U.S. patent application number 12/754375 was filed with the patent office on 2010-07-29 for optical coating composition.
This patent application is currently assigned to THE WALMAN OPTICAL COMPANY. Invention is credited to Gerald D. TREADWAY.
Application Number | 20100190010 12/754375 |
Document ID | / |
Family ID | 37679937 |
Filed Date | 2010-07-29 |
United States Patent
Application |
20100190010 |
Kind Code |
A1 |
TREADWAY; Gerald D. |
July 29, 2010 |
OPTICAL COATING COMPOSITION
Abstract
Coating compositions yielding cured coatings that exhibit
excellent abrasion--resistance and hardness for use on polymeric
substrates such as the front side of optical lenses, in a manner
that meets or exceeds the stringent requirements for such use. The
compositions include a monomeric organofunctional silane, and
colloidal silica present in an amount sufficient to improve
abrasion resistance as compared to a composition lacking the
colloidal silica.
Inventors: |
TREADWAY; Gerald D.;
(Penngrove, CA) |
Correspondence
Address: |
INTELLECTUAL PROPERTY GROUP;FREDRIKSON & BYRON, P.A.
200 SOUTH SIXTH STREET, SUITE 4000
MINNEAPOLIS
MN
55402
US
|
Assignee: |
THE WALMAN OPTICAL COMPANY
Minneapolis
MN
|
Family ID: |
37679937 |
Appl. No.: |
12/754375 |
Filed: |
April 5, 2010 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11996626 |
Jun 6, 2008 |
|
|
|
PCT/US06/10503 |
Mar 22, 2006 |
|
|
|
12754375 |
|
|
|
|
Current U.S.
Class: |
428/412 ;
427/164; 427/387; 428/447; 522/83 |
Current CPC
Class: |
C08G 59/306 20130101;
C08K 3/36 20130101; Y10T 428/31507 20150401; C09D 163/00 20130101;
C08G 59/3254 20130101; C08K 5/5435 20130101; Y10T 428/31663
20150401; C08L 2666/54 20130101; C09D 163/00 20130101; C09D 183/06
20130101 |
Class at
Publication: |
428/412 ;
428/447; 427/387; 427/164; 522/83 |
International
Class: |
B32B 27/08 20060101
B32B027/08; B05D 3/02 20060101 B05D003/02; B05D 5/06 20060101
B05D005/06; C08K 3/36 20060101 C08K003/36 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 22, 2006 |
US |
PCT/US2006/010503 |
Claims
1. A coating composition for forming a transparent,
abrasion-resistant coating upon a substrate, the composition
comprising: a curable silane based coating composition comprising a
monomeric organofunctional silane, colloidal silica present in an
amount sufficient to improve abrasion resistance as compared to a
composition lacking the colloidal silica, and a cationic
photoinitiator.
2. A composition according to claim 1 wherein the composition
comprises an additional ingredient selected from the group
consisting of the an organofunctional polysiloxane, one or more
polymerizable monomers, and a silane coupling agent.
3. A composition according to claim 2 wherein the composition
comprises both the polysiloxane and a polymerizable monomer.
4. A composition according to claim 2 wherein the composition
comprises both the polysiloxane and a silane coupling agent.
5. A composition according to claim 2 wherein the composition
comprise both a polymerizable monomer and a silane coupling
agent.
6. A composition according to claim 2 wherein the monomers are
selected from the group consisting of ethylenically unsaturated
monomers, non-silane epoxies, oxetanes, alkylalkoxysilanes or
tetraalkoxysilanes, vinyl ethers, and non-silane cycloaliphatic
epoxies.
7. A composition according to claim 2, wherein the silane coupling
agent comprises methyltrimethoxysilane (MTMS).
8. A composition according to claim 1 wherein the composition is
adapted to be cured to provide a coating that exhibit an improved
combination of abrasion-resistance and hardness as compared to a
coating lacking the colloidal silica.
9. A composition according to claim 2 wherein a) the
epoxyfunctional alkoxy silanes of parts A and D are independently
prepared from the group consisting of
glycidoxymethyl-trimethoxysilane, glycidoxymethyltriethoxysilane,
glycidoxymethyl-tripropoxysilane, glycidoxymethyl-tributoxysilane,
.beta.-glycidoxyethyltrimethoxysilane,
.beta.-glycidoxyethyltriethoxysilane,
.beta.-glycidoxyethyl-tripropoxysilane,
.beta.-glycidoxyethyl-tributoxysilane,
.beta.-glycidoxyethyltrimethoxysilane,
.alpha.-glycidoxyethyl-triethoxysilane,
.alpha.-glycidoxyethyl-tripropoxysilane,
.alpha.-glycidoxyethyltributoxysilane,
.gamma.-glycidoxypropyl-trimethoxysilane,
.gamma.-glycidoxypropyl-triethoxysilane,
.gamma.-glycidoxypropyl-tripropoxysilane,
.gamma.-glycidoxypropyltributoxysilane,
.beta.-glycidoxypropyl-trimethoxysilane,
.beta.-glycidoxypropyl-triethoxysilane,
.beta.-glycidoxypropyl-tripropoxysilane,
.beta.-glycidoxypropyltributoxysilane,
.alpha.-glycidoxypropyl-trimethoxysilane,
.alpha.-glycidoxypropyl-triethoxysilane,
.alpha.-glycidoxypropyl-tripropoxysilane,
.alpha.-glycidoxypropyltributoxysilane,
.gamma.-glycidoxybutyl-trimethoxysilane,
.delta.-glycidoxybutyl-triethoxysilane,
.delta.-glycidoxybutyl-tripropoxysilane,
.delta.-glycidoxybutyl-tributoxysilane,
.delta.-glycidoxybutyl-trimethoxysilane,
.gamma.-glycidoxybutyl-triethoxysilane,
.gamma.-glycidoxybutyl-tripropoxysilane,
.gamma.-propoxybutyl-tributoxysilane,
.delta.-glycidoxybutyl-trimethoxysilane,
.delta.-glycidoxybutyl-triethoxysilane,
.delta.-glycidoxybutyl-tripropoxysilane,
.alpha.-glycidoxybutyl-trimethoxysilane,
.alpha.-glycidoxybutyl-triethoxysilane,
.alpha.-glycidoxybutyl-tripropoxysilane,
.alpha.-glycidoxybutyl-tributoxysilane,
(3,4-epoxycyclohexyl)-methyl-trimethoxysilane,
(3,4-epoxycyclohexyl)methyl-triethoxysilane,
(3,4-epoxycyclohexyl)methyl-tripropoxysilane,
(3,4-epoxycyclohexyl)-methyl-tributoxysilane,
(3,4-epoxycyclohexypethyl-trimethoxysilane,
(3,4-epoxycyclohexypethyl-triethoxysilane,
(3,4-epoxycyclohexypethyl-tripropoxysilane,
(3,4-epoxycyclohexyl)-ethyl-tributoxysilane,
(3,4-epoxycyclohexyl)propyl-trimethoxysilane,
(3,4-epoxycyclohexyppropyl-triethoxysilane,
(3,4-epoxycyclohexyl)propyl-tripropoxysilane,
(3,4-epoxycyclohexyl)propyl-tributoxysilane,
(3,4-epoxycyclohexyl)butyl-trimethoxysilane, (3,4-epoxycyclohexy)
butyl-triethoxysilane,
(3,4-epoxycyclohexyl)-butyl-tripropoxysilane, and
(3,4-epoxycyclohexyl)butyl-tributoxysilane.
10. A composition according to claim 9 wherein the composition,
when cured upon a polymeric substrate, provides improved abrasion
resistance as compared to a composition lacking the colloidal
silica.
11. A composition according to claim 1 wherein the composition,
when cured upon a polymeric surface provides an abrasion resistance
(delta haze) of less than about 10%, when determined by Taber
resistance, at 1000 cycles with a 500 g load.
12. A composition according to claim 11 wherein the abrasion
resistance is less than about 5%.
13. A composition according to claim 12 wherein the abrasion
resistance is less than about 2%.
