CA2684074A1 - Process for the production of fireproof polyacrylate fibre with a low emission of toxic fumes, uniformly dyed, and acrylic fibres thus obtained - Google Patents
Process for the production of fireproof polyacrylate fibre with a low emission of toxic fumes, uniformly dyed, and acrylic fibres thus obtained Download PDFInfo
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- CA2684074A1 CA2684074A1 CA002684074A CA2684074A CA2684074A1 CA 2684074 A1 CA2684074 A1 CA 2684074A1 CA 002684074 A CA002684074 A CA 002684074A CA 2684074 A CA2684074 A CA 2684074A CA 2684074 A1 CA2684074 A1 CA 2684074A1
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- 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
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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)
Abstract
Process for the production of fireproof polyacrylate fibre with a low emission of toxic fumes, uniformly dyed, which includes dissolving a copolymer of acrylonitrile in a solvent, containing an organic pigment, treating the solution to produce a pigmented acrylic fibre and subjecting the pigmented fibre to crosslinking, hydrolysis, acidification and neutralization treatment.
Description
PROCESS FOR THE PRODUCTION OF FIREPROOF POLYACRYLATE FI-BRE WITH A LOW EMISS-ION OF TOXIC FUMES, UNIFORMLY DYED, AND ACRYLIC FIBRES THUS OBTAINED
The present invention relates to a process for the production of fireproof polyacrylate fibre with a low emission of toxic fumes, uniformly dyed.
More specifically, 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.
Commercial acrylic fibre from a copolymer are used in traditional textile fields such as clothing, home fur-nishing, flooring, etc.. or in the field of outdoor awn-ings. The acrylic fibre from a homopolymer, less dif-fused, is used for reinforcing concrete, for the filtra-tion of fumes, etc..
As is known, there are also various kinds of 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 oxi-dized 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.
Other types of post-treatment of acrylic fibres have been studied and used for imparting new and interesting properties to the fibre such as fire-resistance or the absorption of considerable quantities of water.
These latter types of treatment include the transfor-mation of the CN groups into amide and carboxyl groups through extremely drastic chemical reactions and under unusual conditions. These forms of treatment can create products with the desired characteristics without resort-ing to the production of polymers which are difficult to handle and expensive.
A sequence of treatment of acrylic fibres has been known for some time, for example, first with hydrazine, followed by an alkaline hydrolysis of the CN groups, a subsequent neutralization with strong acids and finally a treatment with zinc salts, calcium salts, copper salts, etc.. After these modifications, the final product is a fibre with a L.O.I. (Limiting Oxygen Index) value higher than 40%, which does not melt, and does not release fumes.
The properties shown by the fibre after this series of treatment are definitely of commercial interest, for example, for protective clothing, under extreme condi-tions of fire exposure, or for textile furnishings in en-vironments in which fire-resistance and the absence of toxic fumes is essential (aeroplanes, trains, passenger ships, etc..).
In spite of these positive qualities, however, 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 pro-duced, 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 pressing constancy of strong acidic groups, nor-mally of the sulphonic type, which must be guaranteed on the fibre if a uniform dye is to be obtained, without striping, is known, for example, to producers of tradi-tional acrylic fibres.
Most of the complaints a producer of acrylic fibre must face relate to the dyeing uniformity.
To guarantee this uniformity of behaviour in the dye-ing phase, 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.
In the sequence of chemical reactions which, starting from a commercial acrylic fibre lead to a polyacrylate fibre, all the CN groups are modified: first by reaction of an aliquot of these groups, ranging from 20 to 600, with hydrazine for an inter- or intra-molecular crosslinking, subsequently by alkaline hydrolysis of the CN residues to amidic and carboxyl groups.
The subsequent neutralization with a strong acid, sulphuric acid, for example, leads to quaternizing of both the azide and amide groups, making the fibre suit-able for being dyed with pre-metallized dyes 1:1.
The present invention relates to a process for the production of fireproof polyacrylate fibre with a low emission of toxic fumes, uniformly dyed.
More specifically, 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.
Commercial acrylic fibre from a copolymer are used in traditional textile fields such as clothing, home fur-nishing, flooring, etc.. or in the field of outdoor awn-ings. The acrylic fibre from a homopolymer, less dif-fused, is used for reinforcing concrete, for the filtra-tion of fumes, etc..
