US2476758A - Process for preparing a bleached keratin meal - Google Patents

Description

July 19, 1949. R.` NEIGER ET AL PROCESS FOR PREPARING AYBLEACHED KERATIN MEAL Filed July 8, 1946 mme:

and 1yaelav Nachazel .y MKM Y m'n/ Attorney:

.Withoutfseoiumhypes-.1in ite -enablcsi products- `.te-'fleeY obtained; which ,site feel-lent. translucent .or transmettent; .including-S @with`theusua1;articia1 resins. These-products Patented July 19, 19949 2,476,758 PRQQESS FOR PREPARNG A BLEACHED KERATIN Richard.'lseifgerg Maryport England, and* Vaclav N achazel, 'Izlove, near Podmoldy,' GzechoslonWikia', assifg-nors yto Messrs. Hornilowa Limited,

-Maryiort, England, a British-company Application July 8, 1946,'.Seral No, 681,799.3@ .In v4.Great Britain April 2,3, .1945

Sect-ien' 1f, Public Law 690, AugnstS, .1946.

:Patent expires April' 23, 1965 Claims. (Cl. ZBO-4123.7)

VThis invention relates tothe process: for. preparing a. bleachedzkeiatin. mealxina fQrm suitable for use in. making.. moulded. articles such as. .-buttons, buckles., `electrical. insulators and timings. .Keratin is generally. deriyed from `.ground horns. V'and hoofs of ,animals but the vgroundproduct .requires purication before it canmbe used. for making. .high class.: ,moulded articles. .When Jrequirecil .for making translucent mouldings vthe keratinmustbe; bleached in order patterns by`snraa.1e through Stencils, sifting that it may be light in shadeor .coloured to a Y fgrinding process. in` which.. alargeproportion. of

the .impuritiesacan be eliminated. :further object is. to zprovide a y.simple bleaching process .for :theselectively groundproducbinvol-.ving .only a reducing .treatment :The selective vgrindingprocess.according to the invention .consists in.-,cr.ushing. theft-aw.I material such as hoofs, and. thensubjectingthe product to, a selective grinding, .and .S-itl'lg.processV in which the impurities.. are largely removed with thepartcles which pass through-thener meshes of the sieves, while the, coarser .particles .of

keratin of a higher degreeof .purity are separated Vand Asuhiected to a further staeeceferindirle.

The bleaching process .according to the invention consists in .Steeping the selected keratin product of substantial pur-.ity .incinte-ammonia .for some hours, separating ,it trom the alkaline solution, acdulating. it and bleachmg, with the aid ofr a reducing agent.

It has been Yfound that a selective grinding and sifting process which removes .a largeproporton ofthe impurities, .followed .by a -fsimpile reducing .treatment in which the material is Lfirst acted upon by dilute lammonia Solution., then neutral- ;ised and treated with areducing agent suchas .sodium formaldehydesulphoxylic acid. withv 0r acid. medium,

Ltend..ftheutselxies..toeccitante.or. therfenmationfef through z stencils.. and s0 .fcrth, .01 .cf course enaque -monldings can also be made Vfrom them .by the addition ,of pigmenting materiale if dee sired.

.Ithas been that therawmaterial. e.. ghoofs, contains a .certain yariable pencentage 0.1 impurities both-.organic and inorganic, unich, if not. removed. .from .the around..ma.terial,` .contaminate in and are.- also veryA oiiicult to bleach by .any known process.Y "Iheimpilrities, @van after Athe bleachnacan. loev feund as Qatk Sneaks -thfroushout ther material.. and they impair the uniformity of the mouldinaas well as the colour.- '-IneyA .are also .objectionable because they ,may .have an .adverse effect .on the physical qual-.ities .of the mouldines. -lhese impurities may be prea- .entin the. term .of .dirt *.adhering.- to or embedded the; surface. of the hoois,..or as incrustationa Thefformerzare v ery. difcult ammore by Wash.- fing, the latter, .of course,..cam19t be removedV by .washing at all.v In `order remoyethese im.- pur-ities. the renewing methods. haye been .develped:

