Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F4/00—Monocomponent artificial filaments or the like of proteins; Manufacture thereof

Definitions

• This invention relates to the production of regenerated p'ortein threads, fibres, filaments and the like, hereinafter generally referred to as threads.
• the invention may be applied for example to the production of threads from milk, or lactic, casein, peanut protein, 'soya bean protein or castor bean protein. 7
• Chromium salts are known to have a pronounced hardening and insolubilising action on protein threads but they have not been used very widely on a commercial scale; before the chrome treatment can be carried out, the other salts used in coagulating and/ or hardening must first be washed out of the thread.
• the object of this invention is an economic process for chrome-treating protein fibres.
• a process for the production of regenerated protein threads comprises extruding an aqueous alkaline solution of a protein through a jet into an acid coagulating bath in which is dissolved a trivalent chromium salt so that the bath contains the equivalent of at least grams per litre of Cr O stretching the resultant thread at least 100 percent in a salt bath at a temperature of at least 50 C. containing a trivalent chromium salt and hardening the stretched thread in a salt bath also containing a trivalent chromium salt.
• the coagulating bath used contains an acid which will in general be sulphuric acid. It also contains one or more salts such as sodium sulphate and/ or aluminium sulphate which have an astringent action on the thread and so prevent it swelling and possibly disintegrating when in contact with aqueous baths.
• the bath should contain at least 10 grams per litre of Cr O present as a trivalent chromium salt but it is preferred to use higher concentrations of for example 25 to 50 grams/litre.
• the coagulating bath may be at any temperature from ordinary temperature to about 50 C.; the preferred temperature range is 38 to 43 C. Temperatures much higher than 50 C. are preferably avoided as they tend to lead to blebbing at the jet and stuck filaments.
• a convenient coagulating bath is one of specific gravity 1.237 at 40 C. containing 200 grams/litre of Na SQ; (i.e. anhydrous), 40 grams/litre of Cr O added in the form of Cr O(SQ and 40 grams/litre of sulphuric acid.
• the stretching bath preferably has the same composition as the coagulating bath with the exception that the acid content is reduced; about 10 grams/ litre of sulphuric acid is preferred.
• the temperature of the bath must be at least 50 C. and temperatures of 60 to 65 C. are preferred.
• a suitable stretching bath has the composition 200 grams/litre of Na SO 40 grams/litre of Cr O and 10 grams/litre of sulphuric acid, this bath being used at 65 C. In a continuous run, care must be taken to adjust the composition of the bath as a result of carry-over of acid by the thread from the coagulating bath. Stretching may be effected by any known means such as by rollers of progressively increasing speeds.
• the hardening bath may have the same composition as that of the stretching bath but this is not-essential.
• the chromium content may; be increased and the content of the Na SO may begg reduced;
• the bath may be at any temperature but raised temperatures are preferred so as to accelerate the hardening reaction.
• the bath may also contain other hardening agents such as formaldehyde but this is not essential.
• the stretching and hardening baths contain one or more salts such as sodium sulphate and/ or aluminum sulphate which have an astringent action on the thread.
• stretching and hardening is preferably the same, thereby simplifying making up of the solutions and also facilitating recovery.
• a heat-stabilising step is introduced between the stretching and hardening stages.
• the heat stabilising process consists in holding the threads under tension, but without stretching, for up to one minute in one or more salt baths containing a trivalent chromium salt at a temperature of at least 60 C.
• the heat stabilising bath may conveniently be the same as that used in the stretching stage.
• Such a heat stabilising step serves to allow the fibres to absorb chromium and become cross-linked and hence more stable.
• a suitable stabilising treatment may be fore 9 seconds at C. followed by 9.5 seconds at C., the thread during the treatment being held under tension, but without stretching, between rollers rotating at equal speeds.
• any of the water-soluble trivalent chromium salts may be used, for example chromium sulphate, chrome alum or basic chromium sulphate.
• basic chromium sulphate allowance must be made in making up the baths for the sodium sulphate which it contains.
• Treatment of long lengths'of continuous threads may conveniently be effected using the plaiting method de-' scribed in United States Patent No. 2,3 83,358.
• the threads obtained by the present invention contain chemically combined chromium and have a marked resistance to hot liquids but, if desired, the threads may be subjected to a further hardening treatment with or without a chromium salt, or a known insolubilising process such as a cyanate treatment as described in United States Patent No. 2,684,282.
• the combined chromium improves the fire resistance of the threads.
• Water imbibition is a measure of the degree to which water is taken up by the threads.
