CN116180261A

CN116180261A - High-strength yarn for polyamide 56 air bag yarn and preparation method thereof

Info

Publication number: CN116180261A
Application number: CN202111431468.2A
Authority: CN
Inventors: 孙朝续; 秦兵兵; 刘修才
Original assignee: Cathay R&D Center Co Ltd; CIBT America Inc
Current assignee: Cathay R&D Center Co Ltd; CIBT America Inc
Priority date: 2021-11-29
Filing date: 2021-11-29
Publication date: 2023-05-30

Abstract

The invention relates to the technical field of polyamide materials, and discloses a high-strength yarn for a polyamide 56 air bag yarn and a preparation method thereof, wherein the high-strength yarn for the high-capacity high-performance bio-based polyamide 56 air bag yarn is prepared by optimizing a melt direct spinning process, and the high-strength yarn for the high-strength yarn has the advantages of stable production, less broken filaments, less hairiness, high fiber yield and excellent heat resistance.

Description

High-strength yarn for polyamide 56 air bag yarn and preparation method thereof

Technical Field

The invention belongs to the technical field of polyamide materials, and particularly relates to a high-strength yarn for a polyamide 56 air bag yarn and a preparation method thereof.

Background

Melt spinning is one of the main forming methods of synthetic fibers, abbreviated as melt spinning. Melt spinning is a direct spinning method and a chip spinning method. Direct spinning is to directly send the polymerized polymer melt to spinning; the slice spinning is to send the polymer solution to spinning after the preparation process of casting belt, granulating, drying and the like.

The polyamide 6 has high monomer content (about 10 wt%) and the slice can be extracted to realize melt spinning, so that the industrialized melt direct spinning can not be realized at present. The problems of gel, difficult dyeing and the like are easy to generate in the spinning process of polyamide 66, the problems are more difficult in the melt direct spinning technology of civil yarns, and the melt conveying pipeline and the spinning box body need to be disassembled, calcined and cleaned regularly although the melt direct spinning is partially realized in the field of industrial yarns, so that the spinning cost is increased.

CN 105669969B discloses a nylon 6 polymerization method and a melt direct spinning method thereof, which comprises the steps of preparing a polyamide 6 prepolymer at low temperature, controlling the content of oligomer in the melt in advance, and then completing polymerization by a method of strengthening the kinetics of polycondensation reaction before a large amount of cyclic oligomer is generated, so as to obtain a nylon 6 polymer melt with a certain molecular weight, wherein the extractable content in the obtained product is less than or equal to 1.5wt% and the cyclic dimer content is less than or equal to 0.2wt%; then, after the strengthening of the polycondensation reaction kinetics is finished, the melt spinning is directly carried out, but no technical breakthrough and industrialization cases exist yet.

CN103668510 a discloses a device and method for producing fine denier or superfine denier nylon 66 filaments, the device comprises an evaporator, a preheater, a reactor, a flash evaporator and a finisher system, nylon 66 salt water solution is subjected to polycondensation reaction to obtain nylon 66 melt, and then the nylon 66 melt is directly spun to prepare fine denier or superfine denier nylon 66POY filaments, the spinning speed is 4200-4300m/min, the spinning speed is low, the yield is low, and the fiber strength is low.

The biobased polyamide 56 adopts biobased pentanediamine as a monomer raw material, and the carbon emission corresponding to the biobased polyamide 56 per unit weight is reduced by more than 50 percent compared with the carbon emission of nylon 66 and nylon 6 with the same weight. The application and popularization of the bio-based polyamide 56 have positive effects on improving the external import dependence of key materials in China, and have important significance on solving the dependence on fossil resources and the sustainable development of low-carbon emission reduction. The bio-based polyamide 56 material has excellent mechanical properties, moisture absorption quick-drying property, skin-friendly property, wear resistance, good softness, low-temperature dyeing property and the like, and has wide application prospect in the fields of civil filaments, short fibers, industrial filaments, continuous bulked filaments, monofilaments and the like at present. However, no related research and report on the high-strength yarn for preparing the high-capacity bio-based polyamide 56 air bag yarn by melt direct spinning industrialization exist at present.

Disclosure of Invention

In order to meet the requirements of melt direct spinning industrial production of the bio-based polyamide 56, the high-strength yarn for the bio-based polyamide 56 air bag yarn with high capacity and high performance is prepared and obtained by optimizing the melt direct spinning process, and the high-strength yarn for the bio-based polyamide 56 air bag yarn has the advantages of stable production, few broken filaments, few hairiness, high fiber yield and excellent heat resistance.

A first object of the present invention is to provide a high strength yarn for a polyamide 56 air bag yarn, wherein the fineness of the high strength yarn for a polyamide 56 air bag yarn is 200 to 800dtex, further 300 to 750dtex, and further 350 to 700dtex; and/or

The breaking strength of the high-strength yarn for the polyamide 56 air bag yarn is 7.0-10.0cN/dtex, further 7.5-9.0cN/dtex, and further 8.0-8.8cN/dtex; the Coefficient of Variation (CV)% of breaking strength is not more than 3.5%, and more preferably not more than 3.0%; and/or

The elongation at break of the high-strength yarn for the polyamide 56 air bag yarn is 15-25%, further 18-24%, and further 20-23%; the Coefficient of Variation (CV)% of elongation at break is not more than 4.5%, more preferably not more than 4%, still more preferably not more than 3.8%; and/or

After the polyamide 56 air bag yarn is subjected to dry heat treatment for 4 hours at 180 ℃, the heat-resistant breaking strength retention rate is more than or equal to 90%, further more is more than or equal to 91%, and still further is more than or equal to 92%; and/or

The initial modulus of the high-strength yarn for the polyamide 56 air bag yarn is more than or equal to 43cN/dtex, further more is more than or equal to 45cN/dtex, and still further is more than or equal to 50cN/dtex; and/or

The high strength yarn for polyamide 56 air bag yarn has a copper ion content of 50 to 120ppm, further 55 to 110ppm, still further 60 to 100ppm, for example, 50ppm, 60ppm, 70ppm, 80ppm, etc., or a range of any two point values, for example, 50 to 70ppm, 60 to 70ppm, 50 to 80ppm, 60 to 80ppm, etc.

