U.S. patent application number 09/031932 was filed with the patent office on 2001-12-06 for composition for providing an abrasion resistant coating on a substrate.
Invention is credited to GUEST, ALLEN M., HAVEY, JANET L., HO, TUAN H., SOLLBERGER, MARK S., TERRY, KARL W..
Application Number | 20010049023 09/031932 |
Document ID | / |
Family ID | 25283338 |
Filed Date | 2001-12-06 |
United States Patent
Application |
20010049023 |
Kind Code |
A1 |
HAVEY, JANET L. ; et
al. |
December 6, 2001 |
COMPOSITION FOR PROVIDING AN ABRASION RESISTANT COATING ON A
SUBSTRATE
Abstract
Compositions having improved stability which, when applied to a
variety of substrates and cured, form transparent coatings having
superior abrasion resistant properties. The coating compositions
are aqueous-organic solvent mixtures containing a mixture of
hydrolysis products and partial condensates of an epoxy functional
silane and tetrafunctional silane and a multifunctional compound
selected from the group consisting of multifunctional carboxylic
acids, multifunctional anhydrides and combinations thereof.
Inventors: |
HAVEY, JANET L.; (LA MIRADA,
CA) ; HO, TUAN H.; (RANCHO SANTA MARGARITA, CA)
; GUEST, ALLEN M.; (CHINO, CA) ; TERRY, KARL
W.; (HUNTINGTON BEACH, CA) ; SOLLBERGER, MARK S.;
(IRVINE, CA) |
Correspondence
Address: |
GLEN M BURDICK
DUNLAP & CODDING
SUITE 420
9400 NORTH BROADWAY
OKLAHOMA CITY
OK
73114
|
Family ID: |
25283338 |
Appl. No.: |
09/031932 |
Filed: |
February 27, 1998 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09031932 |
Feb 27, 1998 |
|
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08840831 |
Apr 17, 1997 |
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6001163 |
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Current U.S.
Class: |
428/429 ;
428/331; 428/451; 428/452 |
Current CPC
Class: |
C09D 4/00 20130101; C08K
5/5435 20130101; Y10T 428/31667 20150401; Y10T 428/31663 20150401;
Y10T 428/31612 20150401; C08G 59/3254 20130101; Y10T 428/259
20150115; Y10T 428/662 20150401; Y10T 428/4935 20150401; C08K 5/092
20130101; C08K 5/092 20130101; C08L 83/04 20130101; C08K 5/5435
20130101; C08L 83/04 20130101; C09D 4/00 20130101; C08G 77/04
20130101 |
Class at
Publication: |
428/429 ;
428/451; 428/452; 428/331 |
International
Class: |
B32B 017/06 |
Claims
What is claimed:
1. A composition having improved stability and which, when applied
to a substrate and cured, provides an abrasion resistant coating on
the substrate, comprising: an aqueous-organic solvent mixture
containing hydrolysis products and partial condensates of an epoxy
functional silane, a tetrafunctional silane and a multifunctional
compound wherein the multifunctional compound is selected from the
group consisting of multifunctional carboxylic acids,
multifunctional anhydrides and combinations thereof and wherein the
epoxy functional silane is present in a molar ratio to the
tetrafunctional silane of from about 0.1:1 to about 5:1.
2. The composition of claim 1 wherein the hydrolysis products and
partial condensates of the epoxy functional silane and the
tetrafunctional silane are present in the aqueous-organic solvent
mixture in an amount of from about 10 to about 99.9 weight percent,
based on the total solids of the coating composition and wherein
the multifunctional compound is present in the aqueous-organic
solvent mixture in an amount of from about 0.1 to about 30 weight
percent, based on the total solids of the coating composition.
3. The composition of claim 1 wherein the solvent constituent of
the aqueous-organic solvent mixture is selected from the group
consisting of an alcohol, an ether, a glycol, a glycol ether, an
ester, a ketone, a glycolether acetate and mixtures thereof.
4. The composition of claim 1 wherein the solvent constituent of
the aqueous-organic solvent mixture is an alcohol having the
general formula ROH where R is an alkyl group containing from 1 to
about 10 carbon atoms.
5. The composition of claim 1 wherein the solvent constituent of
the aqueous-organic solvent mixture is selected from the group
consisting of a glycol, an ether, a glycol ether and mixtures
thereof having the formula R.sup.1--(OR.sup.2).sub.x--OR.sup.1
where x is an integer of 0, 1, 2, 3 or 4, R.sup.1 is H or an alkyl
group containing from 1 to about 10 carbon atoms and R.sup.2 is an
alkylene group containing from 1 to about 10 carbon atoms and
combinations thereof.
6. The composition of claim 1 wherein the epoxy functional silane
is present in a molar ratio to the tetrafunctional silane of from
about 0.1:1 to about 3:1.
7. The composition of claim 1 wherein the epoxy functional silane
is represented by the formula R.sup.3.sub.xSi(OR.sup.4).sub.4-x
where x is an integer of 1, 2 or 3, R.sup.3 is H, an alkyl group, a
functionalized alkyl group, an alkylene group, an aryl group, an
alkyl ether, and combinations thereof containing from 1 to about 10
carbon atoms and having at least 1 epoxy functional group, and
R.sup.4 is H, an alkyl group containing from 1 to about 5 carbon
atoms, an acetyl group, a --Si(OR.sup.5).sub.3-y R.sup.6.sub.y
group where y is an integer of 0, 1, 2, or 3, and combinations
thereof where R.sup.5 is H, an alkyl group containing from 1 to
about 5 carbon atoms an acetyl group, another
--Si(OR.sup.5).sub.3-yR.sup.6.sub.y group and combinations thereof,
and R.sup.6 is H, an alkyl group, a functionalized alkyl group, an
alkylene group, an aryl group, an alkyl ether and combinations
thereof containing from 1 to about 10 carbon atoms.
8. The composition of claim 7 wherein the tetrafunctional silane is
represented by the formula Si(OR.sup.7).sub.4 where R.sup.7 is H,
an alkyl group containing from 1 to about 5 carbon atoms and ethers
thereof, an (OR.sup.7) carboxylate, a --Si(OR.sup.8).sub.3 group
where R.sup.8 is a H, an alkyl group containing from 1 to about 5
carbon atoms and ethers thereof, an (OR.sup.8) carboxylate, another
--Si(OR.sup.8).sub.3 group and combinations thereof.
9. The composition of claim 1 wherein the hydrolysis products and
partial condensates of the epoxy functional silane and the
tetrafunctional silane are present in the aqueous-organic solvent
mixture in an amount of from about 10 to about 99.9 weight percent,
based on the total solids of the coating composition and wherein
the multifunctional compound is present in the aqueous-organic
solvent mixture in an amount of from about 0.1 to about 30 weight
percent, based on the total solids of the coating composition and
wherein the epoxy functional silane is represented by the formula
R.sup.3.sub.xSi(OR.sup.4).sub.4-x where x is an integer of 1, 2 or
3, R.sup.3 is H, an alkyl group, a functionalized alkyl group, an
alkylene group, an aryl group, an alkyl ether, and combinations
thereof containing from 1 to about 10 carbon atoms and having at
least 1 epoxy functional group, and R.sup.4 is H, an alkyl group
containing from 1 to about 5 carbon atoms, an acetyl group, a
--Si(OR.sup.5).sub.3-yR.sup.6.su- b.y group where y is an integer
of 0, 1, 2, or 3, and combinations thereof where R.sup.5 is H, an
alkyl group containing from 1 to about 5 carbon atoms, an acetyl
group, or another --Si(OR.sup.5).sub.3-yR.sup.6.sub.y group and
combinations thereof, and R.sup.6 is H, an alkyl group, a
functionalized alkyl group, an alkylene group, an aryl group, an
alkyl ether, and combinations thereof containing from 1 to about 10
carbon atoms.
10. The composition of claim 9 wherein the tetrafunctional silane
is represented by the formula Si(OR.sup.7).sub.4 where R.sup.7 is
H, an alkyl group containing from 1 to about 5 carbon atoms and
ethers thereof, an (OR.sup.7) carboxylate, a --Si(OR.sup.8).sub.3
group where R.sup.8 is a H, an alkyl group containing from 1 to
about 5 carbon atoms and ethers thereof, an (OR.sup.8) carboxylate,
another --(OR.sup.8).sub.3 group and combinations thereof.
11. The composition of claim 10 wherein the solvent constituent of
the aqueous-organic solvent mixture is an alcohol having the
general formula ROH where R is an alkyl group containing from 1 to
about 10 carbon atoms.
12. The composition of claim 10 wherein the solvent constituent of
the aqueous-organic solvent mixture is selected from the group
consisting of a glycol, an ether, a glycol ether and mixtures
thereof having the formula R.sup.1--(OR.sup.2).sub.x--OR.sup.1
where x is an integer of 0, 1, 2, 3 or 4, R.sup.1 is H or an alkyl
group containing from 1 to about 10 carbon atoms and R.sup.2 is an
alkylene group containing from 1 to about 10 carbon atoms and
combinations thereof.
13. The composition of claim 10 wherein the amount of water present
in the aqueous-organic solvent dispersion is an amount sufficient
to provide a substantially homogeneous mixture of hydrolysis
products and partial condensates of the epoxy functional silane and
the tetrafunctional silane.
14. The composition of claim 1 wherein the tetrafunctional silane
is represented by the formula Si(OR.sup.7).sub.4 where R.sup.7 is
H, an alkyl group containing from 1 to about 5 carbon atoms and
ethers thereof, an (OR.sup.7) carboxylate, a --Si(OR.sup.8).sub.3
group where R.sup.8 is a H, an alkyl group containing from 1 to
about 5 carbon atoms and ethers thereof, an (OR.sup.8) carboxylate,
another --Si(OR.sup.8).sub.3 group and combinations thereof.
15. The composition of claim 1 wherein at least a portion of the
solvent component of the aqueous-organic solvent mixture is
generated during hydrolysis of the epoxy functional silane and the
tetrafunctional silane.
16. The composition of claim 1 further comprising an effective
amount of a catalyst to provide enhanced abrasion resistance to a
coating produced by curing the composition.
17. The composition of claim 16 wherein the effective amount of the
catalyst is from about 0.1 to about 10 weight percent, based on the
total solids of the composition.
18. The composition of claim 17 wherein the aqueous-organic solvent
mixture further comprises from about 0.1 to about 50 weight
percent, based on the total solids of the composition, of a mixture
of hydrolysis products and partial condensates of an alkyl silane
represented by the formula R.sup.9.sub.xSi(OR.sup.10).sub.4-x where
x is an integer of 1, 2 or 3, R.sup.9 is H, an alkyl group
containing from 1 to about 10 carbon atoms, a functionalized alkyl
group, an alkylene group, an aryl group, an alkoxypolyether 10
group and combinations thereof, R.sup.10 is H, an alkyl group
containing from 1 to about 10 carbon atoms, an acetyl group and
combinations thereof.
19. The composition of claim 18 wherein the aqueous-organic solvent
mixture further comprises: an effective amount of a leveling agent
to spread the aqueous-organic solvent mixture on the substrate and
provide substantially uniform contact of the aqueous-organic
solvent mixture with the substrate.
20. The composition of claim 1 wherein the aqueous-organic solvent
mixture further comprises from about 0.1 to about 50 weight
percent, based on the total solids of the composition, of a mixture
of hydrolysis products and partial condensates of an alkyl silane
represented by the formula R.sup.9.sub.xSi(OR.sup.10).sub.4-x where
x is an integer of 1, 2 or 3, R.sup.9 is H, an alkyl group
containing from 1 to about 10 carbon atoms, a functionalized alkyl
group, an alkylene group, an aryl group an alkoxypolyether group
and combinations thereof, R.sup.10 is H, an alkyl group containing
from 1 to about 10 carbon atoms, an acetyl group and combinations
thereof.
21. The composition of claim 20 wherein the aqueous-organic solvent
mixture further comprises: an effective amount of a leveling agent
to spread the aqueous-organic solvent mixture on the substrate and
provide substantially uniform contact of the aqueous-organic
solvent mixture with the substrate.
22. The composition of claim 1 wherein the aqueous-organic solvent
mixture further comprises: from about 0.1 to about 50 weight
percent, based on the total solids of the composition, of a mixture
of hydrolysis products and partial condensates of an alkyl silane
represented by the formula R.sup.9.sub.xSi(OR.sup.10).sub.4-x where
x is an integer of 1, 2 or 3, R.sup.9 is H, an alkyl group
containing from 1 to about 10 carbon atoms, a functionalized alkyl
group, an alkylene group, an aryl group an alkoxypolyether group
and combinations thereof, R.sup.10 is H, an alkyl group containing
from 1 to about 10 carbon atoms, an acetyl group and combinations
thereof; and an effective amount of colloidal silica to provide the
composition with from about 0.1 to about 50 weight percent silica,
based on the total of solids present in the composition.
