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
2001-05-07
2003-09-23
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...
C524S806000, C524S837000, C524S838000, C524S845000, C526S273000, C526S266000, C526S279000, C526S318300, C526S328500
Reexamination Certificate
active
06624243
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to functionalized copolymers in the form of their aqueous dispersions or water-redispersible powders, to processes for preparing them, and to their use.
2. Background Art
It is known that by using hydrolyzable vinylsilanes in the preparation of polymer dispersions, it is possible to obtain improvements in the properties as binders for paints. For instance, DE-C 2148457 (GB-A 1407827) discloses that use of aqueous dispersions comprising polymers containing copolymerized silanol groups makes it possible to enhance the wet adhesion of architectural coating compositions on a wide variety of substrates. EP-A 327376 describes the preparation of polymer dispersions based on vinyl esters, where ethylenically unsaturated alkoxysilane monomers are copolymerized by including a portion of the silane monomers in the initial charge prior to the polymerization. The polymer dispersions are recommended for preparing paints having good wet abrasion values. EP-A 327006 (U.S. Pat. No. 5,576,384) discloses low-VOC (VOC=volatile organic compounds) emulsion paints and plasters prepared using dispersions comprising copolymers containing hydrolyzable silane units. The dispersion is stabilized using hydroxyethylcellulose, nonionic emulsifier, and vinylsulfonate.
A disadvantage of the polymer dispersions known to date is that they do not bring about a general improvement in wet adhesion but instead act very differently in the various paint formulations. For instance, in a silicate-rich formulation a dispersion may have good wet abrasion resistance, whereas, if a greater amount of carbonate filler is used in the formulation, the same dispersion may lead only to paints having poor wet abrasion resistance.
SUMMARY OF THE INVENTION
An object of the invention was therefore to develop polymers which lead to coating compositions, for example, paints, which have very good wet abrasion resistance in a variety of paint formulations, for example in both silicate-rich and carbonate-rich formulations.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
The invention provides functionalized copolymers in the form of their aqueous dispersions or in the form of water-redispersible powders, the copolymers comprising the reaction product of:
a) one or more monomers selected from the group consisting of vinyl esters of unbranched or branched alkylcarboxylic acids having 1 to 15 carbon atoms, methacrylic esters and acrylic esters of alcohols having 1 to 15 carbon atoms, vinyl aromatics, olefins, dienes, and vinyl halides,
b) from 0.05 to 5.0% by weight of one or more ethylenically unsaturated, hydrolyzable silicon compounds and/or hydrolyzable epoxysilanes, aminosilanes, or mercaptosilanes,
c) from 0.05 to 5.0% by weight of one or more ethylenically unsaturated epoxide monomers,
d) from 0 to 2.0% by weight of one or more ethylenically unsaturated 1,3-dicarbonyl monomers,
the figures in % by weight being based in each case on the overall weight of the monomers a) used.
Suitable vinyl esters are vinyl esters of unbranched or branched carboxylic acids having 1 to 15 carbon atoms. Preferred vinyl esters are vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl laurate, 1-methylvinyl acetate, vinyl pivalate, and vinyl esters of &agr;-branched monocarboxylic acids having 5 to 11 carbon atoms, for example, VeoVa9
R
or VeoVa10
R
vinyl esters (trade names of Shell). Vinyl acetate is particularly preferred.
Suitable acrylic acid or methacrylic acid ester monomers are esters of unbranched or branched alcohols having 1 to 15 carbon atoms. Preferred methacrylic esters or acrylic esters are methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, n-, iso- and tert-butyl acrylate, n-, iso- and tert-butyl methacrylate, 2-ethylhexyl acrylate, and norbornyl acrylate. Particular preference is given to methyl acrylate, methyl methacrylate, n-, iso- and tert-butyl acrylate, 2-ethylhexyl acrylate, and norbornyl acrylate.
Suitable dienes include 1,3-butadiene and isoprene. Examples of copolymerizable olefins include ethene and propene, while as vinyl aromatics, styrene and vinyl toluene may be mentioned. Examples of vinyl halides include vinyl chloride, vinylidene chloride or vinyl fluoride, preferably vinyl chloride.
