Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phosphorus-containing reactant
Reexamination Certificate
2002-12-17
2004-03-23
Truong, Duc (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phosphorus-containing reactant
C524S126000, C524S127000, C524S129000
Reexamination Certificate
active
06710161
ABSTRACT:
This invention relates to a polymer composition containing copolymer particles bearing phosphorus acid groups. The copolymer particles are dispersed in an aqueous medium. The polymer composition is substantially-free of water soluble phosphorus acid compounds. A process is provided for preparing the polymer composition from a monomer composition containing phosphorus acid monomer that is substantially-free of inorganic phosphorus acid compounds. Also provided is the monomer composition and a method of applying the polymer composition to a substrate. The polymer composition of this invention is useful for preparing coatings for metal substrates having improved solvent resistance.
Polymers containing phosphorus acid groups are useful in many applications including coatings and adhesives. The phosphorus acid groups provide improved adhesion of the polymer to metal substrates, form crosslinks in the presence of divalent metal ions, and promote adsorption of the polymer to pigment particles such as titanium dioxide to form composite particles. For example, European Patent Application EP 0 221 498 discloses anti-corrosive random copolymers containing surface-active alkylphosphate monomer as polymerized units. The anti-corrosive random copolymers are useful for preparing coatings that protect substrates from corrosion. However, despite this disclosure, there is a continuing need to provide corrosion resistant coatings with improved solvent resistance.
The inventors have found a polymer composition containing copolymer particles bearing phosphorus acid groups and being substantially-free of water soluble phosphorus acid compounds. The polymer composition is suitable for preparing coatings with improved solvent resistance.
In the first aspect of the present invention, there is provided a polymer composition including copolymer particles bearing first phosphorus acid groups dispersed in an aqueous medium, wherein the copolymer particles contain at least one phosphorus acid monomer as polymerized units; and wherein the polymer composition is substantially-free of water soluble phosphorus acid compounds bearing at least one second phosphorus acid group.
In the second aspect of the present invention, there is provided a process for forming a polymer composition including the steps of preparing an aqueous reaction medium comprising at least one phosphorus acid monomer, wherein the aqueous reaction medium is substantially-free of inorganic phosphorus acid compounds; and polymerizing the aqueous reaction medium to provide the polymer composition.
In the third aspect of the present invention, there is provided a monomer composition including at least one phosphorus acid monomer; wherein the monomer composition is substantially-free of inorganic phosphorus acid compounds.
In the fourth aspect of the present invention, a method is provided for applying a polymer composition including the steps of applying a polymer composition onto a substrate; and drying or allowing to dry the polymer composition; wherein the polymer composition contains copolymer particles bearing first phosphorus acid groups dispersed in an aqueous medium, wherein the copolymer particles contain at least one phosphorus acid monomer as polymerized units; and wherein the polymer composition is substantially-free of water soluble phosphorus acid compounds bearing at least one second phosphorus acid group.
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 “phosphorus acid group” refers to a phosphorus oxo acid having a POH moiety in which the hydrogen atom is ionizable. Also included in the term “phosphorus acid group” are salts of the phosphorus oxo acid. In its salt or basic form, the phosphorus acid group has a cation such as a metal ion or an ammonium ion replacing at least one acid proton. Examples of phosphorus acid groups include groups formed from phosphinic acid, phosphonic acid, phosphoric acid, pyrophosphinic acid, pyrophosphoric acid, partial esters thereof, and salts thereof.
“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. Glass transition temperatures of a polymer can be estimated by the Fox equation [
Bulletin of the American Physical Society
1, 3 Page 123 (1956)] as follows:
1
T
g
=
w
1
T
g
(
1
)
+
w
2
T
g
(
2
)
For a copolymer, w
1
and w
2
refer to the weight fraction of the two comonomers, and T
g(1)
and T
g(2)
refer to the glass transition temperatures of the two corresponding homopolymers in degrees Kelvin. For polymers containing three or more monomers, additional terms are added (w
n
/T
g(n)
). The T
g
of a polymer phase can also be calculated by using the appropriate values for the glass transition temperatures of homopolymers, which may be found, for example, in “Polymer Handbook”, edited by J. Brandrup and E. H. Immergut, Interscience Publishers. The values of T
g
reported herein are calculated based on the Fox equation.
The polymer composition of this invention contains copolymer particles bearing phosphorus acid groups pendant to the polymer backbone. These phosphorus acid groups are referred to herein as “first phosphorus acid groups”. The copolymer particles, which are formed from phosphorus acid monomer, are dispersed in an aqueous medium. The copolymer particles are insoluble in the aqueous medium. The polymer composition is further characterized as being substantially-free of water soluble phosphorus acid compounds.
The copolymer particles are addition polymers, which contain as polymerized units, at least one ethylenically unsaturated monomer having a phosphorus acid group, referred to herein as “phosphorus acid monomer” and at least one second ethylenically unsaturated monomer, referred to herein as “comonomer”.
The phosphorus acid monomer contains at least one ethylenic unsaturation and a phosphorus acid group. The phosphorus acid monomer may be in the acid form or as a salt of the phosphorus acid group. Examples of phosphorus acid monomers include:
wherein R is an organic group containing an acryloxy, methacryloxy, or a vinyl group; and R′ and R″ are independently selected from H and a second organic group. The second organic group may be saturated or unsaturated. Suitable phosphorus acid monomers include dihydrogen phosphate-functional monomers such as dihydrogen phosphate esters of an alcohol in which the alcohol also contains a polymerizable vinyl or olefinic group, such as allyl phosphate, mono- or diphosphate of bis(hydroxy-methyl) fumarate or itaconate, derivatives of (meth)acrylic acid esters, such as, for examples phosphates of hydroxyalkyl(meth)acrylates including 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylates, and the like. Other suitable phosphorus acid monomers are phosphonate functional monomers, disclosed in WO 99/25780 A1, and include vinyl phosphonic acid, allyl phosphonic acid, 2-acrylamido-2-methylpropanephosphonic acid, &agr;-phosphonostyrene, 2-methylacrylamido-2-methylpropanephosphonic acid. Further suitable phosphorus functional monomers are 1,2-ethylenically unsaturated (hydroxy)phosphinylalkyl (meth)acrylate monomers, disclosed in U.S. Pat. No. 4,733,005, and include (hydroxy)phosphinylmethyl methacrylate. Preferred phosphorus acid monomers are dihydrogen phosphate monomers which include 2-phosphoethyl (meth)acrylate, 2-phosphopropyl (meth)acrylate, 3-phosphopropyl (meth)acrylate, and 3-phospho-2-hydroxypropyl (meth)acrylate.
The comonomer is an ethylenically unsaturated monomer which is not a phosphorus acid monomer and is copolymerizable with an ethylenically unsaturated phosphorus acid monomer. Suitable comonomers include styrene, butadiene, &agr;-methyl styrene, vinyl toluene, vinyl naphthalene, ethylene, propylene, vinyl acetate, vinyl versatate, vinyl chloride, vinylidene chloride, acrylonitrile, methacrylonitrile, (meth)acrylamide, various C
1
-C
40
alkyl esters o
Bardman James Keith
Brown Ward Thomas
Larson Gary Robert
Rosano William Joseph
Greenblatt Gary N.
Rohm and Haas Company
Truong Duc
LandOfFree
Polymer composition and monomer composition for preparing... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Polymer composition and monomer composition for preparing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Polymer composition and monomer composition for preparing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3192384