JPS6365688B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to ultraviolet curable compositions comprising a polyolefin component, a polythiol component, and an effective amount of a photoinitiator. Prior to this invention, U.S. Pat. No. 3,697,395 to Kehr et al.
Photocurable compositions such as those described in US Pat. Furthermore, Kehr et al.
Division of Organic April 8-13, 1973
Coatings and Plastics Chemical Volume 33, No. 1
As discussed in No. 1, p. 295, photocuring of such polythiol-polyene systems has been shown to be a free radical cure that requires an initiator to improve the shelf life of the composition. . A photocure rate accelerator, such as benzophenone, is used to carry out the addition reaction between the polyene and polythiol components to produce the elastomeric coating. Although effective results are obtained with the free radical initiated cure system of Kehr et al., it is necessary to use an effective amount of initiator to compensate for premature gelation. However, experience has shown that the use of initiators to improve the shelf life of curable polythiol-polyene mixtures also increases the curing time of these mixtures. As shown by the Kehr et al. patents, cure times of minutes to days are not unusual. The present invention is based on the discovery that liquid polythiol-polyene mixtures can be converted to elastomeric solids by polycondensation processes. A photocurable mixture is provided that does not require the use of an initiator and can be cured into coatings having thicknesses of up to 20 mils or more. By using an onium salt photopolymerization initiator in place of the free radical photocure rate accelerators of the prior art, curing is more rapidly achieved. Onium salts such as triphenylsulfonium fluoroborate can release Lewis acid catalysts upon exposure to ultraviolet light. Preferred onium salts that may be used in the photocurable compositions of the present invention include compounds such as triarylsulfonium hexafluoroarsenate. Diazonium compounds, such as those shown by Schlesinger, U.S. Pat. No. 3,703,296, although less effective than the above-mentioned onium salts because of the need for stabilizers and undesirable side reactions such as foaming and discoloration due to the release of nitrogen, Used in condensation polymerization based on Lewis acid release. The present invention provides a curable composition comprising a polyolefin component, a polythiol component, and an effective amount of an ultraviolet photopolymerization initiator represented by the following formula. (1) (Y ⁺ ) _J (MF ₆ ) ^(6-L) where M is B, P, As or Sb, Y ⁺ is [(R)a(R ¹ )bQ] ⁺ [(R)c (R ² ) d (R ³ ) eD] ⁺ and [(R) f (R ⁴ ) g (R ⁵ ) hZ] ⁺ , and R is a monovalent aromatic organic group, R ¹ is a divalent aromatic organic group, R ² is a monovalent organic aliphatic group selected from alkyl, cycloalkyl and substituted alkyl;
R ³ is a polyvalent organic group forming a heterocyclic or condensed ring structure selected from aliphatic groups and aromatic groups;
R ⁴ is a monovalent organic aliphatic group selected from alkyl, alkoxy, cycloalkyl and substituted derivatives thereof, R ⁵ is a polyvalent organic group forming an aromatic heterocycle or a fused ring structure, where Q is I ,Br,
halogen group such as Cl, F etc., D is a group a element selected from sulfur, selenium and tellurium, Z is a group a element selected from N, P, As, Sb and Bi, a is 0 or 2 , b is 0 or 1, a+b is equal to 2 or the valence of Q, c is 0 or 3, d is an integer from 0-2, e is 0 or 1
and c+d+e is equal to 3 or the valence of D, and f
is an integer of 0-4, g is an integer of 0-2, h is an integer of 0-2
The integer f+g+h is equal to 4 or the valence of Z, J=6-L L is equal to the valence of M, and is equal to an integer from 2 to 7. R is the same or different aromatic carbocyclic or heterocyclic group having 6 to 20 carbon atoms, such as C _1-8 alkoxy, C _1-8 alkyl, nitro, chloro, etc. It may be substituted with 1-4 monovalent groups selected from. R is especially phenyl, chlorophenyl, nitrophenyl, methoxyphenyl, pyridyl and the like. The groups included in R ¹ are

