US2271389A - Treated casein and process - Google Patents

Description

Patented Jan. 27, 1942 UNITED: STATES PATENT m Izsusss p I i N. Y., asaignori to The Borden Company, New York, N. Y., a corporation of lew Jersey Application January 3, 1940,

. Serial so. 313,302

iclaims. (Cl. 1065-146) v -fore in common use have been entirely satlslac It is well known that caseln'dissolves in alkaline solutions, suchas solutions of borax, tri-- sodium phosphate, soda ash, potassium carbonate,

ammonia, triethanolamine, as well as in the presence of nm. The amounts of these solvents necessary to dissolve a particular casein and the 7 properties of the casein solution when made will depend (among other factors) upon the quality of the particular casein used and this in turn depends upon the manner in which the asein has been prepared from the milk. It is tions to foam. Such foamy casein solutions are particularly troublesome in most manufacturing -p w A for instance, when caseinis mixed with.

graphing in particular. In so coating paper, it is customary to make up what is-termed paper coating color," namely water containing dissolved milk casein and suspended pigments such as clay, satin white, blancuflxe and-others (white and/or colored), sometimes also containing dissolved dyestuifsotanalkaliresistlngnature. when the color has a tendency to foam during the.

coating operation, bubbles may be formed on the surface of the paper, which break during the drying-of the coating, causing pin holes and, a

in the usual way, does not to the same extent other imperfections in the coating. Such-coated paper does not give a clear and satisfactory surface design, when printed or lithographed.

Many proposals have been made heretofore for 'ameans of preventing the foaming tendency of casein. including the prevention of foaming of paper coating color containing casein. Also to prevent this tendency in casein solutions and mixtures of casein with other substances in general, and so far as we are aware of with only varying degrees of success, small amounts of lard oilmixedwith sulphonatedoilshave beenrecommended to assist in preventing or limiting thisfoaming tendency. Other suggestions havc'been made including the'additionof amyl alcoholorpine oil to the casein solution or to. paper coloror sizing material. Sometimes it has been found necessary to also add small amounts of foam abet-ins agents after a papercolor mix .put into the color box or foimtain' ofqthe'paper well known that diilerent commercial ca'seins vary a 4 great deal in regard to the tendency of the solucoating'm'ixtur'ea, a small amount'of tributyl cit- .tributylcitrateJ! added to). paper coating color 'tory. e

In our search fora toan'i abatenwe have dis-' covered that there are certain chemicals ,which 5 may befof value as foam abaters or arresters hen added to the liquid coating mixture (the color") and yet which substances applied as a coating to the driedparticles of casein prior to dissolving same,-do not act in the same manner as regards preventing foam; We have foundthat certain chemicals are relatively inemcient as foam abaters when added to the prepared coating mix.- ture or to the casein solution, whereas, small amounts of the samechemicals when'coated onto and thepasein thereafter dissolved by the methods and tested for foam development..: produce remarkably .sood results,

either from the standpoint .of' largely arresting the tendency to 10am in a simple solution of the casein, .or in the final mineral-casein-water mixture referred to as color.

. We have in our research inadeycareful with apgreat variety of-substances in order to determine their value as :f oam arresters orfoam abaterswith casein solutions, by means *0! coat ing or spraying onto the dry casein, small amounts of various substances for this purpose. During this series of. tests we have found for example that when a. relatively small percentage of tributyl phosphate is mixed into. a casein solution for-into a paper fcolorf it is fairly satisfactory for tendency to foam, yetthis same tributyl phosphategwhen putonto the dry casein (e. g. as a spray), and the casein thereafterdissolved stop or arrest-the foaming tendency. In a number of'otherinstances'this peculiar condition has been found wlthvvarious. chemicals; and with certain other 'chemicals, the reverse condition the te c of pa r-comps m ures containing toioam, by applying, to the soliddry case which st? be'dis clved and used in new rate. shquad be applied to the solid 7 m". is preferably in the air-' WP?! WWW "4 w n is dwlvgd in' alkalt In factwhen an-equal. amount of the.

