Classifications

• • 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
  • D01D10/00—Physical treatment of artificial filaments or the like during manufacture, i.e. during a continuous production process before the filaments have been collected
• • 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
  • D01F11/00—Chemical after-treatment of artificial filaments or the like during manufacture
  • D01F11/04—Chemical after-treatment of artificial filaments or the like during manufacture of synthetic polymers
  • D01F11/06—Chemical after-treatment of artificial filaments or the like during manufacture of synthetic polymers of macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
• • 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
  • D01F6/02—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D01F6/18—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds from polymers of unsaturated nitriles, e.g. polyacrylonitrile, polyvinylidene cyanide
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
  • D06P3/00—Special processes of dyeing or printing textiles, or dyeing leather, furs, or solid macromolecular substances in any form, classified according to the material treated
  • D06P3/70—Material containing nitrile groups
  • D06P3/76—Material containing nitrile groups using basic dyes

Definitions

• This invention relates to improvements in methods for producing in-line dyed acrylic fibres, in which dyeing is implemented during a stage of the wet-spinning process.
• Dyeing an acrylic fibre during the spinning process falls within the known art, and its implementation depends on the particular morphology imposed on the fibre during spinning, this being desirably that of a finely distributed microporous structure.
• the fibre When such a structure of high unit surface area is imposed, the fibre is well suited for absorbing dyestuff solutions within a short time period such as to enable dyeing to be conducted continuously during the fibre production process itself, so avoiding the use of dyeing tanks of unusual dimensions.
• the colour tonality thus frequently varies according to the position of the filaments in the fibrous mass, the most outer fibres being more intensely and uniformly coloured than the inner fibres.
• document GB-A-816 841 describes a wet spinning process in which a solution of polyacrylonitrile in an aqueous solution of a salt is extruded into an aqueous solution of the same salt and the coagulated fibres are stretched, retracted in an aqueous medium which has been previously heated to 90°-100°C and has a superficial tension not higher than 30 dynes/cm, and then dried.
• the desired superficial tension is obtained by using a surfactant such as the dioctyl ester of the sodium-sulphosuccinic acid.
• a surfactant such as the dioctyl ester of the sodium-sulphosuccinic acid.
• the fibres Prior to being dried, the fibres are washed with acetone or another water-miscible liquid, to replace or to withdraw the aqueous medium which contains the surfactant.
• a constant and even colour hue especially if fibres dyed with dark colour hues are involved, is successfully obtained by subjecting the stretched fibres, before dyeing them, to a high temperature retraction, carried out in an aqueous bath, which is an aqueous solution of the same organic solvent (DMF, DMA or DMSO) as used for preparing the spinning solution and preferably also for the coagulation bath.
• an aqueous bath which is an aqueous solution of the same organic solvent (DMF, DMA or DMSO) as used for preparing the spinning solution and preferably also for the coagulation bath.
• the present invention provides for the preparation of dyed acrylic fibres by the wet-spinning process in which an acrylonitrile polymer is dissolved in a spinning solvent and the solution thus obtained is extruded through a spinneret in an aqueous coagulation bath and the coagulated (gelled) fibres thus obtained are stretched retracted in an aqueous liquor and dyed, said process being characterised in that the spinning solvent is a highly polar, aprotic organic solvent selected from dimethylformamide, dimethylacetamide and dimethylsulphoxide, and the aqueous liquor is an aqueous solution which contains from 10% to 80% by weight of dimethylformamide, dimethylacetamide or dimethylsulphoxide, said liquor being maintained at a temperature of from 100°C to 120°C to induce a retraction of the fibres of from 25% to 40%.
• the spinning solvent is a highly polar, aprotic organic solvent selected from dimethylformamide, dimethylacetamide and dimethylsulphoxide
• the stretched fibre is brought into contact with an aqueous solution of the organic solvent used for the polymer at a temperature of between 105 and 110°C, so as to induce an extent of retraction generally varying in the 30 to 38% range.
• the acrylic fibre attains an unexpectedly high dyeing capacity, so that is becomes simple to obtain fibres dyed with dark tones, even with relatively low dyestuff concentrations of the order of 20-30 g/l in the relative bath, and with short dyeing times generally of the order of 1-5 seconds.
• an economical advantage is also attained deriving from the reduced dimensions of the dyeing modules.
• Suitable acrylonitrile polymers for the purposes of the present invention are products of the copolymerisation of acrylonitrile with 5-10% by weight of a monomer generally chosen from methyl acrylate, methyl methacrylate and vinyl acetate. Particularly preferred are those acrylonitrile copolymers containing about 8% by weight of vinyl acetate. Conveniently, said acrylonitrile polymers have a means viscometric molecular weight of the order of 100,000-150,000.
• Said polymers are dissolved in a highly polar, aprotic organic solvent chosen from dimethylformamide, dimethylacetamide and dimethylsulphoxide, to form a solution (spinning dope) containing 10-30% by weight of polymer.
• a highly polar, aprotic organic solvent chosen from dimethylformamide, dimethylacetamide and dimethylsulphoxide.
• the solvent is dimethylacetamide and the spinning dope contains 20-28% by weight of polymer.
• the spinning dope obtained in this manner is degassed and filtered, and by means of a metering pump is then extruded through a spinneret into a coagulum bath.
• Spinnerets suitable for this purpose can contain 1,000-60,000 holes having a diameter of between 40 and 150 ⁇ m.
