FREE-RADICAL CURABLE COMPOSITIONS

Cross-Reference to Related Applications

This application is a Continuation-in-Part of U.S. Application Serial No. 404,578, filed September 8, 1989 which is a Continuation-in-Part of U.S. Application Serial No. 319,566 filed March 7, 1989

Technical Field

This invention is directed to free-radical curable compositions that are useful as coatings for various substrates. Background of the Invention There are many applications that require a rapidly curable coating composition that adheres to a substrate, is flexible, does not discolor and has low toxicity. For example, optical glass fibers are frequently coated with two superposed coatings. The coating that contacts the glass is a relatively soft, primary coating that must satisfactorily adhere to the fiber and be soft enough to resist microbending especially at low service temperatures. The outer, exposed coating is a much harder secondary coating that provides the desired resistance to handling forces yet must be flexible enough to enable the coated fiber to withstand repeated bending without cracking the coating. Other applications, e.g., optical fabrication, coatings for substrates including glass, metal, wood, plastic, rubber, paper, concrete, and fabrics, and adhesives also require compositions that are fast curing, have low toxicity and provide good physical properties.

Compositions that include low molecular weight (meth)acrylate diluents have been utilized for many of these applications. However, these (meth)acrylate diluents are hazardous to human health. Therefore, it

is desirable to eliminate or reduce the amount of low molecular weight (meth) crylate diluents present in a composition.

Vinyl ether compositions have been utilized as replacements for (meth)acrylates. Although vinyl ethers rapidly cure when exposed to ultraviolet light in the presence of a cationic curing catalyst, their cure under cationic conditions leaves catalyst residues that discolor the cured compositions and cause them to be sensitive to water. Furthermore, vinyl ether containing oligomers having relatively high equivalent weights, e.g., an equivalent weight in excess of about 500, do not cationically cure upon exposure to dosages of energy less than 3 Joules per square centimeter. Vinyl ethers do not homopoly erize in the presence of free-radical initiators. Therefore, vinyl ethers are not suitable replacements for (meth)acrylates.

Unsaturated polyesters, e.g., maleates and fumarates, are known to be substantially non-toxic, but are unsatisfactory as replacements for (meth)acrylates because their rate of cure when exposed to ultraviolet light is not satisfactory for certain applications. European Patent Application No. 0 322 808 published on 05.07.89 discloses a radiation curable composition that comprises an ethylenically unsaturated polyester component and a vinyl ether component having an average of at least two vinyl ether groups per molecule of the vinyl ether component. The unsaturated polyester component can be a polymer, oligomer or mixture thereof. Coatings produced from this composition are brittle and hard because of the large amount of electron deficient ethylenically unsaturated groups in the backbone of the polyester component which leads to short chain segments between cross-links. The vinyl ether component reacts with the unsaturated group

and results in a high degree of cross-linking that causes the cured composition to be brittle, inflexible and hard. Thus, coatings produced from the composition of this European Patent Application do not possess the needed flexibility and softness for applications, such as optical glass fiber coatings, that require a flexible and soft coating. Summary of the Invention

The invention is directed to free-radical curable compositions that comprise a (meth)acrylate oligomer; and at least one of a single functionality diluent, a mixture of single functionality diluents, and a dual functional monomer, wherein the ratio of electron-rich double bonds to electron deficient double bonds in the compositions is in the range of about 5:1 to about 1:5.

Optionally, the compositions of the present invention can further comprise at least one of a reactant having a saturated backbone and an average of at least one electron deficient ethylenically unsaturated end group per molecule of reactant and an oligomer having an average of at least one electron-rich ethylenically unsaturated group per molecule of oligomer. The electron deficient group of the reactant is preferably an ethylenically unsaturated dicarboxylate group. The electron-rich group of this oligomer is preferably a vinyl ether group.

The (meth)acrylate oligomer has a number average molecular weight of at least about 1000 daltons and preferably constitutes a minor amount of the composition.

The single functionality diluent has only one type of reactive group, e.g., an electron-rich ethylenically unsaturated group such as a preferred vinyl ether group or an electron deficient ethylenically

unsaturated group such as a preferred dicarboxylate group on the same molecule of diluent.

The dual functional monomer has at least one electron-rich ethylenically unsaturated group such as a vinyl ether group and at least one electron deficient ethylenically unsaturated group such as an unsaturated dicarboxylate group.

The saturated reactant is the reaction product of a polyester backbone containing component and/or a non-polyester backbone containing component and an electron deficient ethylenically unsaturated end group containing component.

The vinyl ether containing oligomer is the reaction product of a saturated backbone containing component and a vinyl ether having a hydroxyl group or an a ine group.

The compositions of the present invention are curable upon exposure to ionizing radiation, actinic energy and heat. The cured compositions exhibit good flexibility, tensile strength, percent elongation, toughness, abrasion resistance, tear resistance and adhesion to substrates. The (meth)acrylate oligomers are relatively inexpensive and their use can lower the cost of the compositions. Suitable uses for these compositions include optical glass fiber coatings, paper coatings, coatings for the metallization of non-metallic substrates, e.g. , plastics, coatings for rubber, metal, wood, concrete, leather, fabric and glass, optical fabrication, lamination of glass and other materials, i.e., composites, dentistry, proεthetics, adhesives, inks, flexigraphic printing plates, and the like.

Even when the oligomer containing the vinyl ether moiety has an equivalent weight in excess of about 500, compositions of the present invention that contain

the vinyl ether containing oligo ers are curable by a free-radical mechanism. Cationic curing of these oligomers is not practical.

Thus, the present invention provides compositions having many properties desired by industry while overcoming the shortcomings of the prior art. Detailed Description of Preferred Embodiments

The present invention is directed to free-radical curable compositions that comprise a (meth)acrylate oligomer and at least one of a single functionality diluent, a mixture of single functionality diluents and a dual functional monomer, wherein the ratio of electron-rich double bond to electron deficient double bonds in the compositions is in the range of about 5:1 to about 1:5.

The free-radical curable compositions of the present invention can further comprise at least one of a saturated reactant having a saturated backbone and an average of at least one electron deficient ethylenically unsaturated end group per molecule of saturated reactant and an oligomer having an average of at least one electron-rich ethylenically unsaturated group per molecule of oligomer. The electron deficient ethylenically unsaturated end group of the saturated reactant is preferably a dicarboxylate group. The electron-rich ethylenically unsaturated group of the oligomer having at least one electron-rich group is preferably a vinyl ether group.

The term " (meth)acrylate", and various grammatical forms thereof, identifies esters that are the reaction product of acrylic or methacrylic acid with a hydroxy group-containing compound.

The term "single functionality diluent", as used in its various grammatical forms, defines a diluent having only one type of reactive group, e.g. , an

electron-rich ethylenically unsaturated group such as a vinyl ether group or an electron deficient ethylenically unsaturated group such as a maleate on the same molecule of diluent. However, this diluent can be polyfunctional, i.e., a molecule can have more than one reactive group provided all reactive groups are of the same type. An admixture of single functionality diluents can have electron-rich groups and electron deficient groups. The single functionality diluent, including admixtures thereof, is preferably selected, i.e., both the type of reactive group(s) of the single functionality diluent(s) and the amount utilized are chosen, to provide in the composition a ratio of electron-rich double bonds to electron deficient double bonds of about 5:1 to about 1:5, preferably about 2:1 to about 1:2. Most preferably this ratio is about 1:1.

The term "dual functional monomer", as used herein, defines a monomer having at least one electron-rich ethylenically unsaturated group that preferably is a vinyl ether group and at least one electron deficient ethylenically unsaturated group that preferably is a dicarboxylate group. The ratio of electron-rich groups to electron deficient groups in the monomer can be selected to achieve the desired ratio of electron-rich double bonds to electron deficient double bonds in the composition.

The term "vinyl ether", in its various grammatical forms, refers to a vinyl group bound to an oxygen atom which is bound to a carbon atom.

The (meth)acrylate oligomers suitable for use in the present invention preferably contain an average of at least about 1.2, more preferably about 2 to about 4, (meth)acrylate groups per oligomer.

These (meth)acrylate oligomers are illustrated by Cargill 1570, a diacrylate ester of Bisphenol A epichlorohydrin epoxide resin having a number average molecular weight of about 700 daltons that is commercially available from Cargill, Carpentersville, IL.

The term "dalton", as used herein in its various grammatical forms, defines a unit of mass that is l/l2th the mass of carbon-12. The (meth)acrylate oligomer can be a poly(meth)acrylate of an epoxy functional resin. These poly(meth)acrylates preferably contain an average of more than about two (meth)acrylate groups per oligomer and are exemplified by the commercial product Novacure 3700 available from Interez, Inc., Louisville, KY, which is the dieεter of Epon 828 and acrylic acid. Epon 828 is an epoxy functional resin that is a diglycidyl ether of Bisphenol A that is commercially available from Shell Chemicals, New York, NY. The number average molecular weight of Novacure 3700 is about 500 daltons and of Epon 828 is about 390 daltons.