23. The composition of claim 22 further comprising an effective
amount of a catalyst to provide enhanced abrasion resistance to a
coating produced by curing the composition.
24. The composition of claim 23 wherein the effective amount of the
catalyst is from about 0.1 to about 10 weight percent, based on the
total solids of the composition.
25. The composition of claim 23 wherein the aqueous-organic solvent
mixture further comprises: an effective amount of a leveling agent
to spread the aqueous-organic solvent mixture on the substrate and
provide substantially uniform contact of the aqueous-organic
solvent mixture with the substrate.
26. The composition of claim 1 wherein the aqueous-organic solvent
mixture further comprises: an effective amount of colloidal silica
to provide the composition with from about 0.1 to about 50 weight
percent silica, based on the total of solids present in the
composition.
27. The composition of claim 26 wherein the aqueous-organic solvent
mixture further comprises: an effective amount of a leveling agent
to spread the aqueous-organic solvent mixture on the substrate and
provide substantially uniform contact of the aqueous-organic
solvent mixture with the substrate.
28. The composition of claim 27 wherein the amount of water present
in the aqueous-organic solvent mixture is an amount at least
sufficient to hydrolyze the epoxy functional silane and the
tetrafunctional silane.
29. The composition of claim 28 wherein the aqueous-organic solvent
mixture further comprises an effective amount of a catalyst to
provide enhanced abrasion resistance to the coating produced by
curing the aqueous solvent mixture.
30. The composition of claim 29 wherein the effective amount of a
catalyst present in the aqueous-organic solvent mixture is from
about 0.1 to about 10 weight percent, based on the total solids of
the of the aqueous-organic solvent mixture.
31. The composition of claim 29 wherein the aqueous-organic solvent
mixture further comprises from about 0.1 to about 50 weight
percent, based on the total of solids of the aqueous-organic
solvent mixture, of a mixture of hydrolysis products and partial
condensates of an alkyl silane represented by the formula
R.sup.9.sub.xSi(OR.sup.10).sub.4-x where x is an integer of 1, 2 or
3, R.sup.9 is H, an alkyl group containing from 1 to about 10
carbon atoms, a functionalized alkyl group, an alkylene group, an
aryl group, an alkoxypolyether group and combinations thereof,
R.sup.10 is H, an alkyl group containing from 1 to about 10 carbon
atoms, an acetyl group and combinations thereof.
32. The composition of claim 1 wherein the aqueous-organic solvent
mixture further comprises: an effective amount of a leveling agent
to spread the aqueous-organic solvent mixture on the substrate and
provide substantially uniform contact of the aqueous-organic
solvent mixture with the substrate.
33. An article comprising: a substrate; and a substantially
transparent abrasion-resistant coating formed on at least one
surface of the substrate wherein the coating is formed by curing a
coating composition comprising an aqueous-organic solvent mixture
applied to the surface of the substrate and wherein the
aqueous-organic solvent mixture contains: from about 10 to about
99.9 weight percent, based on the total solids of the composition,
of hydrolysis products and partial condensates of an epoxy
functional silane and a tetrafunctional silane wherein the epoxy
functional silane is present in a molar ratio to the
tetrafunctional silane of from about 0.1:1 to about 5:1 and the
solvent component of the aqueous solvent dispersion is compatible
with the epoxy functional silane and the tetrafunctional silane;
and from about 0.1 to about 30 weight percent of a multifunctional
compound, based on the total solids of the composition, wherein the
multifunctional compound is selected from the group consisting of
multifunctional carboxylic acids, multifunctional anhydrides and
mixtures thereof.
34. The article of claim 33 wherein the epoxy functional silane is
present in a molar ratio to the tetrafunctional silane of from
about 0.1:1 to about 3:1.
35. The article of claim 33 wherein the solvent constituent of the
aqueous-organic solvent mixture is selected from the group
consisting of an alcohol, an ether, a glycol, a glycol ether, an
ester, a ketone, a glycolether acetate and mixtures thereof.
36. The article of claim 33 wherein the solvent constituent of the
aqueous-organic solvent mixture is an alcohol having the general
formula ROH where R is an alkyl group containing from 1 to about 10
carbon atoms.
37. The article of claim 33 wherein the solvent constituent of the
aqueous-organic solvent mixture is selected from the group
consisting of a glycol, an ether, a glycol ether and mixtures
thereof having the formula R.sup.1--(OR.sup.2).sub.x--OR.sup.1
where x is an integer of 0, 1, 2, 3 or 4, R.sup.1 is H or an alkyl
group containing from 1 to about 10 carbon atoms and R.sup.2 is an
alkylene group containing from 1 to about 10 carbon atoms and
combinations thereof.
38. The article of claim 33 wherein the epoxy functional silane is
represented by the formula R.sup.3.sub.xSi(OR.sup.4).sub.4-x where
x is an integer of 1, 2 or 3, R.sup.3 is H, an alkyl group, a
functionalized alkyl group, an alkylene group, an aryl group, an
alkyl ether and combinations thereof containing from 1 to about 10
carbon atoms and having at least 1 epoxy functional group, and
R.sup.4 is H, an alkyl group containing from 1 to about 5 carbon
atoms, an acetyl group, a --Si(OR.sup.5).sub.3-yR.sup.6.sub.y group
where y is an integer of 0, 1, 2, or 3, and combinations thereof
where R.sup.5 is H, an alkyl group containing from 1 to about 5
carbon atoms, an acetyl group, another
--Si(OR.sup.5).sub.3-yR.sup.6.sub.y group and combinations thereof,
and R.sup.6 is H, an alkyl group, a functionalized alkyl group, an
alkylene group, an aryl group, an alkyl ether and combinations
thereof containing from 1 to about 10 carbon atoms.
39. The article of claim 38 wherein the tetrafunctional silane is
represented by the formula Si(OR.sup.7).sub.4 where R.sup.7 is H,
an alkyl group containing from 1 to about 5 carbon atoms and ethers
thereof, an (OR.sup.7) carboxylate, a --Si(OR.sup.8).sub.3 group
where R.sup.8 is a H, an alkyl group containing from 1 to about 5
carbon atoms and ethers thereof, an (OR.sup.8) carboxylate, another
--Si(OR.sup.8).sub.3 group and combinations thereof.
40. The article of claim 39 wherein the solvent constituent of the
aqueous-organic solvent mixture is an alcohol having the general
formula ROH where R is an alkyl group containing from 1 to about 10
carbon atoms.
41. The article of claim 39 wherein the solvent constituent of the
aqueous-organic solvent mixture is selected from the group
consisting of a glycol, an ether, a glycol ether and mixtures
thereof having the formula R.sup.1--(OR.sup.2).sub.x--OR.sup.1
where x is an integer of 0, 1, 2, 3 or 4, R.sup.1 is H or an alkyl
group containing from 1 to about 10 carbon atoms and R.sup.2 is an
alkylene group containing from 1 to about 10 carbon atoms and
combinations thereof.
42. The article of claim 39 wherein the amount of water present in
the aqueous-organic solvent dispersion is an amount sufficient to
provide a substantially homogeneous mixture of hydrolysis products
and partial condensates of the epoxy functional silane and the
tetrafunctional silane.
43. The article of claim 33 wherein the tetrafunctional silane is
represented by the formula Si(OR.sup.7).sub.4 where R.sup.7 is H,
an alkyl group containing from 1 to about 5 carbon atoms and ethers
thereof, an (OR.sup.7) carboxylate, a --Si(OR.sup.8).sub.3 group
where R.sup.8 is a H, an alkyl group containing from 1 to about 5
carbon atoms and ethers thereof, an (OR.sup.8) carboxylate, another
--Si(OR.sup.8).sub.3 group and combinations thereof.
44. The article of claim 33 wherein at least a portion of the
solvent component of the aqueous-organic solvent mixture is
generated during hydrolysis of the epoxy functional silane and the
tetrafunctional silane.
45. The article of claim 35 wherein the aqueous-organic solvent
mixture further comprises an effective amount of a catalyst to
provide enhanced abrasion resistance to a coating produced by
curing the composition.
46. The article of claim 45 wherein the effective amount of the
catalyst is from about 0.1 to about 10 weight percent, based on the
total solids of the composition.
47. The article of claim 46 wherein the aqueous-organic solvent
mixture further comprises from about 0.1 to about 50 weight
percent, based on the total solids of the composition, of a mixture
of hydrolysis products and partial condensates of an alkyl silane
represented by the formula R.sup.9.sub.xSi(OR.sup.10).sub.4-x where
x is an integer of 1, 2 or 3, R.sup.9 is H, an alkyl group
containing from 1 to about 10 carbon atoms, a functionalized alkyl
group, an alkylene group, an aryl group, an alkoxypolyether group
and combinations thereof, R.sup.10 is H, an alkyl group containing
from 1 to about 10 carbon atoms, an acetyl group and combinations
thereof.
48. The article of claim 47 wherein the aqueous-organic solvent
mixture further comprises: an effective amount of a leveling agent
to spread the aqueous-organic solvent mixture on the substrate and
provide substantially uniform contact of the aqueous-organic
solvent mixture with the substrate.
49. The article of claim 33 wherein the aqueous-organic solvent
mixture further comprises from about 0.1 to about 50 weight
percent, based on the total solids of the composition, of a mixture
of hydrolysis products and partial condensates of an alkyl silane
represented by the formula R.sup.9.sub.xSi(OR.sup.10).sub.4-x where
x is an integer of 1, 2 or 3, R.sup.9 is H, an alkyl group
containing from 1 to about 10 carbon atoms, a functionalized alkyl
group, an alkylene group, an aryl group, an alkoxypolyether group
and combinations thereof, R.sup.10 is H, an alkyl group containing
from 1 to about 10 carbon atoms, an acetyl group and combinations
thereof.
50. The article of claim 49 wherein the aqueous-organic solvent
mixture further comprises: an effective amount of a leveling agent
to spread the aqueous-organic solvent mixture on the substrate and
provide substantially uniform contact of the aqueous-organic
solvent mixture with the substrate.
51. The article of claim 33 wherein the aqueous-organic solvent
mixture further comprises: from about 0.1 to about 50 weight
percent, based on the total solids of the composition, of a mixture
of hydrolysis products and partial condensates of an alkyl silane
represented by the formula R.sup.9.sub.xSi(OR.sup.10).sub.4-x where
x is an integer of 1, 2 or 3, R.sup.9 is H, an alkyl group
containing from 1 to about 10 carbon atoms, a functionalized alkyl
group, an alkylene group, an aryl group, an alkoxypolyether group
and combinations thereof, R.sup.10 is H, an alkyl group containing
from 1 to about 10 carbon atoms, an acetyl group and combinations
thereof; and an effective amount of colloidal silica to provide the
composition with from about 0.1 to about 50 weight percent silica,
based on the total of solids present in the composition.
52. The article of claim 51 wherein the aqueous-organic solvent
mixture further comprises an effective amount of a catalyst to
provide enhanced abrasion resistance to a coating produced by
curing the composition.
53. The article of claim 52 wherein the effective amount of the
catalyst is from about 0.1 to about 10 weight percent, based on the
total solids of the composition.
54. The article of claim 53 wherein the aqueous-organic solvent
mixture further comprises: an effective amount of a leveling agent
to spread the aqueous-organic solvent mixture on the substrate and
provide substantially uniform contact of the aqueous-organic
solvent mixture with the substrate.
55. The article of claim 33 wherein the aqueous-organic solvent
mixture further comprises: an effective amount of colloidal silica
to provide the composition with from about 0.1 to about 50 weight
percent silica, based on the total of solids present in the
composition.
56. The article of claim 55 wherein the aqueous-organic solvent
mixture further comprises: an effective amount of a leveling agent
to spread the aqueous-organic solvent mixture on the substrate and
provide substantially uniform contact of the aqueous-organic
solvent mixture with the substrate.
57. The article of claim 56 wherein the amount of water present in
the aqueous-organic solvent mixture is an amount sufficient to
provide a substantially homogeneous mixture of hydrolysis products
and partial condensates of the epoxy functional silane and the
tetrafunctional silane.
58. The article of claim 57 wherein the aqueous-organic solvent
mixture further comprises an effective amount of a catalyst to
provide enhanced abrasion resistance to the coating produced by
curing the aqueous solvent mixture.
59. The article of claim 58 wherein the effective amount of a
catalyst present in the aqueous-organic solvent mixture is from
about 0.1 to about 10 weight percent, based on the total solids of
the of the aqueous-organic solvent mixture.