【formula】

It is a divalent group such as [Formula]. Group ^R2 is _C1-8 like methyl, ethyl etc.
alkyl group, -C ₂ H ₄ OCH ₃ , -CH ₂ COOC ₂ H ₅ , -
With substituted alkyl groups such as CH ₂ COCH ₃ etc.
The group R ³ includes structures such as:

【formula】 【formula】

【formula】

[Formula] etc. The group R ₄ can be a C _1-8 alkyl group, a C _3-8 cycloalkyl group, a haloalkyl, a substituted alkyl group such as chloroethyl, an alkoxy group such as OCH ₂ C ₆ H ₅ and OCH ₃ , CnH ₂ nOCH ₃ and the like. Included in the group R ⁵ are, for example, the following groups.

【formula】 【formula】

【formula】

【formula】

【formula】

【formula】

[Formula] In the formula, Q' is selected from O, CH ₂ , N, R and S, and Z' is -O-, -S- and

and R' is a monovalent group selected from hydrogen and hydrocarbons. Halonium salts encompassed by the formula include, for example

【formula】

【formula】

【formula】

【formula】

[Formula] Group a onium salts included in the formula are, for example, etc. Group a onium salts included in the formula include, for example: It is. Some of the photoinitiators used in the curable compositions of the invention include arylhalonium bisulfates and corresponding hexafluoro acids or salts, e.g.
Y ¹ MF ₆ (wherein Y ¹ is hydrogen, alkali metal ion,
alkaline earth metal ions or transition metal ions) under aqueous conditions. The halonium salts of the present invention, in addition to the metathesis described above to produce the corresponding halonium salts, can also be prepared by MCCaserio et al., J. Amer. Chem. Soc., 81 ,
336 (1959) or M.C. Beringer et al., J. Amer.
Chem.Soc., 81 , 342 (1959), it may also be prepared by using silver compounds such as silver oxide or silver tetrafluoroborate, which are reacted with suitable diarylhalonium salts. . Group a compounds such as sulfonium, selenium and tellurium compounds (where Y in the formula includes an X group) can be prepared by the methods described in the following documents: JWKnapczyk and W.E.
McEwen, J.Amer.Chem.Soc., 91 , 145 (1969),
ALMaycock and GABerchtold, J.Org.
Chem., 35 , No. 8, 2532 (1970), HMPitt, U.S. Patent No. 2807648, E. Goethals and P. De
Radzetzky, Bull, Soc.Chim.Belg., 73 546
(1964), H.M. Leicester and F.W. Bergstrom,
J.Amer.Chem.Soc., 51 3587 (1929). Among the methods that can be used to prepare Group A onium salts, arsonium, antimonium and bismasonium salts (wherein Y is a Z group) are described by Goerdeler, Methoden der
Organischen Chemie 11/2, 591-640 (1958)
and K. Sasse, ibid., 12/1 79-112 (1963).
can be found in Some polyolefins that can be used in the photocurable compositions of the present invention are disclosed in Kehr et al.
No. 3697396, column 3, lines 5-55 and column 4,
Shown in lines 1-15. Generally, polyolefins having the following formula can be used in the practice of this invention. (2) [A]—[—D]x where x is an integer of at least 2, A is a polyvalent organic group or an organosilicon group that does not contain reactive olefinic unsaturation, and contains chlorine, Carbon, oxygen,
consists essentially of chemically bonded atoms such as nitrogen, phosphorous, silicon, etc., and mixtures thereof, and D is an olefinically unsaturated monovalent organic group as described in Kehr et al., U.S. Pat. It includes, but is not limited to, the groups shown in Column 3, Lines 5-41 of No. 3697396. A typical example of a polyolefin component that can be used in the practice of this invention is a polyurethane obtained by reacting a poly(alkylene-ether) polyol with an aliphatically unsaturated monoisocyanate, said polyol being an unsaturated monoisocyanate. Hydrolic alcohol and organic polyisocyanate can be reacted. The production of the polyurethanes described above is carried out by standard techniques using organometallic catalysts. Polythiol components that can be used in the practice of this invention may have a molecular weight of 50 to about 20,000;
It is also included in the following expression. (3) G(-SH)y In the formula, G is a polyvalent organic group containing no aliphatic unsaturation, and y is an integer of 2 or more. G is, in particular, an organic group which may contain, in addition to chemically bonded carbon atoms, carbon and hydrogen atoms, carbon and oxygen atoms, and silicon and oxygen atoms, heteroatoms such as N, P or O. be. These thiols include esters of acids and thiols, including polythiols, such as ethanedithiol, hexamethylenedithiol, tolylene-2,4-dithiol, and certain polymerized polythiols, such as thiol-terminated ethylcyclohexyl dimercaptan polymers. It is. Certain polythiol compounds, such as thioglycolic acid,
Esters of α-mercaptopropionic acid and β-mercaptopropionic acid with polyhydroxy compounds such as glycols, triols, tetrols, pentols, and hexols are preferred because of their relatively low odor. Some examples of polythiols that can be used to produce the curable composition of the present invention are as follows. Ethylene glycol bis(thioglycolate), ethylene glycol bis(β
