JPH0515721B2 - - Google Patents

Description

[Detailed description of the invention]

BACKGROUND OF THE INVENTION The present invention relates to photocurable compositions. As is well known in the art, in the field of graphic art, 200nm
It is often desirable to cure UV-curable organic materials at wavelengths of 300 nm and above because significant absorption occurs at wavelengths below. U.S. Patent No. 4,069,054;
As shown in US Pat. Nos. 4,026,7050 and 4,250,053, various sensitizing dyes can be used to alter the spectral properties of aromatic sulfonium and aromatic iodonium salts. It is also recognized by those skilled in the art that even if a dye is found to be effective as a sensitizer for one photoinitiator, such as a triarylsulfonium salt, may be completely ineffective as a sensitizer. This is because the spectral properties of certain arylsulfonium salt-dye combinations are of an unpredictable nature. The present invention uses specific sensitizing compounds, such as aromatic hydrocarbons, specifically perylene, pyrene, anthracene, etc., according to the following formula: The arylacyldialkylsulfonium salts of can be sensitized and aromatic ketones, specifically thioxanthone, chlorothioxanthone and benzophenone can be sensitized with the following formula: This invention was made based on the discovery that it is effective as a sensitizer for the bidroxyaryldialkylsulfonium salts of. In the above formula, R is a monovalent C _(6-13) aromatic organic group or a monovalent substituted C _(6-13) aromatic organic group, R ¹ is hydrogen, C _(1-8) alkyl, or a mixture thereof. the selected monovalent group, R ² is a monovalent C _(1-13) organic group;
R ³ is a monovalent group selected from C _(1-8) alkyl, hydroxyl, C _(1-8) alkoxy, halogen and nitro, R ⁴ is a C _(1-8) alkyl group, M is a metal or semi- metal, Q represents halogen, and d is equal to 4-6. DISCLOSURE OF THE INVENTION The present invention comprises a cationically polymerizable organic material and an effective photoinitiator, wherein the photoinitiator comprises (A) a compound of the formula (A) sensitized with an effective amount of a polynuclear aromatic hydrocarbon and/or a phenothiazine; (B) a hydroxyaryl dialkyl sulfonium salt of formula (2) sensitized with an effective amount of an aromatic ketone; provide. The dialkyl phenacyl compound of formula (1) includes the following sulfonium salts. The hydroxyaryldialkylsulfonium salt of formula (2) includes the following compounds. Examples of aromatic hydrocarbon photosensitizers that can be used in combination with the dialkylarylacylsulfonium salt of formula (1) include anthracene, 1,2-benzoanthracene, coronene, perylene, phenothiazine, pyrene, tetracene, rubrene, etc. There is. Among the aromatic ketones that can be used as photosensitizers in combination with the hydroxyaryldialkylsulfonium salt of formula (2) are 9,10-anthraquinone, benzophenone, 2-chlorothioxanthone, 9-fluorenone, thioxanthone, Michler's ketone. ,
Xanthone, 4-hydroxybenzophenone, 4
-Nitrobenzophenone, acetophenone, etc. Cationically polymerizable organic materials that can be used to practice the invention include epoxy resins, such as monomeric, dimeric or oligomeric or polymeric epoxy materials containing one or more epoxy functional groups. For example, bisphenol A (4,
4'-isopropylidenzine phenol) and epichlorohydrin, or the reaction of low molecular weight phenol formaldehyde resins (novolac resins) with epichlorohydrin, either alone or with epoxy-containing compounds. Can be used in combination with a diluent. Phenyl glycidyl ether, 4-vinylcyclohexene dioxide, limonene dioxide, 1,2-cyclohexene oxide, glycidyl acrylate,
glycidine methacrylate, styrene oxide,
Diluents such as allyl glycidyl ether can be added as viscosity modifiers. Additionally, the scope of these compounds can be expanded to include polymeric materials containing epoxy end groups or side groups. Examples of such compounds include vinyl copolymers containing glycidine allylate or methacrylate as one of the comonomers. Other groups of epoxy-containing polymers that can be cured in the presence of the catalysts described above include epoxysiloxane resins,
There are epoxy polyurethanes and epoxy polyesters. Such polymers usually have epoxy functional groups at their chain ends. Epoxysiloxane resin and its manufacturing method, J.Am.Chem.Soc., 80, 632
-5 (1959) EPPlueddemnn and G.Fanger
detailed in the paper. As described in the literature, epoxy resins can be prepared in a number of standard ways, e.g.
No. 3369055, No. 3379653, No. 3398211, No.
No. 3403199, No. 3563840, No. 3567767, No.
As shown in No. 3677995, amines,
It can also be modified by reaction with carboxylic acids, thiols, phenols, alcohols, etc. Other co-reactants that can be used with epoxy resins are hydroxy-terminated softeners, such as hydroxy-terminated polyesters, which are described in the Encyclopedia of Pclymer
Science and Technology, Vol.6,
(Published by Interscience Publishers, New York,
(1967), pp. 209-271, especially p. 238. Formaldehyde thermosetting organic condensation resins that can be used in carrying out the present invention include, for example, urea type resins and phenol-formaldehyde type resins. In addition, melamine thiourea resins, melamine or urea aldehyde resins, resol-formaldehyde resins and combinations with other carboxy-, hydroxy-, amino- and mercabuto-containing resins such as polyesters, alkyds and polysulfides can be used. Examples of vinyl organic brepolymers that can be used to make the polymerizable compositions of the present invention include CH ₂ =H-O
−(CH ₂ −CH ₂ O) _o −CH=CH ₂ (here n is approx.
is a positive integer with a value up to or greater than 1000),
Polyfunctional vinyl ethers, such as 1,2,3-propane trivinyl ether, trimethylolpropane trivinyl ether, of the following formula: prepolymers, such as low molecular weight polybutadiene with a viscosity of 200 to 10,000 centapoise at 25°C. The products obtained by curing such compositions can be used in printing inks and other applications typical of thermosetting resins. Another type of organic material that can be used to make polymerizable compositions are cyclic ethers that can be converted into thermoplastics. Such cyclic ethers include oxetanes, such as 3,3-bis-chloromethyloxetane, alkoxyoxetanes (U.S. Pat. No. 3,673,216 to Schroeter, assigned to the applicant).
), oxolanes such as tetrahydrofuran, oxepanes, oxygen-containing spiro compounds, trioxane, dioxolane, and the like. Besides cyclic ethers, cyclic esters such as β-lactones, specifically propiolactone, cyclic amines, specifically 1,3,3-trimethylazetidine, and organosilicon cyclics, specifically formula: (wherein R'' represents the same or different monovalent organic group such as methyl or phenyl, and m is an integer from 3 to 8) are also included. Examples of organosilicon cyclics include: Hexamethyltrisiloxane, octamethyltetrasiloxane, etc. The products made according to the present invention are high molecular weight oils and gums. Some cationically polymerizable organic materials have the formula: R ⁶ [GR ⁷ OC Includes polyvinyl compounds having (R ⁸ )=C(R ⁹ ) ₂ ] _o ′ (3). In the above formula, R ⁶ is a polyvalent aromatic organic group, and R ⁷ is C _(1-8) alkylene. The groups R ⁸ and R ⁹ represent the same or different monovalent groups selected from hydrogen, halogen and C _(1-8) alkyl groups, G is -O- or