A-fterbeing'washed the hoofs are dried. in pref.- erably. vertical drying. `shafts.. for approximately 24 to 3.6 hours. at temperatures below the boil;- Ving .point .of water, .up to,y about 89 .or 90 C., and-then allowed-to..cooi.-down to room. .temperature. kBy .this .process most .ofthe free. water is .removed and. .the .subsequent .crushing requires .-sulostantiallyr less. time thannwithout .the previous drying. At Athesame time the. and: foreign matter .are` loosened, part` pee1s..o ff..and: is. sep.- arated. from-the hoofs when: passing .over .-sieyes at the bottom of the .shaft through Ywhich .the nner foreign .matter .falla This mechanical -nurlflcationmay be imnmyedby thawing. off air tlncrleh theoryine shafts.. '.lhe hoois are nrst .erusned :and .instead .of grinding the crushed; hcofs Single grinder 11.1. One .operatlon until: thev .desiredt -neness. is reached, the jglnding. is .electedin. .a Series. of .two or. mote .e .nera each. with its .own :selfecontained re.- ceiyaraeletators, andsieye compartments givins what maybe termed.. .a selective Yerirleing process.

"The crushing. is` preferably effected. int .a hammer mill which-breaks@ or .granulates 1the nente. and. .the grinding eiected preferahlyY .t1-.ish zspeecl --impact grinders. or pulverisers .auch as nin .mills so that the breaking elect .each

the `vctmtrolled .by varying the :speed-0f rotation. The .selective grinding-:procese is based 'onztheviollowine theory I The crushing of the hoofs is facilitated by the presence of encrusted or embedded impurities, which constitute points of weakness in the hoof structure so that impact fracture occurs readily at those points where foreign matter is present. The liberated impurities then pulverise much more quickly to a finer powder than the hoof fragments. The material is then passed over a number of sieves of different mesh, and the finer particles containing most of the impurities and dirt fall through the sieves and are so separated from the coarse material which is then conveyed to the next grinder and the whole process is repeated. It is advisable to grind the hoofs firstly in one or more grinders with a speed of 2000 to 3000 R. P. M. and then in one or more grinders at a higher speed, say 4000 to 6000 R. P. M. The ground material which falls from each of the machines is passed through a separate set of elevators and sieves enabling the various grades to be differentiated both with regard to their mesh size and purity. It is very important to start the grinding at lower speed because the pulverizing action is then gradually increased and favours the selective grinding and separation. The further the process advances the cleaner do the separated materials become.

A suitable lay-out of plant for this purpose is indicated in the accompanying diagram which shows a flow sheet of the plant. The raw material such as hoofs is fed through a preliminary Washer a to driers b through which hot air from a fan c is passed. The dried material is raised by an elevator d and delivered to a magnetic separator m1 and a hammer mill or crusher e. The product from the mill e is raised by an elevator f and delivered to rotary sieves g1, g2, of different degrees of fineness, the flne through products which contain a good deal of foreign matter being collected in sacks s1, s2, while the overs are carried by elevator i and delivered to bins k1. A fan p1 extracts dust-laden air from the input end of elevator f and the rotary sieves g1, g2, the dust being ycollected in dust collector o1 which delivers it to a sack h1. From bins k1 the material passes through another magnetic separator m2 to an impact'pulveriser l1 which may run at say 3000 R. P. M. Part of the output from pulveriser l1 goes to a cyclone-type separator n1 from which air is extracted through a dust collector o2 by a fan p2, the dust being collected in sack h2. Another part of the output goes to one of a series of elevators q delivering the product to one of the plansifters r1 to r6, these being sift- `ing machines having multiple sieve units which are horizontally agitated.

Additional grinding bins k2 and k3l are provided which receive coarser material fed back as v overs from some of the plansifters r1 to r6 by certain of the elevators q. The output from the bins k2 and k3 is delivered past magnetic separators m3 and m5 respectively to impact pulverisers F and Z4 running at say 4000 to 6000 R. P. M. and connected to cyclone-type separators n and n". The major part of the output of pulverisers l2 and Z4 goes to the elevators q and the plansifters. An intermediate magnetic separator m4, pulveriser Z3 and cyclone-type separator n3 operate upon coarse overs fed back from some of the plansifters r1 to T5, and return part of the pulverised product to the plansifters again. The pulveriser Z3 may run at say 6000 R. P. M. The dust-laden air from separators nl and n2 goes to dust collector o2 and fan p2, while dust-laden air from separators n3 and n4 goes to dust collector o3 and 4 fan p3. The dust from collector o2 is received in sack h2, and the dust from collector o3 goes to sack h3. The graded products from the plansitters r1 to r6 are collected in sacks s3 to S10. This flow sheet is to be regarded only as one example of a suitable plant.

