US2183587A

US2183587A - Exothermic mtxtuke

Info

Publication number: US2183587A
Authority: US
Publication date: 1939-12-19
Anticipated expiration: 1956-12-19

Description

Patented Dec. 19, 1939 UNITED s'rarss PATENT QFFICE EXOTHERRIIO MIXTURE tion of Missouri No Drawing. Application December 4, 1936,

' Serial No. 114,204

16 Claims.

This invention relates to an exothermic chemical composition which, when moistened with water, or aqueous liquid, spontaneously evolves a controllable quantity of heat and may be used in pads or envelopes of suitable construction for various purposes, such as thrrapeutic heating pads, hair-waving heating pads, and the like.

The heat evolving properties of the chemical composition depend upon the principle of oxidation-reduction which is known to be a highly exothermic chemical process, and which is set in action by the moistening of the chemical composition with the liquid. Under certain operating conditions it is essential that the reactions conform closely to well defined requirements in order that best results be secured. For example, in a hair waving pad when the mixture is moistened the resulting temperature should rise to the boiling point of the liquid in from thirty seconds to three minutes, and this temperature should be sustained for about five minutes and then increased about 2 to 10 C. in one to three minutes, and thereafter drop quite rapidly to about 50 C. when the pad may be handled by the operator without discomfort.

It is necessary that the water vapor evolved during the active heating period of the composi tion be emitted slowly and gently to avoid burning the scalp by strong jets of steam. It is also necessary that the composition be of a stable character. so that pads several months old will 'commence heating within two or three minutes after moistening.

The objects of the invention are to fulfill the above mentioned requirements and to avoid the disadvantages expressed or implied.

The composition consists primarily of a mixture of metals with other ingredients which in the presence of water aid in the oxidation of the metallic mixture. Aluminum is to be preferred as the principal metallic ingredient because of its cheapness, convenience, and the high heat of formation of its compounds'although iron, magnesium, zinc, cadmium and other metals may be used. In practice it is found that the composition is improved by the use of a secondary metal, positioned lower in the electromotive series of metals, such as copper, zinc, tin, bismuth,'antimony, lead, mercury, arsenic, and active alloys of the same containing sufllcient of the named metal to be substantially as active as the named metal. The purpose of these metals is to supply heat by means of their oxidation. We have found that the duration the heating period may be (Cl. HF-3) oxidizingdecomposition products which are formed when it is acidified, potassium chlorate is one of the most convenient oxidizing agents to use.

We find that the proportion of this ingredient has a pronounced eiIect upon the course of the heating period. particularly in determining the point oi rise above the boiling temperature of water and the rate of final cooling.

An acidic substance which produces an d by hydrolysis, and which contains a metal chplaceable by the principal metal reducing agent, serves not only to act as a source of acid to decompose the oxidizing agent but also to supply quickly available heat by means of a displacement reaction. The proportion and properties of this ingredient regulates the time necessary to reach the boiling temperature of water. This substance may be cupric sulfate, cupric nitrate, cuprous chloride, cupric iormate, cupric tartr'ate, cupric chlorate, cupric lactate, eupricsalicylate, cupric sulflte. cupric-phosphate, cupric acetate, cuprous bromide, cuprous sulilte, cuprous iodide, cuprous ammonium iodide, and the corresponding salts of iron, cobalt, nickel, tin, bismuth, mercury, arsenic, antimony, and lead. However, it is foundthat 85 greater stability of the composition will result if the salts of relatively low solubility such as cuprous chloride and cupric tartrato are selected.

In place of the above named source of an acidic media which produces a preponderance of hydrow gen ions, certain soluble solid organic acids may be used and their very slight tendency to absorb water from the atmospil -.."e helps minimize undesirable decomposition of the ingredients due to the absorption of moisture from the atmosphere. 5

Another advantage of the weak solid organic acids is that their partial wetting by means of small amounts of water in the surrounding atmosphere has less corrosive and deleterious eflectn on the other ingredients, whereas the hydrolysis of acidic inorganic salts like cuprous chloride may result in the formation of strong mineral acids which attack other active insrodients of the mixture. Acidic substances which may be used for this purpose are oxalic acid, tartaric acid, adipic acid, '5

benzoic acid, cinnamic acid, isocinnamlc acid, uric acid, maleic acid, oxamic acid, pimelic acid, phthalic acid, phthalic anhydride, salicylic acid, tannic acid, tolulc acid, and the like. The lunctioning of the acid or mixture of acids in the mixture is round to depend upon the polarity, solubility, and neutral equivalent, all of which are closely related as far as this problem is concerned. For example, an exothermic mixture containing benzoic acid, which is an acid of lower water solubility, higher neutral equivalent and lower polarity than tartaric acid, will require longer to attain the boiling temperature of water than one containing the latter acid in the same proportion.

