US2920986A - Compounds for protection from vesicants - Google Patents

Description

COMPOUNDS FOR PRGTECTION FROM VESICANTS Edgar M. Faber and Herbert A. Scruton, Baltimore, Md, and Ralph W. Peakes, Washington, D.C.., assignors to the United States of America as represented by the Secretary of War as trustee No Drawing. Application April 13, 1939 Serial No. 267,720

Claims. (Cl. 117-168) (Granted under Title 35, US. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to us of any royalty thereon.

This invention relates in general to the treatment of cloth to render it protective against certain liquids, gases and vapors, and more particularly has reference to treatment of various fabrics to render them resistant to the penetration of vesicant chemical warfare agents.

It is well known that mustard gas (bis (beta chlorethyl) sulfide) and similar vesicants penetrate ordinary clothing and produce severe burns and many attempts have been made to provide clothing which would effectively protect persons exposed to such vesicants. Impermeable suits have been made which prevent the vesicants from reaching the wearers skin, but such clothing is uncomfortable, since it is also impermeable to air and moisture.

Developments have also produced chemicals which can be impregnated into clothing and which permit the normal passage of air and moisture, the chemicals reacting with mustard or other vesicants to render them harmless to the skin. This method of protection is very desirable, but many of the chemicals heretofore known for impregnating clothing have been so unstable in the presence of air, moisture, and sunlight that protection is secured for only a very limited time.

An object of this invention is to provide a method of treating clothing or fabrics to render them impervious to mustard or other vesicants while retaining their permeability to air, the fabrics being undamaged by the treatment.

Another object of this invention is to provide a method of treating clothing or fabrics to render them impervious to mustard gas or other vesicants, such treatment remaining efiective for long periods of time, even after repeated laundering and exposure to air and sunlight.

Another object of this invention is to provide a method of treating clothing or fabrics for the above purposes using an impregnating material for reacting with the vesicant agents in combination with a non-reacting binder. The binder should be chemically unreactive with the impregnating material (active compound), be insoluble in water so as to avoid leaching and be a solvent for the vesicants, thus forming a medium for contact between the vesicant and the impregnite.

Another object of this invention is to provide a method of treating clothing or fabric for the above purposes using an impregnating material, a binder and a volatile solvent. The volatile solvent is used to secure uniform distribution of the impregnite and the binder on the cloth.

Another object of this invention is to provide a method of treating clothing for the purpose of de-lousing the clothing and killing the eggs or nits of lice or other vermin.

Another object of this invention is to provide a method 2,929,986 Patented Jan. 12, 196i) of treating clothing or fabrics for the above purposes wherein the clothing or fabrics are first dried to remove moisture to thereby avoid chemical reaction between water and the other ingredients and are then treated with an impregnating material which will react with vesicant chemical warfare agents to form relatively non-vesicant compounds, the impregnating material and binder being dissolved in a volatile solvent.

These and various other objects will be apparent from the following description and appended claims, with the understanding that the ingredients used and the steps of the process may be varied without departing from the invention.

As above indicated, this invention relates to permeable fabrics and clothing which after treatment are not greatly different in respect to passage of air than fabrics not treated. Without interfering with the normal passage of air and perspiration, the impregnated permeable fabric absorbs and destroys the vesicant liquids and vapors with which it comes into contact. The present invention covers more particularly the practical processes of using various ingredients and compounds whereby fabrics and clothing having the properties as above described may be obtained.

Such a cloth may be obtained by the use of one of several chemically reactive compounds. These compounds, are preferably fixed on the cloth by means of an inert binder, but in some .cases a binder is not necessary. The compounds and the binder are preferably evenly distributed in the fabric by the use of a volatile solvent which is vaporized from the cloth after impregnation, leaving the impregnating material and binder fixed in the fibers of the cloth.

