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
  • D01F2/10—Addition to the spinning solution or spinning bath of substances which exert their effect equally well in either

Definitions

• This invention relates to the regeneration of cellulose from viscose. More particularly, it relates to a new process for manufacturing regenerated cellulose articles such as filaments or films having improved properties.
• An object of this invention is to provide a process or" manufacturing regenerated cellulose filaments having gel swelling values lower than heretofore attainable by methods known to the art and exhibiting considerably improved yarn properties. Another object is to provide a process whereby unripened viscose can be spun in conventional spinning equipment to give yarn of high quality. A further object is to provide a process of manufacturing regenerated cellulose yarn having entirely novel and desirable properties. Yet a further object is the provision of a method of producing a high-tenacity regenerated cellulose fiber having a non-crenulated surface. Another object is producing very high-strength yarns having smooth (non-crenulated) surfaces with improved soil resistance and abrasion resistance. Other objects appear hereinafter.
• a viscose solution into a coagulating bath comprising an aqueous solution of sulfuric acid and from 1% to 15% of zinc sulfate, the ex truding being conducted in the presence of about 0.01% to about 1%, by weight of one of said solutions, of a diamine soluble in 6% aqueous sodium hydroxide to the extent of at least 0.2% by weight, said diamine containing a total of at least three carbon atoms and having its amino groups attached to aliphatic carbon atoms, the amino groups being separated by a chain of only carbon atoms, any mouovalent substituent on the amino nitrogens being alkyl groups of l to 6 carbon atoms.
• the gel thread is collected in a monolayer on a bobbin, by manually operating a traverse mechanism with the thread being stretched 100-120% in a secondary (hot dip) bath.
• the sample is centrifuged (1400 rpm.) for a minute, cut oil, and weighed in a closed bottle.
• the sample is washed free of acid, dried in an oven at 105 C., and weighed.
• the ratio of gel weight to cellulose weight (grams of gel per gram of cellulose) is referred to as the gel swelling. Variations may be introduced in the procedure, e.g., in the stretch, spinning speed, or length of bath travel, but these introduce only minor changes in the numerical values of gel swelling. In the case of films, excess bath is removed by blotting with pulp sheet and the gel swelling value is expressed as for filaments.
• D value Another important indication of yarn quality is the factor referred tobelow as D value.
• This factor relates to the rate of neutralization of the viscose filament in the coagulating and regenerating bath. It is determined by adding to the viscose a suitable indicator, in this case bromocrjesol purple (pH range 5.2-6.8), and observing the distance in inches from the spinneret at which the purple color completely disappears in the traveling filament. This distance is the D value.
• a suitable indicator in this case bromocrjesol purple (pH range 5.2-6.8)
• the caustic content of the viscose refers to the total alkalinity expressed as sodium hydroxide. It includes free sodium hydroxide and that combined in theform of sodium carbonate, sodium tri'- thiocarbonate, and sodium cellulose xanthate.
• Viscose containing 0.02% by weight of hexamethylenedlamine (0.17 millimole per 100 g. of viscose) is pre pared as follows, using 5% cellulose and 6.5% sodium hydroxide: alkali cellulose aged to get the desired viscose viscosity (30-60 pois es) is xanthated for 3 hours using 43% carbon disulfide (based on the recoverable bone-dry cellulose). The xanthate crumbs are dissolved 1n a solution of sodium hydroxide containing hexamethylenediamine in the amount calculated to give the proportlon mentioned above.
• the freshly prepared viscose is filtered while it is cold, deaerated, and kept at 0 C. until spun, i.e.; it is spun in the unripened state and has a high salt index value, high xanthate sulfur content, and fairly low sodium trithiocarbonate content.
• the viscose is converted to a 1100 denier-650 filament yarn by extruding through a spinneret having holes of 0.0025" diameter into a primary coagulating and regenerating bath comprising 8% sulfuric acid, 17% sodium sulfate and 10% Zinc sulfate.