14. A composition according to claim 11 wherein the cured
composition also provides tintability of down to 30% or less as
determined by the spectrophotometric Hazegard system.
15. A composition according to claim 1 wherein the composition
lacks organofunctional polysiloxane and the monomeric silane is
present at a concentration of between about 40% and about 90% by
weight (solids basis) of the composition.
16. A composition according to claim 15 wherein the monomeric
silane is present at a concentration of between about 50% and about
80% by weight (solids basis) of the composition.
17. A composition according to claim 1 wherein the colloidal silica
is present in an amount between about 1% and about 50% by
weight.
18. A composition according to claim 17 wherein the colloidal is
present in an amount between about 20% and about 40% by weight.
19. A composition according to claim 1 wherein the composition
lacks organofunctional polysiloxane and the monomeric silane is
present at a concentration of between about 40% and about 90% by
weight (solids basis) of the composition; the colloidal silica
present in an amount between about 20% and about 40% by weight, and
wherein the composition, when cured upon a polymeric surface
provides an abrasion resistance (delta haze) of less than about 5%,
when determined by Taber resistance.
20. A coating composition for forming a transparent,
abrasion-resistant coating upon a substrate, the composition
comprising: a monomeric organofunctional silane, colloidal silica
present in an amount sufficient to improve abrasion resistance as
compared to a composition lacking the colloidal silica, a cationic
photoinitiator, an organo functional polysiloxane, one or more
polymerizable monomers selected from the group consisting of
ethylenically unsaturated monomers, non-silane epoxies, oxetanes,
alkylalkoxysilanes or tetraalkoxysilanes, vinyl ethers, and
non-silane cycloaliphatic epoxies, and a silane coupling agent
comprising methyltrimethoxysilane (MTMS).
21. A polymeric substrate having cured thereon a composition
according to claim 1.
22. A substrate according to claim 21 wherein the cured composition
provides abrasion resistance (delta haze) of less than about 10%,
when determined by Taber resistance, at 1000 cycles with a 500 g
load.
23. A substrate according to claim 18 wherein the abrasion
resistance is less than about 5%.
24. A substrate according to claim 19 wherein the abrasion
resistance is less than about 2%.
25. A substrate according to claim 21 wherein the substrate itself
comprises unprimed or primed polycarbonate.
26. A substrate according to claim 25 wherein the substrate is in
the form of an optical lens.
27. A method of providing an improved abrasion resistant coating to
a polymeric substrate, the method comprising the steps of providing
a coating composition according to claim 1, and curing the
composition on the surface.
28. A method according to claim 27 wherein the substrate comprises
an optical lens.
29. An optical lens having cured there on a composition according
to claim 1.
Description
TECHNICAL FIELD
[0001] In one aspect, this invention relates to the field of
coatings for transparent objects such as eyeglass lenses, and
refers particularly to coating compositions having low viscosities
and to coating compositions producing highly abrasion resistant
coatings. In another aspect, the invention relates to abrasion
resistant coatings for a wide variety of substrates.
BACKGROUND OF THE INVENTION
[0002] Transparent plastic materials such as eyeglass lenses are
subject to becoming dull and hazy due to scratching and abrasion
during use. Polycarbonate eyeglass lenses, for example, are strong
and shatter resistant but also are relatively soft and susceptible
to scratching. Television screen face plates similarly are made of
flexible, shatter resistant plastic materials such as polycarbonate
and poly (methylmethacrylate), and these also can be scratched or
abraded.
[0003] Various coatings have been proposed for eyeglasses and other
transparent plastic materials to reduce their propensity to become
scratched and abraded. Besides being abrasion resistant, coatings
for eyeglass lenses are often capable of being tinted by treatment
with a dye which becomes incorporated in the coating. As a general
observation, the tintability of a coating tends to decrease as its
hardness and scratch resistance increases, and vice-versa.
[0004] Coating compositions of the type used to provide coatings on
such substrates as polycarbonate eye glass lenses desirably are of
low viscosity. Moreover, as noted earlier, they are also desirably
capable, upon curing, of forming surfaces that on the one hand are
hard and scratch-resistant and on the other hand are tintable, that
is, are capable of readily accepting tinting dyes.
[0005] Applicant has previously described improved coating
compositions that can be used for providing various features. See,
U.S. Pat. Nos. 5,789,082, 5,907,000, 6,100,313, and 6,780,232, the
disclosures of which are incorporated herein by reference. In
particular, U.S. Pat. No. 6,780,232 describes a composition that
includes the use of both hydrolyzed and partially hydrolyzed
silanes, though the composition itself is described as being
preferably free of silica and other colloids.
[0006] See also U.S. Pat. No. 4,486,504 (assigned to GE) which
describes an ultraviolet radiation-curable silicone coating
composition which, when applied to a solid substrate, is said to
provide an abrasion-resistant coating firmly adhered thereon. The
silicone coating composition is said to be free of residual solvent
and free of toxic hydroxy acrylates, and prepared from the
hydrolysis products of acryloxy-functional silanes and/or
glycidoxy-functional silanes, colloidal silica and a
photoinitiator.
[0007] See also, U.S. Pat. No. 5,385,955 (assigned to Essilor)
which describes a thermally cured coating composition for
ophthalmic lens which comprises a mixture of a monoepoxysilane,
colloidal silica, an alkylalkoxysilane or tetraalkoxysilane, and an
ultraviolet activated photoinitiator capable of initiating a
cationic cure of such composition. The photoinitiator is an
aromatic onium salt or an iron arene salt complex.
[0008] Finally, see WO 97/45498 (Ho, et al.) which describes what
are described as being highly tintable, abrasion resistant coatings
prepared from compositions that comprise a base resin that does not
contain non-silylated acrylate monomer, a tint-enhancing quantity
of a quaternary ammonium sale, and a crosslinking agent.
[0009] What is clearly needed is are compositions suitable for use
on materials such as transparent polymeric substrates, including
the front side of eyeglass lenses, though having abrasion
resistance that is at least as good as, if not significantly better
than that provided by compositions currently available or
previously described.
SUMMARY OF THE INVENTION
[0010] The present invention provides coating compositions having
desirable viscosity yet yielding cured coatings that exhibit
excellent abrasion-resistance and hardness. The compositions
preferably are of low viscosity and most preferably are
substantially free of volatile solvents. Preferred compositions of
this invention can be used on polymeric substrates such as those
used to prepare optical lenses, including either the front or rear
surfaces, or both, in a manner that meets or exceeds the stringent
requirements for such use.
[0011] In one embodiment, the present invention provides a curable
silane based coating composition that comprises both a monomeric
organofunctional silane in combination with colloidal silica in
amounts sufficient to provide an optimal combination of coating
viscosity and cured abrasion resistance as compared to a coating
composition lacking either or both component. Moreover, Applicant
has discovered, inter alia, that such a coating composition can be
provided in the form of a solvent free system that can include
various additional ingredients as well. Examples of such additional
ingredients include, but are not limited to, organofunctional
polysiloxanes, polymerizable monomers and/or silane coupling
agents.
[0012] An exemplary and preferred composition of this invention
therefore comprises a curable silane system that comprises a
cationic initator together with monomeric organofunctional silane
and colloidal silica. More preferably, the system comprises an
organofunctional polysiloxane or a silane coupling agent, or both.
In alternative and preferred situations, the system comprises as
well one or more polymerizable monomers.
[0013] In a particularly preferred embodiment for use on optical
lenses, the present invention provides a coating composition for
forming a transparent, abrasion-resistant coating upon a substrate,
the composition comprising:
[0014] A. an organofunctional polysiloxane (e.g., the hydrolysis
product of an epoxy functional alkoxy silane),
[0015] B. a curing agent comprising a cationic photoinitiator for
polymerizing epoxy compounds,
[0016] C. a monomeric organofuncitonal silane, e.g., a silanol free
epoxy functional silane, and
[0017] D. colloidal silica present in an amount sufficient to
improve abrasion resistance as compared to a composition lacking
the colloidal silica.
