US1993354A - Process for the preservation of woven fabrics - Google Patents

Description

5 woven fabrics;

Patented Mar. 5, 1935 PATENT. o IcE PROCESS FOR THE PRESERVATION OF WOVEN FABRICS Phillip R. Andrews and Alexander Finlayson, Seattle, Wasln, assignors to Sealth Corporation, Seattle, Wash, a corporation of Washington No Drawing.

Application July 28, 1932,

Serial No. 625,524

5 Glaims.

Our present invention relates to a process for the preservation of wood and woven fabrics.

The object of this invention is the provision of a process for the preservation of wood and Broadly statedthe invention is believed to consist of a new process for deterring decay in woven fabrics or woody fibres. The process may be summarized as constituting three independent steps or phases, namely:

1. The incorporation into woven fabrics or wooden structures of a bimetallic couple, inactive in itself when such fabrics or wooden structures are not exposed in a decay promoting atmosphere.

2. The assumption of an electrolyte, which in all cases is the samemedium, which provides the breeding ground fordecay promoting organisms.

3. The complement of couple and electrolyte creating a galvanic cell, which is progressively productive of poisonous compounds.

All woven fabrics, having an organic origin, or composed of bast fibers and cellular tissues, as hemp, flax, jute, cotton; and all woody structures, are subject to rapid decay when exposed to the biochemical action of fungoid growths,

vegetable moulds, mildew and other microorganisms.

A common instance of this type of not and deterioration is manifested when the hulls of wooden ships, or fishing nets are exposed in,

water, either fresh or salt, but more especially in the latter due to the greater complexity of algae and bacterial life existing symbioticagyor i n' dependently in it. Not only are such organisms highly destructive through the rotting action they set up, but by the process of accretion they gradually increase in mass and build up to ponderous proportions, forming a footing or host for higher types of marine life, as larval Cirripedia, until the depending load upon the structure, (as in the example of nets),,becomes suflicient to rupture and tear it ap'artlk The baneful effect of barnacles adhering. to ships bottoms need not be elaborated. p 7 g s It is therefor desir'fble, inorder torestri'ct the rate of decay, to inhibit the formation of these growths; and to compass this end it is proposed by a new process torendertoxic to organic life all fabrics exposed to theirfaction.

The process is predicated upon a special adaptation of eiectro chemical phenomena to the production or generation of poisonous compounds in the fabric,-when such fabric is exposed in an environment of atmosphere or moisture otherwise favorable to the decaying atis iron coated with metallic zinc.

tacks of organic growths. But since this environment will also be favorable to the pre-arranged formation of poisonous compounds, and since these compounds will be produced at a greater rate, and prior to the genesis of viable organisms, 5 or while such are inchoate, the fabric will be rendered highly toxic and unsuited as a host for the parasites. When any metal is dissolving in a solution in direct contact with another metal having a lower 10 place ,in the electrochemical series, the rate of dissolution of the former is augmented. Thus if zinc and platinum be placed together in a dilute solution of sulphuric acid the zinc rapidly corrodes, forming soluble salts, while the platl5 inum is but little affected. The combination Zn: ;Pt is called a couple. It is, in fact, a small galvanic cell with zinc and platinum as electrodes connected by metallic contact. The acid solution is an electrolyte, containing dissociated ions. 20 Now, any aqueous solution containing dissolved salts will contain free ions, negatively and positively charged; ,it therefore becomes an electrolyte, and in this regard-all natural waters, since they contain dissolved salts, highly ionized, may 2 be considered natural electrolytes.

There are certain characteristic phenomena manifested by every galvanic or voltaic couple. To enumerate the most pertinent we have, (1),

the setting up of a weak electromotive. force be- 97 tween the two metals, (2), the ionization of the one which is more electropositive, or higher in the electrochemical series, and (3), the displacement of the cathode metal from its salts by the anode.

Now, it is axiomatic that any metal in the elec- 5 trochemical series can be made'one plate of a cell against another metal lower in the series. Thus any two dissimilar metals in contact with one another will form a voltaic couple, and when such a couple is placed, or fortuitously occurs in a suitable electrolyte, a current is set up, like a short-circuited cell. One of the metals becomes electropositive, the other'electronegative. The former will ionize in solution, producing salts, while the latter will remain unchanged.

' An example of this voltaic action may be understood by reference to galvanized iron, which The two metals form a couple. Atmospheric moisture, combin- 50 ing with the carbon dioxide of the .air forms dilute carbonic acid and becomes an electrolyte. The zinc, being more electropositive than the iron; (higher in the electromotive series), is the anodabecomes ionized, and forms'zinc carbon- 66 ate: unchanged.

Thus a process for preserving fabrics from the attacks of decaying organisms is made available by incorporating in the fabric, as part of its structure, a galvanic couple, which, when exposed in a medium propitious to the growth of "destructive parasites onthe fabric will also be favorable to the formation of poisonous salts by the couple. As already inferred, these poisonous salts will be formed at a greater rate than that of organic accretion and so render-the fabric inhibitory to the latter.

As a specific example of the employment of this process of preservation we may advert-to the consideration of wooden ships hulls, or perhaps one more facile would be its application to a the preservation of fishing nets from the incrustations of marine organisms.

