CN111411405B

CN111411405B - High-strength polyamide 56 industrial yarn and preparation method and application thereof

Info

Publication number: CN111411405B
Application number: CN202010245848.6A
Authority: CN
Inventors: 孙朝续; 陈万钟; 刘修才
Original assignee: Cathay Wusu Biomaterial Co ltd; Cathay R&D Center Co Ltd; CIBT America Inc
Current assignee: Cathay Wusu Biomaterial Co ltd; Cathay R&D Center Co Ltd; CIBT America Inc
Priority date: 2020-03-31
Filing date: 2020-03-31
Publication date: 2021-09-28
Anticipated expiration: 2040-03-31
Also published as: CN111411405A

Abstract

本发明提供了一种高强聚酰胺56工业丝及其制备方法与应用。所述高强聚酰胺56工业丝的制备方法为将高粘聚酰胺56树脂加热至熔融状态，制得聚酰胺56熔体，通过熔体管道输送到纺丝箱体中进行拉丝，将制得的初生丝进行保温、冷却、上油、预网络、多级拉伸、紧张定型、松弛定型、主网络、卷绕，最终得到所述高强聚酰胺56工业丝。本发明提供的高强聚酰胺56工业丝具有较好的力学性能与耐湿热性能，可应用于缝纫线、轮胎帘子线、气囊丝、脱模布、水布、帆布、安全带、绳索、渔网、工业过滤布、传输带、降落伞、帐篷、箱包领域。The invention provides a high-strength polyamide 56 industrial yarn and a preparation method and application thereof. The preparation method of the high-strength polyamide 56 industrial yarn is to heat the high-viscosity polyamide 56 resin to a molten state to obtain a polyamide 56 melt, which is transported into a spinning box through a melt pipeline for drawing, and the obtained The spun silk is subjected to heat preservation, cooling, oiling, pre-interlacing, multi-stage stretching, tension setting, relaxation setting, main meshing, and winding, and finally the high-strength polyamide 56 industrial silk is obtained. The high-strength polyamide 56 industrial yarn provided by the invention has good mechanical properties and moisture-heat resistance properties, and can be applied to sewing threads, tire cords, airbag yarns, mold release cloths, water cloths, canvases, safety belts, ropes, fishing nets, Industrial filter cloth, conveyor belt, parachute, tent, luggage field.

Description

High-strength polyamide 56 industrial yarn and preparation method and application thereof

Technical Field

The invention belongs to the technical field of polyamide materials, and relates to a high-strength polyamide 56 industrial yarn and a preparation method and application thereof.

Background

The terylene and the chinlon high-strength yarn have the characteristics of high strength, low elongation, good dimensional stability, fatigue resistance, aging resistance and the like, so that the terylene and the chinlon high-strength yarn are widely applied to the fields of tire cords, canvases, transmission belts, safety air bags, parachutes, ropes, safety belts, industrial filter cloth or tents and the like.

The production process of the high-strength yarn comprises two processes: one is a direct spinning method adopting melt tackifying, and the other is an indirect spinning method adopting slice solid tackifying.

At present, the high-strength yarn mainly comprises polyester, polyamide 6 and polyamide 66, and the research on the high-strength polyamide 56 industrial yarn is relatively less.

Patent number CN 106868624B discloses a polyamide 5X high-strength yarn and a preparation method thereof, wherein the breaking strength of the polyamide 5X high-strength yarn is 8.0-10.0cN/dtex, the elongation at break is 10-15%, and the elongation at break of the polyamide 5X high-strength yarn is lower. Patent No. CN 106835329B discloses a polyamide 5X medium-strength filament and a preparation method thereof, wherein the breaking strength of the polyamide 5X medium-strength filament is 6.0-8.0cN/dtex, the elongation at break is 20.8-25%, and the breaking strength of the polyamide 5X medium-strength filament is low. Patent CN 110055602A discloses a polyamide 56 high-tenacity industrial yarn and a preparation method thereof, a high-speed winding low-power drafting process is adopted, the winding speed is more than 4000m/min, and the total drafting multiplying factor is 1.90-2.85. The high-strength industrial yarn is prepared by a high-power drafting and low-speed winding process, the drafting multiple is more than or equal to 4.0 times, and the winding speed is less than or equal to 3500 m/min. The high-speed winding low-power drawing process is adopted, the winding speed is higher than 4000m/min, the drawing multiple is smaller than 3.0, the winding speed is high, the retention time on different hot rollers in the fiber drawing process is relatively shortened, namely the high-temperature setting time of the fiber is shortened, and then the low-power drawing process is adopted, so that the fiber crystallization and orientation are relatively low, and the breaking strength and the dimensional stability of the prepared fiber are relatively low.

