Патент USA US2404698код для вставки
2,404,698 Patented July 23, 1946 wrap STATE/S PATENT orricc 2,404,898 ' INSECT BEPEILENT COMPOSITION Alfred Dreyling, South River, N. 3., assignor to E. I. du Pont de Nemours & Company, Wll- - mlngton, Del, a corporation of Delaware No Drawing. Application January 4, 1945, Serial No. 571,357 " 10 Claims.’ (Cl. 167-30) 1 . 2 - since only the amount required needbe applied This invention relates to improved insect re pellents and more particularly to insect repellent thus distinguishing favorably from liquid re pellent where'there is greater wastage due to‘ the application of excess material. A further ob Insect repellent compositions presently avail able are widely used with considerable e?‘ective GI iect is the provision of a jelly-like insect repellent which a?’ords greater ease of application and 'ness, especially in combating. various types of which is readily removed by washing with soap mosquitoes. Great quantities ‘of these materials 1 and water. A further object is the provision of are used by the armed forces operating in trop insect repellents which are stable for extended ical. zones where mosquito control is particularly imperative. These compositions are generally storage periods and atslow and high tempera tures. A still further object is the provision of employed in liquid form. In this fonn, how insect repellent compositions which may be pack ‘ever, they are characterized by a serious defect aged in durable containers such as collapsible in that the period of eiiectiveness is too short. tubes thereby avoiding breakage during shipping ' Ordinarily the liquid repellent compositions are effective vi’or less than 3 hours. Application, han 15 and storage handling, such as encountered with a" and shipping, wastage and undesirable glass containers as generally used with liquid repellents.v Other objects will appear as the de stickiness also suggest the need for improve scription of the invention proceeds. ments in such products. Attempts have been These objects are accomplished in accordance made to prolong the effective period by additive edients designed to retard the volatilization with the present invention by means of a com position of jelly-like consistency comprising‘ at rate of the active repellent components. Partial least one component repellent to insects and a success as been achieved by preparing the com plurality of at least partially immiscible cellu positions as emulsions or gels which may include, water soluble colloids such asvgum tragacanth, lose derivatives, selected from the group consist waxes, oils and cellulose esters. However, pre 25 ing of cellulose esters, and cellulose ethers. vious products of this type are objectionable be The follo examples are given by way of cause of the large amounts of additive ingredi illustration only and no limitations are intended ents required to form gels and because of ap thereby except as indicated in the appended pearance, excessive dirt collection, stickiness, claims. ‘ oiliness, or instability during extended storage or 30 Example 1 at high temperatures where there is a tendency ' . . Per cent by weight to liduefy or at low temperatures where there may Ethyl cellulose _________________________ __ 2.7 be a tendency to crystallize. composition 01’ jelly-like consistency. - This invention has as an object the provision of . an improved insect repellent of jelly-like con sistency. . Another object is the provision of an ‘ Cellulose acetobutyrate _________________ __ 2.3 Proplyene glycol monostearate___________ __ 2.0 Dimethyl phthalate ____________________ _- 55.8 2-ethyl hexane-1,3-dioi (Rutgers 612) ____ __ 18.6 insect repellent Jelly which does not cause the Indalone 1 18.6 skin to draw or stiffen Another object of the invention is the provision of an improved insect repellent which is characterized by e?ectiveness 40 1 Alpha, alpha dimethyl alpha carbobutoxydlhydro vfor prolonged periods of time. Another object "1563 is the provision of an insect repellent jelly which . is non-irritating to the skin. Another object is the provision of an improved insect repellent \ composition which permits the use of minimum amounts of additive non-repellent components, thus a?ording maximum protection against in sect attacks. A iurther object is the provision of an insect repellent composition of smooth, gamma pyrone prepared by condensing‘ butyl oxalate with mesityl oxide. The ethyl cellulose used in this composition had a viscosity of 40,000v cps. determined in 5% concentration in a solvent vehicle consisting of 80 parts of toluene and 20 parts or ethyl alcohol. The ethoxyl content of the ethyl cellulose was 46.8 to 48.5%. . and clothing with resultant unsightly marring The viscosity of a 20% solution of the cellulose acetobutyrate dissolved in acetone was about 38" determined in accordance with A. S. T. M. pro and in the case of some fabrics, a partial destruc tion. A further object is the provision of an im cedure D-301-33. 