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
  • D01F1/00—General methods for the manufacture of artificial filaments or the like
  • D01F1/02—Addition of substances to the spinning solution or to the melt
  • D01F1/04—Pigments
• • 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
• • 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
  • D01F6/40—Modacrylic fibres, i.e. containing 35 to 85% acrylonitrile
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M11/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising
  • D06M11/58—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with nitrogen or compounds thereof, e.g. with nitrides
  • D06M11/63—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with nitrogen or compounds thereof, e.g. with nitrides with hydroxylamine or hydrazine
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M2200/00—Functionality of the treatment composition and/or properties imparted to the textile material
  • D06M2200/30—Flame or heat resistance, fire retardancy properties

Definitions

• the present invention relates to a process for the production of fireproof polyacrylate fibre with a low emission of toxic fumes, uniformly dyed.
• the present invention relates to a process for the production of fireproof polyacrylate fi- bre with a low emission of toxic fumes, uniformly dyed, and to the fibre thus obtained.
• acrylic fibre from a copolymer are used in traditional textile fields such as clothing, home furnishing, flooring, etc.. or in the field of outdoor awn- ings.
• the acrylic fibre from a homopolymer, less diffused, is used for reinforcing concrete, for the filtration of fumes, etc..
• post-treatment of acrylic fibre which fully modify it, trans-forming it into products which are chemically very dif- ferent from the starting fibre and having new properties.
• the most well-known type of post-treatment is that which transforms the acrylic fibre into fireproof oxidized fibre, after thermal cyclization of the CN groups, or into carbon fibre through thermal treatment subsequent to oxidation and at higher temperatures, used in high- performance composite materials, such as high mechanical and thermal resistance.
• the properties shown by the fibre after this series of treatment are definitely of commercial interest, for example, for protective clothing, under extreme conditions of fire exposure, or for textile furnishings in environments in which fire-resistance and the absence of toxic fumes is essential (aeroplanes, trains, passenger ships, etc.. ) .
• this kind of fibre has a very limited diffusion on the market and is restricted to the production of non-woven fabrics to be used in multilayer materials as a fire-barrier.
• the reason for this low commercial diffusion can be found in the poor aesthetical appearance of the fibre which is pink or, when dyed, shows strongly irregular colours which discourage its use in the visible end-products produced, for example, in the clothes industry (working overalls) or furnishing (seat covers) .
• the reason for this dyeing irregularity lies in the irregular chemical composition and dyeing sites due to the post-treatment.
• the fibre must have a variation of dyeing sites not higher than 5% and this amount is assured by the constancy of the molecular weight of the polymer, if a redox catalyst of the persulphate-bisulphite type is used, or by the correct dosage of a sulphonated co- monomer, of the MASS (Sodium Methallyl Sulphonated) type, if catalysts of the AIBN azo-bisisobutyrronitrile) type are adopted.
• MASS sodium Methallyl Sulphonated
• the chemical treatment is carried out batchwise, on traditional dyeing equipment, by positioning the fibre in a perforated basket, and circulating the reagents through the fibre in sequence: reaction with hy- drazine, alkaline hydrolysis, neutralization with a strong acid, dyeing with pre-metallized dyes 1:1, salification with zinc acetate.
• the main drawback of this traditional process is that the fibre obtained can have an unacceptable variability in the chemical composition, after this treatment.
• a first variable is introduced by the irregular permeability of the fibre inside the basket, with a consequent non-homogeneous distribution of the modified CN groups .
• Another element which disturbs the homogeneity arises during the alkaline hydrolysis phase.
• the formation of carboxyl groups leads to an enormous swelling of the fibre which becomes like a gelatine, analogously to what occurs with super-absorbent polymers.
• the fibre in this phase, tends to expand but is prevented by the fact that it is blocked inside the basket.