• the yarn is given a bath travel of 40 inches byusing a roller guide.
• the apparatus and general procedure used to lead viscose into the bath and to collect the formed thread are essentially the same as those used commercially in the so-called bobbin or spool process.
• the specific conditions include a bath temperature of 62 C. and the filaments are carried through a secondary bath of 2% sulfuric acid at 95-100" C.
• the yarn is wound on a bobbin at 28 r.p.m. with a stretch of approximately 110% beyond the pri mary bath.
• the resulting regenerated gel yarn is Washed free of acid and salt and then processed.
• the yarns are slashed dry at sufiicient stretch to produce elongation of cords at 10 lb. load of 7-10%. Yarns and cords are tested after conditioning at 76 F. (24.5 C.) and 56% relative humidity for 48 hours.
• the properties of the yarn and cord prepared from this viscose are listed in the accompanying table together with those for an unmodified control viscose. It will be seen that the yarn prepared from viscose containing hexamethylenediamine has a lower gel swelling value and a higher D value than the control. Its wet tenacity and elongation are higher than the control. Perhaps the most significant improvement is the substantial increase (0.41 g./den.) in the conditioned cord tenacity. This increase reflects a considerable improvement in the product, particularly for use in tire cords.
• the yarns produced by this and the other examples have a number of physical properties which distinguish them sharply from. other regenerated cellulose yarns. These properties are similar to those of the yarns produced through modification of viscose with short-chain quaternary ammonium compounds and selected amines which are described in the Cox U.S. Patents Nos. 2,536,- 014, 2,535,044 and 2,535,045. The most readily apparent modifications are the cross-sections and surface features. For yarns prepared from; unmodified viscose spun into zinc baths, a skin or outer shell which swells to a different extent in water from that of the core is visible. These yarn cross-sections show both deep and shallow crenulations around the contour of the filament.
• the properties of the yarn produced using the latter two modifiers are comparable to the properties of yarn obtained using hexamethylenediamine.
• the yarn properties of these filaments show improvements similar to those obtained by the use of hexamethylenediamine.
• EXAMPLE IV A viscose containing 0.9 millimole of N,N-diisobntylhexamethylenediamine (0.2%) per 100 grams of viscose is prepared using 7% cellulose, 6% sodium hydroxide and 35% carbon disulfide. This viscose is spun in the bath of Example II, along with an unmodified control viscose. The effects of the diamine added to 5 EXAMPLE VI the viscose on the D value, gel swelling and appearance Cotton linter viscose containing 7% cellulose, 6% of the cross-section of the filament are shown in the total alkali and 35% carbon disulfide is prepared as table below. described in Example II and spun in the unripened state Table IV into a coagulating bath containing 7% sulfuric acid,
• the coagulating bath contains 8% sulfuric factory results f the P p of this invention hi acid, 23% sodium ulfate and 4% zinc lf t Th requirement operates also when the diamine is used in exception is run 8, using 1,4-cyclohexanediamine, in the coagulating bath, since it should be noted that some which a bath of 6% sulfuric acid, 23% sodium ulfate diamines are practically insoluble in the normal coagulatand 4% zinc sulfate is used.
• N-methyltrlmethylenediamine 2.6 0.23 16 25 0.65 4.... N,N-dimethylethylenediamlne. 3.4 0.3 16 23 0.62 5...- Piperazine 3.5 0.3 15 16 0.88 6 N,N-dimethyltrimethylenediamine. 3.0 0.3 16 20 0.
• consodium hydroxide have generally been found to be also trol gel swelling ratio is 1.0, no reduction being involved soluble in coagulating baths. and the gel swelling ratio, the ratio of the gel swelling In addition to the solubility requirement, the suitable factor of the modified sample to that of the unmodified, indicates the reduction gained in gel swelling by use of the specific modifiers of this invention.
• the use of diamines not belonging to the operable class such as ethylenediamines should contain at least three carbon atoms in the molecule.
