Patented Feb. 20, 1940 2,190,105 UNITED STATES. PATENT OFFICE 2,190,105 ‘ empress nnmva'nvn mansions Alfred Dreyling, South River, and William W. Lewers, Parlin, N. 1., assignors to E. I. du Pont de Nemours & Company, Wilmington, ml, a corporation of Delaware ‘No Drawing. Application August 15, 1935, Serial No. 86.388 8 Claim!- (CL 106-37) This invention relates to ‘emulsions and more A still further object is the provision of an im particularly cellulose derivative emulsions of the proved process for preparing aqueous cellulose de “high solids” type. It has been recognized that rivative emulsions by low-speed mixing. oil in water emulsions; i. e., those in which water Another object is the provision of a process for 5 is the continuous phase, are the more important preparing improved aqueous derivative emulsions 5 industrially. In the present invention, the col by means of kneading type equipment. _ loided cellulose derivative may be considered the A further object of the invention is the provi- . oil phase and the water the continuous phase of. sion of an aqueous nitrocellulose emulsion which the emulsion. According to the prior art, emul is high in ?lm forming solids and‘ which, if de o sions have been prepared by ?rst colloiding the sired, may contain nitrocellulose of high viscosity nitrocellulose with a high percentage of essen characteristic. tially water immiscible solvents and/or water im A still further object is the provision of aqueous miscible solvent or non-solvent softeners, after cellulose derivative emulsions which are charac which the nitrocellulose colloid is added with terized by good stability. 1 or rapid agitation to the aqueous phase which also It is ?nally an object of the present invention 15 contains a suitable emulsifying agent. The mix to provide aqueous cellulose derivative emulsions ture, may, if desired, be run through a colloid which areindustrlally useful for coating and im mill or homogenizing valve to improve the sta pregnating purposes. bility. These objects are accomplished by kneading a 20 . The nitrocelluloseemulsions of this type here relatively sti? cellulose derivative colloid together 20 tofore available are, however, subject to several with a viscous water colloided emulsifying agent de?ciencies, chief of which is the relatively low to form a paste type oil in water emulsion of high ?lm-forming solids content, thuslimiting their ?lm forming solids content and of good stability. more general industrial adaptation. Satisfactory In its simplest form low speed mixing procedure - 25 stability could not be assured, especially when at- ' consists merely in adding one liquid (the phase to 25 tempts were made to increase the solidscontent. be dispersed) to another liquid (the continuous Frequently, also, excessive amounts of expensive phase) accompanied by relatively gentle agita tion. This method has been suitable only in those solvents were required. I Emulsions have been prepared in several ways, instances where the two liquids emulsify readily 30 such as by homogenization, high speed mixing, or where very e?icient emulsifying agents‘ are 30 and low speed mixing. Because of speci?c limi used. The present invention affords a substantial tations imposed on low speed mixing processes as industrial advance in the art of manufacturing attempted ‘heretofore, high speed and/or homo cellulose derivative emulsions by providing an im'-%' genization methods only have been utilized. proved process for their preparation by .low speedy .: “ 35 High speed processes can only be used for liquids mixing. The new process is essentially a modia, a5 which are relatively mobile at temperatures of ?cation of and an improvement on lowv?speedk; 100° C. or less. Homogenization processes involve mixing methods hitherto available for preparing the use of a colloid mill or homogenization valve emulsions, whereby cellulose derivative emulsions through which the mixture of the constituent in in paste form and of high solids content maybe readily manufactured. , , 40 40 gredients or a preformed emulsion may be passed The following examples are given to illustrate to form an emulsion which is generally charac terized by a product of improved stability. the invention, but it will be understood that they This invention has as an object an improved are not limitative since modi?cations will readily aqueous cellulose derivative emulsion, and a proc occur to those skilled in the art. 45 ess for making the same. Exmrr: 1 . 45 ~ Another object of the invention is the provision Colloid #1 ‘ of a process for preparing aqueous nitrocellulose Per cent emulsions from water wet nitrocellulose. A further object of the invention is the provi Nitrocellulose (viscosity, 15" Hercules)--- 16.85 _ Isobutyl alcohol ______________________ -_ 4.22 50 sion of a process for preparing aqueous nitrocellu " Castor 011 20.00 5° lose emulsions by the use of a viscous water col Tricresyl phosphate __________________ __ 10.53, ‘ loided emulsifying agent. , Butyl acetate _____ __ _________________ __ 11.78 Another object is the provision of a process for Xylol 25.13 preparing aqueous nitrocellulose emulsions which 55 permits the use of a wide variety of emulsifying Colloid #2 _ , 55-, agents which may be utilized in combination with Casein - , ' 1.05 I an emulsifying agent of the water colloided vis-‘ Ammonium ricinoleate _______________ .. 