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
  • D01F2/00—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof
  • D01F2/06—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof from viscose
  • D01F2/08—Composition of the spinning solution or the bath

Definitions

• This invention relates to the production of regenerated cellulose filaments from viscose and in particular to a process for the production of filaments having a high ratio of wet to dry tenacity, low extensibility, no skincore differentiation and low water-imbibition.
• the present process differs from the basic viscose rayon process in the following respects (1)
• the necessary length of the immersion path varies with the denier of the filaments being spun.
• the invention accordingly consists in a process for the production of viscose rayon filaments comprising extruding viscose having a cellulose content between 4 and 6 percent and a caustic soda content approximately half that of the cellulose, the cellulose having an average degree of polymerisation of at least 300 and the viscose having a salt figure of at least 10 and a ball fall viscosity of at least 50, preferably between and 200, into a coagulating bath containing from 2.0 percent to 3.5 percent of sulphuric acid, less than 15 percent and preferably between 1 percent and 10 percent sodium sulphate, and not more than 0.02 percent of zinc sulphate as an impurity, maintaining the bath temperature between 20 C.
• the required inmiersion path of the filaments in the bath varies with the denier of the filaments.
• the immersion path should not exceed 6 inches and it is preferred for fila: ments having deniers of 3 or less that the immersion path should not exceed 3 inches.
• the filaments can then be washed, dried and collected in a continuous form, or cut to produce a staple fibre, and subsequently washed and dried. Regeneration can be accelerated by treating the fibres at a suitable stage with warm dilute acid for example 2 percent of sulphuric acid at a temperature of 60 C.
• the amount of sulphuric acid in the regenerating bath is kept within the stated range of 2.0 to 3.5 percent and it is preferably just sufiicient to secure adequate coagulation.
• the actual amount varies with the number of filaments, the filament denier, spinning speed and the sodium sulphate concentration in the bath.
• the highly oriented filaments of low extensibility can be made into fabrics having good dimensional stability and this is mainly due to the low imbibition of the filaments and their high initial wet modulus, that is the markedresistance of the wet fibres to stretch under low loads.
• the fabrics show reduced relaxation shrinkages and greatly reduced or eliminated progressive shrinkages.
• Example 1 A high quality wood pulp such as that sold under the trade name Cordenier J. was steeped in an 18.6 percent aqueous solution of caustic soda for 1 /2 hours at 19 C. The surplus solution was removed by squeezing the pulp to a press ratio of 2.8 and the pulp was then disintegrated into'crumbs for 2 /2 hours at 19 C. after which the crumbs were allowed to age for -17 hours at the same temperature. The alkali cellulose was then xanthated for 3 hours with 42 percent of carbon disulphide (calculated on the original alpha-cellulose content of the wood pulp) at 24 C. and the resulting xanthate was mixed in a water-cooled vessel at 15 C. The mixing time was 3 hours during which the temperature rose to :17 C. A further 10 percent of carbon disulphide (also based on the alpha-cellulose) was then added in the mixer and the viscose was then filtered, deaerated by a flash deaeration process andleft to age for 12 hours in vacuum.
• the viscose containing percent of cellulose, 2.4 percent of caustic soda and 2.1 percent of sulphur and at a salt figure of 15, was then extruded at a ball fall viscosity of 100 seconds at 18 C. into a regenerating bath containing 2.7 percent of sulphuric acid and 1 percent of sodium sulphate at a temperature of 20 C.
• the viscose was extruded vertically upwards into the bath through a jet the face of which was about 1 /2 inches below the surface.
• the filament bundle travelled vertically upwards through the bath and then a distance of inches through the air onto two skewed sets of concentric discs of diameters 5, 6, 7, 8 and 9 inches respectively, giving 80 percent stretch for four stages. From the last disc the bundle was taken up on a roller and was stretched a further 17 percent between the last'disc and the roller. It was then passed through a hot fixing bath containing 2 percent of sulphuric acid at a temperature of 90 C. in which it was stretched a further 3 percent. After washing and drying, the filaments had the following properties:
• the crosssection of the filaments was circular and no differentiation between skin and core could be detected upon staining.
• Example 2 Viscose prepared as inExample l was spun through 3 mil diameter holes into a bath containing 2.5 percent of snlphuric acid and 5.3 percent of sodium sulphate at a temperature of 23 C., the immersion being two inches. The thread wasstretched a total of 100 percent in two stages and was then fully regenerated, washed, dried and collected. The final spinning speed was 50 metres per minute.
• the filaments produced had the following properties:
• the cross-section was circular and showed no skincore differentiation on staining.
• Example 3 spinning speed being. m./rninute.
• the filament denier was 1.5 and the average properties of randomly chosen filaments were:
• Example 4 and the denier 1.5.
• the filaments were cut to a staple length of 1 inches, Washed and dried.
• the average properties of the fibres were:
• the staple fibres were spun into a yarn of 1/l8s cotton count which was woven into a cloth of construction 64 ends/54 picks. 10 pounds of this cloth was washed in soap at 60 C. in a rotary washing machine for 30 minutes, rinsed for 5 minutes at 40 C., rinsed again for 10 minutes at 40 C., hydroextracted and dried in a tumbler drier. The laundering cycle was repeated at number of times and the dimensions of the cloth measured at intervals. The results are shown in the following table.
• Percent shrinkage Water imbibi- Wash tion (percent on weight Warp Weft of fabric) 1 loose dried 1. 4 4. 0 +1. 2 l. 4 4. 2 1. 8 0. 6 1.0 4. G 5.0 1. 0 1. 8
• the properties of the fabric are equivalent to or better than cotton in a cloth of the same construction and are much improved compared with normal viscose rayon textile fibres in a cloth of the same construction.
• a process for the production of viscose rayonfilaments comprising extruding viscose having a cellulose content between 4 and 6 percent and a caustic soda content approximately half that of the cellulose, the cellulose having an average degree of polymerization of at least 300 and the viscose having a salt figure of at least 10 and a ball fall viscosity between about 50 and about 200 seconds at 18 G, into a coagulating bath containing from 2.0 percent to 3.5 percent of sulphuric acid, less than 15 percent sodium sulphate, and not more than 0.02 percent of zinc sulphate as an impurity, to form filaments, maintaining the bath temperature between 20 C.

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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)

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Citations (3)

• 0
  • BE BE581631D patent/BE581631A/xx unknown
• 1958
  • 1958-08-12 GB GB25838/58A patent/GB915803A/en not_active Expired
• 1959
  • 1959-07-30 US US830477A patent/US2997365A/en not_active Expired - Lifetime
  • 1959-08-05 DE DEC19556A patent/DE1129656B/de active Pending
  • 1959-08-12 FR FR802697A patent/FR1232234A/fr not_active Expired

Patent Citations (3)

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