Stock material or miscellaneous articles – Composite – Of silicon containing
Reexamination Certificate
2000-05-02
2002-06-11
Moore, Margaret G. (Department: 1712)
Stock material or miscellaneous articles
Composite
Of silicon containing
C556S413000, C556S425000, C556S458000, C528S027000, C528S038000, C549S215000, C106S287110
Reexamination Certificate
active
06403227
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to coating compositions and, more particularly, to polyorganosiloxane compositions that can form mar resistant coatings and coatings made from these compositions.
2. Background of the Art
A variety of substrates, including those made of glass, plastic, metal, or masonry, are usefully coated with protective films to reduce their tendency to be abraded, to provide sacrificial surfaces, and to resist corrosion. It is generally desirable that protective coatings have good weathering and adhesion. It is also desirable that such coatings be resistant to thermal shock, mechanical shock, heat, humidity, and common chemicals. In addition, the coatings must be practical to prepare, apply, dry, and cure.
Some plastics are desirable substitutes for glass due to lighter weight, economically advantageous fabrications, and breakage resistance. However, commercially available plastic surfaces are less abrasion resistant, mar resistant, and scratch resistant than glass. Thus, protective coatings for plastic substrates are of particular interest. This is particularly true within the field of optical uses for plastic materials (e.g., as lenses, windows, covers, containers, ophthalmic layers, and the like) where damage to the surface of the polymer can significantly affect its function.
Much effort has been exerted in this field, and several different technical approaches have been described. In particular, work has been carried out on the development of polyorganosiloxanes crosslinked by the condensation of silanol groups.
Mayazumi, in U.S. Pat. No. 3,837,876, describes a polymer formed by reacting an aminosilane with an epoxysilane, dissolving the resulting product in a solvent, and then coating various substrates with the solution of the product. Ender, in U.S. Pat. No. 3,166,527, describes the mixing of an epoxysilane with an aminosilane, then coating surfaces with both the unreacted mixture and the reacted (partially polymerized) mixture. The coating was cured by standing at room temperature for a longer period of time or by heating for a shorter period of time.
Koda, in U.S. Pat. No. 3,961,977, describes the use of a partially hydrolyzed (10-40%) aminoalkoxysilane and an epoxysilane in a coating mixture. The two are dissolved in a solvent that may include a ketone. The ketone, although not claimed as a blocking agent to polymerization, appears to impede polymerization, thus extending the pot life.
Treadway and Carr, in U.S. Pat. No. 4,378,250, describe the use of aldehydes or ketones as blocking agents in polymeric compositions derived from certain aminosilanes and epoxysilanes. The reference also describes the nuance of increasing the hydrolysis of the silanes to above 40%. The reference describes greater abrasion resistance in the cured product and longer pot life in the curable composition because of the presence of the ketone acting to retard the reaction between the amine functionality and the epoxy functionality on the various reactants. The use of two different silanes make the formulation of the coating ponderous and, furthermore, there is a limited dye tintability range that can be obtained by varying the ratio of epoxy to amino within the bounds of compositions described for attaining the desired level of abrasion resistance. Replication of these compositions shows crosslink equivalent weights of at least about 173 when fully cured.