As is known, there are also various kinds of 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 oxi-dized 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.
Other types of post-treatment of acrylic fibres have been studied and used for imparting new and interesting properties to the fibre such as fire-resistance or the absorption of considerable quantities of water.
These latter types of treatment include the transfor-mation of the CN groups into amide and carboxyl groups through extremely drastic chemical reactions and under unusual conditions. These forms of treatment can create products with the desired characteristics without resort-ing to the production of polymers which are difficult to handle and expensive.
A sequence of treatment of acrylic fibres has been known for some time, for example, first with hydrazine, followed by an alkaline hydrolysis of the CN groups, a subsequent neutralization with strong acids and finally a treatment with zinc salts, calcium salts, copper salts, etc.. After these modifications, the final product is a fibre with a L.O.I. (Limiting Oxygen Index) value higher than 40%, which does not melt, and does not release fumes.
The properties shown by the fibre after this series of treatment are definitely of commercial interest, for example, for protective clothing, under extreme condi-tions of fire exposure, or for textile furnishings in en-vironments in which fire-resistance and the absence of toxic fumes is essential (aeroplanes, trains, passenger ships, etc..).
In spite of these positive qualities, however, 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 pro-duced, 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 pressing constancy of strong acidic groups, nor-mally of the sulphonic type, which must be guaranteed on the fibre if a uniform dye is to be obtained, without striping, is known, for example, to producers of tradi-tional acrylic fibres.
Most of the complaints a producer of acrylic fibre must face relate to the dyeing uniformity.
To guarantee this uniformity of behaviour in the dye-ing phase, 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.
In the sequence of chemical reactions which, starting from a commercial acrylic fibre lead to a polyacrylate fibre, all the CN groups are modified: first by reaction of an aliquot of these groups, ranging from 20 to 600, with hydrazine for an inter- or intra-molecular crosslinking, subsequently by alkaline hydrolysis of the CN residues to amidic and carboxyl groups.
The subsequent neutralization with a strong acid, sulphuric acid, for example, leads to quaternizing of both the azide and amide groups, making the fibre suit-able for being dyed with pre-metallized dyes 1:1.
In reality, the chemical treatment is carried out batchwise, on traditional dyeing equipment, by position-ing 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, salifi-cation 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 per-meability of the fibre inside the basket, with a conse-quent non-homogeneous distribution of the modified CN
groups.
Another element which disturbs the homogeneity arises during the alkaline hydrolysis phase. In this phase, the formation of carboxyl groups leads to an enormous swell-ing of the fibre which becomes like a gelatine, analo-gously 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 gelatinous mass makes the circulation of the re-action liquid difficult, and this exalts the irregular chemical composition of the fibre even more. During this phase, in fact, the CN groups which have not reacted with hydrazine pass by alkaline hydrolysis first to amide and subsequently to carboxyl.
The subsequent phase consists of an acidification re-action with sulphuric acid, for example, of the carboxyl groups. The fibre, through this operation, loses its ge-latinous appearance and returns to a normal fibre, not swollen by water.
Another function of the acid is to quaternize the am-ide and azide groups responsible for the dyeing proper-ties of the fibre. Some of the carboxyl groups are subse-quently partly salified with metal ions, such as zinc, for example.
From the above, it can be understood that it is dif-ficult to guarantee a dyeing uniformity of the polyacry-late fibre.
It is obviously not possible to use, as precursor, an acrylic fibre dyed by means of traditional basic dyes, as these are not capable of resisting the series of chemical treatment envisaged.
The Applicant has now found that it is possible to overcome all the drawbacks of the known art by using an acrylic fibre already dyed in mass with selected organic pigments, capable of remaining unaltered with the chemi-cal treatment envisaged for modifying the chemical compo-sition of the fibre into crosslinked polyacrylate.
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 per-meability of the fibre inside the basket, with a conse-quent non-homogeneous distribution of the modified CN
groups.
Another element which disturbs the homogeneity arises during the alkaline hydrolysis phase. In this phase, the formation of carboxyl groups leads to an enormous swell-ing of the fibre which becomes like a gelatine, analo-gously 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 gelatinous mass makes the circulation of the re-action liquid difficult, and this exalts the irregular chemical composition of the fibre even more. During this phase, in fact, the CN groups which have not reacted with hydrazine pass by alkaline hydrolysis first to amide and subsequently to carboxyl.
