Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2002-01-04
2003-12-16
Wu, David W. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S502000, C524S522000, C524S080000, C524S081000, C526S072000, C526S089000, C427S393000
Reexamination Certificate
active
06664327
ABSTRACT:
This invention relates to an aqueous composition. In particular, this invention relates to an aqueous composition including polymers containing hydrophobic monomers as polymerized units which is useful as a stain for wood. Further, this invention relates to a method of using the aqueous composition.
Wood is used extensively in the construction of decks, fences, and other exterior structures. To protect the wood from moisture and sunlight, the wood is often treated with a stain or sealer which reduces the penetration of moisture into the wood. The stain or sealer provides protection to the wood by sealing the wood pores on the surface of the wood and by minimizing wetting of the wood surface. The formation of water drops on the surface of the treated wood, commonly referred to as “beading”, indicates resistance to water wetting and penetration into the wood. Besides providing protection to the wood, a stain or sealer may be applied to improve the appearance of the wood. Pigmented stains, commonly referred to as “semi-transparent” stains may be used to provide a desired color to the wood. Stains and sealers are often re-applied to wood on time intervals of a year or longer.
U.S. Pat. No. 6,040,409 discloses a composition containing a hydrophobic polymer which includes hydrophobic monomers as polymerized groups, a second polymer, and water. The hydrophobic polymer is useful in floor polish compositions as a wax replacement. The composition containing the hydrophobic polymer monomer composition, which optionally may include wax, provides a clear floor polish with improved repair properties and a less slippery walking surface. It is further disclosed that the composition may also be used in architectural and industrial coatings including wood coatings.
Despite the disclosure of the prior art, there is a need for stains and sealers for wood with improved water beading. Stains and sealers with improved water beading may provide improved resistance to the penetration of moisture or provide longer time intervals before the re-application of the stain or sealer. The inventors have found that compositions containing hydrophobic polymer and wax provide water beading to wood, particularly for longer periods of time than conventional stains and sealers.
The first aspect of this invention provides an aqueous composition containing: from 2 to 25 weight % first polymer, based on weight of the aqueous composition, wherein the first polymer includes as polymerized units from 20 to 100 weight % of at least one C
12
to C
40
alkyl ester of (meth)acrylic acid, based on weight of the first polymer, from 0 to 10 weight % of at least one ethylenically unsaturated acid or amide containing monomer or salts thereof, based on weight of the first polymer; and from 0 to 80 weight % of at least one ethylenically unsaturated monomer, based on weight of the first polymer; from 0.1 to 5 weight % of at least one wax, based on weight of the aqueous composition; from 1 to 20 weight % of at least one pigment, based on weight of the aqueous composition; and from 0 to 32 weight % of at least one second polymer, based on weight of the aqueous composition; wherein the sum of the first polymer and the second polymer is at least 10 weight %, based on weight of the aqueous composition; wherein the weight ratio of the first polymer to the second polymer is at least 1:4; and wherein the first polymer and the second polymer have a combined glass transition temperature in the range of −5 to 20° C.
The second aspect of this invention provides a method of treating a wood surface including the steps of preparing an aqueous composition containing: from 2 to 25 weight % first polymer, based on weight of the aqueous composition, wherein the first polymer includes as polymerized units from 20 to 100 weight % of at least one C
12
to C
40
alkyl ester of (meth)acrylic acid, based on weight of the first polymer, from 0 to 10 weight % of at least one ethylenically unsaturated acid or amide containing monomer or salts thereof, based on weight of the first polymer, and from 0 to 80 weight % of at least one ethylenically unsaturated monomer, based on weight of the first polymer; from 0.1 to 5 weight % of at least one wax, based on weight of the aqueous composition; from 1 to 20 weight % of at least one pigment, based on weight of the aqueous composition; and from 0 to 32 weight % of at least one second polymer, based on weight of the aqueous composition; wherein the sum of the first polymer and the second polymer is at least 10 weight %, based on weight of the aqueous composition; wherein the weight ratio of the first polymer to the second polymer is at least 1:4; and wherein the first polymer and the second polymer have a combined glass transition temperature in the range of −5 to 20° C.; applying the aqueous composition onto the wood surface; and drying or allowing to dry the aqueous composition.
As used herein, the term “(meth)acrylate” refers to either acrylate or methacrylate and the term “(meth)acrylic” refers to either acrylic or methacrylic. As used herein, the term “hydrophobic monomer” refers to a C
12
to C
40
alkyl ester of (meth)acrylic acid.
“Glass transition temperature” or “T
g
” as used herein, means the temperature at or above which a glassy polymer will undergo segmental motion of the polymer chain. The T
g
of the first polymer and the second polymer reported herein are measured by differential scanning calorimetry.
The present invention provides an aqueous composition suitable for use as a wood stain, containing a first polymer, at least one wax, water, at least one pigment, and optionally at least one second polymer.
The first polymer contains as polymerized units from 20 to 100 weight %, preferably from 30 to 100 weight %, and more preferably from 40 to 100 weight % of at least one C
12
to C
40
alkyl ester of (meth)acrylic acid, based on the weight of the first polymer. It is further preferred that the first polymer used in this invention contains as polymerized units from 30 to 96 weight %, more preferably 40 to 93 weight % of at least one C
12
to C
40
alkyl ester of (meth)acrylic acid, based on the weight of the first polymer. It is preferred that the alkyl ester of (meth)acrylic acid is a C
12
to C
40
alkyl ester of (meth)acrylic acid. Suitable alkyl esters of (meth)acrylic acid include lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, and eicosyl (meth)acrylate. Beneficial properties may be obtained by utilizing more than one C
12
to C
40
alkyl ester of (meth)acrylic acid.
The first polymer may further contain as polymerized units from 0 to 10 weight %, preferably 1 to 5 weight %, more preferably 1 to 3 weight %, based on the weight of the first polymer, of ethylenically unsaturated acid or amide containing monomer or salts thereof. Suitable ethylenically unsaturated acid containing monomers include, but are not limited to acrylic acid, methacrylic acid, crotonic acid, phosphoethyl methacrylate, 2-acrylamido-2-methyl-1-propanesulfonic acid, sodium vinyl sulfonate, itaconic acid, fumaric acid, maleic acid, monomethyl itaconate, monomethyl fumarate, monobutyl fumarate, and maleic anhydride. Acrylic acid and methacrylic acid are preferred. Methacrylic acid is more preferred. Suitable ethylenically unsaturated amide containing monomers include, but are not limited (meth)acrylamide and substituted (meth)acrylamides such as diacetone (meth)acrylamide, and mono- and di-alkyl (meth)acrylamides.
The first polymer may also contain as polymerized units from 0 to 80 weight %, preferably from 0 to 50 weight %, and more preferably 1 to 40 weight %, based on the weight of the first polymer, of at least one ethylenically unsaturated monomer wherein the ethylenically unsaturated monomer is not a C
12
to C
40
alkyl ester of (meth)acrylic acid and is not a ethylenically unsaturated acid or amide containing monomer or salts thereof. Suitable ethylenically unsaturated monomers for use in the preparation of the first polymer include, but are not limited to (meth)acry
Daisey, Jr. George Irwin
Lau Willie
Greenblatt Gary D.
Rohm and Haas Company
Sastri Satya B
Wu David W.
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