CA1156795A - Curable fluorocarbon substituted polyetherurethaneacrylates - Google Patents

Abstract

Abstract of the Disclosure Radiation polymerizable polyetherurethane-acrylates having pendent fluorocarbon substituents are disclosed.
These novel compositions of matter may be radiation polymerized, e.g., by electron beam, actinic light or heat, to a light transmissive material. The fluorocarbon substituent of the disclosed polyetherurethane-acrylates generally have the formula -W-Rf, wherein W is a divalent connecting moiety and Rf is a highly fluorinated, preferably perfluorinated, aliphatic, aryl or alkaryl radical. These compositions have increased shelf life, may be utilized as 100% solids, and their time and extent of curing may be precisely controlled.
These novel radiation curable compositions are particularly useful for speciality application, such as in joining electro-optical components, and as a protective coatng.

Description

115~79~

This invention relates to compositions which are curable by radiation such as electron beam, actinic light or heat curable compositions. In one aspect, the present invention relates to polyetherurethaneacrylates. In a ~urther aspect, the present invention relates to substituted polyetherurethaneacrylates and to the cured compositions produced therefrom. In yet a further aspect, this invention relates to fluorocarbonpolyetherurethaneacrylates and to the radiation cured mat-erials produced therefrom.
The advantages of radiation curable (especially actinic light curable) polymers, such as the ability to precisely control the time and extent of cure, increased shelf life and the utili~ation of undiluted (i.e., 100%) solids, has motivated considerable research effort toward the development of these composi-tions. The present invention is a novel radiation curable composition that is particularly useful for specialty applications, such as in joining electro-opti-cal components, and as a protective coating.
In one aspect, the present invention provides a radiation curable com-position comprising a substituted urethane acrylate having an aliphatic backbone, said backbone having an ether or polyether group and having at least one pendent fluorinated organic group attached thereto, said pendent organic group having the formula -W-Rf wherein -W- is a connecting moiety selected from a single bond, -CH2-O-CH2, and -CH2OC-, and -Rf is a monovalent fluorinated organic radical hav-ing 35 to 85 weight percent fluorine, and at least 75 percent of its carbon val-ence bonds are attached to fluorine.
In a further aspect, the present invention provides radiation curable fluorocarbon-substituted polyetherurethaneacrylates having the formula:

l 156795 O O O

2 11 R[t0cH2-cH)mocNH-R -(NHC0-R -OCC-CH2) ]n III

R
wherein:
R is the residue or reaction product of a hydroxyl-containing material with an epoxy-containing material the hydroxyl-containing material having n hydroxyls;
n is an integer from 1 to 6 inclusively;
W is a polyvalent connecting moiety Rf is a monovalent highly fluorinated fluorocarbon radical;
m is a number having a value from 1 to about 20;
Rl is a polyvalent residue or reaction product of an organic polyisocyanate, Rl(NCO)p (preferably a cycloaliphatic or aromatic polyisocyanate) and a hydroxyl-containing material, p having a value of 2 20 to 4;
R2 is a divalent saturated aliphatic group havinq 2 to 6 carbon atoms and optionally one or two non-vicinal catenary oxygen atoms; and, R3 is hydrogen or methyl.
The fluorocarbon-substituted polyetherurethane-acrylates (hereafter sometimes referred to as fluorocarbon etheracrylates in the interest of brevity) of this 1 156~95 invention are curable (i.e., polymeriza~le) in the presence oE
catalysts or initiators which liberate or generate free-radicals under the influence of radiation such as actinic light or infrared radiation (heat). Free radicals can be generated in the system by the thermal or photo decompostion of known free radical initiators such as peroxides. Alternatively, the present materials have been found to be curable by the means of electron beam irradiation even in the complete absence of an initiator.
The cured materials of the invention can be utilized as tack-free protective coatings. Further, the cured compositions herein, having an optical transmission of greater than 95% and a low refractive index, are well suited for use as adhesives in ap-plications where optical transmissivity is required.
The fluorocarbon-substituted polyetherurethaneacrylates of this invention are generally prepared by procedures well known in the art. One synthetic route is as follows:
I. Preparation of a fluorocarbon-substituted polyether-alcohol (hereinafter sometimes designated fluorocarbonalcohol or fluorocarbonpolyoll.

