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
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/58—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products
  • D01F6/60—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyamides
  • D01F6/605—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyamides from aromatic polyamides

Definitions

• the application relates to a process for the wet spinning of preponderantly aromatic polyamides by spinning a spinning solution containing besides an aprotic solvent a dissolved metal halide into an aqueous salt-containing coagulation bath; the coagulation bath containing as salt the same metal halide as does the spinning solution.
• the process simplifies the manufacture of filaments made from hi gh-melting polyamides having a high dynamic efiiciency and partially a poor flammability, and it ensures an easy regeneration of the coagulation baths.
• the present invention relates to a process for the manufacture of filaments on the basis of high-melting polyamides.
• Polyamides having melting points above 300 C. partially possess very valuable properties apart from their good thermostability.
• those polymers can be processed from the melt only to a limited extent, especially because their melting and decomposition temperatures often are too near to each other.
• Shaped articles for example filaments, fibers, films, sheets, coatings and yarns, can therefore be manufactured only from the solution in most cases.
• the general rule for polyamides is the following: the higher the melting point, the lesser the solubility, since hydrogen bonds and cristallinity act in the opposite direction on the melting point and the solubility. Therefore, dissolving high temperature resistant, i.e. high-melting polyamides requires the use of quite special solvents, described for example in German Auslegeschriit No. 1,107,399.
• a process for the dissolution of nitrogen containing linear polycoudensation products in which at least 50% of the recurring units in the chain molecule of the polymer consist of the grouping is claimed, wherein substantially nonaqueous, acid-tree, organic solvents, so-called aprotic solvents, which can dissolve at least 0.5% by weight of the polycondensation product at room temperature, are used in combination with a salt splitting ofi chlorine or bromine ions, which salt is soluble in these solvents.
• Aprotic organic solvents are for example dimethylforrnamide, dimethylacetamide, N-methyl-Z-pyrrolidone or dimethylsulfoxide.
• aprotic organic solvents see for example the paper of A. I. Parker in Advances in Organic Chemistry, vol. 5 (1965), p. 1-46.
• 1,243,820 describes a process for the manufacture of filaments by wet spinning of a solution of a linear polyamide the amide bridges of which directly link purely aromatic groups into a hot aqueous coagulation bath containing at least 40% of calcium thiocyanate; the spinning solution in this case consists of a solution of the aforementioned linear polyamide in a. salt solution according to German Auslegeschrift No. 1,107,399.
• the spinning solution in this case consists of a solution of the aforementioned linear polyamide in a. salt solution according to German Auslegeschrift No. 1,107,399.
• Subject of the present invention is now a process for the wet spinning of polyamides in which at least of the amide groups are directly linked by purely aromatic groups from an aprotic solvent containing a dissolved colorless metal halide as spinning solution into an aqueous salt-containing coagulation bath, wherein this aqueous salt-containing coagulation bath contains the same metal halide as does the spinning solution.
• polyamides in which at least 80% of the amide groups are directly linked by purely aromatic groups which polyamides are to be spun according to the process of the invention, are for example described in US. Pat. No. 3,063,966.
• amide groups must not be directly linked by purely aromatic groups, but up to a maximum of 20% of the amide groups may be linked by non-aromatic groups (aliphatic, cyclo-aliphatic, araliphatic groups as known from the normal polyamides, for example from nylon-66).
• the melting points of these polyamides generally are above 300 C. or at least not much below 300 C., and the decomposition point in most cases is near the melting point.
• the polyamide to be spun is dissolved in a spinning solution of an aprotic solvent containing a dissolved colorless metal halide.
• colorless metal halides some chlorides and bromides of the elements of the 1st, 2d and 3rd main group and of the 2d subgroup of the periodic system of the elements are suitable; however, the chlorides of lithium, magnesium, calcium, zinc and aluminum are preferred, optionally also lithium bromide.
• pp. 146 may be used; preferable in this case are the lower aliphatic alkylamides, especially dimethylforamide and dimethylacetamide, furthermore N- methyl-pyrrolidone, tetramethylene-sulfone and dimethylsulfoxide.
• the viscosity of the spinning solution which should contain no more than by weight of metal halide, is adjusted to a falling ball time of from 50 to 1,500 seconds, preferably of from 100 to 600 seconds, determined according to the DIN 5401 method.