The subsequent phase consists of an acidification re-action with sulphuric acid, for example, of the carboxyl groups. The fibre, through this operation, loses its ge-latinous appearance and returns to a normal fibre, not swollen by water.
Another function of the acid is to quaternize the am-ide and azide groups responsible for the dyeing proper-ties of the fibre. Some of the carboxyl groups are subse-quently partly salified with metal ions, such as zinc, for example.
From the above, it can be understood that it is dif-ficult to guarantee a dyeing uniformity of the polyacry-late fibre.
It is obviously not possible to use, as precursor, an acrylic fibre dyed by means of traditional basic dyes, as these are not capable of resisting the series of chemical treatment envisaged.
The Applicant has now found that it is possible to overcome all the drawbacks of the known art by using an acrylic fibre already dyed in mass with selected organic pigments, capable of remaining unaltered with the chemi-cal treatment envisaged for modifying the chemical compo-sition of the fibre into crosslinked polyacrylate.
With the use of particular pigments, it is possible to obtain a polyacrylate fibre also with dark colours, which has not been possible so far, due to the low con-centration of dyeable sites on the polyacrylate fibre.
The use of 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.
The use of pigmented fibre as precursor of polyacry-late 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 polyacry-late 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-.
ple 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 35,000 to 65,000, for example of about 50,000 atomic units;
b. dispersing in the polymeric solution obtained, alone or in a combination, according to the final colour desired, organic pigments of the type: Orange 43 (perinone), Blue 60 (indantrone), Blue 15:1 Copper phthalocyanine), Yellow 24 (flavantrone), Yellow 109 (tetrachloroisoindolinone), Red 149 (perylene) Green 36 (phthalocyanine), Green 7 (phthalocyanine), Black 7 (carbon black), etc.. so as to have a total final concentration of the pigment ranging from 0.5 to 3.50 by weight.
c. treating the acrylic copolymer/pigment mix to produce a pigmented acrylic fibre as staple or tow;
d. subjecting the pigmented acrylic fibre to a crosslinking step by means of an aqueous solution of hydrazine hydrate;
e. subjecting the crosslinked fibre to an alkaline hy-drolysis step;
f. subjecting the crosslinked/hydrolyzed fibre to treat-ment with a strong acid; and g. salifying the final fibre with an organic metal salt.
At the end of the process object of the present in-vention, a uniformly dyed polyacrylate fibre is obtained with a L.O.I. (Limiting Oxygen Index) higher than 37%
According to the present invention, 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.
In particular, a solution with a concentration rang-ing from 23 to 28o 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 cm3/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 wa-ter/dimethyl acetamide solution in a 1:1 ratio at a tem-perature of 500C.
The cord of coagulated tows is extracted from the co-agulation 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.
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 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 auto-clave with saturated vapour, at a relative pressure of 1.7 bar. The fibre undergoes a shrinkage of 30o with re-spect 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 characteris-tics:
titre 2.0 dtex toughness 32.5 CN/Tex Ultimate elongation 3506 With respect to the colours which can be used for the acrylic fibre dyed with solid pigments, examples of prod-ucts can be those described in the colour chart of Leac-ril OD of Montefibre, among which:
Black N034 - N039 Blue B069 - B109 - B112 - B115 Red R035 - R042 - R089 Green V005 - V006 - V034 Brown M113 - M074 - M560 Yellow G028 - G043 - G033 Once the pigmented acrylic fibre has been obtained, the same can be treated to make it fire-proof. This step of the process, object of the present invention, starts with step (d), according to which 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 1500C, preferably from 80 to 120 C.
After a period of time sufficiently long to have a crosslinking, inter- and/or intra-molecular, higher than 20%, for example from 25 to 60%, with respect to the to-tal number of CN groups contained in the polymeric chain of the polyacrylonitrile homopolymer, 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 80, preferably from 3 to 6% (weight/volume). The treatment with the al-kaline solution takes place at atmospheric pressure, or slightly higher, and at a temperature ranging from 70 to 120 C, preferably from 80 to 110 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 ex-ample 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 fi-bres 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 C, preferably from 50 to 70 C.