A fluorocarbon-substituted (the substitution corresponding to -W-Rf in the final product) polyether-alcohol is prepared by ring opening additlon polymerization of a fluorocarbon-substituted epoxide with a hydroxyl containing compound (containing n hydroxyl group-~) initiator. This reaction may be written thus:

o R(OH)n + mn CH2-CH atalys R[(O-CH2-CH~mOH]n 7 w Rf Rf In I, Rf ls a pendent, monovalent, highly fluorinated aliphatic, aryl, or alkaryl radical. ~Pendent~
as the term is used herein means not of the backbone carbon chain, i.e., non-catenary. ~y ~highly fluorinated~
is meant that generally 35 to 85 weight percent, preferably 50-77 weight percent, of the fluorocarbon radical is fluorine, with at least 75 percent of the non-catenary carbon valence bonds being attached to fluorine atoms. The weight percent of fluorine in the preferably saturated pendent fluorocarbon radical is found by dividing the total atomic weight of the radical into the total atomic welght of the fluorine atoms present in the radicals (e.g., -CF3 is 82.6 weight percent fluorine).
Where Rf contains a plurality of carbon atoms in a 25 skeletal chain, such chain may be straight, branched or cyclic but preferably is straight. The skeletal chain of carbon atoms can be interrupted by divalent oxygen or 1 1~6795 trivalent nitrogen heteroatoms, each of which is bonded only to carbon atoms, but where such heteroatoms are present, it is preferable that the skeletal chain contain not more than one said heteroatom for every two carbon atoms. ~n occasional carbon-bonded hydrogen atom, bromine atom, or chlorine atom may be presentJ Where such atoms are present, they are preferably present to the extent of not more than one such atom for every two carbon atoms in the chain. Thus, the non-skeletal valence bonds are preferably carbon-to-fluorine bonds, that is, Rf is preferably perfluorinated. The total number of carbon atoms of Rf can Yary and can be, for example 1 to 18, preferably 1 to 12. Where Rf is or contains a cyclic structure, such structure preferably has S or 6 ring 15 member atoms, 1 or 2 of which can contain heteroatoms, e.g., oxygen and/or nitrogen. Where Rf is aryl, it has 1 or 2 rings. Where Rf is an aromatic structure, the aromatic structure may be substituted with lower alkyl radicals (i.e., alkyl radicals having 1-4 carbon atoms).

20 Examples of such aryl radicals include perfluorophenyl F F
F F

4-trifluoromethylphenyl, and perfluoronaphthyl. Rf is also preferably free of ethylenic or other carbon-to-carbon unsaturation, that is, it is a saturated 25 aliphatic or heterocyclic radical. Examples of useful Rf radicals are fluorinated alkyl, e.g., -CF3, -C8F17 and 1~6~95 alkoxyalkyl, e.g., CF30CF2-, said radicals being preferably perfluorinated straight-chain alkyl radicals, CnF2n+l, where n is 1 to 12.
In the above formula, W is a polyvalent connecting moiety. W has a valence of at least 2 and is preferably selected from the group consisting of carbon-to-carbon o single bonds, -CH2-0-CH2-, or -CH2-0-C-. The pendent group -W - Rf ls herein sometimes referred to as ~the pendent fluorocarbon substituent~, or the ~highly fluorinated fluorocarbon substituent~. This latter term is used especially when -W-~f and -Rf both are highly fluorinated.
In reaction I above, catalysts may be employed such as Lewis acids, optionally modified with organotin compounds. Generally, the reaction may be run without solvent at a temperature of about 25C to 150C. It is ~mportant to note at this juncture that the fluorocarbon substituent of the epoxide (-W-Rf ln I) becomes the pendent fluorocarbon-substituent of the novel polyetherurethaneacrylates of the invention. Hence, in this preparative route, the pendent fluorocarbon substituent of the end product is determined by the materials reacted in the first step.
II. Preparation of an isocyanate-term1nated fluorocarbon-substituted polyethe~.

ll56795 The product of Step I is reacted with an organic polyisocyanate Rl(NCO)p, p having a value of 2 to 4 according to the reaction:

o R[(O-CH2-CH)mOH]n ~ nRl~NCO)p--~ R[(O-CH2-CH)mOCNH-Rl-(NCO)p_l]n II
W W
Rf Rf Preparative Step II is generally discussed below.
III. Preparation of the fluorocarbonacrylates.
The novel fluorocarbon-substituted polyetherurethane-acrylates are prepared by reacting the product of Step II
wlth a hydroxyalkylacrylate according to the reaction:
O O
R~(OCH2-CH)mOCUH-Rl(UCO)p l]n ~ nHOR20CC=CH2 ~ ?