In some embodiments, the polyamide 56 balloon yarn has a number of broken filaments of 3/1 spin sites 24h or less, preferably 2/1 spin sites 24h or less, more preferably 1/1 spin sites 24h or less.

In some embodiments, the polyamide 56 balloon yarns have a high strength yarn yield of 95% or more, preferably 96% or more, more preferably 98% or more.

In some embodiments, the polyamide 56 air bag yarn uses high strength yarn having a hairiness of 1/1 cake (10 kg package), preferably 0.5/1 cake, more preferably 0/1 cake.

The second object of the invention is to provide a method for preparing high-strength yarn for polyamide 56 air bag yarn, which at least comprises the following steps:

(1) The high-viscosity polyamide 56 melt is conveyed into a spinning box body through a melt booster pump and a melt conveying pipeline to be drawn, so as to form primary filaments;

(2) And cooling, oiling, pre-networking, multi-stage stretching, tension heat setting, two-stage relaxation heat setting, main networking and winding the primary yarn to obtain the high-strength yarn for the polyamide 56 air bag yarn.

In some specific embodiments, in step (1), the Gao Nianju amide 56 melt has a relative viscosity of from 3.0 to 4.0, preferably from 3.1 to 3.8, more preferably from 3.2 to 3.6.

In some embodiments, the Gao Nianju amide 56 melt has an amino content of 30 to 60mmol/kg, preferably 33 to 50mmol/kg, and more preferably 35 to 45mmol/kg.

In some embodiments, the Gao Nianju amide 56 melt has an equilibrium moisture content of 200 to 800ppm, preferably 300 to 700ppm, and more preferably 350 to 500ppm.

In some embodiments, the Gao Nianju amide 56 melt has a copper ion content of 50 to 120ppm, preferably 55 to 110ppm, and more preferably 60 to 100ppm.

In some embodiments, the oligomer content of the polyamide 56 melt is 1.1wt% or less, preferably 1.0wt% or less, more preferably 0.9wt% or less, and even more preferably 0.8wt% or less.

In some embodiments, the Gao Nianju amide 56 melt conduit transfer length from the melt booster pump to the spin beam is 10-50m, preferably 13-45m, more preferably 15-40m, and even more preferably 18-35m.

In some embodiments, the Gao Nianju amide 56 melt residence time from the melt booster pump to the spin beam is from 6 to 45 minutes, preferably from 8 to 40 minutes, more preferably from 10 to 35 minutes, and even more preferably from 12 to 30 minutes.

In some embodiments, the method of preparing the polyamide 56 melt comprises the steps of: the preparation of polyamide 56 salt solution from pentylene diamine, adipic acid and water, and then the preparation of polyamide 56 melt by prepolymerization, flash evaporation and polycondensation.

In some specific embodiments, the molar ratio of pentanediamine to adipic acid is (1-1.08): 1.

in some embodiments, the polyamide 56 salt solution has a concentration of 40 to 80 weight percent.

In some embodiments, the polyamide 56 salt solution has a pH of 6.0 to 9.5.

In some embodiments, the prepolymerization is carried out at a pressure of 0.8 to 2.6MPa, preferably 1.0 to 2.4MPa, more preferably 1.3 to 2.2MPa, still more preferably 1.5 to 2.0MPa; the temperature of the prepolymerization is 180-275 ℃, preferably 190-270 ℃, more preferably 210-265 ℃, still more preferably 225-260 ℃.

In some embodiments, the pressure of the polycondensation is- (0-0.08) MPa, preferably- (0.02-0.07) MPa, more preferably- (0.03-0.06) MPa, still more preferably- (0.04-0.05) MPa; the temperature of the polycondensation is 265 to 295 ℃, preferably 270 to 293 ℃, more preferably 275 to 290 ℃, still more preferably 278 to 288 ℃.

In the invention, a heat stabilizer is added in the polymerization process of the pentanediamine and the adipic acid, or the heat stabilizer is added in a heat-resistant masterbatch form through a masterbatch online adding device and a dynamic mixer device, and then melt direct spinning is carried out. In the invention, the master batch on-line adding device and the dynamic mixer device are arranged between the polyamide 56 melt polycondensation device and the melt booster pump.

In some specific embodiments, the heat stabilizer is selected from any one or more of copper acetate, potassium iodide, potassium bromide, copper chloride, cuprous iodide, cupric oxide and cuprous oxide, preferably copper acetate and potassium iodide or cuprous iodide and potassium iodide.

In some embodiments, the heat resistant masterbatch has a copper ion content of 1 to 10wt%, preferably 2 to 8wt%, more preferably 3 to 6wt%; the heat-resistant master batch is added in an amount of 0.05 to 2.0wt%, preferably 0.08 to 1.5wt%, more preferably 0.12 to 1.0wt% based on the total weight of the production raw materials.

In some embodiments, the drawing in step (1) is performed by spraying the Gao Nianju amide 56 melt through a spinneret of a spinning beam to form the as-spun filaments.

In some embodiments, the temperature of the spinning beam is 280-300 ℃, preferably 283-295 ℃, more preferably 285-293 ℃.

In some embodiments, the pressure of the spin pack assembly in the spin beam is greater than or equal to 10MPa, more preferably greater than or equal to 11MPa, and even more preferably greater than or equal to 12MPa.

In some embodiments, the filter screen in the spin pack assembly has a size of 100-600 mesh, further 200-550 mesh, and still further 300-500 mesh.

In some embodiments, the size of the metal sand in the spin pack assembly is 30-100 mesh, further 40-80 mesh, and still further 45-60 mesh.

In some embodiments, the spinneret has a spinneret draw ratio of 40 to 90, preferably 50 to 80.

In some embodiments, the spinneret has a hole count of 18 to 300f, preferably 24 to 210f, more preferably 36 to 192f, and even more preferably 48 to 136f.

