US2665966A

US2665966A - Method for insolubilizing spun protein filamentary products

Info

Publication number: US2665966A
Application number: US235718A
Authority: US
Inventors: Robin H K Thomson
Original assignee: Imperial Chemical Industries Ltd
Current assignee: Imperial Chemical Industries Ltd
Priority date: 1950-08-28
Filing date: 1951-07-09
Publication date: 1954-01-12
Anticipated expiration: 1971-01-12
Also published as: BE505443A; GB708057A; CH303631A; FR1048386A; DE915491C; NL79057C

Description

Jan. 12, 1954 R. H. K. THOMSON 2,665,966

METHOD FOR .msowsruzmc SPUN PROTEIN FILAMENTARY PRODUCTS Filed July 9, 1951 Robin Jiamz'li'on Kizdall Thom-9oz;

Patented Jan. 12, 1954 METHOD FOR IN SOLUBILI-ZIN G SPUN PRO- TEIN FILAMENTARY PRODUCTS Robin H. K. Thomson, to Imperial Ghemi'ca Fairlie, Scotland, assignor l Industries. Limited, a cor-- porationof. Great-Britain.

Application July 9, 1951, Serial No. 235,718

Claims priority, application Great-Britain August 28, 1950 Claims.

The present invention relates to a new or improved method for insolubilising artificial filaments, threads, fibres and the like filamentary products obtained by the spinning of solutions of proteins, for instance, peanut protein or. casein, in aqueous alkaline or other suitable aqueous solvent media into suitable acidified. saline coagulating baths.

In British patent specification No. 597,497. there. is described. and. claimed inter alia a. method of. insolubilising artificial filamentary products obtained by the spinning of solutions. of vegetable seed globulins, for instance peanut proteins, or phospho-proteins, for instance casein, in aqueous alkaline or other aqueous solvent mediav into suitable acidified saline coagulating baths. which.

comprises treating the said filamentary products in an aqueous formaldehyde bath saturated toboth sodium chloride and sodium sulphate or to both sodium chloride and magnesiumsulphate at a pH of 4 to 6 and at a temperature not exceed.- ing 60 C. and thereafter treating the filamentary products in an aqueous formaldehydebath strongly acidified with sulphuric acid and saturated with sodium sulphate. or magnesium sulphate at the temperature employed, the saidstrongly acidified formaldehyde bath being at a raised temperature.

It is stated therein that the coagulated filaments can first be passed through a saturatedsodium chloride bath at approximately C. in which they remain until their longitudinal contractility has been greatly reduced. It is filamentary productswhichhave been thus relaxed which are subsequently treated in the twoaforesaid baths. The treating liquid in whichthe filamentary products are thus relaxed will. hereinafter he referred to as relaxing solutions or relaxing treating liquids.

It has now been found that it is possible to provide a more economical process than hereto fore for the productionof insolubilised proteinous filamentary products in a period of time lying for instance between 1 and minutes and under conditions in which the filaments of a travelling tow remain open and distinct by employing. solutions wherein sodium sulphate is at least the: main saline constituent. in. the acidified. saline coagulating bath, inthe relaxing solution, inthe formaldehyde solution at pH between 4 and 7,

and in the formaldehyde solution strongly acidified with sulphuric acid.

We are aware that British patent specification No. 623,460 describes and claims inter alia a method of treating a continuously advancin tow o1 filaments by immersion in a treating liquid for a relatively long period of time by providing a horizontal ring-trough rotatable about a vertical axis, passing treaung liquid in acontinuous manner through said, ring-trough and rotating the ring-trough with substantially the same directional speed as the mean circular velocity attained by the said treating liquid in said ringtrough, inducing a vibratory motion substantially radial to the centre of the rotating ring-trough in the advancing tow at a position vertically above the treat-mg liquid, permitting the thus treated swaying advancing tow to fall into the treating liquid and to form itself therein into folds on thefioor of the rotating trough immediately below the region where it enters the liquid and also regulating the speed of rotation of the ring-trough so that on withdrawing the tow from out of the treating liquid at any desired distance away from the said region measured along thecircumference of the ring-trough the said'tow has remained in the treating liquid for the desired period of time.

In said patent specification there is disclosed by way of example the coagulation of an extruded caustic soda solution of groundnut globulin by a coagulating solution containing sodium sulphate as its saline constituent, the relaxing of.

the continuously advancing tow of filaments in a solution of sodiumsulp-hate saturated at 1'5 (3.,-

the treatment ofthethus relaxed filaments in a solution of sodium sulphate saturated at 0; containing lt formaldehyde at pH 5 and the further treatment. of the tow in a treating liquor. at a temperature of C.. and consisting of a solution of sodium sulphate saturated at C.

containing 1 /2970 formaldehyde and 20% sulphuric acid by volume and the subsequentwashing and drying of the thus treated tow. There is no statement however that a continuously ad.- vancing tow treated in: this manner is insolubilised, that isv tosay is resistant to the action of a bath containing 6.1% sulphuricacid and 0.25% sodium. sulphate.- when. immersed therein for minutes at 97 C.

