphenyl group (preferable substituents being selected from lower alkyl, lower alkoxy, halogen, lower alkylamino, ; alkylsulfonyl, p-acetamido, sulEonamido, and carbalkoxy);
R23 and R24 are independently H, lower alkyl, phenyl, biphenyl, or naphthyl groups (the preferred : 15 substituents on the phenyl and naphthyl group being lower alkyl, lower alkoxy, lower alkylamino, carbalkoxy, sulfonamido and acetamido; and R21 is R20 or phenyl, biphenyl, naphthyl, or a . styryl group (substituted or not, with preferred substituents being lower alkyl, lower alkoxy, lower alkylamino, halogen and acetamido;
R
R~ ~ R26 : wherein R25 is lower alkyl or perfluoro (lower) -` : alkyl, R26 is 2-benzothiazolyl, carboalkoxy, lower acyl (1 to 5 carbon atoms), aryl (preferably phenyl), or cyano, and R25 and R2S together form a 5-membered : ring, R27 is lower alkylamino, R2~ and R29 are H or together with R 7 form a quinolizino ring Eused to the phenyl ring; and . .

' '~ : ' ~ ' ' : , . ;
.

1~ 1;3 ~

.Ll--R3~ R
R30 ~ R3

5 VII ~ R33 wherein ~30 and R31 are independently ~ or phenyl yroups, (substituted or not, e.g., with lower alkoxy), R32 and R33 are indepedently ~, phenyl, (substitutd or not, e.g., with lower alkoxy), lower alkyl, or lower alkoxy, and R34 and R35 are independently H, lower alkyl, and phenyl.
Where the term "lower" is u~ed in desribing an organic group, it means that there are no more than S
carbon atoms present in the lower group, There are a number of different classes of compounds which may be used as photosensitizers according to the practice of the present invention. These classes 2~ include, for example, the polyarylenes, the 1,3-diaryl-2-pyrazolines, the substituted coumarins, and the isobenzofurans. Examples of these compounds appear below according to their respective classes~ The examples refer to these compounds by their numbers.
A. Polyarylenes 1. p,p'-dimethoxystilbene 2. 1,4-diphenyl-1,3-butadiene 3. 1-phenyl-4-(chlorophenyl)-1,3-butadiene 4. 1,4-bis-(p-methoxyphenyl)-1,3-butadiene S. 1,4-bis-(p-tolyl)-1,3 butadiene

6. 1,1,4,4-tetraphenyl-1,3-butadiene

7. 1,6-diphenyl-1,3,5-hexa~riene

8. 1--(2-naphthyl)-4-phenyl-1,3-butadiene

9, 1-~(2-furyl)-4-phenyl-1,3-butadiene

10. 1,4-di-(2-naphthyl~-1,3-butadiene

11. 1--(p-biphenyl)-1,3-butadiene .... . .

' ' `
`

. :

.~ :

B

12. 1,8-diphenyl-1,3,5,7-octatetraene

13~ 1,4-di-(2~methylstyryl)benzene

14. 1,3,5-tri~tyrylbenzene

15. 2,6-di~tyrylnaphthal~ene

16~ 4-styryl-p-biphenyl

17. 1,3,5-tris-(p~methoxystyryl)-benzene

18. 1,3,4-tri-(p-methoxystyryl)-benzene

19. 1,2-di-~3,4-dimethoxystyryl)-benzene

20. 1,3,5-tri~(p-methoxystilbenyl)-benzene

21. 1,1-diphenyl-2-(p-methoxystilbenyl)-ethylene

22. 1,3-di-(p-methoxystyryl)-naphthalene

23. 2,5-diphenylfuran

24. 2,5-distyrylfuran

25. 2,3,4,5-te~raphenyl~uran

26. 2,5-diphenyl-3-methoxyfurall ;