[0018] Optionally, and preferably, the composition further
comprises one or more monomeric components. Preferred monomeric
components are adapted to permit the formation of an
interpenetrating network. In such an embodiment, the composition
preferably comprises:
[0019] E. a polymerizable monomer (and corresponding initiators
where need be) selected from the group consisting of one or more of
the following, including combinations thereof: [0020] 1.
ethylenically unsaturated monomers (e.g., vinyls, (meth)acrylates)
[0021] 2. non-silane epoxies (e.g., epoxy ethers) [0022] 3.
oxetanes [0023] 4. alkylalkoxysilanes and/or tetraalkoxysilanes)
[0024] 5. vinyl ethers [0025] 6. non-silane cycloaliphatic
epoxies
[0026] Also optionally, the composition further comprises:
[0027] F. a silane coupling agent, preferably comprising
methyltrimethoxysilane (MTMS).
[0028] Compositions of this invention can be prepared in any
suitable manner. For instance, the above composition can be
prepared by providing and blending together parts A, C and D,
typically followed by distillation to remove solvents, after which
cationic initiator B can be incorporated and the composition can be
photocured. For instance, a preferred method of preparing the
composition includes:
[0029] 1) hydrolysis of an epoxyalkoxysilane, after which volatile
solvents are stripped under vacuum (e.g., at 25-100 C);
[0030] 2) providing colloidal silica in an alcohol solution,
adjusting the pH to about 7.5-8 and treating the solution with
alkoxysilane and water at 25-75 C to produce a colloidal
silica-alkoxy siloxane reaction product;
[0031] 3) mixing the reaction products from steps 1) and 2) with
unhydrolyzed epoxyalkoxysilane, and removing volatiles under vacuum
at 50-80 C, and
[0032] 4) mixing the reaction product from step 3) with
photoiniators and flow control agents, and optionally also with
various desired diluents, such as acrylic monomers, non-silane
epoxies, vinyl ethers, oxetanes or combinations thereof.
[0033] The ethylenically unsaturated monomer(s), when present and
in the form of preferred monomer of component E, preferably
comprises an acrylic monomer, and more preferably an acrylic
monomer having an acrylic functionality of not more than two.
Inclusion of a monomeric (silanol free) epoxy functional silane in
the coating composition enables a substantial reduction in the
viscosity of the composition to be achieved, without loss of
abrasion resistance. Amounts of the monomeric silane sufficient to
significantly reduce viscosity of the coating composition up to
about 50% by weight, solids basis, can be used as well.
[0034] Compositions of this invention are particularly well suited
for polymeric substrates, and particularly high refractive index
substrates intended for optical applications, including
thermosetting and thermoplastic polycarbonates, as well as
polyurethanes. Such substrates can be used for a variety of
applications, including for automotive instrumentation, aviation
gauges and instruments, display and/or shielding windows, eyewear
lenses, handheld meters and devices, molded display windows and
panels, outdoor equipment gauges and displays, test &
laboratory instrument displays, screen printing POP signage,
thermoformed displays, medical displays and panels, and video and
LED filters.
[0035] Applicants have discovered the manner in which both
viscosity and abrasion resistance can be improved, while optionally
providing good tintability as well.
DETAILED DESCRIPTION
[0036] Compositions of this invention provide improved properties
as compared to compositions previously described for use in coating
polymeric surfaces, and particularly polymeric optical lenses. In
particular, the present compositions provide improved abrasion
resistance. For use on optical lenses, for instance, preferred
compositions of this invention can be used to provide "delta haze"
(i.e., change in haze) values (at 1000 cycles using a 500 g load)
of on the order of less than about 10%, preferably less than about
5%, and even more preferably less than about 2%, as determined in
the manner described in the Examples below.
[0037] In addition to such improved abrasion resistance, preferred
compositions can provide acceptable tintability, e.g., preferably
down to 30% transmission or less, more preferably down to 20%
transmission or less, and even more preferably down to 17% or less
(e.g., after immersion in a dye bath for 15 minutes as described in
Example 2 below, and determined using spectrophotometric Hazegard
system (XL-211) available from BYK Gardner).
[0038] In contrast, comparative examples are provided below to
demonstrate that compositions having components A, B and C above,
together with polymerizable monomers (equivalent to components E2
and E5 above), but lacking colloidal silica of the present
invention, provide increased tintability, but haze values of on the
order of 11.3 to 11.6 (comparative example 2), and 9.4 to 9.8
(comparative example 3).
[0039] Also by comparison, compositions such as those described in
above-captioned U.S. Pat. No. 5,221,560 (Perkins, et al.) are said
to provide Taber abrasion values of 6.4 (Perkins et al., Example 4)
and 7 (Perkins, et al., Example 7), using CS-10F wheels (which are
softer than those exemplified below). The exemplified compositions
do not include a silane monomer of the type presently described and
claimed, but do include SiO.sub.2 concentrations that can be
calculated as 22.5% weight concentration (solids basis). Moreover,
and in further contrast to compositions of the present invention,
the compositions described in the '560 patent are prepared in a
manner that includes solvents.
[0040] By further comparison, General Electric's U.S. Pat. No.
4,348,462 exemplifies compositions that provide haze values of 1.7
to 2.6, based on compositions that include SiO.sub.2 concentrations
that can be calculated as 24.85% weight concentration (solids
basis), but that again do not include silane monomers of the
present invention. The '462 patent itself also describes the manner
in which compositions that contain non-silyl acrylates are known to
be hazardous and dangerous to work with.
[0041] The ingredients used in preparing compositions of the
present invention can include the following.
[0042] A. Organfunctional polysiloxane, preferably in the form of
the hydrolyzed or partially hydrolyzed product of an epoxy
functional alkoxysilane
[0043] In coating compositions of the invention, the epoxy
functional alkoxy silane precursor of such a (partially) hydrolyzed
polymerizable ingredient is preferably an epoxyalkylalkoxysilane of
the following structure:
Q--R.sub.1--Si(R.sub.2).sub.m-- (OR.sub.3).sub.3-m
wherein R.sub.1 is a C.sub.1-C.sub.14 alkylene group, R.sub.2 and
R.sub.3 independently are C.sub.1-C.sub.4 alkyl groups, Q is a
glycidoxy or epoxycyclohexyl group, and m is 0 or 1. The alkoxy
groups are at least partially hydrolyzed to form silanol groups
with the release of the R.sub.3OH alcohol, and some condensation of
the silanol groups occurs. Epoxy reactivity is preserved,
however.
