Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2001-09-24
2003-05-06
Sanders, Kriellion A. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C106S016000
Reexamination Certificate
active
06559202
ABSTRACT:
This application is the national phase of International Patent Application No. PCT/EP00/00398, filed on Jan. 18, 2000, and which claims priority of European Patent Application No. 99300378.9, filed Jan. 20, 1999.
This invention relates to antifouling paint. An antifouling paint is used as a top coat on ships' hulls to inhibit the settlement and growth of marine organisms such as barnacles and algae, generally by release of a biocide for the marine organisms.
BACKGROUND OF THE INVENTION
Traditionally, antifouling paints have comprised a relatively inert binder with a biocidal pigment which is leached from the paint. Among the binders which have been used are vinyl resins and rosin. The vinyl resins are seawater-insoluble and paints based on them use a high pigment concentration so that there is contact between pigment particles to ensure leaching. Rosin is a hard brittle resin which is very slightly soluble in seawater. Rosin-based antifouling paints have been referred to as soluble matrix or eroding paints. The biocidal pigment is very gradually leached out of the matrix of rosin binder in use, leaving a skeletal matrix of rosin which becomes washed off the hull surface to allow leaching of the biocidal pigment from deep within the paint film.
Many successful antifouling paints in recent years have been “self-polishing copolymer” paints based on a polymeric binder to which biocidal tri-organotin moieties are chemically bound and from which the biocidal moieties are gradually hydrolyzed by seawater, as described for example in GB-A-1457590. Self-polishing copolymer paints which release non-biocidal moieties are described in EP-A-69559, EP-A-204456, EP-A-529693, EP-A-779304, WO-A-91/14743, WO-A-91/09915, GB-A-231070 and JP-A-9-286933.
U.S. Pat. No. 4,675,051 describes a marine antifouling paint which is gradually dissolved in seawater and which comprises a binder which is a resin produced by the reaction of rosin and an aliphatic polyamine containing at least one primary or secondary amine group. EP-A-802243 describes a coating composition comprising a rosin compound, a polymer containing organisilyl ester groups and an antifoulant.
Rosin is not a very good film-former, and it is known to add other film-forming resins to rosin based antifouling paints. This has sometimes led to paints which were difficult to wash off the hull surface. The present invention seeks to improve rosin-based antifouling paints with respect to the strength of the paint film and/or the reliable eroding away of the rosin-based paint matrix after biocide has been leached from the paint.
SUMMARY OF THE INVENTION
An antifouling paint according to the present invention has a binder comprising a rosin material and an auxiliary film-forming resin, the paint including an ingredient having marine biocide properties, characterized in that the binder comprises a blend of the rosin material and an auxiliary film-forming resin in a ratio of 20:80 to 95:5 by weight, the auxiliary film-forming resin comprising 20-100% by weight of an acid-functional film-forming polymer (A) whose acid groups are blocked by groups capable of hydrolyzing or dissociating to leave a polymer soluble in sea water, the blocking groups being selected from divalent metal atoms bonded to a monovalent organic residue, divalent metal atoms bonded to a hydroxyl residue and monoamine groups which form an organic solvent soluble amine salt of the polymer, and 80-0% by weight of a non-hydrolyzing water-insoluble film-forming polymer (B).
DETAILED DESCRIPTION OF THE INVENTION
The rosin material is preferably rosin, particularly wood rosin or alternatively tall rosin or gum rosin. The main chemical constituent of rosin is abietic acid. The rosin can be any of the grades sold commercially, preferably that sold as WW (water white) rosin. The rosin material can alternatively be a rosin derivative, for example a maleinised or fumarised rosin, hydrogenated rosin, formylated rosin or polymerised rosin, or a rosin metal salt such as calcium, magnesium, copper or zinc rosinate.
