CA1109589A

CA1109589A - Ultraviolet radiation protective, abrasion resistant, bloom resistant coatings

Info

Publication number: CA1109589A
Application number: CA298,038A
Authority: CA
Inventors: Larry A. Lien; Ashwani K. Mehta; J. Lamar Zollinger; Kathryn A. Soine
Original assignee: Minnesota Mining and Manufacturing Co
Current assignee: 3M Co
Priority date: 1977-03-28
Filing date: 1978-03-02
Publication date: 1981-09-22
Also published as: DE2812848B2; DE2812848C3; JPS53121100A; ES468226A1; MX150989A; AU3445678A; FR2385771A1; SE438321B; BR7801847A; IT1156179B; EG13298A; SE7803389L; CH640251A5; AU508257B2; DE2812848A1; IT7848603A0; GB1596234A; FR2385771B1; AR222461A1

Abstract

Abstract of the Disclosure Abrasion resistant coatings based on epoxy-terminated silanes can reduce the transmission of ultraviolet radiation by at least 90% with the addition of ultraviolet radiation absorbers and 10-70% by weight of an aliphatic, polyepoxide, flexibilizing comonomer.

Description

FN 913,505 ABRASION RESISTANT, BLOOM RESISTANT COATINGS

There are man~ di~erent factors wh1ch can 11mit t~.e durability of articles besides normal wear during use~
Color fading, surface abrasion, and soiling, for example~
can su~iciently diminish the aesthetlcs o~ an ar~ic~e so that it ought to be replaced. Some items such as photo-graphs and works o~ art cannot be replaced when such damage has been wrought on themO Most organic ma-terials, including dyes and pigment, are susceptible to degradation by light, the ultraviolet region o~ the electromagnetic spectrum (approxlmately 290 to 400 nm) being the most damaging radiationO As conventional fluorescent lighting emits some ultraviolet radiation in this region, avoidance o~ sunlight is not necessarll~ comple~e protection ~rom such radiation~ In the past, clear ~ilms o~ s~nthetic polymers containlng ultravlolet absorbers have been used to protect certain items, includlng color photograph~, agalnst ~ading caused by ultravlolet radiationO The addition of such protective coatings, although reasonabl~
e~fective against ~ading, have not provlded protect~on against other deleterious effects such as abrasion and soiling. The coatings also must ~enerally be able to pro~
vlde impact resistance and flexibility~ especially on an article such as a paint,lng or color photo~raphc UOSO Patent No. 4,049,861 discloses abrasion resistant coatlngs based upon the polymeriæatlon of epoxy-terminated silanesO A high degree o~ abraslon resistance is provlded by that technology Australlan ~-~3 - ~ Patent NoO 483,792 and U.SO Patent e~L ~ Se ~r -::

No. 4,101,513 also disclose abrasion resis-tant coatings based on epoxy terminated silanes as does U.S. Patent No. 3,955,035. The above identified U.S. Patent No.
4,049,861 also diseloses the use of the coatings on photographic films, the ability to provide flexibility with the coating, and the general utility of ineluding ultraviolet absorbers in the coating, although the three respeetive disclosures are not specifieally eombined.
Although ultraviolet absorbers ean be added to the abrasion resistant coatings aecording to the teachings of the above identified applications, only limited eoneentrations of the ultraviolet absorbers ean be readily retained in the generally deseribed eoatings of those inventions. The concentrations which can be used provide only limited proteetion against ultraviolet radiation. Larger eon-eentrations eause "bloom" to form on the coatings, a white, dusty appearance in the film caused by the preei-pitation of the absorbers within the film coating or on the surface of the coating~ ~his bloom appeared in compositions independent of the catalysts used, whether ~- the highly fluorinated aliphatic sulfonylic or sulfonie eatalysts of ~.S. Patent No. 4,049,861, the onium eatalysts of U.S. Patent No. 4,101,513, the metal ester eatalysts of Australian Patent No. 483,792 or the Lewis aeid eatalysts of U.S. Patent No. 3,955,035. ;~
The present invention relates to an abrasion resistant, bloom resistant coating for use on substrates which are suseeptible to damage from ultraviolet radiation, abrasion, and/or soiling. Abrasion resistan-t coatings derived ~rom epoxy-terminated silanes are used in the .

'~ '' ' : . . ,: , 58~

practlce of the present invention in comb1natlon with ultraviolet radiation absorbers The present invention copolymer~zes epoxy-terminated silanes with aliphatic~ polyepoxy materials to ~orm abrasion resistant coatings which are able to retain su~ficiently high concentrations o~ ultraviolet absorbers within the cured copolymer to provide effect~ve ultraviolet absorbing, abrasion resistant, and soil resistant coatings~ with signl~icant bloom resistanceO
The epoxy terminated s1lane comprises 30-90% by weight o~ the reactive materials ~ormlng the final composltlon, the aliphatic polyepoxy materials comprise 10-70% by weight o~ the reactive materials, and 0-20% by weight o~
other copolymerizable materials may be included as reactive materialsO It is pre~erred to ha~e 50-80% epo2y-termlnated silane, 10-50% polyepoxy material, and 0-10% comonomers.
The ultraviolet radiation absorbtive matèrials~ not included within the description o~ reactive materlals ~although some may be reactive during copolymerization and still provide ultraviolet radlation absorpt~on) must be present in an amount su~ficient to be absorptlve o~ at least 90% of all radiation between 290 and 400 nm and be transmissive of at least 90% o~ all radiatlon between .
400 and 780 nm with no less than 75~ transm~ssi~lty of any 50 nm range between 400 and 780 nmD Preferably there is no less than ~0% transmissivity over any 100 nm range between 4Q0 and 780 nmO Any of the above descrlbed eatalyst systems for the curing of epoxy-termlnated s~lanes into abra~lon resistant coatings may be used in the present invention~ The prefe~red catalyst systems are the high:ly .