The above indicates the nature and specific embodiments of the essential ingredients in the composition. Others may be added to control the evolution of heat, increase the shell life of the finished product, for economy, or for some other reason.

Certain oxides lilre cuprous and cupric oxides appear to be valuble addition agents because they accelerate the evolution of heat, evidently by means by replacement reactions. Such oxides are, however, notessential components.

An additional function or such elements. is to stabilize the mixture because they are relatively inert when subjected to atmospheric moisture only, although becoming active when combining with the acidic media produced by the addition of a substantial quantity of water to the mixture.

The addition of a small proportion oi mineral oil is beneficial in retarding the speed of chemical action when the boiling temperature oi water is reached, and in increasing protection from atmospheric deterioration. The oil appears to lorm a thin protective illm over the gradients, thereby slowing down the evolution oi water vapor. The so-called drying oils such as linseed and China-wood oils are very eflectlve, and in addition they aid the stability 01 the cornpomtion probably by the removal of tree oxygen from the atmosphere and occluded on the surrace 01 they active ingredients.

Certain desiccatlnz agents, such as calcium sullate or magnesium carbonate, may be added to preserve the dryness oi the packaged mixture. This is also aided by preliminary oven-drying o! the mixture bdorc packins.

As a diluent tor the active ingredients, to aid in protecting the active ingredients from the deleterious eiiects .31 the atmosphere, to reduce the cost of the composition. and to aid in securin: the proper quantity 01 heat irom-each pad, we may use pumice, kaolin, kiesclguhr, silica, chalk, calcium sulfate, gypsum, or any other cheap chemically inert material.

Tho iollowinu is an.examplc o! a composition which we and to be satisfactory:

Grams Pumice 6.0 Kaolin 4.0 Aluminum 3.0 Brass 2.0 Potassium chlorate 1.5-, Ouprous oxide 0.2 Cuprcos chlor 0.6 Linseed nfl 0.2 Magnesium carbonate 0.1 Itwillboporooivcdthot the mop rtionsottho ina'edicnts may be quite widely varied to obtain variousshspcsotcoolinscurves. Anexplanation olthe chemical reactions whi tahcplacewhcnsuchamixtureismoistonodwith m is ted by the simul occursurtace of the inrence of several reactions and by the intcrdepend- Ou2Ch 23 0 --o 0:1,(013), 280i Ouprous water on rous hydrochloric chloride by side acid $011.10]; 2A1 -0 2Al0ll OOn Curpous aluminum aluminum copper chloride chloride BOT H Cl- Hydrochloric hydroesn chlorine ions "sold ions H K0101 H010; K Hydrogen potassium chlori potassium ion s chlorate acid ions AlOh 33.0 AKOH); and] Aluminum water aluminum hydrochloric chl0rld0 hydroxide add Cmo 21101 CusCls H1O Ouprous hydrochloric cu rous water oxide Orido 3301 Al AlOh 3H Hydrochloric aluminum aluminum hydrous acid 4 chloride 23010, E10 201 Ohlorlc sold water chlorine omen 0 par 0 a cup 0 p chloride as 201 ---t 21101; Zinc chlorine sins chloride .u 301 ------o' AlOh Aluminum chlorine 4 um chloride ZnOh 21110 --v Zngflh 2K0] zinc chloride m o hydrochloric hydroxide acid ovoil mg 0535). .mm

o s o ydrochlorio nd: hy oxi e odd SZnOh RAl' 2Al01; I m Zinc chloride aluminum aluminum Zine chlorido 26inch m M nich son. uprlo nmi-n nmlnnm copper chloride chloride nu o --o m0 Hydrogen own new Undoubtedly other equations expressing possible reactions could be written, although the above are sumclent to account for the behavior or the composition when moistened. It will be seen that the malority of them enrolls oxidationreduction or t reactions, both of which are known to be hiahly exothermic.