The film-forming polymer (A) capable of hydrolyzing or dissociating to a polymer soluble in sea water is most preferably a hydrolysable polymer having at least one side chain bearing at least one terminal group of the formula:
wherein X represents
M is a metal selected from zinc, copper and tellurium; x is an integer of 1 to 2; R represents an organic residue selected from
and R1 is a monovalent organic residue, as described in EP-A-204456.
Such a hydrolysable polymer is preferably an acrylic polymer in which X represents
M is copper and R represents
The parent acrylic polymer having a —COOH group in place of —X—[O—M—R]
x
preferably has an acid value of 25-350 mg KOH/g. Most preferably the hydrolysable polymer has a copper content of 0.3-20% by weight and R
1
is the residue of a high boiling organic monobasic acid. Such hydrolysable polymers can be prepared by the processes of EP-A-204456 and EP-A-342276. The copper-containing film-forming polymer (A) is preferably a copolymer comprising an acrylic or methacrylic ester whose alcohol residue includes a bulky hydrocarbon radical or a soft segment, for example a branched alkyl ester having 4 or more carbon atoms or a cycloalkyl ester having 6 or more atoms, a polyalkylene glycol monoacrylate or monomethacrylate optionally having a terminal alkyl ether group or an adduct of 2-hydroxyethyl acrylate or methacrylate with caprolactone, as described in EP-A-779304.
The hydrolysable film-forming polymer (A) can alternatively be a carboxylic acid-functional polymer, for example a copolymer of acrylic or methacrylic acid with one or more alkyl acrylate or methacrylate, at least some of the acid groups of which have been converted to groups of the formula —COO—M—OH, where M is a divalent metal such as copper, zinc, calcium, magnesium or iron, as described in GB-A-2311070.
The film-forming polymer (A) can alternatively be a salt of an amine, preferably an amine containing at least one aliphatic hydrocarbon group having 8 to 25 carbon atoms and an acid-functional film-forming polymer as described in EP-A-529693. The acid-functional polymer is preferably an addition copolymer of an olefinically unsaturated carboxylic acid, sulphonic acid, acid sulphate ester, phosphonic acid or acid phosphate ester and at least one olefinically unsaturated co-monomer. The unsaturated carboxylic acid can for example be acrylic or methacrylic acid. The unsaturated sulphonic acid can for example be 2-acrylamido-2-methylpropane sulphonic acid (AMPS), for example the film-forming polymer (A) may preferably be an amine sulphonate copolymer containing units of an organocyclic ester as described in our co-pending application GB 9801747.8.
The non-hydrolyzing water-insoluble film-forming polymer (B) can for example be a vinyl ether polymer, for example a poly(vinyl alkyl ether) or a copolymer of a vinyl alkyl ether with vinyl acetate or vinyl chloride, an acrylate ester polymer such as a homopolymer or copolymer of one or more alkyl acrylates or methacrylates which preferably contain 1 to 6 carbon atoms in the alkyl group and may contain a co-monomer such as acrylonitrile or styrene, or a vinyl acetate polymer such as polyvinyl acetate or a vinyl acetate vinyl chloride copolymer. The polymer (B) can alternatively be a polyamine, particularly a polyamide having a plasticising effect such as a polyamide of a fatty acid dimer or the polyamide sold under the Trademark “Santiciser”.
We have found that the paints of the invention have the optimum combination of film-forming and eroding properties when the non-hydrolyzing water-insoluble film-forming polymer (B) is present in the composition, albeit as a minor proportion of the auxiliary film-forming resin. Most preferably the weight ratio of rosin to total auxiliary film-forming resin is from 25:75, 50:50 or 55:45 up to 80:20. The hydrolyzing or dissociating film-forming polymer (A) preferably forms at least 30, most preferably at least 50, up to 80 or 90% by weight of the auxiliary film-forming resin, the non-h
Finnie Alistair Andrew
Fox John
Akzo Nobel N.V.
Parker Lainie E.
Sanders Kriellion A.
Vickrey David H.
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