• the amino groups should be attached to aliphatic carbon atoms only, that is, to carbon atoms which are not part of an aromatic nucleus or of a heterocyclic nucleus aromatic in character, and no atoms other than carbon should be present in the chain separating the amino groups, although other groups such as alkoxy, heterocyclic, aromatic or dialkylarnino groups may be attached as side chains to these carbon atoms.
• the amino nitrogen atoms are separated by at least two carbon atoms.
• the monovalent substituents, if any, on one or both of the nitrogen atoms should be alkyl, including cycloalkyl, groups of 1 to 6 carbon atoms.
• the preferred diamines for use in the process of this invention are the wholly aliphatic, including cycloaliphatic diamines which contain only carbon and hydrogen besides the two amino nitrogens and which have a total number of carbon atoms between 4 and 14, inclusive, in addition to fulfilling the other requirements discussed above. Still more preferred are the polymethylenediamines of 4 to 14 total carbon atoms having from 4 to 8 methylene groups between the amino groups, and their N-alkyl substituted derivatives where the N-alkyl groups have from 1 to 4 carbon atoms, inclusive.
• other suitable compounds include pentamethylenediamine, octamethylenediamine, N cyc'lohexyltetramethylenediamine, N,N-diallylhexamethylenediamine, N-methylnonamethylenediamine, N-hexyltrimethylenediamine, N,N-dimethylpiperazine, N-butylhexamethylenediamine and the like. Mixtures of two or more diamines can be used.
• the diamine may be used either in the viscose or in the coagulating bath or both, but much better results are in general obtained when it is used in the viscose, and this embodiment of the invention is therefore the preferred one.
• the solvent for the amine viscose or coagulating bath
• the solvent for the amine contain at least 0.01% of the diamine by weight. It is in general unnecessary to use more than 1% by weight of the modifying agent, a generally useful range being 0.02-0.5%.
• the diamine is used in the coagulating bath, it is in general desirable to use more of it than when it is present in the viscose, a suitable range of concentration in the bath being 0.2-1%.
• concentration for any given agent, whether in the viscose or in the bath, depends on its effectiveness and on its molecular weight. Perhaps a preferable manner of expressing the concentration is in terms of millimoles of diamine per 100 grams of solvent. Between 0.1 and 10 millimoles of diamine per 100 grams of viscose is a suitable range of proportions, although more can be used if desired and if the diamine is sufliciently soluble. In the coagulating bath, there can be used between 1 and 15 millimoles of diamine per 100 grams of bath.
• the optimum amount of diamine to be used also depends to some extent on process variables such as the spinning speed, since at the high spinning speeds used in industrial practice less agent is desired than at lower speeds, for the reason that the rate of neutralization of the filament should be retarded only to the extent compatible with complete coagulation during the short time the filament is in contact with the coagulating bath. Determination of the optimum concentration of the amino compound is a matter of simple experimentation for those skilled in the art.
• the viscose used in the process of the invention may be of a variety of types; for example, it may be from wood pulp, cotton linters, mixtures of the two, or even other types of cellulose.
• the composition of the viscose may also be varied widely. For example, it may have a cellulose content of from 4 to 10%, or even more, and an alkali content of from 4 to 8% or more.
• the standard viscoses of the industry, i.e., those having between 5 and 7% cellulose and between 4 and 6% alkali, are preferably used.
• the amount of carbon disulfide used in the xanthation can be from 25-5 0% (based on the recoverable bonedry cellulose). It has been found that higher than normal xanthate sulfur contents (higher salt indices) can be used in the viscose when the diamines described herein from 30 C. to 70 C. or higher.
• the spinning baths suitable for use in the invention contain sulfuric acid, usually sodium sulfate, and zinc sulfate.
• Zinc sulfate is an essential component of the spinning bath since, in its absence, or if it is present in insufficient amount, the amine compounds have no effect on spinning and yarn properties.
• additional salts of divalent metals known to reinforce or supplement the action of zinc sulfate may be used, such as ferrous sulfate, manganese sulfate, magnesium sulfate, nickel sulfate, or chromic sulfate, preferably ferrous sulfate. When one or any of these supplementary metal salts are used, smaller amounts of zinc sulfate are required.