27. 2,5-diphenyl-4-methylfuran

28. 2,5-diphenylthiophene

29. 2,5-distyrylthiophene

30. 2,5-diphenylpyrrole

31. 1,2,5-triphenylpyrrole

32. 2,3,4,5-tetraphenylpyrrole

33. 1,2,3,4-tetraphenylcyclopentadiene The above compounds can he prepared by referring to the ~ollowing procedures:
Y. Hirshberg et al J~A~Co5~ ~ 72, 5120 (1950) A. Siegrist et al USP, 3,991,049 ~260/240D~
E. Seus, J. Het. Chem., 2, 318 (1965) S. King et al, J. ~. C. 5; 73, 2253 (1951) B. 1,3-diaryl-1-pyra~olines

34. 1,3-diphenyl-2-pyrazoline

35. 1-p-methoxyphenyl-3-phenyl-2-pyrazoline

36. 1-phenyl-3-p-cyanophenyl-2-pyrazoline

37. 1-phenyl-3-styryl-2-pyrazoline

38. 1-naphthyl-3-phenyl-2-pyrazoline

39~ 1-p-chlorophenyl-3-phenyl-2-pyra2O1ine

40. 1-m-chlorophenyl-3-(2,4-dimethoxyphenyl)-2-pyrazoline . ~ ... . . . . . .

,. .. . , , - . - :

K3~

-13~

41. 1-(3,4~di~hlorophenyl)-3-phenyl-2-pyrazoline

42. 1 p-methylsulfonylphenyl)-3-phenyl-2-pyrazoline

43. 1-p-acetamidophenyl~3-phenyl-2~pyrazoline

44. 5-isopropyl-1,3~diphenyl~2-pyrazoline

45. 1-p-tolyl-3~phenyl-~-pyrazoline

46. 1-p-carbom~thoxyphenyl~3-phenyl-2-pyrazoline

47. 1,3-diphenyl-5-p-acetamidophenyl-2 pyrazoline

48. 1,3,4,5-tetraphenyl-2-pyrazoline

49. 1,5-diphenyl~3-styryl-2-pyrazoline

50. 1-phenyl-3-(p~methoxystyryl)5-(p-methoxyphenyl)-2-pyrazoline

51. 1-phenyl-3-(-diethylaminostyryl)-5-(diethylamino-phenyl)-2-pyrazoline

52. lj(p-methoxyphenyl)-3-(p-diethylaminostyryl)-5-(diethylaminophenyl)-2-pyrazoline

53. 1,1'-diphenyl3-3'-bis-2-pyrazoline

54. 1-p~biphenyl-3,5-diphenyl-2-pyrazoline

55. 1-phenyl-3~(2-naphthyl-5-(p-biphenyl3-2-pyrazoline

56. 1,3~diphenyl-5-(9-anthryl)-2-pyrazoline

57. 1-phenyl-3-(p-biphenyl-5-~p-isopropylphenyl)--2-pyrazoline

58. 1,3-diphenyl-5-naphthyl-2-pyrazoline These compounds can be preared by referring to the following publications:
A. Wagner et al, Angew. Chem. Int. Ed., 5,699 (1966) R. H. Wiley et al, J. Org. Chem., 23, 732 (1958) N. A. Evans et al, Aust. J. Chem. r 27, 2267 (1974) R. Maruyama et al, Chem. Abst. 65l 13850 (1966) Neth. Appl. 6,506t722, Chem. Abst., 64, 19851c (1966) C. Isobenzofurans

59. 1,3-diphenylisobenzofuran

60. 1,3-diphenyl-4,7-di-(p-methoxyphenyl)isobenæofuran

61. 1,3-di-(p-methoxyphenyl3-3,6-diphenylisobenzofuran

62. 1,3,4,7-tekra-(p-methoxyphenyl)isobenzofuran

63. 1,3,4,7-tetraphenylisobenzouran ~, , .. . . .
~ ~ . I'.~ , , .

. . .
.
.

