JPS6121244B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to ultraviolet (UV) curable compositions and methods of curing compositions by radical generation. In particular, this invention relates to the radical curing of mixtures of acrylic resins and certain unsaturated polyesters using triarylsulfonium salt photoinitiators. Prior to this invention, radical photocurable mixtures, such as unsaturated polyesters, as described in Passalenti et al., U.S. Pat. Nos. 3,616,366 and 3,627,657,
When using photoinitiators such as benzoin and its derivatives, it has had to be stabilized with substances such as aryl phosphites. for example,
It has been found that without the addition of stabilizers to such photocurable resin mixtures, the shelf life of this material is often less than 6 weeks under atmospheric conditions. However, even with the use of stabilizers, the shelf life of radical photocurable organic resins is often no more than 6 to 12 months at ambient temperature. Abrams et al. U.S. Patent No.
As disclosed in US Pat. No. 3,028,361, sulfonium salts can be used as stabilizers for polyester compositions that are thermally cured with peroxide catalysts. As disclosed in Smith US Pat. Nos. 3,729,313 and 3,808,006, the storage stability of radical photocurable organic resin mixtures is improved when complex catalyst systems are used. For example, Smith uses diaryliodonium compounds as photoinitiators to sensitize organic dyes, such as acridine, and photodegradable organohalogen compounds, such as 2-methyl-
It teaches that it can be used in combination with 4,6-bis(trichloromethyl)-s-triazine.
Thus, there is no need for the addition of stabilizers or the use of combinations of additional ingredients such as the organic dyes and substituted triazines disclosed in the aforementioned Smith patent, and at the same time it does not require the addition of stabilizers or the use of combinations of additional ingredients such as the organic dyes and substituted triazines disclosed in the aforementioned Smith patent, while at the same time providing a It is desirable to radically cure a variety of resins, such as acrylic resins and mixtures of aliphatically unsaturated polyesters and vinyl aromatic organic compounds, by using photoinitiators with long shelf lives. The present invention provides a triaryl compound having the following formula: [(R) ₃ S] ⁺ [Y] ⁻ () (in the formula, R is a monovalent C ₆ to C ₁₃ aromatic group, and Y is an anion). Sulfonium salts are used as photoinitiators to rapidly photocure free radical curable organic resins, such as thiol-ene resins, acrylic resins, and blends of aliphatically unsaturated polyesters with vinyl aromatics. This is based on the discovery that this can be achieved by UV irradiation for a period of time, for example 0.5 to 1 minute or less. Furthermore, it has been confirmed that such photocurable organic resin mixtures have a long shelf life of more than 6 months at ambient temperature in the absence of phenolic or quinone inhibitors. As described in applicant's patent application (1) of the same date, Y in the formula can be an M(Q) _d group,
M represents a metal or metalloid, Q represents a halogen group, and d has a value of 4 to 6 and can be, for example, AsF ₆ . Such M(Q) _d triarylsulfonium salts are added to radically curable organic resins, such as acrylic resins or aliphatically unsaturated polyesters, in the form of mixtures with organic compounds such as epoxy monomers, such as epoxy acrylates, or When a cationically curable moiety such as oxirane oxygen is contained in the polymer skeleton of a saturated polyester, for example by including an oxirane unit as a chemical bonding unit, when used in combination and irradiated with such a photocurable mixture, , organic resins can be radically and cationically cured simultaneously. The present invention comprises: (A) an oxirane oxygen-free free radical curable organic resin selected from the group consisting of acrylic resins and thiol-ene resins; and (B) 0.1 to 15% by weight of the total of (A) and (B). A photocurable organic resin composition comprising a triarylsulfonium salt of the formula is provided. The present invention also provides (C) the following formula: A free radical curable organic resin having a chemically bonded oxirane oxygen represented by the following formula: [(R) ₃ S] ⁺ [X] ⁻ ( ) (R in the formula is as described above, and X represents an anion selected from the group consisting of halogen, NO ₃ HSO ₄ and H ₂ PO ₄ ). Compositions are also provided. Illustrative examples of groups represented by R in the formulas include C ₆ to C ₁₃ aromatic hydrocarbon groups, such as phenyl, tolyl, naphthyl, anthryl and 1 to 4