Finally, 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. 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 C, preferably from 90 to 110 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 use of 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.
The use of pigmented fibre as precursor of polyacry-late 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 polyacry-late 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-.
ple 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 35,000 to 65,000, for example of about 50,000 atomic units;
b. dispersing in the polymeric solution obtained, alone or in a combination, according to the final colour desired, organic pigments of the type: Orange 43 (perinone), Blue 60 (indantrone), Blue 15:1 Copper phthalocyanine), Yellow 24 (flavantrone), Yellow 109 (tetrachloroisoindolinone), Red 149 (perylene) Green 36 (phthalocyanine), Green 7 (phthalocyanine), Black 7 (carbon black), etc.. so as to have a total final concentration of the pigment ranging from 0.5 to 3.50 by weight.
c. treating the acrylic copolymer/pigment mix to produce a pigmented acrylic fibre as staple or tow;
d. subjecting the pigmented acrylic fibre to a crosslinking step by means of an aqueous solution of hydrazine hydrate;
e. subjecting the crosslinked fibre to an alkaline hy-drolysis step;
f. subjecting the crosslinked/hydrolyzed fibre to treat-ment with a strong acid; and g. salifying the final fibre with an organic metal salt.
At the end of the process object of the present in-vention, a uniformly dyed polyacrylate fibre is obtained with a L.O.I. (Limiting Oxygen Index) higher than 37%
According to the present invention, 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.
In particular, a solution with a concentration rang-ing from 23 to 28o 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 cm3/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 wa-ter/dimethyl acetamide solution in a 1:1 ratio at a tem-perature of 500C.
The cord of coagulated tows is extracted from the co-agulation 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.
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 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 auto-clave with saturated vapour, at a relative pressure of 1.7 bar. The fibre undergoes a shrinkage of 30o with re-spect 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 characteris-tics:
titre 2.0 dtex toughness 32.5 CN/Tex Ultimate elongation 3506 With respect to the colours which can be used for the acrylic fibre dyed with solid pigments, examples of prod-ucts can be those described in the colour chart of Leac-ril OD of Montefibre, among which:
Black N034 - N039 Blue B069 - B109 - B112 - B115 Red R035 - R042 - R089 Green V005 - V006 - V034 Brown M113 - M074 - M560 Yellow G028 - G043 - G033 Once the pigmented acrylic fibre has been obtained, the same can be treated to make it fire-proof. This step of the process, object of the present invention, starts with step (d), according to which 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 1500C, preferably from 80 to 120 C.
After a period of time sufficiently long to have a crosslinking, inter- and/or intra-molecular, higher than 20%, for example from 25 to 60%, with respect to the to-tal number of CN groups contained in the polymeric chain of the polyacrylonitrile homopolymer, 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 80, preferably from 3 to 6% (weight/volume). The treatment with the al-kaline solution takes place at atmospheric pressure, or slightly higher, and at a temperature ranging from 70 to 120 C, preferably from 80 to 110 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 ex-ample 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 fi-bres 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 C, preferably from 50 to 70 C.
Finally, 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. 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 C, preferably from 90 to 110 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.
At the end of the fire-proofing treatment, 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 in-vention and for its embodiment.
EXAMPLE
The tow of pigmented acrylic fibre, which can be transformed into a staple on a cutting machine, is pro-duced 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.
For illustrative purposes, the above-mentioned pig-ments are dispersed in the solution of the acryloni-trile/vinyl acetate copolymer at 25.5o 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 conse-quence of the crosslinking - hydrolysis - salification treatment.
Lots of fibre were produced, for example, in differ-ent colours, mostly dark, to cover the pink-coloured base deriving from the chemical treatment, and using a pre-dominant pigment in the concentrations shown in table I:
Pigment Pigment concentra- Fibre colour (Colour Index) tion on the fibre (%) Blue 15:1 1.78 Turquoise blue Blue 60 1.42 Sea blue Yellow 24 0.92 yellow Red 149 1.39 bright red Orange 43 1.5 orange Green 7 2.3 forest green Black 7 2.3 dark black 300 kg of a tow of pigmented fibre, with a filament titre of 2.0 dtex and a tow titre of 100 ktex, are charged into a 1,000 litre punched basket, with contempo-raneous wetting and pressing so as to obtain a packing density of the fibre of 0.30 kg/l.