1~3~,3~

64. 1,3-di-(p-methoxyphenyl)isoben~ofuran

65. 1,3-di-(p-biphenyl)isobenzofuran

66. 1,3-diphenyl-5,6-dimethylisobenzofuran

67. 1,2-dLphenyl-5-methylisoben~ofuran

68. 1,3,5,6 tetraphenylisobenzofuran

69. 1,3-di-(p-biphenyl)-4,7-diphenylisobenzofuran

70. 1,3,4,7-tetra-(p-methoxyphenyl)isoben70furan These compounds are prepared by methods described in:
A. Zweig et al, J. ~m. Chem. Soc., 89, 4091 (1967) ~. Adams and M. H. Gold., J. ~m. Chem. Soc~, 62, 2038 (1940) D. Substituted Coumarins

71. 7-diethylamino-4-methylcoumarin

72. 7-dimethylamino-4-trifluoromethylcoumarin

73. 7-diethylamino-3,4-cyclopentylcoumarin

74. 7-dimethylamino-3-phenylcoumarin

75. 3-(2~-benzothiazolyl)-7-diethylaminocoumarin

76. 7-methoxy-4-methylcoumarin

77. 1,2,4,5,3H~6H,lOH-tetrahydro-g-carbethoxy-~l]-benzopyrano-(9,9a,1-gh)quinolizin-10-one

78. 1,2,4,5,3H,6H,10~1-tetrahydro-9-cyano-[1]-benzopyrano-(9,9a,lgh)quinolizin-10-one

79. 1,2,4,5,3H,6~,10H-~etrahydro-9-acetyl-[1]-benzopyrano-; ~ (9,9a-1-gh)quinoli~in-lO~one The above compounds are commercially available.

The invention is furkher illustrated by means of the following examples wherein the term "parts" refers to parts by weight unless otherwise indicated.

Examples 1-9 A stock solution was prepared from 50 parts of a 5% by weight solution of polyvinylbutyral in tetrahydrofuran, 0.5 part of 3,4-epoxycyclohexylmethyl-3,-4-epoxycyclohexane carboxylate, and 0.2 part of diphenyl . . . . . .

': . `

lill3~3B

~15-iodonium hexafluorophosphAte. To 5 part,~ of this solution was added 5 x 10 5 moles of sensitizer described in the present invention~ These solutions were then knife coated (5 x 10 2 mm wet) onto a polyester film base and then oven dried at 60C for 5 minutes. The dried film samples were then exposed to a 500 watt ultraviolet lamp at a distance of 17.8 cm through a photographic step wedge in contact with the film side of the sa~ple. After exposure, each sample was well sprayed with methanol to wash away the soluble unpolymerized material. Table I (under Exposure Time) shows the number of solid, insoluble steps remaining after the spraying. This provides a relative measure of the cure rate and ~ensitivity of the solutions.

Table I

Solid Steps at Exposure Time (min.~
ExampleSensitizer (0.25) (0.50~ (1.0) 1 none 0 0 0 2 l 0 2 2~ 3 2 0 1 6 6 7 6 8 >10 7 8 2 6 >10 ~ _s _0-15 A stock solution was prepared from 20 parts of an epoxy cresol novolac resin (having a melting point of 85-90C and an epoxide equivalent weight of 235), 30 parts acetone, ancl 0.4 parts of triphenylsulfonium hexafluorophosphate. To 5 parts of this solution was added 0.013 parts of various sensitizers according to the present invention. The solutions were then coated, dried, 63~3 ~16-and exposecl as in Examples 1-9. Table II shows the nurnber of solid steps remaini.ng a~ter washing thoroughly with acetone.

Table II
Solid Steps at Exposure Time (min ) .
ExampleSensitizer (5) (10) .
10none 0 0 13 3~ 7 Examples 16-21 _ The stock solution of Examples 1-9 with 0.2 g of diphenyliodonium hexafluoroarsenate in place of the earlier photoinitiator was used in the following ; examples. To 5 parts of this solution were added 0.01 parts of a sensitizer of this invention. These solutions were coated, dried, exposed and washed as in Examples 1-9. Table III shows the number of solid step~ remaining after washing with methanol.

Table III
.
Solid Steps at :
Exposure Time (min)~
Example Sensitizer (1.5) (2.0) (3-0) (10?
16 none 0 0 0 0 17 71 0 ~ ~ :
18 72 8 >10 19 75 0 0 2 ~-21 79 7 9 :~

.