In some specific embodiments, in step (2), the cooling is performed by using a side air blower or a circular air blower; the wind speed is preferably 0.4 to 0.9m/s, more preferably 0.5 to 0.8m/s; the wind temperature is preferably 16-25 ℃, more preferably 18-22 ℃; the humidity is preferably 50 to 90%, more preferably 60 to 85%.

In some specific embodiments, in step (2), the pre-network pressure is 1-2.5bar, preferably 1.5-2.0bar.

In some specific embodiments, in step (2), the multi-stage stretching process is performed using five pairs of hot rolls and more, preferably six pairs of hot rolls, and the stretching process is performed in five stages, where the stretching process is: the primary yarn after oiling is firstly fed into a first pair of hot rolls, first-stage pre-stretching is carried out between the first pair of hot rolls and a second pair of hot rolls, then second-stage main stretching is carried out between the second pair of hot rolls and a third pair of hot rolls, third-stage main stretching is carried out between the third pair of hot rolls and a fourth pair of hot rolls, tension heat setting is carried out, fourth-stage stretching is carried out between the fourth pair of hot rolls and a fifth pair of hot rolls, first relaxation heat setting is carried out, fifth-stage stretching is carried out between the fifth pair of hot rolls and a sixth pair of hot rolls, second relaxation heat setting is carried out, and finally winding forming is carried out by adopting a winding head.

In one embodiment, the first pair of heated rolls has a speed of 400-800m/min, preferably 450-750m/min, and a temperature of 20-70 ℃, preferably 30-60 ℃.

In one embodiment, the speed of the second pair of heated rolls is 450-950m/min, preferably 500-900m/min, and the temperature is 80-150 ℃, preferably 90-130 ℃.

In one embodiment, the speed of the third pair of heated rolls is 1500-2500m/min, preferably 1700-2300m/min, and the temperature is 130-210 ℃, preferably 150-200 ℃.

In one embodiment, the speed of the fourth pair of heated rolls is 2400-3500m/min, preferably 2500-3450m/min, and the temperature is 180-230 ℃, preferably 190-220 ℃.

In one embodiment, the speed of the fifth pair of heated rolls is 2350-3450m/min, preferably 2450-3400m/min, and the temperature is 160-220 ℃, preferably 170-200 ℃.

In one embodiment, the speed of the sixth pair of heated rolls is 2300-3400m/min, preferably 2400-3350m/min, and the temperature is 140-210 ℃, preferably 150-180 ℃.

In one embodiment, the total stretch factor of the stretch is 4.5 to 6.0, preferably 4.8 to 5.7.

In one embodiment, the speed retraction of the fourth and fifth pairs of heat rollers is 30-200m/min, preferably 50-150m/min.

In one embodiment, the fifth and sixth pairs of heated roll speed retractions are in the range of 30 to 200m/min, preferably 50 to 150m/min.

In one embodiment, the main network pressure is 2.5-4.5bar, preferably 3.0-3.5bar.

In one embodiment, the winding tension during the winding is 20 to 100cN, preferably 30 to 80cN, more preferably 40 to 70cN.

In one embodiment, the winding speed is 2200-3300m/min, preferably 2400-3250m/min, more preferably 2500-3200m/min; the winding overfeed ratio is 0.5-5%, preferably 1.0-4%, more preferably 1.3-3%.

In some embodiments, the retraction and winding process is provided with a humidifying device, wherein the humidifying temperature is 18-30 ℃, preferably 20-28 ℃, more preferably 22-26 ℃; the humidity is 60 to 95%, preferably 65 to 90%, more preferably 70 to 85%.

On the basis of conforming to the common knowledge in the field, the above preferred conditions can be arbitrarily combined to obtain the preferred examples of the invention. The reagents and materials used in the present invention are commercially available.

The invention has the positive progress effects that:

first, the invention can directly prepare the high-viscosity polyamide 56 melt for high-strength industrial yarn production by optimizing the polymerization process and formula adjustment, can save the procedures of polymerization and granulating, solid-phase polycondensation and humidity adjustment, and saves the production cost.

Secondly, by adopting the preparation method of the high-strength yarn for the polyamide 56 air bag yarn, parameters such as the conveying length of a melt pipeline, the residence time of the melt and the like are controlled by optimizing the melt direct spinning process, so that the high-strength yarn for the high-capacity polyamide 56 air bag yarn can be produced, the high-strength yarn for the polyamide 56 air bag yarn has the characteristics of heat resistance and less hairiness, and the gel content of a melt booster pump in a spinning box body can be effectively reduced.

Specifically, the annual output of the high-strength yarn for the melt direct spinning polyamide 56 air bag yarn is less than or equal to 5 ten thousand tons/line, preferably less than or equal to 4 ten thousand tons/line, more preferably less than or equal to 3 ten thousand tons/line, further preferably less than or equal to 2 ten thousand tons/line, the spinning position is less than or equal to 50 bits/line, preferably less than or equal to 40 bits/line, more preferably less than or equal to 30 bits/line, further preferably less than or equal to 25 bits/line, and the number of spinning heads is 2-12 heads/bit, preferably 4-8 heads/bit. The preparation method saves links of melt granulation, slice drying, screw melting and the like in the slice spinning process, and greatly reduces the production cost of the high-strength yarn for the polyamide 56 air bag yarn. The gel content can be controlled to be less than or equal to 1.0wt%/6 months, preferably less than or equal to 0.8wt%/6 months, more preferably less than or equal to 0.6wt%/6 months, and even more preferably less than or equal to 0.4wt%/6 months, so that the disassembly, calcination and cleaning times of a melt pipeline and a spinning box body are greatly reduced, and the production cost is reduced.

Thirdly, the invention can control parameters such as the conveying length of a melt pipeline, the residence time of the melt and the like by optimizing the melt direct spinning process, and can also ensure that the melt of the polyamide 56 is stable and the fluctuation of viscosity and amino is small.

