US1421914A - Antifouling composition - Google Patents

Description

comma R Pusnc UNITED STATES Cross Reference PATENT OFFICE.

GEORGE D. COLEMAN, DECEASED, LATE OF BUFFALO, NEW YORK, BY mm s COLEMAN, EXECUTBIX, OF REVERE, MASSACHUSETTS.

ANTIFOULHIG COMPOSITION.

110 Drawing.

To all whom it may concern:

Be it known that GEORGE D. COLEMAN, de-

' ceased, late a citizen of the United States, re-

lant carbonaceous spfisfiince, such aslas siding at Buffalo, New York, did invent certain new and useful Improvements in Antifouling Composition; and I, NELLIE S. CoLE- MAN, of Revere, in the county of Suffolk and State of Massachusetts, his executrix, do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to a compound suitable for application to the bottom of a vessel or to any other object which is exposed to the destructive effects of seawater and the organisms therein.

Various compounds have been heretofore proposed for use in coating the bottoms of vessels or other sub-aqueous surfaces, these compounds containing copper in finelydivided form with the object of preventing the penetration of, or adhesion to the surface so protected, of barnacles, teredos and other a uiatic organisms, upon which the salts which are formed by the action of the water upon the copper have a poisonous or repellant effect. The present invention relates to a compound of this character, and

the object of the invention is to produce a compound which will form a coating which not only is strong, durable and tenacious, but which also is so composed that it will continuously present, at its exposed surface, sufiicient copper or the salts thereof to ellet:- tually repel or destroy organisms damaging to the surface protected.

In previously proposed compounds of the kind in question c o er, usually in finelydivided metallic form, has been combined with apin der or matrix of some waterrgpelo1 am or varnish the'c?)- r partic es be- P a Pp mg di's semiiiat'ed throughout the binder.

Such coatings have, however, been lacking in mechanical strength and durability, and they have also had the disadvantage that only the copper particles close to the outer surface have been available for any effective action, the particles buried within the body of the binder being too effectually preserved from contact with the water, and thereby Specification of Letters Patent.

Application filed November's, 1916. Serial No. 129,393.

Patented July 4,1922.

protected from its solvent action. To avoid the disadvantages of such previously-proposed compounds the present inventor has previously devised methods of producing protective coatings in which the copper particles are all located at the outer surface, so as to be entirely available for solution and effective action. These methods involve the application of the copper particles to a coat of moist or tacky paint or binding material and the subsequent operation of hammering, burnishing, or soldering the particles to bring them to a smooth and substantially continuous surface.

Examiner The inventor has discovered that an efiective antifouling coatin withou e oper atioiTs" ast referred to, and by the use of a compound throughout which the copper pzartiglgs are uniformly disseminate lns a ofb'ing segregated at the surface, provided the blnder with which the copper is incorporated'i's'bf such a character as to permit water to penetrate to some extent within its outer surface and thus have may be produced access to the copper particles incorporated therein, and hehas discovered that abinder consisting principally or wholly of i h w cteris-' draulic cement has the required chara t1cs, an pro uces, in addition, a coating having substantially greater strength and durability than those in which the binding material is of a carbonaceous or organic character, such as the tarry, resinous, or oily substances previously proposed for this purpose. Accordingly, the resent invention, in its broadest aspect, resi es in the use, as the basis of the compond, of a hydraulic cement such as Portland cement, intimately mixed with co er or cupr c material in a finelydivide orm.

While the hydraulic cement may be used without admixture of other substances than the copper or cupric material, it is preferable to add to the cement comparatively equiva ent produced by crushing uartz. To increase the tensile strength of tfiFBaTtu-ial a i v r o i r i 106. COMPOSIlIUNS,

comma R PLASTIC Hammer Cross Reference be a ed to t e compoun 0 increase the tenacity and facilitate hardening of the compound, calcium-h droxide may be employed. The principal content of copper may be in the form either of metallic copper 1n fine particles, or of some 0335i concentrate rich in (:0 er. This principal content of copper 15 ilius in a form in which it is substantially insoluble in pure water, and in which solution of the copper takes place only gradually in sea-water, in consequence of reactions produced by the sodium-chlorid dissolved in the water. In addition, however, to this principal content of the copper, it is desirable to use a compartively small amount of gppper in the form of a soluble salt, such as acetate or sul hate of co er. This soluble salt performs two useful functions. In the first place, it has an acid reaction by .which 'it neutralizes the caustic allgali 9f the cement, and thereby prevents this alkali from injuriously affecting the anchoring coat of paint or varnish upon which the present compound may be spread. In the second lace, the soluble co er-salt is immediate y available and soluldle at the surface of the coating formed from the present compound, so that even when the coating is first put into use and before the sodiumchlorid of the water has reacted to any substantial extent upon the relatively insoluble copper or cupric material, there is present at the surface of the coating a sufficient quantity of copper in immediately soluble form to secure the performance of the anti-fouling function of the coating.