60. The article of claim 58 wherein the aqueous-organic solvent
mixture further comprises from about 0.1 to about 50 weight
percent, based on the total of solids of the aqueous-organic
solvent mixture, of a mixture of hydrolysis products and partial
condensates of an alkyl silane represented by the formula
R.sup.9.sub.xSi(OR.sup.10).sub.4-x where x is an integer of 1, 2 or
3, R.sup.9 is H, an alkyl group containing from 1 to about 10
carbon atoms, a functionalized alkyl group, an alkylene group, an
aryl group, an alkoxypolyether group and combinations thereof,
R.sup.10 is H, an alkyl group containing from 1 to about 10 carbon
atoms, an acetyl group and combinations thereof.
61. The article of claim 33 wherein the aqueous-organic solvent
mixture further comprises: an effective amount of a leveling agent
to spread the aqueous-organic solvent mixture on the substrate and
provide substantially uniform contact of the aqueous-organic
solvent mixture with the substrate.
62. The article of claim 33 wherein the substrate is formed of
plastic, wood, ceramic, glass ceramic, glass, mineral based,
leather, paper, textile and metal materials.
63. A process for providing a substantially transparent, abrasion
resistant coating on a substrate, comprising: applying to at least
one surface of a substrate an effective amount of an
aqueous-organic solvent mixture to provide a substantially uniform
coating on the substrate, the aqueous-organic solvent mixture
comprising hydrolysis products and partial condensates of an epoxy
functional silane, a tetrafunctional silane and a multifunctional
compound wherein the multifunctional compound is selected from the
group consisting of multifunctional carboxylic acids,
multifunctional anhydrides and combinations thereof and wherein the
epoxy functional silane is present in a molar ratio to the
tetrafunctional silane of from about 0.1:1 to about 5:1; and curing
the coating composition to produce a substantially transparent,
abrasion resistant coating on the substrate.
64. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 63 wherein the hydrolysis
products and partial condensates of the epoxy functional silane and
the tetrafunctional silane are present in the aqueous-organic
solvent mixture in an amount of from about 10 to about 99.9 weight
percent, based on the total solids of the coating composition and
wherein the multifunctional compound is present in the
aqueous-organic solvent mixture in an amount of from about 0.1 to
about 30 weight percent, based on the total solids of the coating
composition.
65. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 63 wherein the solvent
constituent of the aqueous-organic solvent mixture is an alcohol
having the general formula ROH where R is an alkyl group containing
from 1 to about 10 carbon atoms.
66. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 63 wherein the solvent
constituent of the aqueous-organic solvent mixture is selected from
the group consisting of a glycol, an ether, a glycol ether and
mixtures thereof having the formula
R.sup.1--(OR.sup.2).sub.x--OR.sup.1 where x is an integer of 0, 1,
2, 3 or 4, R.sup.1 is H or an alkyl group containing from 1 to
about 10 carbon atoms and R.sup.2 is an alkylene group containing
from 1 to about 10 carbon atoms and combinations thereof.
67. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 63 wherein the epoxy
functional silane is present in the aqueous-organic solvent mixture
in a molar ratio to the tetrafunctional silane of from about 0.1:1
to about 3:1.
68. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 63 wherein the epoxy
functional silane present in the aqueous-organic mixture is
represented by the formula R.sup.3.sub.xSi(OR.sup.4).sub.4-x where
x is an integer of 1, 2 or 3, R.sup.3 is H, an alkyl group, a
functionalized alkyl group, an alkylene group, an aryl group, an
alkyl ether and combinations thereof containing from 1 to about 10
carbon atoms and having at least 1 epoxy functional group, and
R.sup.4 is H. an alkyl group containing from 1 to about 5 carbon
atoms, an acetyl group, a --Si(OR.sup.5).sub.3-yR.sup.6.su- b.y
group where y is an integer of 0, 1, 2, or 3, and combinations
thereof where R.sup.5 is H, an alkyl group containing from 1 to
about 5 carbon atoms an acetyl group, another
--Si(OR.sup.5).sub.3-yR.sup.6.sub.y group and combinations thereof,
and R.sup.6 is H, an alkyl group, a functionalized alkyl group, an
alkylene group, an aryl group, an alkyl ether and combinations
thereof containing from 1 to about 10 carbon atoms.
69. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 68 wherein the
tetrafunctional silane present in the aqueous-organic mixture is
represented by the formula Si(OR.sup.7).sub.4 where R.sup.7 is H,
an alkyl group containing from 1 to about 5 carbon atoms and ethers
thereof, an (OR.sup.7) carboxylate, a --Si(OR.sup.8).sub.3 group
where R.sup.8 is a H, an alkyl group containing from 1 to about 5
carbon atoms and ethers thereof, an (OR.sup.8) carboxylate, another
--Si(OR.sup.8).sub.3 group and combinations thereof.
70. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 63 wherein the hydrolysis
products and partial condensates of the epoxy functional silane and
the tetrafunctional silane are present in the aqueous-organic
solvent mixture in an amount of from about 10 to about 99.9 weight
percent, based on the total solids of the coating composition and
wherein the multifunctional compound is present in the
aqueous-organic solvent mixture in an amount of from about 0.1 to
about 30 weight percent, based on the total solids of the coating
composition and wherein the epoxy functional silane is represented
by the formula R.sup.3.sub.xSi(OR.sup.4).sub.4-x where x is an
integer of 1, 2 or 3, R.sup.3 is H, an alkyl group, a
functionalized alkyl group, an alkylene group, an aryl group, an
alkyl ether and combinations thereof containing from 1 to about 10
carbon atoms and having at least 1 epoxy functional group, and
R.sup.4 is H, an alkyl group containing from 1 to about 5 carbon
atoms, an acetyl group, a --Si(OR.sup.5).sub.3-yR.sup.6.sub.y group
where y is an integer of 0, 1, 2, or 3, and combinations thereof
where R.sup.5 is H, an alkyl group containing from 1 to about 5
carbon atoms, an acetyl group, another
--Si(OR.sup.5).sub.3-yR.sup.6.sub.y group and combinations thereof,
and R.sup.6 is H. an alkyl group, a functionalized alkyl group, an
alkylene group, an aryl group, an alkyl ether and combinations
thereof containing from 1 to about 10 carbon atoms.
71. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 70 wherein the
tetrafunctional silane present in the aqueous-organic mixture is
represented by the formula Si(OR.sup.7).sub.4 where R.sup.7 is H,
an alkyl group containing from 1 to about 5 carbon atoms and ethers
thereof, an (OR.sup.7) carboxylate, a --Si(OR.sup.8).sub.3 group
where R.sup.8 is a H, an alkyl group containing from 1 to about 5
carbon atoms and ethers thereof, an (OR.sup.8) carboxylate, another
--Si(OR.sup.8).sub.3 group and combinations thereof.
72. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 71 wherein the solvent
constituent of the aqueous-organic solvent mixture is an alcohol
having the general formula ROH where R is an alkyl group containing
from 1 to about 10 carbon atoms.
73. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 71 wherein the solvent
constituent of the aqueous-organic solvent mixture is selected from
the group consisting of a glycol, an ether, a glycol ether and
mixtures thereof having the formula
R.sup.1--(OR.sup.2).sub.x--OR.sup.1 where x is an integer of 0, 1,
2, 3 or 4, R.sup.1 is H or an alkyl group containing from 1 to
about 10 carbon atoms and R.sup.2 is an alkylene group containing
from 1 to about 10 carbon atoms and combinations thereof.
74. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 71 wherein the amount of
water present in the aqueous-organic solvent dispersion is an
amount sufficient to provide a substantially homogeneous mixture of
hydrolysis products and partial condensates of the epoxy functional
silane and the tetrafunctional silane.
75. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 63 wherein the
tetrafunctional silane present in the aqueous-organic solvent
mixture is represented by the formula Si(OR.sup.7).sub.4 where
R.sup.7 is H, an alkyl group containing from 1 to about 5 carbon
atoms and ethers thereof, an (OR.sup.7) carboxylate, a
--Si(OR.sup.8).sub.3 group where R.sup.8 is a H, an alkyl group
containing from 1 to about 5 carbon atoms and ethers thereof, an
(OR.sup.8) carboxylate, another --Si(OR.sup.8).sub.3 group and
combinations thereof.
76. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 63 wherein at least a
portion of the solvent component of the aqueous-organic solvent
mixture is generated during hydrolysis of the epoxy functional
silane and the tetrafunctional silane.
77. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 63 wherein the
aqueous-organic solvent mixture further comprises an effective
amount of a catalyst to provide enhanced abrasion resistance to a
coating produced by curing the composition.
78. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 77 wherein the effective
amount of the catalyst is from about 0.1 to about 10 weight
percent, based on the total solids of the composition.
79. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 78 wherein the
aqueous-organic solvent mixture further comprises from about 0.1 to
about 50 weight percent, based on the total solids of the
composition, of a mixture of hydrolysis products and partial
condensates of an alkyl silane represented by the formula
R.sup.9.sub.xSi(OR.sup.10).sub.4-x where x is an integer of 1, 2 or
3, R.sup.9 is H, an alkyl group containing from 1 to about 10
carbon atoms, a functionalized alkyl group, an alkylene group, an
aryl group, an alkoxypolyether group and combinations thereof,
R.sup.10 is H, an alkyl group containing from 1 to about 10 carbon
atoms, an acetyl group and combinations thereof.
80. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 79 wherein the
aqueous-organic solvent mixture further comprises: an effective
amount of a leveling agent to spread the aqueous-organic solvent
mixture on the substrate and provide substantially uniform contact
of the aqueous-organic solvent mixture with the substrate.
81. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 63 wherein the
aqueous-organic solvent mixture further comprises from about 0.1 to
about 50 weight percent, based on the total solids of the
composition, of a mixture of hydrolysis products and partial
condensates of an alkyl silane represented by the formula
R.sup.9.sub.xSi(OR.sup.10).sub.4-x where x is an integer of 1, 2 or
3, R.sup.9 is H, an alkyl group containing from 1 to about 10
carbon atoms, a functionalized alkyl group, an alkylene group, an
aryl group, an alkoxypolyether group and combinations thereof,
R.sup.10 is H, an alkyl group containing from 1 to about 10 carbon
atoms, an acetyl group and combinations thereof.
82. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 81 wherein the
aqueous-organic solvent mixture further comprises: an effective
amount of a leveling agent to spread the aqueous-organic solvent
mixture on the substrate and provide substantially uniform contact
of the aqueous-organic solvent mixture with the substrate.
83. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 63 wherein the
aqueous-organic solvent mixture further comprises: from about 0.1
to about 50 weight percent, based on the total solids of the
composition, of a mixture of hydrolysis products and partial
condensates of an alkyl silane represented by the formula
R.sup.9.sub.xSi(OR.sup.10).sub.4-x where x is an integer of 1, 2 or
3, R.sup.9 is H, an alkyl group containing from 1 to about 10
carbon atoms, a functionalized alkyl group, an alkylene group, an
aryl group, an alkoxypolyether group and combinations thereof,
R.sup.10 is H, an alkyl group containing from 1 to about 10 carbon
atoms, an acetyl group and combinations thereof; and an effective
amount of colloidal silica to provide the composition with from
about 0.1 to about 50 weight percent silica, based on the total of
solids present in the composition.
84. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 83 wherein the
aqueous-organic solvent mixture further comprises an effective
amount of a catalyst to provide enhanced abrasion resistance to a
coating produced by curing the composition.
85. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 84 wherein the effective
amount of the catalyst is from about 0.1 to about 10 weight
percent, based on the total solids of the composition.
86. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 84 wherein the
aqueous-organic solvent mixture further comprises: an effective
amount of a leveling agent to spread the aqueous-organic solvent
mixture on the substrate and provide substantially uniform contact
of the aqueous-organic solvent mixture with the substrate.
87. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 63 wherein the
aqueous-organic solvent mixture further comprises: an effective
amount of colloidal silica to provide the composition with from
about 0.1 to about 50 weight percent silica, based on the total of
solids present in the composition.
88. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 87 wherein the
aqueous-organic solvent mixture further comprises: an effective
amount of a leveling agent to spread the aqueous-organic solvent
mixture on the substrate and provide substantially uniform contact
of the aqueous-organic solvent mixture with the substrate.
89. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 88 wherein the amount of
water present in the aqueous-organic solvent mixture is an amount
sufficient to provide a substantially homogeneous mixture of
hydrolysis products and partial condensates of the epoxy functional
silane and the tetrafunctional silane.
90. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 89 wherein the
aqueous-organic solvent mixture further comprises an effective
amount of a catalyst to provide enhanced abrasion resistance to the
coating produced by curing the aqueous-organic solvent mixture.
91. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 90 wherein the effective
amount of a catalyst present in the aqueous-organic solvent mixture
is from about 0.1 to about 10 weight percent, based on the total
solids of the aqueous-organic solvent mixture.
92. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 90 wherein the
aqueous-organic solvent mixture further comprises from about 0.1 to
about 50 weight percent, based on the total of solids of the
aqueous-organic solvent mixture, of a mixture of hydrolysis
products and partial condensates of an alkyl silane represented by
the formula R.sup.9.sub.xSi(OR.sup.10).sub- .4'x where x is an
integer of 1, 2 or 3, R.sup.9 is H, an alkyl group containing from
1 to about 10 carbon atoms, a functionalized alkyl group, an
alkylene group, an aryl group, an alkoxypolyether group and
combinations thereof, R.sup.10 is H, an alkyl group containing from
1 to about 10 carbon atoms, an acetyl group and combinations
thereof.
93. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 63 wherein the
aqueous-organic solvent mixture further comprises: an effective
amount of a leveling agent to spread the aqueous-organic solvent
mixture on the substrate and provide substantially uniform contact
of the aqueous-organic solvent mixture with the substrate.
94. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 63 wherein the substrate
is formed of plastic, wood, ceramic, glass ceramic, glass, mineral
based, leather, paper, textile and metal materials.
95. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 63 further comprising:
treating the substrate to enhance adhesion of the substantially
transparent, abrasion resistant coating to the substrate.
96. The process for providing a substantially transparent, abrasion
resistant coating on a substrate of claim 63 wherein the curing of
the aqueous-organic solvent mixture coating to produce a
substantially transparent, abrasion-resistant coating on the
substrate is achieved by heating the substrate having the
aqueous-organic solvent mixture coating applied thereto to a
temperature of from about 50.degree. C. to about 200.degree. C. for
a period of time effective to cure the coating and provide the
substrate with a substantially transparent, substantially uniform
abrasion resistant coating having a Bayer number of at least 5.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] None.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable.
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The present invention relates to coating compositions, and
more particularly but not by way of limitation, to coating
compositions which, when cured, provide substantially transparent
coatings having enhanced abrasion resistance. In one aspect, the
present invention relates to a coating composition having improved
stability wherein the coating compositions are derived from
aqueous-organic solvent mixtures containing effective amounts of
epoxy functional silanes, tetrafunctional silanes and
multifunctional compounds such as multifunctional carboxylic acids,
multifunctional anhydrides, and mixtures thereof.
[0005] 2. Description of Prior Art
[0006] The prior art is replete with compositions which, when
applied to substrates and cured, provide transparent, abrasion
resistant coatings for the substrates. Such coatings are especially
useful for polymeric substrates where it is highly desirable to
provide substrates with abrasion resistant surfaces, with the
ultimate goal to provide abrasion resistant surfaces which are
comparable to glass. While the compositions of the prior art have
provided transparent coating compositions having improved abrasion
resistant properties, such prior art compositions are generally
lacking when compared to glass. Thus, a need has long existed for
improved compositions having improved stability and which, when
applied to a substrate, such as a polymeric substrate, and cured
provide transparent, highly abrasion resistant coatings. It is to
such compositions and processes by which such compositions are
manufactured and applied to substrates that the present invention
is directed.
BRIEF SUMMARY OF THE INVENTION
[0007] The present invention provides compositions having improved
stability which, when applied to a variety of substrates and cured,
form transparent coatings having superior abrasion resistant
properties. Broadly, the coating compositions of the present
invention comprise an aqueous-organic solvent mixture containing
from about 10 to about 99.9 weight percent, based on the total
solids of the composition, of a mixture of hydrolysis products and
partial condensates of an epoxy functional silane and a
tetrafunctional silane and from about 0.1 to about 30 weight
percent, based on the total solids of the composition, of a
multifunctional compound selected from the group consisting of
multifunctional carboxylic acids, multifunctional anhydrides and
combinations thereof. The epoxy functional silane and the
tetrafunctional silane are present in the aqueous-organic solvent
mixture in a molar ratio of from about 0.1:1 to about 5:1. The
coating compositions of the present invention may further include
from about 0.1 to about 50 weight percent of a mixture of
hydrolysis products and partial condensates of one or more alkyl
silanes, based on the total solids of the composition, and/or an
amount of colloidal silica or a metal oxide or combinations thereof
equivalent to from about 0.1 to about 50 weight percent solids,
based on the total solids of the composition.
[0008] It is an object of the present invention to provide coating
compositions having improved stability which form transparent
coatings upon curing. It is a further object of the present
invention to provide stable coating compositions which form
transparent coatings upon curing having improved abrasion
resistance.
[0009] Other objects, advantages and features of the present
invention will become apparent upon reading the following detailed
description in conjunction with the appended claims.
DETAILED DESCRIPTION OF THE INVENTION
[0010] The present invention relates to coating compositions having
improved stability which, when applied to a variety of substrates
and cured, form substantially transparent abrasion resistant
coatings having a Bayer number of at least 5 when tested in
accordance with the variation of the Oscillating Sand Test (ASTM
F735-81) hereinafter described.
[0011] For testing abrasion resistance of coated substrates, any of
a number of quantitative test methods may be employed, including
the Taber Test (ASTM D-4060), the Tumble Test and the Oscillating
Sand Test (ASTM F735-81). In addition, there are a number of
qualitative test methods that may be used for measuring abrasion
resistance, including the Steel Wool Test and the Eraser Test. In
the Steel Wool Test and the Eraser Test, sample coated substrates
are scratched under reproducible conditions (constant load,
frequency, etc.). The scratched test samples are then compared and
rated against standard samples. A semi-quantitative application of
these test methods involves the use of an instrument, such as a
Spectrophotometer or a Colorimeter, for measuring the scratches on
the coated substrate as a haze gain.
[0012] The measured abrasion resistance of a cured coating on a
substrate, whether measured by the Bayer Test, Taber Test, Steel
Wool Test, Eraser Test, Tumble Test, etc. is a function, in part,
of the cure temperature and cure time. In general, higher
temperatures and longer cure times result in higher measured
abrasion resistance. Normally, the cure temperature and cure time
are selected for compatibility with the substrate; although,
sometimes less than optimum cure temperatures and cure times are
used due to process and/or equipment limitations. It will be
recognized by those skilled in the art that other variables, such
as coating thickness and the nature of the substrate, will also
have an effect on the measured abrasion resistance. In general, for
each type of substrate and for each coating composition there will
be an optimum coating thickness. The optimum cure temperature, cure
time, coating thickness, and the like, can be readily determined
empirically by those skilled in the art.
[0013] Within the Ophthalmic Industry, the Oscillating Sand Test is
presently the most widely used and accepted method for measuring
abrasion resistance. Since the original ASTM application of the
Oscillating Sand Test was for testing flat polymeric sheets, the
test method has necessarily been modified for use with ophthalmic
lenses. There is currently no ASTM accepted standard (or other
industry standard) for this test as applied to ophthalmic lenses;
therefore, there are a number of basic variations of the
Oscillating Sand Test in practice.
[0014] In one particular variation of the Oscillating Sand Test, a
sand cradle is modified to accept coated sample lenses and uncoated
reference lenses. Typically, poly(diethylene glycol-bis-allyl
carbonate) lenses, hereinafter referred to as ADC lenses, are used
as the reference lenses. The lenses are positioned in the cradle to
allow a bed of abrasive material, either sand or a synthetically
prepared metal oxide, to flow back and forth across the lenses, as
the cradle oscillates back and forth at a fixed stroke, frequency
and duration.
[0015] In the test method employed to determine the abrasion
resistance of the coating compositions of the present invention, a
commercially available sand sold by CGM, Inc., 1463 Ford Road,
Bensalem, Pa., was used as the abrasive material. In this test, 877
grams of sifted sand (600 ml by volume) was loaded into a
9{fraction (5/16)}'.times.63/4' cradle fitted with four lenses. The
sand was sifted through a #5 Mesh screen (A.S.T.M.E.-11
specification) and collected on a #6 Mesh screen. Each set of four
lenses was subjected to a 4 inch stroke (the direction of the
stroke coinciding with the 9{fraction (5/16)}' length of the
cradle) at a frequency of 300 strokes per minute for a total of 3
minutes. The lens cradle was then repositioned by turning 180
degrees and then subjected to another 3 minutes of testing.
Repositioning of the cradle was used to reduce the impact of any
inconsistencies in the oscillating mechanism. The ADC reference
lenses used were Silor 70 mm plano FSV lenses, purchased through
Essilor of America, Inc. of St. Petersburg, Fla.
[0016] The haze generated on the lenses was then measured on a
Gardner XL-835 Colorimeter. The haze gain for each lens was
determined as the difference between the initial haze on the lenses
and the haze after testing. The ratio of the haze gain on the ADC
reference lenses to the haze gain on the coated sample lenses was
then reported as the resultant abrasion resistance of the coating
material. A ratio of greater than 1 indicates a coating which
provides greater abrasion resistance than the uncoated ADC
reference lenses. This ratio is commonly referred to as the Bayer
ratio, number or value; the higher the Bayer number, the higher the
abrasion resistance of the coating. Coatings produced by curing the
coating compositions of the present invention, when tested using
the Oscillating Sand Test method as described above, coated on
either polycarbonate or on ADC lenses, have been shown to provide
Bayer numbers which exceed 5. For testing coated samples, samples
coated on ADC lenses were cured at a temperature of 120.degree. C.
for a period of 3 hours. Samples coated on polycarbonate lenses
were cured at a temperature of 129.degree. C. for a period of 4
hours.
[0017] One who is skilled in the art will recognize that: (a) The
descriptions herein of coating systems which contain epoxy
functional silanes, tetrafunctional silanes, silanes which do not
contain an epoxy functional group, and the multifunctional
component refer to the incipient silane and multifunctional
components from which the coating system is formed, (b) when the
epoxy functional. silanes, tetrafunctional silanes, and silanes
which do not contain an epoxy functional group, are combined with
the aqueous-solvent mixture, partial or fully hydrolyzed species
will result, (c) the resultant fully or partially hydrolyzed
species will combine to form mixtures of multifunctional oligomeric
siloxane species, (d) these oligomers may or may not contain both
pendant hydroxy and pendant alkoxy moieties and will be comprised
of a silicon-oxygen matrix which contains both silicon-oxygen
siloxane linkages and silicon-oxygen multifunctional component
linkages, (e) these are dynamic oligomeric suspensions that undergo
structural changes which are dependent upon a multitude of factors
including; temperature, pH, water content, catalyst concentration,
and the like.
[0018] The coating compositions of the present invention comprise
an aqueous-organic solvent mixture containing from about 10 to
about 99.9 weight percent, based on the total solids of the
composition, of a mixture of hydrolysis products and partial
condensates of an epoxy functional silane and a tetrafunctional
silane and from about 0.1 to about 30 weight percent, based on the
total solids of the composition, of a multifunctional compound
selected from the group consisting of multifunctional carboxylic
acids, multifunctional anhydrides, and combinations thereof. It
will be recognized by those skilled in the art that the amount of
epoxy functional silane and the amount of tetrafunctional silane
employed to provide the mixture of hydrolysis products and partial
condensates of the epoxy functional silane and the tetrafunctional
silane can vary widely and will generally be dependent upon the
properties desired in the coating composition, the coating formed
by curing the coating composition, as well as the end use of the
substrate to which the coating composition is applied. Generally,
however, desirable results can be obtained where the epoxy
functional silane and a tetrafunctional silane are present in the
aqueous-solvent mixture in a molar ratio of from about 0.1:1 to
about 5:1. More desirably, the epoxy functional silane and the
tetrafunctional silane are present in the aqueous-solvent mixture
in a molar ratio of from about 0.1:1 to about 3:1.
[0019] While the presence of water in the aqueous-organic solvent
mixture is necessary to form hydrolysis products of the silane
components of the mixture, the actual amount can vary widely.
Essentially enough water is needed to provide a substantially
homogeneous coating mixture of hydrolysis products and partial
condensates of the epoxy functional silane and the tetrafunctional
silane which, when applied and cured on an article, provides a
substantially transparent coating with a Bayer number of at least 5
when using the method hereinbefore described. It will be recognized
by those skilled in the art that this amount of water can be
determined empirically.
[0020] The solvent constituent of the aqueous-organic solvent
mixture of the coating compositions of the present invention can be
any solvent or combination of solvents which is compatible with the
epoxy functional silane, the tetrafunctional silane and the
multifunctional component. For example, the solvent constituent of
the aqueous-organic solvent mixture may be an alcohol, an ether, a
glycol or a glycol ether, a ketone, an ester, a glycolether acetate
and mixtures thereof. Suitable alcohols can be represented by the
formula ROH where R is an alkyl group containing from 1 to about 10
carbon atoms. Some examples of alcohols useful in the application
of this invention are methanol, ethanol, propanol, isopropanol,
butanol, isobutanol, secondary butanol, tertiary butanol,
cyclohexanol, pentanol, octanol, decanol, and mixtures thereof.