It has now been found that in order to produce insolubilised filaments for example in accordance with the method of British patent specification No. 623,460 it is essential that there should be at least a minimum quantity of a chlorine ion present at least in the formaldehyde solution strongly acidified with sulphuric acid.

In patent specification No. 637,025 there is described and claimed inter alia a method for insolubilising. continuously travelling tows of artificial filamentary products obtained by the spinning of solutions of vegetable seed globulins, for instance, peanut globulins, or of phospho-proteins for instance, casein, in aqueous alkaline or other aqueous solvent media into acidified'saline coagulating baths by advancing the said continuously travelling tow through a tubular passage by means of a turbulent stream of an aqueous formaldehyde solution saturated with sodium chloride and containing sodium sulphateor magnesium sulphate in solution and having a pH of 4 to 6, occupying said tubular passage, and

thereafter advancing the so treated tow through another tubular passage by means of a turbulent stream of another aqueous formaldehyde'solution that is at a higher temperature than the said formaldehyde solution of pH 4 to 6, this hotter aqueous formaldehyde solution occupying said other tubular passage and being strongly acidified with sulphuric acid and saturated with sodium sulphate or magnesium sulphate at the temperature employed. It has been found that as the process proceeds that the strongly acidified formaldehyde solution becomes more concentrated in sodium chloride due to carry-over and that steps have to be taken to keep the sodium chloride constant in said strongly acidified formaldehyde solution for the rate of insolubilisation to be constant.

The object of the present invention is to provide a process which is adapted to insolubilise under non-tensioning conditions a continuously travelling tow of protein filaments and in which the filaments of the travelling tow remain open and distinct by employing a series of solutions wherein the total quantity of sodium chloride included and distributed in the series formed by a relaxing solution having sodium sulphate as its stipulated saline constituent, a formaldehyde solution having a pH preferably between 4 and 7 and having sodium sulphate as its stipulated saline constituent and a formaldehyde solution strongly acidified with sulphuric acid and having sodium sulphate as its main stipulated saline constituent and sodium chloride as an additional stipulated constituent at least approaches the minimum quantity required for insolubilisation to occur in a stipulated time lying between a period of time of 1 and 30 minutes.

A further object of the present invention is to employ solutions having a lower concentration of reagents than was heretofore considered possible, and particularly with respect to the ooncentration of the reagents in the formaldehyde solution strongly acidified with sulphuric acid thereby effecting economies in the amount of reagents lost due to the taking up of the solutions by the filaments undergoing insolubilisation with the subsequent removal by washing of the reagents thus present in the finally insolubilised filaments.

According to the present invention the method of insolubilising under non-tensioning conditions in a period of time lying for instance between 1 and30 minutes a continuous travelling tow of coagulated filaments obtained by the spinning of aqueous alkaline solutions of protein into sulphuric acid/sodium sulphate coagulating baths and under such conditions that the travelling tow remains open and the filaments distinct comprises treating the travelling tow of coagulated filaments in a relaxing solution containing not less than 220 g. of sodium sulphate per litre of solution, treating the thus relaxed filaments at a temperature not exceeding 80 and preferably above 40 C. in an aqueous formaldehyde solution containing not less than 210 g. sodium sulphate per litre of solution and having a pl-I value preferably between 4 and 7 and thereafter treating the travelling tow at a raised temperature in a strongly acidified aqueous formaldehyde solution containing per litre of solution not less than 340 g. sodium sulphate, not less than 15 g. sodium chloride, or a quantity of a reagent producing a chlorine ion and equivalent to an amount at least not less than 15 g. sodium chloride, and not less than 200 g. sulphuric acid.

The second formaldehyde bath, i. e. the said strongly acidified formaldehyde solution can be used at temperatures higher than 90 though preferably the temperature is between 70 and 98 C.

It is desirable for the treating solutions preceding the said strongly acidified formaldehyde solution to be free of sodium chloride unless it is required to shorten the time of treatment. Again the higher the quantity of sodium chloride present in the said strongly acidified formaldehyde solution the shorter is the time necessary to obtain insoluoilised protein filaments, i. e. protein filaments which do notdissolve in a solution of r 0.1% sulphuric acid and 0.25% sodium sulphate when immersed therein for minutes at 97 C.

