Stock material or miscellaneous articles – Composite – Of silicon containing
Reexamination Certificate
2001-06-18
2003-10-21
Dawson, Robert (Department: 1712)
Stock material or miscellaneous articles
Composite
Of silicon containing
C428S447000, C428S412000, C528S020000, C528S031000, C528S038000, C528S042000
Reexamination Certificate
active
06635353
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to novel polymers, polymers used in coating compositions and, more particularly, to polyorganosiloxane compositions that can form mar resistant coatings and coated articles 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 their lower density, 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%) aminosilane 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 required method of preparation to make the coating is 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.
U.S. Pat. No. 6,057,040 describes a alkine bridged bis-aminosilanes, coating compositions containing these bis-aminosilanes, coatings made from those coating compositions, and articles having the cured coating compositions on at least one surface thereof. These compositions may form a crosslinked polymeric coating. At least one of the polymerizable compounds comprises an alkine-bridged bis-(aminosilane) 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.
SUMMARY OF THE INVENTION
A polymer comprising an alkylamine-bridged polysilane provides a wide range of unique properties that can be effectively used in many technologies, but especially in the provision of abrasion resistant coatings, and especially abrasion resistant coatings on polymeric surfaces. The product is highly crosslinked, has excellent adherence to various surfaces without the need for adhesives, and inherently provides significant antistatic protection without the need for antistatic additives. Certain alkylamine-bridged polysilanes have as many as six crosslinking bridges. The polymers can be made without catalysts using low cost monomers. The product may be derived by reaction of a halogenated hydrocarbyl substituted tri-oxyfunctional silane and an alkylamino silane. The polymer may be made by admixing a haloalkyltrialkoxysilane and an aminoalkyltrialkoxysilane in a solvent in the presence of water.
DETAILED DESCRIPTION OF THE INVENTION
The polysiloxanes described in the invention may be generally represented as a polymer having at least one repeating unit of the formulae:
or
or the corresponding hydrogen halide salts or ammonium hydrogen halide salts (e.g., hydrogen chloride, hydrogen bromide, hydrogen iodide, hydrogen fluoride salts, leaving the halide ion as a counterion on the molecule).
These formulae are not necessarily exclusive, but may in fact describe the same polymer as shown below. Preferably at least three of the (e.g., shown) six —O—groups on the silicon atoms are bonded to other polymeric units (with the at least three bonds to other polymeric units thereby forming a crosslinked polymer unit). When the —O—groups are not bonded to other polymeric units they are independently bonded to hydrogen, alkyl groups (e.g., of from 1 to 6 or 1 to 4 carbon atoms, especially 1 or 2 carbon atoms) and phenyl groups, and more preferably unsubstituted alkyl groups;
n and m are independently selected from 1 to 6, but as high as 10 is possible and in some cases may be desirable,
R
13
is selected from H, alkyl group of from 1 to 4 carbon atoms (preferably 1 or 2 carbon atoms), benzyl, and phenyl groups;
R
14
and R
15
are independently selected from alkyl groups (preferably of from 1 to 6 carbon atoms, but longer alkyl groups, e.g., to 10 carbon atoms are possible and could add some additional flexibility), xylylene, and phenylene groups.
Other groups may be present in the polymer, but the above-identified novel groups must be present in the practice of the present invention. The above formulae are also contemplated to cover, and in some situations are preferably directed to ionic species where the nitrogen atom of the amine has accepted a proton, and has a counter ion. In the preferred production or synthesis process for the polymers, halogen terminated reactants are used, halogen acids (e.g., HI, HBr, HCl, and HF) may be formed, and this will inherently provide the ammonium salts. The counter ions may be replaced to form alternative ammonium salts, where such alternative counter ions could provide other unique benefits (e.g., reduce or increase color or tint of the composition). Some possible alternative counter ions include but are not limited to sulfate, sulfite, nitrate, nitrite, phosphate, and phosphite.
Haloalkyltrialkoxysilanes and Aminoalkyltrialkoxysilanes
Haloalkyltrialkoxysilanes include compounds of the formulae:
wherein R
1
, R
2
, and R
3
are independently hydrogen, monovalent hydrocarbon radicals (e.g., benzyl, phenyl groups, alkyl and other aliphatic radicals, especially alkyl groups, and most particularly methyl and ethyl);
R
4
is selected from hydrogen, aliphatic groups, benzyl, and phenyl groups, alkyl of from 1 to 20 carbon atoms or especially alkyl groups of from 1 to 4 carbon atoms;
X is a halogen such as Cl,
Dawson Robert
Feely Michael J
Mark A. Litman & Associates P.A.
Vision--Ease Lens, Inc.
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