fluorinated aliphatic sulfonyl catalysts of U.S. Patent No.
4,049,861 and the onium catalysts of U.S. Patent No.
4,101,513.
The thickness of the coatings in the present invention may be between 0.5 and 500 microns, the more pre-ferred range being between 0.5 and 50 microns. The most preferred fllm thickness is between 1.0 and 20 microns.
Epoxy Termlnated Silanes Epoxy-terminated silanes are compounds or materials having polymerizable (preferably terminal) epoxy groups and terminal, polymerizable silane groups, the bridging of these groups being through a non-hydrolyzable aliphatic, aromatic, or mixed aliphatic-aromatic divalent hydrocarbon radical which may have N and/or O atoms in the radical chain. It is preferred to have no N atoms and most pre-ferred to have O atoms only adjacent the epoxy group. The O atoms, for example, would be within the chain only as ether linkages. These radical chains may be generally sub-stituted as is well known in the art, as substituents on the chain do not greatly affect the functional ability of the epoxy-terminated silanes to undergo the essential reactions necessary for polymerization through the siloxane or epoxy terminal groups. Examples of substituents which may be present on the linkage or bridging moieties are groups such as NO2, alkyl (e.g., CH3(CH2)nCH2), alkoxy (e.g., methoxy), halogen, etc. In genera] structural formulae appearing within this description of the invention, such allowable substitution o~ the bridging moieties is included unless specifically excluded by language such as "unsubstituted divalent hydrocarbon radical".
,-'.

Examples of preferred epoxy-terminated silanes useful in the practice of this invention are compounds o~
the general ~ormulae:

2 CH~R~n~ Si(OR~)m and ~ S1(OR') 4-m 4-m where R = a non-hydrolyzable divalent hydrocarbon radical (aliphatic, aromatic, or mixed aliphatic-aromatlc contaln~n~) of le s than 20 carbon atoms or a divalent radical of less than 20 carbon atoms composed of C, N, S, and O atoms (these atoms are the only atoms which should appear in the backbone of the divalent radicals), the oxygen bein~
in the form of ether linkages. It is pre~erred to have no N atomsO No two heteroatoms may be ad~acent within the backbone o~ the divalent hydrocarbon radical. This description defines divalent hydrocarbon radicals ~or epoxy terminated siloxanes ln the practic~ of this 1nventionO
A more preferred formula definition of epoxy terminated silanes is CH2 - CH-R2-Si-(ORl)3 and ~ -R2-Si(ORl)3 wherein R2 is a n~n hydrolyzable divalent hydrocarbon radical of fewer than 20 carbon atoms or a divalent group of fewer than 20 carbon atoms the backbone o~ which is composed o~ only C, N, S, and O atoms with no ~wo ad~acent heteroatomsg and R is an aliphatic hydrocarbon group or acyl group of fewer than 10 carbon atom~. :

The compositions employed in this invention can be an epoxy silane of the above formula in which n ~s from 0 to 1, R is any divalent hydrocarbon radical such as methylene, ethylene, decalene, phenylene, cyclohexylene~
cyclopentylene, methylcyclohexylene, 2-ethylbutylene, and allene or an ether radical such as -CH2-CH2~O-CH2-CH29 -(cH2-cH2o)~-cH2-cH2 ' ~ O_CH2-CH2- and -CH2O-(CH2)3 R' can be any aliphatic hydrocarbon radical of less than lO carbon atoms such as methyl~ ethyl, isopropyl, butyl, vinyl, alkyl, or any acyl radlcal o~ le~s than 10 carbon atoms such as formyl, acetylg propionyl, or any radical o~ the formula (CH2CH2O)kZ in which k ls an integer o~
at least 1, and Z is hydrogen~
The most preferred epoxy-terminated sllanes are those represented by the formulae:

H2\ / ~-(CH2)m~~(c~2)n-sl(OR)3 and o (CH2)m~~~cH2)n-sl (OR)3 wherein R is an alkyl group of up to 6 carbon atoms, and m and n are lndependently 1 to ~O
The compositions may additionally contain addenda such as surface actlve agents, viscosity modi~lers, : spreading a~ds, dyestu~fs, etcO These may be blended w~th other epoxy terminated ~ilanes and comonomers to ad~ust the physical properties of the final coat~ng~ Comonome:rs

3 ~ !' 5 ~ ~

are those materials known in the art to be copolymer~zable with epoxy groups or sllane groups and i.nclude epo~les an~ silanes~
Catalysts Catalysts ln the present invention are generally used in amounts o~ f~rom OoOl to 10~ by weight of` the reactive ingredients in the curable composltion~ Pref'erably f~rom 0O5 to 5% by weight is used, the amount vary~.ng with the particular catalyst used. The most pref`erred cata.lysts according to the present inventlon are highly fluorinated aliphatic sulfonylic catalysts and onlum catalystsO The related highly ~luorinated aliphatic sulfonic catalysts are very usef'ul as are certain Lewis and Bronstad acids, but are less preferred~ The sul~onic materlals are defined as a highly f`luorinated allphatic sulfonic acid or salt thereo~. Fluoroaliphatic sulfonic acids~ methanes and imides and their preparation are disclosed :~n U~SO Patent No. 4,049,861~ The sulfonylic materials are def`lned as a compound containing kwo highly fluorlnated aliphatic sulf'onyl groups attached directly to an imide or methylene ~eOg~, -NR'- or -CR~ RI~- ) o The sulf~onlc mater~als may be represented by the formula f 3)n wherein R is hydrogen, ammonium cation or metal cation and n i~ the valence o~ Ro The pre~erred sul~onyllc catalysts may be represented ~y the forrnula (R~02 ~ S2R f~
wherein Q is a dl.val.ent radical ~elected f~rom ~NR, -CRIR'' and C=CHR3 S8g wherein R" is selected from hydrogen~ chlorine, bromlne, iodine, R~S02-~ alkenyl o~ 3-4 carbon atoms, alkyl o~ 1 to 20 carbon atoms ~pre~erabl~
1 to 1l~ aryl o~ 1 to 20 carbon atoms ~pre~erably to 10, and for example, phenyl, naphthyl, pyridyl, benzthienyl, etcO), and alkaryl o~
7 to 20 carbon atoms (pre~erably to 10), R~
is selected ~rom hydrogen 3 chlorine, bromine, ~odine, ammonium cations or metal cations, and R3 is H, alkenyl (3 to 11) carbon atoms or aryl up to 20 carbon atomsO
The catalysts wherein the N or C atom bonded to the hlghly ~luorinated aliphatic (preferably alkyl) group has a hydrogen atom bonded thereto are active catalystsO Those ~ 15 having no hydrogen atom are latent and may be activated `~ by heat, acid, chelating agent or comblnations thereo~ as known in the artO
ln the practlce o~ th~s invention, R~ and R'~
are independently highly fluorinated aliphatic radicals ; 20 which are defined as fluorinated, saturated, monovalent, aliphatic radicals having 1 to 20 carbon atomsO The skeletal chain o~ the radical may be straight~ branched, or, i~ su~icierltly large (e~gO, at least 3 or 5 atoms) cycloaliphatic, and may be interrupted by divalent oxygen atoms or trivalent nitrogen atoms bonded only ~o carbon ~: atomsO Preferably ~he chain of the ~luorinated aliphatic radical does not contain more than one hetero atom, iOe~
nitrogen or oxygen9 ~or ever~ two carbon atoms ~n t~e : skeletal chainO A fully ~luorinated group is preferred, but hydrogen or chlorine atoms may be present as ~ --\