• a falling ball time of from 50 to 1,500 seconds preferably of from 100 to 600 seconds
• the above mentioned falling ball time of from 50 to 1,500, preferably of from 100 to 600 seconds, is attained at a polyamide concentration of from about to 25% by weight.
• the polyamides can be prepared in such a way as to obtain solutions ready to be spun containing the dissolved polyamide in desired concentrations in a mixture of an aprotic solvent and a metal halide, for example in dimethylacetamide/calcium chloride, the isolation and work-up of the polyamide before the spinning process in many cases is no more required.
• the spinning solution is pressed into the coagulation bath at room temperature.
• the filament may pass through the coagulation bath either in vertical or in horizontal direction.
• the coagulation bath is an aqueous solution of the same metal salt which is also present in the spinning solution.
• the salt concentration in the coagulation bath is from 15 to 60% by weight, preferably from about 25 to 50% by weight.
• a small amount of the organic aprotic solvent entering the coagulation bath from the spinning solution does not cause any disturbance of the spinning process.
• a content of from about 5 to 15% by weight of the organic aprotic solvent in the coagulation bath may even have a favourable influence on the quality of the filament.
• the temperature of the coagulation bath should be from about 50 to 150 C., preferably from about 70 to 110 C. The optimum coagulation bath condition necessary for the spinning process can rapidly be determined in a simple test.
• the coagulation filament strand generally is drawn off the coagulation bath by means of trio rollers running at constant speed, then washed and freed from salt in a suitable bath, advantageously in hot water, and drawn, pre-dried, and set with crystallisation at temperatures of from about 250 to 350 C.
• the essential point of the process of the invention i.e. the spinning solution as well as the coagulation bath containing the same metal salt though in different concentration, is at the same time its decisive advantage.
• the spinning solution as well as the coagulation bath containing the same metal salt though in different concentration
• an easy and trouble-free work-up of the coagulation bath is always possible.
• transparent filaments are obtained which, after a corresponding drawing and setting, possess excellent mechanical properties, so that they may be used in fields requiring a high dynamic efficiency, for example in tirecord or in threads for high-speed sewing machines.
• many of the polyamides spun according to the process of the invention are distinguished by their poor flammability.
• EXAMPLE 1 parts of a polycondensation product of m-phenylenediamine and isophthalic acid chloride having a relative viscosity of 2.64 (m 1.94) are dissolved in 680 parts of dimethylacetamide containing 2.17% of CaCl and 0.1% of H 0.
• the filtered and degassed solution has a viscosity of 168 falling ball seconds.
• the spinning solution is spun through a gold/platinum nozzle (alloy 70/30) having 140 holes of a diameter of 0.07 mm. into an aqueous coagulation bath containing 53% of calcium chloride.
• the portion of the coagulation bath through which the filament has to pass has a length of 30 cm.
• the spinning solution under a nitrogen pressure of 1 atm.
• the coagulated filament strand is drawn oil the coagulation bath at a speed of 5 m./min. by means of trio rollers, subsequently washed in a bath having a length of 150 cm. and containing water heated at 85 C., and simultaneously drawn by means of a further trio roller running at a speed of 18 m./min.
• a subsequent washing bath having a length of cm. and a temperature of 80 C., the filament is freed from the remaining solvent and salt.
• the filament strand then passes through a heating channel having a length of cm. and is predried by means of hot air of 250 C.
• the transparent filament so obtained has a titer of 0.6 d. tex, a tensile strength of 5.2 g./d. tex at 21% of elongation at break; the yield stress is 2.3 g./d. tex and the initial module 102 g./d. tex.
• EXAMPLE 2 A spinning solution made from parts of a condensation product of m-phenylene-diamine and isophthalic acid chloride having a relative viscosity of 2.64 1.94), dissolved in 850 parts of a mixture of 95 parts of dimethylformamide and 5 parts of lithium chloride, is spun under a nitrogen pressure of 1.6 atm. through a gold/platinum nozzle having 140 holes of a diameter of 0.08 mm. into a coagulation bath of 79 C. containing 31 parts of lithium chloride, 10 parts of dimethylformamide and 49 parts of water according to the conditions given in Example 1.
• the viscosity of the spinning solution is 176 falling ball seconds.