reduce the;t endency:.to.foam to such an extent" coating machine. .Noneolr'the methods hereto-"j' as when applied to the solid casein, before dissolving. Thus, very useful results have been produced by spraying the tributyl citrate upon the dry casein (or in any other manner coating the casein particles with the small amount of tributyl citrate). and subsequently dissolving the casein in an alkali solution, and incorporating the pigments, etc. The best amount of the tributyl citratetobeusedwithaparticularcaseimto give the most satisfactory results, should iflrst be determined as for that particular lot of casein. In using high grade caseins, we have sometimes found small amounts such as 0.2% to be satis factory, although in some cases where the foaming tendency of the casein is high, we prefer to use much larger amounts such as 1%. Based on our experimentation to date, we believe that not more than 5% of the tributyl citrate would be necessary in any case. After adding the citrate, the casein can be dissolved at once, or after stora e. shipp etc- In order to more fully explain our invention we give herewith by way of illustration, several examples of the utilization of the discoveries leading up to this process, although we do not limit ourselves in any way to the examples cited.

Exams: 1

Into a suitable mixer such as the usual spiral measurement taken to indicate the degree of speed with which the developed foam receded or broke down. Thereaftehthe solution was allow the foam which was developed during this test to entirely recede.

ample N0. 1.

mixer containing the proper spiral agitator, we

placed 400 parts of ordinary commercial casein which had been ground, for example, to all pass through a standard 24 mesh wire screen. The spiral in the mixer, by any convenient means, was made to revolve at a fairLv rapid speed and thereafter we sprayed 1 part .25%) of com-.

mercial tributyl citrate onto the casein while being agitated in the spiral mixer. Thereafter, operation of the mixer was continued for about minutes, the material then removed from the mixer and tested for foaming tendency as follows:

100 gms. of the tributyl citrate treated casein was added. to 500 gms. of cold water, mixed to wet the particles and allowed to stand for about to' minutes. Thereafter we added I gms.

- of commercial 26 ammonia, the liquid mass,-

mixed thoroughly and thereafter the receptacle holding the mixture was placed in a water bath and heated, while stirring slowly, to about 140 F. When the casein was completely dissolved we slowly added a further 500 gms. of cold water to this solution, stirring it thoroughly to obtain a uniform solution which was then cooled to '15 Exams: 2

400 parts of casein, 3 parts of tributyl citrate, mixed and prepared exactly as described in Ex- The casein was from the same lot as used in Example 1; A 100 gram sample of this mixture was then dissolved and tested for foaming tendency in the exact manner described under Example No. 1.

' The results of these tests are recorded under Table I. v

Other tests with other types of casein known to much greater foaming tendencies than th casein used in Examples 1 and 2, were also treated with various amounts of tributyl citrate by means of spraying or oiling" the ground dry casein. one particular casein being one known to be extremely difficult to use in commercial operations, from the standpoint of dissolving or preparing the solution because of its great tendency to foam (even foaming over the mixing kettles while the solution is being prepared, unless extra care is used in its preparation). Such 'acaseinwasusedinExamples3 and4.

F. We then made a test to determine the relative foaming tendency of this treated casein by the following method:

Into a one-quart capacity cylindrical glass jar there was placeds400 cc.. of thecasein solution above referred to and the height of the liquid was marked on the Jar. One egg-beater mounted on a Sunbeam Mix-Master mixer was placed in the solution. The beater was started, the beater running840R.P.M.andthebeatingwasoontinued' for exactly 6 minutes (bya stop-watch). Then the beating was discontinued and the height of the liquid plus the foam developed was quickly measured. This by subtraction showed the "height of foam" developed fromthe top of theoriginalliqmdintheiartothetopofthe foam layer. This height of foam developed applies to the particular casein used in this example, modified by the tributyl citrate.

After having measured the height of foam, the solution in the jar was allowed to rest undisturbed for another 5 minute period and a second Exmm: 3

400 partsof a casein (known to be excessively foamy), 3 parts of tributyl citrate. Procedure for preparation was exactly the same as described under Example 1. Thereafter a sample of grams of this mixture was dissolved and the "height foam determined as described under Example 1. The results ofthese tests appear in Table I.