substituents 1n the fluorinated aliphatic radical provided that not more than one atom of either 13 present in the radical for each carbon atom. Preferably, the ~luoro-aliphatic radical is a saturated perfluoroalkyl radical having a skeletal chain that is straight or branched and has a formula CxF2x~1 wherein x has a val.ue from 1 to 180 'rhe most preferred sulfonylic actlve catalysts of this invention are those compounds having the ~ormula ~R~S02)-Q-(02SR'f) wherein ~f and R'f are independently a highly fluorinated alkyl group~ and Q is a dlvalent radical selected from -NH- and CHR-, wherein R is selected from Br, Cl, I, H, alkyl groups of 1 to 20 carbon atoms (preferably 1 to 4)~
alkenyl of 3 to 4 carbon atoms, aryl or aralkyl of up to 20 carbon atoms (pre~erably up to lO)g or R'X, wherein R' is an allcylene group of up to 20 carbon atoms (preferably 1 to 4) and X
is H, Brg Cl, I, -02SR~, -CH(02SR~2, CH-(CH2)n-CooR4, or -CY(COOR2)2 Br wherein R4 ls H or 1 to 8 alkyl and n is 0 to 8, and wherein R2 ls alkyl of 1 to 4 carbon atoms or phenyl-alkyl, the alkyl group of which has 1 to 4 carbon atoms, and Y is H, Br~ C1, Ig or NO2O
Ammonium cation as used in the present invention is defined as cations of a~nonia, primary,lsecondary~
tertiary and quaternar-y amlnesO Alkylg aryl, alkarylg g_ - , ., .. , , ., . . . ., . ~ ... . . .

etc , as used in the present invention (excluding R~ type groups as elsewhere de~ined) includes such slmple subst~-tuted groups as are recognized in the art as f`unctional equivalents of the groups (e~g.~ -CH2CH2CH2Cl;
-SO3- ~ ~O Selection of a most preferred perfluoro-alkyl sulf`onyl methane catalyst is dependent on the partlcular monomer compositions ln which the catalyst ~s to be used and the application for which the composltlon ls to be usedO
Although their use is not necessary in the compositions of the invention to e~ect a cure of coatings of the compositlon~ it is o~ten preferable to lnclude ln addition to the fluoroalkylsulfonyl protonic acid ca-talysts ; from about 0,01 to 5 percent and preferably about 0.1 to 2 percent o~ a second siloxane hydrolysis and condensation catalyst. As is illustrated in the examples, some of' such combination of catalysts provldes synergistlc e~ects allowing for increased rate of cure over that obtalnable by the fluoroalkylsulf`onyl protonic acid catalyst alone~
Such siloxane hydrolysis and condensation catalysts are well kno~n and are descrlbed ln part in UOSO Patent No~

4,049,861O
The metal ester catalysts useful in the present lnvention are metal esters o~ aluminum, titanium, or zlrconium having at least two ester group~ of the f'ormula -OR directly bonded to the metal wherein R is hydrocarbyl of 1 to 18 carbon atoms, and more pref`erably alkyl or acyl o~ 1 ~o 8 carbon atomsO The remaining valences of the metal may be satisf'ied by organic moleties~ inorganlc moietles, cvmplexing agents or even repeating -O-Ti-O--10- ;, : ... . . .

groups etc~ ~pre~erably, if remalning valences are not satis~led by OR groups, halides or alkyl groups are used)O
As long as two o~ the ester groups are present, the meta ester can react lnto the final polymeric structure and catalyze the reactlon to form an abrasion resistant coating~
It is generally preferred that all valences o~
the metal are satisfied by ester groups, but the other groups may be present so long as at least two ester groups are presentO Compounds of the ~ormula R'nM(OR)m n are therefore use~ul, wherein R is as de~ined above, m is the valence of M and n is 0, 1 or 2 such that m-n is always at least 2, and R' is an organic or inorganic moiety bonded to M or a complexing agent satisfying the valence requirements o~ Mo Compounds o~ the formula M(R)m are generally preferred because o~ ava.11ability and generally imp:roved characteristics. M ls a metal, pre~era~ly titanium, aluminum~ or zirconium~
It i.s critical that the metal ester not be hydrolyzed completely or hydrolyzed to a condition where less than two ester groups per t~taniurn atom are present on the metal esterO l~ the rnetal ester ls so hydrolyzedg the amblfunctional silane and the metal ester will coprecipitate into an insoluble materlal because reactive sites for the silane on the ester have been remGvedO
The onium catalysts which are pre~erred in the practice of the present ~nvention are aromatic, organlc ~11-adducts of an aromatic organoatomic catlon of a Group Va, VIa, or VIIa atom particularly phosphorous, antimony, su1fur3 nitrogen3 and iodine atoms, and an anionO~
Aromatic as used in the description o~ the g.roups on the onium cat~lysts as used in the present invention means an aromatic or heterocyclic ring (phenyL~ naphth~l, substituted or unsubstituted 5, 6 3 or 7 membered heterocycl~ comprised of only C, N, S~ 0 3 and Se atoms with no more than one atom in the ring selected from S, O, or Se atoms) so attached to the nominative atom that it is at least as electron withdrawing as benzene~