Itwillbeunderstoodthattheexampleoia satisfactory composition upon which the torngoin: equations are based suucsts quantities which may be varied substantially in some instances without noticeable choose in results and.

in other instances with chances which may be considered advantageous accordin: to the degrees of heat produced and the timopsriodsovcr which production or hcatis extend As suucstivsot suchvariationsin quantities, itlsnotcd that the inortdllwsntmayvaryi'rombtommms, aluminum from i to 0 grams. the brass mobmllmmathepotassiumchlontetrommi tobmmathccuprousoxideirommwtoe mmathocuprouschloridetrom02to4uams. Aspreviously indicated. the mincrlloilandmsancsium temaybeclimlnnted entirely usedlnquantitiesasstatedorsubstmtiallylsner according to the mass of the other ingredients involved.

As an example of an exothermic mix utilizing organic acid as a source of the acidic media, the

following has proved satisfactory, although neither the specific ingredients named nor the proportions given need be adhered to in view the earlier references to equivalents:

' Grams Brass 2 0 Pumice 6 0 Kaolin 4 0 Aluminum 3.3 Cuprous oxide 0. Salicylic acid 0.8 Raw China-wood oil 0.1 Potassium chlorate 2.4 Magnesium carbonate 0.1 The above mixture when moistened with water, produces substantially simultaneously a number of reactions, many of which are interdependent upon each other. The most essential, although not necessarily all of the resulting actions, may be summarized by the following equations, the majority of which express oxidation-reduction or displacement reactions, both of which are known to be highly exothermic:

I OH on Gi H +CaH1\ COOH 000- Balicyllc acid hydrogen saiicylate ion (in solution) ions 11+ X010} -9 H010, Kt Hydrogen ion potassium chloric acid potassium chlorate ion 211010, E10 2C l so Ohloric acid water chlorine oxygen Al 301 --i A191, Aluminum chlorine alummum chloride Cu 201 cuoi, Copper chlorine cupric chloride 2 201 -t 21101, Zific chlorine zinc chloride AlCh I'iHaO AKOH): 3HC1 Aluminum water aluminum hydrochloric chloride hydroxide acid cmo 2H0] Gulch H10 Cuprous hydrochloric cuprous water oxide acid chloride a1 3301 -i x1c11 an Aluminum hydrochloric alumunim hydrogen acid chloride 2A1 search 2x101. 60c Aluminum cuprous aluminum copper chloride chloride 201 01110]! --i fICuCl; Chlorine on tons cupric c orido chloride 213,0 011,01. oul(0H 2301 Water on tons on rent hydrochloric oh orido hy roxide acid ouch 21110 cumin. 21101 Cuprio water cupric hydrochloric hlo ide hydroxide acid 01, 2A1 ---i 2x101. 3Cu Cupric aluminum aluminum 0 chloride chloride It is obvious that numerous combinations of ingredients mentioned could be selected from the data given herein and the quantities varied to give different results as to extent and degree of heating. All such compositions are considered as embodying the present invention when they are characterized by the presence of a metal and by the production of hydrogen or hydrogen ions or hydrochloric acid by the addition or water to an otherwise inert mass, to combine with an oxidizing agent and a substance which in an acidic media will furnish metallic ions replaceable by said metal. The mixtures may comprise two metals of higher and lower electrolytic activity, respectively, and a source of acidic media of lower electrolytic activity than the metal having the hlgher electrode potential, or the mixture may include but a single metal and the acidic media may be supplied by an aqueous solution or an organic acid;

Numerous examples oi such modifications are indicated by the variations referred to in the second paragraph following the equations based upon the first ,iormula given herein and by the reference to similar variations relative to the second formula. The exclusive use of these and other modifications of the invention as described in the accompanying claims s contemplated:

What is claimed is: v

1. A composition for producing heat by chemical action, comprising a mixture of a primary metal and a secondary metal, said primary metal being from the group or stable metals positioned above the secondary metal in the electromotive series of metals,-said secondary metal being from the group of stable metals no more active than zinc and active alloys thereof, a substance stable in a dry state and capable when in solution of furnishing an acidic medium, and an oxidizing agent sufiiciently active in the acidic medium and in quantity sufiicient to oxidize both said primary and said secondary metal.

i 2. A composition as described in claim 1 in which the primary metal is selected from' the group consisting of magnesium, aluminum, manganese, cadmium, zinc and active alloys of the same. 1

3. A composition as described in claim 1 in which the secondary metal is selected from the group consisting of zinc, copper, tin, bismuth, antimony, lead, mercury, arsenic, and active alloys of the same.