Diacrylate-modified polyurethanes are also useful as the (meth)acrylate oligomers, especially those that employ a polyester base. Particularly preferred are acrylate-capped polyurethanes that are the urethane reaction products of a hydroxy-functional polyester, especially one having an average of about 2 to about 5 hydroxy groups per molecule, with a monoacrylate monoisocyanate. These acrylate-capped polyurethanes are illustrated by a polyester made by reacting trimethylol propane with a caprolactone to a number average molecular weight of about 600 daltons followed by reaction with three molar proportions of the reaction product of 1 ol of 2-hydroxyethyl acrylate with 1 mol of isophorone diisocyanate. The end product is a

polyurethane triacrylate. The urethane-forming reaction is conventionally performed at about 60°C in the presence of about 1 percent by weight of dibutyltin dilaurate. A commercial, polyester-based polyacrylate- modified polyurethane that is useful herein is Uvithane 893 available from Thiokol Chemical Corp., Trenton, NJ. The polyester in the Uvithane 893 product is a polyester of adipic acid with about 1.2 molar proportions of ethylene glycol polyesterified to an acid number of less than about 5. This polyester is converted as described above to a polyacrylate-modified polyurethane that is a semi-solid at room temperature and that has an average unsaturation equivalent of about 0.15 to about 0.175 ethylenically unsaturated groups per 100 grams of resin. In polyester processing, the acid number, defined as the number of milligrams of base required to neutralize one gram of polyester, is used to monitor the progress of the reaction. The lower the acid number, the further the reaction has progressed. A polyacrylate-modified polyurethane that is suitable as the (meth)acrylate oligomer is the reaction product of 1 mol of diisocyanate, 1 mol of 2-hydroxyethyl acrylate (HEA) and about 1 weight percent dibutyltin dilaurate reacted at a temperature of about 40°C for a time period of 4 hours that is subsequently reacted at a temperature of about 60°C for a time period of about 2 hours with 1 mol of a commercial hydroxy end-functional caprolactone polyester. A suitable caprolactone polyester is the reaction product of 2 molε caprolactone and 1 mol of ethylene glycol reacted at a temperature of about 60°C for a time period of 4 hours. A suitable commercial caprolactone polyester is available from Union Carbide Corp., Danbury, CT, under the trade designation Tone M-100 which has a number average molecular weight of about 345 daltons.

The number average molecular weight of the (meth)acrylate oligomers is preferably about 1,000 to about 15,000, more preferably about 1,200 to about 6,000, daltons. The equivalent weight of the (meth)acrylate oligomers is preferably about 500 to about 5,000, more preferably about 600 to about 3,000.

The single functionality diluents suitable for use herein include vinyl ether diluents, vinyl amides, divinyl ethers, ethylenically unsaturated monocarboxylates and dicarboxylates that are not acrylates, the like and mixtures thereof.

Further representative of the single functionality diluents are N-vinyl pyrrolidinone, N-vinyl imidazole, 2-vinylpyridine, N-vinyl carbazole, N-vinyl caprolactam, the like, and mixtures thereof.

Representative of other single functionality diluents are the divinyl ethers of triethylene glycol or of any other diol, such as 1,6-hexane diol or dibutylene glycol. One may also use polyvinylates of other polyhydric alcohols, such as glycerin or trimethylol propane. Polyhydric polyethers can be used, such as ethylene oxide, propylene oxide or butylene oxide adductε of polyhydric alcohols, illustrated by ethylene glycol, butylene glycol, glycerin, trimethylol propane or pentaerythritol.

Preferred single functionality diluents are triethylene glycol divinyl ether commercially available from GAF under the trade designation Rapicure DVE-3, diethyl maleate, butane diol divinyl ether, 1,4-cyclo- hexane dimethanol divinyl ether, octyl vinyl ether, diethyl furmarate dimethyl maleate, the like, and mixtures thereof.

The single functionality diluents can have an average of about 1 to about , preferably about 1 to about 3, reactive groups per molecule.

The dual functional monomer can be represented by the following Formula I:

O 0

II 11

(I) R"-0-C-(Y)-C-R ^b -R ^c -0-CH=CH ₂

wherein R ^a is selected from the group conεiεting of H, C, to C ₁₀ alkyl or allyl groups, C ₅ to C ₁₀ aryl groups, metal ionε, heteroato s and combinations of carbon and heteroatoms; R ^b iε absent or selected from the group consisting of O, C(R ^a ) ₂ , heteroatoms or subεtituted heteroatomε; R ^c iε an aliphatic, branched or cyclic alkyl group or an arylalkyl group that containε 1 to about 10 carbon ato ε, and can contain heteroatoms; and Y iε εelected from the group conεiεting of:

9=C. ; CH, - C; C - CH _j and l!

CH, CH, CR ^d R ^d

wherein each R ^d iε independently selected from the group consiεting of H, C ₁ to C ₄ alkyl groupε, C ₅ to C ₁₀ aryl groupε and electron withdrawing groupε.

Preferably, R ^a iε a C, to C ₄ alkyl group, R ^b iε 0, R ^c iε a C ₂ to C ₈ alkyl group and each R ^d is H.

The heteroatoms that can be present in the dual functional monomer include non-carbon atomε εuch as oxygen, nitrogen, sulfur, εilicon, phoεphorus and the like.

Representative of electron withdrawing groupε are CN, S0 ₂ , S0 ₃ , C0NH ₂ , Cl, C0 ₂ and the like.

The saturated reactant is the reaction product of a polyester backbone containing component and/or a non-polyester backbone containing component and an electron deficient ethylenically unsaturated end group containing component.

The saturated polyester backbone containing component can be repreεented by hydroxy functional saturated dicarboxylates, polycarbonates, polycaprolactones and the like. Representative of the dicarboxylates are the reaction products of saturated polycarboxylic acids, or their anhydrides, and diols. Suitable saturated polycarboxylic acidε and anhydrideε include phthalic acid, isophthalic acid, terephthalic acid, trimetillitic acid, tetrahydrophthalic acid, hexahydrophthalic acid, tetrachlorophthalic acid, adipic acid, azelaic acid, sebacic acid, succinic acid, glutaric acid, malonic acid, pimelic acid, suberic acid, 2,2-dimethylsuccinic acid, 3,3-dimethylglutaric acid, 2,2-dimethylglutaric acid, the like, anhydrideε thereof, and mixtureε thereof. Suitable diolε include 1,4-butane diol, 1,8-octane diol and the like.

Representative of the saturated polycarbonates are polyhexamethylene carbonate commercially available from PPG Industries under the trade designation Duracarb 120 and polycyclohexane dimethylene carbonate commercially available from PPG Industries under the trade designation Duracarb 140.

Representative of the polycaprolactones are the Tone Polyol series of products, e.g., Tone 0200,

0221, 0301, 0310, 2201 and 2221, commercially available from Union Carbide, New York, NY. Tone Polyol 0200, 0221, 2201 and 2221 are difunctional. Tone Polyol 0301 and 0310 are trifunctional.

The saturated, non-polyester backbone containing component can be represented by hydroxy functional polyethers, Bisphenol-A alkoxylates, and siloxaneε and organic polyisocyanates, the like and mixtureε thereof. The group linking the ethylenically unsaturated group to the saturated non-polyester backbone (linking group) can be a urethane, urea, ether, or thio group and the like. The linking group can be an ester when the ethylenically unsaturated end group containing component iε a preferred dicarboxylate, dicarboxylic acid or dicarboxylic anhydride.

Repreεentative of the εaturated polyethers are polyalkylene oxides, alkyl εubεtituted poly(tetrahydrofuranε) , and copolymerε of the alkyl εubεtituted tetrahydrofuranε and a cyclic ether.

Repreεentative of the polyalkylene oxideε are poly(propylene oxide), commercially available from Union Carbide under the trade deεignation Niax PPG 1025 and poly(tetramethylene glycol), commercially available from DuPont under the trade deεignation Terathane 1000.

The alkyl substituted poly(tetrahydrofuranε) have ring structures that open during polymerization. The alkyl group of the alkyl substituted poly(tetrahydrofuranε) haε about 1 to about 4 carbon atomε. Representative of the alkyl εubεtituted poly(tetrahydrofuranε) are poly(2-methyltetrahydrofuran) and poly(3-methyltetrahydrofuran) . Repreεentative of the cyclic ethers with which the alkyl substituted tetrahydrofurans can be copolymerized are ethylene oxide, propylene oxide, tetrahydrofuran and the like.

Repreεentative of the Bisphenol-A alkoxylates are those wherein the alkoxy group contains about 2 to about 4 carbon atoms, e.g., ethoxy. A commercial Bisphenol-A alkoxylate is the Biεphenol-A diethyoxlate

available under the trade deεignation Dianol 22 from Akzo Research, The Netherlands.

Representative of the siloxanes is poly(dimethylsiloxane) commercially available from Dow Corning under the trade designation DC 193.

Any of a wide variety of organic polyisocyanates, alone or in admixture, can be utilized, diisocyanates alone or in admixture with one another preferably conεtituting all or almost all of this component. Representative diisocyanates include isophorone diisocyanate (IPDI) , toluene diisocyanate (TDI) , diphenylmethylene diisocyanate, hexamethylene diiεocyanate, cyclohexylene diiεocyanate, methylene dicyclohexane diiεocyanate, 2,2,4-trimethyl hexamethylene diisocyanate, m-phenylene diisocyanate, 4-chloro-l,3-phenylene diisocyanate, 4,4'-biphenylene diiεocyanate, 1,5-naphthalene diiεocyanate, 1,4-tetramethylene diiεocyanate, 1,6-hexamethylene diiεocyanate, 1,10-decamethylene diiεocyanate, l,4-cyclohexylene diiεocyanate, and polyalkyloxide and polyester glycol diisocyanateε such as polytetramethylene ether glycol terminated with TDI and polyethylenic adipate terminated with TDI, respectively. The polyester backbone containing component and/or the non-polyeεter backbone containing component are reacted with an ethylenically unsaturated group containing component that can be the reaction product of an ethylenically unsaturated dicarboxylic acid and a monohydric alcohol or an aforementioned cyclic ether. Representative unsaturated dicarboxylic acidε are maleic acid, aleic anhydride, fu aric acid, and itaconic acid.