[0044] Many epoxy functional alkoxysilanes are suitable as
hydrolysis precursors, including glycidoxymethyl-trimethoxysilane,
glycidoxymethyltriethoxysilane, glycidoxymethyl-tripropoxysilane,
glycidoxymethyl-tributoxysilane,
.beta.-glycidoxyethyltrimethoxysilane,
.beta.-glycidoxyethyltriethoxysilane,
.beta.-glycidoxyethyl-tripropoxysilane,
.beta.-glycidoxyethyl-tributoxysilane,
.beta.-glycidoxyethyltrimethoxysilane,
.alpha.-glycidoxyethyl-triethoxysilane,
.alpha.-glycidoxyethyl-tripropoxysilane,
.alpha.-glycidoxyethyltributoxysilane,
.gamma.-glycidoxypropyl-trimethoxysilane,
.gamma.-glycidoxypropyl-triethoxysilane,
.gamma.-glycidoxypropyl-tripropoxysilane,
.gamma.-glycidoxypropyltributoxysilane,
.beta.-glycidoxypropyl-trimethoxysilane,
.beta.-glycidoxypropyl-triethoxysilane,
.beta.-glycidoxypropyl-tripropoxysilane,
.beta.-glycidoxypropyltributoxysilane,
.alpha.-glycidoxypropyl-trimethoxysilane,
.alpha.-glycidoxypropyl-triethoxysilane,
.alpha.-glycidoxypropyl-tripropoxysilane,
.alpha.-glycidoxypropyltributoxysilane,
.gamma.-glycidoxybutyl-trimethoxysilane,
.delta.-glycidoxybutyl-triethoxysilane,
.delta.-glycidoxybutyl-tripropoxysilane,
.delta.-glycidoxybutyl-tributoxysilane,
.delta.-glycidoxybutyl-trimethoxysilane,
.gamma.-glycidoxybutyl-triethoxysilane,
.gamma.-glycidoxybutyl-tripropoxysilane,
.gamma.-propoxybutyl-tributoxysilane,
.delta.-glycidoxybutyl-trimethoxysilane,
.delta.-glycidoxybutyl-triethoxysilane,
.delta.-glycidoxybutyl-tripropoxysilane,
.alpha.-glycidoxybutyl-trimethoxysilane,
.alpha.-glycidoxybutyl-triethoxysilane,
.alpha.-glycidoxybutyl-tripropoxysilane,
.alpha.-glycidoxybutyl-tributoxysilane,
(3,4-epoxycyclohexyl)-methyl-trimethoxysilane,
(3,4-epoxycyclohexyl)methyl-triethoxysilane,
(3,4-epoxycyclohexyl)methyl-tripropoxysilane,
(3,4-epoxycyclohexyl)-methyl-tributoxysilane,
(3,4-epoxycyclohexyl)ethyl-trimethoxysilane,
(3,4-epoxycyclohexyl)ethyl-triethoxysilane,
(3,4-epoxycyclohexyl)ethyl-tripropoxysilane,
(3,4-epoxycyclohexyl)-ethyl-tributoxysilane,
(3,4-epoxycyclohexyl)propyl-trimethoxysilane,
(3,4-epoxycyclohexyl)propyl-triethoxysilane,
(3,4-epoxycyclohexyl)propyl-tripropoxysilane,
(3,4-epoxycyclohexyl)propyl-tributoxysilane,
(3,4-epoxycyclohexyl)butyl-trimethoxysilane, (3,4-epoxycyclohexy)
butyl-triethoxysilane,
(3,4-epoxycyclohexyl)-butyl-tripropoxysilane, and
(3,4-epoxycyclohexyl)butyl-tributoxysilane. A particularly
preferred epoxyalkylalkoxysilane is .gamma.-glicidoxypropyl
trimethoxy silane due to its wide commercial availability.
[0045] Hydrolysis of the epoxy functional alkoxysilane precursor
may occur in an acidic environment, and reference is made to U.S.
Pat. No. 4,378,250, the teachings of which are incorporated herein
by reference. Hydrolysis of the alkoxy groups liberates the
associated alcohol (which may be stripped off) to form silanol
groups, which in turn are relatively unstable and tend to condense
spontaneously. Hydrolysis of the alkoxysilane can be complete or
incomplete, and preferably, the alkoxysilane is reacted with a
stoichiometricly sufficient quantity of water to hydrolyze at least
50% of the alkoxy groups and most preferably from about 60% to
about 70% of the alkoxy groups. For the hydrolysis of an epoxy
functional trialkoxy silane, good results have been obtained by
reacting the silane with a stoichiometricly sufficient quantity of
water to hydrolyze two-thirds of the alkoxy groups.
[0046] If present, the (partially) hydrolyzed epoxy functional
silane component is present in the coating compositions of the
invention at a weight concentration of about 10% to about 75%, and
preferably about 20% to about 50%. Unless otherwise indicated, the
concentration of ingredients in the present composition is
described as a percentage (solids basis) based on the weight of the
overall composition. Those skilled in the art, given the present
description, will appreciate the manner in which both the actual
amounts of the organofunctional polysiloxane and monomeric silane,
as well as their relative amounts, can be considered and controlled
to provide varying desired properties.
B. Cationic Initiator
[0047] Useful cationic initiators for the purposes of this
invention include the aromatic onium salts, including salts of
Group Va elements, such as phosphonium salts, e.g., triphenyl
phenacylphosphonium hexafluorophosphate, salts of Group VIa
elements, such as sulfonium salts, e.g., triphenylsulfonium
tetrafluoroborate, triphenylsulfonium hexafluorophosphate and
triphenylsulfonium hexafluoroantimonate, and salts of Group VIIa
elements, such as iodonium salts such as diphenyliodonium chloride
and diaryl iodonium hexafluoroantimonate, the latter being
preferred. The aromatic onium salts and their use as cationic
initiators in the polymerization of epoxy compounds are described
in detail in U.S. Pat. No. 4,058,401, "Photocurable Compositions
Containing Group VIA Aromatic Onium Salts," by J. V. Crivello
issued Nov. 15, 1977; U.S. Pat. No. 4,069,055, "Photocurable Epoxy
Compositions Containing Group VA Onium Salts," by J. V. Crivello
issued Jan. 17, 1978, U.S. Pat. No. 4,101,513, "Catalyst For
Condensation Of Hydrolyzable Silanes And Storage Stable
Compositions Thereof," by F. J. Fox et al. issued Jul. 18, 1978;
and U.S. Pat. No. 4,161,478, "Photoinitiators," by J. V. Crivello
issued Jul. 17, 1979, the disclosures of which are incorporated
herein by reference.
[0048] Other cationic initiators can also be used in addition to
those referred to above; for example, the phenyldiazonium
hexafluorophosphates containing alkoxy or benzyloxy radicals as
substituents on the phenyl radical as described in U.S. Pat. No.
4,000,115, "Photopolymerization Of Epoxides," by Sanford S. Jacobs
issued Dec. 28, 1976, the disclosure of which is incorporated
herein by reference. Preferred cationic initiators for use in the
compositions of this invention are the salts of Group VIa elements
and especially the sulfonium salts, and also the Group VIIa
elements, particularly the diaryl iodonium hexafluororantimonates.
Particular cationic catalysts include diphenyl iodonium salts of
tetrafluoro borate, hexafluoro phosphate, hexafluoro arsenate, and
hexafluoro antimonate; and triphenyl sulfonium salts of
tetrafluoroborate, hexafluoro phosphate, hexafluoro arsenate, and
hexafluoro antimonate.
C. Monomeric Organofunctional Silane
[0049] The composition of this invention further comprises a
monomeric organofunctional silane, and more preferably a monomeric
(silanol free) epoxy functional silane, which can also be referred
to as an unhydrolyzed epoxy functional alkoxy silane. In turn,
certain preferred compositions can include both hydrolyzed and
unhydrolyzed epoxy functional alkoxy silanes, with the latter being
present in an amount sufficient to reduce the viscosity of the
composition itself. It is noted that, while the "hydrolysis
product" of such a silane can certainly include compounds that are
themselves partially hydrolyzed (depending on the mole ratio of
water to alkoxy groups as described herein), whereas an
unhydrolyzed silane of the sort claimed is clearly one that is
prepared and used in the substantial absence of water. As described
herein, water is removed from the hydrolysis product component,
prior to the addition of an unhydrolyzed component, in order to
permit the latter to retain its unhydrolyzed nature. See, for
instance, the examples below in which the partially hydrolyzed
component is stripped of volatiles (including water) prior to being
combined with the unhydrolyzed component. Hence, when and to the
extent "partially hydrolyzed" silanes might be discussed in the
art, these compounds tend to be different than, and not at all
suggestive of the use of both hydrolyzed and unhydrolyzed silane
components as presently described.
[0050] In turn, the composition desirably includes an effective
amount up of a suitable non-hydrolyzed epoxy functional alkoxy
silane, including those selected from the silanes listed above.
When used in combination with an organofunctional polysiloxane, the
non-hydrolyzed epoxy functional alkoxy silane desirably is present
in an amount not less than about 10%, preferably at least about
20%, and most preferably from about 40% to about 50% by weight,
solids basis. Preferably, the epoxy functional alkoxy silane that
is included as the non-hydrolyzed component also is of the same or
similar type as that employed to make the hydrolyzed component. It
should be understood that the hydrolyzed and non-hydrolyzed
components may be different and each may utilize one or a blend of
different epoxy functional alkoxy silanes, as desired.