Disclosure of Invention

The first purpose of the invention is to provide a high-strength and damp-heat resistant polyamide 56 industrial yarn.

The high-strength polyamide 56 industrial yarn has high mechanical property and good humidity resistance, the breaking strength is more than or equal to 8.2cN/dtex, the breaking strength retention rate after water bath treatment is more than or equal to 88 percent, the elongation at break is less than or equal to 33 percent, and the elongation fluctuation is less than or equal to 10 percent; the breaking strength retention rate of the industrial yarn after humidity conditioning treatment is more than or equal to 90 percent, the breaking elongation is less than or equal to 27 percent, and the elongation fluctuation is less than or equal to 3 percent.

The second purpose of the invention is to provide a preparation method of the high-strength polyamide 56 industrial yarn.

By optimizing the spinning process, adjusting the spinning temperature and the assembly pressure, increasing the slow cooling device, the cooling process, the oiling device, the pressure of the pre-network and the main network, the drafting process, the shaping process and the winding process, the spinnability of the polyamide 56 industrial yarn is improved, the filament breakage times and the number of broken filaments in the production process are reduced, and the production efficiency is improved.

The third purpose of the invention is to provide the application of the high-strength polyamide 56 industrial yarn.

In order to achieve the above purpose, the solution of the invention is as follows:

the invention provides a high-strength polyamide 56 industrial yarn, which has the breaking strength of 8.2-10.0 cN/dtex, preferably 8.4-9.6 cN/dtex, and more preferably 8.7-9.2 cN/dtex; and/or the presence of a gas in the gas,

after the water bath treatment, the breaking strength retention rate of the high-strength polyamide 56 industrial yarn is more than or equal to 88%, preferably more than or equal to 90%, and more preferably more than or equal to 92%; and/or the presence of a gas in the gas,

after the industrial yarn moisture-conditioning treatment, the breaking strength retention rate of the high-strength polyamide 56 industrial yarn is not less than 90%, preferably not less than 93%, and more preferably not less than 95%.

Preferably, the breaking elongation of the high-strength polyamide 56 industrial yarn is 16-24%, preferably 18-22%, and more preferably 19-20%; and/or the presence of a gas in the gas,

after the water bath treatment, the breaking elongation of the high-strength polyamide 56 industrial yarn is less than or equal to 33 percent, preferably less than or equal to 28 percent, and more preferably less than or equal to 25 percent; the elongation fluctuation is less than or equal to 10 percent, preferably less than or equal to 8 percent, and more preferably less than or equal to 6 percent; and/or the presence of a gas in the gas,

after the industrial yarn is subjected to humidity adjustment treatment, the breaking elongation of the high-strength polyamide 56 industrial yarn is less than or equal to 27%, preferably less than or equal to 26%, and more preferably less than or equal to 25%; the elongation fluctuation is 3% or less, preferably 2% or less, more preferably 1% or less.

Preferably, the water bath treatment temperature is 70-110 ℃, preferably 75-100 ℃, more preferably 80-90 ℃, and the water bath treatment time is 20-60 min, preferably 30-50 min; and/or the humidity adjusting temperature is 18-30 ℃, preferably 20-27 ℃, the humidity adjusting humidity is 60-95%, and the humidity adjusting time is 1-48 h, preferably 4-40 h, and more preferably 8-30 h.

Preferably, the conditions of the water bath treatment are as follows: the treatment temperature is 90 ℃, and the treatment time is 30 min; and/or the presence of a gas in the gas,

the conditions of the industrial yarn moisture-adjusting treatment are as follows: the treatment temperature is 20 ℃, the treatment humidity is 65%, and the treatment time is 24 h.