Representative of the monohydric alcohols are the C, to C ₁₀ alcohols, e.g., ethanol, decanol, the like and mixtures thereof.

If the ester produced by the reaction of the dicarboxylic acid, or anhydride, and the alcohol, or cyclic ether, has unreacted carboxyl groupε, the ester can be conventionally reacted with a material having a group that is reactive with the carboxyl groups of the ester, e.g., hydroxy groups and epoxy groups. Preferably, this material iε reεinous and has a number average molecular weight of about 300 to about 5000, more preferably about 500 to about 3,500 daltons. The saturated reactant preferably has an average of about 1 to about 10, more preferably about 2 to about 5, electron deficient ethylenically unsaturated end groups per molecule of reactant.

The equivalent weight of the saturated reactant having electron deficient ethylenically unsaturated end groups is preferably about 100 to about 10,000, more preferably about 200 to about 1,000.

Oligomerε having an average of at leaεt one electron-rich ethylenically unεaturated end group per molecule of oligomer, preferably a vinyl ether containing oligomer, can be utilized in addition to, or in place of, the εaturated reactant in the compositions of the present invention.

The vinyl ether containing oligomer can be produced by conventionally reacting a monohydric or monoamine vinyl ether and a εaturated backbone moiety containing component. The backbone containing component iε repreεented by hydroxy functional polyeεterε, polycarbonates, siloxanes, polycaprolactoneε, Bisphenol-A alkoxylates, polyethers, and organic polyisocyanates, the like and mixtures thereof. The backbone of the vinyl ether containing oligomer can contain repeating backbone units. The group linking the vinyl ether group to the saturated backbone (linking group) can be a urethane, urea, ester, ether, or thio

group and the like. Preferred linking groupε are urethane, urea and ester groups. Mixtures of linking groups can be used.

Representative of the vinyl ethers suitable as reactants in the production of the vinyl ether containing oligomer are conventional vinyl ethers including triethylene glycol monovinyl ether and 1,4-cyclohexane dimethylol monovinyl ether.

Representative of the saturated polyesters, polyethers, polycaprolactones, Bisphenol-A alkoxylates, and siloxanes are those utilized in producing the saturated reactant.

The oligomers containing vinyl ether groupε can be the reaction product of an organic polyiεocyanate, preferably a diiεocyanate (eεpecially a diphenylalkane diiεocyanate in which the alkane group containε l to 8 carbon atomε) , and a tranεvinylated polyhydric alcohol mixture containing hydroxy groupε that iε the transvinylation reaction product of (1) at leaεt one vinyl ether and (2) at leaεt one polyhydric alcohol having an average of more than 2 hydroxy groupε per molecule. The polyiεocyanate iε preεent in an amount effective to consume subεtantially all of the available hydroxy groupε in the tranεvinylation mixture. The term "transvinylation", aε used in its variouε grammatical formε, means that the vinyl ether group of the vinyl ether and the hydroxy group of the alcohol are exchanged.

The terms "tranεvinylation mixture" and "tranεvinylation polyhydric alcohol mixture", aε used in their variouε grammatical formε, mean unreacted polyhydric alcohol, partially tranεvinylated polyhydric alcohol and fully tranεvinylated polyhydric alcohol are present in the transvinylation reaction product of the vinyl ether and the polyhydric alcohol. The

transvinylation mixture is preferably, but not necessarily, an equilibrium mixture.

The term "substantially all", in its various grammatical forms, when uεed in reference to the isocyanate consuming the hydroxy groups (hydroxy functionality) , means that if the vinyl ether containing oligomer has hydroxy groups, they are not present in an amount that adversely affects the properties of the compositionε. The tranεvinylated aliphatic polyhydric alcohol mixture can contain partially vinylated polyhydric alcoholε and at leaεt about 3 percent to about 90 percent by weight of unreacted polyhydric alcoholε. The polyiεocyanate conεumes substantially all of the available hydroxy functionality. Simple monohydric alcohols (which are formed when a C, to C ₄ alkyl vinyl ether is uεed) are preferably removed to provide a tranεvinylation mixture that iε εubεtantially free of εimple monohydric alcohol. Such an alcohol functions to terminate the vinyl ether containing oligomer which is formed, an action that is undeεirable, but tolerable in εome inεtanceε.

The term "simple monohydric alcohol", as uεed in itε variouε grammatical formε, referε to a short chain alcohol containing 1 to 4 carbon atoms and having only one hydroxy group per molecule.

The transvinylated mixture is produced by transvinylating a vinyl ether with at leaεt one polyhydric alcohol which preferably contains an average of more than 2 hydroxy groups per molecule, whereafter any simple monohydric alcohol by-product of the transvinylation reaction and the tranεvinylation catalyεt are normally removed. More particularly, the vinyl ether containing oligomerε are prepared from the transvinylation reaction product of an arylalkyl

polyhydric alcohol, which oεt preferably contains or consists of polyhydric alcohols having an average of 3 or more hydroxy groups per molecule, and a vinyl ether which can contain one or more vinyl ether groups per molecule. The transvinylated reaction product contains partially transvinylated polyhydric alcohols as well as unreacted polyhydric alcohols, and it can also contain fully transvinylated polyhydric alcohols.

The tranεvinylation reaction iε conveniently carried out in the presence of a catalyst that is known for use in this reaction. While it is not esεential, the catalyεt and the εimple monohydric alcohol by-productε of the reaction can both be optionally removed, and thiε uεually alεo removeε any unreacted monovinyl ether which may be present.

It is desired to point out that the catalyst is conventionally removed by filtration, which is a particularly εimple operation. Any εimple monohydric alcoholε and any unreacted monovinyl ether which can be preεent when a monovinyl ether iε uεed in the transvinylation reaction are highly volatile and easily removed by evaporation from the reaction product, leaving the balance of the tranεvinylation reaction product intact. Thiε method of operation eliminates the need to distill off the monohydric vinyl ether utilized in conventional compositions, and other components that are distilled off with this monohydric vinyl ether, from the potaεεium hydroxide catalyεt uεed in the reaction with acetylene. The distillation step utilized in the prior art is a difficult operation involving elevated temperature which causes undesired side reactions.

Filtration by a chro atography procedure iε a repreεentative method of removing the catalyst. In thiε procedure a 5 inch by 1.5 inch εilica gel column (70 to 230 U.S. Sieve Serieε mesh and having a pH neutral

surface) has a 0.5 inch layer of activated carbon placed thereon. The carbon is commercially available from Darco under the trade designation G-60 and passes through a 100 U.S. Sieve Series mesh. The column is wetted with triethylene glycol divinyl ether then the catalyst containing transvinylation mixture is poured through the column. The first 100 milliliters (ml) of eluent are discarded and the remaining eluent is collected as the transvinylation mixture. The catalyst utilized herein is a conventional transvinylation catalyst and is illustrated by the elements of Groupε IB, IIB, IVB, VB, VIB, VIIB, and VIII of the Periodic Table of Elementε. Repreεentative catalyεtε include palladium, mercury, copper, zinc, magneεium, cobalt, mercuric acetate, mercury (II) salts, lithium chloropalladite (I) dialkylpyridineε, phoεphateε of thallium, vanadium, chromium, manganese, iron; cobalt, nickel, Group VI oxyacid saltε and mixtureε thereof. A preεently preferred catalyεt iε palladium (II) .

The catalyεt uεed herein can be a finely divided powder and can be removed by filtration. The addition of charcoal to the tranεvinylation mixture can aεεist the filtration procesε, e.g., when a finely divided powder form of the catalyεt iε utilized. The εimple monohydric alcohol and any volatile alkyl monovinyl ether which iε preεent when an alkyl monovinyl ether iε used for tranεvinylation is preferably removed by vaporization, and this iε conveniently performed when methyl or ethyl vinyl etherε are uεed by applying a reduced pressure to the reaction product at room temperature, i.e., a temperature of about 20° to about 30°C. It is desired to restrict the purification operation to simple filtration, and this is done herein by using a polyvinyl ether, such aε a divinyl ether of a

diol illustrated by triethylene glycol divinyl ether, as a transvinylation reactant.

The catalyst can be bound to a εolid matrix such as charcoal, nickel, alumina, ion exchange resins, molecular sieves, zeolites, or similar materials. The εolid matrix having catalyεt bound thereto can be in the shape of beadε, filingε, part of the walls of a column, and the like. Alternatively, the solid matrix having catalyst bound thereto can be packed in a column. The product of the transvinylation reaction iε a mixture containing partially tranεvinylated polyhydric alcoholε. Accordingly, there is preεent on theεe partially tranεvinylated polyhydric moleculeε at least one vinyl ether group and at leaεt one hydroxy group, εo the tranεvinylation mixture tendε to deteriorate with time and expoεure to elevated temperature, at least partially by the formation of acetal groupε. Reaction with a polyiεocyanate in accordance with thiε invention εignificantly reduces the hydroxy content to minimize or largely avoid this deterioration. Prior to reaction with polyisocyanate, the preεent transvinylation mixture does not require an elevated temperature distillation operation. The elimination of thiε distillation operation further minimizes this deterioration of the transvinylation mixture.

