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

Definitions

• the application discloses a process for producing highly polymerized viscose rayon filaments having high loop and knot tenacity. Fibers of high viscosity are spun into a low acid concentration bath and before fixing in a hot acid bath are stretched either in air or in a separate bath. After stretching the fibers are introduced into a separate bath which has a temperature of from 30 to 80 C. and a pH of 8 to 10.5. As a modification, stretching occurs in a bath having a temperature of less than 30 C. and an acid concentration of at least 1.4 in terms of pH value.
• Such a fact may depend on the fact that in the high polymerization-low acid process strain is apt to result within the fibers and the strain is more easily fixed in the fibers in comparison with that which occurs in conventional viscose processes.
• Our applied process is characterized by the fact that the spun thread is treated, between its stretching stage and heat-setting stage, by water, a diluted solution of acid, or weak alkaline neutral-salt or a weak alkaline acidsalt whose pH is in the range from 1.4 to 105, being selected in conformity with the degree of development of the inner structure of the thread.
• the object of our invention is to provide improved fiber of highly polymerized rayon filament having high loop and knot tenacity without any deterioration of its so-called polynosic characteristics (hereinafter referred to as improving-effect).
• the spun thread is stretched immediately after leaving the spinning bath in order to increase the tenacity of the fibers. Therefore, in the high polymerization-low acid process, the stretching is applied at a relatively early stage of fiber formation, and the development of the fiber structure, that is, the hydrogen bonding, occurs mainly after the strecthing stage.
• the fiber structure changes from the stretching stage to the heat-setting stage. Therefore, the suitable conditions of the relaxing liquor must be chosen corresponding to its stage of the treatment. Practically speaking, he relaxing liquor must have such as intensity that it can relax the amorphous regions only but has no influence upon the crystal regions.
• the relaxing intensity is too low for the fiber structure, then the desired improvement will not occur and, if it is too high, then although the improvement is sutficient, the crystal regions may be disturbed, and various defects, for instance, the decreasing of the polynosic characteristics or the formation of sticky fibers will result.
• the stages of fiber developments after the spinning bath and prior to the heat-setting stage are threefold, viz fiber condition during the stretching stage and immediately after the stretching and after travelling a certain distance in the air after stretching.
• the threads must be treated by a diluted acid liquor whose pH-value is more than 1.27 in order to obtain the desired improvement.
• the acid concentration of the treating liquor should be lower than that of the liquor previously attached to the fibers. Then the acid concentration in the surrounding liquor of the fibers is lowered, and the fiber structure which has already developed corresponding to the liquor attached to the fibers shall be relaxed, and accordingly the strain which is to occur at the stretching is limited.
• the treating-liquor in this case must be acidic, and water or an alkaline liquor is too strong for the relaxation of the fiber structure, and accordingly the formation of the sticky-fibers or the deterioration of the polynosic characteristics may be caused.
• Table 2 a treating liquor that will not change the 'y-value of the threads should be used. This case is shown in Example 1.
• the threads must be treated by using water or a solution whose pH-value is 7 or thereabouts containing extremely small quantity of acids, alkalis, or salts. By the said treatment only the amorphous regions are relaxed and the desired improvement will be obtained.
• the desired improving-eifect is obtained by treating the threads using an alkaline solution whose pH-value is 8 to 10.5.
• the neutral salts or acid salts, whose aqueous solutions are alkaline are suitable as treating agents.
• acid salts as sodium bicarbonate or disodium hydrogen phosphate exhibit an excellent improving-effect in a certain concentration range without causing any damage to the polynosic characteristics of the fibers.
• the pH-value of the sloutions of such acid salts is nearly constant irrespective of their concentration, as shown in Table 4.
• the relaxing-ability has no relation to their concentration, because the relaxing-ability depends mainly on the concentration of the hydroxyl ions (pH-value).
• the presence of the salts is antagonistic to the relaxing action of the hydroxyl ions hereinafter referred to as the salt-effect.
• the range of relaxing effect is rather limited up to in the relatively lower-ordered regions Where the strains are accumulated.
• the formation of the sticky fibers is also restrained in proportion to the salt concentration.