2500 centipoises. Y, jelly-like consistency which eliminates accidental 50 , spilling (as in the case of liquids) on furniture proved insect repellent jelly which avoids waste 55 This corresponds to about The composition was prepared by charging the -.$ 2,404,090 ingredients intoa paddle type mixer and agitat speci?cations D-301-83. ing until a homogeneous mixture was secured. about 34,400 centipoises. ' ' This product likewise, exhibited properties sim The resulting composition had a smooth jelly like consistency. Its mosquito repelling proper ilar to those described for Example 1. ties were satisfactory and it was found that its effectiveness in this respect was more than dou bled in time as compared to the conventional ' “Example 5 __. . vliquid repellent containing the same active in gredients. This corresponds to .. . .. Percent by weight Ethyl cellulose ____ _-__ _________________ _- Also it was observed that a lighter 3.0 . Cellulou acetate .._‘. ____________________ __ l 2.5 application could be used and that the objection 10 Propylene glycol di-stearate ____________ _.~v 0.5 Dimethyl phthalate __________________ _..'_. 56.4 able oily condition common to the liquid repellent z-ethyl hexane-1,3-diol____________ -_'.'.___ 18.8 was eliminated in the new product. Further ' l’ndalnne _ 18,8 more, due to the discontinuous nature of the ap plied ?lm as provided through the use of the two 100.0 incompatible “or immiscible cellulose derivatives, 15 there was no drawing or sti?ening oi’ the skin. The ethyl cellulose used in this composition was of the same type as described in Example 1 Example 2' and the cellulose acetate of the type described ‘Percent by weight Ethyl cellulose ______________ -1 ________ __ 3.2 Cellulose acetobutyrate in-“ _________ __ Dimethyl phthalate ____________________ __ 2.8 58.4 2-ethyl hexane-1,3-diol (Rutgers 612) _____ 18.8 Indalone ____________ _; ________________ __ ‘18.8 . °1oo.o It will be noted that this composition is simi ' lar to Example 1, except that the propylene gly col monostearate has been omitted. The resulting‘ properties are also similar to Ex ample 1 and exhibit comparable superiority in the essential features including prolonged effec tiveness after application to the skin. Example 3 in Example 4. 20 s The product 01' this example also airorded the desired properties previously described. ' In addition to the cellulose derivatives‘dis closed in the preceding examples, other cellulose esters, mixed esters or ethers such as cellulose acetopropionate and benzyl cellulose which are soluble in organic solvents may also be used, pro vided there is substantial incompatibility or im miscibility between the cellulose derivatives, 9., condition which represents a basic requirement 30 for the success of the present invention. In gen eral, it is. preferred to employ two cellulose de rivatives which are substantially incompatible or immiscible in the ?nal ?lm and to use such ma terials in approximately equal amounts. This 35 proportion may be varied considerably but it ’ Percent by weight Ethyl cellulose ________________________ __ 3.0 Cellulose nitrate ___" _________ _... ________ __ 3.0 Dimethyl phthalate ___________________ __ 2-ethyl hexane-1,3-diol ________________ __ Indalone ____________________________ __'__ 56.4 18.8 18.8 must be maintained in such relationship that a final ?lm which is discontinuous in character will result. The viscosity characteristic of the cellulose de 40 rivatives used in the products of the invention is important. It is necessary that only high vis cosity types be employed to a?’ord the desired consistency in the ?nal product and maintain 100.0 the maximum initial e?'ectiveness in repellent The ethyl cellulose used in this composition 45 action by including only the minimum in non-ac tive ingredients. In Example 1‘, it is shown that was of the same type as that described in Ex