• the subsequent phase consists of an acidification reaction with sulphuric acid, for example, of the carboxyl groups.
• sulphuric acid for example, of the carboxyl groups.
• Another function of the acid is to quaternize the amide and azide groups responsible for the dyeing proper- ties of the fibre. Some of the carboxyl groups are subsequently partly salified with metal ions, such as zinc, for example .
• acrylic fibres dyed with pigments offers another opportunity as, being free of dyeing problems, the reaction can be directed so as to privilege other fundamental properties of polyacrylate fibres, such as the mechanical characteristics, toughness and ultimate elongation, as well as the fire-resistance properties.
• pigmented fibre as precursor of polyacrylate fibres, reduces the treatment time by more than three hours, enhancing the productivity of the process.
• An object of the present invention therefore relates to a process for the production of fire-proof polyacrylate fibre with a low emission of toxic fumes, uniformly dyed, comprising: a. dissolving an acrylonitrile copolymer, for example acrylonitrile-vinyl acetate, in a solvent, for exam- pie dimethyl acetamide, in a weight ratio ranging from 90/10 to 99/1, for example 93/7, and having a number average molecular weight Mn ranging from
• the pigmented acrylic fibre can be used in the form of a staple or tow, bearing in mind the variation in length which will occur on the staple and the doubling of the titre on the tow at the end of the treatment .
• a solution with a concentration ranging from 23 to 28% by weight of solids, at 25.5% for ex- ample, of an acrylonitrile/vinyl acetate copolymer in a 93/7 ratio with the dispersion of the desired amounts of pigments, described above, is fed with a gear pump and with a volume flow-rate of 23.5 cm 3 /min. , to a 1,000 hole die, each hole having a diameter of 52 microns.
• the die is immersed in a coagulation bath containing a water/dimethyl acetamide solution in a 1:1 ratio at a temperature of 50 0 C.
• the cord of coagulated tows is extracted from the coagulation bath by a pair of rolls at a rate of 6.15 m/min.
• the fibre is contemporaneously washed with demineral- ised water to remove the solvent and passed through a tank containing boiling water, to be stretched in a ratio of 6.5:1 by a second pair of rolls having a peripheral rate of 40 m/min.
• the fibre After stretching, the fibre is immersed in a tub in which a finishing mix, having lubricant and antistatic properties, is fed in continuous. At the outlet of the finishing tank, the rope of fibres is collected on a pair of rolls having a peripheral rate of 40 m/min in differ- ent coils and heated with vapour up to a temperature of 160 0 C.
• the fibre rope thus obtained has a titre for each filament of 1.5 dtex and is collected on bobbins.
• Skeins are prepared from the bobbins obtained accord- ing to the procedures described above, in various coils having a diameter of a meter, and are treated in an autoclave with saturated vapour, at a relative pressure of 1.7 bar.
• the fibre undergoes a shrinkage of 30% with respect to the initial length and the titre of each fila- ment becomes 2.0 dtex.
• the fibre treated in the autoclave, uniformly dyed with the desired colours, has the following characteristics : titre 2.0 dtex toughness 32.5 CN/Tex
• step (d) the pigmented fibre is crosslinked with an aqueous solution of hydrazine hydrate at a concentration ranging from 5 to 25%, preferably from 7 to 20% (weight of hydrazine hydrate with respect to the volume of water) .
• the crosslinking is carried out at at- mospheric pressure, or slightly higher, at a temperature ranging from 70 to 150 0 C, preferably from 80 to 120 0 C.
• the fibre is treated with an alkaline aqueous solution, step (e) , for example with a solution of soda (NaOH) and/or potassium hydroxide, having a concentration of 1 to 8%, preferably from 3 to 6% (weight/volume) .
• the treatment with the alkaline solution takes place at atmospheric pressure, or slightly higher, and at a temperature ranging from 70 to 120 0 C, preferably from 80 to 110 0 C.
• the treatment with the alkaline solution is carried out for times ranging from 90 to 150 minutes, preferably between 100 and 130 minutes .
• the third fireproofing treatment, step (f ) comprises wetting the fibres with a strong inorganic acid, for example sulphuric, nitric, phosphoric or hydrochloric acid, diluted in water. Preferred concentrations range from 2 to 10%, for example from 3 to 8% (weight/volume) .
• the fibres remain in contact with the acid for a period of time ranging from 40 to 90 minutes, preferably between 50 and 70 minutes.