In this instance we introduce into the cords of the net a metal, which will form poisonous salts, say copper. This metal may be employed either in the form of wire, colloidal particles or powder. If the copper is quite impure, containing elements less active and lower in the electrochemical series, we shall have the desired couple at once created and when the net is placed in the sea, rapid corrosion of the copper 'will take place with the formation of toxic compounds. However, since commercial copper is too free from impurities which would cause a sufliciently strong E. M. F. for rapid corrosion, it is necessary to introduce another metal, either higher or lower in the electrochemical series, but one which will either form poisonous salts from itself or cause the copper to do so. We may, for example use mercury, amalgamated with the copper to form a couple. The ocean with its high percentage of dissolved sodium chloride, highly ionized, becomes the electrolyte. The mercury is less active and lower in the series than in the copper, which at once ionizes and forms basic chlorides according to the formula;

Furthermore, since sea water carries hundreds of other ionized salts the copper will form more or less appreciable quantities of other poisonous compounds, and since mercury and all its salts are extremely toxic we have set up a highly inhibitory toxicity in the net.

If, on the other hand we use a metal higher in the electrochemical series to provide the other pole with copper in the couple, as for example zinc, this metal becomes the anode and will form chlorides and oxychlorides of the order;

This ZnzzCu couple can be introduced in the form of brass wire, which is an alloy of copper and zinc, and although the compounds produced in this case do not have nearly the toxicity of the Cu: :Hg system they are none the less very destructive to certain types of organisms. Zinc chloride in solution is commonly injected into wood to prevent decay. But, in any case, the couple must always be made up of metals which will produce poisonous compounds at the anodean ideal combination being copper and mercury. Copper and iron would thus be worthless; the iron would become the scaraficial metal forming harmless hydrates and preventing the copper from entering into any reaction productive of poisonous salts.

Under other conditions, when the fabric is not r 1,993,354 The iron is the cathode and remains a net immersed in brine, but perhaps a canvas,

or a cotton hose exposed to the action of fresh water, or a humid atmosphere, the electrochemical reactions would be the same although proportionately slower. Employing the coppermercury couple merely exposed to rain or moist air, but which are conditions productive of mildew or mould, the copper will form the well known green carbonates through the interaction with carbonic acid which has been described as occurring in the zinc-iron couple.

Conforming to the requirement of our process, that two metals are required to produce the necessary voltaic couple, it should be understood that the two metals may be introduced in metallic form or they may be introduced in some chemical combination which when subjected to the condition which will promote normal decay in the material treated, will have reactions which will make the two metals available for the creation of the galvanic cell action which is necessary to produce the poisonous salts required. Normally it has been found most satisfactory to use copper in some metallic form and to introduce the other metal of the electrochemical series either in its metallic form or by immersing, the fabric it is intended to preserve, in a solution of some compound of the second metal which, when under the proper conditions where a suitable electrolyte is present, will give the action corresponding to that of the two metals. As a specific example of this procedure we may immerse the fabric, (which has already been impregnated with metallic copper), in a solution of mercuric chloride. The mercury will be at once displaced from its salt and deposited upon the surface of the copper, setting free chlorine ions.

form of the metals will be used is dependent The choice as to which largely upon the fabric to be treated. The one. i

ever present requirement should be borne in mind, namely: that of arranging for the presence of metals which will provide for the formation of;

poisonous compounds mally equal to the treated.

over a period of time nor-, expected life of the fabric It has been found difilcult indeed tofulfill 1 this "condition by attempting to impregnate the fabric with poisonous compounds themselves as the elements which cause rot and decay tend to wash out the poisonous compounds, consequently it has been found most satisfactory to use at least in one of the metals in metallic form so that the production of a poisonous compound can be extended over a long period.

In certain instances, particularly in the making of canvas, fish netting, twine, hose and the like, it may be desirable not to subject the fabric to any dipping process. This can be avoided by immersing the copper wire before it is interwoven with the fabric in a solution of a mercury salt and allowing the copper wire to be plated with mercury or the same could be accomplished by wiping the wire with metallic mercury. Either of these methods will produce the desired bimetallic couple.

The foregoing. description is believed to clearly disclose a. preferred embodiment of our invention but it will be understood that this disclosure is merely illustrative and that such changes in the invention may be made as are fairly within the scope and spirit of the following claims.

What we claim is:

1. A process for the preservation of knotted, woven or twisted fabrics consisting of incorporatwill co-act with the bi-metallic couple to progres sively produce soluble, poisonous compounds.

2. A process for the preservation of knotted,

woven or twisted fabrics consisting of incorporating into fabric structures two metals of different electrochemical properties and immersing the whole in an electrolyte which will co-act with the two metals to produce a. bi-metallic couple capable of progressively producing soluble, poisonous compounds.

3. A process for the preservation of knotted, woven or twisted fabrics consisting of incorporating into fabric structures a metal such as copper, and a second metal of different electrochemical properties which will either form poisonous salts itself or cause the copper to do so and immersing the whole in an electrolyte which will co-act with the two metals to progressively produce soluble, poisonous compounds.

4. A process for preserving fabrics from the attacks of decaying organisms consisting of incorporating in the fabric, as part of its structure, a

, galvanic couple, which, when exposed in a medium propitious to the growth of destructive parasites on the fabric will also be" favorable to the formation of soluble, poisonous salts by the couple.

5. A process for preserving fabrics from the attacks of decaying organisms consisting of creating an unhealthy and toxic atmosphere in the immediate vicinity of materials immersed in water or exposed in moist atmosphere by incorporat ing in the fabric, as part of its structure, a galvanic couple, which, when immersed in an electrolyte, produces progressively, soluble, poisonous compounds which inhibit organic accretion.

PHILLIP R. ANDREWS. ALEXANDER FliNLAYSON.