Specifically, the absolute value of the change of the viscosity of the high-strength yarn for the polyamide 56 airbag yarn compared with the viscosity of the melt is controlled to be less than or equal to 0.1, preferably less than or equal to 0.08, more preferably less than or equal to 0.06, and even more preferably less than or equal to 0.05; the absolute value of the amino group change is controlled to be 3.0mmol/kg or less, preferably 2.5mmol/kg or less, more preferably 2.0mmol/kg or less, and still more preferably 1.5mmol/kg or less.

Fourth, the humidifying device is arranged in the retraction and winding process, the polyamide 56 air bag wire is retracted by absorbing water in the high-strength wire winding process, the internal stress generated by high-power drafting is fully released, the dimensional stability is good, and the breaking strength and the elongation fluctuation are small.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described in the following in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention. The experimental methods, in which specific conditions are not noted in the following examples, were selected according to conventional methods and conditions, or according to the commercial specifications.

The testing method comprises the following steps:

(1) Fineness: measured according to GB/T14343.

(2) Breaking strength, coefficient of variation of breaking strength (CV): measured according to GB/T14344-2008.

(3) Elongation at break, coefficient of variation of elongation at break (CV): measured according to GB/T14344-2008.

(4) Heat-resistant breaking strength retention rate: heat-resistant breaking strength retention= (breaking strength after heat treatment/breaking strength before heat treatment) ×100% and breaking strength was measured according to GB/T14344-2008, and the heat treatment equipment was an oven, a wire-wound frame.

(5) Initial modulus: measured according to GB/T14344-2008.

(6) Relative viscosity: concentrated sulfuric acid method by Ubbelohde viscometer: accurately weighing 0.5+/-0.0002 g after online taking a polyamide melt sample and drying, and adding 50mL of concentrated sulfuric acid (96 wt%) for dissolution; measurement and recording of the flow-through time t of concentrated sulfuric acid in a constant temperature water bath at 25 DEG C ₀ And polyamide sample solution flow-through time t. The viscosity number calculation formula: relative viscosity = t/t ₀ The method comprises the steps of carrying out a first treatment on the surface of the t-time of solution flow; t is t ₀ Solvent flow-through time.

(7) Amino-terminated: measured according to an automatic titration apparatus.

(8) Balancing the water content: the measurement was carried out by a Karl Fischer water titration apparatus.

(9) Copper ion content: and (5) measuring by an elemental analyzer.

(10) Oligomer content: in the water boiling method, the polyamide 56 melt is extracted in hot water with the temperature of more than or equal to 97 ℃, and the hot water extractables content of the dry slices is calculated by the poor quality of the dry slices before and after extraction.

(11) Number of filament breaks: and (5) manually counting.

(12) The preparation rate is as follows: yield = (mass of finished fiber prepared/mass of total polyamide melt input) ×100%.

(13) Gel content: randomly extracting melt samples in 6 melt conveying pipelines after 6 months of operation of a production line, measuring and taking an average value according to the following method, weighing, cooling and drying, taking the mass of the melt samples as A1, carrying out reflux extraction by using a Soxhlet extraction method, taking out samples, drying, weighing the mass of the samples in a filter paper bag as A2, and calculating the gel content according to the formula: gel content wt% = A2/A1 x 100%.

Example 1 high strength yarn for polyamide 56 balloon yarn of 315dtex/136f gauge

Preparation of highly viscous polyamide 56 melt

Preparing a polyamide 56 salt solution from pentylene diamine, adipic acid and water, and then carrying out prepolymerization, flash evaporation and polycondensation to obtain a high-viscosity polyamide 56 melt;

wherein the molar ratio of the pentanediamine to the adipic acid is 1.03:1; the concentration of the polyamide 56 salt solution is 60wt%; the pH value of the polyamide 56 salt solution is 7.6;

the pre-polymerization pressure is 1.73MPa, and the pre-polymerization temperature is 252 ℃;

the pressure of the polycondensation is-0.04 MPa, and the temperature of the polycondensation is 283 ℃;

adding a heat stabilizer in the polymerization process of the pentanediamine and the adipic acid, wherein the heat stabilizer is compounded by copper acetate and potassium iodide;

the Gao Nianju amide 56 melt has a copper ion content of 70ppm, a relative viscosity of 3.4, an oligomer content of 0.7wt%, an amino content of 40mmol/kg and a balance moisture content of 460ppm.

Preparation of high-strength yarn for polyamide 56 air bag yarn

(1) Drawing the obtained high-viscosity polyamide 56 melt into a spinning box body through a melt booster pump and a melt conveying pipeline to form primary filaments;

(2) Cooling, oiling, pre-networking, multi-stage stretching, tension heat setting, two-stage relaxation heat setting, main networking and winding the primary yarn;

the wiredrawing in the step (1) is to spray the Gao Nianju amide 56 melt through a spinneret plate of a spinning box body to form the primary wiredrawing;

the temperature of the spinning box body is 287 ℃;

the pressure of the spinning component in the spinning box body is 13MPa;

the spinneret draw ratio of the spinneret plate is 85;

the specification of the filter screen in the spinning component is 350 meshes, and the specification of the metal sand in the spinning component is 60 meshes;

the conveying length of the melt pipeline from the melt booster pump to the spinning box body of the Gao Nianju amide 56 melt is 24m;

the residence time of the melt of the Gao Nianju amide 56 from the melt booster pump to the spinning manifold is 16min;

the cooling is a side blowing wind, the wind speed is 0.6m/s, the wind temperature is 17 ℃, and the humidity is 85%;

the pre-network pressure is 1.3bar;

the stretching process adopts 6 pairs of hot rolls and is divided into five stages of stretching, and the stretching process is as follows: the primary yarn after oiling is firstly fed into a first pair of hot rolls, first-stage pre-stretching is carried out between the first pair of hot rolls and a second pair of hot rolls, then second-stage main stretching is carried out between the second pair of hot rolls and a third pair of hot rolls, third-stage main stretching is carried out between the third pair of hot rolls and a fourth pair of hot rolls, tension heat setting is carried out, fourth-stage stretching is carried out between the fourth pair of hot rolls and a fifth pair of hot rolls, first relaxation heat setting is carried out, and fifth-stage stretching is carried out between the fifth pair of hot rolls and a sixth pair of hot rolls, and second relaxation heat setting is carried out; and finally, adopting a winding head to wind.