a cellulose acetobutyrate with a viscosity char _ acteristic ofabout 2500 centipoises determined The cellulose nitrate had a nitrogen content in a 20% solution in acetone may be used satis of about 12% and a viscosity characteristic 'of 887 seconds determined in accordance with the 50 factorily. However, in‘ order to meet the basic conditions of proper consistency in the ?nal procedure described in A. S. T. M. Spec. D-301-33. ample 1. Formula A. This corresponds to about 330,000 centipoises. ' - product combined with low non-repellent ingre dient content, it is necessary when using one cel lulose derivative oi’ this relatively low viscosity This product exhibited properties similar to 55 characteristic‘to include as the other cellulose " ' those described for Example 1. derivative one which has a much higher viscos Example 4 r ' Percent by weight Cellulose acetate ______________________ __ 2.5 Cellulose nitrate ______________________ __ Glyceryl di-stearate _______________ _______ ‘3.0 0.5 Dimethyl phthalate _______ -3. ___________ __ 58.4 2-ethyl hexane-1,3-dio1 ________________ _- 18.8 Indalone____; _______ ___ _______________ -c- 18.8 100.0 The cellulose nitrate used in this composition was of the same type as that described in Ex ity characteristic such as suggested" in Example 1 where the second cellulose derivative is ethyl cel lulose with a viscosity many times higher than 00 that 01' the cellulose acetobutyrate. In general, the combined cellulose derivative content should be about 5 to 6% by weight of the total composition. The preferred viscosity of the ?nal product is about’ 300,000 centipoises al though suitable compositions may be prepared with viscosities between about 200,000 and 500,000 centipoises. The total cellulose derivative con tent may be' varied preferably from about 1% to 10% by weight of the total composition depend 70 ing upon the viscosity characteristic oi! the cel The cellulose acetate had a combined acetic lulose derivatives. Thus if dynamite type cellu acid content of about 55% and a viscosity of lose ni-trate which has a very high viscosity char ample 3. ' about 100 seconds determined on a 20% concen acteristic is used, the amount of cellulose deriva tration of the cellulose acetate in acetone and _ using the procedure described in A. S. T. M tive may be as little as about 1% and still main tain the desired gel-like consistency. The proper 2,404,698 6 - '~ more than double that or the conventional liquid type insect repellents. The improved gel-like re.‘ pellents are distinguished by ease oi application, consistency may likewise be maintained with amounts of cellulose derivatives as high as about 25% with proper adjustment in the use of the reduction in greasy feel and avoidance 01' wastage lower viscosity material. The higher concentra tions of cellulose derivatives tend to reduce the 5 since no excess is applied as in the case of the liquid products. Problems of spillage, handling overall repellent eilectiveness and it is therefore and storage such as encountered with liquid preferred to employ concentrations of cellulose products which are frequently packaged in glass derivatives of not over about 6% for most pur containers are avoided in the new composition poses. _ since collapsible metal tubes are satisfactory con The examples include three components hav tamers. Marrmg of furniture and destruction of ing insect repellent properties since this combi certain fabrics wnichare attacked by some repel nation (dimethyl phthalate “Rutgers 612” and lent ingredients through accidental spilling are “Indalone" in the ratio of 3:1:1) has already avoided with the compositions of the present in demonstrated its effectiveness in the ?eld, par The improved repellents are stable at ticularly as a mosquito repellent. ‘However, for 15 vention. high or low temperatures for extended storage some purposes, this ratio may be varied consid-‘ periods and do not crystallize or 'liquei'y at tem erably or only one or if desired two of these com perature extremes. They are readily removed by ponents may be employed. For example, di washing with soap and water. methyl phthalate has proven to be quite useful It is apparent that many widely different em 20 as a repellent and may be substituted wholly for bodiiments or the invention may be made without the other repellent components. Also, other ma departing from the spirit and scope thereof; and, terials haying properties