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
2001-06-25
2003-07-08
Dawson, Robert (Department: 1712)
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...
C524S501000, C524S401000, C525S479000, C525S185000, C106S287130
Reexamination Certificate
active
06590026
ABSTRACT:
This application under 35 U.S.C. Section 371 of International Application Number PCT/FR99/02377 filed on Oct. 05, 1999.
The present invention relates to novel coating compositions, in particular paint compositions. These compositions can be used in various applications, such as water paints, roughcasts, transparent coatings, impregnations or semi-thick coatings (STC).
The prior art does not indicate a coating composition capable of correctly and satisfactorily crosslinking by condensation into an elastomer or a crosslinked material which confers, on the final application, for example in the form of a paint, a high wet abrasion resistance (WAR), a satisfactory impermeability to water and a satisfactory permeability to water vapor. In addition, the prior art does not indicate coating compositions which have a high and enduring stability on storage (maintenance of the content of VOCs or of alcohols produced in situ below a breakdown threshold of the composition).
One of the essential objectives of the present invention is thus to provide a novel coating composition which confers, on the final application, efficient water-repellency, that is to say high wet abrasion resistance (WAR), satisfactory impermeability to water, satisfactory permeability to water vapor and a satisfactory pearling effect. In addition, the novel coating composition has a high and enduring stability on storage.
More specifically, the novel coating composition developed, which forms the subject-matter of the present invention, comprises:
(A) 3 to 30 parts (solids content at approximately 50% by weight) of a latex composed of particles of organic (co)polymers exhibiting a glass transition temperature of between −20° C. and 50° C.,
(B) 0.05 to 5 parts (solids content at approximately 65% by weight) of an epoxyfunctionalized polyorganosiloxane emulsion,
(C) and 100 (solids content at approximately 75% by weight) parts of inorganic fillers.
In the context of the invention, the parts (A) and (B) form what is known as the binder of the coating composition.
The latex used in the context of the composition according to the invention is prepared from polymerizable monomers (1) chosen from styrene, butadiene, acrylic esters and/or vinyl nitrites.
The term “acrylic esters” denotes esters of acrylic acid and of methacrylic acid with C
1
-C
12
, preferably C
1
-C
8
, alkanols, such as methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate or isobutyl methacrylate.
The vinyl nitriles include those having from 3 to 12 carbon atoms, in particular acrylonitrile and methacrylonitrile.
Styrene can be replaced, in all or in part, by amethylstyrene or vinyltoluene.
Other ethylenically unsaturated monomers (2) which can be polymerized with the above monomers (1), the amount of which can range up to 40% by weight of the total of the monomers, can also be used for the preparation of the latex of the composition according to the invention. Mention may be made of:
(a) carboxylic acid vinyl esters, such as vinyl acetate, vinyl versatate or vinyl propionate,
(b) unsaturated ethylenic mono- and dicarboxylic acids, such as acrylic acid, methacrylic acid, itaconic acid, maleic acid or fumaric acid, and monoalkyl esters of the dicarboxylic acids of the type mentioned with alkanols preferably having 1 to 4 carbon atoms and their N-substituted derivatives,
(c) amides of unsaturated carboxylic acids, such as acrylamide, methacrylamide, N-methalolacrylamide or -methacrylamide,
(d) ethylenic monomers comprising a sulfonic acid group and its alkali metal or ammonium salts, for example vinylsulfonic acid, vinylbenzenesulfonic acid, a-acrylamido-methylpropanesulfonic acid or 2-sulfoethylene methacrylate,
(e) ethylenically unsaturated monomers comprising a secondary, tertiary or quaternary amino group or a heterocyclic group comprising nitrogen, for example vinylpyridines, vinylimidazole, aminoalkyl (meth)acrylates and aminoalkyl(meth)acrylamides, such as dimethylaminoethyl acrylate or methacrylate, di-tert-butylaminoethyl acrylate or methacrylate, dimethylaminomethylacrylamide or -methacrylamide, as well as zwitterionic monomers, such as sulfopropyl(dimethyl)aminopropyl acrylate, and the like,
(f) esters of (meth)acrylic acids with alkanediols preferably comprising 2-8 carbon atoms, such as glycol mono(meth)acrylate, hydroxypropyl mono(meth)acrylate or 1,4-butanediol mono(meth)acrylate, and monomers comprising two polymerizable double bonds, such as ethylene glycol dimethacrylate.