• caustic soda solution or ammonia water indicates a high pH value even in low concentration, and with these agents the suitable pH value for the relaxing treatment can be attained at extremely low concentration, so that the salt-effect can not be expected from such caustic alkalis. Therefore, damage to the polynosic characteristics occur under conditions where strain is eliminated from the fibers. For that reason, caustic alkalis are not desirable in the process.
• sodium carbonate or sodium silicate presents some danger on account of their fairly strong alkali content although they are neutral salts. But it is not so unfavorable as caustic alkalis.
• Example 6 The process employing the multi step treatments at succeeding time periods is also possible.
• the process using the two-step treatment is 'shown in Example 6, and that of the three-step treatment is shown in Example 7.
• Table 1 there is shown a comparison of the improving-effect during or at the end of the several stages of operation.
• R is an alkyl radical having more than twelve carbon atoms
• R R and R are one of the following radicals, i.e. methyl, ethyl, hydroxymethyl, and hydroxyethyl radicals
• X is halogen or sulphate radical.
• the addition from 0.3 g. to 1.0 g. of dimethyl stearyl hydroxyethyl ammonium chloride to 1 litre of the relaxing liquor is distinctly effective.
• the outer layer of regenerated cellulose makes a harder structure due to stretching in comparison with the corresponding structure of the conventional viscose process.
• This hard structure of the outer layer completely overcomes the contraction force of the inner layer which occurs as a result of the hot bath treatment. As a consequence, the contraction force of the inner layer produces a strain within the fibers.
• Viscose having a ball-falling viscosity of 420 sec. and 'y-value of 63 is spun at 30 C. in a spinning bath containing 17 g./l. of sulphuric acid, 60 g./l. of sodium sulphate, and 0.5 g./l. of Zinc sulphate.
• the spun threads are led to the stretching device after passing through guides and a drawing roller.
• the concentration of sulphuric acid in a liquor attached to the fibers at the entrance of the stretching device is 11 g./l. (pH 1.27).
• the threads While being stretched on the stretching device, the threads are treated by various liquids having the acid content shown in the 1st column of Table 2 and a temperature shown in the 4th column of Table 2. The results are shown in Table 2 in comparison with the nontreated fibers.
• EXAMPLE 4 A viscose having a high viscosity and a high -y-value is spun in a low acid concentration bath. After the stretching, the toW is cut to the desired length. The cut fibers are treated at various temperatures by a liquor containing 3 g./l. of NaHCO and are successively treated at 90 C. passing through a hot acid bath containing 3 g./l. of sulphuric acid to fix the inner structure of the fibers.
• a viscose same an Example 2 is spun at 30 C. in a spinning bath containing 18.5 g./l. of sulphuric acid, g./l. of sodium sulphate, and 0.45 g./l. of zinc sulphate. After the stretching on the stretching device the threads are cut to desired length. The cut fibers are treated at 55 C. for 5 minutes by liquids containing various quantities of Na HPO and are successively treated at 85 C. passing through a hot acid bath containing 3 g./l. of sulphuric acid to fix the inner structure of the fibers.
• EXAMPLE 7 A viscose having a full-falling viscosity of 450 sec. and a 'y-value of 72 is spun at 31 C. in a spinning bath containing 18.4 g./l. of sulphuric acid, 60 g./l. of sodium sulphate, and 0.4 g./l. of zinc sulphate.
• the tow is treated on the stretching device at 16 C. by a liquor containing 3.1 g./1. sulphuric acid and 0.3 g./l. of dimethyl stearyl B-hydroxyethyl ammonium chloride, and are successively treated by an aqueous liquor containing 0.5 g./l. of the above-mentioned surface active agent.
• the cut fibers are treated at 40 C. for 2 minutes by a liquor containing 3 g./l. of Na HOP and are immediately treated at 90 C. on passing through a hot acid bath to fix the inner structure of the fibers.

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• 1965
  • 1965-09-10 NO NO159660A patent/NO117649B/no unknown
  • 1965-09-16 FI FI2219/65A patent/FI43216B/fi active
  • 1965-10-11 AT AT918665A patent/AT283578B/de not_active IP Right Cessation
  • 1965-10-11 DK DK520065AA patent/DK120608B/da unknown
  • 1965-10-19 GB GB44324/65A patent/GB1082899A/en not_active Expired
  • 1965-10-20 BE BE671154D patent/BE671154A/xx unknown
  • 1965-10-25 CH CH1468465A patent/CH497555A/de not_active IP Right Cessation
  • 1965-11-02 NL NL6514182A patent/NL6514182A/xx unknown
  • 1965-11-26 ES ES0319358A patent/ES319358A1/es not_active Expired
• 1969
  • 1969-01-31 US US795680*A patent/US3632721A/en not_active Expired - Lifetime
  • 1969-01-31 US US795682*A patent/US3632723A/en not_active Expired - Lifetime
  • 1969-01-31 US US795681*A patent/US3632722A/en not_active Expired - Lifetime

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