Exmu 4 dissolved and tested for height of foam" as de-l scribed under Example- 1. The results of these tests appear in Table L a control (without thecitrate ma) air-me casein usedinltxamples Sand 4, was treated andtestedinthesamewsy.

I m5 400 parts of commercial sodium cascinato groundtoaiinenesssothat allwillpassthrough *aMmeshscreen. Tothiswasadded4partsof tributyl citrate following the method as described in Example 1'. Thereafter, 100 grams of thetreatedsodhimcaseinatewas addedtom cc.ofooldwater,mixedtowettheparticlesand immediately heated (because sodium caseinate is soluble in water without the additiomof other solvents) to about 140. 1''. After the casein was dissolvedx we added #0. cc. of cold water and stirredthemixture-mtilitwasinauniform out tributyl citrate was similarly amuse consistency. Thereafter this solution was tested for its "height of foam, as per the method described under Example 1 and the results are recorded in Table I.

A sample of this same control, and the results are shdwn in Table I.

other tests were made by preparing a com-5 plete color mixture and thereafter a foamtestwiththiscolormixturebytheusual well-established method (described below) to determine the "foam index in paper coating color mixtures. Inoneoftheseteststhematerlalpra pared under Example 3 was used (with pigments).

In another test the same casein without'treatment with trlbutyl citrate was employed. .The results of thesetests areindicated in Table II. a

The method used for preparing and making the paper color foam index test was as follows:

A casein solution was made up at a concentration of 1 part of the particular casein-to 5 parts caseinate withtreated. as a.

citrate. We do not wish to limit our invention to any definite amount of "trlbutyl citrate to be vaddedtothedrycaseinbutwehavethusfar" will besumcient'in all cases..

found that not over 1% of tributyl citrate seems to besufilcientonanyof the easeinswe-have examined. We believe that quantities below 5% All of the above specific disclosure, including the above examples and the above tables. refers to the treatment of milk casein.

The invention is also applicable I tory results to the treatment of "vegetable casein, which may be, to some extent. considered as a substitute for milk casein in the paper coating art. This material also often shows a;

troublesome foaming tendency. Various tests were made by treating the literature and in commerce, as "vegetable casein or "soya casein), with tributyl citrate by the process described herein, in order to reduce the foaming tendency of products of this nature, namely, isolated vegetable protein. Tests were made as follows: An isolated soybean protein (which in-many of its properties is similar;

to milk casein) was purchased on the market.

'1hisisofaty'pethatiscommerciallyofl'eredto I ,the trade regularly. so

Exams: 6 Into a suitable mixer such as the usual the proper spiral agitator, we placed of water, using ammonia as'given in Example 8 as the solvent for the casein. Other solvents could be used as long asthesame solventis.

used in comparative tests A clayslip-was madeup bymixing 1 part of with 1 part of water to a smooth paste. To parts'of the clay slip were added 06 parts of casein solution which is equivalent to 11 dry casein. This was mixed until smooth 400 parts of dry ground soy-bean isolated protein (also sometimes called "soya casein). The spiral mixer,'by any convenient means, was made to revolve at a fairly rapid speed and thereafter we sprayed 1 part (0.25%) of commercial tributyl citrate onto the isolated protein'while being agitatedin the spiral mixer. Thereafter the mixing was continued for about 5 minutes, the material then removed from the mixer and tested for foaming tendencies. The procedurefor dissolvingand testing the resulting mixture for foam ing tendency was the sameas that described under Example 1, with the exception that a little andstrained throughawirescreentoinsure complete uniformity (a 100 mesh screen was used.

in the present tests).

the clay-casein mix mixsothatthetopofitisefiinchbelowthe surface ofthe liquid. At the end of two minutes stirring; the mix was allowed to stand for one minute. Immediately, thereafter, the weight of 100 cc.ofthesotreatedmixtllrewa8determined. The loss in weight as compared with the weight of 100 cc. mentioned above,is termed the "foam index." 7

- Table 11 Foam index Color mix (casein not treated) 48.5

' 001m mix (casein; with tributyl citrate) Aswillbenotedfromtheresuitsindicatedin Table I and Table II, we obtain a very marked more ammonia was used as the solvent, namely 10 grams of gramsasusedinExample 1.