• This step is also carried out at atmospheric pressure, or slightly higher, but at temperatures ranging from 40 to 80 0 C, preferably from 50 to 70 0 C.
• the last fireproofing treatment step, step (g) comprises salification of the acidic groups present on the fibre with a metal salt, preferably an organic metal salt.
• a metal salt preferably an organic metal salt.
• This treatment is effected with an aqueous solution containing from 1 to 8% of the organic salt, preferably a metallic organic salt.
• This treatment is carried out with an aqueous solution containing from 1 to 8% of the organic salt, preferably from 2 to 5% (weight/volume) , operating at a temperature ranging from 80 to 120 0 C, preferably from 90 to 110 0 C, with a contact time ranging from 30 to 90 minutes, preferably from 45 to 70 minutes.
• Examples of said organic salts are zinc formate and/or acetate.
• the fibres are abundantly washed with hot water, centrifuged and possibly treated with a finishing product to eliminate the electrostatic charges and to impart feel softness.
• An illustrative and non-limiting example is provided hereunder for a better understanding of the present invention and for its embodiment.
• the tow of pigmented acrylic fibre which can be transformed into a staple on a cutting machine, is produced on industrial equipment according to the procedures described above and by pre-dispersing the above-mentioned pigments, individually or in a mixture, to reproduce the desired colour.
• the above-mentioned pigments are dispersed in the solution of the acryloni- trile/vinyl acetate copolymer at 25.5% in dimethyl acetamide, in such a concentration as to cover the pink/orange-coloured background that the raw fibre would acquire due to its new chemical composition, as a consequence of the crosslinking - hydrolysis - salification treatment .
• the basket is placed in a 2,000 litre reaction tank equipped with a circulation pump, in which the flow-rate and the functioning frequency can be programmed, and with a heating/cooling coil for the reaction liquid.
• the tank is filled with water and with a quantity of hydrazine hydrate so as to have a concentration in the liquid phase of 15% (weight/volume) .
• the solution is brought to 105 0 C and the circulation pump is kept in operation for 5 hours.
• the reacted hydrazine hydrate solution is discharged (concentration 9.7% equal to 0.30 kg of hydrazine hydrate per 1 kg of fibre) through a cool exchanger to bring the temperature of the solution to about 50 0 C.
• a soda solution is then charged in such a quantity as to have a concentration of 5% (weight/volume) in the liquid phase.
• the solution is heated to 100 0 C and the recycling pump is run for 120 minutes.
• a 6% (weight/volume) solution of sulphuric acid is charged, the mixture is heated to 60 0 C and is reacted with circulation of the solution for 60 minutes.
• the sulphuric acid solution is discharged and the mixture is washed with deionised water, for three cycles, at a temperature of 50 0 C in order to wash out the ammonium sulphate and hydrazine sulphate salts formed.
• the solution is discharged and washed with a cycle of water at 50 0 C.
• the washing water is discharged, the basket is ex- tracted from the reaction tank, it is then transferred to a centrifuge to eliminate the excess water.
• a finishing solution is fed, containing a cationic finish in such an amount that the concentration of this product in the final fibre is over 0.5% (weight/weight) .
• the fibre After centrifugation, the fibre is extracted and dried in a hot air oven.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Artificial Filaments (AREA)
• Chemical Or Physical Treatment Of Fibers (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Coloring (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (2)

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Family Applications (1)

Country Status (9)

Cited By (7)

Families Citing this family (3)

Citations (5)

• 2007
  • 2007-04-19 IT ITMI20070807 patent/ITMI20070807A1/it unknown
• 2008
  • 2008-04-09 WO PCT/EP2008/002875 patent/WO2008128660A1/en active Application Filing
  • 2008-04-09 EP EP08735177A patent/EP2137342A1/en not_active Withdrawn
  • 2008-04-09 JP JP2010503387A patent/JP2010525180A/ja active Pending
  • 2008-04-09 BR BRPI0810659-2A2A patent/BRPI0810659A2/pt not_active Application Discontinuation
  • 2008-04-09 CA CA002684074A patent/CA2684074A1/en not_active Abandoned
  • 2008-04-09 RU RU2009142611/05A patent/RU2009142611A/ru unknown
• 2009
  • 2009-10-19 TN TNP2009000433A patent/TN2009000433A1/fr unknown
  • 2009-11-17 MA MA32350A patent/MA31380B1/ar unknown

Patent Citations (5)

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