For example, phenacyl ~ -C-CH2~ would be a use~ul aromatic group (being at least as electron withdrawing as benzene), but benzyl ~ CH2- would not be as use~ul because of instability o~ the compound which would impair storage stabilityO Representatlve aromatic rings are phenyl, naphthyl, thlenyl, pyranyl, ~uranyl and pyrazolyl, substituted or notO
A descrlptive ~ormula for the onium catalysts o~ the present inventlon would be n A x ~ Rl) whereln R is an aromatic group at least ~æ electron withdrawing as benzene, *For purposes of convenience in describ1ng these onium catalysts the Group Va, VIa, or VIIa atom that provides the ma~or nomenclature ~or the adduct (eOgO~ phosphorous in phosphonium, sulfur in sulf~onium, iodine in iodonium~ etc~) wil.l be called the nominative atomO

-12~

. ~ . -: . . .

~\

Rl is R or alkyl (straight, branched, cycllc or substituted) or alkenyl havin~ 1 to 18 carbon atoms~
n is a positive whole integer of at least 1 (preferably 2) up to the valence o~ A plus one~
a is O or a positive whole integer Or up to the valence of A (preferably A minus 1), n plus a is equal to the valence of A plus one, A is a group Va~ VIa, or VIIa atom, and X is an an~on, with the proviso that when A is halogen, n is at least 20 These onium materials are already known in the art. For example, Belgian Patents 833,472; 828,668;
828,669; and 828~670 show the use of certain onium com-pounds as cationic polymerization catalysts for specific monomers O
: Other organo groups attached to the Group Va, or VIa nominatlve atom can be the same aromatic group or a substituted or unsubstituted alkyl or cycloalkyl group~
The organo groups o~ up to 4 carbon atoms, R' is an alkyl group of up to 6 carbon atoms, and u is O or 1~
The presence of catalytic amounts of molsture ha~ been found to be necessary in the initiatlon of the condensation of silanes with those catalysts~ Atmospher~c -~
moisture will usually be su~ficient, but water may be added ~ -to the system if deslred or if polymerization is needed in the absence of ai-r for any particular applicatlonO
. Examples of suitable onlum salts lnclude, but are no~ limited to:

~13-s~
A. Onium Salts Having a Periodic Group Va Cation 4-acetophenyltriphenylammonium chloride Diphenylmethylammonium tetrafluoroborate Tetra(4-chlorophenyl)phosphonium iodide S Tetraphenylphosphonium iodide Tetraphenylphosphonium hexafluorophosphate (4-bromophenyl)triphenylphosphonium hexafluorophosphate Tetraphenylarsonium tetrafluoroborate Tetraphenylbismonium chloride Di-(l-naphthyl)dimethylammonium tetrafluoroborate Tri-(3-thienyl)methylammonium tetrafluoroborate Diphenacyldimethylammonium hexafluorophosphate Examples of these and other onium salts and their preparation are disclosed in Belgian Patent 828,668.
B. Onium Salts ~aving a Period Group VIa Cation Triphenylsulfonium hexafluoroantimonate 4-chlorophenyldiphenylsulfonium tetrafluoroborate Triphenylsulfonium iodide 4-cyanophenyldiphenylsulfonium iodide Triphenylsulfonium sulfate 2-Nitrophenylphenylmethylsulfonium sulfate Triphenylsulfonium acetate Triphenylsulfonium trichloroacetate Triphenyl teluronium pentachlorobismutate Triphenyl selenonium hexafluoroantimonate Examples of these and other onium salts havin~ a Periodic Group-VIa cation and their preparation are given in Belgian Patents 828,670 and 833,472.

C. Onium Salks Having a Periodic Group VIIa Cation Diphenyliodonium iodide 4-Chlorophenylphenyliodonium iodide Diphenyliodonium chloride 4 Trifluoromethylphenylphenyliodonium tetra~luoroborate Diphenyliodonium sulfate Di(4-methoxyphenyl)iodonium chloride Diphenyliodonium trichloroacetate 4-methylphenylphenyliodonium tetrafluoroborate Diphenylbromonium chloride 1-(2-carboethoxynaphthyl)phenyliodonium chloride 2~2'-Diphenyliodonium hexafluorophosphate Examples of these and other halonium salts and their preparation are disclosed in Belgian Patent 828,66g and Belgian Patent 845,746.
The compositions o~ the invention can be prepared by mixing the onium salt with the epoxy terminated silane composition until a solution is formed~ Because many of the onium salts have limited solubillty in the silicon-containing compound, it is often preferable to first dissolve the onium salt in a llquid diluent that is inert ko the components o~ the composition and then mix thls solution into the reactive compositionO Suitable inert diluents,include alcohols such as ethanol~ esters such as ethyl acetate 7 ethers such as diethyl ether, halohydrocarbons such as dichloroekhane, and nitriles such as acetonitrileO For storage skability~ these solvents and the solutions must be anhydrous.

