GB2411405A

GB2411405A - Polymer composition containing copper

Info

Publication number: GB2411405A
Application number: GB0400725A
Authority: GB
Inventors: Richard John Foster
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-01-14
Filing date: 2004-01-14
Publication date: 2005-08-31
Also published as: WO2005068563A1; GB0400725D0

Abstract

A material suitable for inhibiting the growth of marine organisms on immersed surfaces comprises metallic copper powder dispersed in a matrix, wherein there is further included a fugitive additive. In use, a coating formed from the material is rendered at least partially porous to increase the amount of copper exposed. The fugitive additive may be a volatile or water-soluble liquid or a water-soluble solid, for example, butyl oxitol, isopropyl oxitol, methyl diproxitol, or sodium bicarbonate. The matrix is preferably a plastics resin, such as an epoxy resin.

Description

1 241 1 405

ANTI-FOULING COATING

The present invention relates to coatings for hindering the formation of marine growths on immersed surfaces. s

The use of copper sheathing or copper-rich paints or coatings to prevent the growth on ship or boat hulls is well-known. Copper sheathing was used widely on larger wooden vessels but has fallen into die-use since the advent of metal hull construction because of the electrolytic corrosion of the hull material. Also it is diff cult to attach copper lo sheathing to a metal hull. Copper sheathing never was widely adopted for use with smaller vessels such as yachts and fishing vessels; these have tended to rely on anti- fouling paints and coatings containing copper. The effectiveness of such paints and coatings is a function of the amount of copper which actually is exposed to the water in which the vessel or structure upon which the paint or coating is applied is immersed.

is None of the existing copper-rich paints and coatings has been found to be entirely satisfactory.

It is an object of the present invention to provide an improved coppercontaining material no for the inhibition of the growth of marine organisms of surfaces immersed in water.

According to the present invention there is provided a material for use to inhibit the growth of marine organisms upon immersed surfaces, comprising metallic copper powder dispersed in a matrix material wherein there is included a material adapted to act as fugitive additive such that, in use, a coating formed of the said material is rendered at least partially porous thereby to increase the surface area of copper exposed to the environment of the coating.

Preferably, the matrix material is a plastics resin. The material adapted to act as a fugitive additive may be a water-soluble solid or liquid, or a volatile liquid.

The proportion of fugitive additive relative to the matrix material may lie in the range of 0.1 to 50% by weight.

lo The invention will now be described, by way of example only, with reference to the following, examples of anti-fouling coatings embodying the invention.

Copper-based anti-fouling paints and coatings rely for their operation on the leaching and/or abrasion of copper ions or coppers salts from their surfaces as a result of the immersion and/or movement of water past the anti-fouling material. The amount of copper ions or salts which can be released from the copper-containing material is dependent upon the surface area of the material exposed to the water.

The present invention enhances the effective rate of release of the copper ions or salts by to increasing the actual exposed surface area compared with the nominal area to which the anti-fouling material is applied. This is achieved by making at least the surface region of the anti-fouling material porous by including in a matrix material, usually but not necessarily, an epoxy resin material in which metallic copper is dispersed an additional component which is adapted to act as a fugitive additive, the loss of which renders the matrix material porous, so greatly increasing the exposed surface area of the coating relative to its nominal surface area, and hence also increasing the exposure of the copper contained in the anti-fouling material to its environment.

The additive material preferably is a liquid which does not react with any of the components of the matrix material, which is trapped in the matrix material as it cures and then slowly diffuses through the matrix material to evaporate or be dissolved, so leaving the matrix material with a slightly porous structure. Alternatively, the additive material could be in the form of fine powder of a soluble solid such as sodium bicarbonate.

When the matrix material is a plastics resin such as an epoxy resin, suitable materials for use as the fugitive additive are high boiling point solvents such as butyl oxitol (2-butoxy ethanol); isopropyl oxitol (2-isopropoxyethanol); methyl di proxitol [1- (1-methoxypropoxy)-2-proponol].

Methyl di proxitol particularly is preferred because it easily can be incorporated in plastics resin systems in place of some of the existing solvent, is soluble in water, has a very low evaporation rate, is readily biodegradable and does not big-accumulate.

to The amount of fugitive additive can be from 0.1 to 50% of the solid (non-volatile) component of the matrix material, but preferably should lie in the range 2.5 to 15% of the solids (non-volatile) content of the matrix material. as

EXAMPLE I

COPPER ANTIFOULING FORMULATION, 2.5% FUGITIVE ADDITIVE, s CALCULATED ON SOLID RESIN COMPONENTS

Description Materials WtKgs

75% solid 1 type EpoxyresinDER671X75 181.89 epoxy resin in xylene Flexibilising hydrocarbon resin Novares LA300 12.41 Air release agent BYK: A530 0.99 Solvent Methyl iso butyl ketone 16.12 Fugitive additive Methyl di proxitol % on resin (2.5%) 3.72 Thixotropic agent Silica Wacker N20 7.28 Thixotropic agent Byk 605R 2.55 Hardener 20% of ep resin solids Hardener 27.28 Copper powder 747.75 Totals 999 99