Since the hydraulic cement is of a somewhat porous and hydroscopic character, the action of the sea-water is not limited to the surface of the cement, but the water may penetrate more or less into the body of the cement, thereby coming into contact with the copper embedded therein. The solution and removal of the copper at or near the surface of the cement, by increasing the porosity of the coating at this point, tends to promote flaking or erosion of the surface so far as is necessary to afford access of the water to the copper particles more deeply embedded in the coating, and in consequence of these facts a large part, if not the whole, of the copper ultimately .becomes available for the production of salts by which fouling of the surface is prevented.

The characteristic just described radically distinguishes the present compound, and the coating produced by it, from compounds in winch water-repellent substances are employed in place of the hydroscopic and comparatively porous cement of the present invention. Indeed, it is preferable to modify and diminish, to some extent, the natural porousness and hydroscopic character imggiwmlxr, such as mineral-wool or the p brous forms 0 stos and ma nesla, may

arted to the compound by the c ement, and for this purpose a small quantity of waterre ellant material may be incorporated in the mixture. It has been found that paraffine-waxjs a suitable material for this purose. p The in edients, and the proportions thereof, 0 a compound which has been found suitable for carrying out the present invention are as follows:

Parts by weight. Hydraulic cement 100 F inely-divided metallic copper or rich copper ore or concentrates of copper- 108 Sand or ground quartz 50 Mineral fiber Calcium hydroxid Parafline-wax 5 Acetate or sulphate of copper 6 jandnoLq rtzflmay be of a fineness sucli1 as todpass throu h a screen of 5?} or 60 mes an the are ne-wax may ave a melting point of approximately 135 degrees Fahrenheit.

The foregoin ingredients may be mingled in the fo lowing manner. The galcium-hydroxid, the acetate or sulphate of co er, and the parafiifie wax are t iturated, together with a weight of dry cement equal to the combined weight of weather ingredients, in a suitable mill, and the remainder of the cement is gradually added to the mixture. The compound so produced is then transferred to a suitable m'ixin machine and the sand, the gipriqgiateria and the ingraljfibla? are added to and m xed with the other ingredients, but withputgrindin Dry colorin -matter, such as a dar chrome men, may e added to the mixture 1f deare, and the compound may be packed dry and so kept until it is to be used for the production of an anti-fouling coating.

In producing a coating with the conipoung of tlge prespint ilrllvention, this comun may emixe eit er with purewater,

with an emulsion com risin wa er an er cent, more or less, of crude etroleum of ow s ecific gravity, and the plastic Il'llX- ture so ormed may be spread upon the surface which is to receive it, either in the form of a spray or by the use of a trowel or other suitable tool. In order to permit adhesion of the anti-fouling compound to the surface to which it is applied, and also to prevent electrolytic or chemical action between the compound and the surface, in the case of a metallic surface, such as that of the steel bottom of aship, it is preferable to coat this surface first with one or more coats of oil-paint or varnish, or other waterrepellant'material, and to a ply to, and partially embed in, the anclioring layer so formed, while it is still moist and tacky, particles of bonding and insulating material such as sand or brick-meal to afford a rough surface to which the cementitious compound will adhere, and to prevent or limit direct contact between the cementitious compound and the anchoring layer.

The compound of the present invention, instead of being mixed with water or an emulsion of water and non-drying oil as above described, may be mixed with a d in oil such as linseed oil and thus rendered plastic and suitable for application as a coatmg. The use of water is preferable, however, as the useful functions of some of the ingredients are more or less impaired by the presence of a wa'ter-repellant binder such as dried oil.

The invention is not limited to the embodiment thereof hereinbefore described, but may be embodied in various other forms within the scope of the'following claims.

The invention claimed is:-

1. An anti-fouling composition comprising an intimate mixture of hydraulic cement, cupric material substantially insoluble in water, and a soluble salt of copper.

2. An anti-fouling composition comprising an intimate mixture of hydraulic cement, and finely divided material containing copper in a substantially water insoluble form and a water soluble saltof copper.

3. An anti-fouling composition comprising an intimate mixture of hydraulic cement, calcium hydrate, and cupric material includin a soluble acid salt,

4. An antiouling composition comprising an intimate mixture of hydraulic cement, calcium hydrate, sand, mineral fiber, parafiine-wax, and cu ric material.

NELLIE' COLEMAN, Ewecutfia: of George D. Coleman, Deceased.