An effective impregnating material, for the purposes of this invention, must react with mustard gas (bis(beta chlorethyl)sulfide) and other chemical warfare vesicants quickly and completely so that no vesicant vapors can pass through or remain for an appreciable length of time in the impregnated cloth without reacting. Furthermore, the impregnating materials and the binders separately or in combination must of themselves be non-irritating to the skin. In addition to the above, the impregnating materials must be as stable as possible against oxygen, carbon dioxide, sunlight and moderate washing; must have minimum deteriorating effect on the cloth; must be substantially non-flammable; must not make the clothing too heavy, sticky, stifi or hot; the raw materials must be readily available; and the process must be practical and as inexpensive as possible.

Mustard gas, which is one of the most vesicant and widely-used chemical warfare agents, is susceptible to halogenation.

Bearing in mind the various requisites of the impregnating agent, the best halogenating agents have been found to be compounds having one or more halogen atoms usually attached to nitrogen in combination with one or more stabilizing organic radicals. In general, chlorine has been found to be the best member of the halogen family of elements for this purpose and the compounds of the type described containing chlorine are 'known as chloramides. Without attempting to analyze the reactions between mustard gas and the chloramides, it has been found that these compounds are effective impregnating materials due to the presence of active chlotime in the molecule. The chlorine atom attached to the nitrogen has the property of chlorinating mustard gas and rendering it relatively nonvesicant.

Since the destruction of mustard gas is accomplished by active chlorine, the protective power of a chloramide depends to a large extent on the percentage of active chlorine which it contains. Impregnating compounds which have been successfully used in carrying out the present invention are as shown below:

compound in the binder may be obtained for effective impregnation of the fabrics. The impregnating mixture thus made may be a solution of impregnating agent in Percent Name Formula Active Chlorine Aceto 2,4,6-trichlorphenyl chloramide OH3OON(C1) 00112013 12.99 B61120 2,4,6-tr1chlorphenyl ehloramide CgH CON(Cl)CaH2Cl3 10. 59 p-Brombeneo 2,4,6-trichlorphenyl chloramide BTOGU4OON( ODO H C]: 8. 57 Benzo 2,4-d1chlorphenyl chloramide- G Ei Qs aC 2 11. 80 Aceto 2,4-d1ehlorphenyl chloramide CHaOON(C o aC12 14. 87 Stearo 2,4,6-trichlorphenyl ehloramid C11Ha5CON(O e 3 2 7- 1 Paltnito 2,4,6-trichlorphenyl chloramide- I5HSIOON(GDCBHSC]L- 7. 54 Benzene sulfone benzyl chloramide C H SO2N(GDCH2CH 12. 59 2,3,5,G-tetrachlorphenylene bis-aceto chloramide Ca 14(CH3GON l 17. 78 2,5-dichlor 4-phenylene bis-aceto chloramide C5HZOIZ(CH3OONO1)2 21. 50 Mrdrchlor 3-phenylene bis-aceto chloramide CaHzClz CHaCON O1)z 21.50 Terephthal bis-2,4,6-triehlorpheny1 ehloramideu GQH4(OONGICGTT2C]B)2 11.98 Phthal hrs-2,4,6-trichlorphenyl chloramide CtHKCONOICBHZChh 11.98 Bis-2,4,6-tnchlorphenyl chlrurea..- (OaHzOlzNCDg 14. 54 Dibenzene sulfonyl ethylene dichlord m C HSO2NC1CH2OH2NC1SOzCgHg- 17. 33 Phthal-chlorimide C6H4(CO)2NO1 19. 54 Chlorortho benzoic sulfinide C6H4CO(SO2)NC1- 16.30 Quluoue dichlorimine 05H N01); 40. 05 Ohlorsuccinlrnide (CI-I GOhNOI 26. 50 Dibenzoyl ethylene dichlordiamine Cu sCONClCH2 zNC1COCn 6 04 Beuzoyl chlorcarbamide C H CONHOONHOl 17. 86 Dibenzoyl dichlorcarbamide.. (CEHECONC1)2CO- 20. 75 I odobenzene dichloride OgH IOI 25. 83 Halazone COOHC4H4SO2NCl2. 26. 26 Bis(diehlorphenylchlor)urea (C5H3012NCD2OO 16. 98

Of the above, the preferred compounds are 2,4,6-trichlorophenyl acetyl chloramide, 2,4,6-trichlorphenyl benzoyl chloramide, bis dichlorphenyl chlorurea, and bis 2,4,6-trichlorphenyl chlorurea. Considering all factors, bis 2,4,6-trichlorphenyl chlorurea has been found most suitable, as it has the required solubility and is most stable on cloth exposed out of doors.