[0051] When used in a composition that lacks an organofunctional
polysiloxane, the monomeric silane can be used at an amount of at
least 10%, preferably between about 40% and about 90%, and more
preferably between about 50% and 80%
D. Colloidal Silica
[0052] The colloidal silica component of the present composition
can be provided in any suitable form. Suitable colloidal silicas
for use in a composition of this invention provide an optimal
combination of such properties as size, uniformity, availability
and cost, and are generally provided in the form of a silicon
dioxide (SiO.sub.2) dispersed in solvents (e.g., alcohols).
Colloidal silica is available in basic or acidic form. Either may
be utilized; however, the acidic form (low sodium content) is
preferred.
[0053] Examples of suitable silicas are commercially available, for
instance as the organosilicasol line available from Nissan Chemical
Industries, Inc. (Osaka JP), including types "MA-ST" and "IPA-ST",
both containing SiO.sub.2 (30 wt %, 0.01 microns), dispersed in
methanol and isopropanol, respectively. Such silicas are available
in a variety of size ranges, and most preferably are used in a
range of about nanometers to about 20 nanometers.
[0054] Colloidal silica is preferably used in a final amount
sufficient to improve abrasion resistance as compared to a
composition lacking the silica. In some preferred embodiments, the
colloidal silica can be used in an amount between about 1% and
about 50% by weight, based on the weight of the final composition,
preferably between about 2% and about 30% and more preferably
between about 5% and about 20%. In other preferred embodiments, the
colloidal silica can be used in amount between about 1% and about
50%, and more preferably between about 20% and about 40%.
[0055] In turn, the abrasion resistance (delta haze) of a
composition of this invention is preferably less than about 10%
(when determined by Taber resistance, at 1000 cycles with a 500 g
load), more preferably less than about 5%, and most preferably less
than about 2%. By comparison, compositions lacking the colloidal
silica generally provide abrasion resistant in the range of about
10% to about 20% or more. The abrasion resistance of a composition
of this invention also compares quite favorably with commercial
coating compositions such as those sold under the Ultra Optics
Product Nos. UV200 and UV-NV.
E. Polymerizable Monomer
[0056] 1. Ethylenically Unsaturated Monomers (e.g., Vinyls,
(Meth)Acrylates)
[0057] A wide variety of ethylenically unsaturated monomers
(including oligomers) can be employed in the coating composition of
the invention, and acrylic monomers and oligomers, particularly
those having acrylic functionalities of not greater than two, are
preferred. Useful acrylic compounds for improving adhesion to
polycarbonate substrates include both mono and di-functional
monomers, but other or additional polyfunctional acrylic monomers
may also be included.
[0058] Examples of monofunctional acrylic monomers include acrylic
and methacrylic esters such as ethyl acrylate, butyl acrylate,
2-hydroxypropyl acrylate, cyclohexyl acrylate, 2-ethylhexyl
acrylate, methyl methacrylate, ethyl methacrylate, and the like.
Examples of polyfunctional acrylic monomers, including both
difunctional and tri and tetrafunctional monomers, include
neopentylglycol diacrylate, pentaerythritol triacrylate,
1,6-hexanediol diacrylate, trimethylolpropane triacrylate,
tetraethylene glycol diacrylate, 1,3-butylene glycol diacrylate,
trimethylolpropane trimethacrylate, 1,3-butylene glycol
dimethacrylate, ethylene glycol dimethacrylate, pentaerythritol
tetraacrylate, tetraethylene glycol dimethacrylate, 1,6-hexanediol
dimethacrylate, ethylene glycol diacrylate, diethylene glycol
diacrylate, glycerol diacrylate, glycerol triacrylate,
1,3-propanediol diacrylate, 1,3-propanediol dimethacrylate,
1,2,4-butanetriol trimethacrylate, 1,4-cyclohexanediol diacrylate,
1,4-cyclohexanediol dimethacrylate, pentaerythritol diacrylate,
1,5-pentanediol dimethacrylate, and the like. The
acrylic-functional monomers and oligomers desirably are employed at
a weight concentration of at least about 10% by weight, preferably
from about 10% to about 50%, and most preferably from about 10% to
about 25%, all on a solids basis.
[0059] As initiators for the ethylenically unsaturated monomers,
photoactivated free-radical initiator are preferred, although
thermally activated free radical initiators may also be used.
Useful photoinitiators for this purpose are the haloalkylated
aromatic ketones, chloromethylbenzophenones, certain benzoin
ethers, certain acetophenone derivatives such as
diethoxyacetophenone and 2-hydroxy-2-methyl-1-phenylpropan-1-one. A
preferred class of free-radical photoinitiators is the benzil
ketals, which produce rapid cures. Suitable photoinitiators include
.alpha.,.alpha.-dimethoxy-.alpha.-phenyl acetophenone
(Iragacure.TM. 651), and 2-hydroxy-2-methyl-1-phenylpropane-1-one
(Darocure.TM. 1173, Ciba-Geigy Corporation). A preferred
photoiniator is 1-hydroxycyclohexyl phenyl ketone (available as
Irgacure 184). Specific examples of photoinitiators include ethyl
benzoin ether, isopropyl benzoin ether, dimethoxyphenyl
acetophenone, diethoxy acetophenone, and benzophenone. Other
examples of suitable initiators are diethoxy acetophenone ("DEAP",
First Chemical Corporation) and 1-benzoyl-1-hydroxycyclohexane
("Irgacure 184", Ciba Geigy).
[0060] E.2-5 Polyermizable monomers of this invention can be used
in any suitable amount, e.g., between about 10% and about 50% and
more preferably between about 10 and about 25%. Examples of
suitable monomers of the remaining types E2-E5 include, but are not
limited to the following:
[0061] E2. non-silane epoxies (e.g., epoxy ethers), including
aliphatic polyol polyepoxy resins such as those sold under the
tradename "Heloxy Modifier 48" and available from Resolution
Peformance Products (Houston, Tex.).
[0062] E3. oxetanes--di[1-ethyl(3-oxetanyl)]methyl ether, produced
as "OXT-221" by Toagosei Co. Ltd.
[0063] E4. alkylalkoxysilanes or tetraalkoxysilanes, such as
tetraethoxysilane (also known as silicon tetraethoxide,
tetraethylorthosilicate, and tetraethyl silicate), as available
from Gelest, Inc. (Morrisville, Pa.).
[0064] E5. vinyl ethers such as 1,3-benzenedicarboxylic acid,
bis-[4-(ethenyloxyl)butyl]ester, Bis(4-vinyloxybutyl)isophthalate
(available as Vectomer 4010 Vinyl Ether from Morflex, Inc.) and the
divinyl ether of 1,4 cyclohexane dimethanol (available as
"Rapi-Cure CHVE" from ISP(Canada), Inc.
[0065] E6. non-silane cycloaliphatic epoxies, including
cycloaliphatic epoxide resins such as those sold under the
tradename Uvacure, such as Uvacure 1502 included within the Radcure
line of resins available from UCB Group.
F. Silane Coupling Agent
[0066] In a further, and preferred embodiment, the composition of
this invention optionally also includes the use of a silane
coupling agent. The use of such an agent provides desirable
properties, particularly in terms of increased compatability of the
silicone component with the remaining composition.
[0067] Suitable silane coupling agents provide an optimal
combination of such properties as compatability, low viscosity
(e.g., liquid at room temperature), the ability to improve adhesive
and/or flexibility characteristics without undue impact on hardness
or abrasion resistance, and the ability to react in a composition
of this invention to provide a clear cured composition.
[0068] Examples of suitable silane coupling agents include, but are
not limited to the following, available from AP Resources Company:
Methyltrimethoxysilane (MTMS); Tetraethoxysilane (TEOS);
Tetramethoxysilane (TMOS); Vinyltriethoxysilane; and
Vinyltrimethoxysilane. Silane coupling agents can be used in amount
of between about 1% and about 10%, and more preferable between
about 3% and about 7%, based on the weight of the composition.