[0021] Suitable glycols, ethers, glycol ethers can be represented
by the formula R.sup.1--(OR.sup.2).sub.x--OR.sup.1 where x is 0, 1,
2, 3 or 4, R.sup.1 is hydrogen or an alkyl group containing from 1
to about 10 carbon atoms and R.sup.2 is an alkylene group
containing from 1 to about 10 carbon atoms and combinations
thereof.
[0022] Examples of glycols, ethers and glycol ethers having the
above-defined formula and which may be used as the solvent
constituent of the aqueous-organic solvent mixture of the coating
compositions of the present invention are di-n-butylether, ethylene
glycol dimethyl ether, propylene glycol dimethyl ether, propylene
glycol methyl ether, dipropylene glycol methyl ether, tripropylene
glycol methyl ether, dipropylene glycol dimethyl ether,
tripropylene glycol dimethyl ether, ethylene glycol butyl ether,
diethylene glycol butyl ether, ethylene glycol dibutyl ether,
ethylene glycol methyl ether, diethylene glycol ethyl ether,
diethylene glycol dimethyl ether, ethylene glycol ethyl ether,
ethylene glycol diethyl ether, ethylene glycol, diethylene glycol,
triethylene glycol, propylene glycol, dipropylene glycol,
tripropylene glycol, butylene glycol, dibutylene glycol,
tributylene glycol and mixtures thereof. In addition to the above,
cyclic ethers such as tetrahydrofuran and dioxane are suitable
ethers for the aqueous-organic solvent mixture.
[0023] Examples of ketones suitable for the aqueous-organic solvent
mixture are acetone, diacetone alcohol, methyl ethyl ketone,
cyclohexanone, methyl isobutyl ketone and mixtures thereof.
[0024] Examples of esters suitable for the aqueous-organic solvent
mixture are ethyl acetate, n-propyl acetate, n-butyl acetate and
combinations thereof.
[0025] Examples of glycolether acetates suitable for the
aqueous-organic solvent mixture are propylene glycol methyl ether
acetate, dipropylene glycol methyl ether acetate, ethyl
3-ethoxyproprionate, ethylene glycol ethyl ether acetate and
combinations thereof.
[0026] The epoxy functional silane useful in the formulation of the
coating compositions of the present invention can be any epoxy
functional silane which is compatible with the tetrafunctional
silane and the multifunctional component of the coating composition
and which provides a coating composition which, upon curing,
produces a substantially transparent, abrasion resistant coating
having a Bayer number of at least about 5 when employing the test
method hereinbefore described. Generally, such epoxy functional
silanes are represented by the formula
R.sup.3.sub.xSi(OR.sup.4).sub.4-x where x is an integer of 1, 2 or
3, R.sup.3 is H, an alkyl group, a functionalized alkyl group, an
alkylene group, an aryl group, an alkyl ether, and combinations
thereof containing from 1 to about 10 carbon atoms and having at
least 1 epoxy functional group, and R.sup.4 is H, an alkyl group
containing from 1 to about 5 carbon atoms, an acetyl group, a
--Si(OR.sup.5).sub.3-yR.sup.6.sub.y group where y is an integer of
0, 1, 2, or 3, and combinations thereof where R.sup.5 is H, an
alkyl group containing from 1 to about 5 carbon atoms, an acetyl
group, or another --Si(OR.sup.5).sub.3-yR.sup.6.sub.y group and
combinations thereof, and R.sup.6 is H, an alkyl group, a
functionalized alkyl group, an alkylene group, an aryl group, an
alkyl ether, and combinations thereof containing from 1 to about 10
carbon atoms which may also contain an epoxy functional group.
[0027] Examples of such epoxy functional silanes are
glycidoxymethyltrimethoxysilane, 3-glycidoxypropyltrihydroxysilane,
3-glycidoxypropyldimethylhydroxysilane,
3-glycidoxypropyltrimethoxysilane- ,
3-glycidoxypropyltriethoxysilane,
3-glycidoxypropyldimethoxymethylsilane- ,
3-glycidoxypropyldimethylmethoxysilane,
3-glycidoxypropyltributoxysilane- ,
1,3-bis(glycidoxypropyl)tetramethyldisiloxane,
1,3-bis(glycidoxypropyl)t- etramethoxydisiloxane,
1,3-bis(glycidoxypropyl)-1,3-dimethyl-1,3-dimethoxy- disiloxane,
2,3-epoxypropyltrimethoxysilane, 3,4-epoxybutyltrimethoxysilan- e,
6,7-epoxyheptyltrimethoxysiiane, 9,10-epoxydecyltrimethoxysilane,
1,3-bis (2,3-epoxypropyl) tetramethoxydisiloxane, 1,3-bis
(6,7-epoxy-heptyl) tetramethoxydisiloxane, 2-(3,4-epoxycyclohexyl)
ethyltrimethoxysilane, and the like.
[0028] The tetrafunctional silanes useful in the formulation of the
coating compositions of the present invention are represented by
the formulas Si(OR.sup.7).sub.4 where R.sup.7 is H, an alkyl group
containing from 1 to about 5 carbon atoms and ethers thereof, a
--Si(OR.sup.8).sub.3 group where R.sup.8 is a H, an alkyl group
containing from 1 to about 5 carbon atoms and ethers thereof, or
another --Si(OR.sup.8).sub.3 group and combinations thereof.
Examples of tetrafunctional silanes represented by the formula
Si(OR.sup.7).sub.4 are tetramethyl orthosilicate, tetraethyl
orthosilicate, tetrapropyl orthosilicate, tetraisopropyl
orthosilicate, tetrabutyl ortho-silicate, tetraisobutyl
orthosilicate, tetrakis (methoxyethoxy)-silane,
tetrakis(methoxypropoxy)silane, tetrakis(ethoxyethoxy)-silane,
tetrakis(methoxyethoxyethoxy)silane, trimethoxyethoxy-silane,
dimethoxydiethoxysilane, triethoxymethoxysilane,
poly-(dimethoxysiloxane), poly(diethoxysiloxane),
poly(dimethoxydiethoxys- iloxane),
tetrakis(trimethoxysiloxy)silane, tetrakis-(triethoxysiloxy)sila-
ne, and the like. In addition to the R.sup.7 and R.sup.8
substituants described above for the tetrafunctional silane,
R.sup.7 and R.sup.8 taken with oxygen (OR.sup.7) and (OR.sup.8) can
be carboxylate groups. Examples of tetrafunctional silanes with
carboxylate functionalities are silicon tetracetate, silicon
tetrapropionate and silicon tetrabutyrate.
[0029] The multifunctional compounds which can be employed in the
formulation of the coating compositions of the present invention
can be any multifunctional carboxylic acid, multifunctional
anhydride and combinations thereof which is compatible with the
epoxy functional silane and the tetrafunctional silanes of the
coating compositions and which is capable of interacting with the
hydrolysis products and partial condensates of the epoxy functional
silane and the tetrafunctional silane to provide a coating
composition which, upon curing, produces a substantially
transparent, abrasion resistant coating having a Bayer number of at
least 5 when employing the test method hereinbefore described.
[0030] Examples of multifunctional carboxylic acids which can be
employed as the multifunctional compound in the compositions of the
present invention include malic acid, aconitic acid (cis, trans),
itaconic acid, succinic acid, malonic acid, glutaric acid, adipic
acid, pimelic acid, suberic acid, azelaic acid, sebacic acid,
cyclohexyl succinic acid, 1,3,5 benzene tricarboxylic acid, 1,2,4,5
benzene tetracarboxylic acid, 1,4 cyclohexanedicarboxylic acid,
1,3-cyclohexanedicarboxylic acid, 1,1-cyclohexanediacetic acid,
1,3-cyclohexanediacetic acid, 1,3,5-cyclohexanetricarboxylic acid
and unsaturated dibasic acids such as fumaric acid and maleic acid
and combinations thereof.
[0031] Examples of multifunctional anhydrides which can be employed
as the multi-functional compound in the coating compositions of the
present invention include the cyclic anhydrides of the above
mentioned dibasic acids such as succinic anhydride, itaconic
anhydride, glutaric anhydride, trimellitic anhydride, pyromellitic
anhydride, phthalic anhydride and maleic anhydride and combinations
thereof.
[0032] The nature of the interaction between the epoxy functional
silane, the tetrafunctional silane and the multifunctional
compound, and the effect that such interaction has on the abrasion
resistance of the cured coating is not fully understood. It is
believed, however, that the multifunctional compound acts as more
than just a hydrolysis catalyst for the silanes. In this regard, it
can be proposed that the multifunctional compound has specific
activity towards the epoxy functionality on the silane. The
reaction of the epoxy groups with carboxylic acids is well known
and can occur under either acidic or basic conditions. The
carboxylate groups on the multifunctional compound will also most
likely have some activity towards the silicon atoms in the matrix;
and such interaction may be through normal exchange reactions with
residual alkoxide and hydroxide groups or, alternatively, through
some hypervalent state on the silicon atoms. The actual interaction
involving the multifunctional compound may, in fact, be a
combination of all of the above possibilities, the result of which
would be a highly crosslinked matrix. Thus, the matrix is enhanced
through extended linkages involving the multifunctional
compound.
[0033] As examples of the significance of these possible
interactions, coatings prepared with non-multifunctional compounds,
for example acetic acid, fail to show the same high degree of
stability and abrasion resistance as obtained through the use of
the multifunctional compounds. In this case, a non-multifunctional
acid would have the same utility in the coating composition as a
hydrolysis catalyst for the silanes, but could not provide the
extended linkages presumed to be possible with the multifunctional
compounds.
[0034] The coating compositions of the present invention are also
very stable with respect to aging, both in terms of performance and
solution stability. The aging of the coating compositions is
characterized by a gradual increase in viscosity which eventually
renders the coating compositions unusable due to processing
constraints. Aging studies have shown that the coating compositions
of the present invention, when stored at temperatures of 5.degree.
C. or lower, have usable shelf lives of 3-4 months. During this
period, the abrasion resistance of the cured coatings does not
significantly decrease with time. Further, such studies have shown
that stability of the coating compositions is dependent on the
relative concentrations of the epoxy functional silane, the
tetrafunctional silane and the multifunctional compound. In
general, higher concentrations of the epoxy functional silane and
the multifunctional compound contribute to increased stability of
the coating mixture. Thus, in addition to providing enhanced
abrasion resistance to the cured coatings, the multifunctional
compound contributes to the overall stability of the coating
compositions.
[0035] While the coating compositions produced by the unique
combination of an epoxy functional silane, a tetrafunctional silane
and a multifunctional compound provide the primary basis for the
high abrasion resistance of coatings prepared by curing such
coating compositions, the coating compositions may additionally
include other materials to: (a) enhance the stability of the
coating compositions; (b) increase the abrasion resistance of cured
coatings produced by the coating compositions; (c) enhance
processing of the coating compositions; and (d) provide other
desirable properties of the cured coating produced from the coating
compositions.
[0036] The coating compositions of the present invention may
further include from about 0.1 to about 50 weight percent, based on
the weight of total solids of the coating compositions, of a
mixture of hydrolysis products and partial condensates of one or
more alkyl silanes (i.e, trifunctional silanes, difunctional
silanes, monofunctional silanes, and mixtures thereof, hereinafter
referred to as silane additives). The silane additives which can be
incorporated into the coating compositions of the present invention
have the formula R.sup.9.sub.xSi(OR.sup.10).sub.- 4-x where x is a
number of 1, 2 or 3; R.sup.9 is H, or an alkyl group containing
from 1 to about 10 carbon atoms, a functionalized alkyl group, an
alkylene group, an aryl group an alkoxypolyether group and
combinations thereof; R.sup.10 is H, an alkyl group containing from
1 to about 10 carbon atoms, an acetyl group; and combinations
thereof. Examples of silane additives represented by the
above-defined formula are methyltrimethoxysilane,
ethyltrimethoxysilane, propyltrimethoxysilane,
butyltrimethoxysilane, isobutyltrimethoxysilane,
hexyltrimethoxysilane, octyltrimethoxysilane,
decyltrimethoxysilane, cyclohexyltrimethoxysilane,
cyclohexylmethyltrimethoxysilane,
3-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane,
allyltrimethoxysilane, dimethyldimethoxysilane,
2-(3-cyclohexenyl)ethyltrimethoxysilane,
3-cyanopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane,
2-chloroethyltrimethoxysilane, phenethyltrimethoxysilane,
3-mercaptopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane,
phenyltrimethoxysilane, 3-isocyanopropyltrimethoxysilane,
N-(2-aminoethyl)-3-aminopropyltrimethox- ysilane,
4-(2-aminoethylaminomethyl)phenethyltrimethoxysilane,
chloromethyltriethoxysilane, 2-chloroethyltriethoxysilane,
3-chloropropyltriethoxysilane, phenyltriethoxysilane,
ethyltriethoxysilane, propyltriethoxysilane, butyltriethoxysilane,
isobutyltriethoxysilane, hexyltriethoxysilane,
octyltriethoxysilane, decyltriethoxysilane,
cyclohexyltriethoxysilane, cyclohexylmethyltriethox- ysilane,
3-methacryloxypropyltriethoxysilane, vinyltriethoxysilane,
allyltriethoxysilane, [2-(3-cyclohexenyl)ethyltriethoxysilane,
3-cyanopropyltriethoxysilane,
3-methacrylamidopropyltriethoxysilane,
3-methoxypropyltrimethoxysilane, 3-ethoxypropyltrimethoxysilane,
3-propoxypropyltrimethoxysilane, 3-methoxyethyltrimethoxysilane,
3-ethoxyethyltrimethoxysilane, 3-propoxyethyltrimethoxysilane,
2-[methoxy-(polyethyleneoxy)propyl]heptamethyltrisiloxane,
[methoxy(polyethyleneoxy)propyl]trimethoxysilane,
[methoxy(polyethyleneox- y)ethyl]trimethoxysilane,
[methoxy(polyethyleneoxy)propyl]-triethoxysilane- ,
[rethoxy(polyethyleneoxy)ethyl]triethoxysilane.