The aromatic iodonium salts are of the formulae:
~Ar~ 2 / ~

wherein Arl and Ar2 are aromatic groups ha~ing 4 to 20 carbon atoms and are selected ~rom phenyl, naph~hyl, thienyl, furanyl and pyrazol~l groups;
11 ' W is selected from 0, S, S=0, C=0~ 0=S~0~ R -N
where Rll is aryl of ~ to 20 carbon atoms or acyl o~ 2 to 20 carbon atoms (such as phenyl, acyl, benzoyl, etc.); a carbon-to-carbon bond;
or R12-C-R13, where R12 and R13 are selected from hydrogen, alkyl groups o~ 1 to 4 carbon atoms, and alkenyl groups of 2 to 4 carbon atoms;
and b is zero or l; and Q is a halogen-containing complex anion selected from tetrafluorobor~te, hexafluorophosphate, hexafluoroarsenate, hexachloroantimonate and hexarluoroantimonate;
a fluoroaliphatic sulfonic acid; a bis-(fluoroaliphaticsulfonyl)methane; or a bis(fluoroaliphaticsul~onyl)imideO
Pre~erred compounds from this group lnclude those where n=0. Further pre~erred materials have Arl and Ar2 as a phenyl group.
The aromatic sulfonIum salts are of the ~ormulaeo Arl Arl Ar2 _ ~ ~ and Ar2 Rl ~1 ~16-.

wherein Arl and Ar2 can be the same or di~erent~
selected from aromatic (as defined above ~or aromatic iodonium salts) and Rl, W, and Q are the same as de~ined be~ore. Preferred compounds of this class are those in which Ar2 and Rl are phenyl.
Suitable examples of the preferred aromatic onium salt photocatalysts include~
diphenyllodonium tetra~luoroborate diphenyliodonium hexa~luorophsophate ; diphenyliodonlum hexafluoroarsenate dlphenyliodonium hexachloroantimonate diphenyliodonium hexafluoroantimonate diphenyliodonium bis(tri~luoromethylsul~onyl)-methane Other suitable preferred aromatic onium salt photocatalysts are the corresponding triphenylsul~onium salts. Still other preferred salts are llsted ln Belgian Patent NoO 845,746 and include triarylsul~onium hexafluorophosphate, tritolylsul~onium hexa~luorophosphate, methyldiphenylsulfonium tetrafluoroborate, etc D
The aromatic onium salt phokocatalysts use~ul in the photopolymerizable compositions of the lnvent,ion are o~ themsel~es photosensitlve only in the ultraviolet.
They are latent catalysts which must be mixed with the reactants then activated by irradiationO They can be ~urther sensitized to the near ultraviolet and the visible range o~ the spectrum by sensitizers for known photoly~able iodonium compounds in accordance wlth the teachings of UOSO Patent 3,729,313-Polyepoxy Compound Polyepoxy compounds according to the present inventlon have the formula:

\
. , n a b wherein R is an aliphatic or cycloaliphatic radical such that the epoxy compound has a molecular weight of at least lO0 per epoxy group to prevent bloom.
It is more preferred to be a compound having a molecular weight of at least 150 per epoxy group to a~d significant flexibllity improvement.
Allphatic and cycloaliphatic refer to hydrocarbons which also may have ether and ester oxygens and thio ether groups therein~ n is the valence of R and is an integer o~ 2 to 6 (preferably 2). a and b are H or, when fused together, the atoms necessary to form a 5-or 6-member cycloaliphatic ring~ R is preferably selected so that the flexibilizing epoxy compound, upon homopolymerization provides a polymer having a glass transition temperature (Tg) below -25Co Use~ul ~olyepoxide~ wh~ch are also ~lexibilizi.ng epoxies within this definition ~urther include those whi~h contain one or more cyc'ohexene oxide groups such as the epoxycyclohexanecarboxylates, typifled by 3,4-epoxycyclo-hexylmethyl 2 ~ 4-epoxycyclohexanecarboxylake, 3,4-epoxy-2-methylcyclohexylmethyl 3,4-epoxy~2-methylcyclohexane~

.
. :