-mercaptopropionate), trimethylolpropane bis(thioglycolate). Preferred polythiol compounds are characterized by the substantial absence of mercaptan-like odors, providing a substantially odor-free coating product. The curable composition of the present invention can be used as an organic solvent-free composition or as a 100% solids coating material containing a polyolefin component and a polythiol active component and the photoinitiator. . The curable compositions of the present invention can be applied onto a variety of substrates such as plastics, glass, wood, steel, and aluminum.
It can be applied as a dispersion or emulsion in an aqueous medium. Additionally, the curable compositions of the present invention can be pumped, poured, siphoned, sprayed, doctored, or otherwise applied onto the substrate in any desired manner. The curable composition may also, prior to curing,
It can be mixed with other monomeric or polymeric materials, such as thermoplastics, thermoset elastomers, to modify the curing properties of the cured product. If, prior to curing, the reactive functional groups are maintained in substantially stoichiometrically equivalent amounts in the curable mixture of the polyolefin component containing carbon-carbon double bond unsaturation and the SH-containing groups of the polythiol component; The resulting curable coating composition will have optimal coating properties. The molar ratio of ene groups to thiol groups in the UV curable composition is from about 0.2/1 to about 5/1, preferably from about 0.75/1 to about
It is 1.5/1. Desirable properties of the curable compositions of the present invention include, for example, flexibility, solvent resistance, weather resistance,
Includes insulation. The order of addition of the various components into the curable mixture is not critical. For example, the photoinitiator may be added directly to the mixture of polyolefin and polythiol and the photoinitiator, or may be prepared in situ. The photoinitiator may be present in a proportion of 0.25-10% by weight, preferably 0.5-3% by weight, based on the weight of the UV-curable composition. Also,
antioxidants, accelerators, dyes, inhibitors, activators,
Fillers, pigments, antistatic agents, flame retardants, thickeners, thixotropic agents, surfactants, viscosity modifiers, bulking oils,
Additives such as plasticizers, tackifiers and other ingredients commonly used to modify the properties of curable coating compositions can be used. Fillers such as natural or synthetic resins, carbon black, alumina, wood powder, mica, silica, aluminum in an amount of 500 parts or more per 100 parts of the curable mixture, preferably about 0.5% per 100 parts of the curable mixture. It can be used in an amount of about 300 parts. Medium pressure mercury arc lamps, such as Hanovia lamps and GEH3T7 lamps, RS
Conventional sources of ultraviolet light such as solar lamps, xenon flash lamps, and carbon arc lamps can be effectively used. Uses of the curable compositions of the invention include, for example, adhesives, caulks, elastomeric sealants, coatings, incapsulating or potting compounds, liquid castable elastomers, thermoset resins, textile fabrics. , an impregnating agent for textile fabrics and other porous substrates. Furthermore, this curable composition can be used as a matrix material for thermosetting resins or elastomers, such as glass fibers, carbon fibers, steel fibers, etc., as molding mixtures for producing gaskets and diaphragms. To enable those skilled in the art to better practice the present invention, the following examples are included by way of illustration:
These are not intended to limit the invention.
All parts in the examples are parts by weight. Example 1 A sufficient amount of triphenylsulfonium hexafluoroarsenate is added in crystalline form to an equimolar mixture of trimethylolpropane trithiol glycolate and diallylphthalate containing about 3% by weight of photoinitiator. The curable mixture was applied to the surface of a glass substrate using a pull rod to produce a coating approximately 3 mm thick. The treated glass substrate was then placed under a GEHT37 medium pressure mercury lamp at a distance of approximately 6 inches. Curing of the curable mixture was achieved with an exposure time of about 1 minute, as determined by measuring the time to surface gas tackiness of the treated substrate. Example 2 Approximately 3% by weight equimolar solution of trimethylolpropanol triarylate and diallyl maleate
sensitized with triphenylsulfonium hexafluoroarsenate. Next, the above curable composition was applied to the surface of the glass substrate using a tension rod. The treated substrate was then exposed to a UV light source for 20 seconds as described in Example 1, which rendered the surface of the treated substrate tack-free. Example 3 Additional equimolar mixtures of polyolefin and polythiol components were blended with about 3% by weight photoinitiator and cured according to the method of Example 1.
The following table shows the ingredients in the mixture and the cure time, which is measured as the time the treated glass substrate becomes tack-free after coating the curable composition to a thickness of 3 mils.

