Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2000-07-20
2003-09-30
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...
C106S015050, C106S016000
Reexamination Certificate
active
06627675
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to antifouling coatings. An antifouling coating is used as a top coat on ships' hulls and other surfaces such as fishing nets, oil rig supports, swimming pools and power station cooling inlets to inhibit the settlement and growth of aquatic organisms such as barnacles and algae, generally by release of a biocide for the aquatic organisms.
BACKGROUND ART
The most successful antifouling paints in recent years have been “self-polishing copolymer” paints based on a polymeric binder to which biocidal triorganotin moieties are chemically bound and from which the biocidal moieties are gradually hydrolysed by seawater, as described for example in GB-A-1457590. The polymer from which the triorganotin moieties have been hydrolysed becomes soluble in seawater, so that as the outermost paint layer becomes depleted of biocide it is swept off the surface of the hull by the movement of the ship through seawater. There has been a call for antifouling coatings which exhibit the “self-polishing” effect without necessarily releasing strongly biocidal triorganotin moieties. Self-polishing copolymer paints which release non-biocidal moieties are described for example in EP-A-69559 and WO-A-84/02915.
US-A-5116407 and EP-A-529693 describe an antifouling coating having marine biocidal properties and comprising as binder an acid-functional film-forming polymer whose acid groups are blocked by hydrolysable blocking groups which are monoamine groups forming organic-solvent-soluble amine salts of the polymer. JP-A-1-103672 discloses a similar composition. WO-A-91/09915 describes an antifouling coating which comprises a marine biocide and a binder which is a hydrolysable seawater-erodible polymer containing sulphonic acid groups in quaternary ammonium salt form. WO-A-96/03465 describes an antifouling coating composition comprising a water-erodible binder polymer having at least 3 limbs radiating from a central core, with protected acid functionality present in the limbs of the polymer. The protected acid functionality can be carboxylic or sulphonic acid groups blocked by a monoamine or quaternary ammonium group
JP-A-6-72807 describes a persistent underwater antifouling agent which contains a polymer of average molecular weight from 3000 to 40000 obtained by the polymerization of (a) the reaction product of a polymerizable unsaturated monomer which has a sulphonic acid group and at least one type of higher aliphatic amine represented by the general formula (I)
where R
1
represents a saturated or unsaturated aliphatic hydrocarbon group with 12 to 20 carbons, R
2
represents a hydrogen atom or an alkyl group with 1 to 6 carbons, and R
3
represents a hydrogen atom, an alkyl group with 1 to 6 carbons, a saturated or unsaturated aliphatic hydrocarbon group with 12 to 20 carbons, or an alkyl group with 1 to 6 carbons substituted with an amino group which may be substituted with an alkyl group with 1 to 6 carbons, or, alternatively, by the polymerization of the aforesaid reaction product (a) and some other polymerizable unsaturated monomer (b) which is copolymerizable therewith.
EP-A-232006 describes a water-erodible coating comprising an erodible polymer containing a hydrolysable sulphonate ester or sulphate ester group EP-A-429215 describes a process for preparing such a polymer.
SUMMARY OF THE INVENTION
An antifouling coating composition comprises a binder which is a salt of an amine containing at least one aliphatic hydrocarbon group having 8 to 25 carbon atoms and an addition copolymer of an olefinically unsaturated sulphonic acid, acid sulphate ester, phosphonic acid or acid phosphate ester and at least one olefinically unsaturated comonomer. The coating composition includes an ingredient having biocidal properties for aquatic organisms. The amine is preferably an amine having two aliphatic hydrocarbon groups each having 8 to 25 carbon atoms and the copolymer contains at least 5 mole % of units of an organocyclic ester or amide (A) of an olefinically unsaturated carboxylic acid. The organocyclic ester or amide (A) is preferably an isobornyl ester.
DISCLOSURE OF INVENTION
We have found that antifouling coating compositions based on a binder which is a salt of an amine having at least one aliphatic hydrocarbon group having 8 to 25 carbon atoms and an addition copolymer of an olefinically unsaturated sulphonic acid, acid sulphate ester, phosphonic acid or acid phosphate ester can exhibit a “self-polishing” effect. However, the presence of the highly hydrophilic sulphonate, sulphate, phosphonate or phosphate groups to render the copolymer “self-polishing” may lead to a weak water-swellable coating. We have found that this can be overcome by the use of hydrophobic comonomers, but that most hydrophobic comonomers such as lauryl methacrylate or butyl acrylate produce an undesirably soft copolymer of very low Tg when used in conjunction with long-chain amine salts, and that coatings based on such a soft copolymer may have lower mechanical strength when wet than is desired for use as an antifouling coating.
As disclosed in U.S. Pat. No. 5116407 and in JP-A-1-103672, amines containing one aliphatic or cycloaliphatic hydrocarbon group having 12 to 20 carbon atoms are generally toxic to aquatic organisms. There is a demand in some countries for a “self-polishing” antifouling paint in which the binder polymer is substantially non-toxic even though it is used with known biocides for aquatic organisms such as cuprous oxide. We have found that, contrary to the teaching of JP-A-6-72807, salts of a sulphonic acid copolymer with an amine having one methyl or ethyl group and two aliphatic hydrocarbon groups each having 8 to 25 carbon atoms are generally substantially non-toxic and can be used as the binder for a “self-polishing” antifouling coating. They are, however, equally as water-sensitive as other amine salts of sulphonic acid copolymers and are even softer than other amine salts. They can therefore be used in compositions including an ingredient having biocidal properties for aquatic organisms as the outermost coating on a substrate which is to be underwater in use so as to inhibit the settlement and growth of aquatic organisms.
According to one aspect of the present invention, an antifouling coating composition comprising a binder which is a salt of an amine containing at least one aliphatic hydrocarbon group having 8 to 25 carbon atoms and an addition copolymer of an olefinically unsaturated sulphonic acid, acid sulphate ester, phosphonic acid or acid phosphate ester and at least one olefinically unsaturated comonomer, the coating composition including an ingredient having biocidal properties for aquatic organisms, is characterised in that the amine is an amine having two aliphatic hydrocarbon groups each having 8 to 25 carbon atoms and the copolymer contains at least 5 mole % of units of an organocyclic ester or amide (A) of an olefinically unsaturated carboxylic acid. By an organocyclic ester or amide we mean an ester of an alcohol, or an amide of an amine, containing at least one saturated, unsaturated or aromatic ring which may be carbocyclic or heterocyclic and substituted or unsubstituted and in which the alcohol or amine group can be bonded to the ring directly or through an alkylene or oxyalkylene linkage.
The invention is described below with particular reference to sulphonic acid copolymers; in general acid sulphate ester, phosphonic acid and acid phosphate ester copolymers can be used as alternatives to sulphonic acid copolymers.
We have found that the organocyclic ester or amide comonomer tends to make the copolymer both more hydrophobic and harder, compared to polymers prepared using only conventional hydrophobic acrylate ester comonomers such as butyl acrylate, 2-ethylhexyl acrylate or lauryl methacrylate. Copolymers containing organocyclic ester or amide monomer units and units of a sulphonic acid salt of an amine having at least one long-chain hydrocarbon group have improved resistance to cold flow and improved mechanical properties in service in s
Finnie Alistair Andrew
Millichamp Ian Stuart
Overbeek Gerardus Cornelis
Van Geel Andrianus Antonius Johannes
Yeates Terry
International Coatings Limited
McGillycuddy Joan M.
Parker Lainie E.
Sanders Kriellion A.
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