The tranεvinylation mixture will normally contain some unreacted polyhydric alcoholε and εome fully vinylated polyvinyl alcoholε, aε previouεly indicated, and these are not removed. Thiε introduceε an important economy at the εame time that it enableε one to increase the molecular weight and the vinyl ether functionality by reaction of the transvinylation mixture with organic polyisocyanates. Increased molecular weight, the preεence of internal urethane or urea

groups, and the increased vinyl ether functionality all introduce physical toughness into the cured products.

In preferred practice, the partially transvinylated polyhydric alcoholε in this invention contain from 3 percent to 25 percent unreacted polyhydric alcohols, about 30 to about 94 percent partially transvinylated polyhydric alcohols, and from 3 percent to 25 percent fully transvinylated polyhydric alcohols. This is particularly preferred when the polyhydric alcohol that is transvinylated contains 3 or 4 hydroxy groupε.

The tranεvinylation reaction to produce vinyl etherε iε itεelf known, and illuεtrative articleε deεcribing thiε reaction uεing alkyl vinyl etherε are, McKeon et al, "The Palladium (II) Catalyzed Vinyl

Interchange Reaction - I", Tetrahedron 28:227-232 (1972) and McKeon et al., "The Palladium (II) Catalyzed Vinyl Interchange Reaction - II", Tetrahedron 28:233-238 (1972) . However, theεe articleε teach purifying the reaction product and do not suggest the use of a tranεvinylation mixture.

A method of synthesizing pure vinyl etherε iε diεcloεed in Smith et al., "A Facile Syntheεiε of Low and High Molecular Weight Divinyl Etherε of Poly(oxyethyrene) ", Polymer Preprints 28(2) :264-265 (August, 1987) . Smith teaches the εyntheεiε of pure vinyl etherε uεing tranεetherification che iεtry baεed on the palladium (II) catalyεtε of poly(oxyethylene) glycols and ethyl vinyl ether. While the tranεvinylation mixture can uεe a diol as the polyhydric alcohol, it preferably employs triols and tetrols (moεt preferably triolε) . Indeed, when diolε are uεed some higher functional polyol is preferably added to the mixture that is transvinylated or to the transvinylation mixture that is reacted with

the diisocyanate. Suitable higher functional polyols include the triols and higher hydroxy functional polyols referred to herein. Thus, the polyhydric alcohol can be a mixture of alcohols and has an average hydroxy functionality per molecule of more than 2.

Moreover, the transvinylation reaction formε unrefined tranεvinylation mixtureε which are further reacted to enhance stability of the tranεvinylation mixture by the formation of vinyl ether containing oligomers in which the molecular weight and vinyl ether functionality are both increased.

Suitable polyhydric alcohols for use in thiε transvinylation reaction can be arylalkyl or aliphatic polyhydric alcohols having an average of more than 2, preferably at least 3, hydroxy groups per molecule on the aliphatic or alkyl portion thereof. It is presently preferred that the polyhydric alcohols can have up to about an average of about 10 hydroxy groupε per molecule. The polyhydric alcohol utilized is preferably soluble in the vinyl ether and has a number average molecular weight of up to about 2,000 daltonε. We preferably employ polyhydric alcoholε that are liquid at room temperature, i.e., a temperature of about 20° to about 30° C. , or which (if εolid) have a number average molecular weight below about 400 daltonε.

The alkyl group of theεe arylalkyl polyhydric alcoholε preferably containε about 2 to about 10, more preferably about 3 to about 6, carbon atomε. The aryl group of theεe polyhydric alcohols preferably contains up to about 20, more preferably up to about 10, carbon atomε. Illustrative arylalkyl polyhydric alcohols include ethoxylated polyhydric phenols, hydroxy substituted ring structures, e.g., phenol, naphthol, and the like, that are alkoxylated, trimethylol benzene, and the like, and mixtures thereof.

Preferred polyhydric alcohols are aliphatic polyhydric alcohols that contain 2 to 10 carbon atoms, more preferably 3 to about 6 carbon atoms, and are illustrated by ethylene glycol, butylene glycol, ester diol, 1,6-hexane diol, glycerol, trimethylol propane, pentaerythritol, and sorbitol. Trimethylol propane iε particularly preferred.

The polyhydric alcohol can be a polyether, εuch aε the ethylene oxide or propylene oxide adductε of the polyhydric alcoholε noted previously. These are illuεtrated by the propylene oxide adduct of trimethylol propane that haε a number average molecular weight of about 1500 daltonε.

The polyhydric alcohol can. also be a saturated polyester of the polyhydric alcohols noted previously, εuch aε the reaction product of trimethylol propane with epεilon caprolactone having a number average molecular weight of about 600 and the reaction product of two mols of ethylene glycol with one mol of adipic acid. Still other polyhydric alcoholε are illustrated by resinous materials that contain hydroxy groupε, εuch aε εtyrene-allyl alcohol copolymerε, acrylic copolymers containing 2 percent to 20 percent of copolymerized 2-hydroxyethyl acrylate, and even starch or celluloεe. However, theεe have a higher hydroxy functionality than iε now preferred.

The polyhydric alcohol can also be amine subεtituted, e.g., triethanolamine.

It iε deεired to εtreεε that the reaction with acetylene utilized in the prior art iε not applicable to many of the polyhydric alcoholε which are particularly attractive for uεe in producing the present tranεvinylation mixture. Polyesters and polycarbonates, such as 1,6-hexane diol polycarbonate having a molecular weight of about 1,000 daltonε, are degraded by the

potassium hydroxide catalyst used in reaction with acetylene, but can be transvinylated in accordance with the present transvinylation process.

Suitable vinyl ethers can be represented by the following general Formula II:

wherein R ^e ,-R , R ⁹ , R ^h , and R ¹ are each independently selected from the group of hydrogen and lower alkyl groups containing 1 to 4 carbon atomε; R ^e , or R , and R ⁹ joined together can be part of a ring εtructure; R ^e , or R , and R ^h , or R ¹ , joined together can be part of a ring εtructure; and R ⁹ and R ^h , or R ^c , joined together can be part of a ring εtructure; R ^J is an aromatic or aliphatic group that is reactive only at the εite(s) where a vinyl ether containing radical iε bound; x iε 0 or 1; and n iε equal to 1 to 10, preferably 1 to 4, with the proviso that n is lesε than or equal to the number of reactive sites of R ^j .

R ¹ can contain heteroatomε, i.e., atomε other than carbon atomε, such aε oxygen, nitrogen, εulfur, silicon, phosphorus, and mixtures of heteroatoms alone or in combination with carbon atomε. R ^J can contain 1 to about 20, preferably 1 to about 10, atomε. R ^j iε preferably a straight or branched carbon containing group containing 1 to about 8, more preferably 1 to about 4, carbon atoms and can preferably contain oxygen atoms. Repreεentative of vinyl ethers of Formula II are dihydropyran and dimethylol benzene divinyl ether.

Preferred vinyl etherε for uεe in the tranεvinylation reaction can be represented by the following general Formula III:

(III) (CH ₂ = CH - O - CH ₂ - _n

wherein R ^k iε an aliphatic group that iε reactive only at the site(ε) where a vinyl ether containing radical iε bound and n iε equal to l to 4.

R containε at leaεt one carbon atom and can contain heteroatoms and mixtures of heteroatoms. Preferably, R ^k contains 1 to about 4 carbon atoms and can contain oxygen atomε. Vinyl ethers having the structure of Formula

III are illuεtrated by divinyl etherε, εuch aε 1,4-butane diol divinyl ether, 1,6-hexane diol divinyl ether, and triethylene glycol divinyl ether. Polyvinyl etherε of higher functionality are illuεtrated by trimethylol propane trivinyl ether and pentaerythritol tetravinyl ether.

Illustrative monovinyl ethers having the structure of Formula III are ethyl vinyl ether, methyl vinyl ether, n-butyl vinyl ether, and the like, including phenyl vinyl ether. The presently preferred monovinyl ether is ethyl vinyl ether which releases ethanol on reaction.

The equivalent ratio of the vinyl ether to the hydroxy groups in the polyhydric alcohol is in the range of about 0.5:1 to about 5:1, preferably 0.8:1 to 2:1.

Possibly of greater significance, the polyhydric alcohol is transvinylated to react with from 10 percent to 90 percent, preferably from 30 percent to 80 percent, of the hydroxy groupε which are present thereon. The higher the functionality of the polyhydric alcohol, the

higher the proportion of hydroxy groups thereon which should be reacted by transvinylation.

As previously discuεεed, a palladium (II) catalyst can be utilized. Illustrative palladium catalysts are PdCl ₂ , (PhCN) ₂ PdCl ₂ , diacetato- (2, '-bipyridyl)palladium (II), diacetato- (1,10-phenanthroline)palladium (II), diacetato- (N,N,N' ,N'-tetramethylenediamine)palladium (II) , diacetato(P,P,P' ,P'-tetraphenyl-1,2-di- phoεphino-ethane) palladium (II) , and the like.