It will be understood furthermore that in so far as the relaxing solution and the first formaldehyde solution are concerned, although it is desirable in accordance with the invention not to increase the concentration of the sodium sulphate to values higher than 220 g. and 216 g. respectively, it is nevertheless possible to carry out continuous insolubilisation in a period of time between 1 and 30 minutes if these figures are exceeded.

In so far as the second formaldehyde solution is concerned, it is again desirable to keep as near as possible to the minimum concentrations given. Here, however, it is necessary to carry out preliminary investigations to ascertain the maxi-- mum values of sodium sulphate and sulphuric acid if the minimum concentration required for the sodium chloride is exceeded as the sodium chloride, sodium sulphate, and sulphuric acid concentrations are inter-related. A higher concentration of sodium sulphate can be compensated for by a higher concentration in sulphuric acid or sodium chloride or both. A higher sulphuric acid concentration may be compensated for by a higher sodium sulphate or a lower sodium chloride concentration and a higher sodium chloride concentration may be compensated for a lower sulphuric acid or higher sodium sulphate concentration it being understood that the concentrations of sodium sulphate, sulphuric acid and sodium chloride must not be allowed to fall below the minimum concentration stipulated for each of these ingredients.

In so far as the first formaldehyde solution is concerned, it is desirable that the temperature should be above 40 C.

The invention is illustrated by the following example in which the parts are parts by weight except where otherwise indicated-and with referencetothe diagrammatic drawing accompanying the specification for the jinsolubilisation in a periodof .15 minutes'o'f a continuous tow of groundnut-globulin. 3 1

A solution of groundnut globulin containing 20% globulin, 1.1% sodium hydroxide and 78.9%

water is extrudedthrough a spinneretj into a coagulating bath 2 containing 240 1 g./l. sodium sulphate and 20 g./l. sulphuric acid. The coagulated tow 3 is stretched between godets, 5 and then treated for 4 minutes with a solution containing 230 g./l. sodium sulphate, at a pH 8.5 at 23 to 30 C. contained in the trough of a ringtrough 7 according to the method described and claimed in patent specification No. 623,460. This treatment is effected by leading the tow 3 under tension to a godet 6 situated vertically above the centre line of the trough of the ring-trough 7 through a reciprocating device 8 at least 3 feet above the surface of the liquor in the trough and so into the trough in which the fibre is deposited in a zig-zag manner. This ring-trough consists of a solid centre section 2 feet in diameter with a trough 0.5 feet wide and 4 inches deep but integrally joined to it and is made of mild steel. The ring-trough contains a base of wire gauze 9 and revolves in a circular trough l3 3 feet 4 inches external diameter, 1 foot 7 inches internal diameter and 6 inches deep, also of mild steel fitted with an adjustable weir so that the height of liquor in the trough may be varied at will. The tow 3 sinks on to the base 9 of the trough i and is carried around with the trough l which revolves once in 3 minutes. The tow 3 is taken up not less than 3 inches from the fibre met and is then mangled between squeeze rolls i i after which it is stretched between two godets l2 and [3.

The tow is now treated for 4 minutes in a solution containing 220 g./l. sodium sulphate, and 10 to g./l. formaldehyde at pH 5 and at 55 C. contained in the trough of a ring-trough 16 similar to the ring-trough 1 and again according to the method described and claimed in patent specification No. 623,460. This operation is effected by passing the tow 3 from a godet l3 situated vertically above the centre line of the trough of the said ring-trough I6 through a reciprocating spacing device I5. The tow 3 after leaving the trough of the ring-trough I6 is mangled between squeeze rolls l1 and passed from a godet l8 vertically downwards according to the method described and claimed in patent specification No. 642,359 into the constant feed cone l9 where it is picked up by the insolubilising liquid which enters the feed cone through a pipe 20 and is then carried through the tube 2| and a glass cone 22 into the inclined tube 23. The tube 2| is of inch diameter and the glass cone 22 is 4 inches in diameter at the open end. The composition of the insolubilising liquid is 340 g./l. sodium sulphate, 40 g./l. sodium chloride, 270 g./l. sulphuric acid and 10 to 15 g./1. formaldehyde, and it enters the tube 23 at 90 C., and overflows at 85 C. The speed of the liquid flowing through tube 2| is controlled by the difference in levels of the liquid at the inlet cone I9 and the overflow at the exit end of the tube 23 which in this case is 4 inches. The tube 23 is of glass 6 inches in diameter and 8 feet long inclined so that the exit end is raised 14 inches above the inlet end. At the exit end of the tube 23 is attached a perforated lip 24 made of lead Which raises the level of the liquid in the