[0037] The selection of the silane additive, as well as the amount
of such silane additive incorporated into the coating compositions
will depend upon the particular properties to be enhanced or
imparted to either the coating composition or the cured coating
composition. For example, when the difunctional silane
dimethyldimethoxysilane is utilized as the silane additive and
incorporated into the coating composition in an amount of about 10%
or less, based on the total solids of the composition, the
viscosity increase is greatly reduced during aging of the coating
composition, without greatly affecting the resultant abrasion
resistance of the cured coating.
[0038] In certain applications, it is useful to add colloidal
silica to the coating composition. Colloidal silica is commercially
available under a number of different tradename designations,
including Nalcoag.RTM. (Nalco Chemical Co., Naperville, Ill.);
Nyacol.RTM. (Nyacol Products, Inc., Ashland, Mass.); Snowtex.RTM.
(Nissan Chemical Industries, LTD., Tokyo, Japan); Ludox.RTM.
(DuPont Company, Wilmington, Del.); and Highlink OG.RTM. (Hoechst
Celanese, Charlotte, N.C.). The colloidal silica is an aqueous or
organic solvent dispersion of particulate silica and the various
products differ principally by particle size, silica concentration,
pH, presence of stabilizing ions, solvent makeup, and the like. It
is understood by those skilled in the art that substantially
different product properties can be obtained through the selection
of different colloidal silicas.
[0039] Colloidal silica, when added to a coating composition, is
considered a reactive material. The surface of the silica is
covered with silicon bound hydroxyls, some of which are
deprotonated, which can interact with materials in the coating
composition. The extent of these interactions is dictated by a
variety of factors, including solvent system, pH, concentration,
and ionic strength. The manufacturing process further affects these
interactions. It is thus recognized by those skilled in the art,
that colloidal silica can be added into a coating formulation in
different ways with different results.
[0040] In the coating compositions of the present invention,
colloidal silica can be added into the coating compositions in a
variety of different ways. In some instances, it is desirable to
add the colloidal silica in the last step of the reaction sequence.
In other instances, colloidal silica is added in the first step of
the reaction sequence. In yet other instances, colloidal silica can
be added in an intermediate step in the sequence.
[0041] It has been observed that the addition of colloidal silica
to the coating compositions of the present invention can further
enhance the abrasion resistance of the cured coating compositions
and can further contribute to the overall stability of the coating
compositions. The most significant results have been achieved with
the use of aqueous basic colloidal silica, that is, aqueous
mixtures of colloidal silica having a pH greater than 7. In such
cases, the high pH is accompanied by a higher concentration of a
stabilizing counterion, such as the sodium cation. Cured coatings
formulated from the coating compositions of the present invention
which contain basic colloidal silicas have shown abrasion
resistance comparable to those of a catalyzed coating composition
of the present invention (that is, a composition of hydrolysis
products and partial condensates of an epoxy functional silane, a
tetrafunctional silane, a multi-functional compound and a catalyst
such as sodium hydroxide), but the coating compositions containing
colloidal silica have enhanced stability with respect to the
catalyzed compositions which do not contain colloidal silica.
[0042] In the same manner, it is also possible to add other metal
oxides into the coating compositions of the present invention. Such
additions may be made instead of, or in addition to, any colloidal
silica additions. Metal oxides may be added to the inventive
coatings to provide or enhance specific properties of the cured
coating, such as abrasion resistance, refractive index, antistatic,
anti-reflectance, weatherability, etc. It will be recognized by
those skilled in the art that similar types of considerations that
apply to the colloidal silica additions will also apply more
generally to the metal oxide additions.
[0043] Examples of metal oxides which may be used in the coating
compositions of the present invention include silica, zirconia,
titania, ceria, tin oxide and mixtures thereof.
[0044] The amount of colloidal silica incorporated into the coating
compositions of the present invention can vary widely and will
generally depend on the desired properties of the cured coating
produced from the coating compositions, as well as the desired
stability of the coating compositions. Similarly, the amount of
metal oxides incorporated into the coating compositions of the
present invention can vary widely and will generally depend on the
desired properties of the cured coating produced from the coating
compositions, as well as the desired stability of the coating
compositions.
[0045] When colloidal silica and/or metal oxides are added, it is
desirable to add from about 0.1 to about 50 weight percent of
solids of the colloidal silica and/or metal oxides, based on the
total solids of the composition, to the coating compositions of the
present invention. The colloidal silica and/or metal oxides will
generally have a particle size in the range of 2 to 150
millimicrons in diameter, and more desirably, a particle size in
the range of from about 2 to 50 millimicrons.
[0046] Although a catalyst is not an essential ingredient of the
present invention, the addition of a catalyst can affect abrasion
resistance and other properties of the coating including stability,
tinting capacity, porosity, cosmetics, caustic resistance, water
resistance and the like. The amount of catalyst used can vary
widely, but when present will generally be in an amount sufficient
to provide from about 0.1 to about 10 weight percent, based on the
total solids of the composition.
[0047] Examples of catalysts which can be incorporated into the
coating compositions of the present invention are (i) metal
acetylacetonates, (ii) diamides, (iii) imidazoles, (iv) amines and
ammonium salts, (v) organic sulfonic acids and their amine salts,
(vi) alkali metal salts of carboxylic acids, (vii) alkali metal
hydroxides and (viii) fluoride salts. Thus, examples of such
catalysts include for group (i) such compounds as aluminum, zinc,
iron and cobalt acetylacetonates; group (ii) dicyandiamide; for
group (iii) such compounds as 2-methylimidazole,
2-ethyl-4-methylimidazole and l-cyanoethyl-2-propylimidazole; for
group (iv), such compounds as benzyldimethylamine, and
1,2-diaminocyclohexane; for group (v), such compounds as
trifluoromethanesulfonic acid; for group (vi), such compounds as
sodium acetate, for group (vii), such compounds as sodium
hydroxide, and potassium hydroxide; and for group (viii), tetra
n-butyl ammonium fluoride, and the like.
[0048] An effective amount of a leveling or flow control agent can
be incorporated into the composition to more evenly spread or level
the composition on the surface of the substrate and to provide
substantially uniform contact with the substrate. The amount of the
leveling or flow control agent can vary widely, but generally is an
amount sufficient to provide the coating composition with from
about 10 to about 5,000 ppm of the leveling or flow control agent.
Any conventional, commercially available leveling or flow control
agent which is compatible with the coating composition and the
substrate and which is capable of leveling the coating composition
on a substrate and which enhances wetting between the coating
composition and the substrate can be employed. The use of leveling
and flow control agents is well known in the art and has been
described in the "Handbook of Coating Additives" (ed. Leonard J.
Calbo, pub. Marcel Dekker), pg 119-145.
[0049] Examples of such leveling or flow control agents which can
be incorporated into the coating compositions of the present
invention include organic polyethers such as TRITON X-100, X-405,
N-57 from Rohm and Haas, silicones such as Paint Additive 3, Paint
Additive 29, Paint Additive 57 from Dow Corning, SILWET L-77, and
SILWET L7600 from OSi Specialties, and fluorosurfactants such as
FLUORAD FC-171, FLUORAD FC-430 and FLUORAD FC-431 from 3M
Corporation.
[0050] In addition, other additives can be added to the coating
compositions of the present invention in order to enhance the
usefulness of the coating compositions or the coatings produced by
curing the coating compositions. For example, ultraviolet
absorbers, antioxidants, and the like can be incorporated into the
coating compositions of the present invention, if desired.
[0051] The coating compositions of the present invention can be
prepared by a variety of processes to provide stable coating
compositions which, upon curing, produce substantially transparent
coatings having enhanced abrasion resistance. For example, the
epoxy functional silane, the tetrafunctional silane and the
multifunctional compound can be added to the aqueous-organic
solvent solution and stirred for a period of time effective to
produce a coating composition having improved stability. When
cured, such coating compositions have Bayer numbers ranging from
about 6 to about 8 when employing the test method hereinbefore
described. However, by incorporating a catalyst into the
aqueous-organic solvent mixtures containing the epoxy functional
silane, the tetrafunctional silane and the multifunctional
compound, the Bayer numbers of the cured coatings produced from
such coating compositions are increased so as to range from about 8
to about 15 when employing the test method hereinbefore
described.
[0052] When an aqueous hydrolyzate of the epoxy functional silane
is mixed with a solution of the multifunctional compound and
combined with the tetrafunctional silane a coating composition is
formed which when cured has a Bayer value of about 7 when employing
the test method herein before described.
[0053] When a tetrafunctional silane hydrolyzate is formed in the
presence of the multifunctional compound or other acid and the
aqueous-organic mixture, and the epoxy functional component is
added to this mixture, a coating composition is obtained which when
cured provides a Bayer value of about 7 when employing the test
method herein before described.
[0054] When a mixture of the tetrafunctional silane and the
multifunctional compound is hydrolyzed and treated with an
effective amount of sodium hydroxide and then admixed with an
aqueous hydrolyzate of the epoxy functional silane, the resulting
cured coating composition has a Bayer value of about 14 when
employing the test method herein before described.
[0055] From the above, it becomes clear to those skilled in the art
that various methods can be employed for producing the coating
compositions of the present invention, and that such compositions,
when cured, provide coatings having improved abrasion resistance.
Further, the coating compositions have a desired stability which
enhances their usefulness. However, by altering the method of
preparing such compositions, product properties, such as stability
and abrasion resistance, i.e., Bayer number, can be affected.
[0056] The compositions of the invention can be applied to solid
substrates by conventional methods, such as flow coating, spray
coating, curtain coating, dip coating, spin coating, roll coating,
etc. to form a continuous surface film. Any substrate compatible
with the compositions can be coated with the compositions, such as
plastic materials, wood, paper, metal, printed surfaces, leather,
glass, ceramics, glass ceramics, mineral based materials and
textiles. The compositions are especially useful as coatings for
synthetic organic polymeric substrates in sheet or film form, such
as acrylic polymers, poly(ethyleneterephthalate), polycarbonates,
polyamides, polyimides, copolymers of acrylonitrile-styrene,
styrene-acrylonitrile-butadiene copolymers, polyvinyl chloride,
butyrates, polyethylene and the like. Transparent polymeric
materials coated with these compositions are useful as flat or
curved enclosures, such as windows, skylights and windshields,
especially for transportation equipment. Plastic lenses, such as
acrylic or polycarbonate ophthalmic lenses, can also be coated with
the compositions of the invention.
[0057] By choice of proper formulation, application conditions and
pretreatment (including the use of primers) of the substrate, the
coating compositions of the present invention can be adhered to
substantially all solid surfaces. Abrasion resistant coatings
having Bayer numbers of at least 5 employing the test method
hereinbefore described can be obtained by heat curing at
temperatures in the range of 50.degree. C. to 200.degree. C. for a
period of from about 5 minutes to 18 hours. The coating thickness
can be varied by means of the particular application technique, but
coatings having a thickness of from about 0.5 to 20 microns, and
more desirably from about 1-10 microns, are generally utilized.
[0058] In order to further illustrate the present invention, the
following examples are given. However, it is to be understood that
the examples are for illustrative purposes only and are not to be
construed as limiting the scope of the subject invention. The
abrasion resistant properties of the coatings produced by curing
the coating compositions prepared in accordance with the following
examples were determined using the modification of the Oscillating
Sand Test method (ASTM F735-81) hereinbefore described.