Diacetato-(1,10-phenanthroline)-palladium (II) iε a preferred palladium (II) catalyεt.

The catalyεt iε uεually preεent in a range of about 0.001 to about 1 percent, preferably about 0.1 percent, by weight based on the total weight of the polyhydric alcohol and vinyl ether.

The transvinylation reaction iε a conventional one, aε previouεly indicated, and iε deεcribed in the articleε noted previously. We employ a closed vessel which is charged with the appropriate amounts of the polyhydric alcohol, vinyl ether and catalyst and the mixture iε εtirred and reacted at a temperature of from about room temperature up to about 45°C. The reaction proceedε slowly, and we usually permit it to proceed for an extended period of time up to about 3 days to obtain the desired equilibrium composition. After about 2 days we find that using a 20 percent εtoichiometric exceεs of vinyl ether with respect to hydroxy functionality cauεeε about half of the hydroxy groupe to be conεumed in the reaction.

A preferred method of performing the tranεvinylation reaction iε to utilize ultrasonic energy to enhance the transvinylation. In thiε method an admixture of the vinyl ether, the polyhydric alcohol and the catalyεt is exposed to ultrasonic energy for a time

period effective to produce the transvinylation mixture. The frequency of the ultrasonic energy is about 10 to about 850 kilohertz (kHz) . The ultrasonic transvinylation reaction is preferably performed at room temperature and pressure, i.e., about one atmosphere.

An illustrative device for supplying ultrasonic energy is a Model B220 ultrasonic cleaner, commercially available from Branson Corp. , Shelton, CT. Thiε cleaner haε 125 wattε of power and provideε a frequency of about 30 to about 50 kHz at thiε power level. In thiε method the reactantε are placed into a εuitable veεεel which iε then placed in the water bath of the cleaner. The cleaner iε then activated to enhance the tranεvinylation reaction. The tranεvinylation reaction can be run for a time period sufficient to obtain the desired tranεvinylation mixture. A method of determining if the deεired tranεvinylation mixture has been obtained iε to test εampleε by gaε chro atography to determine the content of the tranεvinylation mixture.

After the tranεvinylation reaction iε terminated, it iε convenient to remove the catalyεt by filtration, and the addition of about 1 percent by weight of charcoal can be helpful. We alεo prefer to strip off any volatile productε which can be preεent, and thiε can be done by εimply subjecting the reaction product to reduced pressure at room temperature. This removes any reεidual alkyl monovinyl ether and the simple monohydric alcohol by-product of the reaction, at least when methyl or ethyl vinyl ether is used. With higher monohydric alcohols, modeεt heat, i.e., heat to achieve a temperature of about 30 ^* to about 60 ^* C. , can be uεed to help remove volatiles. While the filtration step is preferably carried out prior to removal of volatiles, this sequence can be reversed. When

polyvinyl ethers are used, there is no need to subject the transvinylation reaction product to reduced presεure because there is no residual alkyl monovinyl ether or simple monohydric alcohol by-product present, and thiε is a feature of this invention.

It is preferred that the tranεvinylation polyhydric alcohol mixture be liquid at room temperature, but thiε is not esεential since reactive liquid materials can be added, e.g., the aforementioned vinyl etherε εuch aε ethyl vinyl ether or a polyvinyl ether εuch as ethylene glycol divinyl ether, to permit the further reactions contemplated herein to be carried out. Optionally, any residual alkyl monovinyl ether and simple monohydric alcohol by-product can be retained aε a reactive liquid material, but thiε iε uεually undeεirable since the monohydric alcohol is independently reactive with polyisocyanate and functionε aε a chain-terminating agent and limitε the attainment of the deεired molecular weight. Other conventional diluentε, e.g., N-vinyl pyrrolidone, N-vinyl caprolactam, and the like can alεo be present.

The unreacted polyhydric alcohol and partially transvinylated polyhydric alcohol are then converted into a vinyl ether containing oligomer by reaction with the diiεocyanate to form a vinyl ether containing oligomer preferably having an average of 1 to about 10, more preferably about 2 to about 5, vinyl ether groupε per molecule. The polyiεocyanate iε utilized in an amount εufficient to εubεtantially eliminate unreacted hydroxy groupε preεent in the tranεvinylation mixture. Therefore, the iεocyanate conεumes εubεtantially all of the available hydroxy groupε of the transvinylation mixture, i.e., lesε than about 0.1 percent by weight of hydroxy groupε are present in the vinyl ether containing

oligomer. Preferably the vinyl ester containing oligomer has a hydroxy number below about 10.

The reaction with organic polyisocyanates increaseε the number average molecular weight and the vinyl ether functionality of the reεultant vinyl ether containing oligomer. Thiε is especially true to the extent that polyhydric alcohols having a hydroxy functionality in excesε of 2 are uεed εince thiε introduceε branching or an increaεe in the number of vinyl ether or divinyl ether groupε. While the polyiεocyanate can have a functionality higher than two, it iε preferred to utilize diiεocyanteε becauεe of their availability and alεo becauεe thiε minimizeε the tendency to gel when εubεtantially all of the hydroxy functionality iε conεumed.

A εtoichiometric exceεε of iεocyanate groupε, baεed on hydroxy groupε, can be uεed, but a εtoichiometric proportion is preferred. Excesε iεocyanate groupε, when preεent, can be later conεumed by reaction with any iεocyanate reactive group. Thuε, one can poεt-react the exceεε iεocyanate groupε of the vinyl ether containing oligomer with an alcohol or amine-functional reagent that can be monofunctional or polyfunctional depending upon whether a further increaεe in molecular weight or functionality iε deεired.

The aforementioned polyiεocyanateε utilized in the production of the saturated reactant are suitable for use in producing the vinyl ether containing oligomers. In the reaction between hydroxy and isocyanate groups, it is preferred to employ a εtoichiometric balance between hydroxy and iεocyanate functionality and to maintain the reactants at an elevated reaction temperature of at least about 40°C. until the isocyanate functionality is subεtantially conεumed. Thiε also

indicateε the hydroxy functionality is similarly consumed. One can also use a small excesε of isocyanate functionality.

Since diisocyanates are preferably used herein, this means that the polyhydric alcohol uεed should contain a proportion of polyol having at least three hydroxy groups. Using a triol as illustrative, tranεvinylation provideε a monovinyl ether having two hydroxy groupε that is reacted with diisocyanateε to provide vinyl ether functionality along the length of the oligomer. Tranεvinylation alεo provides a monohydric divinyl ether which acts aε a capping agent. Such a capping agent supplies two vinyl ether groups wherever it appears in the vinyl ether containing oligomer. Both of theεe triol derivativeε increaεe the vinyl ether functionality of the vinyl ether containing oligomerε. Moreover, unreacted triol haε the εame function, for it provideε three brancheε which muεt be capped by the vinyl ether-containing capping agent. Further chain extenεion, and hence increaεed molecular weight, can be achieved by the addition of conventional chain extenders including amine functional chain extenders. Illustrative amine functional chain extenderε include polyoxyalkylene amineε and the Jeffamine line of products, commercially available from Jefferson Chemicals.

A monohydric capping agent can alεo be present to prevent gelation. The use, and amount required, of this agent is conventional. The internal urethane or urea groupε are provided by the εtoichiometry of the εyεtem. Subtracting the molar proportion of the monohydric capping agent, if such an agent is present, from the number of mols of diisocyanate, the equivalent ratio of hydroxy, and/or amine from the amine functional chain

extender if one is utilized, to isocyanate in the unreacted diisocyanate can be about 1:1 and can be up to about 1.2:1. This ratio increaseε the molecular weight of the vinyl ether containing oligomer and introduceε internal urethane or urea groupε therein.

Unreacted iεocyanate groups can be present in the vinyl ether containing oligomer, but are preferably minimized to lesε than about 0.1 percent by weight. More particularly, the residual isocyanate content of the vinyl ether containing oligomer obtained by reaction of the transvinylation mixture with polyisocyanate can be εubεtantial when further reaction, e.g. , reaction with an aforementioned amine functional chain extender, is contemplated, but when the vinyl ether containing oligomer is to be uεed for coating, it iε preferred that there be no detectable iεocyanate preεent.

The vinyl ether containing oligomerε can compriεe the reaction product of an organic diisocyanate with a transvinylation mixture containing hydroxy groupε that iε the tranεvinylation reaction product of a divinyl ether having the Formula III, above, and at leaεt one aliphatic polyhydric alcohol having an average of 3 or more hydroxy groupε per molecule. The diiεocyanate conεumeε εubεtantially all of the available hydroxy groupε of the tranεvinylation mixture. The equivalent ratio of vinyl ether to polyhydric alcohol iε in the range of about 0.5:1 to about 5:1.

Further exampleε of εuitable vinyl ether containing oligomerε are polyvinyl ether polyurethaneε and saturated polyesterε εuch aε thoεe shown in U.S. Patent Nos. 4,472,019, 4,749,807, 4,751,273, and 4,775,732.