In some preferred embodiments of the invention, the number of times of filament breakage of the high-strength polyamide 56 industrial filament is less than or equal to 4 per 24 hours, preferably less than or equal to 2 per 24 hours, and more preferably less than or equal to 1 per 24 hours; and/or the presence of a gas in the gas,

the broken filaments of the high-strength polyamide 56 industrial yarn are less than or equal to 8/10 kg packages, preferably less than or equal to 6/10 kg packages, and more preferably less than or equal to 4/10 kg packages.

The production raw materials of the high-strength polyamide 56 industrial yarn comprise 1, 5-pentanediamine and adipic acid; alternatively, the polyamide resin 56 may be obtained by polymerizing 1, 5-pentanediamine and adipic acid as monomers, wherein the pentanediamine may be chemically or biologically derived 1, 5-pentanediamine, and preferably is biologically derived 1, 5-pentanediamine.

In another aspect of the present invention, a method for preparing a high-strength polyamide 56 industrial yarn is also provided, which comprises the following steps:

(1) heating high-viscosity polyamide 56 resin to a molten state to prepare polyamide 56 melt;

(2) conveying the polyamide 56 melt prepared in the step (1) to a spinning manifold through a melt pipeline for drawing to prepare a primary yarn;

(3) and (3) carrying out heat preservation, cooling, oiling, pre-networking, multi-stage stretching, tension sizing, relaxation sizing, main networking and winding on the primary yarn prepared in the step (2) to obtain the high-strength polyamide 56 industrial yarn.

In some preferred embodiments of the present invention, the relative viscosity of the 96% sulfuric acid of the high viscosity polyamide 56 resin in step (1) is 3.3 to 4.0, preferably 3.4 to 3.8, and more preferably 3.5 to 3.6; and/or the presence of a gas in the gas,

the water content of the high-viscosity polyamide 56 resin is 300-550 ppm, preferably 350-500 ppm, and more preferably 400-450 ppm.

In other preferred embodiments of the present invention, the drawing in step (2) is performed by ejecting the melt of the polyamide 56 obtained in step (1) through a spinneret of a spinning beam to obtain the as-spun yarn; and/or the presence of a gas in the gas,

the temperature of the spinning manifold is 280-295 ℃, preferably 283-293 ℃, and more preferably 285-290 ℃; and/or the presence of a gas in the gas,

the pressure of a spinning assembly of the spinning manifold is 13-25 MPa, preferably 15-20 MPa, and more preferably 17-18 MPa.

In other preferred embodiments of the present invention, in the step (3), a slow cooling device is adopted for heat preservation, the slow cooling device is a hot jacket which is arranged at the lower part of the spinneret plate and is closely adjacent to the spinneret plate, so as to ensure that the nascent fiber is uniformly and slowly cooled, the length and temperature of the hot jacket are changed along with the specification of the spinneret plate and the fineness of the filament bundle, wherein the slow cooling height refers to the thickness of the hot jacket, and the slow cooling height is 100-350 mm, preferably 200-300 mm; the slow cooling temperature refers to the ambient temperature around the tows, and is 250-320 ℃, preferably 250-300 ℃; and/or the presence of a gas in the gas,

the cooling is air cooling by cross air blowing or circular air blowing, and the air cooling speed is 0.4-0.9 m/s, preferably 0.6-0.8 m/s; the air temperature of the air cooling is 16-25 ℃, and preferably 18-22 ℃; the air-cooled air humidity is 60-90%, and preferably 75-85%; and/or the presence of a gas in the gas,