Rf O O O

R[(OCH2-CH)mOCNH-R -(NHCOR OCCI-CH2)p-l]n III
W R

Rf In the structural formulae of equations I, II
and III, R, Rf, Rl, R2, R3, m, n, p, and W are all defined as above.
In an alternative route, the fluorocarbonacrylates of the invention can be prepared by the reaction of a hydroxyalkylacrylate with an oryanic diisocyanate to form a polyisocyanatoalkylacrylate, viz., O O O

2 ~ 2 11 R (NCO)p+(p-l)HoR OC-C-CH2 OCN-R -(NHCOR OCf-CH2) IV
R
The product of I~ may then be reacted with a fluorocarbon-substituted polyetheralcohol such as the product of I above. Thiæ reaction may be written as follows:

R[(OCH2-CH)mOH]n + nOCN-RltNH3OR2O3C-CH2) W R
Rf V
O O O
~ 2 11 R[(OCH2-CH)mOCN-R ~NHCOR OC-C=CH2) ~n P

Rf All symbols are defined as above.
It is also contemplated and often desirable to 20 modify the fluorocarbon-substituted polyetheralcohols of Step I above, by copolymerizing the fluorocarbon epoxide with one or more oxacycloalkanes which may or may not have fluorine substituents, Oxacycloalkanes (cyclic ethers) herein comprise 25 cycloaliphatic hydrocarbons having at least one oxygen heteroatoms in the aliphatic ring. Oxacycloalkanes . 115~7g5 polymerize by ring opening to polyethers. Particularly useful oxacycloalkanes are the 2-, 3- and 4- carbon atom (which ln conjunction with an oxygen heteroatom form 3-, 4- and 5 member rings) species known as oxiranes, oxetanes and oxolanes. It has been found that the fluorocarbon-substitued polyether alcohols (Equation I) can be modified with up to about 80~ by weight oxacycloalkanes which contain no fluorine.
Selectively incorporating oxacycloalkanes in the fluoropolyetherurethaneacrylates provides a method to control the optical characteristics of the finished polymer. For example, decreasing the fluorine content of the polymer by increasing the amount of oxacycloalkane in the polyether chain, generally increases its refractive lS index.
Suitable hydroxyl-containing materials which can be used as initiators in step I preferably conta~n 1 to 6 hydroxyl groups and include water and monomeric or polymeric aliphatic alcohols having 1 to 18 or more carbon atoms. Examples of such aliphatic alcohols include methanol, ethanol, 2-chloroethanol, isopropanol, octanol-l, dodecanol, cyclohexanol, ethyleneglycol, propyleneglycol, 1,3-butanediol,

3,4-dibromo-1,4-butanediol, 1,4-butanediol, neopentylglycol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2-(2-hydroxyethoxy~ethanol, 2-[2-(hydroxyethoxy)ethoxy]ethanol, 2-1[2-[2-(hydroxy-ethoxy)ethoxy]ethoxy]]ethanol,3-(3-hydroxypropoxy)propanol, glycerol, trimethylolpropane, pentaerythritol, dipenta- erythritol, sorbitol, 1,1,4,4-tetrahydroperfluoro-tetramethyleneglycol, 1,1,5,5-tetrahydroperfluoropenta-methyleneglycol, and 1,1,6,6-tetrahydroperfluorohexa-methyleneglycol and the monomeric alcohols described in U.S. Patent 3,318,960. Preferred hydroxyl-containing materials for use as initiators are the short chain aliphatic terminal diols containing 4 to 6 methylene groups such as 1,6-hexanediol and 1-4 butanediol.
Suitable polymeric aliphatic alcohols for use in the present invention generally contain only carbon, hydrogen and oxygen and have 1 to 6 hydroxyl groups. The 15 hydroxyl groups may be primary or secondary and generally should be present to the extent of about one per thousand units of molecular weight (l.e., a hydroxy equivalent weight of less than 1000 is preferred). Polymeric aliphatlc alcohols having a hydroxyl equivalent weight of 20 greater than about 1000 generally produce polyetherurethaneacrylates having a ~luorine content which is too low to exhibit the advantageous properties of the present materials. Polymeric diols and triols having a molecular weight of less than about 2000 25 (corresponding to a hydroxyl equivalent weight of 670 and 1000 for triols and diols respectively) constitute a preferred class of polymeric aliphatic alcohols.

1 1~6795 Other useful polymeric aliphatic alcohols include polyester polyols, such as the lactone polyester~
described in U.S. Patent 3,169,945 (especially the polyesters terminated with two or more hydroxyl groups formed by reaction of epsilon-caprolactone and polyol), the hydroxyl-terminated polyester condensation polymers described in U.S. Patent 3,641,199, the substantially linear, saturated, hydroxyl-terminated polyesters described in U.S. Patent 3,457,326, the hydroxy-containing polyesters described in U.S. Patent 3,931,117, and the hydroxy- terminated block polymers of polyethers and polyesters described in U.S. Patent 3,960,572. Useful polyether block polymers include the hydroxy-terminated polyether condensation polymers described in U.S. Patent 3,641,199, the substantially linear, saturated hydroxy-terminated polyethers described in U.S. Patent 3,457,326, the polyalkylene ether polyols described in U.S. Patents 3,499,852, 3,697,485 and 3,711,444, and the polyetheylene glycol and polypropylene 20 glycols described in V.S. Patent 3,850,770. Useful polyolefin polyols include those described in U.S. Patent 3,678,014 and the ~ diols from ethylene described in J. Pol~mer Science, Part A-l, Vol. 5, p. 2693 (1967). A
particularly useful, commercially available class of 25 caprolactone polyols which can be used are those sold under the Trademark ~NIAX,- such as PCP-0200, PCP-0210, PCP-0230 and PCP-0300 (e.g., see technical bulletin 7~5 F42464 of Union Carbide Corp.).
Other useful hydroxyl-containing materials whlch can be utilized as initiators in I include polysiloxane polyols such as the hydroxy-terminated diorgano-polysiloxanes described in U.S. Patents