Further representative vinyl ether containing oligomers are obtained by the metathesiε of a cyclic olefin ether having the following general Formula IV:

CR ^l =CR ^l (IV) I I

O—(CR ^l R ^l ) _m

wherein each R ^l independently can be hydrogen or an alkyl, aryl, cycloaliphatic or halogen group and m iε a number in the range of about 2 to about 10, preferably about 5 to about 6. Metatheεiε, which iε deεcribed in March, Advanced Organic Chemistry, Third Edition, copyright 1985 by John Wiley & Sonε, Inc., pp 1036-1039 & 1115, results in the opening of the ring of the cyclic olefin ether to produce an oligomer having the following general Formula V:

(V) Z f (CR ^l R ^l ) _m - O - CR ¹ - CR ¹ _ ^■ Z

wherein R ^l and m are aε previouεly deεcribed, y iε a number in the range of about 2 to about 50, preferably about 2 to about 25, and each Z iε a terminal group, e.g., hydrogen, a vinyl group. The vinyl ether containing oligomerε of Formula V can be blended with the other vinyl ether containing oligomerε of the preεent invention or thoεe diεcloεed in U.S. Patent Nos. 4,472,019; 4,749,807; 4,751,273; and 4,775,732.

The oligomers having an average of at leaεt one electron-rich ethylenically unεaturated group per molecule of oligomer preferably contain an average of about 1 to about 10, more preferably about 2 to about 5, electron-rich ethylenically unεaturated groups per molecule of oligomer.

The number average molecular weight of the oligomers having an average of at leaεt one electron- rich ethylenically unεaturated group per molecule of

oligomer is preferably about 500 to about 8,000, more preferably about 1,000 to about 4,000, daltons.

When the compoεitionε of the present invention are utilized as a primary coating for optical glass fiber the equivalent weight of the oligomers having an average of at least one electron-rich ethylenically unsaturated group per molecule of oligomer iε preferably about 500 to about 1,500, more preferably about 800 to about 1,200. When the compoεitionε of the preεent invention are utilized aε a secondary coating for optical glasε fiber the equivalent weight of the oligomerε having an average of at leaεt one electron-rich ethylenically unεaturated group per molecule of oligomer iε preferably about 300 to about 1,000, more preferably about 400 to about 800.

The present compositions preferably contain the (meth)acrylate oligomer in an amount in the range of about 1 to about 70, more preferably about 20 to about 40, weight percent based on the total weight of the composition.

The preεent compoεitionε preferably contain the εingle functionality diluent in an amount in the range of about 0 to about 40, more preferably about 5 to about 30, weight percent baεed on the total weight of the composition.

The preεent compoεitionε preferably contain the dual functional monomer in an amount in the range of about 0 to about 40, more preferably about 5 to about 30, weight percent baεed on the total weight of the composition.

The present compoεitionε preferably contain the εaturated reactant in an amount in the range of about 0 to about 60, more preferably about 30 to about

50, weight percent baεed on the total weight of the composition.

The present compositions preferably contain the vinyl ether containing oligomer in an amount in the range of about 0 to about 50, more preferably about 10 to about 30, weight percent baεed on the total weight of the composition.

The viscosity of the present co positionε iε preferably about 200 to about 100,000, more preferably about 500 to about 4,000, centipoiεe (cP) .

The compoεitionε of the preεent invention are preferably εolvent free.

The compoεitionε of the preεent invention can be cured upon expoεure to energy εuch aε ionizing radiation, actinic energy, i.e., ultraviolet and viεible light, and heat, i.e., thermal cure.

Conventional ionizing radiation sources include electron beam devices. The amount of ionizing radiation required for cure of a 3 mil thick film is about 1 to about 5 megaradε.

When cure of thiε co poεition by expoεure to actinic energy of appropriate wavelength, εuch aε ultraviolet light, a photoinitiator can be admixed with the compoεition. The photoinitiator iε preferably εelected from the group conεiεting of (1) hydroxy- or alkoxy-functional acetophenone derivativeε, preferably hydroxyalkyl phenoneε, and (2) benzoyl diaryl phoεphine oxideε. Materials having the two different types of ethylenically unsaturation, i.e., the vinyl ether group and the ethylenically unsaturated group, copolymerize rapidly in the presence of the specified groupε of photoinitiatorε to provide a rapid photocure and alεo interact rapidly upon exposure to other types of energy when no polymerization initiator is present.

Ethylenically unεaturated dicarboxylateε reεpond poorly to photocure uεing, for example, ultraviolet light when the photoinitiator is an ordinary aryl ketone photoinitiator, such as benzophenone. Also, the vinyl ethers do not exhibit any substantial curing reεponεe to ultraviolet light when theεe aryl ketone photoinitiatorε are utilized. Nonetheleεε, theεe two types of ethylenically unsaturated atoms in admixture respond to the photocure very rapidly when the photoinitiator is correctly εelected. The photocure, and the cure upon expoεure to other typeε of energy when no initiator iε preεent, iε eεpecially rapid and effective when both of the deεcribed typeε of unεaturation are provided in polyfunctional compounds, particularly thoεe of reεinouε character. The fastest cures are obtained when the respective functionalities are present in about the same equivalent amount.-

Preferred photoinitiatorε are (1) hydroxy- or alkoxy-functional acetophenone derivatives, more preferably hydroxyalkyl phenones, and (2) benzoyl diaryl phosphine oxideε.

The acetophenone derivatives that may be uεed have the Formula VI:

in which R ^m is an optional hydrocarbon εubstituent containing from 1 to 10 carbon atomε and which may be alkyl or aryl, e.g., methyl, ethyl, butyl, octyl or phenyl, X iε εelected from the group consisting of hydroxy, C, to C ₄ alkoxy, C, to C ₈ alkyl, cycloalkyl, halogen, and phenyl, or 2 Xs together are cycloalkyl,

and at least one X is εelected from the group consisting of hydroxy and C, to C _ύ alkoxy.

Many compounds have the required structure. The alkoxy groups are preferably methoxy or ethoxy, the alkyl group is preferably methyl or ethyl, the cycloalkyl group iε preferably cyclohexyl, and the halogen iε preferably chlorine. One commercially available compound iε the Ciba-Geigy product Irgacure 651 which haε the Formula VII:

Irgacure 184, alεo from Ciba-Geigy, iε another uεeful acetophenone derivative, and it haε the Formula VIII:

Still another commercially available uεeful acetophenone derivative is diethoxy acetophenone, available from Upjohn Chemicals, North Haven, CT, which haε the Formula IX:

When the photoinitiator iε a hydroxy-functional compound, one can define the uεeful acetophenone derivativeε in a somewhat different manner.

Thuε, the hydroxyalkyl phenoneε which are preferred herein have the Formula X:

in which R iε an alkylene group containing from 2-8 carbon atomε and R ⁿ iε an optional hydrocarbon subεtituent containing from 1 to 10 carbon atomε and which may be alkyl or aryl, e.g., methyl, ethyl, butyl, octyl or phenyl.

It is particularly preferred that the hydroxy group be in the 2-poεition in which caεe it iε preferably a tertiary hydroxy group which defineε a hydroxy group carried by a carbon atom that has its remaining three valences connected to other carbon atoms. Particularly preferred compounds have the Formula XI:

in which each R ^p iε independently an alkyl group containing from 1 to 4 carbon atomε. In the commercial product Darocur 1173 available from E-M Company, Hawthorne, N.Y., each R ^p iε methyl. Thiε provides a compound which can be described aε 2-hydroxy-2-methyl- 1-phenyl propane 1-one. The "propane" iε replaced by butane or hexane to deεcribe the correεponding compoundε, and theεe will further illuεtrate preferred compounds in thiε invention.

The benzoyl diaryl phoεphine oxide photoinitiatorε which may be uεed herein have the Formula XII:

In Formula XII, R ^q iε an optional hydrocarbon εubεtituent containing from 1 to 10 carbon atomε and may be alkyl or aryl aε previouεly noted, and each x iε independently an integer from 1 to 3. In preferred practice, a 2 ,4 ,6-trimethyl benzoyl compound iε uεed, and the two aromatic groupε connected to the phoεphorus atom are phenyl groups. This provides the compound 2, , 6-trimethyl benzoyl diphenyl phoεphine oxide which iε available from BASF under the trade deεignation Lucirin TPO.

When utilized, the photoinitiator iε preferably present in an amount in the range of about 0.01 to about 10.0, more preferably about 0.1 to about 6.0, weight percent baεed on the total weight of the compoεition.

Suitable εources of actinic energy includes lasers and other conventional light sourceε having an effective energy output, e.g., mercury lampε.

The wavelength of the actinic energy εuitable for uεe herein extendε from the ultraviolet range through the viεible light range and into the infrared range. Preferred wavelengthε are about 200 to about 2,000, more preferably about 250 to about 1,000, nanometers (nm) .

The amount of actinic energy utilized to solidify a 3 mil thick film is about 0.05 to about 5.0,

preferably about 0.1 to about l, Joules per square centimeter (J/sqcm) .

The compositions also can be thermally cured in the presence of a conventional thermal free-radical initiator, e.g. , benzoyl peroxide, cyclohexanone peroxide, N,N' azobis(isobutyrylnitrite) , metallic dryer systems, redox systems, and the like.

