US3179728A - Process for the preparation of proteinureic fibres and mixed protein-ureic cellulosic fibres - Google Patents

Description

April 20, 1965 s. DONINI 3,1 PROCESS FOR THE PREPARA N OF PRO N" IC FIBRES AND RES MIXED PROTEIN- IC CELLU IC B Filed Feb. 7, 1962 United States Patent PRUCESS FOR THE PREPARATION OF PROTEIN- UREIC FIBRES AND MIXED PROTEHN-UREEC CELLULOSEC FIBRES Sandro Domini, Vials F. Crispi 13, Milan, Ital3 Filed Feb. 7, 1962, Ser. No. 171,604 Claims priority, application Italy, Feb. 7, 1961, 646,461 3 Claims. (Cl. 264-202) The present invention refers to a process for making protein-ureic artificial fibres and mixed protein-ureiccellulosic fibers.

In the technics of the manufacture of artificial textile fibres, those obtained by spinning colloidal solutions of protein or, more exactly, of alkaline substitution products of the same, in an acid coagulation bath, are well known; a typical example of such fibres is the very well known artificial fibre, similar to wool, obtained by spinning a colloidal solution of sodium caseinate in an acid coagulating bath.

Mixed fibres of sodium caseinate and viscose are also well known.

These artificial fibres, and the process of preparing them, were fully described for example in Italian Patents Nos. 348,661 and 367,405.

From an examination of these previous technical documents it can be seen at once that at that time it was considered imperative not to use casein with its original degree of acidity (pH 5.5-6.5) but to operate definitely in an alkaline environment: moreover, as was pointed out in Italian Patent 348,661, only sodium and potassium salts were considered suitable at that time for the formation of solutions of casein capable of being spun.

The surprising discovery has now been made, and this constitutes the essential characteristics of the present invention, that it is not only possible to obtain spinnable solutions of casein although maintaining the original acidity of the casein, but that proteic fibres can be obtained with characteristics of spinnability, appearance, handle, heat-insulation and even microscopic structure much nearer to those of natural wool than those of the artificial wools which were obtained by spinning alkaline caseinates: it may be pointed out here that the products of this invention must not be considered as modifications of the caseinic fibres known hitherto, but rather as products very different from those known up to now. Products obtained with this invention have excellent dyeing properties with all textile dyestuffs, especially with the acid dyes called half wool.

Broadly speaking, this invention foresees the preparation of spinnable casein solutions obtained by emulsifying, in an aqueous stage, lactic casein and urea. In this way a colloidal solution is obtained, free from any combined or added alkali, and which can easily be spun; this colloid has in fact such a high spinnability that it can be spun even by simply dropping into water.

It must be added, however, that the preparation of the aqueous solution of casein and urea must be carried out whilst observing some essential conditions, failing which it is not possible to obtain the desired perfect results.

in general, it is essential that the preparation of the emulsion in an aqueous phase, of casein and urea should not take place by introducing the aqueous dispersive phase all at once into the casein-urea mixture.

The process according to this invention is characterized by comprising the operations of mixing lactic casein and urea mechanically, preferably in the presence of a tensionactive agent, for example ethyl alcohol, for at least 30 minutes until a homogeneous mixture is obtained, adding up to 30% by volume of water necessary to form a colloidal solution of the required concentration and mixing arrears Patented Apr. 20, 1965 slowly for at least minutes; adding the remaining quantity of water slowly during the subsequent 90 minutes, stirring for a further 3 hours, preferably leaving the solution thus obtained to mature for at least 16 hours at a temperature between 20 C. and 24 C.

Once these operations have been carried out spinning can be undertaken without delay, using the standard spinnerets for rayon and other artificial fibres and any one of the known acid coagulating baths: as already mentioned it is quite possible to carry out the spinning in water in view of the insolubility of the colloid, but for obvious technical reasons it is preferable to use an acid coagulating bath, for instance a bath of sulphuric acid, sodium chloride, sulphate of zinc (or sulphate of aluminum).

The usual coagulating baths for rayon can safely be used.

The accompanying drawings show: in FIG. 1 a crosssection of filaments of casein-urea (70%), in FIG. 2 a cross-section of filaments of casein-urea and cellulose (30%).

It must also be pointed out, and this will be illustrated with several examples, that the casein-urea combination according to the present invention is very suitable for mixing with viscose, and this makes it possible to obtain valuable composite fibres.

The examples which follow illustrate, without restrictive eifect, the various aspects of the invention.

Example 1 4-0 kg. of urea are placed into a mixer and 1.5 litres of ethyl alcohol are added, mixing for 1015 minutes until a homogeneous mixture is obtained. Now add 60 kg. of casein and mix again for at least 30 minutes. The emulsion can now be prepared, and great attention must be paid to the method of procedure, which is of very great importance for the purpose of this invention. In general, emulsions should be prepared with a concentration above 30% of casein-urea in water, as with weaker concentrations the solid products may precipitate.

In the present case we shall consider an emulsion of about 30%, which has given excellent results in practical use.

In order to prepare such a solution about 50 kg. of the casein-urea alcohol mixture, prepared as above, will be taken, and litres of water. Obviously the water must not be excessively hard: for preference the hardness should not be above 30 French degrees, but this is not a hard and fast limit.