tube

12,3 and allows aitrto -flow away:without giving rise toilocal. regions iof high speed fiow. :On entering the incl ned tube123 through the funnel .22 the tow forms a loose column about 4 feet long against :the'upperjsurfaceof the tube 23 filling roughly about of the cross sectional area and is .then removed at the exit end by the godet 25. The peripheral speed of this godet is so adjusted that the time of passage through the tube 23 is constant and around minutes, whichis j What Ijclaim-isr q *1. n process -of insolubilizing'at least un'tlrthe filaments do not dissolve in a bath containing 0.1% sulfuric acid and 0.25% sodium sulfate when immersed therein for 90 minutes at 97 C., under conditions substantially free from tension, a continuous travelling tow of protein filaments obtained by spinning aqueous alkaline solutions of proteins selected from the group consisting of vegetable seed globulins and phospho-proteins into a sulfuric acid-sodium sulfate coagulating bath, said process comprising the steps of relaxing said tow of coagulated filaments by impregnating the same with an aqueous solution which contains at least 220 grams of sodium sulfate per liter of solution, and is substantially free of sodium chloride, thereafter impregnating the thus relaxed tow at a temperature up to C. with an aqueous formaldehyde solution having a pH of between 4 and 7 which contains at least 210 grams of sodium sulfate per liter of solution and is substantially free of sodium chloride and thereafter impregnating the tow at a temperature between 70 and 98 C. in a strongly acidified. aqueous formaldehyde solution containing, per liter of solution, at least 340 grams of sodium sulfate, at least 15 grams of sodium chloride and at least 200 grams of sulfuric acid said process taking from one to thirty minutes.

2. A process of insolubilizing at least until the filaments do not dissolve in a bath containing 0.1% sulfuric acid and 0.25% sodium sulfate when immersed therein for minutes at 97 C., under conditions substantially free from tension, a continuous travelling tow of protein filaments obtained by spinning aqueous alkaline solutions of proteins selected from the group consisting of vegetable seed globulins and phospho-proteins into a sulfuric acid-sodium sulfate coagulating bath, said process comprising the steps of relaxing said tow of coagulated filaments by impregnating the same with an aqueous solution which contains 220 grams of sodium'sulfate per liter of solution, and is substantially free of sodium chloride, thereafter impregnating the thus relaxed tow at a temperature between 40 and 80 C. with an aqueous formaldehyde solution having a pH of between 4 and 7 which contains 210 grams of sodium sulfate per liter of solution and is substantially free of sodium chloride and thereafter impregnating the tow at a temperature between 70 and 98 C. in a strongly acidified aqueous formaldehyde solution containing, per liter of solution, 340 grams of sodium sulfate, 15 grams of sodium chloride and 200 grams of sulfuric acid said process taking from one to. thirty minutes.

3. The method of claim 1 wherein the aqueous formaldehyde solution which contains at least 210 g. sodium sulphate per litre of solution has a temperature of between 40 and 80 C.

4. The method of claim 1 wherein the said strongly acidified formaldehyde solution is used at temperatures between 90 and 98 C.

sufficientf toinsolubilise the protein filaments 5. The method-of claim [wherein the'tre'ating solutions preceding the said strongly acidified Referencee Cited in the file o this patent UNITEDYSTATES PATENTS Number 1 Name i Date;

2,533,297 Thomson Dec. 12, 1950 2,565,908 Campbell et a1 Aug. 2a, 1951 Tetlow Aug. 28, 1951 FOREIGN PATENTS Country Date Great Britain Sept. 21, 1939 Great Britain Jan. 27, 1948 Great Britain May 18, 1949 OTHER REFERENCES Journal of Society of Dyers and Colorists, June 1945, pages 150 to 155.

Claims

1. A PROCESS OF INSOLUBILIZING AT LEAST UNTIL THE FILAMENTS DO NOT DISSOLVE IN A BATH CONTAINING 0.1% SULFURIC ACID AND 0.25% SODIUM SULFATE WHEN IMMERSED THEREIN FOR 90 MINUTES AT 97* C., UNDER CONDITIONS SUBSTANTIALLY FREE FROM TENSION, A CONTINUOUS TRAVELLING TOW OF PROTEIN FILAMENTS OBTAINTED BY SPINNING AQUEOUS ALKALINE SOLUTIONS OF PROTEINS SELECTED FROM THE GROUP CONSISTING OF VEGETABLE SEED GLOBULINS AND PHOSPHO-PROTEINS INTO A SULFURIC ACID-SODIUM SULFATE COAGULATING BATH, SAID PROCESS COMPRISING THE STEPS OF RELAX-