the concentration of the oil agent used in oiling is 8-100 wt%, and preferably 65-100 wt%, and the dynamic viscosity of the oil agent is less than or equal to 300mPas, preferably less than or equal to 200mPas, and more preferably less than or equal to 100 mPas. In one embodiment, the finish is selected from one or more of N-350 (available from Nippon Songbo oil pharmaceuticals Co., Ltd.), N-353 (available from Nippon Songbo oil pharmaceuticals Co., Ltd.), NEO TEX-903(A) (available from Shanghai Bikame chemical Co., Ltd.), D-3088 (available from Nantong Henrun chemical Co., Ltd.), dakaoNeat finish (available from Dakoku K.K.), TCP-60 Chinlon industrial filament/cord finish (available from Tianjin chemical Co., Ltd.), TCP-80 Chinlon industrial filament/cord finish (available from Tianjin chemical Co., Ltd.), TC1152 (available from German Sesamer chemical company Zschimmer & Schwarz), TC1355 (available from German Sesamer chemical company Zschwarmer & Schwarz), TC-14686 (available from GouldSTON TECHNOLOGIES, Inc., 700North Johnson St., Monroe, NC 28110, N), and more preferably, further more preferably, TC1355, One or more of TC-14686, TCP-60 and TCP-80; and/or the presence of a gas in the gas,

the oiling comprises the mode of oiling by adopting an oil nozzle, an oil tanker or an oil lip, for example, 2 or more oil nozzles, oil tankers or oil lips are adopted for oiling, and 2 oil nozzles are preferably adopted for oiling; and/or the height of the oil nozzle from the spinneret plate is more than or equal to 3m, preferably more than or equal to 3.5m, and more preferably more than or equal to 4 m; and/or the width of the oil nozzle is 8-25 mm, preferably 10-22 mm, and more preferably 12-18 mm; and/or the oiling rate is 0.6-2.0%, preferably 0.8-1.5%, and more preferably 1.0-1.2%; and/or the presence of a gas in the gas,

the pre-network pressure is 1-2.5 bar, preferably 1.5-2.0 bar; and/or the presence of a gas in the gas,

the stretching process adopts 5 pairs of hot rollers and is divided into four stages of stretching, and the stretching process comprises the following steps: feeding oiled nascent yarn to a first pair of hot rollers, performing primary pre-stretching between the first pair of hot rollers and a second pair of hot rollers, performing secondary main stretching between the second pair of hot rollers and a third pair of hot rollers, performing tertiary main stretching between the third pair of hot rollers and a fourth pair of hot rollers and performing tension heat setting, and performing fourth-stage secondary stretching between the fourth pair of hot rollers and a fifth pair of hot rollers and performing relaxation heat setting;

among them, preferred are: the stretching ratio of the first-stage stretching is 1.0-1.1; and/or the stretching multiple of the second-stage stretching is 3.0-4.0; and/or the stretching multiple of the third stage stretching is 1.3-1.6; and/or the stretching multiple of the fourth stage stretching is 0.9-1.0; and/or the total stretching multiple of the stretching is preferably 4.5-6.0;

and/or the temperature of the tension heat setting is 180-230 ℃, preferably 200-220 ℃; and/or the temperature of the relaxation heat setting is 120-200 ℃, preferably 140-180 ℃; and/or the speed retraction of the fourth heat roller pair and the fifth heat roller pair is 50-200 m/min, preferably 100-150 m/min;

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

and/or the winding speed is 2200 to 3300m/min, preferably 2500 to 3000m/min, and more preferably 2600 to 2800 m/min.

On the other hand, the invention also provides the application of the high-strength polyamide 56 industrial yarn in the fields of sewing threads, tire cord threads, air bag yarns, demolding cloth, water cloth, canvas, safety belts, ropes, fishing nets, industrial filter cloth, conveying belts, parachutes, tents and bags.

Due to the adoption of the scheme, the invention has the beneficial effects that:

first, the raw material for producing the highly viscous polyamide 56 resin used in the present invention is produced by a biological method, is a green material, does not depend on petroleum resources and does not cause serious pollution to the environment, and can reduce the emission of carbon dioxide and the generation of greenhouse effect.

Secondly, the high-strength polyamide 56 industrial yarn prepared by the invention has better mechanical property and damp-heat resistance.

Thirdly, the preparation method of the high-strength polyamide 56 industrial yarn has good manufacturability and quality stability, the number of times of monofilament interruption and the number of broken filaments are few in the production process, the production efficiency is high, and the production cost is low.