and aromatic heterocyclic groups such _{as pyridyl} , furfuryl and the like. Examples of anions represented by Y in the formula include halogen, such as chlorine, bromine, fluorine, and iodine; NO ₂ , HSO ₃ , ClO ₄ ^- , etc.; MQ _d ,
For example, BF ₄ ^- , PF ₆ ^- , AsF ₆ ^- , SbF ₆ ^- , FeCl ₄ ⁼ ,
SnCl ^- , SbCl ₆ ^- , BiCl ₅ ^- , AlF ₆ ^- , GaCl ₄ ^- ,
Examples include InF ₄ ^- , TiF ₆ ^- , and ZrF ₆ ^- . Other metals included in M include transition metals such as Zr, Sc,
V, Cr, Mn, Cs, etc.; rare earth elements, such as lanthanides, specifically Ce, Pr, Nd, etc.; actinides, specifically Th, Pa, U, Np, etc.; and semimetals, such as B, P, As etc. Triphenylsulfonium salts encompassed by formulas and can be made by methods described in the following literature. JWKnapczyk & WEMcEwen, J.Am.
Chem.Soc., 91, 145 (1969). ALMaycock & GABerchtold, J.Org.
Chem.Soc., 35, No.82532 (1970). HMPitt U.S. Patent No. 2807648. E.Goethals & P.DeRadzetzky, Bul.Soc.
Chim.Belg., 73, 546 (1964). HMLeicenster & FW Bergstrom, J.Am.
Chem.Soc., 51, 3587 (1929), etc. Some examples of triarylsulfonium salts included in the formula are shown below. Examples of triarylsulfonium salts included in the formula are shown below. etc. (D is O, S, S=O, C=O, O=S=O,
Aliphatic unsaturated polyesters that can be used in the radically curable composition of the present invention include organic polycarboxylic acids such as phthalic acid, isophthalic acid, adipic acid, glutaric acid, malonic acid, succinic acid, Suberic acid, azelaic acid, tetrachlorophthalic acid, and tetrahydrophthalic acid are chemically bonded via ester bonds with one or more aliphatic unsaturated polycarboxylic acid units, such as fumaric acid, maleic acid, citraconic acid, and itaconic acid units. conjugate these polycarboxylic acids with glycols, such as 1,4-butenediol,
1,4-cyclohexanedimethanol, ethylene glycol, diethylene glycol, triethylene glycol, etc., 1,2-propylene glycol, isomers of dihydroxybenzene, bisphenols, such as 2,2-diphenyl-phenylopropane, halogenated bisphenols It can be a reaction product obtained by reacting with etc. Experiments have shown that in order to obtain an effective curing action, it is necessary to use at least 5 to 50 mole % of aliphatically unsaturated polycarboxylic acid units, based on the total number of moles of polycarboxylic acid units in the polyester. I confirmed it. Additionally, small amounts of mono- and polyfunctional organic acids and glycols, such as palmitic acid, pyromellitic acid, glycerin, cyclohexanol, etc., can be incorporated into the polyester to achieve certain desirable properties. The molecular weight of the unsaturated polyester can range from about 2,000 to 10,000, with molecular weights ranging from about 2,000 to 6,000 being preferred. Suitable unsaturated polyesters are reaction products of fumaric acid, isophthalic acid and propylene glycol having fatty unsaturation as defined above. Vinyl aromatic organic compounds that can be used in combination with aliphatic unsaturated polyesters include, for example, styrene, vinyltoluene and N-vinylpyrrolidone. The proportion of vinyl aromatic compounds such as styrene that can be used in combination with unsaturated polyesters is
It varies widely depending on the degree of unsaturation of the polyester and the desired viscosity of the mixture. For example, 1 aliphatic unsaturated polycarboxylic acid unit in polyester
It has been found that effective results are obtained using 0.5 to 10 moles of vinyl aromatic compound per mole. In addition to the above-mentioned vinyl aromatic organic compounds, examples of substances that can also be used in combination with aliphatic unsaturated polyester compounds include methyl methacrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, acrylonitrile, vinyl acetate,
Examples include diethyl fumarate, dipropyl fumarate, diallyl phthalate, and the like.