EXAMPLES
Procedures
[0059] A. Etched poly(diethylene glycol-bis-allyl carbonate) lenses
(referred to as ADC lenses) were used for coating and testing. The
ADC lenses were etched by contact with a 10% potassium hydroxide
solution containing propylene glycol methyl ether and water for a
period of about 10 minutes. The propylene glycol methyl ether and
water were present in the potassium hydroxide solution in a 1:1
volume ratio. The coating of the lenses with the coating
compositions was achieved by dip coating the etched lenses at a
withdrawal rate of 6 inches per minute. The coated lenses were then
cured at 120.degree. C. for 3 hours. The lenses were tested using
the variation of the oscillating sand method hereinbefore described
and a Bayer number was determined for each coating.
[0060] B. Primed polycarbonate lenses (referred to as PC lenses)
were used for coating and testing. The PC lenses were primed with
SDC Primer XF-1107 (commercially available from SDC Coatings, Inc.,
Anaheim, Calif.) using a withdrawal rate of 2 inches per minute
followed by a 30 minute air dry to provide about a 0.5 micron prime
coat. The coating of the lenses with the coating compositions was
achieved by dip coating the primed lenses at a withdrawal rate of
18 inches per minute. The coated lenses were then cured at
130.degree. C. for 4 hours. The lenses were tested using the
variation of the Oscillating Sand Test method hereinbefore
described and a Bayer number was determined for each coating.
Example 1A
[0061] 464 grams of 3-glycidoxypropyltrimethoxysilane were added
slowly to 767 grams of deionized water while stirring. The aqueous
3-glycidoxypropyltrimethoxysilane mixture was stirred for
approximately one hour. 69.6 grams of itaconic acid dissolved in
767 grams of propylene glycol methyl ether were then added
streamwise to the aqueous 3-glycidoxypropyltrimethoxysilane
mixture. The mixture was then stirred for 30 minutes, and then 1021
grams of tetraethyl orthosilicate were slowly added to provide a
resulting admixture which was stirred overnight to produce a
coating composition.
[0062] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 2.1 microns. The coated lenses were then
subjected to the modified Oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating compositions prepared employing the procedures set
forth in this example had a Bayer number of about 6.7.
Example 1B
[0063] 380 grams of the coating composition from Example 1A were
treated with 0.9 grams of benzyldimethylamine and stirred for about
2 hours to produce a coating composition.
[0064] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 2.3 microns. The coated lenses were then
subjected to the modified Oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating compositions prepared employing the procedures set
forth in this example had a Bayer number of about 8.3.
Example 1C
[0065] 380 grams of the coating composition from Example 1A were
treated with 1.2 grams of a 19% aqueous solution of sodium
hydroxide to produce a coating composition.
[0066] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 2.4 microns. The coated lenses were then
subjected to the modified Oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating compositions prepared employing the procedures set
forth in this example had a Bayer number of about 10.5.
[0067] Examples 1B-1C illustrate the optional use of a catalyst
with the coating composition of Example 1A wherein the abrasion
resistance is improved when a catalyst is incorporated into the
coating composition.
Example 2A
[0068] A) 496 grams of 3-glycidoxypropyltrimethoxysilane were added
to 820 grams of deionized water. The aqueous
3-glycidoxypropyltrimethoxysilane mixture was stirred for
approximately one hour.
[0069] B) 200 grams of propylene glycol methyl ether and 18.2 grams
of glutaric acid were added to 319 grams of the aqueous
3-glycidoxypropyltrimethoxysilane mixture from step A above and
stirred for approximately 15 minutes to produce an admixture. 264.5
grams of tetraethyl orthosilicate were added to this admixture and
stirred approximately 17 hours to produce a coating
composition.
[0070] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 2.1 micron. The coated lenses were then
subjected to the modified Oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating compositions prepared employing the procedures set
forth in this example had a Bayer number of about 7.9.
Example 2B
[0071] 400 grams of the coating composition from Example 2A were
treated with 0.9 grams of benzyldimethylamine and stirred about 6
hours to produce a coating composition.
[0072] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 2.1 microns. The coated lenses were then
subjected to the modified oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating compositions prepared employing the procedures set
forth in this example had a Bayer number of about 12.2.
Example 3A
[0073] 200 grams of propylene glycol methyl ether and 13.7 grams of
succinic anhydride were added to 319 grams of the aqueous
3-glycidoxypropyltrimethoxysilane mixture (Step A) of Example 2A
and allowed to stir for approximately 15 minutes to produce an
admixture. 264.5 grams of tetraethyl orthosilicate were added to
the admixture and stirred for approximately 17 hours to produce a
coating composition.
[0074] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 2.1 microns. The coated lenses were then
subjected to the modified oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating compositions prepared employing the procedures set
forth in this example had a Bayer number of about 6.2.
Example 3B
[0075] 400 grams of the coating composition from Example 3A were
treated with 0.9 grams of benzyldimethylamine and stirred for
approximately 6 hours to produce a coating composition.
[0076] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 2.1 microns. The coated lenses were then
subjected to the modified Oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating compositions prepared employing the procedures set
forth in this example had a Bayer number of about 14.4.
Example 4A (Comparative Example)
[0077] 116 grams of 3-glycidoxypropyltrimethoxysilane were added
slowly to 191.8 grams of deionized water. The aqueous
3-glycidoxypropyltrimethoxysi- lane mixture was then stirred for
approximately one hour. 16 grams of acetic acid in 191.8 grams of
propylene glycol methyl ether were then added streamwise to the
aqueous 3-glycidoxypropyltrimethoxysilane mixture. The mixture was
then stirred for 15 minutes, and 255.3 grams of tetraethyl
orthosilicate were slowly added to provide a resulting admixture
which was stirred approximately 17 hours to produce a coating
composition.
[0078] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 2.1 microns. The coated lenses were then
subjected to the modified Oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating compositions prepared employing the procedures set
forth in this example had a Bayer number of about 4.4.
[0079] Example 4 in contrast with Examples 1A, 2A, and 3A shows the
importance of the multifunctional compound with respect to
obtaining Bayer numbers of at least 5 when such coating
compositions are tested using the modified Oscillating Sand Test
method hereinbefore described.
Example 5
[0080] 378 grams of 3-glycidoxypropyltrimethoxysilane were added to
653 grams of deionized water and stirred for about 18 hours. 30.8
grams of a 12 weight percent solution of itaconic acid in propylene
glycol methyl ether were added to 98.5 grams of the aqueous
3-glycidoxypropyltrimethoxy- silane mixture with stirring. 100.8
grams of tetra-n-propyl orthosilicate were then added. The mixture
was stirred 12 hours and 19 grams of propylene glycol methyl ether
were added to produce a coating composition. The coating
composition were aged 7 days at 5.degree. C.
[0081] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 2.1 microns. The coated lenses were then
subjected to the modified Oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating compositions prepared employing the procedures set
forth in this example had a Bayer number of about 8.6.
[0082] Example 5 illustrates the use of a tetrafunctional silane
other than tetraethyl orthosilicate and shows the generality of the
present invention with respect to the tetrafunctional silane.
Example 6A (Comparative Example)
[0083] 116 grams of 3-glycidoxypropyltrimethoxysilane were added to
191.8 grams of deionized water. The aqueous
3-glycidoxypropyltrimethoxysilane mixture was stirred for
approximately 1 hour. 17.4 grams of itaconic acid in 191.8 grams of
propylene glycol methyl ether were added streamwise and stirred
approximately 15 minutes to form an admixture. 216.6 grams of Nalco
N-1042 colloidal silica were added and stirred approximately 17
hours to form a coating composition.
[0084] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 2 microns. The coated lenses were then subjected
to the modified Oscillating Sand Test method hereinbefore described
and it was determined that the etched ADC lenses coated with the
coating composition prepared employing the procedures set forth in
this Example had a Bayer number of about 3.0.
Example 6B (Comparative Example)
[0085] 0.9 grams of benzyldimethylamine were added to 380 grams of
the coating composition of Example 6A and allowed to stir for about
2 hours to form a coating composition.
[0086] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 2 microns. The coated lenses were then subjected
to the modified Oscillating Sand Test method hereinbefore described
and it was determined that the etched ADC lenses coated with the
coating composition prepared employing the procedures set forth in
this Example had a Bayer number of about 2.4.
[0087] Examples 6A and 6B illustrate the importance of the presence
of the tetrafunctional silane in the coating compositions of the
present invention with respect to obtaining Bayer numbers of at
least 5 on the cured coating when such coating compositions are
tested using the modified Oscillating Sand Test method hereinbefore
described.
Example 7
[0088] 118.5 grams of tetraethyl orthosilicate were added dropwise
to 9.1 grams of itaconic acid, 100.9 grams of water and 100.9 grams
of propylene glycol methyl ether which were being stirred to form
an aqueous-organic solvent mixture. The aqueous-organic solvent
mixture was stirred for four hours. 67.2 grams of
3-glycidoxypropyltrimethoxysilane were added dropwise and stirred
about 14 hours to form an admixture. 0.03 grams of a silicone
leveling agent (PA-57 from Dow Corning, Midland, Mich.) in 0.27
grams of propylene glycol methyl ether were added to form a coating
composition.
[0089] The coating composition was applied to primed PC lenses
according to Procedure B to provide a cured coating. The coated
lenses were then subjected to the modified Oscillating Sand Test
method hereinbefore described and it was determined that the primed
PC lenses coated with the coating compositions prepared employing
the procedures set forth in this example had a Bayer number of
about 6.4.
Example 8
[0090] 86.1 grams of tetraethyl orthosilicate were added dropwise
to 10.6 grams of itaconic acid, 112.5 grams of water and 112.5
grams of propylene glycol methyl ether which were being stirred to
form an aqueous-organic solvent mixture. The aqueous-organic
solvent mixture was stirred for four hours. 78.3 grams of
3-glycidoxypropyltrimethoxysilane were added dropwise and stirred
about 14 hours to form an admixture. 0.03 grams of a silicon
leveling agent (PA-57) in 0.27 grams of propylene glycol methyl
ether were added to form a coating composition.
[0091] The coating composition was applied to the primed PC lenses
according to Procedure B to provide a coating having a thickness of
about 5.3 microns. The coated lenses were then subjected to the
modified Oscillating Sand Test method hereinbefore described and it
was determined that the primed PC lenses coated with the coating
compositions prepared employing the procedures set forth in this
example had a Bayer number of about 5.3.
Example 9
[0092] 74.8 grams of tetraethyl orthosilicate were added dropwise
to 9.1 grams of itaconic acid, 114.6 grams of water and 114.6 grams
of propylene glycol methyl ether which were being stirred to form
an aqueous-organic solvent mixture. The aqueous-organic solvent
mixture was stirred for four hours. 84.8 grams of
3-glycidoxypropyltrimethoxysilane were added dropwise and stirred
about 14 hours to form an admixture. 0.03 grams of a silicone
leveling agent (PA-57) in 0.27 grams of propylene glycol methyl
ether were added to form a coating composition.
[0093] The coating composition was applied to the primed PC lenses
according to Procedure B to provide a cured coating. The coated
lenses were then subjected to the modified Oscillating Sand Test
method hereinbefore described and it was determined that the primed
PC lenses coated with the coating compositions prepared employing
the procedures set forth in this example had a Bayer number of
about 5.4.
[0094] The following examples 10A -12 E illustrate process
variations which can be employed in the formulation of the
compositions of the present invention having improved
abrasion-resistance.
Example 10A
[0095] 116.0 grams of 3-glycidoxypropyltrimethoxysilane, 255.3
grams of tetraethyl orthosilicate, 17.4 grams of itaconic acid and
191.8 grams of propylene glycol methyl ether were combined while
being stirred into a single mix. 191.8 grams of water were added to
make a resulting mixture. The mixture was then stirred for 17 hours
to produce a coating composition.
[0096] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 2.1 microns. The coated lenses were then
subjected to the modified Oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating composition prepared employing the procedures set
forth in this Example had a Bayer number of about 7.5.
Example 10B
[0097] 0.9 grams of benzyldimethylamine were added to 380 grams of
the coating composition of Example 10A and stirred for about 6
hours.
[0098] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 2.1 microns. The coated lenses were then
subjected to the modified oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating composition prepared employing the procedures set
forth in this Example had a Bayer number of about 10.7.
Example 11
[0099] 45.4 grams of itaconic acid, 723.1 grams of propylene glycol
methyl ether were combined with stirring to form a resulting
mixture. 375.4 grams of deionized water were then added to form an
aqueous-organic solvent admixture. 726.1 grams of tetraethyl
orthosilicate were added to the admixture and stirred 24 hours.
329.6 grams of 3-glycidoxypropyltrimethoxysilane were then added to
produce a coating composition.
[0100] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 1.5 microns. The coated lenses were then
subjected to the modified oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating composition prepared employing the procedures set
forth in this Example had a Bayer number of about 7.4.
Example 12A
[0101] A) 188.9 grams of tetraethyl orthosilicate were added to a
mixture of 212 grams of deionized water, 86.7 grams of propylene
glycol methyl ether and 11.8 grams of itaconic acid and the
resulting mixture was stirred for 18 hours and stored at 5.degree.