[Table] Carbonell propane sulfonium tetate lithiol glyfluoroborate licorate

[Table] Luisosulfonium hexa
Anneleh Safluorobo
Torate
Example 4 0.6 mol of allyl alcohol was added dropwise to a stirring mixture of 95 g (0.2 mol) of hexamethylene diisocyanate and 3 to 4 drops of stannous octanate at a temperature of 60°C. After the mixture was refluxed for 1 hour, vacuum was applied to remove unreacted allyl alcohol. Then 0.2 mol of trimethylolpropane trithioglycolate was added. The resulting mixture was then divided equally and 3% by weight of triphenylsulfonium hexafluoroarsenate and 4-methoxydiphenyliodonium fluoroborate were added to each. The resulting curable mixture was then applied to an aluminum substrate and cured within 3-5 seconds at a distance of 6 inches using a Pyrex filter Hanovia 450W medium pressure arc lamp. Example 5 A mixture was prepared by combining 2 g of diethylene glycol divinyl ether with 1 g of pentaerythritol tetra-3-mercaptopropionate and 3% by weight of the resulting mixture of triphenylsulfonium hexafluoroantimonate. This mixture was then irradiated with ultraviolet light from a GEH3T7 medium pressure arc lamp at a distance of approximately 6 inches. After 5 seconds of irradiation, a 3 mil thick cured film was obtained. Example 6 66% by weight diallylisophthalate and 33% by weight
A sufficient amount of 4,4'-diisopropyliodonium hexafluoroarsenate is added to a mixture of pentaerythritol tetra-3-mercaptopropionate to form a photopolymerizable compound containing about 3% by weight of photoinitiator. A composition was produced. Then,
The photopolymerizable mixture was applied to a steel substrate to a thickness of about 3 mils and irradiated according to the method of Example 4 to produce a tack-free film within 20 seconds. Example 7 A sufficient amount of triphenylsulfonium hexafluoroarsenate was added to a mixture of pentaerythritol tetra-3-mercaptopropionate, 0.1 mole of bisphenol-A-diglycidyl ether, and the polyolefin formed by the reaction of diallylamine for about 2 hours. amount was added. The resulting curable mixture was applied as a 3 mil thick film to the surface of an aluminum substrate and then irradiated for 5 seconds. Irradiation was performed in the same manner as described above. A tack-free film suitable for insulating coatings or dielectric films for capacitors was obtained. Example 8 The method of Example 7 was repeated, except that 0.5% by weight of 2,6-di-tert-butyl-4-methylphenol was incorporated as a stabilizer in the mixture. Curing of the composition was again carried out within 5 seconds. This confirmed that the stabilizer did not interfere with the curing of the curable composition, and also showed that the curing mechanism was not a free radical mechanism. Those skilled in the art will appreciate that if the photoinitiator is a benzophenone or other free radical photoinitiator, such as that used in the aforementioned Kale et al. patent, the inhibitor will interfere with the rate of cure of the curable composition. You will recognize that. Although the above examples illustrate only a few of the large number of curable compositions that can be made according to the present invention, the curable compositions of the present invention have the general formula
It should be understood that the polymerization initiator of (1) can be prepared by blending the polyolefin of general formula (2) and the polythiol of general formula (3). Note that the present invention has the following embodiments. (1) An ultraviolet curable composition whose polyolefin component is diaryl phthalate. (2) An ultraviolet curable composition in which the polyolefin component is diallyl malate. (3) An ultraviolet curable composition in which the polyolefin component is triallyl cyanurate. (4) An ultraviolet curable composition in which the polythiol component is trimethylolpropane trithiol glycolate. (5) An ultraviolet curable composition in which the polythiol component is pentaerythritol tetra-3-mercaptopropionate. (6) An ultraviolet curable composition in which the photopolymerization initiator is triphenylsulfonium hexafluoroarsenate. (7) An ultraviolet curable composition in which the photopolymerization initiator is 4,4'-dimethyldiphenyliodonium hexafluorophosphate. (8) An ultraviolet curable composition in which the photopolymerization initiator is triphenylsulfonium tetrafluoroborate. (9) A method for treating a substrate, which comprises applying the ultraviolet curable composition according to the claims on the surface of the substrate and irradiating the treated substrate with ultraviolet rays.