The products delivered from the various plansifter compartments into sacks s3 to SB are of different grades and purity depending upon the steps of grinding and sieving which they have passed through. The purest types are well adapted for bleaching, compounding with articial resins and moulding to give products of a high translucency, suited for colouring, and for further treatment such as surface spraying or sifting through stencils to produce articles resembling natural horn or other materials. The less pure products, as well as those received in sacks h1, h2, h3 and s1, s2 can be mixed with articial resins and colouring matter to produce good quality opaque articles but are not pure enough to justify refining and bleaching.

It has been proved analytically that the ash content, i. e. the inorganic material in the product received in the sacks s3 to s1 decreases from about 2.5% down to 0.2% in proportion as the grades of the material improve in purity in the course of the selective grinding and sieving process. The material so produced is cleaner and more uniform than the products obtained by the usual grinding methods, and represents an ideal starting material for the further refining treatment. When mixed with an artificial resin and moulded under heat and pressure this material results in a moulding of yellowish colour` and milky-opaque appearance. In order to obtain a material giving a moulding of lighter colour and greater translucency, this product requires further treatment, consisting of refining and bleaching. This treatment is preferably effected in the following manner:

Firstly, the material is treated for 16 to 24 hours with an ammoniacal solution of say 0.5% strength. This treatment results in making the product lighter in colour as Well as causing a loosening and slight swelling of the keratin substance without however chemically attacking the substance. The subsequent bleaching treatment with a reducing agent, or a combination of agents, has a far better effect than without a preceding ammonia (alkali) treatment.

It is undesirable to employ sodiumor potassium-hydroxide as an alkaline agent, as these chemicals-even in dilute solutions-tend to cause splitting of the protein substance, especially of the cystin. Cystin, which is contained in hoofs up to 15% is easily split up by alkali (caustic) evolving hydrogen-sulphide. When neutralized with acid, colloidal sulphur is formed. The protein is partly destroyed down to the structure of animal glue. This results in a considerable darkening of the moulding caused by oxidation and other reactions catalysed by the heat of the moulding process. We have ascertained that the pretreatment of the hoof substance with dilute (1t/10) ammonia solutions results in the required loosening of the particles, Without the above mentioned disadvantages of NaOH and KOH. Even 411. solutions of ammonia do not cause visible destruction of the keratin, whereas, NaOH or KOI-l would destroy the keratin irreversibly. If the material pretreated in this way is mixed with a resin and pressed under heat, the moulding is of greater translucency and lighter colour than the untreated material. The mouldtreatment: v

I Example 1 Hoofmeal A parts by weight" 550 0.88 ammonia` l v parts 10 Water do 1800 are; agitatedfor 16 to: 24V hours and the water subsequentlyvremoved by centrifuging. The material can be` washed if required, before placing inf 1500 partsv of'jwater. The' water, which is slightly alkaline to litmus,g isV neutralised with iron-free hydrochloric acid, and 15 to 20 parts of sodium formaldehyde sulphoxylic acid are added under constant stirring. The pI-I value of the solution is then lowered to approximately 4.5 to 5.5 by the addition of acid. By the acidification of the solution the reducing power of the agent is accelerated, and certain impurities are dissolved in the acid medium. It is necessary to adjust the pH value which, at the beginning of the process, has a tendency to rise. The material is then centrifuged, washed with water until the pH value of the washing water remains slightly below '1. The material is finally dried at 45-50 C.

Example 2 25 parts of hoofmeal in 125 parts of n/10 ammonia are maintained at room temperature for 6 hours, with constant stirring. After neutralising and washing, the water is removed and the material put into 90 parts of water at approximately 90 degrees C.r in which 0.7 to 1.5 parts of sodium formaldehyde sulphoxylic acid are dissolved. The temperature is kept up to 70 to 80 C. for 2 to 6 hours. Steaming of the material must be prevented. The material is then centrifuged, washed with water and dried at 45 C.

Example 4 As in Example 3, with the exception that the pH value of the bleaching solution is brought down to from 5 to 3 as may be found necessary. It has to be borne in mind that We are dealing with an organic material which Varies with the origin of the cattle, and consequently the methods employed have to be varied within certain limits.

All the materials obtained by the methods described in the examples when moulded under heat and pressure show a great improvement in colour and translucency. They can be moulded into many articles, of limited size, as for example small electrical insulators or fittings, buttons and slides. The mouldings have to be hardened in formaldehyde solutions but their resistance to Water if moulded without additions of resin, is rather poor.