According to a preferred alternative form for the choice of the latex, the latter comprises, by weight:
25-90% and preferably 45-75% of styrene and/or acrylonitrile,
75-10% and preferably 55-25% of butadiene and/or acrylates,
0-20% and preferably 1-10% of unsaturated carboxylic acid,
and 0-40% and preferably 0-15% of other unsaturated ethylenic monomers.
The polymerization of the latex is carried out in a way known per se in an aqueous emulsion of the polymerizable monomers in the presence of at least one radical initiator and preferably of a transfer agent, for example of the mercaptan type, with a concentration of monomers in the reaction medium generally of between 20 and 60% by weight.
The polymerization can be carried out continuously, batchwise or semicontinuously with introduction of a portion of the monomers continuously and can be of the “seeded” or “incremental” type according to any alternative form known for the production of particles with a homogeneous and heterogeneous structure.
For the preparation of the latex, reference will be made, as non-limiting example, to the procedures disclosed in patent EP 599 676 on behalf of the present applicant company.
Mention may be made, as examples of inorganic fillers of the composition according to the invention, of milled quartz, kaolin, fumed silica, precipitated silica, calcium carbonate, barium sulfate, titanium oxide, talc, hydrated alumina, bentonite, calcium sulfoaluminate, and the like.
The epoxyfunctionalized polyorganosiloxanes of the composition according to the invention are linear and/or cyclic. Identical or different polyorganosiloxanes can be used within the same coating composition. These polyorganosiloxanes are composed of units of formula (I) and are terminated by units of formula (II) and/or are composed of units of formula (I) which are represented below:
in which:
the R
1
symbols are alike or different and represent:
a linear or branched alkyl radical comprising from 1 to 8 carbon atoms, the alkyl radicals preferably being methyl, ethyl, propyl and octyl,
a cycloalkyl radical comprising between 5 and 8 cyclic carbon atoms which is optionally substituted,
an aryl radical comprising between 6 and 12 carbon atoms which can be substituted, preferably phenyl or dichlorophenyl,
an aralkyl part having an alkyl part comprising between 5 and 14 carbon atoms and an aryl part comprising between 6 and 12 carbon atoms which is optionally substituted on the aryl part by halogens, alkyls and/or alkoxyls comprising 1 to 3 carbon atoms,
the Y′ symbols are alike or different and represent:
the R
1
group,
and/or an epoxyfunctional group, connected to the silicon of the polyorganosiloxane via a divalent radical comprising from 2 to 20 carbon atoms which can comprise at least one heteroatom, preferably oxygen,
and at least one of the Y′ symbols representing an epoxyfunctional group.
The linear polyorganosiloxanes can be oils with a dynamic viscosity at 25° C. of the order of 10 to 10 000 mPa·s at 25° C., generally of the order of 50 to 5000 mPa·s at 25° C. and more preferably still of 100 to 600 mPa·s at 25° C., or gums exhibiting a molecular mass of the order of 1000000.
When cyclic polyorganosiloxanes are involved, these are composed of units (II) which can be, for example, of the dialkylsiloxy or alkylarylsiloxy type. These cyclic polyorganosiloxanes exhibit a viscosity of the order of 1 to 5000 mPa·s.
Mention may be made, as examples of divalent radicals connecting an organofunc
Branlard Paul
Dorget Michel
Joanicot Mathieu
Mignani Gerard
Dawson Robert
Peng Kuo-Liang
Rhodia Chimie
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