0.84. cous type; for example, “Glutoline,," which is a Water - ' 9.60 1, trade name for a commercial brand of methyl 100.00 60 . s: 17 00 cellulose. - 2 2, 1 90,705 The ammonium ricinoleate contains sufficient tion exists for those examples which follow where excess ammonia to permit the dispersion or the water wet nitrocellulose is used in preparing casein. \The same is true of the succeeding ex Colloid #1. amples in which soap-casein mixtures are used in Exmrr: 3 the formation of an aqueous colloid (emulsifying agent‘). Colloid #1 The butyl acetate ingredient shown in this Per cent example and in those which'follow is 88 to 92% Nitrocellulose (viscosity, 7.3" Hercules) ____ __13.7 ester calculated as normal butyl acetate, the re Water- ____ 6.8 10 mainder being principally normal butyl alcohol. Dlbutyl,‘ phthalate _______________________ __ 8.2 Colloid #1 is prepared by charging the in Isobutyl acetate _ ___ 13.7 10 gredients into a kneading machine such as 9. Tnlunl ______ __13_7 Werner and P?eiderer mixer, in the proportions Colloid #2 indicated and kneading for approximately 11/: Synthetic resin‘ _________________________ __ 10.9 15 Casein __________________________________ __ 1.4 hours or until the nitrocellulose has been uni 15 formly colloided, after which the charge is re Ammonium rincinoleate __________________ __ 0.9 moved from the mixer. Colloid #2 may be Water __________________________________ __30.7 conveniently prepared by means of a rapid agi tator mixer, whereby a homogeneous dispersion 100.00 20 is secured. This intermediate dispersion is then "The synthetic resin used in this example is a reaction 20 charged into a kneading machine and colloid . roduct of phthalic anhydride, castor oil, and lycerol pro ortions designed to yield a ?nished pro not of #1 is added gradually during kneading. This the to owing composition: kneading action is continued for approximately Per cent 2 hours or until a uniform emulsion of paste-like Glyceryl triplifhalnfe 63.0 25 Castor 0" 27.0 consistency has been obtained. Excess glycerol 10.0 25 In this example, the nitrocellulose has Been 100.0 dehydrated with isobutyl alcohol, but suitable and is prepared b heating the ingredients until a com emulsions may also be prepared from nitrocellu paratlvely low acd number (25 or below) is reached. Obviously, many other resins having a su?lciently low loses which have been dehydrated with other acid number so as to prevent the formation of water 30 suitable liquids, such as propyl alcohol, isopropyl colloidable alkaline salts may be substituted for the ex 30 alcohol, etc. Ethyl alcohol may be used, al ample given. though it is not preferred. The isobutyl acetate shown in this example and in those which follow is 88 to 92% ester calcu Exmrnn 2 lated as isobutyl acetate, the remainder being 85 Colloid #1 principally isobutyl alcohol. Per cent The product of this example may be used in Nitrocellulose (viscosity, 15" Hercules) _..___16.85 ?nishing wood surfaces. Water 7.22 The emulsion is prepared in the same manner Castor oil ' 20 00 as shown for Example 2. 40 Tricresyl phosphate _______________ _._. ____ __10.53 Butyl acetate 11 78 Exsmrrr: 4 40 Xylol 25.13 Colloid ‘#1 Collm'd #2 ' - Per cent Casein 1.05 Nitrocellulose (viscosity, 7.8" Hercules) ____ ._14.45 45 Potassium rincinoleate __________________ __ 0.84 Water _ 7.25 Water 6.60 Dibutyl phthalate ______________________ __ 8.70 Butyl a’cetate __________________________ __ 14.45 100.00 'I'olunl _14.45 The ingredients of Colloid #1 are charged into Colloid #2 a kneading machine and kneaded until a smooth Synthetic resin‘ ________________________ _..11.55 paste is obtained. Colloid #2 which is pre Locust bean gum _______________________ __ 0.35 pared separately in a suitable rapid agitator mixer Water > a 28 75 is then added slowly to Colloid #1 in the knead Ammonia (28%) _____ __‘_-__; ___________ __ .05 ing machine and kneading continued for about 1%; hours or until a smooth uniform emulsion 100.00 paste is produced. ‘The synthetic resin and its preparation in this ex This example represents a modi?cation of Ex ample is the same as shown in Example 3. The com pos tion may be utilized in ?nishing wood surfaces or as ample 1 and differs therefrom essentially in the a thermoplastic adhesive. use of water wet nitrocellulose in preparing 60 Colloid #1. This is of particular advantage Exmns 5 60 in that the customary step of dehydrating the Colloid #1 nitrocellulose is eliminated, thereby affording , .