carboxylate, and bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate. For a more detailed list of flexibilizing epoxy compounds according to the present invention, see U.S.
Patent No. 3,117,099, particularly column 2, line 59 -column 4, line 22, which is incorporated herein for that disclosure.
Other useful flexibilizing epoxy compounds include polyglycidal ethers of aliphatic polyols such as 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, diethyleneglycol diglycidyl ether, triethyleneglycol diglycidyl ether, polypropyleneglycol diglycidyl ether (e.g., "ERL-4050"* and "ERL-4052"*
from Union Carbide Corp.), diglycidyl ether of 2,5-dioxanediol, and the triglycidyl ether of trimethyl-olpropane; epoxidized polyolefins such as dipentene dioxide (e.g., "ERL-4269"* from Union Carbide Corp.) and epoxidized polybutadiene (e.g., Oxiron* 2001 from FMC
Corp.). Other useful aliphatic polyepoxy compounds are disclosed in Handbook of Epoxy Resins, McGraw-Hill Brook Co. (1967).
Ultraviolet Absorbers Ultraviolet absorbers within the preferred prac-tice of this invention fall into the following classes:
BENZOPHENONES: This class comprises substituted 2-hydroxy-substituents on the basic molecule to provide proper compatibility, non-volatility, and particular absorption properties. Typical substituted 2-hydroxybenzophenones are 2-hydroxy-4-methoxy-benzophenone, 2-hydroxy-4-octyl-oxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, and * Trademarks and 2,2'-dihydroxy~4,4'-dimethoxybenzophenoneO The art recognizes substituted 2-hydroxybenzophenones as a class.
BENZOTRIAZOLES: This class comprises derlvatives of 2-(2'-hydroxyphenyl)benzotriazole Typical examples are 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole. Substituted 2 (2'-hydroxyphenyl)benzotriazoles are also an art recognized class of ultraviolet radiation absorbersO
SUBSTITUTED ACRYLATES: These are another art recognized class of UV absorbers. Typlcal examples are eth~l-2-cyano-3,3-diphenyl acrylate~ 2-ethylhexyl-2-cyano-3,3-diphenyl acrylate, and p-methoxy-benzylldene malonic acid dimethyl ester ARYL ESTERS: This art recognized class includes aryl salicylates, benzoates, and esters of resorcinol~ Typlcal examples are phenyl salicylate, p-t-octylphenyl salicylate, resorcinol monobenzoate, and 2,4-di~t-butyl-phenyl~3,5-di-t-butyl-4-hydroxybenzoate. CombinatlGn~
of these UV absorbers are often used to aggregate the properties Or the individual absorbers. Preferred absorbers are (I) 2,4-dihydroxybenzophenone, ~II) 2,2'4,4'-tetrahydroxyb~nzophenone, (III) 2-~2'-hydroxy-5-methylphenyl)benzotriazole and (IV~ 2-(3'g5'~
di-t-amyl-2'hydroxyphenyl)benzothiazole~
Reference to the ~ollowing examples will provide further understanding of the present inventionc Example 1 A coating ~ormulation (A) was prepared in the following manner. 6.o grams o~ y-glycidoxypropyltrimethoxy-silane were partially hydrolyzed (40% methoxy groups removed) and str,ipped of volatiles. 4.0 g diglycidyl ether of 1,4-butane diol was added to the partial hydrolyzate alone, with 0~1 g of bis(tri~luoromethyl-sulfonyl)phenylmethane in ethyl acetate, 0.01 g o~ an, inert, ~luorinated oligomeric leveling agent, 8~89 g of ethyl acetate and 1.0 grams o~ 2,4-dihydroxybenzophenone.
A second coating formulation (B) was prepared as above for A~ except no UV absorber was addedO Two color photographs were coated wlth formulatlons A and Bg respectlvely, using a #22 wire wound steel coating rod~
The coatings were allowed to cure at room temperature for 4 hours, then placed under a 200 watt medium pressure ,mercury ultraviolet lamp, along with an uncoated color photograph. After 7 hours, the uncoated photo and the photo with coating B had begun to fade, buk no ~ading was observed on the color photograph coated with ~ormulation A. After 17 hours of irradlation, severe fading and color destruction had taken place on the uncoated photograph and the photograph coated with formulation B, but no fading or color change was observed on thé photo coated with the A formulation contalning the UV screen I, The photographs coated with A and B were highly resistant to abrasion by steel wool ~#000), and wiping with a wet paper towel.
Example 2 .
Coating formulations were pre,pared as in Example 1 except that the following UV absorbers and amounts were employed:
Formulation W Absorber B None C 002 g (2%) of I
D 0.2 g (2%) o~ II
E 0.2 g (2~) of IV
Following the procedure o~ Example 1~ coatings were applied to color prints which had a whlte background and areas o~ pure cyan 9 magenta and yellowO These coated photographs were placed under a 275 watt GE sunlamp (ten inch distance)O After 2 days o~ irradiation it was noted that the cyan region of the B coated print had ~aded, and the background white was tu.rning yellowO The C, D, and E coated prints showed little i r any change. The visual ra~ings a~ter 4 days irradiation are given belo~
in Table I~

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$ ~Z; )~I ~1 :

~rl 1~1 Id C) S~

Example 3 In the ~ollowlng example, 100% solids, UV cured protec~ive coatings are described.
The formulations (F through K) described in Table II were coated with a #3 wire wound rod on the color prints described in Example 20 The coatings were cured - immediately under a 200 watt medium pressure mercury UV
lamp for 40 seconds, followed by heating at 60C ~or 10 minutes. An uncoated color photographic print was used for comparison - .
. .

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.) V ~ 1 0 V ~ ~ ~ J ,c~
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c> u o o Example 4 Rigid poly(vinylchloride) sheet can also be protected according to the present invention. In this example a primer was found to be desirable to enhance the bond between the UV absorber containing abrasion resistant coating and the sheet. A terpolymer o~ ethyl-methacrylate, butyl acrylate, and methacryloxypropyl-triethoxysilane (80:17:3, respectively) was applied from a 10% solids solution in toluene/ethylacetate (50/50) using a number 14 wire wound applicator rod, then dried ~or one hour at room temperature before application of the overcoat.
A~ter prlming, the abrasion resistant coatings (with or without necessary modi~iers as later described) were applied ~rom a 50% sollds solution in ethyl acetate using a number 14 wire wound applicator rodO The coatings were allowed to cure to 5 days at room tempera-ture. All abrasion resistant coating constructions exhibited good crosshatched adhesion (at least 85%) and excellent abrasion resistance to steel wool in comparison with poly(vinylchloride).
Three constructions were compared: A) a control (having no abrasion resistant coating); B) an abrasion resistant coating wlth W abosrbers but no flexibiliælng epoxy material; and C) an abrasion resistant coating with W absorbers and ~lexibilizing epoxy materialsO The compositions of the coatings used in B and C were:

.

B C
_ Component (parts) r-glycidoxypropyltrimethoxylOoO 600 silane Diglycidylether of 1,4-butane - L, o o ~iol 2,4-Dihydroxybenzophenone 200 200 Ethyl acetate 120 0 1200 Trifluoromethylsulfonyl- Ool Ool phenylmethane Inert fluorinated oligomeric OoOl OoOl surfactant The Examples were treated in cycles by placing them 10 inches (2504 cm) from a 275 watt sunlamp for 4 hours then immersing them in water for 4 hoursO The results were as fo].lows:
20 hours A Light brown discoloration B Hairline cracks on surface C No change 95 hours A Brown discoloration throughout B Sur~ace thoroughly cracked but no discoloration C No change 650 hours A Sample dark brown and opaque B Severe cracking C Small hairline cracks begin to appear 800 hours A Total failure o~ sample B Large cracks and slight discoloration appearing ln coating C Some more crackingJ but no discoloration Examples 5-15 The following materials were used in these examples.
A~ y~glycldoxypropyltrimethoxysilane B. A 40% hydrolyzed precondensate of y-glycidoxypropyl-trimethoxysilane C. 1,4-butanediol diglycidylether D. 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate E. bis(2-methyl-3,4-epoxycyclohexylmethyl)succinate F. 2-(2'-hydroxy~5'-methylphenyl)benzotriazole (5% in isopropylacetate) G. 2-(3',5'-di-t-amyl-2'hydroxyphenyl)benzotriazole (1~% in isopropylacetate) H. Isopropylacetate I. Inert fluorinated oligomeric surfactant J. bis(trifluoromethylsulfonyl)phenylmethane K. Inert organosilicon surfactant A11 coatings were applied with a number 22 wire wound rod, except ~or examples 10~ 12, 14 and 51 whlch were applied with a number 14 wire wound rod, and air dried overnightO Primed polyethyleneterep~thalate was used as a substrate.
Samples were exposed for 3 days at 2504 cm ~rom a 275 watt sunlamp3 The results were as follows in Table III.