The comonomers a) are preferably selected so as to give aqueous copolymer dispersions and aqueous redispersions of the copolymer powders, which, without the addition of film forming auxiliaries, have a minimum film formation temperature, MFFT, of <10° C., preferably <5° C., in particular from 0° C. to 2° C. The skilled worker is aware, based on the glass transition temperature, Tg, of which monomer or monomer mixtures can be used for this purpose. The Tg of the polymers may be determined conventionally, for example by means of differential scanning calorimetry (DSC). The Tg may also be approximated in advance by means of the Fox equation. According to T. G. Fox, BULL. AM. PHYSICS SOC. 1, 3, page 123 (1956), 1/Tg=x
1
/Tg
1
+x
2
/Tg
2
+ . . . +x
n
/Tg
n
, where x
n
is the mass fraction (% by weight/100) of the monomer n, and Tg
n
is the glass transition temperature, in degrees, of the homopolymer of the monomer n. Tg values for homopolymers are listed in POLYMER HANDBOOK, 2nd Edition, J. Wiley & Sons, New York (1975).
If desired, it is possible to copolymerize from 0.05 to 10% by weight, based on the overall weight of the monomers a) used, of auxiliary monomers. Examples of auxiliary monomers are ethylenically unsaturated monocarboxylic and dicarboxylic acids, preferably acrylic acid, methacrylic acid, fumaric acid, and maleic acid; ethylenically unsaturated carboxamides and carbonitriles, preferably acrylamide and acrylonitrile; monoesters and diesters of fumaric acid and maleic acid such as the diethyl and diisopropyl esters and also maleic anhydride, ethylenically unsaturated sulfonic acids and their salts, preferably vinylsulfonic acid and 2-acrylamido-2-methylpropanesulfonic acid. Further examples are precrosslinking monomers such as polyethylenically unsaturated comonomers, examples being divinyl adipate, diallyl maleate, allyl methacrylate, butanediol diacrylate, and triallyl cyanurate, or postcrosslinking comonomers, examples being acrylamidoglycolic acid (AGA), methylacrylamidoglycolic acid methyl ester (MAGME), N-methylolacrylamide (NMA), N-methylolmethacrylamide, N-methylolallyl carbamate, alkyl ethers and esters such as the isobutoxy ethers or esters of N-methylolacrylamide, of N-methylolmethacrylamide, and of N-methylolallyl carbamate.
Preference is given to the copolymer compositions indicated below, which may further comprise the comonomer fractions b), c), and, if desired, d), and also auxiliary monomer fractions, in the stated amounts, and where the copolymer composition is chosen so that the aqueous dispersion obtainable therewith has an MFFT of <10° C., preferably <5° C., in particular from 0° C. to 2° C., so that there is no need for a film forming auxiliary:
vinyl ester copolymers of vinyl acetate with other vinyl esters such as vinyl laurate, vinyl pivalate, vinyl 2-ethylhexanoate, vinyl esters of an alpha-branched carboxylic acid having 5 to 11 carbon atoms, especially vinyl esters of Versatic acid having 9 or 10 carbon atoms (i.e., VeoVa9
R
, VeoVa10
R
);
vinyl ester-ethylene copolymers, such as vinyl acetate-ethylene copolymers, which, if desired, further comprise other vinyl esters such as vinyl laurate, vinyl pivalate, vinyl 2-ethylhexanoate, vinyl esters of an alpha-branched carboxylic acid having 5 to 11 carbon atoms, especially vinyl esters of Versatic acid having 9 or 10 carbon atoms or fumaric or maleic diesters;
vinyl ester-ethylene-vinyl chloride copolymers, containing as vinyl esters preferably vinyl acetate and/or vinyl propionate and/or one or more copolymerizable vinyl esters such as vinyl laurate, vinyl pivalate, vinyl 2-ethylhexanoate, vinyl esters of an alpha-branched carboxylic acid having 5 to
Ball Peter
Büppelmann Klaus
Kotschi Udo
Stark Kurt
Tschirner Peter
Brooks & Kushman P.C.
Lee Rip A.
Wacker Polymer Systems GmbH & Co. KG
Wu David W.
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