Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2001-06-28
2002-11-12
Michl, Paul R. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
Reexamination Certificate
active
06479566
ABSTRACT:
This application claims priority from European Application No. 00305726.2 filed on Jul. 6, 2000.
BACKGROUND OF THE INVENTION
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.
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 one embodiment of 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 wherein the binder comprises a blend of the rosin material and an auxiliary film-forming resin in ratio 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, dissociating or exchanging with seawater species to leave a polymer soluble in seawater, the blocking groups being selected from quaternary ammonium groups which form a quaternary ammonium salt of the polymer and quaternary phosphonium groups which form a quaternary phosphonium salt of the polymer, and 80-20% 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 acid-functional film forming polymer (A) whose acid groups are blocked by groups capable of hydrolyzing, dissociating or exchanging with seawater species to leave a polymer soluble in seawater is preferably an acid-functional polymer whose acid groups are blocked by quaternary ammonium groups which form a quaternary ammonium salt of the polymer. The quaternary ammonium group can be tetra-alkyl or it can contain one or more alkoxyalkyl, cycloalkyl, aryl or aralkyl groups. More generally the organic groups in the quaternary ammonium group may be saturated or unsaturated, aliphatic, cycloaliphatic, aromatic, aliphatic-aromatic or heterocyclic.
The quaternary ammonium moiety preferably contains at least one organic group containing at least 3 carbon atoms, advantageously at least 8 carbon atoms and preferably from 8 to 25 carbon atoms (for example 8 to 20 carbon atoms), and more especially from 12 to 25 carbon atoms. The polymers containing a relatively long chain quaternary ammonium group have a decreased rate of dissolution in seawater. Examples of such quaternary ammonium groups are dodecyl trimethyl ammonium, hexadecyl trimethyl ammonium, octadecyl trimethyl ammonium, oleyl trimethyl ammonium, benzyl dodecyl dimethyl ammonium, dodecyl dimethyl octyl ammonium or trioctyl methyl ammonium. Mixtures of quaternary ammonium groups can be used; for example an organic group having 8 to 20 carbon atoms can be derived from a naturally occurring material such as a natural fatty material. Examples of such mixed quaternary ammonium groups are trimethyl hydrogenated tallow ammonium, dimethyl di(hydrogenated tallow) ammonium or trimethyl coconut ammonium. The quaternary group can alternatively be derived from rosin, for example it can be the N,N,N-trimethyl derivative of the amine sold commercially as “Rosin Amine D”, being mainly dehydroabietyl trimethyl ammonium. Advantageously, the total number of carbon atoms in the quaternary ammonium moiety is 8 or more, preferably 12 or more (for example, from 12 to 40).
The acid-functional film forming polymer (A) whose acid groups are blocked by groups capable of hydrolyzing, dissociating or exchanging with seawater species to leave a polymer soluble in seawater is alternatively an acid-functional polymer whose acid groups are blocked by quaternary phosphonium groups which form a quaternary phosphonium salt of the polymer. The quaternary phosphonium group can be tetra-alkyl or it can contain one or more alkoxyalkyl, cycloalkyl, aryl or aralkyl groups. More generally the organic groups in the quaternary phosphonium group may be saturated or unsaturated, aliphatic, cycloaliphatic, aromatic, aliphatic-aromatic or heterocyclic. Examples of such quaternary phosphonium groups are tetrabutylphosphonium, tetraphenylphosphonium and stearyltributylphosphonium.
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 unsaturated co-monomer. The unsaturated carboxylic acid can for example be acrylic or methacrylic acid or an acid functional ester or amide of acrylic acid or methacrylic acid such as mono-2-(methacryloyloxy)ethyl succinate, mono-2-(methacryloyloxy)ethyl phthalate, 2-acrylamidoglycolic acid, or 3-acrylamido-3-methylbutyric acid. The unsaturated sulphonic acid can for example be 2-acrylamido-2-methylsulphonic acid (AMPS). The unsaturated comonomer can for example be an ester or amide of an alkyl, alkoxyalkyl, carbocylic or heterocyclic alcohol or amine with an unsaturated carboxylic acid, such as methyl acrylate or methacrylate, butyl acrylate or methacrylate and isobornyl acrylate or methacrylate and the like. Alternatively the unsaturated co-monomer may be a vinylic compound, for example styrene, vinyl pyrollidone or vinyl acetate.
The acid-functional film forming polymer (A) whose acid groups are blocked by quaternary ammonium groups which form a quaternary ammonium salt of the polymer can be prepared by reaction of a polymer containing acid or acid-salt groups with a quaternary ammonium compound. Alternatively, it c
Finnie Alistair Andrew
Fox John
Lines Robert
International Coatings Limited
Michl Paul R.
Vickrey David H.
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