Optional Surfactants:
[0069] Other optional ingredients include polyalkylene oxide
modified polydimethylsiloxanes, which by way of example, may have
the formula:
Me.sub.3SiO(Me.sub.2SiO).sub.x[MeSi(PE)O].sub.ySiMe.sub.3
where Me is methyl and PE is
--(CH.sub.2).sub.3O(EO).sub.m(PO).sub.nZ. Here, These surfactants
are referred to as "AP" (alkyl-pendant) types. Other polyalkylene
oxide modified siloxanes may have the general formula
(MeSi).sub.y-2[(OSiMe.sub.2).sub.x/yO--PE].sub.y, where PE is
(EO).sub.m(PO).sub.nR, R being lower alkyl. The latter surfactants
are referred to as the "AEB" (alkoxy endblocked) typeIn these
general formulas, EO represents ethyleneoxy, PO represents
1,2-propyleneoxy, Z is H or lower alkyl, and x, y, m and n can vary
as desired.
[0070] A series of polyalkylene oxide modified siloxane surfactants
as thus described are available from Witco Corporation under its
registered trademark SILWET. Alkoxypolyalkylene oxyethanols, and
the substituted polyglycols such as nonylphenol polyethylene
glycol, are generally available from Union Carbide Corporation
under its registered trademark TERGITOL.
[0071] The amount of surfactant to be used in a coating composition
is the amount which provides the desired tintability to cured
coatings derived from the composition, and this amount may range
from a minimum amount--usually a percent or two by weight--that
provides noticeable improvement in tintability up to about 10% by
weight or more. Amounts of surfactant in the range of about 1% to
about 10% by weight of the composition are usually appropriate, and
surfactant concentrations of about 4% have given good results.
[0072] The invention may be more readily understood by reference to
the following illustrative, non-limiting examples. In these
examples, tintability is measured as follows: A coated and cured
sample is immersed in BPI Black Dye (Brain Power Inc.) at
95.degree. C.-100.degree. C. for 15 minutes and then rinsed with
water and dried. The transmissivity T of the sample is measured
spectrophotometrically, and tintability is reported as percentage
transmissivity. Resistance to abrasion may be measured by abrading
the coated surface of a transparent substrate under predetermined
conditions and measuring the haze that is formed as a reduction in
light transmissivity. One such testing apparatus is referred to as
a Taber Abrader, a product of Byk-Gardner. Abrasion resistance
testing with this equipment may be performed in accordance with
ASTM D 1044-2005. The particular equipment employed for testing
coatings referred to below involved a model 5130 Taber abrader
equipped with a CS10 abrasive wheel weighted at 500 grams.
[0073] The invention will be further described by reference to the
following, non-limiting Examples.
EXAMPLES
Comparative Example 1
Preparation of Epoxy Base Compositions
[0074] Epoxy base #1: A partially hydrolyzed epoxy-functional
alkoxysilane is prepared by combining 236 g. of
.gamma.-glycidoxypropyltrimethoxysilane, 36 g of water and 0.5 ml
of a 1% HCl solution and mixing for 16-20 hours. The resulting
product is stripped of volatiles under vacuum.
[0075] Epoxy base #2: A second partially hydrolyzed
epoxy-functional alkoxysilane is prepared by combining 246 g of
epoxy cyclohexylethyltrimethoxysilane, 18 g of water, 20 g of
ethanol and 0.2 g of an acidic functional ion exchange resin (CT
275, Purolite Corp.). The mixture is stirred at room temperature
for 36-40 hours, and then is stripped of volatiles under
vacuum.
Comparative Example 2
[0076] Two coating compositions, labeled A and B, were prepared by
blending together the following ingredients, amounts being given in
grams. The viscosity of the compositions were measured and
compositions were coated on polycarbonate lenses and UV cured using
a medium pressure mercury bulb, 250 watts/inch. The coated lenses
were subjected to the Taber Abrasion test described above.
TABLE-US-00001 Ingredient A B Butane diol diacrylate 8.0 8.0
Cyclohexane dimethanol divinylether 2.0 2.0 Trimethylolpropane
triglycidyl ether 7.5 7.5 Epoxy base #1 9.5 5.5
.gamma.-glycidoxypropyltrimethoxysilane 0.0 5.0 (not hydrolyzed)
Triarylsulfonium hexafluorphosphate 0.64 0.66 (Cyracure 6990, Union
Carbide) Triarylsulfonium hexafluoroantimonate 0.64 0.64 (Cyracure
6974, Union Carbide) 2-hydroxy-2-methyl-1-phenyl propan-1-one 0.8
0.8 (Darocure1173, Ciba-Geigy Corporation) Ebecryl 350 (silicone
flow control agent, 0.4 0.4 UCB Chemicals Corp.), Viscosity, cps 32
11 Taber abrasion, % haze, 200 cycles 11.3-11.6 11.3-11.4 Note
should be made that the viscosity of Composition B was
approximately one-third the viscosity of comparative Composition
A
Comparative Example 3
[0077] Three coating compositions, labeled C, D and E, were
prepared by blending together the following ingredients, amounts
being given in grams. The viscosity of the compositions were
measured and compositions were coated, cured and tested as in
Example 2.
TABLE-US-00002 Ingredient C D E Epoxy base #1 7.6 7.6 7.6 Hexane
diol diacrylate 6.4 5.2 6.4 Cyclohexane dimethanol divinylether 1.6
1.6 1.6 Epoxy cyclohexylethyl trimethoxy silane 6.0 2.0 4.0
(monomeric) Epoxy base #2 0.0 4.0 2.0 1/1 mix of benzophenone and
1-hydroxy 0.6 0.5 0.6 cyclohexylphenyl ketone Mixed
Triarylsulfonium Hexafluoroantimonate 1.2 1.2 1.2 salts, 50% in
Propylene Carbonate (UVI 6974, Union Carbide) Ebecryl 350 0.2 0.2
0.2 Viscosity, cps 12.0 26 22 Taber abrasion, 200 cycles, % haze
9.8 9.4 9.6
Comparative Example 4
[0078] A base composition was prepared by blending the following
ingredients, amounts being given in grams:
TABLE-US-00003 Glycidoxypropyltrimethoxysilane, partially
hydrolyzed as 36 in Example 1 Glycidoxypropyltrimethoxysilane,
unhydrolyzed 50 Hexane diol diacrylate 15 Pentaerythritol
triacrylate 5.0 1/1 mix of benzophenone and 1-hydroxy 1.8
cyclohexylphenyl ketone Diaryliodonium hexafluorophosphate (CD
1012, Sartomer Corp) 4.0
[0079] The resulting base composition was divided into 10 g
aliquots, and to each aliquot was added 0.4 g of one of the
surfactants listed below, and the compositions were spin-coated on
polycarbonate lenses and cured under UV light to form coating
thicknesses in the range of 8 to 10 microns. The tintability of
each lens was measured as described above.
TABLE-US-00004 Water Tintability Surfactant Solubility (% T) SILWET
L-77 (polyalkylene oxide- Dispersible 27.7 modified
heptamethyltrisiloxane, 700 mol. wt., AP type) SILWET L-722
(polyalkylene oxide- Insoluble 26.2 modified dimethylsiloxane, 3000
mol. wt., AEB type) SILWET L-7001 (polyalkylene oxide- Partially
26.2 modified dimethylsiloxane, 20,000 mol. soluble wt., AP type)
SILWET L-7500 (polyalkylene oxide- Partially 35.4 modified
dimethylsiloxane, 3,000 mol. wt., soluble AP type) SILWET L-7604
(polyalkylene oxide- Soluble 26.4 modified dimethylsiloxane, 4,000
mol. wt., AP type) SILWET L-7607 (polyalkylene oxide- Soluble 27.7
modified dimethylsiloxane, 1,000 mol. wt., AP type) SILWET L-7607
(polyalkylene oxide- Insoluble 29.4 modified dimethylsiloxane,
10,000 mol. wt., AP type) TERGITOL S-3 Insoluble 26.4
(alkyloxypolyethyleneoxyethanol, mol. wt. 332) TERGITOL S-5
Dispersible 28.4 (alkyloxypolyethyleneoxyethanol, mol. wt. 420)
TERGITOL S-7 Soluble 29.0 (alkyloxypolyethyleneoxyethanol, mol. wt.