Exam; 7

' The same procedure was followed as in Example 8 with the exception that we used 2 parts (0.50%) of commercial trlbutyl citrate.

Exsssru 8 Same as Example 6, with the exception that we used 3 parts (0.75%) of commercial tributyl citrate. 1 j

' mixtur s .9

The same as Example 6, with the exception that we used 4 parts (1%) of commercial tributyl citrate. A v

The resulting solutions of the treated isolated soya protein (made in-Examples 6 to 9) were tested for foaming tendencies in the same man-- i net as described under Example 1 and for pm?- pose of control, an untreated sample of the same isolatedsoya protein (without the citrate added) was dissolved in the same, manner as described decrease in the foaming tendency in the casein solutions themselves. an in the P per-color made from the casein, by means of the addition 75 under Example 1. The results obtained in Examples 6 to 9 inclusive plus the control test are indicated in Table 111.

3'. of these relatively small amounts of trlbutyl with satisfac isolated soybean protein (which material is referred to in mixer ammonia in this case instead of "7 which has been pressed cold .or

smoothness is not needed, as in coating wall paper), instead of the isolated vegetable protein, we can use a solvent extracted seed meal,

e. g. a solvent extracted soybean 'press cake at 'a relatively low temperature. This material is ground to an extremely fine condition, and can be used with or without milk' casein or isolated vegetable casein, being treated with tributyl citrate and thereafter dissolved in a mildly alkaline solution,

with or without pigments and/0r dyes, and then used for coating paper.

It is to be understood that after applying the tributyl citrate to the casein, the latter can be stored for a long time, or can be shipped, and/or compounded with any of the materials with which casein is usually compounded, before being dissolved, and the "non-foaming roperty of ,the so treated casein will persist. Thus we may treat the casein at the factoryand ship this to a paper-coating mill to there be dissolved as wanted.

The term casein, as used in the appended,

claims, is intended to include milk casein and isolated vegetable proteins vegetable'casein". and the finely ground solvent-extracted seed meal and also caseinates in general, such as sodium caseinate, ammonium caseinate,. magnesium caseinate, etc., which last three are compounds of. milk casein with a small amount of soda, ammonia or magnesia. Mixtures of such materials are also included.

The casein is preferably, at the beginning of the step of oiling with the citrate, in the usual air dry? conditiom-and the citrate can be used alone or mixed with solvents or diluents v (e. g.

alcohol, etc), w ch also are non-aqueous liquids; but do not have to be completely anhydrous.

The term non-aqueous liquids" is used in the appended claims to distinguish from liquids which consist largely of water.

The tributyl citrate, given in the above examples and specific disclosure, is an alkyl citrate, and tributyl citrate is generally about the most satisfactory alkyl citrate to employ. We do not desire to restrict all of the claims to the butyl compound, nor to the tri-alkyl compound, because alkyl citrate broadly, applied to the casein while the latter is in the solid state will be (to some extent at least) eflective.

We claim:

l. A processof producing casein solutions of reduced, foaming tendency which comprises applying to solid casein, a small amount 01' tributyl ci rate. the amount 01 the latter being not substantially above 5%, based on the amount of said casein, and'thereafter dissolving the casein in an aqueous solvent.

2. A process which comprises agitating a mass of comm-muted solid casein while spraying a substantially non-aqueous liquid material containing tributyl citrate upon said casein, the amount or said citrate'being not substantially more than 5 based on the casein, and thereafter dissolving the so-treated casein in any aqueous alkaline liq= uid, whereby a casein solution is produced having not more than a low foaming tendency.

3. Solid casein carrying" intimately incorporated therewith, an amount of tributyl citrate which is not substantially in excess of 5%, based on the weight or the casein.

4. Solid casein wetted with a fraction of one per cent of tributyl citrate.

JOHN F. CORWIN. ROBERT c. wnrrn.