Additionally, small amounts of polyfunctional monomers, e.g. 1,3
- Butylene glycol diacrylate, polyethylene glycol diacrylate, ethylene glycol diacrylate, etc. can be used to increase the crosslink density of the cured polyester. Acrylic resins that can be used to make the photocurable compositions of the invention include polymers and copolymers derived from esters of acrylic and methacrylic acids, such as Acryloid polymers (manufactured by Rohm and Haas Company). )
and Elvacite resin (Dupont
(manufactured by Ccmpany). Examples of such monomers that can be used in combination with the organic polymers include esters of acrylic acid and methacrylic acid, such as methyl methacrylate;
Butyl methacrylate, butyl acrylate, ethyl acrylate, hydroxyethyl acrylate, hydroxymethyl acrylamide, methoxyethyl acrylate, 2-ethoxyethyl methacrylate, ethylhexyl acrylate, hexadecyl acrylate or cyclohexyl acrylate. Small amounts of vinyl esters or ethers, such as vinyl acetate, vinyl propionate,
or also contains butyl vinyl ether, vinyl aromatics such as styrene, vinyltoluene, t-butylstyrene or p-chlorostyrene, or other unsaturated monomers such as diethyl fumarate, acrylonitrile, N-vinyl-2-pyrrolidone or vinylidene chloride. can be done. The monomers include polyfunctional acrylate and methyl acrylate monomers, such as neobentyl glycol diacrylate, hexanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, or methacrylated oligomer compositions, such as acrylate-terminated polyesters. and polyurethane. In addition to the above resins, triarylsulfonium salts of the formula can be used in combination with thiol-ene resins. Examples of thiol-ene resins are Kerr et al., U.S. Pat.
Nos. 3,697,402, 3,700,574 and 3,661,744. Using a triarylsulfonium salt of the formula,
oxirane-containing aliphatic unsaturated polyesters or aliphatic unsaturated polyesters with chemically bonded oxirane oxygen in combination with vinyl aromatic compounds,
or, for example, glycidyl acrylate, glycidyl methacrylate, bisphenol-A-diglycidyl ether, 4-vinylcyclohexane dioxide, 3,4-epoxycyclohexyl-3',
4′-epoxycyclohexane carboxylate,
diglycidyl phthalate, cyclohexene oxide, 1,4 _{-butanediol diglycidyl ether, C4-C30 α} -olefin oxide, epoxy-novolac resins such as DEN431, DEN438,
DEN439 (Dow Chemical)
Radical curing of the above resins with or without chemically bonded oxirane oxygen in combination with compounds such as A. In addition to the compounds described above, oxirane-containing polymeric materials having epoxy end groups or pendant groups can also be blended with the acrylic resin or unsaturated polyester compositions described above. Examples of these materials are vinyl copolymers containing glycidyl acrylate or methacrylate as one of the comonomers. Other types of epoxy-containing polymers amenable to radical curing using triarylsulfonium catalysts of the formula are epoxy-siloxane resins, epoxy-polyurethanes and epoxy-polyesters. Such polymers usually have epoxy functionality at the end of the chain. Epoxy siloxane resin and its manufacturing method are EP
Plueddemann & G. Fanger, J. Am. Chem. Soc.
, 81, 632-5 (1959). As seen in this literature, epoxy resins can be prepared using a number of standard methods, such as amines, carboxylic acids, thiols,
It can be denatured by reaction with phenol, alcohol, etc., and such denaturation is described in U.S. Pat.
No. 3379653, No. 3398211, No. 3403199, No. 3563850
No. 3567797, No. 3677995, etc. Other examples of epoxy resins that may be used can be found in the Encyclopedia of Polymer Science and Technology.
