Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
  • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F220/42—Nitriles
  • C08F220/44—Acrylonitrile
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F20/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
  • C08F20/02—Monocarboxylic acids having less than ten carbon atoms, Derivatives thereof
  • C08F20/52—Amides or imides
  • C08F20/54—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide
  • C08F20/58—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide containing oxygen in addition to the carbonamido oxygen, e.g. N-methylolacrylamide, N-acryloylmorpholine
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/22—Formation of filaments, threads, or the like with a crimped or curled structure; with a special structure to simulate wool
• • 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
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/28—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D01F6/38—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds comprising unsaturated nitriles as the major constituent

Definitions

• a fibre is composed of two chemically different polymers which occupy discrete collateral zones.
• the fibres are made by spinning the polymers side by side through each hole of a spinning jet.
• the polymers respond diflierently to heat, one shrinking more than the other, so that when the fibre is heated, it is drawn into a helical coil in which the more shrunken polymer follows the shorter path on the inside of the coil.
• a chemically homogeneous copolymer is extruded through an asymmetric jet hole in which the polymer is subjected to different amounts of shear across the hole.
• the extruded polymer is immediately coagulated to form a fibre which retains substantially the shape imposed by the jet-hole, and is stretched and dried under tension.
• the structure of this fibre is asymmetric in the physical properties of the polymer; that part of the polymer which was most highly sheared during extrusion is the most highly orientated and strained part of the fibre and, therefore, the part which shrinks most when the fibre is heated.
• This fibre too, assumes a helically coiled configuration when it is heated.
• a crimped or crimpable fibre according to the present invention is a fibre of a copolymer containing a major proportion of acrylonitrile and from 7 to 20 mol percent of an N-methylol or a latent N-methylol derivative of an ethylenically unsaturated acid amide.
• the amide derivative is preferably derived from acrylamide or methacrylamide.
• N-methylol acrylamide and N- methylol methacrylamide are examples of the derivatives comprising free methylol groups, but we prefer the latent N-methylol derivatives in which the hydrogen of the hydroxyl groups of the N-methylol group is replaced by an alkyl including a hydroxy alkyl group, or a secondary amino group, N(R) where R is alkyl, to reduce the chemical activity of the substance at near ambient temperatures, and increase the stability of the polymer during the stages of manufacture and spinning into fibres.
• the latent N-methylol derivatives must, however, be capable of interacting to cross link the polymer or of generating N-methylol groups which interact to cause cross linking at temperatures above those encountered in earlier process steps i.e. above about 100 C.
• the preferred, latent N-methylol derivatives are N (methoxy methyl) acrylamide and N (ethoxy methyl) acrylamide and the analogous derivatives of methacrylamide.
• the fibre may be made using wetor dry-spinning techniques, although a wet-spinning process is preferable, particularly one in which a solution of the polymer in concentrated sodium thiocyanate solution is extruded into water or dilute sodium thiocyanate solution to form fibres which are stretched by at least 500 percent in hot water or steam.
• the fibres may then be dried under tension to induce the stretch-strained character, or, after having been dried when relaxed the fibres may be strained by being stretched again.
• the stretched-strained fibres develop crimp, on being heated, preferably in contact with water or steam, to above their second order transition point which in all cases is less than 100 C.
• the spinning process can be made to yield crimped fibres directly if the never-dried fibres are dried under little or no tension.
• the polymer solution is homogeneous and may be extruded through circular jet holes so that no asymmetry is imposed mechanically on the fibre.
• the fibres of this invention are remarkable also for their ability to shrink when heated. Shrinkages of more than 40 percent and frequently as high as percent have been observed.
• the simultaneous shrinking and crimping which the fibres show when heated to above C. has a number of useful applications, amongst which are (i) the formation of a bulkier thread of crimped continuous filaments by the application of heat,
• the crimp can be eliminated from fibres which have been heated only long enough to develop the crimp, merely by stretching. However, it is possible to set the crimp in the fibres by cross-linking and the polymer requires no added reactant in order to do this.
• the N- methylol amide groups or latent N-methylol amide groups may be condensed intermolecularly to form methylene or dimethylene ether bridges. The condensation is catalysed by acids and some salts, for example those disclosed as catalysts for the reaction of cellulose and formaldehyde in British patent specification No. 930,132.
• an acidic monomer for example methallyl sulphonic acid
• a catalyst for the cross-linking reaction is incorporated to act as a catalyst for the cross-linking reaction.
• the cross-linking reaction requires that the fibre incorporating or impregnated with a catalyst is heated and, as heat is also required to develop the crimp, it is possible to combine both steps in a single treatment, particularly as the rate of crimping is so much more rapid than that of condensation reaction, that virtually all the cross-links are formed in the already crimped fibre.
