Coating processes – With post-treatment of coating or coating material – Heating or drying
Reexamination Certificate
2000-06-27
2002-06-11
Dawson, Robert (Department: 1712)
Coating processes
With post-treatment of coating or coating material
Heating or drying
C427S136000, C106S002000, C106S287140, C106S287160, C524S588000, C524S837000
Reexamination Certificate
active
06403163
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
REFERENCE TO A MICROFICHE APPENDIX
Not applicable.
FIELD OF THE INVENTION
This invention is directed to organosilicon compositions which are useful as water repellents for application to the surface of mineral substrates used in the construction industry. Representative mineral substrates are building materials such as brick, cured concrete, sewer pipe, hollow block, cured mortar, stucco, decorative stone, roofing tile, and structures which incorporate such building materials, i.e., highway surfaces, bridges, concrete, stone or brick building exteriors, footings, and retaining walls.
The organosilicon compositions can also be used in the preparation of castable or trowelable mineral compositions such as uncured cement; as compositions for use on wood substrates, particularly compositions for exterior residential wood decks; in the manufacture of gypsum wall board whether incorporated into uncured formulations or applied to the surface of gypsum wall boards; and in the manufacture of inorganic granules for roofing shingles.
BACKGROUND OF THE INVENTION
While U.S. Pat. No. 5,074,912 (Dec. 24, 1991) and U.S. Pat. No. 5,919,296 (Jul. 6, 1999) each relate to the use of a polymethylhydrogensiloxane in the treatment of masonry, neither patent teaches the use of a combination of components including a polymethylhydrogensiloxane, an alkoxysilane, and a silicone resin.
Further, while U.S. Pat. No. 5,300,327 (Apr. 5, 1994) and U.S. Pat. No. 5,695,551 (Dec. 9, 1997) each relate to the use of an alkoxysilane and a silicone resin in the treatment of masonry, neither patent teaches the use of a combination of components including a polymethylhydrogensiloxane, an alkoxysilane, and a silicone resin.
In addition, none of these patent suggest that compositions used for treating masonry which include such a combination of components can also include either a volatile methyl siloxane or a cationic oil-in-water emulsion of an aminofunctional polydimethylsiloxane.
Thus, compositions according to this invention differ from what is known in the prior art in that the compositions contain a unique combination of components, i.e., the polymethylhydrogensiloxane, alkoxysilane, and silicone resin, which compositions may also further include either a volatile methyl siloxane or a cationic oil-in-water emulsion of an aminofunctional polydimethylsiloxane.
BRIEF SUMMARY OF THE INVENTION
This invention relates to low VOC penetrating water repellent compositions for use on inorganic building materials, including the emulsification and delivery of certain reactive silicon-based materials for improving the water repellency performance on substrates of inorganic building material. In particular, the invention is directed to compositions containing polymethyhydrogensiloxanes, alkoxysilanes, and silicone resins. VOC exempt silicone solvents can be included in these compositions for providing water repellency on inorganic building materials. In addition, other types of additives may be incorporated into these compositions in order to develop water repellency on such substrates in a reduced time frame. Such additives typically are selected so as to provide increased beading and/or increased water repellency performance.
In terms of their function in such compositions, the polymethyhydrogensiloxane excludes water; the alkoxysilane reduces darkening; and the silicone resin increases the ability of treated surface to exclude water under conditions involving the application of hydrostatic pressure, i.e., wind driven rain or high pressure application of water.
These and other features of the invention will become apparent from a consideration of the detailed description.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
Not applicable.
DETAILED DESCRIPTION OF THE INVENTION
Compositions according to this invention comprise a combination of components including a polymethylhydrogensiloxane, an alkoxysilane, and silicone resin. These compositions may also include other components such as a cationic oil-in-water emulsion of an aminofunctional polydimethylsiloxane, a volatile methyl siloxane, and mixtures thereof, for example.