repellent to insects may therefore, it is not intended to be limltedvexcept be substituted for or used in conjunction with the’ as indicated in the appended claims. repellent components previously suggested. In the examples, the cellulose derivatives are soluble in at least one of the repellent compo ‘as nents, particularly the dimethyl phthalate and consequently when agitated in this described medium become colloided toform the jelly-like I claim: - 1. A non-aqueous insect repellent composition of gel-like consistency substantially free from highly volatile solvents comprising a plurality of cellulose derivatives selected from the group cone sistmg of cellulose esters and cellulose ethers and consistency described. The addition of other 80 at lea-st one non-volatile insect repellent which is solvents which may if desired be of the more vol a solvent for the cellulose derivatives separately, atile type is not precluded since the'invention is operable under such conditions provided the amount of added solvent does not destroy the de; the said cellulose derivatives being incompatible when combined in the said repellent whereby a consistency is obtained. sired jelly-like consistency and provided also that 35 gel-like 2. Thecomposltion of claim 1 in which the cel ' the solvent added does not destroy the incompat- . lulose derivatives are ethyl cellulose and cellulose ibility or the cellulose derivatives. Some of the preceding examples provide for the use of glyceryl di-stearate or ‘propylene glycol acetobutyrate. , 3. The composition or claim_ 1 in which the insect repellent is dimethyl phthalate. di-stearate. The use of these ingredients is on 40 ' ‘l. The composition of claim 1 in which one of tional but they are of advantage in rendering the composition more easily removed by washing _ the cellulose derivatives is ethyl cellulose and the other is a cellulose ester. . with soap and water. Furthermore, they con 5. The composition or claim 1 in which the tribute somewhat in reducing the objectionable ?nal viscosity is between 200,000 and 500,000 cen greasy appearance caused by certain of the re tipoises. . pellent components. 1 6. The composition of claim 1 in which the cel The products of the invention are generally lulose derivatives are present in an amount be useful for application to exposed portions of the tween about 1%, and 10% by weight of the total skin for the purpose or repelling insects and ‘ more particularly various types of mosquitoes. 50 composition. '1. The composition of claim 1 in which the’ Thus the compositions ?nd particular utility in cellulose derivatives are present-in an amount of tropics especially in the armed forces stationed about 6% by weight of the total composition. in such areas under circumstances where there is very little or no other protection against mos quitoes. . 8. The composition or claim 1 in which the cel 55 lulose derivatives consist or ethyl cellulose and a siellulose ester in approximately equal propor The unique results obtained in the improved ons. products as afforded largely through the discon 9. An insect repellent composition or gel-like tinuous nature of the applied ?lm may be attrib consistency comprising dimethyl phthalate, 2 uted to the combination of a plurality of cellu ethyl hexane-1,3-diol, Indalone, ethyl cellulose, 60 lose derivatives which are at least partially in cellulose‘ acetobutyrate and propylene slycol compatible or immiscible with each other in the ?nal ?lm thus providing discontinuity. This 10. An insect repellent composition of gel-like combination also contributes to the “shortness” consistency having the following composition by monostearate. of the gel thus improving application‘ properties. The gel-like structure of the cellulose derivative colloids function to retard volatillzation of the active repellent components thereby markedly prolonging the effectiveness of the insect repel lent properties. The new compositions are characterized by 70 numerous important advantages chief of which is the desired prolongation of the e?ectiveness ai'ter application of the repellent activity which bee by the present invention been extended to - ' weight: ‘ Percent Ethyl cellulose 2.7 Cellulose, acetobutyrate ............. --..-..- 2.3 Propylene glycol monostearate .......... ..- 2.0 Dimethyl phthalate ................... .... 55.8 2-ethyl hexane-1,3-diol. ...... --.._..--....--.. 18.6 Indalone ' - I 18.6 ALFRED DREYHNG.