First of all the 50 kilos of casein-urea-alcohol mixture and 30 litres of water should be put into the mixer and mixed slowly for at least an hour and a half.

Afterwards the remaining 70 litres of water should be poured, from a calibrated receptacle and in a thin stream, for another 90 minutes at least, stirring slowly; the mixer should make from 12 to 18 revolutions per minute.

Great attention should be paid whilst pouring the last 15 litres of water to ensure that the casein-urea mixture swells up properly and forms a homogeneous colloidal solution. The mixer should therefore be left running for another 3 hours and thus the colloidal solution, after maturing for about 24 hours at a temperature between 22 C. and 24 C., will be ready for spinning in any form desired.

Example 2 1200 kg. of viscose must be mixed with 9% cellulose and kg. of casein-urea emulsion about 30%, the latter prepared by the same procedure as in Example 1. The mixture of this emulsion and of the viscose is homogenized in a mixture, and after the phase of de-aeration and maturing one obtains for spinning in an acid coagulata ing bath (for instance: 7% H 80 16% NaCl; 10% ZuSO or Al(SO density 1.2751.3) a yarn which is completely different in appearance from the artificial silk yarn obtained by the viscose or cupraammonium process and with excellent characteristics as regards strength and behaviour in weaving.

The processes of desulphurization and washing, necessary owing to the presence of the viscose, may be carried out in accordance with the usual practice; for bleaching it is advisable to use hydrogen peroxide acidified up to pH 66.5 with acetic acid.

The finishing bath with softener can be a normal neutral bath.

Example 3 800 kg. of about 10% viscose solution are mixed with 250 kg. of 33% casein-urea emulsion prepared according to the procedure described in Example 1. The mixture obtained in this Way, as it is easy to calculate, contains about equal quantities by weight of casein-urea and viscose; it should be borne in mind that the parts and percentages are indicated by weight.

This mixture, after being homogenized, de-aerated and a more accentuated elastic retardation than the yarn in iating bath. Yarns obtained in this way show greater and a more accentuated elastic retardation the yarn in Example 2.

I claim:

1. A process for the preparation of artificial fibres using acidic lactic casein and urea as the starting materiais, comprising the steps of:

(a) mechanically and intimately admixing acidic lactic casein and urea for at least 30 minutes until a homogeneous mixture of said ingredients is achieved;

([2) adding to said mixture a minor fraction of the volume of water which is necessary to form a colloidal solution in water of said ingredients and slow- 1y stirring the resultant mixture for at least 90 minutes;

(c) adding to the slurry thus obtained the remaining fraction of said water volume necessary to form said colloidal solution and stirring for at least 3 additional hours;

(d) allowing the resultant aqueous mixture to ripen for at least 24 hours at a temperature in the range 20 C.-24 (3., and

(e) spinning the thus obtained spinnable casein-urea compound in an acidic coagulation bath to obtain said artificial casein-urea fibres.

2. A process according to claim 1, wherein said mixture of casein and urea as specified in step (a) of claim 1 is prepared in ethanol.

3. A process according to claim 1, wherein a cellulose xanthate solution in carbon disulphide is added to said ripened spinnable casein-urea compound and intimately admixed therewith before spinning.

References Cited by the Examiner UNITED STAT ES PATENTS 2,291,701. 8/42 Dreyfus 18-54 2,318,544 5/43 Thurmond et al. 264202 2,342,994 2/44 Atwood 18-54 2,358,383 9/44 Chibnall et al 1854 2,398,625 4/46 Kadt 1854 2,516,700 7/50 Holloway et al 106-146 2,548,357 4/51 Perrctti 2642=()2 FOREIGN PATENTS 483,731 4/38 Great Britain.

ALEXANDER H. BRODMERKEL, Primary Examiner.

MORRIS LIEBMAN, Examiner.

Claims (1)

1. A PROCESS FOR THE PREPARATION OF ARTIFICIAL FIBRES USING ACIDIC LACTIC CASEIN AND UREA AS THE STARTNG MATERIALS, COMPRISING THE STEPS OF: (A) MECHANICALLY AND INITIMATELY ADMIXING ACIDIC LACTIC CASEIN AND UREA FOR AT LEAST 30 MINUTES UNTIL A HOMOGENEOUS MIXTURE OF SAID INGREDIENTS IS ACHIEVED; (B) ADDING TO SAID MIXTURE A MINOR FRACTION OF THE VOLUME OF WATER WHICH IS NECCESSARY TO FORM A COLLOIDAL SOLUTION IN WATER OF SAID INGREDIENTS AND SLOWLY STIRRING THE RESULTANT MIXTURE FOR AT LEAST 90 MINUTES; (C) ADDING TO THE SLURRY THUS OBTAINED THE REMAINING FRACTION OF SAID WATER VOLUME NECCESSARY TO FORM SAID COLLOIDAL SOLUTION AND STIRRING FOR AT LEAST 3 ADDITIONAL HOURS; (D) ALLOWING THE RESULTANT AQUEOUS MIXTURE TO RIPEN FOR AT LEAST 24 HOURS AT A TEMPERATURE IN THE RANGE 20*C-24*C., AND (E) SPINNING THE THUS OBTAINED SPINNABLE CASEIN-UREA COMPOUND IN AN ACDIC COAGULATION BATH TO OBTAIN SAID ARTIFICIAL CASEIN-UREA FIBERS.

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