The Polymethylhydrogensiloxane
Suitable polymethylhydrogensiloxanes for use in this invention include compositions having the formula
where R1 to R8 represent hydrogen or an alkyl group containing 1-6 carbon atoms, with the proviso that at least one of the groups R1 to R8 is hydrogen. In the formula, x is an integer of from 1 to about 200. Most preferred are compositions in which about one half of the groups R1 to R8 in the polymethylhydrogensiloxane are hydrogen; while the remainder of the groups are methyl groups.
One representative example of a polymethylhydrogensiloxane especially preferred for use herein is a trimethylsiloxy terminated polymethylhydrogensiloxane with a silicon-bonded hydrogen content of 1.4 to 1.75 weight percent, and having a viscosity between 20 to 40 centistoke (mm
2
/sec.).
Polymethylhydrogensiloxane copolymers can also be used, and suitable copolymers include (alkylmethyl)(methylhydrogen)siloxane copolymers having the formula
where the groups R9 to R18, except the groups R16 and R17, each represent an alkyl group containing 1-6 carbon atoms, typically a methyl group, R16 represents hydrogen, and R17 represents an higher alkyl group containing more than about six carbon atoms. The values of y and z can be from 1 to about 200.
Such polymethylhydrogensiloxane polymers and copolymers are commercially available from the Dow Corning Corporation, Midland, Mich., and are described, for example, in U.S. Pat. No. 5,074,912 (Dec. 24, 1991) and U.S. Pat. No. 5,919,296 (Jul. 6, 1999).
The Alkoxysilane
The alkoxysilane can constitute a single alkoxysilane or a mixture of alkoxysilanes can be employed. The alkoxysilane has the formula R
a
Si(OR′)
4−a
. In the formula, R represents an alkyl group having 1-10 carbon atoms, preferably 1-8 carbon atoms, an alkenyl group having 2-8 carbon atoms, an aryl group such as phenyl, or an haloalkyl group such as chloropropyl and trifluoropropyl. The value of a is 1 or 2, and R′ represents an alkyl group having 1-6 carbon atoms. Preferably, R is methyl, isobutyl, or n-octyl, and R′ is methyl or ethyl.
Some suitable alkoxysilanes are methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, ethyltributoxysilane, propyltrimethoxysilane, propyltriethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, butyltriethoxysilane, hexyltrimethoxysilane, n-octyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diisobutyldimethoxysilane, phenyltrimethoxysilane, dibutyldiethoxysilane, and dihexyldimethoxysilane.
Such alkoxysilanes are commercially available from the Dow Corning Corporation, Midland, Mich., and are described, for example, in U.S. Pat. No. 5,300,327 (Apr. 5, 1994), U.S. Pat. No. 5,695,551 (Dec. 9, 1997), and U.S. Pat. No. 5,919,296 (Jul. 6, 1999).
The Silicone Resin
The silicone resin can be any one of the various types of resinous copolymers described in detail in U.S. Pat. No. 5,695,551 (Dec. 9, 1999). However, most preferred for use herein are those resinous copolymers described as:
I. A resinous copolymeric siloxane prepared by a method comprising (i) forming an acidic homogenous mixture of a silanol containing resinous copolymeric siloxane with R″
3
SiO
1/2
units and SiO
4/2
units; an organohydrogen polysiloxane with the formula R″
b
H
c
SiO
(4−b−c)/2
where b and c are positive integers with a sum less than four, preferably 1.9-2.1; and an organic solvent, and (ii) heating the mixture to remove substantially all organic solvent. R″ can be an alkyl group with 1-6 carbon atoms; an aryl group such as phenyl, tolyl, and xylyl; an alkenyl group such as vinyl and allyl; or a trifluoropropyl group. R″ can also be an arylalkyl group such as betaphenylethyl and betaphenylpropy
Fisher Paul David
Lin Feifei
Stark-Kasley Lori Ann
ChemRex Inc.
Dawson Robert
Renner Kenner Greive Bobak Taylor & Weber
Robertson Jeffrey B.
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