4,098,742 and 3,886,865, and the siloxanes having a reactive hydroxyl-functional group bonded to at least two of its silicon atoms, described in U.S. Patents 3,577,264, 3,976,676 and 4,013,698.
Suitable epoxide-containing compounds having pendent highly fluorinated fluorocarbon substituents (which become W-Rf in the finished polymer) are the fluoroaliphatic glycidyl ether compounds including perfluoroalkyl glycidyl ethers such as perfluoroisopropyl glycidyl ether whose preparation is described in U.S.
Patent 3,361,685; the 1,1, -trihydrofluoroalkyl glycidyl ethers such as the 1,1,3-trihydrotetrafluoroethyl glycidyl ether whose preparation is described in U.S.
Patent 3,417,035; the l,l-dihydroperfluoroalkyl glycidyl ethers such as l,l-dihydrotrifluoroethyl glycidyl ether, l,l-dihydropentafluoropropyl glycidyl ether, l,l-dihydroheptafluorobutyl glycidyl etherr l,l-dihydropentadecafluorooctyl glycidyl ether, l,l-dihydrohepadecafluorononyl glycidyl ether and others 25 whose preparation 1s described in U.S. Patent 3,591,547;
and the glycidyl perfluoroalkanoates such as glycidyl perfluoroacetate, glycidyl perfluoropropionate, glycidyl perfluorobutyrate, and glycidyl perfluorooctoate which are prepared by the esterification reaction of glycidol and the corresponding perfluoroalkanoic acids and the glycidyl ethers of fluorinated phenols such as perfluorophenyl glycldyl ether and trifluoromethylphenyl glycidyl ether.
Examples of oxaheterocycles that can be copolymerized with the fluorocarbon substituted epoxides for preparing the fluorocarbon alcohols and polyols lnclude ethylene oxide; alkyl-substituted ethylene oxides, e.g., propyleneoxide, epichlorohydrin, butyleneoxide alkenyl- substituted ethylene oxides, e.g., butenyloxide; aryl- substituted ethylene oxides, e.g., styreneoxide, benzylethylene oxlde; glycidyl ethers, e.g., methyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, 3-phenylpropyl glycidyl ether, cyclohexyl glycidyl ether; cycloalkyl oxides, e.gO, cyclohexene oxide, cyclopentene oxide and limonene oxide; oxetanes, e.g., oxetane and 2,2-dimethyl oxetane;
and the oxolanes, e.g., tetrahydrofuran. Other suitable copolymerizable epoxides and glycidyl ethers are disclosed in U.S. Patent 3,417,035 among others.
The preerred catalysts for preparing the fluorocarbon alcohols and polyols (I, above) are the catalyst systems comprising: (1) a fluorinated acld selected from bis(fluorinated aliphatic sulfonyl)alkanes, fluorinated aliphatic sulfonic acids, and Lewis acid of 1 15~7~5 the formula H X Fb+a where X may be aluminum, boron, phosphorus, arsenic, tin, antimony and the like; b is the highest oxidation number of X and a is 0 or 1; and (2) a polyvalent tin compound as are taught in assignee's copending Canadian application No. 326,143, entitled "Colorless Hydroxyl-terminated Poly(chloroalkylene ethers)", filed on April 23, 1979 clai~ing a U.S. priority date of May 17, 1978 in the name of Chung I. Young and Loren I. Barber, Jr. Many other catalysts are useful for preparing the fluorocarbon alcohols by cationic polymerization techniques. Useful Lewis acid 10 catalysts are disclosed in U.S. Patents 3,269,961; 3,850,856;
3,910,878; 3,910,879; and 3,980,579 among others. Useful aluminum alcoholate catalysts are disclosed in U.S. Patent 3,318,960 and the use of diethyl zinc to polymerize glycidyl ethers is disclosed in U.S. Patent 3,361,685.
The fluorocarbon alcohols are prepared in accordance with Equation I by adding one to 20 mole equivalents of fluorocarbon epoxy compound to one hydroxyl equivalent of hydroxyl-containing initiator compound. The temperature and time required for the reaction will vary depending on the particular reactants and amounts employed and on the nature and amount of catalyst used. Generally, temperatures from about 20C to 200C for periods up to 24 hours suffice for the reaction. The catalyst concentration for the pre-ferred fluorinated acid/organo tin compound can be from about ~ 14 -,A ~