• the coagulum bath is a bath which does not dissolve the polymer but is able to extract the solvent from the spinning dope when this emerges from the spinneret holes.
• the coagulum bath consists of an aqueous solution of dimethylformamide, dimethylacetamide or dimethylsulphoxide, the preference being for the actual solvent used in preparing the spinning dope.
• the coagulum bath contains an organic solvent quantity of the order of 30-80% by weight, the operating temperature conveniently being 10°-60°C.
• Coagulation takes place under these conditions, with the formation of filaments which after leaving the coagulum bath can be grouped to form a tow of the desired grade.
• the coagulated fibre is then subjected to the usual stretching, to an extent generally within the 1:5 to 1:10 draft ratio range in the axial direction, and preferably of the order of 1:6-1:8.
• the stretched fibre is subjected to retraction treatment to obtain a degree of retraction of between 25 to 40% and preferably of the order of 30-38%.
• an aqueous solution is used containing about 60-65% by weight of dimethylacetamide, the operating temperature being of the order of 105-110°C.
• the retracted fibre is subjected to washing, which is conducted in countercurrent with demineralised water at a temperature of 80-100°C and preferably of the order of 90°C, to remove the residual solvent from the fibre.
• the washed fibre is dyed in dyeing baths containing a dyestuff or a mixture of several dyestuffs, in the form of an aqueous solution the concentration of which depends on the tonality to be obtained, and which for the darkest tones can reach values of the order of 30 g/l.
• Dyestuffs suitable for the purpose are cationic dyestuffs such as those of the azomethinic or azo type, or of the triphenylmethane class.
• dyestuffs are those known commercially as C.I. Basic Yellow, C.I. Basic Violet, C.I. Basic Red, C.I. Basic Blue and C.I. Basic Orange.
• the aqueous dyeing bath conveniently has a pH of the order of 3-5, the operating temperature being between 30 and 80°C, with contact times of between 1 and 5 seconds.
• dyeing tanks are generally used fitted with homogenising paddles and circulating pumps, the former moving at a speed of between 1 and 2 times the fibre speed, so as to subject the fibre to between 20 and 40 oscillations/sec/m.
• the fibre After dyeing, the fibre is wrung, and treated thermally with saturated steam at 100°C for about 10 seconds to complete dye fixing.
• the usual steps of washing to remove non-fixed dyestuff, lubrication with a solution of non-ionogenic products, drying and crimping then follow.
• Acrylic fibre is wet-spun in an industrial spinning line, with an hourly fibre production of 800 kg at a final rate of 50 m/min.
• a copolymer is used for this purpose containing 92% by weight of acrylonitrile and 8% by weight of vinyl acetate, and with a specific viscosity of 0.145 l/g.
• a solution containing 26% of the copolymer in dimethylacetamide is prepared. After degassing and filtering, this spinning dope is fed into a coagulum bath through spinnerets with 52 ⁇ m diameter holes.
• the coagulum bath in the form of an aqueous solution containing about 55% by weight of dimethylacetamide, is kept at 50°C and the formed filaments are grouped into various tows.
• the fibre is then stretched to a draft ratio of 1:6 in the axial direction, and is then subjected to retraction.
• This latter operation is conducted continuously in an aqueous bath containing 62% by weight of dimethylacetamide and kept at a temperature of about 106°C. Under these conditions, a retraction of 30% is obtained.
• the fibre is washed countercurrently at 90°C with demineralised water, and is then dyed continuously in a dyeing module consisting of a tank of about 2 metres in length fitted with two homogenising paddles each comprising six bars, and with a circulation pump.
• the fibre rate through the dyeing module is about 50 m/minute, and the dyeing time (defined as the time of contact of the fibre with the dyestuff solution) is 2.4 seconds, the paddle speed being 80 m/minute.
• the dyeing bath is kept at 70°C and comprises a 25g/l concentration of a dyestuff mixture consisting of C.I. Basic Yellow 28 (42% by weight), C.I. Basic Red 49 (14% by weight) and C.I. Basic Blue 41 (41% by weight).
• the dyestuff make-up feed into the dyeing tank is 40 l/hour, corresponding to 5% by weight of the fibre.
• the tows are wrung, treated thermally with saturated steam at 100°C for about 10 seconds in order to fix the dyestuff, washed in order to remove non-fixed dyestuff, lubricated with a solution of non-ionogenic products, dried, crimped and collected.
• the fibre also has the following characteristics: Count: 3.3 dtex Toughness: 25.4 CN/tex Ultimate elongation: 40.5% Shrinkage in water at 100°C: 2.5% Lubrication: 0.5%
• Example 1 The procedure of Example 1 is followed but omitting the retraction step.
• the instantaneous maximum dyestuff quantity contained in the fibre is 3.12% by weight, the percentage again referring to the liquid form of the commercial dyestuff used. Consequently, the fibre colour is distinctly lighter than that of the fibre of Example 1. Only when the dyeing bath concentration reaches 40 g/1 is a fibre obtained of colour equal to that of Example 1.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Artificial Filaments (AREA)
• Coloring (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (3)

Family

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Family Applications (1)

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• 1986
  • 1986-03-07 IT IT19668/86A patent/IT1204468B/it active
• 1987
  • 1987-02-13 IN IN96/MAS/87A patent/IN169210B/en unknown
  • 1987-02-23 EP EP87200306A patent/EP0241054B1/en not_active Expired - Lifetime
  • 1987-02-23 DE DE8787200306T patent/DE3781445T2/de not_active Expired - Fee Related
  • 1987-02-23 AT AT87200306T patent/ATE80187T1/de active
  • 1987-02-23 ES ES198787200306T patent/ES2035029T3/es not_active Expired - Lifetime
  • 1987-03-05 TR TR87/0186A patent/TR26243A/xx unknown
  • 1987-03-06 BR BR8701369A patent/BR8701369A/pt not_active IP Right Cessation
• 1992
  • 1992-09-30 GR GR920402182T patent/GR3005846T3/el unknown

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