US2161747A - Inhiriting of foaming in systems containing gelatine - Google Patents

Description

Patented June 6,1939

G F FOABIING 1N CONTAINING GELAIINE Maurice L. Piker and stephen 0. Pool,

N. Y, to Eastman Kodak Company, Rochester, N. Y, a corporation of New Jersey Serial No. 153,686

No Drawing. Application July 14,1931,

8 Claims. (Cl. 252-1) This application relates to the prevention of foaming and trothingin asystem containing gelatine, particularly in the comminution of scrap film by employing a liquid lower fatty acid ester 5 of a monohydroxy aliphatic alcohol of 6-8 carbon atoms. L

In the working up of scrap emulsion coated film to recover the cellulose ester and the therefrom, it is customary to first subject it to a 10 mechanical comminution in the presence of water to render it moresusceptible to the treat-' ments given and to facilitate handling. Foaming chopping operation, especially in warm weather, when the geiatine emulsion is more susceptible to the action of the warmer water which is present duringthe chopping operation. This foaming and frothing reducesthe capacity of the containers in which the chopping is carried out, oftengo. limes causes overflowing. thereof, and may even require the cmtion of the operation, prevents observing of the progress of the comminution and, due to the lightnes of the froth, some of it may bethrownfromthevmllnwhichthe chop- 25 Ding or taks places One object of our invention is to provide a method whereby the f and frothing of a.

fluid mass containing gelatlne, such as a.wet massofscrapfihmisprevented. Another-object 30 of our invention isto'provide a method of com- -minutingfilminwhichthefihnisnotadversely afiected andinwhich tone conditionsareabsent'. We have found thatthe-liquidlowerfattyacid estersofthemon alcoholsof formatiom. We have found that as little as .03 lb;

50 oftheseesters per 100 lbsoffihnscrapissuficient I to prevent foaming, although in' practice the use of alittlemore estensu'chas A15 or .06 lb.,is'

preferred. Examples of compounds of this class,

which are useful forthis purpoga and which can 5 he obtained commercially at l price, are octyl 'inanesterwhichisasoiid. or frothing is an objectionable feature of this acetate, such as 2-ethyl hexyl acetate, and secondary hexyl acetate Other liquid lower fatty acid esters of the hexyl, heptyl and octyl alcohols might be employed, particularly if the price makes their use practical on a commercial scale. 5 Although the acetic acid ester of these alcohols is ordinarily prepared and, therefore, would probably be used, nevertheless, other fatty acid esters, such as the propionates, butyrates, etc., may be employedproviding, of course, that the acid is .10 not so high a homologue of acetic acid to result Our inveniaon is adapted both to the processes for recovering nitrate film scrap and that prepared from organic acid esters of cellulose. It is 15 particularly adapted, however, to the recovery of cellultse nitrate from film employing nitrate as the base, as the comminution of that film must always be carried out under wet conditions to eliminate fire hazard. We have found that, even though a small proportion of one of these antifoam esters should remain in-a cellulose ester which is subsequently employed to prepare sheeting or film therefrom, the properties of the cellulose ster are not adversew afiected. As our invention contemplates the use of only small amounts of the ester, the cellulose material, which is have properties as good as that recovered from a similar scrap by a process in 1 which our invention is not employed.

The following example illustrates the comminution of film in accordance with our invention:

2-ethyi hexyl acetate was sprayed through a. very flue name into the chopping apparatus along witha showerofwater employed towet the film scrap just before it reaches the chopping blades. This ester was applied at the rate of .06 lb.-per 100 lbs. of emulsion coated fihn. It was found that inthe chopping process the foam and froth, which present, were absent and that the disadvantages and inconveniences usually associated with comminufing the film ,scrapwere eliminated. The film base, which was cellulose nitrate, was thereupon separated from the water which was present, the water being free of foam and capable of being easily handled.

our invention is particularly directed to a comminuin'ng process in which chopping is employed. nevertheles, it would be useful inany other instance wherethe wet scrap is broken up .50

into smaller units. Our invention is especially valuable in caseswhere the scrap is separated into fine particles, because the greater breaking on or disolving of the emulsion in such a process would contribute to the foaming. Various organic acid esters of cellulose might have been employed for preparing the base of the scrap photographic film, 4

such as cellulose acetate, cellulose acetate propionate or cellulose acetate butyrate and scrap recovery processes reclaiming this type of fllm are also included in our invention. Our invention is useful in film scrap recovery processes regardless of the cellulose derivative from which the film is made providing, of course, the film is comminuted while in a wet condition.

Our invention is generally useful to prevent the foaming of a fluid mass containing gelatine. 'For instance, after the film scrap has been separated from the water or other liquid used to soak it, the liquid may in some cases be subjected to agitation which would cause foaming. The presence of a small amount of one of the esters given would prevent this foaming and thereby facilitate the handling of the liquid.

. We claim:

1. A process for inhibiting the foaming of a fluid mass containing gelatine which comprises incorporating a small amount of a liquid fatty acid ester of a monohydroxy aliphatic alcohol of 6-8 carbon atoms therein prior to an agitation of the acetate.

fatty acid ester of a monohydroxy aliphatic alcohol of 6-8 carbon atoms.

3. A process for comminuting emulsion coated film which comprises finely dividing it while wet in the presence of an acetate of a monohydroxy aliphatic alcohol of 6-8 carbon atoms.

4. A process for comminuting emulsion coated film which comprises chopping the wet film in the ence of a liquid fatty acid ester of a monohydroxy aliphatic alcohol of 6-8 carbon atoms.

'7. A method .of comminuting an emulsion coated film which comprises finely dividing the film while. wet in the presence of 2-ethyl hexyl acetate- 8..A method of comminuting an emulsion coated film which comprises finely dividing the film while wet in the presence of secondary hexyl MAURICE L. PIK'ER. STEPHEN C. POOL.