[Formula] is shown, and n' is an integer from 2 to 10. Examples of aromatic polyvinyl ethers included in formula (3) include the following. Arylsulfonium salt (this term is used in formula (1) below)
It has been empirically determined that the amount of the arylacylsulfonium salt or the hydroxyarylsulfonium salt of formula (2) can be used in a wide range of weight proportions relative to the cationically polymerizable organic material.
0.1 to 0.1 based on the weight of the cationic polymerizable organic material
Good results are obtained with a proportion of 10% by weight of sulfonium salts. Sensitizer (this term is hereafter referred to as
polynuclear aromatic hydrocarbon or aromatic ketone) based on the weight of the arylsulfonium salt
It was also confirmed that it can be used in a proportion of 0.01 to 200% by weight. The curable composition contains inert ingredients such as inorganic fillers, extenders, pigments, viscosity modifiers, processing aids, UV screening agents, etc. in an amount of 0 to 100 parts of filler per 100 parts of cationic polymerizable organic material. You may. The curable composition can be applied to a substrate or support such as metal, rubber, plastic, molded article or film, paper,
Can be applied to wood, glass cloth, concrete, ceramics, etc. The curable composition, ie, a cationically polymerizable organic material containing an effective amount of a sulfonium salt and a sensitizer, can be cured by exposing the composition to radiant energy, such as an electron beam or ultraviolet light. Electron beam curing requires an accelerator voltage of approx.
Can be done at 100~1000KV. Curing of the composition is preferably carried out by ultraviolet irradiation with a wavelength of 1849 Å to 4000 Å and an intensity of 5000 to 80000 microwatts/cm ² . The lamp system used to generate such radiation can consist of ultraviolet lamps, e.g. from 1 to 50 discharge lamps, e.g. Low pressure, medium pressure or high pressure mercury vapor discharge lamps can be used. The lamp has a wavelength of approximately 1849 Å to 4000 Å, preferably 2400 Å to 4000 Å
It has an envelope that allows light to pass through it. The lamp envelope is made of quartz, e.g. Spectrocil or
It can be made from Pyrex etc. Typical lamps that can be used to emit ultraviolet radiation are medium pressure mercury arc discharge lamps, specifically GE H3T7 and
It is a Hanovia 450W arc lamp. The curing process is
This can be done with a combination of different lamps, some or all of which can be used in an inert atmosphere. When using a UV lamp, curing of the organic resin can be achieved within 1 to 20 seconds by setting the irradiation flux on the substrate to 0.01 watts/parallel inch or more, such as epoxy-coated steel taken up at a rate of 100 to 1000 feet/minute. When curing the strip, curing can be carried out continuously. This strip is cut to a predetermined width suitable for use as a transformer laminate or the like.
A combination of heat and light may be used to cure the reactive composition. A combination of heat and light helps reduce total curing time. To enable those skilled in the art to easily practice the invention, the following examples are presented by way of illustration and not by way of limitation. All parts are by weight. Example 1 Various photosensitizers were screened with a 3% solution of phenacyltetramethylenesulfonium hexafluorophosphate in 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate. The screening method used was differential scanning calorimetry (DSC) using 1% by weight of photosensitizer based on the weight of the epoxy-sulfonium salt mixture. The instrument was equipped with a GE H3T7 medium pressure mercury arc lamp and a cut-off absorption filter of 300 nm. Photosensitization was observed as an exothermic peak due to polymerization of epoxy monomer in the presence of photosensitizer, as opposed to no peak in the absence of photosensitizer. The efficacy of the photosensitizer was judged qualitatively from fair to excellent based on the sharpness of the exothermic peak during DSC scanning. The following results were obtained.