.'` `' ' : -: ..:

Table III

Ex.
No. A B C D E F G H I J K
- 3 2 - ~ - 1.5 2.9 0.1 0.5

6 - 3 - 2 ~ 1.5 2.9 Ool 0.5

7 - 3 - 2 ~ ~ 1=5 2.9 - 0.5 0.1

8 3 _ _ 2 ~ ~ 1.5 2.9 - 0.5 0.1

9 - 3 - 2 ~ ~ 205 1.9 0.1 0.5 - 3 1 1 - 3.0 - 1.4 0.1 0.5 11 - 3 1 1 ~ ~ 1.5 2.9 0.1 0.5 12 - 3 1 _ 1 3.0 - 1.4 0.1 0.5 13 - 3 1 - 1 ~ 1~5 209 0.1 0.5 14 - 3 2 - - 3.0 - 1.4 0.1 0.5 - 3 - 2 - 3.0 - 1.4 0.1 0.5 Examples 6, 7, 9, 10, 12, 14, and 15 showed no bloom or discoloration~
Examples 8 and 13 showed slight bloom on close examination, but no discoloration~
Examples 5 and 11 showed de~inike, but reduced bloom but no discoloration.
The bloom in Examples 5, 8, 11, and 13 occurred because less efficient flexibilizing epoxies were used with ultraviolet radiation absorbers which exhibit the greatest bloom properties. Bloom was still reducedO All coatings exhibited excellent abraslon resistance.
Examples 16-21 These examples show the usefulness o~ other catalyst systems. A standard formulatlon o~ 60 parts y-glycidoxypropyltrimethoxysilane, 30 parts 1,4-butanedioi diglycidylether, and 10 parts bis(3,4-epoxycyclohexylmethyl) ~29-succinate was prepared. To aliquots o~ this formulation were added var~ous amounts o~ catalysts known to be use~ul in the cure o~ epoxy-terminated silanesO Among these were bis(trifluoromethylsul~onyl)phenyl methane (BPM) ~1.5% ln ethyl acetate~, tin tetrachloride (20% in 1,2-dichloro-ethane), antimony penta~luoride (5% in ClCF2CFC12), antimony pentachloride (10% in 1,2-dichloroethane), and perchloric acid (10% in acetic acid). Various amounts of UV absorbers and 0.1~ by weight of an organosilicone liquid o~ the formula ~O-Si ~ O-C-CH2~m wherein m and n are whole integers o~ at least 2 such that the liquid has a mean average molecular weight (Mn) o~ about 1500, a density of 0.99, and a viscosity of 125 centlstokes at 25C, were added before curing the compositions~ After coating over color photographic ~ilm and curing to an abrasion resistant ~ilm, the samples were evaluated for bloom resis~ancel abrasion resistance and W screening. All samples proved to be o~ high quallty~ The specific com-positions were as ~ollows, in addition to 10 parts of the standard curable composition. In Table IV the 2,4-dihydroxy benzophenone is represented as DHB, and 2-ethylhexyl-2-cyano-3,3-diphenylacrylate as ECD.

- . .
.

Table IV

Example Catalyst Wt. %UV Absorber Wt~
16 BPM 0.15 DHB 5 18~ SnC14 200 DHB 5 19* SbF5 0.25 DHB 5 20* SbC15 -5 DHB 5 21* HC104 200 DHB 5 *8-10% by weight of ethylacetate was necessary to keep these catalysts in the reactive solution.
Practice of the present invention was found to reduce blooming of the UV abosrbers independent of the catalyst systems used.
As noted above, any substrate which is in need o~ protection from ultraviolet radiation might be protected by the coating compositlon of the present inven~
tionO The coating composition~ having both reactive silane and epoxy groups will naturally adhere to many surfaces. Primers may be used to enhance adherence where necessary.
In the protection of conventional, wet-processed color photographic ~ilm or paperl it is necessary to place the protective coating over the viewing surface o~ the emulsion after development. The coating composition ~s generally impervious to aqueous materials and sol~ents, and if placed over the emulsion prl4r to development, developer solutions could not penetrate the coating to act upon the exposed emulsionO Certain color photographic elements contain déveloper solutions within the photographic element and need not be penetrated by developer solutions .

~rom outside the elementO In such photographlc element constructions, the abrasion resistant 3 ultraviolet absorbing coating may be applied to the element prior to development and prior to exposure. In ~act, where active solutions are released in photographic film by the physical rupturing of capsules or layers, the provision of the coating o~ the present invention protects against scratching of the surface of the photographic element which occurs during the rupturing procedure as well as providing protection against fading of the dyes therein from ultra-violet radiation.
Although emphasis has been placed in the description o~ the present in~ention on protection of dyes from ultraviolet radiationj it should be apparent that any substrate which can be deleteriously af~ected by UV radiation may be protected with the compositions described hereinO Polyolefins are notoriously sub~ect to damage by ultraviolet radiation~ vinyl resins are subject to severe discoloratlon problems from the cation of UV radiation, and both could be protected with coat~ng compositions of the present inventionO Any solid, rigid, or flexible substrate can be protected by these compositions although primers may be desirable in special instances.
Flexibility is another desirable aspect o~ khe present invention in many uses, In protecting conventional color photographic materials, instant printlng filmsg or motion pictures fllms~ flexibility is required. The UV
absorbing abrasion reslstant compositlons o~ the preserlt 3Q invention~ when coated onto a substrate or on a free film, can exhiblt excellent flexibility. The coatings and films can easily be wound about a 15 cm diameter cylinder at room temperature, and often have suf~icient flex~bili-ty to be wound about a 5 cm diameter cylinder. The substrates may be of any material~ Particularly suitable are substrates of flexible or rigid synthetic polymer resins such as poly(vinylchloride), polycarbonate 9 polyethyleneterephthalate, acryllc resins, poly(vinylchloride-vinyl acetate) copolymers, isocyanate based resins, and polymethylmethacrylate~
Painted surfaces are also usefully protected~