Wherein the speed of the first pair of hot rollers is 480m/min, and the temperature is 45 ℃;

the speed of the second pair of hot rollers is 530m/min, and the temperature is 90 ℃;

the speed of the third pair of hot rollers is 1850m/min, and the temperature is 190 ℃;

the speed of the fourth pair of hot rollers is 2500m/min, and the temperature is 215 ℃;

the speed of the fifth pair of hot rollers is 2400m/min, and the temperature is 180 ℃;

the speed of the sixth pair of hot rollers is 2350m/min, and the temperature is 130 ℃;

the total stretch factor of the stretching is 5.21;

the speed retraction size of the heat roller of the 4 th pair and the heat roller of the 5 th pair is 100m/min;

the speed retraction size of the 5 th pair and the 6 th pair of hot rolls is 50m/min;

the main network pressure is 3.0bar;

the winding tension at the time of the winding forming is 30cN;

the winding speed is 2300m/min; the winding overfeed ratio is 2.1%;

and a humidifying device is arranged in the retracting and winding process, the humidifying temperature is 22 ℃, and the humidity is 86%.

The polyamide 56 balloon yarn of this example had an annual output of 1.5 ten thousand tons/yarn, a spinning position of 48 bits/yarn and a number of 8 bits/bit.

Example 2 high strength yarn for polyamide 56 air bag yarn of 420dtex/68f gauge

Preparation of highly viscous polyamide 56 melt

wherein the molar ratio of the 1, 5-pentanediamine to the adipic acid is 1.05:1, a step of; the concentration of the polyamide 56 salt solution is 53wt%; the pH value of the polyamide 56 salt solution is 8.2;

the pre-polymerization pressure is 1.7MPa, and the pre-polymerization temperature is 254 ℃;

the pressure of the polycondensation is-0.04 MPa, and the temperature of the polycondensation is 285 ℃;

the Gao Nianju amide 56 melt has a copper ion content of 75ppm, a relative viscosity of 3.2, an oligomer content of 0.6wt%, an amino content of 38mmol/kg and a balance water content of 400ppm.

Preparation of high-strength yarn for polyamide 56 air bag yarn

The temperature of the spinning box body is 285 ℃;

the pressure of the spinning component in the spinning box body is 12MPa;

the spinneret draw ratio of the spinneret plate is 60;

the specification of the filter screen in the spinning component is 300 meshes, and the specification of the metal sand in the spinning component is 45 meshes;

the conveying length of the melt pipeline from the melt booster pump to the spinning box body of the Gao Nianju amide 56 melt is 28m;

the residence time of the melt of the Gao Nianju amide 56 from the melt booster pump to the spinning manifold is 15min;

the cooling is a side blowing wind, the wind speed is 0.63m/s, the wind temperature is 18 ℃, and the humidity is 85%;

the pre-network pressure is 1.5bar;

the stretching process adopts 6 pairs of hot rolls and is divided into five stages of stretching, and the stretching process is as follows: the primary yarn after oiling is firstly fed into a first pair of hot rolls, first-stage pre-stretching is carried out between the first pair of hot rolls and a second pair of hot rolls, then second-stage main stretching is carried out between the second pair of hot rolls and a third pair of hot rolls, third-stage main stretching is carried out between the third pair of hot rolls and a fourth pair of hot rolls, tension heat setting is carried out, fourth-stage stretching is carried out between the fourth pair of hot rolls and a fifth pair of hot rolls, first relaxation heat setting is carried out, and fifth-stage stretching is carried out between the fifth pair of hot rolls and a sixth pair of hot rolls, and second relaxation heat setting is carried out; finally, adopting a winding head to wind;

Wherein the speed of the first pair of hot rollers is 480m/min, and the temperature is 50 ℃;

the speed of the second pair of hot rollers is 520m/min, and the temperature is 95 ℃;

the speed of the third pair of hot rollers is 1900m/min, and the temperature is 190 ℃;

the speed of the fourth pair of hot rollers is 2600m/min, and the temperature is 220 ℃;

the speed of the fifth pair of hot rollers is 2550m/min, and the temperature is 190 ℃;

the speed of the sixth pair of hot rollers is 2450m/min, and the temperature is 120 ℃;

the total stretch factor of the stretching is 5.42;

the speed retraction size of the heat roller of the 4 th pair and the 5 th pair is 50m/min;

the speed retraction size of the 5 th pair and the 6 th pair of hot rolls is 100m/min;

the main network pressure is 3.0bar;

the winding tension during the winding forming is 40cN;

the winding speed is 2400m/min; the winding overfeed ratio is 2.1%;

and a humidifying device is arranged in the retracting and winding process, the humidifying temperature is 19 ℃, and the humidity is 85%.

The polyamide 56 balloon yarn according to this example had an annual output of 2.0 ten thousand tons/yarn, a spinning position of 48 bits/yarn and a number of 8 bits/bit.

Example 3 high strength yarn for polyamide 56 balloon yarn of 470dtex/86f

Preparation of highly viscous polyamide 56 melt

wherein the molar ratio of the pentylene diamine to the adipic acid is 1.05:1, a step of; the concentration of the polyamide 56 salt solution is 54wt%; the pH value of the polyamide 56 salt solution is 7.9;

the pre-polymerization pressure is 1.78MPa, and the pre-polymerization temperature is 248 ℃;

the pressure of the polycondensation is-0.05 MPa, and the temperature of the polycondensation is 280 ℃;

adding a heat stabilizer in the form of heat-resistant master batch through a master batch online adding device and a dynamic mixer in the melt polymerization process of the polyamide 56, wherein the heat stabilizer is compounded by cuprous iodide and potassium iodide, the content of copper ions in the heat-resistant master batch is 4wt%, and the adding amount of the heat-resistant master batch is 0.15wt% of the total weight of the production raw materials;

the resulting high-viscosity polyamide 56 melt had a copper ion content of 60ppm, a relative viscosity of 3.3, an oligomer content of 0.6wt%, an amino content of 38mmol/kg and an equilibrium moisture content of 300ppm.