• the spinning bath contains from 4 to 12% of sulfuric acid, from 13 to 25% of sodium sulfate, and from 2 to 15% of zinc sulfate; if ferrous sulfate is to be used, 1 to about 5% is normally added.
• diamines With the addition of diamines to the baths, it is possible to obtain excellent yarns in the upper range of bath acidity under which conditions normal, unmodified viscoses give yarns of decreased quality.
• the tem-- perature range of best spinnability is from 40 C. to 65 C.
• the viscose filaments may be extruded at temperatures of 15 C. to 30 C. or the viscose may be heated immediately prior to extrusion to temperatures ranging
• the filaments may be given a long travel of 130 to 250 inches in the primary bath by means of a multiple roller setup which gradually applies tension to the traveling filaments and thereby orients them while they are still plastic.
• the preferred method however,.is to apply a part or all of the stretch beyond the primary bath in a secondary bath or to use a combination of air and hot-bath stretch.
• the secondary bath may consist simply of water or of dilute (1% to 3%) sulfuric acid, or it may have the same composition as the coagulating bath but a greater dilution, e.g., onefourth of the concentration of the coagulating bath.
• the temperature of the secondary bath is preferably between 50 C. and C. Stretches of 80% to are preferred for producing high-tenacity yarn and 20% to 30% for textile type yarns.
• the bobbin process has been used in the example, but it is immaterial whether spinning is by bobbin, bucket, or continuous process. The yarn cake is washed free of acid and salt, then dried under tension. If preferred, it may betwisteror slasherdried to enable the dry elongation of the finished product to be controlled.
• the P ef d pr cedure s o d aw off the fr hly 9 coagulated gel yarn with a feed-wheel speed equal to or less than the jet velocity and to apply all of the stretch between positively driven rollers traveling at difierent speeds.
• the thread can be given a travel of to 50 inches in the secondary bath of hot water or dilute bath. As mentioned above, the amount of stretch applied depends on the properties desired for the yarn.
• Spinning may be carried out with the aid of spinning tubes such as described in Millhiser US. Patent 2,440,057 or in Drisch et al. US. Patent 2,511,699.
• These tubes of relatively small diameter and of substantial length confine the bath and filaments in their critical stage of formation so that no substantial tension is imposed on the filaments because the speed of the concurrent bath flow is maintained only slightly below the speed of the filament bundle passing through the tube. It is thus possible to increase materially the rate of spinning over methods earlier described without substantial sacrifice in the desirable properties set forth above.
• novel and improved yarns obtainable through the process of this invention have substantially improved physical properties such as wet tenacities and can, in general, be used instead of regular regenerated cellulose fibers for any purpose where the latter are finding applications, more particularly in the textile and tire cord industries.
• the invention is generally applicable to the preparation of filaments, yarns, films, caps, bands, ribbons, and other structures of regenerated cellulose. For convenience it has been discussed with particular reference to the production of viscose rayon yarn; other articles can be made using the information given to improve properties.
• a method of producing regenerated cellulosic structures which comprises extruding a viscose solution in a coagulating bath comprising an aqueous solution of sulfuric acid containing from about 1% to about zinc sulfate, said coagulating being conducted in the presence of about 0.01% to about 1.0%, by weight of one of said solutions, of an aliphatic amine containing two amino nitrogen atoms separated by at least two carbon atoms, containing a total of at least three carbon atoms, any monovalent substituent on an amino nitrogen atom containing no more than 6 carbon atoms and the said amine being soluble to the extent of at least 0.2% by weight in 6% aqueous sodium hydroxide.