"polymer Science and Technology" (Inter-
Science Publishers, New York, 1976)
Volume 6, pages 209-271. When carrying out photocuring of radically polymerizable materials using triarylsulfonium salts of the formula, 0 to 95 mole % of cationic functional groups and 5 It has been determined that it is desirable to use ˜100 mol % of radical functionality. Radical or cationic functional sites are present as part of the compound in the mixture.
Alternatively, it can be present as chemically bonded multivalent units as part of a polymer or copolymer. James V. Crivello U.S. Patent Application No. 638981, No. 638982, Assigned to Assignee.
No. 638983, No. 638992, No. 638993 and No.
No. 638994 (December 9, 1975) describes the use of epoxy resins or various vinyl organic and cyclic organic compounds.
Cationically polymerizable materials obtained by adding halonium salts and onium salts of Va and Wa group elements are described. Specifically, triphenylsulfonium salts encompassed by the formula are used as photoinitiators for epoxy resins in U.S. Patent Application No. 638,982 and as photoinitiators for vinyl organic and cyclic compounds in U.S. Patent Application No. 638,981. Used as an initiator. However, the patent application (1) dated the same date as the above-mentioned main application
According to the present invention and the above-mentioned patent application, a markedly different advantage is obtained in that the mixture used in the present invention is simultaneously radically and cationically photocured. The radical curable composition of the present invention includes an organic resin.
Fillers, e.g. 100 parts per 100 parts, may be included; other materials that may be added include dissipating agents, thixotropic agents, dyes and pigments, such as barite, permanent white, gypsum, calcium carbonate, quartz, diatomaceous earth. Silica, synthetic silica, clay, talc,
Asbestos, mica, bentonite, aerogel, glass fiber, basic lead carbonate (lead white), antimony oxide,
Examples include lithopone, titanium dioxide, ultramarine, and aluminum powder. To cure the photocurable compositions of the present invention, the compositions are heated to a temperature within the range of 150<0>C to 250<0>C, or radiant energy, such as electron beam or ultraviolet light, is used. Electron beam curing is approximately 10~
It can be done with an accelerator voltage of 1000KV. Preferably, curing of the composition is accomplished by ultraviolet irradiation with a wavelength of 1894 Å to 4000 Å and an intensity of at least 5000 to 80000 microwatts/cm ² . The lamp system used to generate such radiation may consist of ultraviolet light bulbs, e.g. from 1 to 50 discharge lamps;
Specifically, it is possible to use xenon, metal halides, metal atmospheres, such as low-pressure, medium-pressure or high-pressure mercury vapor discharge lamps having an operating pressure of several mmHg to about 10 atmospheres. The envelope of a discharge lamp is approximately the wavelength
It shall transmit light of 1849 Å to 4000 Å, preferably 2400 Å to 4000 Å. The discharge lamp envelope can be made of quartz, such as Spectrocil or Pyrex. Typical discharge lamps that can be used to obtain ultraviolet light are medium pressure mercury arc lamps, e.g.
CEH3T arc lamp and Hanovia450W arc lamp. Curing can be carried out with various lamp combinations, some or all of which can be operated under an inert atmosphere. In order to further deepen the understanding of the present invention, examples are shown below. The examples are illustrative and are not intended to limit the invention. All "parts" are parts by weight. Example 1 Various radical curable compositions were prepared using butyl benzoin ether (Triganol 14) and triphenylsulfonium hexafluoroarsenate as photoinitiators. The first radically curable organic resin contained a mixture of 33% by weight styrene and 67% by weight aliphatically unsaturated polyester in the form of the reaction product of isophthalic acid, fumaric acid and diethylene glycol. Other radically curable organic resins contained equal weight parts of methyl methacrylate and polymethyl methacrylate. The third radical curable organic resin was trimethylolpropane triacrylate. The above photoinitiator was added to each of these radically curable organic resins in an amount of 3% by weight.
amount was added. The above radical curable organic resin,
Equimolar amounts of triphenylsulfonium hexafluoroarsenate and Triganol14 photoinitiator (from Noury Chemical Ccmpany)
An additional series of photocurable resins were prepared using Each of the photocurable mixtures prepared above was applied to a steel plate to a thickness of approximately 2 mils, and the treated steel plate was
A curing furnace equipped with a H3T7 medium pressure mercury arc lamp was run approximately 8 inches from the arc lamp. Table 1 shows the conveying speed (feet/min) required to form a tack-free film on the steel plate as it passes through the hardening furnace.