The preferred chloramides are solids which usually require the use of some binding material to fix them on the cloth as mentioned above. This binder shall have such properties that upon removal of the volatile part of the impregnating mixture, the impregnating material will be caused to adhere so firmly to the cloth that it will not readily be lost by wear or moderate washing; should preferably be a good solvent for mustard gas and other vesicants against which protection is desired in order to thus bring the vesicant into intimate contact with the impregnating material; should be insoluble in water so as to resist leaching action of water and also to lend stability to the impregnating material; should be a solvent for the impregnating material or should carry it in finely divided form; should remain permanently on the cloth without deteriorating it; must not be highly flammable; and must be unreactive with the impregnating material and not subject to chlorination.

Since the destruction of mustard gas and other vesicants depends upon the active chlorine present in the impregnating material, it will be obvious that if the binder is subject to chlorination, the available chlorine in the impregnating material will be used up. This difficulty can be overcome by using a binder which has been adequately chlorinated prior to its use in impregnation, or by the use of a material which is not subject to chlorination.

Many binders may be more or less satisfactorily used such as chlorinated naphthalene (60% chlorine); chlorinated kerosene (59% chlorine); chlorinated coconut oil (21% chlorine); chlorinated stearic acid (30% chlorine); aluminum salts of chlorinated acids of various oils such as cotton seed oil, coconut oil, olive oil, linseed oil, castor oil, China-wood oil; nitrocellulose lacquers; synthetic resins; and chlorinated paraffin. Of these binders, chlorinated parafl'in containing to 52% chlorine is preferred. Most satisfactory results have been obtained using paratfin containing about 42% chlorine.

Most of the compounds listed above are more or less soluble in the binders, above given. If the compound and the binder are heated and simultaneously thoroughly mixed, a sufficiently high percentage of the hinder or it may be partly a solution and partly a finely divided suspension of the agent. The impregnating solution prepared in this manner may be directly used on the fabrics. However, one method of attaining a more uniform distribution of the impregnite and the binder involves the use of a volatile solvent. This latter must be a good solvent for both the agent and the binder; it must be unreactive with the agent; it must not damage the cloth; and it should be non-flammable.

The volatile solvents which more or less satisfactorily meet these requirements are acetylene tetrachloride (tetrachlorethane); chlorobenzene; chloroform; ethylene chloride; trichlorethylene; pentachlorethane; and o-dichlorobenzene. The preferred volatile solvent is acetylene tetrachloride, considering all factors to be met.

As heretofore stated, chlorination of vesicants can be effectively accomplished if a compound having a high content of active chlorine can be permanently fixed to the cloth in such manner that immediate and close contact can be obtained between the vesicant and the compound. In preparing the ingredients for impregnation, approximately equal parts by weight of an impregnating compound selected from the list as given in the table and the binder are mixed with the volatile solvent. The three materials should be carefully and thoroughly agitated until a homogeneous solution is obtained.

Generally, the proportions by percentage are approximately 5 to 12% impregnite, 5 to 12% binder, and 90 to 76% volatile solvent. One specific and preferred embodiment' comprises bis (2,4,6-trichlorphenylchlor)urea 5 to 12%, chlorinated parafiin (containing approximately 42% chlorine) 5 to 12%, and acetylene tetrachloride 90 to 76%. Excellent protection has been obtained in a variety of protective garments and other fabricated articles from various grades and types of fabric using the above mixture; that is, cotton or woolen gloves, breeches, shirts, underwear, socks, leggings, hoods, coveralls, blankets, belts, canvas covers generally, etc.