C.
[0102] B) 476.8 grams of 3-glycidoxypropyltrimethoxysilane were
added to 273.7 grams of deionized water and the resulting mixture
was stirred for 18 hours and stored at 5.degree. C.
[0103] C) 67.4 grams of the mixture produced in step B above were
added to 250 grams of mixture produced in step A above to produce a
coating composition. The coating composition was stirred for 24
hours.
[0104] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 1.3 micron. The coated lenses were then
subjected to the modified Oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating composition prepared employing the procedures set
forth in this Example had a Bayer number of about 9.3.
Example 12B
[0105] 10.34 ml of an aqueous 0.105 molar sodium hydroxide solution
were added to 250 grams of mixture A from Example 12A above to a
final pH of 3.4. The mixture was stirred for 18 hours. 67.4 grams
of mixture B (Example 12A) were then added to this mixture to
produce an admixture. The admixture was stirred for 24 hours. A
163.9 gram aliquot of the admixture was then diluted with 37.3
grams of propylene glycol methyl ether to produce a coating
composition.
[0106] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 2.4 microns. The coated lenses were then
subjected to the modified Oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating composition prepared employing the procedures set
forth in this Example had a Bayer number of about 13.9.
Example 12C
[0107] 1312.1 grams of tetraethyl orthosilicate were added to a
mixture of 82.1 grams of itaconic acid, 639.1 grams of water, and
1005 grams of propylene glycol methyl ether to make an
aqueous-organic solvent mixture. This mixture was stirred for 18
hours. 115.4 grams of mixture B in example 12A above were added to
364.6 grams of the aqueous-organic solvent mixture. The mixture was
stirred for 18 hours to produce a coating composition.
[0108] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating. The coated
lenses were then subjected to the modified Oscillating Sand Test
method hereinbefore described and it was determined that the etched
ADC lenses coated with the coating composition prepared employing
the procedures set forth in this Example had a Bayer number of
about 8.7.
Example 12D
[0109] Benzyldimethylamine was added dropwise to the coating
composition described in Example 12C to yield a coating composition
with a pH value of 4.2.
[0110] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 1.8 microns. The coated lenses were then
subjected to the modified Oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating composition prepared employing the procedures set
forth in this Example had a Bayer number of about 10.1.
Example 12E
[0111] 1 molar aqueous sodium hydroxide solution was added dropwise
to the coating composition described in Example 12C to yield a
coating composition with a pH value of 3.6.
[0112] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 1.7 microns. The coated lenses were then
subjected to the modified Oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating composition prepared employing the procedures set
forth in this Example had a Bayer number of about 10.3.
[0113] Examples 12D -12E illustrate the use of a catalyst with the
fully formulated coating of Example 12C.
Example 13
[0114] Following the procedure described in Example 1, 61.4 grams
of 3-glycidoxypropyltrimethoxysilane, 96.4 grams of water, 88.7
grams of propylene glycol methyl ether, 9.2 grams of itaconic acid
and 128.3 grams of tetraethyl orthosilicate were combined in an
admixture. To this admixture, 13 grams of Nalco 1115 colloidal
silica were added by pouring and stirred overnight to produce a
coating composition.
[0115] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 1.9 microns. The coated lenses were then
subjected to the modified Oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating composition prepared employing the procedures set
forth in this Example had a Bayer number of about 9.8.
Example 14
[0116] Following the procedure described in Example 1, 61.9 grams
of 3-glycidoxypropyltrimethoxysilane, 87.2 grams of water, 87.1
grams of propylene glycol methyl ether, 9.3 grams of itaconic acid
and 116.1 grams of tetraethyl orthosilicate were combined in an
admixture. To this admixture, 38.7 grams of Nalco 1115 colloidal
silica were added by pouring and stirred overnight to produce a
coating composition.
[0117] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 2.0 microns. The coated lenses were then
subjected to the modified Oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating composition prepared employing the procedures set
forth in this Example had a Bayer number of about 12.6.
Example 15
[0118] Following the procedure outlined in Example 1, 61.2 grams of
3-glycidoxypropyltrimethoxysilane, 75.8 grams of water, 83.7 grams
of propylene glycol methyl ether, 9.2 grams of itaconic acid and
101 grams of tetraethyl orthosilicate were combined in an
admixture. To this admixture, 64.7 grams of Nalco 1115 colloidal
silica were added by pouring and stirred overnight to produce a
coating composition.
[0119] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 2.1 microns. The coated lenses were then
subjected to the modified Oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating composition prepared employing the procedures set
forth in this Example had a Bayer number of about 11.
Example 16
[0120] 17.4 grams of itaconic acid, 106 grams of water and 225.9
grams of propylene glycol methyl ether were combined to form a
mixture. 223.3 grams of tetraethyl orthosilicate were added
dropwise to the mixture while stirring to produce a first
admixture. The first admixture was then stirred for approximately
two hours. 61.4 grams of Nalco 1115 colloidal silica were rapidly
added by pouring to produce a second admixture. The second
admixture was then stirred for about 15 minutes and 116 grams of
3-glycidoxypropyltrimethoxysilane were added dropwise to provide a
resulting third admixture which was stirred approximately 14 hours.
0.06 grams of a silicone leveling agent (PA-57) in 0.5 grams of
propylene glycol methyl ether were added to produce a coating
composition.
[0121] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating. The coated
lenses were then subjected to the modified Oscillating Sand Test
method hereinbefore described and it was determined that the etched
ADC lenses coated with the coating composition prepared employing
the procedures set forth in this Example had a Bayer number of
about 11.6.
Example 17
[0122] 153.1 grams of 3-glycidoxypropyltrimethoxysilane were added
slowly to 181.1 grams of Nalco 1115 colloidal silica, 100.5 grams
of water and 5 grams of itaconic acid which were being stirred
constantly. The aqueous 3-glycidoxypropyltrimethoxysilane mixture
was then stirred for one hour. 324.4 grams of propylene glycol
methyl ether and an additional 16 grams of itaconic acid were
added. 220 grams of tetraethyl orthosilicate were then added to the
mixture, followed by another 50 grams of propylene glycol methyl
ether and then stirred overnight to produce a coating
composition.
[0123] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 2.4 microns. The coated lenses were then
subjected to the modified oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating composition prepared employing the procedures set
forth in this Example had a Bayer number of about 13.6.
Example 18
[0124] 153.1 grams of 3-glycidoxypropyltrimethoxysilane were added
slowly to a mixture of 90.5 grams of Ludox HS-30 colloidal silica,
(DuPont Company, Wilmington, Del.) 190 grams of water and 5 grams
of itaconic acid which was being constantly stirred. The
3-glycidoxypropyltrimethoxys- ilane mixture was then stirred for
approximately two hours. 325.4 grams of propylene glycol methyl
ether and an additional 16 grams of itaconic acid were then added
to the 3-glycidoxypropyltrimethoxy-silane mixture and stirred for
an additional hour to produce an admixture. 110 grams of tetraethyl
orthosilicate were slowly added to a 390 gram aliquot of the
admixture while the admixture was being constantly stirred. The
resulting mixture was stirred overnight to produce a coating
composition.
[0125] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 2.4 microns. The coated lenses were then
subjected to the modified Oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating composition prepared employing the procedures set
forth in this Example had a Bayer number of about 8.4.
Example 19
[0126] 132.0 grams of tetraethyl orthosilicate were added to a
solution of 12.6 grams of itaconic acid in a mixture of 114.0 grams
of isopropanol and 114 grams deionized water. The mixture was
stirred for 3 hours. 54.3 grams of Ludox HS-30 colloidal silica
were added followed by an additional 80 grams of isopropanol. 91.8
grams of 3-glycidoxypropyltrimet- hoxysilane were then added to
this mixture and stirred for about 18 hours. 75 ppm of a silicon
leveling agent (PA-57) were added to produce a coating
composition.
[0127] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 3.0 microns. The coated lenses were then
subjected to the modified Oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating composition prepared employing the procedures set
forth in this Example had a Bayer number of about 7.9.
[0128] Examples 13-19 illustrate the addition of colloidal silica
to the compositions of the present invention formulated from an
epoxy functional silane, a tetrafunctional silane and a
multifunctional compound to produce compositions which, upon
curing, have improved abrasive resistance properties.
[0129] Examples 16-19 also illustrate the optional use of two
different types of basic colloidal silica and possible variations
in mixing sequences.
Example 20
[0130] 18.9 grams of methyltrimethoxysilane were added slowly to
56.3 grams of water which was being constantly stirred. 19.8 grams
of 3-glycidoxypropyltrimethoxysilane were then added slowly to this
solution and stirred approximately one hour. 4.5 grams of itaconic
acid pre-dissolved in 56.3 grams of propylene glycol methyl ether
were added to the mixture and stirred for an additional hour. 81.3
grams of tetraethyl orthosilicate were slowly added, stirred an
additional two hours and the mixture then allowed to sit at ambient
temperature overnight. 1.4 grams of benzyldimethylamine were then
added to the resultant product to produce a coating
composition.
[0131] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 3.4 microns. The coated lenses were then
subjected to the modified Oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating composition prepared employing the procedures set
forth in this Example had a Bayer number of about 10.8.
[0132] Example 20 illustrates the addition of a silane to the
compositions of the present invention formulated from an epoxy
functional silane, a tetrafunctional silane, and a multifunctional
compound.
Example 21
[0133] 18.9 grams of methyltrimethoxysilane were added slowly to
33.5 grams of Nalco 1042 colloidal silica which was being
constantly stirred. 19.8 grams of 3-glycidoxypropyltrimethoxysilane
were then added slowly to this solution and stirred approximately
one hour. 4.5 grams of itaconic acid pre-dissolved in 56.3 grams of
propylene glycol methyl ether were added to the mixture. This
mixture was allowed to stir for an additional hour before slowly
adding 40.7 grams of tetraethyl orthosilicate to produce an
admixture which was stirred an additional two hours and then
allowed to sit at ambient temperature overnight. 1.4 grams of
benzyldimethylamine were added to the admixture to produce a
coating composition.
[0134] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 3.3 microns. The coated lenses were then
subjected to the modified oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating composition prepared employing the procedures set
forth in this Example had a Bayer number of about 6.6.
Example 22
[0135] Following the procedure outlined in Example 21, 16.8 grams
of Nalco 1042 colloidal silica, 18.9 grams of
methyltrimethoxysilane, 19.8 grams of
3-glycidoxypropyltrimethoxysilane, 4.5 grams of itaconic acid, 56.3
grams of propylene glycol methyl ether, 61.0 grams of tetraethyl
orthosilicate and 1.4 grams of benzyldimethylamine were combined to
produce a coating composition.
[0136] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 3.1 microns. The coated lenses were then
subjected to the modified oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating composition prepared employing the procedures set
forth in this Example had a Bayer number of about 9.9.
Example 23
[0137] 37.7 grams of 3-glycidoxypropyltrimethoxysilane were added
slowly to 82.1 grams of water which was constantly stirred. The
aqueous 3-glycidoxypropyltrimethoxysilane mixture was then stirred
for approximately one hour. 5.2 grams of itaconic acid predissolved
in 96.6 grams of propylene methyl glycol ether were added to the
mixture. The solution was then stirred for an additional two hours
before adding 0.54 grams of dimethyldimethoxysilane. This mixture
was then stirred for 30 minutes and 77.4 grams of tetraethyl
orthosilicate were added to the mixture to produce an admixture,
then stirred an additional two hours and allowed to sit at ambient
temperature overnight. 0.6 grams of benzyldimethylamine were added
to the admixture to produce a coating composition.
[0138] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 3.1 microns. The coated lenses were then
subjected to the modified Oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating composition prepared employing the procedures set
forth in this Example had a Bayer number of about 11.5.
Example 24
[0139] Following the procedure outlined in Example 23, 37.7 grams
of 3-glycidoxrpropyltrimethoxysilane, 82.1 grams of water, 5.2
grams of Itaconic acid, 96.6 grams of propylene glycol methyl
ether, 2.7 grams of dimethyldimethoxysilane, 77.4 grams of
tetraethyl orthosilicate and 0.6 grams of benzyldimethylamine were
combined to produce a coating composition.
[0140] The coating composition was applied to the etched ADC lenses
according to Procedure A to provide a cured coating having a
thickness of about 2.6 microns. The coated lenses were then
subjected to the modified Oscillating Sand Test method hereinbefore
described and it was determined that the etched ADC lenses coated
with the coating composition prepared employing the procedures set
forth in this Example had a Bayer number of about 8.6.
[0141] Changes may be made in the construction and the operation of
the various components, elements and assemblies described herein
and changes may be made in the steps or the sequence of steps of
the methods described herein without departing from the spirit and
scope of the invention as defined in the following claims.
* * * * *