I 1 ~ 6 7 9 ~

0.1% to about 1% of the total weight of reactants.
Generally, the higher the catalyst concentration, the lower the temperature and shorter the time required for the reaction. An inert organic solvent such as dichloromethane or chloroform may be employed to facilitate the reaction.
Polyisocyanates useful for preparing the fluorocarbon acrylates can be aliphatics, cycloaliphatic or aromatic, Exemplary diisocyanates are disclosed in U.S. Patents 3,641,199; 3,700,643; 3,960,572 and others.
Preferred polyisocyanates are the cycloaliphatic and aromatic diisocyanates of which isophorone diisocyanate and toluene diisocyanate ~tolylene-2,4-diisocyanate) are the most preferred.
An exemplary list of hydroxyalkylacrylates useful for preparing the polyetherurethaneacrylates is disclossd in U.S. Patent 3,577,252. Other desirable compounds include hydroxyalkylpolyacrylates such as trimetholylpropanediacrylate and pentaerythritoltriacrylate.
The reaction of the fluorocarbon alcohol, diisocyanate, and hydroxyalkylacrylate to form the polyetherurethaneacrylate in accordance with Equations II
and III or IV and V is performed in sequential steps at temperatures from about 20C to 100C for about 10 minutes to several hours,sufficient to bring about the reaction. Preferably, a tin catalyst such as diphenyl 1 15~'~9S

dibutyl tin dilaurate is used to promote the reaction~
Other sultable catalysts include compounds containing tertiary amino groups, and titanium compounds.
Generally, the catalyst is included to the extent of about 0.01 to about l.S percent of the total weight of reactants.
Depending on the use to which the fluorocarbon acrylates are to be put, various materials can be added including curing catalysts, fillers, extenders, pigments and dyes.
Generally, diluent monomers are added to fluorocarbon-substituted polyetherurethaneacrylates of the }nvention to reduce their viscosity and increase or decrease their curlng rate. Amounts of the diluent monomer up to 2 or more times the weight of the polyetherurethaneacrylate present may be employed. A

suitable diluent monomer is any ethylenically unsaturated monomer that is compatible and copolymerizable with the polyetherurethaneacrylates of the invention. Suitable ethylenically unsaturated monomers include acrylic acid, acrylates and acrylate esters such as methyl methacrylate, ethyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, styrene and its derivatlves such as, 2-chlorostyrene, 2,4-dichlorostyrene, acrylamide, 25 acrylonitrile, t-butyl acrylate, methyl acrylate, butyl acrylate, 2-(N-butylcarbamyl)ethyl methacrylate and 2-(N-ethylcarbamyl)ethyl methacrylate, N~vinyl-2-pyrrolidone. Especially desirable dilutent monomers are the acrylic acid and methacrylic acid esters of l,l-dihydroperfluoroalkanols such as 2,2,2-trifluoroethyl acrylate, l,l-dihydroperfluoropropyl methacrylate, l,l-dihydroperfluorobutyl acrylate and l,l-dihydroperfluorooctyl methacrylate. Other diluent monomers that can be incorporated into the composition of the invention to increase the cross-link density include 1,4-butylene dimethacrylate or acrylate, 1,1,6,6-tetrahydroperfluorohexanediol diacrylate, ethylene dimethacrylate, glyceryl diacrylate or methacrylate, glyceryl triacrylate or trimethacrylate, pentaerythritol triacrylate or trimethacrylate, diallyl phthalate, dipentaerythritol pentaacrylate, neopentylglycol triacrylate and 1,3,5-tri(2-methacryloxyethyl)-s-triazine.
Suitable catalysts or initiators for use in polymerizing (curing) the compositions of the invention are catalysts which liberate or generate free-radicals upon addition of energy in the form of radiation such as heat, actinic light or electron beam. Such catalysts are well known and are described frequently in the polymerization art, e.g., Chapter II of ~Photochemistry~
by Calvert and Pitts~ John Wiley & Sons (1966).
Included among free radical catalysts are the conventional heat activated catalysts such as organic peroxides and organic hydroperoxides; examples are 115~7~5 benzoyl peroxide, tertiary-butyl perbenzoate, cumene hydroperoxide, azobis(isobutyronitrile) and the like~
The preferred catalysts ara photopolymerization initiators which facilitate polymerization when the composition is irradiated. Included among such initiators are acyloin and derlvatives thereof, such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and ~-methylbenzoin; diketones such as benzil and diacetyl, etc.; organic sulfides such as diphenyl monosulfide, diphenyl disulfide, decyl phenyl sulfide, and tetramethylthiuram monosulfide; S-acyl dithiocarbamates, such as S-benzoyl-N,N-dimethyldithiocarbamate; phenones such as acetophenone, a,a,~-tribromacetophenone, 15 a, a-d i ethoxyacetophenone, o-nitro-~ -tribromoacetophenone; benzophenone, and p,p'-tetramethyldiaminobenzophenone; sulfonyl halides such as p-toluenesulfonyl chloride, l-naphthalenesulfonyl chloride, 2-naphthalenesulfonyl chloride, 1,3-benzenedisulfonyl chloride, 2,4-dinitrobenzene-sulfonyl bromide and p-acetamidobenzenesulfonyl chloride. Normally, the initiator is used in amounts ranging from about 0.01 to 5% by weight of the total polymerizable composition. When the quantity is less than 0.01% by weight, the polymerization rate becomes extremely low~ If the initiator is used in excess of about 5% by weight, no correspondingly improved effect ' ~1567g~