Different fabrics and garments may require different percentages of impregnating compound and binder to attain sufficient protection under varying conditions of use but satisfactory results are attainable using the above percentages. Practical tests have demonstrated that excellent protection may be attained by using a solution comprising 5 approximately 8.5% impregnite, 6.5% binder, and volatile solvent.

After the above solution has been made, the garments or fabribc are thoroughly soaked therein. Though not essential it-is preferable to have thersolution above atmospheric temperature,"-usuall-y betWeenSS-and 60 C. After soaking for about minutes to insure thorough saturation which may be accompanied by a tumbling or other movement of the articles in the solution, the garments or fabric are wrong out or centrifuged to remove excess solution. Of course, suificient of the solution should be allowed toremainin the garments or fabric to obtain the desired protection. Iftoomuch of thesolution is allowed to remain, air permeability is reduced and the garments are too heavy for comfort. It-has been found that about 20% increase in the weight of the cloth due to impregnation results in adequate protection against vapors of chemical Warfareagents. After the volatile solvent has beenremoved, thisincrease in weight consists of approximately equal parts of impregnating compound and binder 'so that thecompound amounts to about of the original weight.

Next, the garments or fabric are dried:to evaporate the volatile solvent which in the preferred embodiment is acetylene tetrachloride. This may be accomplished by passing a current of.air.over an'dzthronglrithe garments or fabric, or the garments may be merely hung to allow the solvent to evaporate. Preferably, care should be taken that the solvent is evaporated before the garments or fabric are exposed to sun and other strong light, as such exposure tends to discolor the garments or fabric.

This invention has been successfully used in the largescale impregnation of clothing and fabrics by the use of a closed system substantially similar to commercial drycleaning machines and equipment and including solvent recovery equipment. With this equipment the clothing can be completely processed without removal from the machine. When using such equipment, it is preferable to predry the clothing before treatment when using a solvent which tends to hydrolyze. In the preferred embodiment of the invention as above given, using acetylene tetrachloride as the solvent, this preliminary drying is desirable to prevent corrosion of the machine and damage to cotton fabrics by reaction products resulting from hydrolysis of the solvent. The garments or fabric may be dried by any well-known method such as passing a current of heated air over and through them. When using the closed system as above described, this drying may be readily accomplished by passing heated air over and through the garments while they are being tumbled in the drum of the machine. In this type of equipment the volatile solvent may be recovered for reuse.

Treatment of fabrics in accordance with this invention may also be accomplished by a continuous process wherein the fabric in the bolt is impregnated. This type of equipment may include a predryer, a soaking tank, squeeze rolls or vacuum extractor, and a final dryer. Using this equipment, the continuous web of fabric would pass in sequence through the equipment and could then be fabricated into such protective articles as desired.

It will be understood, however, that this invention is not limited to any particular type of equipment or system since adequate protection has and can be obtained by hand methods using open tubs, the garments being stirred in the tub and excess solution being removed by wringmg.

Whether the impregnation of garments and fabrics is carried out with the aid of a volatile solvent or without such solvent, the active impregnating agent should be in a very finely divided state. When a volatile solvent is used and the agent has low solubility in the binder, the agent is held to the fibers of the fabric in the form of finely divided particles. The more finely divided are the particles, the more readily and completely will they react to destroy the vesicants. The physical mechanism of the reaction between the impregnating agent in chlorinated paraifin on the fabric and mustard gas appears to be as follows. The mustard gas vapor dissolves in the chlorinated parafiin and difiuses into contact with the particles of impregnating agent. The chlorination of the mustard the preferred binder, i.e., chlorinated paraffin containing about-42% chlorine, van'dit is-preferred to use a volatile solventto secureleven andthorough impregnation. How- -ever, this low solubility increasesthe stability of the agent on the cloth. Most organic compounds are considerably more susceptible to thevaction of light, air and moisture when in solution'ithan'tinrso'lidlform. Since most of the preferred impregnite is in solid form, it is surrounded by afilmflof chlorinated paratfin whichprotects it from air andimoisture. But since thebinder (chlorinatedparaffin in the preferred embodiment) isa good solvent for the vesicants, the activeimpregnating agent is at once available for reaction with the vesicants.