• the individual titer of the filament Wound up on a bobbin is 1.5 d. tex; its tensile strength is 3.0 g./d. tex at an elongation at break of 30%.
• EXAMPLE 3 l The spinning solution used in Example 1 is spun through a gold/platinum nozzle having 140 holes of a diameter of 0.07 mm. into the following coagulation baths:
• Tempera- Immer- Coagtflation e sion length, medium Percent 0. cm.
• EXAMPLE 4 A solution is prepared from 160 parts of a polycondensation product of m-phenylene-diamine and isophthalic acid chloride having a relative viscosity of 1.97 (711 1.33) in 640 parts of dimethylacetamide containing 2.0% of calcium chloride and 0.4% of water by introducing the polycondensate into the solvent mixture cooled to 2-5 C. and dispersing it thoroughly. Subsequently, the mixture is heated, while stirring, to 60 C. and maintained at this temperature for 30 minutes. After the mixture has been allowed to cool to room temperature, pressure filtration is carried out. The viscosity of the degassed solution of 130 falling ball seconds.
• the spinning solution is spun through a nozzle having 140 holes of diameter of 0.07 mm. into a coagulation bath containing parts of calcium chloride, 10 parts of dimethylacetarnide and 50 parts of water.
• the temperature of the coagulation bath is 78 0., its length is 10 cm.
• the filament strand is drawn oi? the coagulation bath at a speed of 20 m./min. by means of trio rollers and wound up on a perforated bobbin at a speed of 60 m./min.
• By washing the bobbin in a suitable vessel adhering components of the coagulation bath and the solvent are eliminated from the filament.
• the washed filament is then drawn for a further 100% by means of a contact heater of 330 C.
• a transparent, colorless filament having good physical properties is obtained: titer 2.5 d. tex; tensile strength 4.6 g./d. tex, elongation 19%.
• EXAMPLE 5 48 parts of a polycondensation product made from mphenylene-diamine and isophthalic acid chloride having a relative viscosity of 2.69 1.97) are dissolved in 252 parts of dimethylacetamide containing 2.36% of zinc chloride and 0.14% of water. The viscosity of the spinning solution is 101 falling ball seconds. The spinning solution is spun through a gold/platinum nozzle having 100 holes of a diameter of 0.15 mm. into an aqueous coagulation bath containing 40% of zinc chloride and 10% of dimethylacetamide. The portion of the coagulation bath through which the filament has to pass has a length of 60 cm., the temperature of the bath is 85 C.
• the filament strand is drawn ofi the coagulation bath at a speed of 10 HL/mifl.
• the after-treatment of the coagulated spun filament i.e. washing, drawing and setting, is carried out in analogy to the method described in Examples 1 and 2.
• EXAMPLE 6 For the preparation of a spinning solution, 48 parts of the polycondensate described in Example 5 are used.
• the solvent consists of 252 parts of dimethylacetamide containing 1.2% of magnesium chloride and 1.39% of water.
• the viscosity of the spinning solution is 198 falling balls seconds.
• the solution is spun through a nozzle having 100 holes of a diameter of 0.1 mm. into a coagulation bath containing 16% of magnesium chloride, 10% of dimethylacetamide and 74% of water.
• the portion of the coagulation bath through which the filament has to pass has a length of 60 cm., the coagulation bath has a temperature of 87 C.
• the coagulated spun filament is drawn oil the bath at a speed of 10 m./min. drawn 2.5 fold its original length, washed, dried, set under tension at 320 C. and finally wound up on a bobbin.
• EXAMPLE 7 A spinning solution of 48 parts of the polycondensate cited in Example 5 is prepared. As solvent, 252 parts of dimethylacetamide containing 3.26% of aluminium chloride and 0.03% of water are used. The 16% spinning solution is spun through a nozzle having 100 holes of a diameter of 0.15 mm., into a coagulation bath containing 30% of aluminium chloride, 9% of dimethylacetamide and 61% of water. The portion of the coagulation bath through which the filament has to pass has a length of 58 cm., the temperature of the bath is 90 C. The coagulated filament strand is drawn oif at a speed of 12 m./min. and washed. The filament washed free from salt is aftertreated in usual manner.