4. A composition as described in claim 1 in which the primary metal is selected from the group consisting of magnesium, aluminum, manganese, cadmium, zinc, and active alloys of the same, and the secondary metal is selected from the group consisting of zinc, copper, tin, bismuth, antimony, lead, mercury, arsenic, and active alloys of the same.

5. A composition as described in claim 1 in which the substance furnishing the acidic medium is selected from the group consisting of cupric sulfate, cupric nitrate, cuprous chloride, cupric iormate, cupric tartrate, cupric lactate, cupric salicylate, cupric sulfite, cupric phosphate; cupric acetate, cuprous bromide, cuprous sulflte, cuprous iodide, cuprous ammonium iodide, and the corresponding salts of iron, cobalt, nickel, bismuth, mercury, tin and lead, oxalic acid, tartaric acid, adiplc acid, benzoic acid, oirmamic acid, isocinnamic acid, uric acid, maleic acid, oxamic acid, pimelic acid, phthalic acid, phthaiic anhydride, salicylic .acid, tannic acid. and toluic acid.

6. A composition as described in claim 1 in which the oxidizing agent is selected from the group consisting of potassium chlorate, ammonium persuliatc, sodium perborate and peroxide.

7. A composition as described in claim '1 which includes an additional ingredient insoluble in water and normally inert under atmospheric condltions and stabilizing the mixture but being ren-.

' o secondary metsl, said primary metal being from a group of stable metals positioned above the secondary. metal in the electromotive series of metals, said secondary metal being from the group of stable metals no more active than zinc andsctive 'ulioys thereoi. an acidic salt of a metal of lower electrolytic activity than the first of said metals,

and an oxidizing agent sumciently active in the acidic medium and in quantity suilicient to oxidiz'e both said primary metal and said secondary metal and reacting more readily with said primary metal than with the secondary metal.

9. An exothermic mixture comprising a substantial quantity oi. each of a primary metal and a. secondary metal, said-primary metal beins from a group 0! stable metals pomtioned above the. secondary metal in the electromotive series of metals, said secondary metal being from the group oi stsble metals no more active than zinc and active 1 0.85 thereof, an acidic salt of a metal of lower electrolytic activity than the first 0! said metals, and an oxidizing agent selected irom the group of potassium chloratmsmmonium persulfate, sodium perborste and barium peroxide.

10. An exothermic mixture including an inert diluent, aluminum, potassium chlorate, cuprous chloride, and brass.

amass? 11-. An exothermic mixture including the following ingredients in the proportion indicated- Grams Inert diluent "approximately" 5 to 20 Aluminum do ..1 to 6 Potassium chlorate do..- ,0:( to 5 Cuprous chloride do 0.2 to 4 Bruits "do..-" 0.05 to 5 12. [in exothermic mixture including an inert diluent, aluminum, potassium chlorate, cuprous' chloride, brass, and cuprous oxide.

13. An exothermic mixture including the X01- lowing ingredients in the proportion indicated- 14. An exothermic mixture comprising an inert diluent. aluminum. brass. potassium chlorate, cu-

prous oxide, cuprous chloride, linseed oil, and

magnesium carbonate.

15. An exothermic mixture comprising an inert diluent, approximately 10 parts by weight; aluminum. approximately 3 parts; brass. approximstely 2 parts; potassimn chlorate. approximately 1.5 parts; cuprous oxide, approximately-0.2 part7 cuprous chloride, approximately 0.6 part; minersl oil, approximately 02 part; and magnesium carbonate, approximately 0.2 part. i 16. An exothermic mixture comprising an inert diluent, aluminum, brass, potassium chlorate, salicylic acid. cuprous chloride, drying oil, and magnesium carbonate.

mnmmn RACEN. WALTER M. BRUNER.