Preparation of high-strength yarn for polyamide 56 air bag yarn

the temperature of the spinning box body is 285 ℃;

the pressure of the spinning component in the spinning box body is 12MPa;

the spinneret draw ratio of the spinneret plate is 70;

the specification of the filter screen in the spinning component is 400 meshes, and the specification of the metal sand in the spinning component is 60 meshes;

the conveying length of the melt pipeline from the melt booster pump to the spinning box body of the Gao Nianju amide 56 melt is 29m;

the residence time of the melt of the Gao Nianju amide 56 from the melt booster pump to the spinning manifold is 18min;

the cooling is a side blowing wind, the wind speed is 0.62m/s, the wind temperature is 18 ℃, and the humidity is 90%;

the pre-network pressure is 1.5bar;

Wherein the speed of the first pair of hot rollers is 600m/min, and the temperature is 30 ℃;

the speed of the second pair of hot rollers is 630m/min, and the temperature is 110 ℃;

the speed of the third pair of hot rollers is 1800m/min, and the temperature is 185 ℃;

the speed of the fourth pair of hot rollers is 3000m/min, and the temperature is 220 ℃;

the speed of the fifth pair of hot rollers is 2950m/min, and the temperature is 195 ℃;

the speed of the sixth pair of hot rollers is 2850m/min, and the temperature is 150 ℃;

the total stretching multiple of the stretching is 5.0;

the main network pressure is 3.0bar;

the winding tension during the winding forming is 40cN;

the winding speed is 2800m/min; the winding overfeed ratio is 1.8%;

and a humidifying device is arranged in the retracting and winding process, the humidifying temperature is 21 ℃, and the humidity is 85%.

The polyamide 56 balloon yarn according to this example had an annual output of 2.0 ten thousand tons/yarn, a spinning position of 48 bits/yarn and a number of spinning heads of 6 bits/yarn.

Example 4 Polyamide 56 balloon yarn with a gauge of 585dtex/136f high strength yarn

Preparation of highly viscous polyamide 56 melt

Preparing a polyamide 56 salt solution from pentanediamine, adipic acid and water, and then carrying out prepolymerization, flash evaporation and polycondensation to obtain a polyamide 56 melt;

wherein the molar ratio of the pentanediamine to the adipic acid is 1.04:1; the concentration of the polyamide 56 salt solution is 54wt%; the pH value of the polyamide 56 salt solution is 7.8;

the pre-polymerization pressure is 1.73MPa, and the pre-polymerization temperature is 245 ℃;

the pressure of the polycondensation is-0.04 MPa, and the temperature of the polycondensation is 286 ℃;

the Gao Nianju amide 56 melt has a copper ion content of 68ppm, a relative viscosity of 3.1, an oligomer content of 0.6wt%, an amino content of 45mmol/kg and a balance water content of 500ppm.

Preparation of high-strength yarn for polyamide 56 air bag yarn

The temperature of the spinning box body is 285 ℃;

the pressure of the spinning component in the spinning box body is 12MPa;

the spinneret draw ratio of the spinneret plate is 65;

the specification of the filter screen in the spinning component is 350 meshes, and the specification of the metal sand in the spinning component is 45 meshes;

the conveying length of the melt pipeline from the melt booster pump to the spinning box body of the Gao Nianju amide 56 melt is 26m;

the cooling is a side blowing wind, the wind speed is 0.64m/s, the wind temperature is 19 ℃, and the humidity is 80%;

the pre-network pressure is 1.5bar;

the speed of the second pair of hot rollers is 630m/min, and the temperature is 100 ℃;

the speed of the third pair of hot rollers is 1850m/min, and the temperature is 180 ℃;

the speed of the fourth pair of hot rollers is 3100m/min, and the temperature is 220 ℃;

the speed of the fifth pair of hot rollers is 2950m/min, and the temperature is 190 ℃;

the speed of the sixth pair of hot rollers is 2900m/min, and the temperature is 150 ℃;

the total stretch factor of the stretching is 5.2;

the speed retraction size of the heat roller of the 4 th pair and the 5 th pair is 150m/min;

the main network pressure is 3.0bar;

the winding tension during the winding forming is 50cN;

the winding speed is 2860m/min; the winding overfeed ratio is 1.4%;

and a humidifying device is arranged in the retracting and winding process, the humidifying temperature is 20 ℃, and the humidity is 88%.

The polyamide 56 balloon yarn of this example had an annual output of 1.3 ten thousand tons/yarn, a spinning position of 24 bits/yarn and a number of spinning heads of 6 bits/yarn.

Example 5 high strength yarn for polyamide 56 air bag yarn of 630dtex/106f gauge

Preparation of highly viscous polyamide 56 melt

wherein the molar ratio of the pentanediamine to the adipic acid is 1.05:1; the concentration of the polyamide 56 salt solution is 52wt%; the pH value of the polyamide 56 salt solution is 7.9;

the pre-polymerization pressure is 1.72MPa, and the pre-polymerization temperature is 252 ℃;

the pressure of the polycondensation is-0.06 MPa, and the temperature of the polycondensation is 285 ℃;

the Gao Nianju amide 56 melt has a copper ion content of 65ppm, a relative viscosity of 3.3, an oligomer content of 0.7wt%, an amino content of 35mmol/kg and a balance water content of 400ppm.