508) TERGITOL NP-4 (nonylphenol Insoluble 27.0 polyethylene glycol
ether, mol. wt. 396) TERGITOL NP-6 (nonylphenol Dispersible 33.5
polyethylene glycol ether, mol. wt. 484) TERGITOL NP-6 (nonylphenol
Dispersible 27.9 polyethylene glycol ether, mol. wt. 528) TERGITOL
NP-15 (nonylphenol Soluble 27.3 polyethylene glycol ether, mol. wt.
880)
[0080] While preferred embodiments of the invention have been
described, it should be understood that various changes,
adaptations and modifications may be made therein without departing
from the spirit of the invention or the scope of the appended
claims.
Working Examples 1-10
TABLE-US-00005 [0081] INGREDIENTS KEY (product name, chemical
description, source): A187 Glycidoxy propyl trimethoxy silane (GE
Silicones) A186 Epoxy Cyclohexyl Trimethoxy Silane (GE Silicones) A
1630 Methyl trimethoxy silane (Crompton Corp) SR 9209 alkoxylated
aliphatic diacrylate (Sartomer, Inc.) SR 444 pentaerythritol
triacrylate (Sartomer, Inc.) SR-351 trimethylolpropane triacrylate
(TMPTA, Sartomer, Inc.) SR-238 1,6 hexanediol diacrylate (HDODA,
Sartomer, Inc.) DEAP 2,2-diethoxy acetophenone, free radical
initiator (First Chemical Corporation) Cyracure 6974 Cationic
photoiniator (Dow Chemical) Irgacure 184 Free radical photoiniator
(Ciba Geigy) Irgacure 250 Cationic photoiniator (Ciba Geigy)
Uvacure 1502 Cycloaliphatic epoxy resin (UCB Chemicals Corp)
Cyracure 3-Ethyl-3-(hydroxymethyl)oxetane (Dow Chemical) UVR 6000
OXT-221 bis[1-ethyl(3-oxetanyl)]methyl ether (Toagosei, Ltd) BYK
307 Silicone type flow control agent (BYK-Chemie) MA-ST 30%
Colloidal silica in methyl alcohol (Nissan Chemical) Vectomer Vinyl
ether (Morton Chemical) Heloxy aliphatic polyol polyepoxy resin
(Revolution Modifier 48 Performance)
Example 1
Preparation of Base Resin (Epoxy Functional Inorganic/Organic
Hybrid)
[0082] The following ingredients were mixed with stirring for
either 2 hours at 50-60 C or for 18-20 hrs at room temperature in a
flask equipped with a condenser, after which volatiles were removed
under reduced pressure to provide a stripped, hydrolyzed silane
component as "Resin A".
TABLE-US-00006 Resin A Ingredient Amount (g) Non-hydrolyzed silane
1000 (A187) H.sub.20 141 10% HCl 5.4
[0083] A second composition (Resin B) was prepared to provide
silane treated colloidal silica, by mixing colloidal silica and
silane in a flask fitted with a condenser for 18-20 hrs at room
temperature. The ingredients were reacted under conditions suitable
to hydrolyze silane groups to form corresponding silanol groups,
thereby forming a covalent inorganic/organic hybrid SiO.sub.2:
TABLE-US-00007 Resin B Ingredient Amount (g) Colloidal silica 605
(MA-ST) Silane coupling agent 18.2 (A1630) H.sub.20 4.8
[0084] Resin A and additional silane were added to the
above-described preparation of Resin B in the amounts shown below,
and the pH was adjusted to 7.5-8 with concentrated NH.sub.4OH:
TABLE-US-00008 Resin A 535.4 g Non-hydrolyzed silane (A187) 586.6
g
[0085] The resulting composition was blended by stirring in a flask
equipped with a condenser, after which volatiles were removed at
50-60 C under reduced pressure to provide the "base resin" referred
and further exemplified below. Viscosity of the final composition
was very low (approx. 17.5 cps.) when determined using a Brookfield
LVF Viscometer at 25 C.
[0086] The final product was a low viscosity (e.g., <20 cps),
clear resin, which could be stored at room temperature or frozen
until further use.
Example 2
Base Resin without Added Monomer
[0087] The Base Resin of Example 1 was mixed as follows:
TABLE-US-00009 Base resin 20.0 g Cationic photoiniator (Cyracure
6974) 1.2 g Flow control agent (BYK 307) 0.05 g
[0088] Polycarbonate lens stock was provided with a conventional
acrylic primer layer (see, e.g., Example 2, PCT/US97/07852, WO
97/45498), and the mixture was spin coated onto the primed
polycarbonate lenses and cured in one pass through a UV Cure unit
using a medium pressure mercury H bulb. Total exposure was 1.4
Joules.
[0089] The coating thickness was 4-5 microns, and had excellent
adhesion according to ASTM D3359-02 (Standard Test Methods for
Measuring Adhesion by Tape Test), using 3M 600 tape 1'' wide, when
tested both prior to and after soaking for 15 minutes in a dye bath
at 95-100 C, using black dye (available from Brain Power, Inc.
("BPI"), Miami, Fla.). The coating was also spin coated onto a
primed polycarbonate panel and tested for abrasion resistance
according to ASTM D1044-99 (Standard Test Method for Resistance of
Transparent Plastics to Surface Abrasion), modified to use the CS10
wheels resurfaced using the S-11 re-facing disks, both from Taber
Industries, 1000 cycles, 500 g. Haze value measured on a Hazegard
Meter XL 211 from BYK Gardner was determined to be <1%.
Example 3
Base Resin with Acrylic Monomers
[0090] The Base Resin from Example 1 was mixed with acrylic
monomers to form composition 3A as follows:
TABLE-US-00010 Ingredient amount (g) Base resin 20.0 Diacrylate
(HDODA) 2.8 Triacrylate (TMPTA) 2.2 Cationic photoinitiatore
(Cyracure 6974) 1.2 Free radical initiator (Irgacure 184) 0.5 Flow
control (BYK 307) 0.05
[0091] The Base Resin from Example 1 was also mixed with the
following acrylic monomers to form composition 3B as follows:
TABLE-US-00011 Ingredient amount (g) Base resin 20.0 Diacrylate
(HDODA) 1.0 Triacrylate (SR444) 4.0 Cationic photoinitiator
(Cyracure 6974) 1.2 Free radical initiator (DEAP) 0.5 Flow control
(BYK 307) 0.05
[0092] Samples of compositions 3A and 3B were spin coated onto
flat, unprimed polycarbonate panels and cured as in example 2 to
provide a film thickness of about 4.5 microns.
[0093] The abrasion resistance of cured composition 3A was
determined in the manner above, using both CS10 wheels and C17
wheels at 1000 cycles, and provided results of <1% haze and
between 6.5-8% haze, respectively. The adhesion of the composition
was determined both before and after tinting, and showed excellent
adhesion (scale 5B) in both cases. After immersion in a tint bath
as above, percent transmission was determined to be 47.5%. The
adhesion after this tint test when measured as above was
excellent.
[0094] The abrasion resistance of cured composition 3B was
determined with a CS10 wheel at 1000 cycles to provide 1-1.1% haze,
and adhesion using the above-described tape test was excellent as
well (5B), both pre- and post-tint, and transmission of 31%
following immersion in a tint bath.
[0095] Samples of composition 3B were also spun onto a high
refractive index lens (Essilor, RI 1.67), and demonstrated adhesion
of 5B as well.
[0096] It can be seen that compositions of this invention, such as
composition 3A above, can adhere very well to substrates having a
high refractive index, which is an unusual and desirable quality
for coating substrates such as optical lenses.
[0097] Examples 4, 5, 6 show the effect and usefulness of using
diluents other than acrylic monomers.