• a method of producing regenerated cellulosic structures which comprises extruding viscose in an aqueous sulfuric acid coagulating bath containing from about 1% to about 15 zinc sulfate together with about 0.01% to about 1.0% by weight of said bath of an aliphatic amine containing only two amino nitrogen atoms separated by at least two carbon atoms, containing a total of at least three carbon atoms, any monovalent substituent on an amino nitrogen atom containing no more than 6 carbon atoms, and the said aliphatic amine being soluble to the extent of at least 0.2% by weight in 6% aqueous sodium hydroxide.
• a method of producing regenerated cellulosic structures which comprises extmding viscose in an aqueous sulfuric acid coagulating bath containing from about 1% to about 15% zinc sulfate, the said viscose containing about 0.01% to about 1.0% by weight of an aliphatic amine containing only two amino nitrogen atoms separated by at least two carbon atoms, containing a total of at least three carbon atoms, any monovalent substituent on an amino nitrogen atom containing no more than 6 carbon atoms, and the said aliphatic amine being soluble to the extent of at least 0.2%by weight in 6% aqueous sodium hydroxide.
• An aqueous sulfuric acid coagulating bath for the preparation of regenerated cellulosic structures from viscose, said bath comprising an aqueous solution of sulfuric acid with from about 1% to about 15% zinc sulfate with about 0.01% to about 1.0% by weight of an aliphatic amine containing only two amino nitrogen atoms separated by at least two carbon atoms, containing at least three carbon atoms, any monovalent substituent on an amino nitrogen atom containing no more than 6 carbon atoms, and the said aliphatic amine being soluble to the extent of at least 0.2% by weight in 6% aqueous sodium hydroxide.
• a bath in accordance with claim 8 which contains about 0.2% to about 1.0% of said amine.
• a bath in accordance with clain 8 which contains about 13% to about 25% sodium sulfate.
• Viscose containing about 0.01% to about 1.0% by Weight of an aliphatic amine containing only two amino nitrogen atoms separated by at least two carbon atoms, containing at least three carbon atoms, any monovalent substituent on an amino nitrogen atom containing no more than 6 carbon atoms, and. the said aliphatic amine being soluble to the extent of at least 0.2% by weight in 6% aqueous sodium hydroxide.
• Viscose having a salt index of at least 5 and containing about 0.1% to about 1.0% by weight of an aliphatic amine containing only two amino nitrogen atoms separated by at least two carbon atoms, containing at least three carbon atoms, any monovalent substituent on an amino nitrogen atom containing no more than 6 carbon atoms, and the said aliphatic amine being soluble to the extent of at least 0.2% by weight in 6% aqueous sodium hydroxide.
• composition in accordance with claim 11 in which said viscose is unripened viscose.
• composition in accordance with claim 12 in which said viscose is unripened viscose.
• composition in accordance with claim 13 in which said viscose is unripened viscose.
• Viscose containing about 0.01% to about 1.0% by weight of an aliphatic amine containing only two amino nitrogen atoms separated by at least two carbon atoms, containing at least three but no more than 14 carbon atoms and being soluble to the extent of at least 0.2% by weight in 6% aqueous sodium hydroxide.
• a method of producing regenerated cellulosic structures which comprises extruding a viscose solution in a coagulating bath comprising an aqueous solution of sulfuric acid containing from about 1% to about 15% zinc sulfate, said coagulating being conducted in the presence I?” amino nitrogen atoms. separated by at least two carbon atoms, containing a total of at least three carbon atoms, any monova'lent 'subst-ituent on an amino nirogen atom containing no more than 6 carbon atoms and the said amine being soluble to the extent of at least 0.2% by weight in 6% aqueous sodium hydroxide.

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  • NL NLAANVRAGE7805875,A patent/NL182650B/xx unknown
• 1953
  • 1953-11-09 GB GB30924/53A patent/GB762772A/en not_active Expired
  • 1953-11-10 FR FR1089684D patent/FR1089684A/fr not_active Expired
  • 1953-11-12 DE DEP10807A patent/DE1079787B/de active Pending
  • 1953-11-18 CH CH332762D patent/CH332762A/de unknown
  • 1953-11-30 BE BE524723D patent/BE524723A/xx unknown
• 1954
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