Preparation of high-strength yarn for polyamide 56 air bag yarn

The temperature of the spinning box body is 284 ℃;

the pressure of the spinning component in the spinning box body is 13MPa;

the spinneret draw ratio of the spinneret plate is 60;

the specification of the filter screen in the spinning component is 250 meshes, and the specification of the metal sand in the spinning component is 80 meshes;

the residence time of the melt of the Gao Nianju amide 56 from the melt booster pump to the spinning manifold is 14min;

the cooling is a side blowing wind, the wind speed is 0.58m/s, the wind temperature is 18 ℃, and the humidity is 85%;

the pre-network pressure is 1.4bar;

Wherein the speed of the first pair of hot rollers is 500m/min, and the temperature is 30 ℃;

the speed of the second pair of hot rollers is 550m/min, and the temperature is 100 ℃;

the speed of the third pair of hot rollers is 1800m/min, and the temperature is 180 ℃;

the speed of the fifth pair of hot rollers is 2900m/min, and the temperature is 190 ℃;

the speed of the sixth pair of hot rollers is 2800m/min, and the temperature is 150 ℃;

the total stretch factor of the stretching is 5.6;

the main network pressure is 3.0bar;

the winding tension during the winding forming is 60cN;

the winding speed is 2750m/min; the winding overfeed ratio is 1.8%;

The polyamide 56 balloon yarn of this example had an annual output of 1.3 ten thousand tons/yarn, a spinning position of 36 bits/yarn and a number of spinning heads of 4 bits/yarn.

Example 6 high strength yarn for polyamide 56 air bag yarn of 700dtex/105f gauge

Preparation of highly viscous polyamide 56 melt

wherein the molar ratio of the pentanediamine to the adipic acid is 1.08:1; the concentration of the polyamide 56 salt solution is 56wt%; the pH value of the polyamide 56 salt solution is 8.2;

the pre-polymerization pressure is 1.7MPa, and the pre-polymerization temperature is 248 ℃;

the pressure of the polycondensation is-0.06 MPa, and the temperature of the polycondensation is 283 ℃;

the Gao Nianju amide 56 melt has a copper ion content of 60ppm, a relative viscosity of 3.4, an oligomer content of 0.6wt%, an amino content of 32mmol/kg and a balance water content of 500ppm.

Preparation of high-strength yarn for polyamide 56 air bag yarn

The temperature of the spinning box body is 283 ℃;

the pressure of the spinning component in the spinning box body is 11MPa;

the spinneret draw ratio of the spinneret is 58;

the specification of the filter screen in the spinning component is 300 meshes, and the specification of the metal sand in the spinning component is 60 meshes;

the cooling is a side blowing wind, the wind speed is 0.63m/s, the wind temperature is 19 ℃, and the humidity is 82%;

the pre-network pressure is 1.3bar;

the speed of the second pair of hot rollers is 550m/min, and the temperature is 110 ℃;

the speed of the fourth pair of hot rollers is 3000m/min, and the temperature is 2210 ℃;

the speed of the fifth pair of hot rollers is 2900m/min, and the temperature is 1890 ℃;

the speed of the sixth pair of hot rollers is 2850m/min, and the temperature is 1530 ℃;

the total stretch factor of the stretching is 5.7;

the main network pressure is 3.0bar;

the winding tension during the winding forming is 65cN;

the winding speed is 2800m/min; the winding overfeed ratio is 1.8%;

and a humidifying device is arranged in the retracting and winding process, the humidifying temperature is 20 ℃, and the humidity is 85%.

The polyamide 56 balloon yarn of this example had an annual output of 1.5 ten thousand tons/yarn, a spinning position of 24 bits/yarn and a number of spinning heads of 6 bits/bit.

Example 7

A polyamide 56 balloon yarn was produced by the same process as in example 2, except that the relative viscosity of the Gao Nianju amide 56 melt was 2.55.

Example 8

The same process as in example 2 was used to prepare a high strength yarn for polyamide 56 balloon yarns, except that the Gao Nianju amide 56 melt balance moisture content was 1200ppm.

Example 9

The same process as in example 2 was used to prepare a high strength yarn for polyamide 56 balloon yarns, except that the Gao Nianju amide 56 melt was transported in a melt pipe length of 58m from the melt booster pump to the spinning beam.

Example 10

The same process as in example 2 was used to prepare a high strength yarn for polyamide 56 balloon yarns, except that the melt residence time of the Gao Nianju amide 56 melt from the melt booster pump to the spinning beam was 52 minutes.

Example 11

The same process as in example 2 was used to prepare a high strength yarn for polyamide 56 balloon yarns, except that no heat stabilizer was added during the polymerization.

Example 12

A high-strength yarn for polyamide 56 air bag yarn was produced by the same process as in example 2, except that the amount of the heat stabilizer added was controlled so that the copper ion content in the Gao Nianju amide 56 melt was 35ppm.

Example 13

A high strength yarn for polyamide 56 air bag yarn was produced by the same process as in example 2, except that the oligomer content of the melt of Gao Nianju amide 56 was 1.4% by weight.

Example 14

The same process as in example 2 was used to prepare a high strength yarn for polyamide 56 air bag yarn, except that the filter screen in the spin pack assembly had a 1000 mesh size and the metal sand had a 120 mesh size.

Example 15

The same process as in example 2 was used to prepare a high strength yarn for polyamide 56 balloon yarns, except that no humidifying device was used during retraction and winding.

Comparative example 1

The same process as in example 2 was used to prepare a high-strength yarn for polyamide 56 air bag yarn, except that the high-viscosity polyamide 56 melt obtained in step (1) was first pelletized and dried to obtain a chip, and the chip was melted by a single screw and fed to a spinning box through a melt feed line, and the chip was spun to prepare a high-strength yarn for polyamide 56 air bag yarn.

Table 1 high strength yarn parameters for polyamide 56 balloon yarns prepared in examples and comparative examples

By adopting the preparation method of the high-strength yarn for the polyamide 56 air bag yarn, the parameters such as the conveying length of a melt pipeline, the residence time of the melt and the like are controlled by optimizing the melt direct spinning process, so that the melt of the polyamide 56 can be stable, the viscosity and the amino fluctuation are small, the production of the high-strength yarn for the high-capacity polyamide 56 air bag yarn can be realized, the high-strength yarn for the polyamide 56 air bag yarn has the properties of high strength, heat resistance and less hairiness, and the gel content of a melt booster pump in a spinning box body can be effectively reduced.

The previous description of the embodiments is provided to facilitate a person of ordinary skill in the art in order to make and use the present invention. It will be apparent to those skilled in the art that various modifications can be readily made to these embodiments and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above-described embodiments, and those skilled in the art, based on the present disclosure, should make improvements and modifications without departing from the scope of the present invention.