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 150 (weight/volume).
The solution is brought to 105 C and the circulation pump is kept in operation for 5 hours.
An illustrative and non-limiting example is provided hereunder for a better understanding of the present in-vention and for its embodiment.
EXAMPLE
The tow of pigmented acrylic fibre, which can be transformed into a staple on a cutting machine, is pro-duced 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.
For illustrative purposes, the above-mentioned pig-ments are dispersed in the solution of the acryloni-trile/vinyl acetate copolymer at 25.5o 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 conse-quence of the crosslinking - hydrolysis - salification treatment.
Lots of fibre were produced, for example, in differ-ent colours, mostly dark, to cover the pink-coloured base deriving from the chemical treatment, and using a pre-dominant pigment in the concentrations shown in table I:
Pigment Pigment concentra- Fibre colour (Colour Index) tion on the fibre (%) Blue 15:1 1.78 Turquoise blue Blue 60 1.42 Sea blue Yellow 24 0.92 yellow Red 149 1.39 bright red Orange 43 1.5 orange Green 7 2.3 forest green Black 7 2.3 dark black 300 kg of a tow of pigmented fibre, with a filament titre of 2.0 dtex and a tow titre of 100 ktex, are charged into a 1,000 litre punched basket, with contempo-raneous wetting and pressing so as to obtain a packing density of the fibre of 0.30 kg/l.
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 150 (weight/volume).
The solution is brought to 105 C and the circulation pump is kept in operation for 5 hours.
At the end of the reaction, the reacted hydrazine hy-drate 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 C.
A soda solution is then charged in such a quantity as to have a concentration of 5% (weight/volume) in the liq-uid phase. The solution is heated to 100 C and the recy-cling pump is run for 120 minutes.
At the end of the reaction, a 60 (weight/volume) so-lution of sulphuric acid is charged, the mixture is heated to 60 C and is reacted with circulation of the so-lution for 60 minutes.
Finally, the sulphuric acid solution is discharged and the mixture is washed with deionised water, for three cycles, at a temperature of 50 C in order to wash out the ammonium sulphate and hydrazine sulphate salts formed.
127 Kg of dihydrated zinc acetate are charged together with 16.8 litres of glacial acetic acid, the whole solu-tion is heated to 100 C and is kept under circulation for 60 minutes.
At the end of the reaction, the solution is dis-charged and washed with a cycle of water at 50 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.
After drainage of most of the liquid in excess, 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).
After centrifugation, the fibre is extracted and dried in a hot air oven.
The characteristics of the final fibre are indicated in the following table II
Table II
Parameter Measuring unit Value Titre dtex 4.0 Toughness CN/tex 18.0 Ultimate elongation % 25.5 L.O.I. % 37.5
A soda solution is then charged in such a quantity as to have a concentration of 5% (weight/volume) in the liq-uid phase. The solution is heated to 100 C and the recy-cling pump is run for 120 minutes.
At the end of the reaction, a 60 (weight/volume) so-lution of sulphuric acid is charged, the mixture is heated to 60 C and is reacted with circulation of the so-lution for 60 minutes.
Finally, the sulphuric acid solution is discharged and the mixture is washed with deionised water, for three cycles, at a temperature of 50 C in order to wash out the ammonium sulphate and hydrazine sulphate salts formed.
127 Kg of dihydrated zinc acetate are charged together with 16.8 litres of glacial acetic acid, the whole solu-tion is heated to 100 C and is kept under circulation for 60 minutes.
At the end of the reaction, the solution is dis-charged and washed with a cycle of water at 50 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.
After drainage of most of the liquid in excess, 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).
After centrifugation, the fibre is extracted and dried in a hot air oven.