The uεe of (meth)acrylate oligomers and the single functionality diluent and/or the dual functional monomer in the compositionε of the present invention result in a reduction in toxicity as compared to conventional compositions that contain only (meth)acrylate oligomers and diluentε. The (meth)acrylate oligomerε result in improved physical properties, e.g., toughneεs, abrasion resiεtance, tear reεistance and flexibility in products produced from the compositions as compared to non (meth)acrylate containing compoεitionε. The reduction in toxicity and improved phyεical propertieε enhances the performance of the compositions of the present invention as coatingε for optical glaεε fibers, coatingε for substrates, e.g., glaεε, paper, wood, rubber, metal, concrete, fabric, and plaεtic, inks, flexigraphic printing plateε, binderε in the manufacturing of composites, and the like. The same results are achieved when the εaturated reactant and/or vinyl ether containing oligomer are preεent in the compositions. The use of the (meth)acrylate oligomerε in the compoεitionε of the present invention alεo lowerε the coεt of theεe compoεitionε aε compared to similar compositions that do not utilize the (meth)acrylate oligomers.

The following Examples are preeent by way of repreεentation, and not limitation, of the present invention.

- 39 -

EXAMPLE 1: Preparation of the Dual Functional Monomer Into a one liter 4-neck flask were introduced 298.3 grams (g) (1.732 equivalents) of diethylmaleate, commercially available from Aldrich Chemical Co., Milwaukee, WI, 201.2 g (1.732 equivalents) of

4-hydroxybutyl vinyl ether (HBVE) , commercially available from GAF under the trade designation Rapicure HBVE, 0.5 g of tetraoctyl titanate, a conventional esterification cataylst commercially available from DuPont under the trade designation TYZOR TOT, and 0.22 g of phenothiazine, a conventional inhibitor commercially available from ICI Chemicals, Wilmington, DE. The flask was fitted with a variable speed stirrer, thermometers, a snyder column, a condenser with a trap, a nitrogen sparge and a heating mantle.

The temperature of the contents of the flask and the temperature at the top of the column, i.e., a thermometer iε placed in the condenser at the top of the column to measure the temperature of distillate, were set to distill about 80 g of ethanol in a time period of about 2.5 hours. The resultant product was the dual functional monomer that had a viscosity at 25°C. of about 36 centipoise (cP) .

EXAMPLE 2: Compositionε of the Present Invention

Compositions were prepared and tested. Each composition comprised a (meth)acrylate oligomer and at least one of a single functionality diluent and a dual functional monomer of EXAMPLE 1. The formulations of the compositions are present in TABLE I.

TABLE I

Composit ons

Composition

Equivalent

Component wt. A 8 C D E τ G H I

Oligomer 1 60S 83.3 60.8 73.A ... ... ... ...

Oligomer2 2030 ... ... ... 92.4 81.9 82.9 ... ... ...

Oligomer 3 2829 ... ... ... ... 80.3 ... ...

Carg ll

15703 ⁴ I Jnreporte ... ... ... ... ... 75.0 75.0

DVE-3 ⁵ 101 13.8 10.1 16.3 4.6 8.2 4.1 2.9 8.0 2.5

Diethyl maleate 172 ... ... 6.9 —- 6.9 ... — 13.6 4.3

Monomer 243 ... 26.1 ... 9.9 13.8 ... 14.8

Photoinitiator 204 2.9 3.0 3.4 3.0 3.0 3.1 3.0 3.4 3.4

¹ The (meth)acrylate oligomer 1 of thiε Example. The (meth)acrylate oligomer 2 of thiε Example ³ The (meth)acrylate oligomer 3 of thiε Example. ^'

An acrylate oligomer that lε a diacrylate eεter of Biεphenol A epichlorohydrin epoxide reεin and iε commercially available from Cargill, Carpenterεville, IL. Triethyleneglycol divinyl ether commericially available from GAF under the trade deεignation Rapicure

DVE-3.

⁶ The dual functional monomer of EXAMPLE 1.

Irgacure 184, commercially available from Ciba-Geigy Corp. Ardεley, NY.

(Meth)acrylate oligomer 1 waε prepared by reacting 80.8 weight percent Adiprene L-200 commercially available from Uniroyal, Middlebury, CT, 0.1 weight percent of dibutyltin dilaurate, 0.1 weight percent butylated hydroxy toluene and 19 weight percent 2- hydroxyethyl acrylate.

(Meth)acrylate oligomer 2 was prepared by reacting 3 mols of IDPI and 3 mols of 2-hydroxyethyl acrylate which was then reacted with 1 mol of Jeffamine T5000, commercially available from Jefferson Chemicals. (Meth)acrylate oligomer 3 was prepared by reacting 18.65 weight percent Desmondur W, commercially available from Mobay Chemical Co., 0.01 weight percent P ₂ N, 0.03 weight percent butylated hydroxy toluene, 0.07 weight percent dibutyltin dilaurate and 35.9 weight percent NIAX PPG 1025 commercially available from Union Carbide which was then reacted with 4 weight percent hydroxyethyl acrylate which waε then reacted with 30 weight percent phenoxyethyl acrylate, 7.3 weight percent N-vinyl pyrrolidone and 4 weight percent Jeffamine D230 commercially available from Jefferεon Chemcialε.

The reεultε for teεtε conducted on Compoεitions A to I, and cured filmε prepared therefrom, are presented in TABLE II. The test procedureε are presented after TABLE II.

TABLE II Test Results

Property Composition: _A_ B C D E f

Appearance water yellow, water clear, clear, yellow, yellow, straw, yellow, white clear white very very very clear very clear slight slight slight slight haze haze haze haze

Viscosity (cP) 12,200 2100 9200 8750 2900 4700 5000 8500 19,100

Tensile Properties

Tensile (MPA) 9.4 13 10 2.3 2.0 2.5 6.2 32 37

Elongation (X) 48 34 49 75 51 53 71 3.3 3.0

Modulus (MPa) 25 61 24 3.7 3.6 4.9 7.7 933 1113

Water absorption (X) -2.8 -1.4 -2.5 -1.4 -3.6 -1.0 -0.5 ♦1.9

Uater extractables

(X) -4.8 -2.8 -4.7 -1.9 -4.1 -2.1 -2.7 -0.7 m

ND = Not determined.

The filmε, cured at a doεage of 1 Joule per εquare centimeter, prepared from Compositions A to I exhibited no odor. Films prepared from Compositionε A, B and C were clear and exhibited no tack and good adheεion and toughneεε. Filmε prepared from Compoεitionε D, E and F exhibited slight tack. Film prepared from Composition G exhibited εlight tack, good toughneεε and fair adheεion. Filmε prepared from Compoεitionε H and I exhibited no tack, were εtrong and stiff films. Appearance

The appearance of the liquid composition was determined visually. Viεcoεity

The viscosity, expresεed in centipoise (cP) , was measured using a Brookfield Model RVTD viscometer operated in accordance with the instructions provided

therewith. The temperature of each sample tested was

25°C.

Tensile Properties

A film for determination of the tensile properties, i.e., tensile strength [Megapascals (MPa)], percent elongation at break (%) and moduluε (MPa) , of the coating waε prepared by drawing down a 3 mil coating on glass plates using a Bird bar, commercially available from Pacific Scientific, Silver Springs, MD. An automatic draw down apparatus like a Gardner AG-3860 commercially available from Pacific Scientific, Gardner/Neotec Instrument Division, Silver Springε, MD, can be utilized. The coating waε cured using a "D" lamp from Fuεion Curing Syεte ε, Rockville, MD. The "D" lamp emitε radiation having a wavelength of about 200 to about 470 nanometerε with the peak radiation being at about 380 nanometerε and the power output thereof iε about 300 wattε per linear inch. The coating was cured at a doεe of about 1 J/εqcm which provided complete cure. The film waε then conditioned at 23 ± 2°C. and 50 + 3% relative humidity for a minimum time period of 16 hourε.

Six, 0.5 inch wide teεt specimens were cut from the film parallel to the direction of the draw down and removed from the glass plate. Triplicate measurementε of the dimensions of each specimen were taken and the average utilized. The tensile properties of these specimenε were then determined uεing an Inεtron Model 4201 from Instron Corp., Canton, MA operated in accordance with the instructionε provided therewith. Water Resistance

To determine the water resistance a 10 mil draw-down of the composition was made on a glasε plate utilizing a Bird bar. The composition was cured utilizing the "D" lamp at a dose of 1.0 J/sqcm. Three

test samples each having dimensions of 1/2" x 1" x 1/2" were cut from the cured coating. Each sample was weighed utilizing an analytical balance to obtain weight measurement A and then immersed in separate containers of deionized water. After a time period of 24 hours, the samples were removed from the water, blotted to remove excess water on the surface and reweighed to obtain weight measurement B. The samples were then placed in aluminum pans and maintained therein at ambient conditionε, i.e., ambient temperature (about 20° - 30°C.) and ambient humidity, for a time period of 120 hourε. The εa pleε were then reweighed to obtain weight meaεurement C. The following equationε were utilized to calculate the water abεorption and the extractableε. (I) % water abεorption = [ (B - A)/A] x 100

(II) % extractableε = [ (C - A)/A] x 100 It iε preferably to have relatively low % water abεorption and % extractableε.

A negative value obtained for % water abεorption indicateε water εoluble, low molecular weight materialε were leached out of the film.

EXAMPLE 3: Toxicity Studieε

Toxicity teεtε were performed on commercially available (meth)acrylate oligomerε and diluentε and on commercially available vinyl ether and maleate diluentε. The reεultε of theεe toxicity teεtε are provided in TABLE III.