. : : ' : :, . . : -:: . ' : -'~ ~ '`' . ' ~L3~
-17~

Exarnples 22-35 A stock solution was prepared from l00 parts of a 5~ by weight soluti.on of polyvinyl butyral in tetrahydrofuran, l~0 parts of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate, and 0.4 parts of diphenyliodium tetra~luoroborate (DPIT), tri(p-methoxyphenyl)sulfonium hexafluorophosphate (TMSH), or diphenylmethylsulfonium hexafluorophosphate (DPSH).
To 5 gram portions oE these solutions were added l0 mg oE
a sen~itizer of the present invention. These solutions were coated, dried, exposed and washed as in Examples l-9. The results are shown in Table IV.

Table IV
Solid Steps at ~xposure Time (min).
Onium Example Salt Sensitizer ~l) (2) (4) 22 DPIT none 0 0 0 (l0 min) DPIT 34 l0 26 TMSH none 0 0 0 (l0 min) 31 DPSH none 0 0 0 (l0 min) ~ ~3~j3~
, . , ~ les 3 -40 To 5 parts of a diglycidyl ether of bisphenol A
epoxy res.in having an epoxide equivalent weight of 173 was added 23 by weight of a 50/50 Inixture of triphenylsulonium hexafluoroantimonate and (p~phenylthiophenyl)diphenylsulfon-ium hexafluoroantimonate. This solution waæ then coated as in Examples 1~9. Examples o~ the coatings were then exposed through a Corning Glass Elilter No. 0-52 (which transmits only light having a wavelength greater than 334 nm) with a 275 watt sunlamp at a distance of 12.7 cm.
The exposure times required to provide a tack free surface : (S) and a tack free lower portion (L) were recorded and are shown in Table V.

Table V
Exposure Time (min) Examples Sensitizer (S) (L) . . . _ 36 none 10 10 : 38 49 0.5 20 39 50 0.67 1.33 Exam~les 41-45 Examples 36-40 were repeated except that the :~
epoxy resin was replaced by 3,4-epoxycyclohexylmethyl 3, 4-epoxycyclohexane carboxylate and the photoinitiator was replaced by a 50/50 mixture of triphenylsulfonium hydroxypentafluoroantimonate and (p-phenylthiophenyl)-diphenylsulfonium hydroxypentafluoroantimonate. The results are shown in Table VI.

.
~., : ~ ~

3l ~. .~ 3 ~i ~3 ~ ~

Tab.le VI

EK~ ro r~in Example Sensitizer (S) (L) 41 none >10 >10 g2 49 1.5 3 ~3 50 1.5 3 _a~ 46-52 10 A stock solution was prepared froln 40 parts of 3,4-epoxycyclohexyl-3,4-epoxycyclohexane carboxylate and 0.8 parts of di-(p-tolyl)iodonium hexafluoroantimonate.
10 mg of the indica~ed sensitizing dyes were dissolved in 5 g portions of the stock solution and knife coated at S.08 x 10 2 mm wet on polyester film. The samples were exposed through the previously described glass filter No~ 0-52 that transmits only light having a wavelength greater than 334 nm. Exposure was to the same lamp and the same distance as Examples 36-40. The results are shown in Table VII.

Table VII
Exposure Time (sec) ExampleSensitizin~ Dye (S~ (L) ~8 34 25 50 49 17 30 ~5 50* 63 300 36~
51* 59 20 40 52 none >600 >600 *also contains 10 mg 2,6-di-t-butyl-4-methylphenol , ~

,: - ,: : , - ~ :
: : : . . .
: .

:~, ~3~3~1~
-20~

Exa~ s 53-55 A stock solution of 1.3 parts of pentaerythritol triacrylate, 1.16 parts of polymethy:Lmethacrylate, 0.13 parts of phenyl(p-methoxyphenyl)iodonium trifluoroacetate, and 14.8 parts of acetone was prepared. lO mg of each of the sensitizers in Table VIII were dissolved in each of 5 g : sample~ of the stock ~olution and coated and evaluated as described in Examples 1-9 except exposures were made in a Collght exposure apparatus containing a 400 watt mercury lamp. Acetone was used to di.ssolve away the unpolymerized material. The table show~ the~ number of steps remaining after washing.