can be expected. Preferably, about 0.25 to 1.0~ by weight of initiator is used in the polymerizable compositions. As noted above, a catalyst is not necessary when cure of the present materials is undertaken by such curing techniques as electron beam.
The advantages and benefits of the compositions o the invention will be described in the following illustrative examples wherein the term aparts~ refers to parts by weight unless otherwise indicated. In the examples, the polyetherpolyols having pendent fluorocarbon groups were prepared according to the following general procedure.
The fluorocarbon alcohols were prepared in glas~ reactlon flasks equipped with a stirrer, thermometer and a dropping funnel. A dry atmosphere was maintained within the flask during the reaction.
In each preparation, the hydroxyl-containing material (generally, about 0.1 mole) and 0.3 weight percent of a catalyst system of both bis(trifluoromethylsulfonyl) phenylmethane, (CF3~02)2cHc6H5~ and dibutyldiphenyltinJ
(C6Hs)2(C4Hg)2Sn, were charged into the flask and heated to 80C while stirring. The fluorocarbon epoxide and, where used, a copolymerizable oxacycloalkane (e.g., non-fluorine- containing oxira~e, oxetane or oxolane) were then charged dropwise over a period of 0.5 to 1 hour to the stirred and heated flask. The resulting mixture 1 15~J,795 was stirred at atmospheric pressure at 50C to 125C
until the reaction was substantially complete, generally 8 to 24 hours. Then the reacted compositions were heated at about 80C under about 0.5 Torr for a period of time sufficient to remove volatile components. The ratio of the moles of initiator hydroxyl compound to the moles of fluorocarbon epoxide and oxacycloalkane (where used) was varied to control the hydroxyl equivalent of the product fluorocarbon alcohol.

In accordance with the general procedures given above, various fluorocarbon alcohols were prepared.
The initiator alcohol, fluorocarbon epoxide, mole ratio of alcohol to epoxide, reaction temperature and ratio of moles of bis(trifluoromethylsulfonyl)phenylmethane (commercially referred to as phenyl disulfone, or 0DS) to moles of dibutyldiphenyltin in the catalyst system are given in Table I. Also given are the percent of epoxide convers1On, the hydroxyl equivalent weight, the polydispersity (p= the ratio of weight average to number average molecular weight), and the values of m and n in the general formula of the product alcohol. Also given in Table I are the glass transition temperature, Tg, the melting point, Tm~ and the refractive index of the product fluorocarbon alcohol.
The polydispersity was determined by gel permea-tion chromatography using a Waters, Associates 1 1~67~S

chromatograph with a microstyrogel column. The hydroxy equivalent weights were obtained by reacting the hydroxyl group with phenylisocyanate, adding amine to remove the excess phenyl isocyanate and titrating the excess amine with dilute hydrochloric acid. The value of m was found by calculation from the hydroxyl equivalent weight. The Tg and Tm were measured using differential thermal analysis (using the 900 DTA differential thermal-analyzer and instructions available from the E.I. duPont deNemours and Company). The refractive indices were determined on a Rarl Zeiss refractometer.

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115~3795 The following additional examples illustrate the preparation of the fluorocarbon substituted polyetherurethane acrylates of the invention.