[Table] As can be seen from the above screening test, polynuclear aromatic hydrocarbons are more effective in sensitizing phenacyltetramethylenesulfonium hexafluorophosphate than aromatic ketones. Example 2 In order to quantitatively confirm that the results of Example 1 were obtained, phenacyltetramethylenesulfonium hexafluoroarsenate was added to 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate. When used as a photoinitiator, the tack-free time (seconds) of the resulting photocurable composition is
Various polynuclear aromatic hydrocarbon sensitizers were measured in comparison with various aromatic ketone sensitizers. The following procedure was used. A stock solution was made from 3 g of phenacyltetramethylenesulfonium hexafluoroarsenate and 100 g of 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate dissolved in 10 ml of acetone. 5 of this stock solution
20 mg of various photosensitizers were added to part g. These solutions were applied as 3 mil thick films onto glass plates and irradiated with a GE H3T7 medium pressure mercury arc lamp fitted with a Pyrex filter to block radiation below 300 nm. The distance from the sample to the lamp was 6 inches. The tack-free time obtained is as follows.

[Table] The above results demonstrate that polynuclear aromatic hydrocarbons are effective as sensitizers for phenacyltetramethylenesulfonium hexafluoroarsenate. Example 3 Photocopy of 50 g of tetrahydrofuran, 2.5 g of polyvinyl butyral, 0.5 g of 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate and 0.2 g of phenacylpentamethylenesulfonium hexafluoroarsenate A curable mixture was prepared. 5 mg of perylene was added to 5 g of this photocurable mixture. The sensitizer-containing photocurable mixture and the perylene-free photocurable mixture were applied to a glass plate. The coated glass plate was dried and the resulting film was exposed to a GE H3T7 medium pressure mercury arc lamp with a 300 nm glass filter for 4 minutes through a contact mask. The exposed film was sprayed with methanol to remove the uncrosslinked portions of the image. The perylene sensitized film showed a clearly shaded image, whereas the control film containing no sensitizer showed no visible image. Although the above examples relate to only some of the numerous variables encompassed by the present invention, the present invention covers a wide range of photocurable compositions and uses thereof, as indicated in the description preceding the examples. It should be understood regarding sensitizers.

Claims (1)

Claims: 1. A compound of the following formula: [R-O ‖ C, sensitized with a cationically polymerizable organic material and an effective amount of a photosensitizer selected from perylene, pyrene, anthracene, phenothiazine or mixtures thereof. An effective amount of a photoinitiator of C(R ¹ ) ₂ S(R ² ) ₂ ] ⁺ MQ _d ^- (R in the above formula is a monovalent C _(6-13) aromatic organic group and a monovalent substituted C _{(6 -13)} A group selected from aromatic organic groups, R ¹ is a monovalent group selected from hydrogen, C _(1-8) alkyl and mixtures thereof, R ²
is a monovalent C _(1-13) organic group or forms a divalent organic group which can be paired to form a cyclic structure selected from the group consisting of [Formula] and [Formula], and M is metal or metalloid, Q represents halogen, d equals 4 to 6)
A composition that can be photocured at wavelengths of 300 nm or more. 2. The photocurable composition according to claim 1, wherein the photoinitiator is phenacyltetramethylenesulfonium hexafluoroarsenate. 3. The photocurable composition according to claim 1, wherein the cationically polymerizable organic material is an epoxy resin or a mixture of epoxy resins. 4. The photocurable composition according to claim 1, wherein the photosensitizer is perylene. 5. The photocurable composition according to claim 1, wherein the cationically polymerizable organic material is a difunctional vinyl ether. 6. The photocurable composition according to claim 1, wherein the photosensitizer is anthracene. 7. The photocurable composition according to claim 1, wherein the photosensitizer is a phenothiazine.