The characteristics of the final fibre are indicated in the following table II
Table II
Parameter Measuring unit Value Titre dtex 4.0 Toughness CN/tex 18.0 Ultimate elongation % 25.5 L.O.I. % 37.5
Claims (16)
1. 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 in a sol-vent;
b. dispersing at least one organic pigment in the polymeric solution obtained;
c. treating the acrylic copolymer/pigment mix to produce a pigmented acrylic fibre as a staple or tow;
d. subjecting the pigmented acrylic fibre to a crosslinking step by means of an aqueous solution of hydrazine hydrate;
e. subjecting the crosslinked fibre to an alkaline hydrolysis step;
f. subjecting the crosslinked/hydrolyzed fibre to treatment with a strong acid; and g. salifying the final fibre with an organic metal salt.
a. dissolving an acrylonitrile copolymer in a sol-vent;
b. dispersing at least one organic pigment in the polymeric solution obtained;
c. treating the acrylic copolymer/pigment mix to produce a pigmented acrylic fibre as a staple or tow;
d. subjecting the pigmented acrylic fibre to a crosslinking step by means of an aqueous solution of hydrazine hydrate;
e. subjecting the crosslinked fibre to an alkaline hydrolysis step;
f. subjecting the crosslinked/hydrolyzed fibre to treatment with a strong acid; and g. salifying the final fibre with an organic metal salt.
2. The process according to claim 1, wherein the solvent of step (a) is dimethyl acetamide.
3. The process according to claim 1 or 2, wherein the acrylonitrile copolymer is an acrylonitrile/vinyl acetate copolymer with a weight ratio between the mono-mers ranging from 90/10 to 99/1 and having a number aver-age molecular weight Mn ranging from 35,000 to 65,000.
4. The process according to any of the previous claims, wherein the concentration of the acrylonitrile copolymer in the solution ranges from 23 to 28% by weight.
5. The process according to any of the previous claims, wherein the organic pigment is selected from perinone, indantrone, Cu phthalocyanine, flavantrone, tetrachloroi-soindolinone, perylene, phthalocyanines, carbon black.
6. The process according to any of the previous claims, wherein the final total concentration of the organic pig-ment ranges from 0.5 to 3.5 by weight.
7. The process according to any of the previous claims, wherein the crosslinking step (d) is carried out with an aqueous solution of hydrazine hydrate at a concentration ranging from 5 to 25%.
8. The process according to any of the previous claims, wherein the crosslinking step (d) is carried out at a temperature ranging from 70 to 150°C.
9. The process according to any of the previous claims, wherein the alkaline hydrolysis step (e) is carried out with an alkaline aqueous solution at a concentration ranging from 1 to 8%.
10. The process according to any of the previous claims, wherein the alkaline hydrolysis step is carried out at a temperature ranging from 70 to 120°C.
11. The process according to any of the previous claims, wherein the acid neutralization step (f) is carried out by means of an inorganic acid, diluted in water, at con-centrations ranging from 2 to 10%.
12. The process according to any of the previous claims, wherein the acid neutralization step is carried out at a temperature ranging from 40 to 80°C.
13. The process according to any of the previous claims, wherein the salification step (g) is carried out by means of an aqueous solution of a zinc organic salt having a concentration ranging from 1 to 8%.
14. The process according to any of the previous claims, wherein the salification step is carried out at a tem-perature ranging from 80 to 120°C.
15. A fire-proof polyacrylate fibre, with a low emission of fumes and uniformly dyed, which can be obtained with the process according to any of the previous claims.
16. Fabrics and non-woven fabrics prepared with at least the fibre of claim 15.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ITMI2007A000807 | 2007-04-19 | ||
| ITMI20070807 ITMI20070807A1 (en) | 2007-04-19 | 2007-04-19 | PROCEDURE FOR THE PRODUCTION OF FIREPROOF AND LOW EMISSION FIBER POLYAMILATE FIBERS UNIFORMLY TINTED AND ACRYLIC FIBERS SO OBTAINED |