EXAMPLE 2

COPPER ANTIFOULING FORMULATION,, 5% FUGITIVE ADDITIVE,

CALCULATED ON SOLID RESIN COMPONENTS

Description Materials WtKgs

75% solid 1 type Epoxy resin DER671X75 181.89 epoxy resin in xylene Flexibilising hydrocarbon resin Novares LA300 12.41 Air release agent BYK A530 0.99 Solvent Methyl iso butyl ketone 12.40 3s Fugitive additive Methyl di proxitol % on resin (5%) 7.44 Thixotropic agent Silica Wacker N20 7.28 Thixotropic agent Byk 605R 2.55 Hardener 20% of ep resin solids Hardener 27.28 Copper powder 747.75 Totals 999.99

EXAMPLE 3

COPPER ANTIFOULING FORMULATION, 10% FUGITIVE ADDITIVE, CALCULATED Old SOLID RESIN COMPONENTS

Description MaterialsWt Kgs

75% solid I type Epoxy resin DER671X75181.89 epoxy resin in xylene Flexibilising hydrocarbon resin Novares LA30012.41 Air release agent BYK A5300.99 Solvent Methyl iso butyl ketone4.96 IS Fugitive additive Methyl di proxitol % on resin (10%)14.88 Thixotropic agent Silica Wacker N207.28 Thixotropic agent Byk 605R2.55 Hardener 20% of ep resin solids Hardener27. 28 Copper powder747.75 Totals 1,000.00

2s EXAMPLE 4

COPPER ANTIFOULING FORMULATION, 12.5% FUGITIVE ADDITIVE, CALCULATED ON SOLII) RESIN COMPONENTS

Description MaterialsWt Kgs

75% solid 1 type Epoxy resin DER671X75181.89 3s epoxy resin in xylene Flexibilising hydrocarbon resin Novares LA30012. 41 Air release agent BYK A5300.99 Solvent Methyl iso butyl ketone12.40 Fugitive additive Methyl di proxitol % on resin (12.5%)18.60 Thixotropic agent Silica Wacker N207.28 Thixotropic agent Byk 605R2.55 Hardener 20% of ep resin solids Hardener27.28 Copper powder747.75 4s Totals 1,011.15 t In the aforementioned examples Epoxy resin DER 671X75 is manufactured by Vantico of Duxford, UK; Flexibilising resin Novares LA30D is manufactured by Rutgers of P.O. Box 120552 s DUISBURG, Germany; Air release agent BYK 1530 and thixotropic agent BYK 605 R are manufactured by BYK of Chemie GMBH, Wesel, Germany and Thixotropic agent Silica Wack N20 is manufactured by Wacker of Chemie, D81737, Germany.

Claims

A material for use to inhibit the growth of marine organisms upon immersed surfaces, comprising metallic copper powder dispersed in a matrix material wherein there is included a material adapted to act as fugitive additive such that, in use, a coating formed of the said material, is rendered at least partially porous thereby to increase the surface area of copper exposed to the environment of the coating.
2. A material according to claim 1 wherein the proportion of material adapted to act as a fugitive additive relative to the insoluble solids content of the matrix material lies in the range 0.1 to 50% by weight.
3. A material according to claim 2 wherein the proportion of material adapted to act as a fugitive additive relative to the insoluble solids content of the matrix material lies in the range I to 15% by weight.
4. A material according to any of claims I to 3 wherein the material adopted to act as a fugitive is a volatile or water-soluble liquid.
5. A material according to any of claims 1 to 3 wherein the material adapted to act as a fugitive additive is a water-soluble solid material.
6. A material according to claim 5 wherein the material adapted to act as a fugitive additive is sodium bicarbonate.
7. A material according to any preceding claim wherein the matrix material includes a plastics resin.
8. A material according to claim 6 wherein the plastics resin is an epoxy resin.
9. A material according to any of claims l to 4 or claim 7 or claim 8 wherein the material adapted to act as a fugitive additive comprises butyl oxitol (2-butoxyethanol); isopropyl oxitol (2-isopropoxyethanol); or methyl-di-proxitol [1-(methoxy propoxy)-2
1 0 propanol].

lo. A material according to claim 8 wherein the material adapted to act as a fugitive additive is methyl-di-proxitol]1-(l-methoxy propoxy)-2propanol].
11. A material for use to inhibit the growth of marine organisms substantially as hereinbefore described.