Thefabrics origarrnentsthatare treated in accordance with this invention are especially useful for protection of military or naval personnel who may be exposed to vesicant chemical warfareagents such as mustard gas. Such garments may also be used by personnel whose duty it is to renovate or decontaminate areas which have been contaminated with such gases. Since mustard gas is very persistent, it is not readily dissipated and therefore it must be removed or rendered harmless by the application of neutralizing chemicals. The personnel employed in this work may be protected by wearing clothing treated as herein described.

Garments rendered protective by our invention are not different in appearance and comfort from untreated garments. Air permeability is not affected enough to make the garments uncomfortable. The weight of the garments is increased slightly but in other respects they are substantially equal to untreated garments. They may be laundered without material loss of effective protection. There is, however, a gradual loss of protective efiiciency after relatively long wear and repeated laundering; but such garments may be re-impregnated to renew their effectiveness.

Such re-impregnation serves to decontaminate clothing which has been rendered toxic by. exposure to chemical warfare agents. Also, the initial impregnation serves to renovate contaminated clothing. The decontaminating action of the compounds herein described is of course not limited to fabrics or garments, since they are also efiioacious on any contaminated articles or materials.

The compounds herein described act to repel and kill lice or other vermin.

While we have described the preferred embodiments of this invention we wish it to be clearly understood that we do not confine ourselves to the precise steps or ingredients set forth herein by way of illustration, as it is apparent that many changes and variations may be made therein by those skilled in the art without departing from the spirit of the invention or exceeding the scope of the appended claims.

We claim:

1. A method of rendering fabrics impermeable to mustard gas and other vesicants susceptible to chlorination while retaining air permeability of the fabric by fixing thereon vesicant destroying chloramids Which consists of mixing a chloramid of the group consisting of and R is a chlor substituted aromatic radical with a. binder of the group consisting of chlorinated naphtha- '7 lene, chlorinated kerosene, chlorinated coconut oil, chlorinated stearic acid and chlorinated paraflin in a volatile solvent from the group consisting of acetylene tetrachloride, chlorobenzene,chloroform, ethylene chloride,

trichloroethylene, pentachlorethane and o-dichloroben- 5 zene, saturating a fabric with the mixture carrying solvent and permitting the solvent to escape from the saturated fabric whereby it is left coated with a chloramide-dispersed binder.

2. A method according to claim 1 wherein the binder is chlorinated paraflin and the solvent is acetylene tetrachloride.

3. A method according to claim 1 wherein the mixture carrying solvent is prepared by mixing 5 to 12 parts by weight of the chloramide with 5 to 12 parts by weight of the binder in 76 to 90 parts by weight of the solvent.

4. A method according to claim 1 wherein the vesicant destroying chloramide is bis(2,4,6,-trichlorphenylchlor) urea.

5. A method according to claim 1 wherein the vesicant destroying chloramide is bis(dichlorphenylchlor) urea.

References Cited in the'fileof this patent UNITED' STATES PATENTS OTHER REFERENCES Chattaway et 'al.:' Berichte der deutschen chemischen Gesellshaft," vol. 34, pages 1073-1078 (1901).

Vedders The Medical Aspects of Chemical Warfare, page 213 (1925). L

Lawson et al.: Jour. Am. Chem. Soc., vol. 49, pages 2119-3125 (1927).

Muntsch: Gasschutz v. Luftschutz, vol. 4, page 20 (1934) (Chemical Abstracts, v01. 28, page 2431 (1934)).

Claims (1)

1. A METHOD OF RENDERING FABRICS IMPERMEABLE TO MUSTARD GAS AND OTHER VESICANTS SUSCEPTIBLE TO CHLORINATION WHILE RETAINING AIR PREMEABILITY OF THE FABRIC BY FIXING THEREON VESICANT DESTROYING CHLORAMIDS WHICH CONSISTS OF MIXING A CHLORAMID OF THE GROUP CONSISTING OF