Claims (1)

[Scope of Claims] 1 (A) A polyolefin component [A] -- [--D] x having the following general formula, where x is an integer having a value of at least 2, and A is a reactive olefin unsaturation. baseless,
A polyvalent organic group or an organosilicon group consisting of a chemically combined element selected from carbon, oxygen, nitrogen, phosphorus, silicon and mixtures thereof together with monovalent elements of chlorine, bromine, fluorine or hydrogen, and D is an olefinically unsaturated monovalent organic group) (B) A polythio component G(-SH)y having the following general formula (wherein: G is a polyvalent organic group without an aliphatic unsaturated group, y is at least (an integer having a value of 2) and (C) an ultraviolet curable composition containing 0.25 to 10% by weight of a photodegradable cationic photoinitiator of the following general formula (Y ⁺ ) _J (MF ₆ ) ^-(6-L) (In the formula, M is B, P,
One or more elements selected from the group consisting of As and Sb, Y ⁺ is [(R)a(R ¹ ) bI] ⁺ [(R)c(R ² )d(R ³ )eD] ⁺ [(R )f(R ⁴ )g(R ⁵ )hZ] ⁺ , in the formula; R is a monovalent aromatic organic group, R ¹ is a divalent aromatic organic group, R ² is alkyl, Cycloalkyl or substituted alkyl group, R ³ is a polyvalent organic group forming a heterocyclic or condensed ring structure selected from aliphatic groups and aromatic groups, R ⁴ is alkyl, alkoxy, cycloalkyl and substituted derivatives thereof a monovalent organic aliphatic group selected from R ⁵ is an aromatic heterocyclic group;
or a polyvalent organic group forming a fused ring structure,
D is an a-group element selected from sulfur, selenium, or tellurium; Z is an a-group element selected from nitrogen, phosphorus, arsenic, antimony, or bismuth; “a”
is an integer equal to 0 or 2, "b" is an integer equal to 0 or 1, the sum of a+b is equal to 2 or the valence of X, "c" is an integer equal to 0 or 3, "d" is an integer from 0 to 2 , "e" is an integer equal to 0 or 1, the sum of c+d+e is equal to 3 or the valence of D, "f" is an integer equal to 0 to 4, "g" is an integer equal to 0 to 2, " h” is 0
An integer of ~2, the sum of f + g + h is equal to 4 or the valence of Z, J = 6 - L L is the valence of M, an integer equal to 2 to 7,
An ultraviolet curable composition containing no free radical inhibitor, characterized in that it consists of: