Note: Descriptions are shown in the official language in which they were submitted.
FN 913,505
ULTRAVI0LET RADIATION PROTECTIVE
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
--7
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
--8--
~ --\
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.
-14-
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~
-18-
.
. :
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
-19-
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
-20-
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
-21-
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~
-22-
: '
-, . .. . ,... - . ,,: ~ . ,
~ ~ rl
-IJ
~: r l 11
O P~
U C)
r i O ~1 0
U~ Z
~ a) ~r~ r
O r-l
r-l I~
r-l P ~
~1 ~ O --I
U~ U~ Z U~
a) ~ ~
11~ rl
1: 1;~, ~ r~ J ~
11 al
~ ~ ~ ~1
C~ ~ ~
H IIJ O r; r;
~1 Z t~
r
E~
~ ~ ~ .
.~ O
~1
~r~ ~
(D -1
~ o ~ ta
~r . .
S-~
If
~) O O 1-1 H
$ ~Z; )~I ~1 :
~rl
1~1
Id
C)
--23--
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
-24-
- .
. .
rl
S~
n~ aJ
5~
~ul~o~ oN - ~IUO ~UI~a ~1~) o
~rl ~ (D
rJ
N ,S ~ rl
N O
~;~9 ~ N
o o o Ei a) ~
O ~J ~rl ~:
~k' ~ r
N O ~)
> ~I E
o o o
/d a) Q ~:
[Q E-l ~ rl
~ rl a) r-l
N ~ ~) ~ ~ U~
I ~ rl
o o o
r~ O ~
~ ~ O O
(~
~ O ~ ~ `~
o o o
~ 1~
H N Q~ h O
a~ 1~u~ ~ N O ~ Ei a~ r
~-1 o o o ~,1 0 ~ a
Q ~ O o ~.
.,.
aJ
0 ` R t
In ~
~ a~h ~1~-rl
_ /
O Y~ ~ ~-rl rl
d--` O I 11) IH rl~q O O O ~H
~1a~ ~ ~ N ~ a! rl ~rl
.) ~ rrS ~I
~O ~ O_ ~ ~
Orl C.) O O ~ C) 1; 0 O ra 0 0 ~1
li~ U~ O t ~ ~ ~J rl 0 J ~ ~D
\ ~ Q Pl ~S-l U~ Orci
N $~ U O
1t~ J 5 ~ > SJ ~1 U) ~3
a)~ u H Q ~ 3
~1C) U ~ 0 ~ 1 0
'- U- O
a) O O O o u~ o U) ~1 0
~1 N N ~ 1 ~2 0 ~ 1~1 ~D rl
r lS~
.) V ~ 1 0
V ~ ~ ~ J ,c~
O i O
~ tq ~7 ~ C)~ ~ @
c> u o o
--25--
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:
-26-
.
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
-27-
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.
-28-
.'` `' ' : -: ..:
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
CH3
~O-Si ~ O-C-CH2~m
CH3 CH3
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
17 BPM 0015 ECD 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
-31-
.
~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~