Thirty grams of the fluorocarbon polyol of Example 2 was mixed wlth one equivalent (7.50 g) of distilled isophorone diisocyanate until thoroughly blended. The mixture was roll milled until the infrared spectrum of the mixture no longer exhibited an absorption peak at 3.10 micrometers attributable to hydroxyl functionality (about two hours). One equivalent (4.40 g) distilled 2-hydroxyethyl methacrylate was then added to the mixture and roll milling continued until the infrared spectrum no longer exhibited an absorption peak at 4.2 mlcrometers attributable to isocyanate funct~onality, but exhibited a peak at 5.84 micrometers attributable to urethane functionality (about two hours). The fluorocarbonetheracrylate obtained was a clear, very viscous oil having a structure that was essent1ally:

~CH2~6 [~0CH2CH ) 20CNH~CH3 CIH2~ ~H3 e e OH3C CH2-NHCO~CH2)2OCC=CH2]2 2 7 15C~3 To ten parts of the fluorocarbon etheracrylate obta~ned above was added and thoroughly mixed one part by weight of l,l-dihydroperfluorooctyl methacrylate to reduce the viscosity of the mixture and 0.01 part of diethoxy-acetophenone as actinlc light or photoinitiator. The mixture was cast as a 140 micrometer thick layer between two sheets of 50 micrometer polyester. Upon exposure to the radiation from a xenon/mercury arc lamp, the layer cured within one mlnute to a tough, flexible, clear film having a refractive index of 1.402, a tensile strength of 85.4 kg/cm2 (1200 p5i) ~ and an elongation at break of 9.4%.

The procedure of Example 22 was followed with the exception that different fluorocarbon polyols from Table 1 were employed. The results of these further runs are summarized in Table 2. Isophorone diisocyanate, 2-hydroxyethylmethacrylate, and diethoxyacetophenone photoinitiator were employed as in Example 22.

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o a),t ~ _, ~,, ~ ~1 a ~i ~q ~ s :)dP .C L ~~ ~ ~P .C h J.) o ~ ~ ~ o ~ ~ a~ o-- a C

O
a ~ ~q O
O ~1 ~ O O~
O >
:~ ~1 r~ ~ X X X

~1 x ~ ~ ~r u~
;

115~795 2~-The procedure of Example 22 was followed with the exception that the preparation of the highly fluorinated fluorocarbon substituted polyetherurethaneacrylate was accomplished by heating the reaction mixture with an infrared lamp on a roll mill.
The results of these runs are summarized ln ~able III.

-2(`

C
.~
~ ~:
~ O ~
o D
P. ~

H V ~
~ O ~ ~ ~ ~ In o i~ 1 ~ ~ x ~ a~ ~ ~
~ ~n i ~g~
-~ ~ ~ V ~ ~3 V
~1 ~ ~1 ?
~1 E ~ ~~ ~ ~ ~ s~
.8~
O-~ ~ ~, CO ~
~1 ~ L~

~ ~ ~ ~ ~ ~

'7~

A fluorocarbonpolyeth~erurethaneacrylate was prepared by mixing on a roller mill for about two hours a mixture of 20 part~ of the fluorocarbon diol of Example 2 and 3.19 parts of isocyanatoethyl methacrylate (available from Dow Chemical Company). The resultlng compound had an infrared absorption peak at 5.84 micrometers attributable to urethane functionality. A cured film prepared wlthout addition of diluent monomer had a refractive index of 1 388, a tensile strength of 60 kg~cm2 (850 psi) and an elongation at break of 2~

Ten parts of fluorocarbonetheracrylate as described ~n Example 2 was diluted with 3 parts by weight of l,l-dihydroperfluorooctyl methacrylate and polymerized as a film that had an index of refraction of 1.408, a tensile strength of 133 kg/cm2 (1900 psi) and an elongation at break of 36%.

When ten parts of fluorocarbonetheracrylate as described in Example 22 were diluted with five parts by weight of l,l-dihydroperfluorooctyl methacrylate and polymerized, a film was obtained having an index of fraction of 1.397, a tensile strength of 78.4 kg/cm2 (1120 psi) and an elongation at break of 82~.

i7~

The fluorocarbonetheracrylate prepared in Example 22 was diluted with 10% by weight of the acrylate ester rather than the methacrylate ester of l,l-dihydro~
perfluorooctyl alcohol and cast as a 140 micrometers thick film between two sheets of polyester film. The cured film obtalned had a refractive index at 25C of 1.413, a tenslle strength of 78.4 kg/cm2 (1120 psi) and an elcngation at break of 29~.

The procedure of Example 22 was followed with the exception that an equivalent weight of tolylene-2~4-diisocyanate was used in place of isophoronedilsocyanate.
The fluorocarbonetheracrylate obtained had an infrared spectrum consistent with a structure that was essentially:
O O O
Il 11 11 tCH2t6[tOCH2CH ~ OCNH ~ NHC(CH2)2CC=CH2 o On polymerIzation of the fluorocarbonether-acrylate without use of a diluent monomer, a cured film having a refractive index at 25C of 1.408, a tensile strength of 65 kg/cm2 (928 psi), and an elongation at break of 42~ was obtained.