• the term is well known in the art and is defined, for example, in my prior Patent 2,691,568, granted October 10, 1954, as the percentage by weight of water retained on the oven-dried fiber after centrifuging a 0.5 g. sample for 5 minutes at 1000 g.
• Example 1 A dispersion of 18 percent of lactic casein in 1 percent aqueous caustic soda solution was extruded into a coagulating bath at 40 C. containing, in each litre, 150 grams of sodium sulphate, 40 grams of sulphuric acid,
• the threads obtained were pale blue in colour and showed a good resistance to boiling dilute acid and mild alkaline solutions.
• Examples 2 to A dispersion of 18 percent of lactic casein in 1 percent aqueous caustic soda was extruded into a coagulating bath at 43 C. containing in each litre 200 grams/litre of Na SO (including 25 grams from the commercial chromium sulphate, green liquor), 40 grams/litre of Cr O as basic chromium sulphate and 40 grams/litre of sulphuric acid.
• the threads so produced were then stretched 800 percent in a bath at 65 C. containing 200 grams/litre of Na SO 40 grams/ litre of Cr O and grams/litre of sulphuric acid.
• the threads were then heat-stabilised on two pairs of even-speed rollers for 9 seconds and 9.5 seconds respectively, the first pair of rollers rotating in the stretch bath liquor at 80 C. and the second pair in the same liquor at 90 C.
• the heat-stabilised threads were then subjected to hardening treatments as follows:
• Example 2 The threads were hardened by immersion for 1 /2 hours in a bath at 65 C. having the same composition as the stretch bath liquor but with the addition of 20 grams/ litre of formaldehyde. The threads were then washed and dried. The Water imbibition of the product was 5 8.
• Example 3 The threads were hardened by immersion for 1 /2 hours in a bath at 65 C. having the same composition as the stretch bath liquor but with the concentration of the Na SO raised to 300 grams/ litre. The threads were then washed and dried. The water imbibition of the product was 71.
• Example 4 The threads were hardened by immersion for 30 minutes in a bath at 70 C. containing, per litre, 300 grams of Na SO 10 grams of sulphuric acid, 60 grams of crystalline aluminum sulphate, Al (SO l8H O, 40 grams of Cr O and 20 grams of formaldehyde. The threads were then washed and dried. The water imbibition of the product was 77.
• Example 5 The threads were hardened by immersion for 1 hour in a bath at 65 C. having the same composition as the bath used in Example 4 except that the Na SO content was reduced to 125 grams/litre. The threads were then washed and dried. The water imbibition of the product was 68.
• Example 6 The threads were hardened by immersion for 4 hours
• Example 7 A The threads were hardened by immersion for 2 hours in a bath at 65 C. containing, in each litre, 208 grams of Na SO 68 grams of Cr O 10 grams of sulphuric acid and 20 grams of formaldehyde.
• Example 8 The threads were hardened by immersion for 1 hour in a bath at 65 (3., containing, in each litre, 223 grams of Na SO 58 grams of Cr O 10 grams of sulphuric acid and 20 grams of formaldehyde. The threads, after washing and drying, had an imbibition of 67 and contained 1.6 percent combined chromium.
• Example 9 The spinning, stretching and heat-stabilising were carried out as described for Examples 2 to 5 and the heat stabilised threads were cut to staple lengths.
• the cut fibres were fed on to a conveyor belt and the hardening liquor described in Example 4 but at C. was continuously sprayed onto the moving fibres over a period of 20 minutes. The fibres were then washed and dried.
• a process for the production of regenerated protein threads which comprises extruding an aqueous alkaline solution of a protein chosen from the group consisting of lactic casein, peanut protein, soya bean protein and castor bean protein through a jet into a sulphuric acid coagulating bath in which is dissolved a trivalent chromium salt, stretching the resultant thread at least percent in a stretching bath at a temperature of at least 50 C., said bath containing a trivalent chromium salt and at least one salt chosen from the group consisting of sodium sulphate and aluminium sulphate and hardening the stretched thread in a hardening bath also containing a trivalent chromium salt and at least one salt chosen from the group consisting of sodium sulphate and aluminium sulphate, the coagulating, stretching and hardening baths each containing the equivalent of at least 10 grams per liter of Cr O 2.
• a trivalent chromium salt containing a trivalent chromium salt and at least one 'salt chosen from the group consisting of sodium sulphate and aluminium sulphate.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Artificial Filaments (AREA)
• Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=10235144

Family Applications (1)

Country Status (5)

Cited By (3)

Citations (3)

• 0
  • NL NL220038D patent/NL220038A/xx unknown
  • BE BE560157D patent/BE560157A/xx unknown
  • NL NL105941D patent/NL105941C/xx active
• 1956
  • 1956-08-24 GB GB25898/56A patent/GB805508A/en not_active Expired
• 1957
  • 1957-07-29 US US674586A patent/US2897044A/en not_active Expired - Lifetime
  • 1957-08-23 FR FR1181600D patent/FR1181600A/fr not_active Expired

Patent Citations (3)

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