Example 4
Non-Silane Cycloaliphatic Epoxide
[0098] A composition was prepared using the following
ingredients:
TABLE-US-00012 Ingredient amount (g) Base resin 20.0 Cycloaliphatic
epoxy resin (Uvacure 1502) 5.0 Cationic photoiniatror (Cyracure
6974) 1.5 Flow control (BYK 307) 0.05
[0099] Samples were spin coated onto a flat primed polycarbonate
panel and cured as in Example 2, after which they were subjected to
the Taber Abrasion test using the CS 10 wheels, 500 cycles, 500 g.
The resulting cured coating samples provided a haze value of 1.1 to
2.0%
Example 5
Oxetane monomers
[0100] A composition was prepared using the following
ingredients:
TABLE-US-00013 Ingredient amount (g) Base resin 20.0 Oxetane
monomer (Cyracure 6000) 5.0 Cationic photoinitiator (Cyracure 6974)
1.5 Flow control (BYK 307) 0.05
[0101] Samples were spin coated on a flat polycarbonate panel and
cured as in Example 2 to provide a film thickness of about 4 to 5
microns. When tested with the Taber Abrader using the CS 10 wheels
(1000 cycles, 500 g), the haze was <1%.
Example 6
Vinyl Ether Monomers
[0102] A composition was prepared using the following
ingredients:
TABLE-US-00014 Ingredient amount (g) Base resin 20.0 Vinyl ether
monomer (Vectomer 4010) 5.0 Cationic photoinitiator (Cyracure 6974)
1.5 Flow control (BYK 307) 0.05
[0103] Samples were spin coated on a flat polycarbonate panel and
cured as in Example 2 to give a film thickness of 4-5 microns. When
tested with the Taber Abrader using CS 10 wheels (1000 cycles, 500
g), the haze was <1%.
Example 7
Effect of Varying Silica Content
[0104] The following compositions were prepared as in Example 1 in
order to vary the silica content from 5-30% in the base resin as
follows. The unhydrolysed epoxy silane was kept at a constant % in
the final resin.
TABLE-US-00015 Comp A Comp B Comp C Colloidal Silica (MA-ST) 250.0
g 250.0 g 250.0 g Silane (A1630) 16.3 g 16.3 g 16.3 g H.sub.20 4.3
g 4.3 g 4.3 g
[0105] Each mixture was stirred at room temperature for 18-20
hours, after which the following were added:
TABLE-US-00016 Comp A Comp B Comp C (5% silica) (20%) (30%) Resin A
from Example 1 211.8 g 123.7 g 53.7 g Non-hydrolyzed silane (A187)
241.8 g 165.0 g 110.0 g
[0106] The pH was adjusted to 7.5-8.0 using concentrated NH.sub.4OH
and the volatiles were removed at 50-60 C under reduced pressure.
Viscosities were between 14 centipoise and 43 centipoise were
measured on a Brookfield LVF viscometer at 25 C.
Example 8
[0107] The compositions from above Example 7 were mixed as
follows
TABLE-US-00017 Ingredient amount (g) Composition from Example 7
20.0 Diacrylate (HDODA) 2.8 Triacrylate (TMPTA) 2.2 Cationic
photoinitiator Cyracure 6974 1.2 Free radical initiator (Irgacure
184) 0.5 Flow control (BYK 307) 0.05
[0108] Samples were spin coated onto flat unprimed polycarbonate
panels and cured as in Example 2 to provide a film thickness of
about 4 to about 5 microns. When tested for abrasion resistance
using the Taber Abrader, CS 10 wheels (1000 cycles, 500 g) the haze
values were as follows. [0109] Composition A 1.3.+-.1.8% [0110]
Composition B<1% [0111] Composition C<1%
[0112] It can be seen that compositions of this invention provide
improved abrasion resistance at a wide array of colloidal silica
concentrations.
Example 9
Non-Silane Epoxy Ether Monomers
[0113] A composition was prepared having the following
ingredients:
TABLE-US-00018 Ingredients amounts (g) Base resin 20.0 Diacrylate
(HDODA) 3.0 aliphatic polyol polyepoxy (Heloxy Modifier 48) 4.0
Photoiniator (Uvacure 6974) 1.4 Acetophenone (DEAP) 0.3 Flow
control (BYK 307) 0.05
[0114] The composition was spin applied to unprimed polycarbonate
panels and cured as in Example 2 to a film thickness of 4-5
microns. As determined using the test methods above, the cured
composition demonstrated tint at 31%, abrasion resistance (1000
cycles, 500 g) of 1.2-1.6, excellent adhesion (5B). As applied to a
high refractive index lens (Essilor, RI 1.67) the cured composition
also demonstrated excellent adhesion (5B).
Example 10
Highly Tintable Compositions
[0115] Compositions were prepared having the following
ingredients:
TABLE-US-00019 Ingredients Comp A (g) Comp B (g) Base resin 20.0 --
Ex 1 Resin A (hydrolyzed silane only) -- 20.0 Diacrylate (HDODA)
3.4 3.4 Diacrylate (Sartomer SR-9209) 2.3 2.3 Vinyl ether (Vectomer
4010) 2.3 2.3 Photoinitiator (Irgacure 250) 0.57 0.57 Photoiniator
(Cyracure 6974) 0.92 0.92 Acetophenone (DEAP) 0.57 0.57 Flow
control (BYK 307) 0.06 0.06
[0116] The compositions were spin applied to unprimed polycarbonate
panels and cured as in Example 2 to a film thickness of 4-5
microns. As determined using the test methods above, the cured
compositions demonstrated tint of 12.6 and 15.2 (Compositions A and
B, respectively), abrasion resistance (1000 cycles, 500 g) of 6.7-7
and 9.9-11.1 (Compositions A and B, respectively), and excellent
adhesion (5B). As applied to a high refractive index lens (Essilor,
RI 1.67) the cured composition A also demonstrated excellent
adhesion (5B), though by contrast, composition B demonstrated only
poor to fair adhesion to such high RI substrates. The results of
this Example demonstrate the manner in which colloidal silica plays
an important role in improving properties, including for use on
high RI lenses.
Example 11
Effect of Varying Silica Content
[0117] The following compositions were prepared as in Example 1 in
order to vary the colloidal silica content in the absence of an
organofunctional polysiloxane.
[0118] Silane treated colloidal silica (Resin B as above) was
prepared as follows, by mixing colloidal silica and silane in a
flask fitted with a condenser for 18-20 hrs at room temperature.
The ingredients were reacted under conditions suitable to hydrolyze
silane groups to form corresponding silanol groups, thereby forming
a covalent inorganic/organic hybrid SiO
TABLE-US-00020 Ingredient Amount (g) Resin B Colloidal silica 985.3
(MA-ST) Silane coupling agent 64.2 (A1630) H.sub.20 16.9
[0119] A silane coupling agent (638.8 g, A187) was added to Resin
B, the pH of the composition adjusted to 7.5 to 8 with NH4OH, and
was stripped of volatiles to yield 992 grams of a Base product
having 29.8% silica by weight and a viscosity of 17 centipoise as
determined on a Brookfield LVF viscometer at 25 C. Comparative
compositions were prepared to yield differing silica concentrations
using the following ingredients and amounts.
TABLE-US-00021 Comp A Comp B Comp C (28.42% silica) (4.67%) (1.95%)
Base 10 2 0.7 Cationic photoinitiator 0.42 0.68 9.3 (Cyracure 6974)
Flow control agent (BYK 307) 0.03 0.03 0.03
[0120] The compositions were spin applied to unprimed polycarbonate
panels and cured as in Example 2 to a film thickness of 4-5
microns. As determined using the test methods above, the cured
compositions demonstrated abrasion resistance (500 cycles, 500 g,
CS10 wheels) as follows:
TABLE-US-00022 Delta haze Composition A 0.5-0.8%, Composition B
1.9-2.3% Composition C 2.5-3.0%
[0121] The results of this Example demonstrate the manner in which
increased colloidal silica concentration tends to correspond with
improved abrasion resistance.
* * * * *