115~

Example 35 ~ rapidly photocuring system comprislng fluorocarbonetheracrylates was formulated by mxing 4 grams of the fluorocarbonetheracrylate as described in Exampla 2 with 2 grams of l,l-dihydroxyperfluoro-octylacrylate, 2 gram~ of 1,6-tetrahydroperfluoro hexanediol diacrylate, 0.8 gram N-vinyl-2-pyrrolidone and 0.5 gram diethoxyacetophenone. This formulation was coated onto poly(vinylchloride~ film. Vpon exposure in air to ultravlolet radiation of 1 joule/cm2 from two 200-watt medium pressure Hanovia mercury lamps, the formulation cured in 0.5 second to form a clear tough coating.

Example 37 A sample of the fluorocarbonetheracrylate system described in Example 22 was coated onto a sheet of 2 mil(50 micrometer) polyester film using a ~14 wire-~ound bar. A thin sheet of 0.5 mll polyimide was rolled over the coating with a printing rollerO The sample was irradiated in an electron beam at 1.05 KV and 2.5 milliamps for 8 seconds. The coating was completely cured after this exposure.

Example 3~
A l-gram sample of the fluoroca~bonetheracrylate system described in Example 22 was mixed with 25 mg AIBN
~azobisisobutyronitrile) with gentle heating until the 7~5 initiator was dissolved. A 5.4-mll (140-mlcrometer) coating was cast between two layers of 2-mil (50-micrometer) polyester. The sample was cured at 65C
for 15 hours, after which time the sample was cured.

Claims (21)

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

1. A radiation curable composition comprising a substituted urethane acrylate having an aliphatic backbone, said backbone having an ether or polyether group and having at least one pendent fluorinated organic group attached thereto, said pendant organic group having the formula -W-Rf wherein -W- is a connecting moiety selected from a single bond, -CH2-O-CH2, and , and -Rf is a movalent fluorinated organic radical having 35 to 85 weight per-cent fluorine, and at least 75 percent of its carbon valence bonds are attached to fluorine.

2. The composition according to claim 1 wherein -Rf contains 50 to 77 weight percent of fluorine.

3. The composition of claim 1 further comprising a sufficient quantity of an actinic light activatable free radical polymeriza-tion initiator to cause polymerization of said composition by actinic light.

4. The composition according to claim 4 wherein said pendent organic group is perfluorinated.

5. The composition according to claim 4 which further com-prises an oxycycloalkane.

6. A class of substituted urethane acrylates and methacry-lates having an aliphatic backbone, the members of the class having at least one ether or polyether group with at least one pendent fluorinated organic group attached thereto, said urethane acrylate having the formula:

wherein:
R is the residue or reaction product of a hydroxyl-containing material having n hydroxyls the hydroxyl-containing material having been reacted with an epoxy-containing material;
n is an integer from 1 to 6 inclusively;
W is a polyvalent connecting moiety selected from a single bond, -CH2-O-CH2, and Rf is a monovalent fluorinated, organic group;
m is a number having a value from 1 to about 20;
R1 is a polyvalent residue or reaction product of an organic polyisocyanate, R1(NCO)p and a hydroxyl-containing material, p having a value of 2 to 4;
R2 is a divalent saturated aliphatic group having 2 to 6 carbon atoms and optionally one or two non-vicinal catenary oxygen atoms; and, R3 is hydrogen or methyl.

7. A composition according to claim 6 whieh further includes an actinic light activatable free-radical polymerization initiator.

8. The composition aecording to claim 7 wherein said initiator comprises diethoxyaeetophenone.

9. The composition according to claim 6 wherein said composition is radiation curable.

10. The composition according to claim 6 wherein said pendent organic group is perfluorinated.

11. A composition according to claim 6 wherein said hydroxyl containing material comprising aliphatic alcohols having 1 to 18 carbon atoms and 1 to 6 hydroxyl groups.

12. A composition according to claim 11 wherein said alcohols are 1,6-hexanediol and 1,4-butanediol.

13. A composition according to claim 6 wherein said organic polyioscyanate is cycloaliphatic.

14. A composition according to claim 13 wherein said polyisocyanate is isophorone diisocyanate.

15. A composition according to claim 6 wherein said organic polyioscyanate is aromatic.

16. A composition according to claim 15 wherein the polyisocyanate is toluene diisocyanate.

17. A composition according to claim 9 which further includes an actinic light activatable free-radical polymerization initiator.

18. A composition according to claim 17 wherein said initiator is diethoxyacetophenone.

19. A composition according to claim 6 wherein Rf is selected from the group consisting of fluorinated alkyl, alkoxyalkyl, or perfluoroalkyl having a formula CnF2n+1, wherein n has a value of from 1 to 12.

20. The composition according to claim 6 which further comprises ethylenically unsaturated diluting monomers.

21. The cured composition according to clalms 1 or 6.