• EXAMPLE 8 22.5 parts of a polycondensation product of 4,4'-diamino-diphenyl ether and isophthalic acid chloride having a relative viscosity of 5.5 11mb 3.4) are dissolved in 106.25 parts of dimethylacetamide containing 1.87% of calcium chloride and 0.9% of Water. The spinning solution is spun in analogy to the method described in Example 1 in order to yield a filament.
• EXAMPLE 9 A polycondensation solution prepared according to known methods from m-phenylene-diamine and isophthalic acid chloride dissolved in dimethylacetamide is directly spun.
• the reaction solution contains 20% of polycondensate having a relative viscosity of 3.7 2.6) and 0.75% of calcium chloride.
• the falling ball viscosity of the solution is 1,400 seconds.
• the solution is spun through a nozzle having holes of a diameter of 0.15 mm. into a coagulation bath containing 40% of calcium chloride, 50% of water and 10% of dimethylacetamide.
• the portion of the coagulation bath through which the filament has to pass has a length of 58 cm., the temperature of the bath is 87 C.
• the coagulated filament strand is drawn oi the bath at a speed of 10 m./Inin.
• the filament washed in hot water having a temperature of 80 C. is drawn 3.5 fold its original length, dried, set with slight afterstretching at 325 C. by means of a contact heater, and wound up on a bobbin.
• a filament having good technological properties is obtained.
• EXAMPLE 10 For the preparation of a spinning solution, 48 parts of a polycondensation product of m-phenylene-diamine and isophthalic acid chloride having a relative viscosity of 2.63 (m 1.93) are dissolved in 252 parts of dimethylacetamide containing 5% of lithium bromide and 0.12% of water. At about 5 C., the polycondensate is introduced into the solvent mixture within 10 minutes and well dispersed. Subsequently, the mixture is heated to 60 C., While stirring, and maintained at this temperature for 30 minutes. After the mixture has been allowed to cool to room temperature, pressure filtration is carried out. The viscosity of the solution free from gas bubbles is 118 falling ball seconds.
• the spinning solution is then spun under a nitrogen pressure of 08 atm. from a boiler via a spinning pipe through a nozzle having 100 holes of a diameter of 0.1 mm. into a coagulation bath containing 40 parts of lithium bromide and 60 parts of water.
• the temperature of the coagulation bath is 70 C.
• the bath has a length of 60 cm.
• the filament strand is drawn off the coagulation bath at a speed of 20 m./min. by means of trio rollers. It is washed in a subsequent bath having a length of 120 cm. and containing hot water of 80 C., and simultaneously it is drawn by means of a further trio roller running at a 5 speed of 46 m./min.
• the filament is freed from traces of solvent and salt.
• the filament strand is then dried with tension, after-drawn over a contact heater having a temperature of 320 C., and set.
• the final winding-up on a bobbin is carried out at a speed of 60 m./ min.
• the filament obtained is transparent and has a tensile strength of 3.2 g./d. tex at an elongation of 25%.
• aprotic solvent being dimethylformamide, dimethylacetamide, N-methylpyrrolidone, tetramethylenesulfone or dimethylsulfoxide, containing a dissolved colorless metal halide of the elements of the first, second, third main group and of the second subgroup of the periodic system of elements as spinning solution into an aqueous salt-containing coagulation bath
• the improvement which comprises using as salt for the coagulation bath the same metal halide as for the spinning solution and wherein the salt concentration of the spinning solution does not exceed 10% by weight, and the salt concentration of the coagulation bath is from 15 to 60% by weight.
• polyamides to be spun contain isophathalic acid as acid component and at least one diamine selected from the group of m-phenylene-diamine, 4,4-diamino-diphenyl-methane and 4,4-diamino-diphenyl ether as diamine component.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Artificial Filaments (AREA)

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Publications (1)

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Cited By (7)

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• 1970
  • 1970-07-28 DE DE19702037254 patent/DE2037254A1/de active Pending
• 1971
  • 1971-07-23 NL NL7110184A patent/NL7110184A/xx unknown
  • 1971-07-26 US US00164857A patent/US3751546A/en not_active Expired - Lifetime
  • 1971-07-27 FR FR7127464A patent/FR2103737A5/fr not_active Expired
  • 1971-07-27 BE BE770553A patent/BE770553A/xx unknown
  • 1971-07-28 GB GB3550471A patent/GB1309037A/en not_active Expired

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