Copending U.S. patent application Ser. No. 09/010,731 filed on Jan. 22, 2000, now U.S. Pat. No. 6,057,040, relates to an improved coating comprising a coating on a substrate is described. The coating comprises a crosslinked polymeric material derived from an alkine-bridged bis-(aminosilane) or comprising a mixture of the alkine-bridged bis-(amino-silane) and an epoxysilane. The alkine bridged bis-(aminosilane) may have the general formula:
[R
1
OR
2
OR
3
O—Si—(CH
2
)
n
-NH]
p
—(CH
4-p
)
q
(CH
2
)
m
(CH
3
)
o,
[R
1
OR
2
OR
3
O—Si—(CH
2
)
n
-NH]
2
—(C
m
H
2m
)
or
wherein
R
1
, R
2
, and R
3
are independently selected from alkyl groups of 1 to 4 carbon atoms or phenyl groups,
R
4
is selected from hydrogen, phenyl groups, and alkyl of from 1 to 4 carbon atoms, and
n is 1, 2, 3 or 4,
p is 2, 3 or 4,
q is 0 or 1,
o is 0 or 1, and
m is 1, 2, 3 or 4,
wherein q plus m is 1 or 2, o is 1 only when all aminosilane groups are bonded to the other alkine groups, and when p is 4, both m and o are zero, or preferably
[R
1
OR
2
OR
3
O—Si—(CH
2
)
n
-NH]
2
—(C
m
H
2m
)
wherein
R
1
, R
2
, and R
3
are independently selected from aliphatic groups or aromatic groups, and
n is 1, 2, 3 or 4, and
m is 1, 2, 3 or 4.
The alkine bridged bis-(aminosilane) is itself a novel compound. A novel coating composition comprises a coating composition comprising a solution comprising and epoxysilane and an alkine-bridged bis-(amino-silane), especially where the alkine-bridged bis-(amino-silane) has the general formula:
[R
1
OR
2
OR
3
O—Si—(CH
2
)
n
-NH]
2
—(C
m
H
2m
)
wherein
R
1
, R
2
, and R
3
are independently selected from aliphatic groups or aromatic groups which complete a silane, and
n is 1, 2, 3 or 4, and
m is 1, 2, 3 or 4.
SUMMARY OF THE INVENTION
The present invention relates to a novel bis-aminosilane, coating compositions containing the bis-aminosilane, coatings made from those coating compositions, and articles having the cured coating compositions on at least one surface thereof. The coating compositions comprise at least the crosslinked product of the bis-aminosilane and preferably at least two polymerizable compounds (one of which is the bis-aminosilane of the present invention). These compositions may form a crosslinked polymeric coating. At least one of the polymerizable compounds comprises an alkine-bridged bis-(aminesilane) and another preferred polymerizable compound in the composition comprises an epoxy-functional silane. The coatings provided from these compositions are highly crosslinked and display excellent mar resistance, as well as increased tintability, a very unusual combination. It is common in the art that where one of these properties increases, it is done at the expense of the other property.
DETAILED DESCRIPTION OF THE INVENTION
Abrasion resistant coating technology and solvent resistant coating technology often tend to overlap in the range of useful chemistries, and the technologies are used in a wide range of commercial products. In general, polymeric surfaces tend to require protection against abrasion and solvent attack, but soft metal surfaces and composite surfaces may likewise need protection. Additionally, even a single substrate composition may require different quality or different types of resistance, depending on the environment into which the surface is being placed. It is therefore desirable to provide the widest range of compositions to allow selection for use among the various fields or environments of use to which vulnerable surfaces are introduced.
A starting monomer or comonomer for use in the practice of the present invention comprises a tetrahydrocarbyl-aminosilane in which a central carbon atom has all four valences bonded to an amino silane group that can be subsequently polymerized to form a tightly packed, crosslinked hard coat or abrasion resistant coating, particularly for polymeric surfaces such as ophthalmic lenses. The starting compound for the polymer may be represented by the formula:
wherein the amino-silane groups may have different R groups within each aminosilane group and between each aminosilane group, as where each aminosilane group comprises
wherein the R
1
, R
2
, and R
3
group of each of R
1
O, R
2
O and R
3
O may be the same or different amongst each of the aminosilane groups. The term tetrahydrocarbyl indicates that all four valences of the bridging carbon atom have been substituted with the described aminosilane functionality. R
4
is selected from hydrogen, phenyl groups, and alkyl of from 1 to 4 carbon atoms.
The term alkine group or alkylene group is used to describe an
Mark A. Litman & Assoc. P.A.
Moore Margaret G.
Peng Kuo-Liang
Vision-Ease Lens. Inc.
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