Table_VIII
Solid Steps at ~ Time (min) Exam~le Sensitiæer (1.0) (5.0) 53 none 0 ;

Examples 55-68 Examples 53-55 were exactly r peated, replacing the iodonium initiator with triphenylsulfonium hexafluoro-phosphate. Table IX shows the results as described above~

Table IX
Solid Steps at ExPosure Time (min) ,,,, _ . _ Exam~le Sensiti er (2.0) (5.0) 56 none 0 0 5~ 7 2 .

. ~

:

Claims

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

1. A sensitized iodonium or sulfonium photoinitiator system comprising one part of a sulfonium or iodonium photoinitiator associated with 0.01 to 10 parts of a fluorescent compound selected from polyarylenes, polyarylpolyenes, 2,5-diphenylisobenzofurans, 2,5-diarylfurans, 2,5-diarylthiofurans, 2,5-diarylpyrroles, 2,5-diarylcyclopentadienes, polyarylphenylenes, coumarins, and poly-aryl-2-pyrazolines.

2. The sensitized photoinitiator system of claim 1 wherein the photoinitiator is a sulfonium salt of the structure or wherein R1, R2 and R3 are selected from aromatic carbocyclic and aromatic heterocyclic groups of from 4 to 20 carbon atoms and alkyl radicals of 1 to 20 carbon atoms with at least one of R1, R2 and R3 being an aromatic group, Z is selected from -0-; -S-;
?=O; ?=O; O=?=O; R-? wherein R is aryl of 6 to 20 carbon atoms, or acyl of 2 to 20 carbon atoms; a carbon to carbon bond; or R4-?-R5 wherein R4 and R5 are selected from the group consisting of hydrogen, alkyl radical of 1 to 4 carbon atoms, and alkenyl radical of 2 to 4 carbon atoms; n is 0 or 1 and X- is an anion.

3 The sensitized photoinitiator system of claim 1 wherein the photoinitiator is an iodonium salt of the formulae:

wherein Ar1 and Ar2 are aromatic carbocyclic and aromatic hetero-cyclic groups of from 4 to 20 carbon atoms; W is selected from 0, S, ?=O, ?=O, O=?=O, and R6? wherein R6 is an aryl of 6 to 20 carbon atoms or acyl of 2 to 20 carbon atoms, a carbon-to-carbon bond or R7-?-R8 wherein R7 and R8 are independently selected from hydrogen alkyl groups of 1 to 4 carbon atoms, and alkenyl groups of 2 to 4 carbon atoms, b is 0 or 1, and Q is an anion.

4. The sensitized photoinitiator system of claim 2 wherein R1, R2 and R3 are selected from the group consisting of phenyl, naphthyl, thienyl, and furanyl groups.

5. The sensitized photoinitiator system of claim 3 wherein Ar1 and Ar2 are selected from the group consisting of phenyl, naphthyl, thienyl, and furanyl groups.

6. The sensitized photoinitiator system of claim 4 wherein Q- is selected from tetrafluoroborate, hexafluorophosphate, hexa-fluoroantimonate, hexafluoroarsenate, and hydroxypentafluoroanti-monate.

7. The sensitized photoinitiator system of claim 5 wherein Q- is selected from tetrafluoroborate, hexafluorophosphate, hexa-fluoroantimonate, hexafluoroarsenate, and hydroxypentafluoro-antimonate.

22 3, The sensitized photoinitiator systems of claims 2, 3 or 6 further comprising at least one free radical polymerizable mono-mer with the photoinitiator comprising from 0.01 to 10% by weight of the monomer.

9. The sensitized photoinitiator system of claim 6 further comprising at least one cationically polymerizable monomer with the photoinitiator comprising from 0.01 to 10% by weight of the monomer.

10. The sensitized photoinitiator system of claim 7 further comprising at least one cationically polymerizable monomer with the photoinitiator comprising from 0.01 to 10% by weight of the monomer.

11. The sensitized photoinitiator systems of claim 9 or 10 wherein said at least one cationically polymerizable monomer is a polymerizable epoxy resin.