A simple reducing treatment following When "incorporated into: amlnolformaldehyde resins, as for instanceureaormel'am'ine formaldehyde condensation. products; moulding powders are obtainedwhich can be mouldediat' 145 to C., and a-pressure of ltoll/z tons per square inch. The resulting mouldings.- are of I great clarity witnout having lostv their hornlikeappearance,

are highly resistant tewater, andy combine the.

hard brilliancy of the finish-'of asyntheticresin with the soft sheen of the natural horn. The mouldings show all the characteristics of the amino-aldehyde resins andcan-be machinedY and turned to any required shape. The-perfect uni'- formity of the material makes it possible to obtain the most delicate shades in translucent,

semi-transparent and opaque varieties by the usual dyeing methods. The moulding. powder has a good ow and cures satisfactorily.

When mixed with phenol-formaldehyde resin the moulding 'powdercan-be dyed to a greater variety of--shades than the usual wood orcellulose-filledA moulding compounds.

Although` hooishafve` been referred to as the preferred raw material for the ground keratin, horns and other natural materials rich in keratin can be used, but the best quality products are generally made from hoofs in the manner hereinbefore described.

We claim:

1. A process of preparing keratin meal for use in moulding compositions, consisting in crushing natural animal products of the class consisting of horns and hoofs composed mainly of keratin, and subjecting the crushed product to a plurality of stages of grinding increasing in intensity from one stage to another, and to intermediate sieving, wherein loosened foreign matter is eliminated, the overs from the last stage of sieving comprising keratin meal in a relatively high degree of purity, steeping the keratin meal in dilute ammonia for a period of several hours duration, separating the alkaline solution from the keratin meal, placing the separated product in Water, neutralizing it with a weak solution of acid, and stirring into the liquid a reducing agent having bleaching properties containing a substance selected from the group consisting of sodium formaldehyde sulphoxylic acid and sodium hyposulphite, separating the product from the liquid, washing and drying it.

2. A process of preparing keratin meal as claimed in claim 1 wherein the reducing agent comprises sodium formaldehyde sulphoxylic acid.

3. A process of preparing keratin meal as claimed in claim 1 wherein the reducing agent comprises sodium formaldehyde sulphoxylic acid and sodium hyposulphite.

4. A process of preparing keratin meal for use in moulding compositions, consisting of crushing natural animal products of the class consisting of honrs and hoofs composed mainly of keratin, and subjecting the crushed product to a plurality of stages of grinding increasing in intensity from one stage to another, and to intermediate sieving, wherein loosened foreign matter is eliminated, the overs from the last stage of sieving comprising keratin meal in a relatively high degree of purity, steeping the keratin meal in dilute ammonia for a period of several hours, centrifuging to separate out the alkaline liquid, adding water to the product, neutralising with iron-free hydrochloric aci-d, adding a reducing agent having bleaching properties containing a substance selected from the group consisting of sodium formaldehyde sulphoxylic acid and sodium hypo'sulphite,` adding more acid to lower ythe pH value of the liquid to 5.5 or less, centrifugng the product, washing and drying the product.

5. A process of preparing keratin meal for use in moulding compositions, consisting in crushing natural animal products of the class consisting of horns and hoofs composed mainly of keratin, and subjecting the crushed product to a plurality of stages of grinding increasing in intensity from one stage to another, and to intermediate sieving, wherein loosened foreign matter is eliminated, the overs from the last stage of sieving comprising keratin meal ina relatively high degree of purity, steeping the keratin meal in dilute ammonia for a period of several hours duration, adding a reducing agent having bleaching properties comprising a mixture of sodium hyposulphite and sodium formaldehyde sulphoxylic acid, and subsequently adding acid to reduce the pH value of the liquid below 5.5, separating the product from the liquid, washing and drying it.

RICHARD NEIGER. VACLAV NACHAZEL.

' REFERENCES CITED The following referenlces are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 687,219 Gai Nov. 26, 1901 867,167 Stiegelmann et al. Sept. 24, 1907 1,594,633 Schar Aug. 3, 1926 2,072,665 Campbell et al Mar. 2, 1937 FOREIGN PATENTS Number Country Date 423 Great Britain Apr. 1l, 1856 OTHER REFERENCES Lehmann: Melliand Textil Berichte, vol. 24, pp. 1 to 5 (Jan. 1943).

Images