• the crimp proves remarkably stable and is retained or regained during repeated cycles of washing and drying and cycles of tensioning and relaxing.
• Example 1 'A' polymerisation charge was made up of:
• the copolymer solution was extruded through a 20 hole jet, each hole having a diameter of 0.005 inch into a water bath at ambient temperature to form fibres.
• the fibres were stretched by 20 times in live steam, collected on a bobbin and dried.
• the fibres had an average denier of 4.4.
• the stretching step was modified after the collection of the first sample, to stretching the fibres in water at 87 C. by 12% times.
• the fibres from both stretching operations crimped instantaneously when relaxed in contact with a surface at 120 C.
• the fibres were cross-linked by first impregnating them with a 5 percent MgCl solution and finally heating them at 160 C. for 2 hours. When the fibres were relaxed and heated, the crimp was set by the cross-linking to the extent that it could not be removed by straining the fibres.
• the cross-linked fibres were also, insoluble in a wide variety of liquids, some of which were excellent solvents for the copolymer before cross-linking.
• Example 2 A mixture was formed of:
• the pH of the solution was adjusted to 6 with a sodium hydroxide solution and more water was added to bring the mixture to a total of 1,000 parts.
• the conversion of monomer to polymer was found to be 92 percent complete and the inherent viscosity of the polymer (in 50 percent w./w. aqueous NaCNS was 0.90.
• the viscous solution was extruded through a 20 hole jet, each hole having a diameter of 0.005 inch, into water at 4 C. to form filaments which were taken up at 2.5 m./m., stretched ten times in steam and collected.
• the still-wet filaments were subsequently washed with water, impregnated with an 11 percent solution of H PO in water and allowed to dry in air in a relaxed condition.
• the dry filaments were strongly crimped and possessed an asymmetric cross-section. At this stage the filaments could be dissolved in a 50 percent w./w. aqueous NaCNS solution and the crimp could be removed by tensioning the filaments in live steam.
• the fibre was only slightly swollen by the 50 percent NaCNS solution and the crimp could not be pulled out in steam.
• the cured fibre had a tenacity of 1.7 grams per denier and an extensibility of 28 percent.
• Example 3 A polymerisation process and extrusion identical with those described in Example 2, with the exception that the freshly-extruded filaments were stretched by only 5 times in water at 70 0., provided filaments which developed more crimp on air-drying in a relaxed condition.
• the filaments When the spinning process was altered so that the freshly extruded filaments were stretched by 24 times in steam and the filaments were cured in a relaxed state, the filaments acquired a tenacity of 3.28 grams per denier and an extensibility of 24 percent.
• Example 4 The polymerisation procedure of Example 2 was followed with a mixture having a pH of 6 and composed of:
• the extrusion was similar to that described in Example 2 with the exception that the freshly-extruded filaments were stretched by 26 times, soaked in a 1 percent aqueous solution of NH Cl, before drying in a relaxed condition in air.
• the dried fibre was highly crimped and could be cured by heating for 4 minutes at 150 C.
• Example 5 The polymerisation process disclosed in Example 2 was used to polymerise the monomers in a charge made up of:
• the resultant viscous solution was extruded through a 40 hole jet, each hole of 0.003 inch diameter, into water at 30 C.
• the filaments were taken up at 2.5 m./m., stretched 15 times in water at C., washed in dilute sulphuric acid and dried in a relaxed state at C.
• the filament crimped during the last step, but not to the extent of the filament made by following the procedure of Example 2.
• the filament had a tenacity of 1.07 and an extensibility of 43 percent.
• the filament After curing for 8 minutes at C., the filament had a tenacity of 1.72, an extensibility of 34 percent and an imbibition in 50 percent NaCNS of 23 percent.
• Example 6 The polymerisation process of Example 2 was followed in preparing a solution of a copolymer of 95 parts of acrylonitrile and 15 parts of N-methylol-acrylamide. The solution was extruded into Water at 12 C. to form filaments of circular cross-section which crimped spontaneously when dried relaxed. The filaments formed by extruding the solution into water at 4 C. did not crimp spontaneously.
• a fibre as claimed in claim 1 in a stretch-strained condition in a stretch-strained condition.
• a fibre as claimed in claim 1 in which the latent N-rnethylol derivative is chosen from the group consisting of N(methoxymethyl) acrylamide, N(ethoxymethyl) rnethacrylamide and N(butoxy methyl) acrylamide.
• a fibre as claimed in claim 1 incorporating at least 10 percent of the N-substituted amide and having a ribbon-like shape.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Health & Medical Sciences (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Textile Engineering (AREA)
• Mechanical Engineering (AREA)
• General Chemical & Material Sciences (AREA)
• Artificial Filaments (AREA)

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Cited By (4)

Citations (11)

• 0
  • DE DENDAT1251902D patent/DE1251902B/de active Pending
  • GB GB1084333D patent/GB1084333A/en active Active
• 1964
  • 1964-06-09 US US373876A patent/US3399177A/en not_active Expired - Lifetime
  • 1964-06-12 SE SE7214/64A patent/SE303171B/xx unknown
  • 1964-06-12 NL NL6406734A patent/NL6406734A/xx unknown
  • 1964-06-12 BE BE649236A patent/BE649236A/xx unknown
  • 1964-06-13 FR FR978215A patent/FR1398578A/fr not_active Expired
  • 1964-06-15 AT AT511564A patent/AT256328B/de active

Patent Citations (11)

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