Claims

1. The high-strength yarn for the polyamide 56 airbag yarn is characterized in that the fineness of the high-strength yarn for the polyamide 56 airbag yarn is 200-800dtex, further 300-750dtex and further 350-700dtex; and/or

The content of copper ions in the high-strength wire for the polyamide 56 air bag wire is 50-120ppm, further 55-110ppm and still further 60-100ppm.

2. A method for preparing the high-strength yarn for the polyamide 56 air bag yarn according to claim 1, wherein the preparation method at least comprises the following steps:

3. The method of claim 2, wherein in step (1), the Gao Nianju amide 56 melt has a relative viscosity of 3.0 to 4.0, preferably 3.1 to 3.8, more preferably 3.2 to 3.6; and/or

The amino group content of the Gao Nianju amide 56 melt is 30-60mmol/kg, preferably 33-50mmol/kg, and more preferably 35-45mmol/kg; and/or

The equilibrium moisture content of the Gao Nianju amide 56 melt is 200-800ppm, preferably 300-700ppm, and more preferably 350-500ppm; and/or

The content of copper ions in the Gao Nianju amide 56 melt is 50-120ppm, preferably 55-110ppm, and more preferably 60-100ppm; and/or

The oligomer content of the Gao Nianju amide 56 melt is 1.1wt% or less, preferably 1.0wt% or less, more preferably 0.9wt% or less, and even more preferably 0.8wt% or less.

4. The preparation method according to claim 2, wherein the length of the melt pipe conveying the Gao Nianju amide 56 melt from the melt booster pump to the spinning beam is 10-50m, preferably 13-45m, more preferably 15-40m, even more preferably 18-35m.

5. The preparation method according to claim 2, wherein the melt residence time of the Gao Nianju amide 56 melt from the melt booster pump to the spinning beam is 6-45min, preferably 8-40min, further preferably 10-35min, still further preferably 12-30min.

6. The method of preparing according to claim 2, wherein the method of preparing Gao Nianju amide 56 melt comprises the steps of: preparing a polyamide 56 salt solution from pentanediamine, adipic acid and water, and then carrying out prepolymerization, flash evaporation and polycondensation to obtain a polyamide 56 melt;

Wherein the pressure of the prepolymerization is 0.8-2.6MPa, preferably 1.0-2.4MPa, more preferably 1.3-2.2MPa, still more preferably 1.5-2.0MPa; the temperature of the prepolymerization is 180-275 ℃, preferably 190-270 ℃, more preferably 210-265 ℃, still more preferably 225-260 ℃;

the pressure of the polycondensation is- (0-0.08) MPa, preferably- (0.02-0.07) MPa, more preferably- (0.03-0.06) MPa, still more preferably- (0.04-0.05) MPa; the temperature of the polycondensation is 265 to 295 ℃, preferably 270 to 293 ℃, more preferably 275 to 290 ℃, still more preferably 278 to 288 ℃.

7. The preparation method according to claim 6, wherein the heat stabilizer is added during the polymerization of the pentanediamine and the adipic acid, or is added in the form of heat-resistant master batch by a master batch on-line adding device and a dynamic mixer device;

the heat stabilizer is selected from any one or more of copper acetate, potassium iodide, potassium bromide, copper chloride, cuprous iodide, cupric oxide and cuprous oxide, preferably copper acetate and potassium iodide or cuprous iodide and potassium iodide.

8. The method of claim 2 wherein the drawing in step (1) is by spraying the melt of polyamide 56 through a spinneret of a spinning beam to form the primary filaments;

The temperature of the spinning box body is 280-300 ℃, preferably 283-295 ℃, more preferably 285-293 ℃; and/or

The pressure of the spinning component in the spinning box body is more than or equal to 10MPa, more preferably more than or equal to 11MPa, and still more preferably more than or equal to 12MPa; and/or

Further, the specification of the filter screen in the spinning component is 100-600 meshes, further 200-550 meshes and further 300-500 meshes; and/or

The specification of the metal sand in the spinning component is 30-100 meshes, more preferably 40-80 meshes, and still more preferably 45-60 meshes.

9. The method according to claim 2, wherein in the step (2), the multistage stretching process is performed using five pairs of hot rolls or more, preferably six pairs of hot rolls, and the stretching process is performed in five stages, and the stretching process is: feeding the oiled primary yarn into a first pair of hot rolls, pre-stretching the primary yarn for the first time between the first pair of hot rolls and a second pair of hot rolls, performing primary stretching for the second time between the second pair of hot rolls and a third pair of hot rolls, performing primary stretching for the third time between the third pair of hot rolls and a fourth pair of hot rolls, performing tension heat setting, performing primary stretching for the fourth time between the fourth pair of hot rolls and a fifth pair of hot rolls, performing primary relaxation heat setting, performing secondary stretching for the fifth time between the fifth pair of hot rolls and a sixth pair of hot rolls, performing secondary relaxation heat setting, and finally performing winding forming by adopting a winding head;

The pre-network pressure is 1-2.5bar, preferably 1.5-2.0bar;

the main network pressure is 2.5-4.5bar, preferably 3.0-3.5bar;

the speed retraction size of the fourth pair of hot rolls and the fifth pair of hot rolls is 30-200m/min, preferably 50-150m/min;

the speed retraction size of the fifth pair and the sixth pair of hot rolls is 30-200m/min, preferably 50-150m/min;

the winding tension at the time of the winding forming is 20 to 100cN, preferably 30 to 80cN, more preferably 40 to 70cN;

the winding speed is 2200-3300m/min, preferably 2400-3250m/min, more preferably 2500-3200m/min; the winding overfeed ratio is 0.5-5%, preferably 1.0-4%, more preferably 1.3-3%.

10. The method of claim 9, wherein a humidifying device is provided during the retracting and winding process, the humidifying temperature being 18-30 ℃, preferably 20-28 ℃, more preferably 22-26 ℃; the humidity is 60 to 95%, preferably 65 to 90%, more preferably 70 to 85%.