[Table] This result shows that triphenylsulfonium salt is almost equivalent to Triganol 14 as a UV radical photoinitiator. Example 2 A series of formulations of trimethylolpropane triacrylate and 1% by weight, based on total weight, of various onium salts were prepared. The formulation was applied to a glass plate 1.5 mil thick and spaced 6 inches apart.
Irradiation was performed with a GEH3T7 arc lamp to determine whether the particular onium salt used could initiate radical curing. The results are shown in Table 2. “〇” in the hardening column
indicates that a tack-free film was obtained, and "x" indicates that a tack-free film was obtained.
indicates that the formulation remained uncured. Cure time indicates length of exposure to H3T7 arc lamp.

[Table] This result shows that the triarylsulfonium salts according to the invention must be used to carry out radical polymerization. No cure occurs using diphenylbenzylsulfonium fluoroborate because the methylene groups interfere with the results achieved by the present invention. Example 3 A 1% solution of triphenylsulfonium hexafluorophosphate in hydroxypropyl acrylate was irradiated according to the procedure of Example 2. A polymer with 98% conversion of monomer was obtained within 1 minute. Example 4 To 5 parts of glycidyl acrylate was added 0.15 parts (3% by weight) of triphenylsulfonium chloride. The mixture was applied to a glass plate to a thickness of 3 mils using a GE H3T7 mercury lamp from a distance of 4 inches.
Irradiation was performed for 20 seconds. The mixture was observed to polymerize. This polymer is soluble in methylene chloride;
Therefore, it was not crosslinked. This indicates that the polymerization took place via the acrylate double bond. Example 5 A 1% solution of triphenylsulfonium chloride in a 1:1 (by weight) mixture of triallyl isocyanurate and trimethylolpropane trithioglycolate was applied as a 2 mil thick film to an aluminum plate. GE this film
Exposure to H3T7 mercury lamp for 15 seconds. A hard polymeric coating was obtained. Example 6 1% S-phenylthioxanthylium hexafluoroarsenate in a mixture of 33% styrene and 67% unsaturated polyester as in Example 1: was added. A layer of glass cloth was impregnated with this solution. The impregnated fabric was then irradiated for 1 minute with a GE H3T7 mercury lamp from a distance of 4 inches. A stiff cured composite was obtained after exposure. In addition to the triarylsulfonium salts of formulas and, other triarylsulfonium salts that can be used in the present invention to prepare photocurable compositions include compounds of the following formula. [(R) _a (R ¹ ) _b S] ^- [Y′] ^- () As mentioned above, R in the formula represents a divalent aromatic group or a divalent heterocyclic group, and ^Y ' is Y when a compound of formula is used in place of a compound of formula I
and when a compound of the formula is used in place of a compound of the formula, it is the same as X, a is 1 or 3, b is 0 or 1, S is trivalent and R alone or R
and R ¹ . The above examples represent only a few of the vast number of examples encompassed by the photocurable compositions and curing methods of the present invention, and include a wide variety of organic resins and triarylsulfonium compounds as previously described. Salt can be used.

Claims (1)

[Claims] 1 (A) Oxygen-free free radical curing of an oxirane selected from the group consisting of acrylic monomers, mixtures of acrylic monomers and acrylic polymers, unsaturated polyesters, and mixtures of unsaturated polyesters and vinyl aromatic compounds. organic substance and (B) 0.1 to 15% by weight of the following formula: [(R) ₃ S] ⁺ [Y] ⁻ (wherein R is a C ₆ to C ₁₃ aromatic organic group and Y
is a free radical photocurable organic crude product consisting essentially of a triarylsulfonium salt of 2. The composition according to claim 1, wherein the acrylic resin is a mixture of methylmethacryl and polymethylmethacrylate. 3. The composition according to claim 1, wherein the triarylsulfonium salt is a triphenylsulfonium salt.