TABLE III

Toxicity Tests

Inhalation Skin Eye

Oral LO 50 Skin DJQ Kill Irritation Irritation

Material (mq./kq.) (mq . /kq . ) (animals) (max.=8) (max.=10)

ACTOMER

X-70 ¹ 23.8 16 0 of 6

ACTOMER

X-80 ¹ 20 16 0 of 6

Neopentyl- glycol diacrylate 5.19 0.35 1 of 6

2-hydroxy- ethyl acrylate 0.65 0.14 1 of 6

Pentaery- thritol triβcrylate 2.46 0 of 6 10

2-phenoxyethyl acrylate 4.66 2.54 0 of 6

Diethylene- glycol diacrylate 0.77 0.18 0 of 6

1,6-hexanediol diacrylate 4.76 0.71 0 of 6

Triethylene- glycol divinyl ether 7500 72000 NA ^* 0.25

Dimethyl maleate 1410 530 NA 5.47 moderate

Diethyl maleate 3200 4000 NA mi ld mi ld

Dibutyl maleate 8530 16000 NA mi ld NA

¹ The Actomer products, commercially available from Union Carbide, are acrylate oligomers prepared by the addition of acrylic acid to epoxidized soy or linseed

oils. These are relatively high molecular weight materials containing up to three to six acrylic groups respectively per molecule.

² Neopentylglycol diacrylate was found to be an experimental tumor causing agent.

³ NA = Not available.

The skin irritation and eye irritation tests were conducted according to the procedure to catagorize the compositionε under the Federal Hazardous Substance Labeling Act (16 C.F.R. §1500).

A composition representing the present invention (Composition J) was tested for skin irritation and eye irritation. The teεt reεultε are preεented in TABLE IV, below.

TABLE IV Toxicity Study of Compoεitionε Composition Skin irritation (PI) ¹ Eve irritation J 1.8 non-irritant

¹ PI = Primary irritation index. A PI of 1.8 indicates the compoεition of the preεent invention (Compoεition J) iε only a mild irritant.

TABLE IV indicateε that the preεent compoεitionε reεult in a εignificant reduction in irritation aε compared to conventional (meth)acrylate compoεitionε. The reactant, a branched maleate terminated eεter, of Composition J waε prepared utilizing a glaεε flaεk equipped with a reflux condenser, Dean-Stark tube for azetropic separation of water, a heating mantle, a thermometer, and a mechanical εtirrer. A mixture of maleic anhydride (0.8 molε) and butyl carbitol (0.84

mols) was heated in the flask to 80*C. An exothermic reaction occurred and the temperature rose to 120*C. where it was held for a time period of 2 hours. Trimethylol propane (0.23 mols), 1,6-pentane diol (0.3 mols), azelaic acid (0.2 mols), Fascat 4100 a catalyst commercially available from M & T Chemical Co. (0.3%) and 40 ml of xylene were then added to the flask. The contents of the flask were heated and stirred while the water of reaction was removed by azetropic distillation. When an acid value of 16.5 waε reached, the xylene waε distilled out. The resulting branched maleate terminated ester had a Brookfield viεcoεity of 392 cP.

Composition J comprised Novacure 8805, a urethane acrylate oligomer commercially available from Interez Inc., Louisville, KY (40 parts), Rapicure DVE-3, commercially available from GAF (14.7 partε) , the maleate terminated eεter deεcribed above (55.9 partε), Darocur 1173, commercially available from E & M Company (5.0 parts), and Phenothiazine, commercially available from Eastman (0.2 parts) were blended together at room temperature under yellow εafety lightε until homogeneous. The resultant Composition J had a viscoεity of 1,830 cP, a weight per gallon of 8.6 poundε, and a cloεed cup flash point of greater than 212'F.

Composition J was drawn down on a paper sheet with a „ 20 wire wound rod, placed on a U.V. cure apparatus (commercially available from Fusion Syεte ε) to cure. At an expoεure of 1 Joule/square centimeter, the resultant coating waε completely cured (125+ MEK Double rubε) with a tough hard εurface. The same coating cured with 5 megaradε of electron beam expoεure. Removal of the Darocur 1173 from Compoεition J permitted much lower electron beam doεeε for total cure (about 2-3 megaradε) .

EXAMPLE 4: Comparison of Compoεitionε

A (meth)acrylate oligomer containing composition (Composition K) waε compared to a similar composition that did not include a (meth)acrylate oligomer (Composition L) . The formulations of Compositionε L and M are provided in TABLE V.

TABLE V

Compoεitionε

Component Compoεition (wt) : K

Novacure 8805 ¹ 36.2

Saturated

Reactant l ² 76.9

Saturated

Reactant 2 ³ 50.5

DVE-3 ⁴ 13.3 19.2

Photoinitiator ⁵ 5.0 3.9. Phenothiazine 0.2

¹ A urethane acrylate oligomer commercially available from Interez, Inc., Louiεville, KY.

² Saturated Reactant 1 of thiε EXAMPLE.

³ Saturated Reactant 2 of thiε EXAMPLE. ⁴ Triethyleneglycol divinyl ether commercially available from GAF under the trade deεignation Rapicure DVE-3. ⁵ Darocur 1173, commercially available from E-M Company, Hawthorne, NY.

Saturated Reactant 1 waε prepared by reacting the diiεocyanate commercially available under the trade deεignation Deεmodur W with the butyl celloεolve ester of maleic anhydride which had been reacted with propylene oxide.

Saturated Reactant 2 was prepared by reacting 1,5 pentane diol and maleic anhydride followed by reacting butyl carbitol therewith.

Properties of Compositionε L and M, and coatingε produced therefrom, were teεted and the results are provided in TABLE VI.

TABLE VI

Test Results

Property Composition: K L

Viscosity (cP) 1,830 3,500

MEK Double Rubs

Cure dose: 0.5 J/sqcm >200 175

1.0 J/sqcm >200 181

Adhesion to

Polycarbonate substrate (X) 0 0

Flexibility Stiff Stiff with slight flexibi lity

Flask point >212°F 163'F

Eye irritation non- non- irritant irritant

Skin irritation (PI) 1.8 2.3 (mild) (moderate)

The procedures for determining viscoεity, eye irritation and εkin irritation have been previouεly discussed.

The MEK Double Rubs teεt conεiεtε of curing a film of the composition at a cure dose of either 0.5 J/sqcm or 1 J/sqcm. The surface of the film was then rubbed with a cloth soaked in methyl ethyl ketone (MEK) . A section of the surface waε rubbed in one direction and then in the oppoεite direction over the εame section to constitute one double rub. The number provided is the number of the double rub at which deterioration of the film was first noted.

The adhesion to a polycarbonate substrate waε determined by curing a film of the composition on the substrate at a cure dose of 1 J/sqcm.

A first adhesion teεt waε conducted by making a cross hatching of 10 parallel cuts, equally spaced apart, in the film down to the substrate. Then, 10 parallel cuts, alεo equally spaced apart, were made perpendicular to the first 10 cutε. The cut section was then covered with Scotch brand 610 tape commercially available from 3M Company that adhered to the εurface. The tape waε removed and the number of squares of film remaining adhered to the subεtrate iε the percent adheεion. None of the film adhered to the substrate.

A second adhesion test was conducted but no cutε were made in the film. Again, none of the film remained adhered to the εubεtrate

The adhesion and flexibility of theεe compoεitionε can be improved by reducing the croεε-link denεity of the cured filmε. Thiε reduction can be achieved by increaεing the amount of εingle functionality diluent and/or dual functional monomer utilized.

EXAMPLE 5: Paper Coating Compoεitionε Compoεitionε εuitable aε paper coating compoεitionε were prepared and teεted. The formulationε of theεe compoεitionε are preεented in TABLE VII.

TABLE VII

Paper Coating Compositions

Component Composition (wt) N 0

Reactant 63.9 63.9 63.9

DVE-3 ² 23.0 23.0 23.0

Diethyl maleate 13.1 13.1 13.1

Photoinitiator 7.0 7.0 7.0

Phenothiazine 0.1 0.1 0.1

N-vinyl pyrrol <done 5.0 ... ...

DEA" 4.0 4.0 4.0

AM 1908" 10

DC 5T ⁶ 0.5 0.5 0.5

¹ The product of the reaction of trishydroxyethyl iεocyanurate with the butyl carbitol ester of maleic anhydride. ² Triethyleneglycol divinyl ether commercially available from GAF under the trade designation Rapicure DVE-3.

³ Darocur 1173, commercially available from E-M Company, Hawthorne, NY.

⁴ Diethyl amine. An acrylate-terminated mela ine derivative commercially available from Monsanto under the trade designation Santolink AM 1908.

⁶ A εurfactant available from Dow Corning.

The Compoεitions N to P, and filmε produced therefrom, were teεted. The teεt reεultε are provided in TABLE VIII.

TABLE VI 11

Test Results

Property Composition: ___ N 0

Viscosity (cP) 140 240 210

Adhesion to Paper Substrate:

610 100 100 100

610 Crosshatch 95 85 95

Scotch 100 95 100

MEK Double Rubs cure dose: 0.5 J/sqcm 64 100 69

1 J/sqcm 60 107 85

The teεt procedure for determination of the viscosity has been discuεsed previously

The adheεion to a paper εubεtrate tests was similar to the previously discuεεed adhesion test. The

cure dose for these adhesion test waε ₀ .5 J/sqcm. Furthermore, a third adhesion test was conducted using scotch tape on an uncross-hatched film.

The MEK Double Rubs test was conducted on a film cured to an aluminum Q panel.