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An ultraviolet radiation absorbing, bloom resistant, abrasion resistant film of between 0.5 and 500 microns comprising the reaction product of:
1) 30-90% by weight of reactive ingredients of an epoxy-terminated silane, 2) 10-70% by weight of reactive ingredients of an aliphatic polyepoxide, 3) 0-20% by weight of reactive ingredients of a comonomer polymerizable with epoxy or silane groups, and 4) an ultraviolet absorbtive material present in sufficient amount so that the film absorbs at least 90% of all radiation between 290 and 400 nm, and is transmissive of at least 90%
of all radiation between 400 and 780 nm, with no less than 75% transmissivity over any 50 nm range between 400 and 780 nm.

2. The film of claim 1 wherein the epoxy-terminated silane comprised 50-90% by weight of reactive ingredients, the flexibilizing epoxide material comprised 10-50% by weight of reactive ingredients, and the comonomer comprised 0-10% by weight of reactive ingredients.

3. The film of claim 1 wherein said epoxy-terminated silane is represented by the formulae:

and where R2 is a non-hydrolyzable divalent hydrocarbon group of less than 20 carbon atoms or a divalent group of less than 20 carbon atoms the backbone of which is composed of only C, N, S, and O atoms with no two heteroatoms adjacent within the backbone of the divalent groups, and R1 is an aliphatic hydrocarbon group of less than 10 carbon atoms or an acyl group of less than 10 carbon atoms.

4. The film of claim 1 wherein said epoxy-terminated silane is represented by the formula:

wherein m and n are independently 1 to 4 and R is an alkyl group of up to 6 carbon atoms.

5. The film of claim 1 bonded to a substrate,

6. The film of claim 2 bonded to a substrate.

7. The film of claim 3 bonded to a substrate,

8. The film of claim 4 bonded to a substrate.

9. The film bonded to a substrate of claim 8 wherein said substrate is motion picture film.

10. The film bonded to a substrate of claim 5 wherein said substrate is photographic film.

11. The film bonded to a substrate of claim 5 wherein said substrate is instant color film.

12. A polymerizable composition comprising 1) 30-90% by weight of an epoxy-terminated silane, 2) 10-70% by weight of a polyepoxy resin of the formula wherein R is an aliphatic or cycloaliphatic group, n is the valence of R and is an integer of 2 to 6, a and b are H or, when fused together, represent the atoms necessary to form a 5- or 6-membered cycloaliphatic ring, wherein said epoxy resin, upon homopolymerization provides a polymer having a glass transition temperature below -25°C, and wherein said epoxy resin has a molecular weight of at least 100 per epoxy group, and sufficient ultraviolet radiation absorber to absorb at least 90% of all radiation between 290 and 400 nm through a wet film thickness of 20µ.

13. The polymerizable composition of claim 12 wherein said epoxy-terminated silane is represented by the formulae:

and where R2 is a non-hydrolyzable divalent hydrocarbon group of less than 20 carbon atoms or a divalent group of less than 20 carbon atoms the backbone of which is composed of only C, N, S, and 0 atoms with no two heteroatoms adjacent within the backbone of the divalent groups, and is an aliphatic hydrocarbon group of less than 10 carbon atoms or an acyl group of less than 10 carbon atoms.

14. The polymerizable composition of claim 13 wherein said epoxy-terminated silane is represented by the formula:

wherein m and n are independently 1 to 4 and R is an alkyl group of up to 6 carbon atoms.

15. The composition of claim 12 further comprising an onium catalyst comprising an aromatic adduct of (1) a diaromatic, triaromatic, or tetraaromatic organoatomic cation of a Group Va, VIa, or VIIa atom and (2) an anion, said onium catalyst being represented by the formula:

wherein R2 is an aromatic group at least as electron withdrawing as benzene, R1 is an alkyl or alkenyl group, A is a Group Va, VIa, or VIIa atom, X is an anion, n is a positive whole integer up to the valence of A plus one, a is 0 or a positive whole integer up to the valence of A minus one, and n plus a is equal to the valence of A plus one, and wherein at least two of said R2 groups are bonded to A.

16. The composition of claim 13 further comprising an onium catalyst comprising an aromatic adduct of (1) a diaromatic, triaromatic, or tetraaromatic organoatomic cation of a Group Va, VIa, or VIIa atom and (2) an anion, said onium catalyst being represented by the formula:

wherein R is an aromatic group at least as electron withdrawing as benzene, R1 is an alkyl or alkenyl group, A is a Group Va, VIa, or VIIa atom, X is an anion, n is a positive whole integer up to the valence of A plus one, a is 0 or a positive whole integer up to the valence of A minus one, and n plus a is equal to the valence of A plus one, and wherein at least two of said R2 groups are bonded to A.

17. The composition of claim 14 further comprising an onium catalyst comprising an aromatic adduct of (1) a diaromatic, triaromatic, or tetraaromatic organoatomic cation of a Group Va, VIa, or VIIa atom and (2) an anion, said onium catalyst being represented by the formula:

wherein R is an aromatic group at least as electron withdrawing as benzene, R1 is an alkyl or alkenyl group, A is a Group Va, VIa, or VIIa atom, X is an anion, n is a positive whole integer up to the valence of A plus one, a is 0 or a positive whole integer up to the valence of A minus one, and n plus a is equal to the valence of A plus one, and wherein at least two of said R2 groups are bonded to A.