| PCT/EP2008/002875 WO2008128660A1 (en) | 2007-04-19 | 2008-04-09 | Process for the production of fireproof polyacrylate fibre with a low emission of toxic fumes, uniformly dyed, and acrylic fibres thus obtained |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2684074A1 true CA2684074A1 (en) | 2008-10-30 |
Family
ID=38476119
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002684074A Abandoned CA2684074A1 (en) | 2007-04-19 | 2008-04-09 | Process for the production of fireproof polyacrylate fibre with a low emission of toxic fumes, uniformly dyed, and acrylic fibres thus obtained |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP2137342A1 (en) |
| JP (1) | JP2010525180A (en) |
| BR (1) | BRPI0810659A2 (en) |
| CA (1) | CA2684074A1 (en) |
| IT (1) | ITMI20070807A1 (en) |
| MA (1) | MA31380B1 (en) |
| RU (1) | RU2009142611A (en) |
| TN (1) | TN2009000433A1 (en) |
| WO (1) | WO2008128660A1 (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101845748B (en) * | 2010-05-05 | 2012-03-28 | 山东理工大学 | Method for modifying flame retardance for acrylic fiber yarns |
| IT1402649B1 (en) * | 2010-08-02 | 2013-09-13 | Tecfiber Sarl | FIREPROOF FIBERS BASED ON POLIACRILATE MODIFIED BY THE APPLICATION OF NANOTECHNOLOGIES AND PROCEDURE FOR THEIR PRODUCTION |
| WO2013114159A1 (en) | 2012-02-01 | 2013-08-08 | Tecfiber Sarl | Polyacrylate-based flameproof fibres modified through the application of nanotechnologies and procedure for their production |
| JP5869719B1 (en) * | 2015-07-22 | 2016-02-24 | 東洋紡Ｓｔｃ株式会社 | Knitted fabric with uniform surface quality |
| WO2017139831A1 (en) | 2016-02-19 | 2017-08-24 | Metis Technologies Pty Ltd | Flame-retardant acrylonitrile polymer for fibre manufacture |
| CN107339429B (en) * | 2017-05-19 | 2019-01-04 | 江苏骆氏减震件有限公司 | A kind of wear resistant packing and preparation method thereof |
| US11946173B2 (en) | 2020-05-20 | 2024-04-02 | Glen Raven, Inc. | Yarns and fabrics including modacrylic fibers |
| WO2022235999A1 (en) * | 2021-05-07 | 2022-11-10 | Glen Raven, Inc. | High visibility yarns and fabrics and methods relating thereto |
| WO2023195951A1 (en) * | 2022-04-04 | 2023-10-12 | Aksa Akrilik Kimya Sanayii Anonim Sirketi | Improved polyacrylate fiber production process and their use |
| WO2023219590A1 (en) * | 2022-05-11 | 2023-11-16 | Aksa Akrilik Kimya Sanayii Anonim Sirketi | Fire proof and flame retardant polyacrylate fiber and production method thereof |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL277943A (en) * | 1961-05-02 | |||
| JPS503149A (en) * | 1973-05-14 | 1975-01-14 | ||
| WO2003010382A1 (en) * | 2001-07-25 | 2003-02-06 | Japan Exlan Company Limited | Fiber structure having high whiteness and high moisture-absorbing and releasing property, and method for production thereof |
| JP4674429B2 (en) * | 2001-09-18 | 2011-04-20 | 日本エクスラン工業株式会社 | Black high moisture absorbing / releasing fiber |
| FR2866904A1 (en) * | 2004-02-26 | 2005-09-02 | Marti Juan Batlle | PROCESS FOR PRODUCING RETICULATED POLYACRYLATE FIBERS |
-
2007
- 2007-04-19 IT ITMI20070807 patent/ITMI20070807A1/en unknown
-
2008
- 2008-04-09 WO PCT/EP2008/002875 patent/WO2008128660A1/en active Application Filing
- 2008-04-09 CA CA002684074A patent/CA2684074A1/en not_active Abandoned
- 2008-04-09 RU RU2009142611/05A patent/RU2009142611A/en unknown
- 2008-04-09 EP EP08735177A patent/EP2137342A1/en not_active Withdrawn
- 2008-04-09 JP JP2010503387A patent/JP2010525180A/en active Pending
- 2008-04-09 BR BRPI0810659-2A2A patent/BRPI0810659A2/en not_active Application Discontinuation
-
2009
- 2009-10-19 TN TNP2009000433A patent/TN2009000433A1/en unknown
- 2009-11-17 MA MA32350A patent/MA31380B1/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| ITMI20070807A1 (en) | 2008-10-20 |
| MA31380B1 (en) | 2010-05-03 |
| WO2008128660A8 (en) | 2009-01-15 |
| EP2137342A1 (en) | 2009-12-30 |
| JP2010525180A (en) | 2010-07-22 |
| WO2008128660A1 (en) | 2008-10-30 |
| BRPI0810659A2 (en) | 2014-11-04 |
| RU2009142611A (en) | 2011-05-27 |
| TN2009000433A1 (en) | 2011-03-31 |
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