Fourthly, the high-strength polyamide 56 industrial yarn prepared by the method can be prepared by adopting conventional polyamide 6 and polyamide 66 industrial yarn equipment, the spinning equipment is not required to be modified, the yield can be improved, the production cost is reduced and great benefits are brought to spinning enterprises by optimizing the quality of the polyamide 56 resin and the spinning process.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The industrial yarn prepared by optimizing the spinning process, adjusting the spinning temperature and the assembly pressure, increasing the slow cooling device, the cooling process, the oiling device, the pressure of the pre-network and the main network, the drafting process, the sizing process and the winding process has good mechanics, humidity resistance and heat resistance, and the stability of the production quality.

In some preferred embodiments of the invention, the breaking strength of the high-strength polyamide 56 industrial yarn is 8.2-10.0 cN/dtex, preferably 8.4-9.6 cN/dtex, more preferably 8.7-9.2 cN/dtex; and/or the presence of a gas in the gas,

The water bath treatment temperature is 70-110 ℃, the preferable temperature is 75-100 ℃, the more preferable temperature is 80-90 ℃, and the water bath treatment time is 20-60 min, the preferable time is 30-50 min; and/or the humidity adjusting temperature is 18-30 ℃, preferably 20-27 ℃, the humidity adjusting humidity is 60-95%, and the humidity adjusting time is 1-48 h, preferably 4-40 h, and more preferably 8-30 h. Preferably, the conditions of the water bath treatment are as follows: the treatment temperature is 90 ℃, and the treatment time is 30 min; and/or the presence of a gas in the gas,

Preferably, the filament breakage frequency of the high-strength polyamide 56 industrial filament is less than or equal to 4 per 24h, preferably less than or equal to 2 per 24h, and more preferably less than or equal to 1 per 24 h; and/or the presence of a gas in the gas,

In some preferred embodiments of the present invention, the method for preparing the high-strength polyamide 56 industrial yarn comprises the following steps:

In some preferred embodiments of the present invention, the drawing in step (2) is performed by ejecting the melt of the polyamide 56 obtained in step (1) through a spinneret of a spinning beam to obtain the as-spun yarn; and/or the presence of a gas in the gas,

In some preferred embodiments of the invention, the heat preservation in the step (3) is performed by using a slow cooling device, the slow cooling device is a hot jacket which is arranged at the lower part of the spinneret plate and is closely adjacent to the spinneret plate so as to ensure that the nascent fiber is uniformly and slowly cooled, the length and the temperature of the hot jacket are changed along with the specification of the spinneret plate and the fineness of the filament bundle, wherein the slow cooling height refers to the thickness of the hot jacket, and the slow cooling height is 100-350 mm, preferably 200-300 mm; the slow cooling temperature refers to the ambient temperature around the tows, and is 250-320 ℃, preferably 250-300 ℃; and/or the presence of a gas in the gas,

the oiling comprises the mode of oiling by adopting an oil nozzle, an oil tanker or an oil lip, for example, 2 or more oil nozzles, oil tankers or oil lips are adopted for oiling, and 2 oil nozzles are preferably adopted for oiling; and/or the height of the oil nozzle from the spinneret plate is more than or equal to 3m, preferably more than or equal to 3.5m, and more preferably more than or equal to 4 m; and/or the width of the oil nozzle is 8-25 mm, preferably 10-22 mm, and more preferably 12-18 mm; and/or the oiling rate is 0.6-2.0%, preferably 0.8-1.5%, and more preferably 1.0-1.2%.

among them, preferred are: the stretching ratio of the first-stage stretching is 1.0-1.1; and/or the stretching multiple of the second-stage stretching is 3.0-4.0; and/or the stretching multiple of the third stage stretching is 1.3-1.6; and/or the stretching multiple of the fourth stage stretching is 0.9-1.0; and/or the total stretching multiple of the stretching is preferably 4.4-6.0; and/or the temperature of the tension heat setting is 180-230 ℃, preferably 200-220 ℃; and/or the temperature of the relaxation heat setting is 120-200 ℃, preferably 140-180 ℃; and/or the speed retraction of the fourth heat roller pair and the fifth heat roller pair is 50-200 m/min, preferably 100-150 m/min; and/or the presence of a gas in the gas,

the main network pressure is 2.5-4.5 bar, preferably 3.0-3.5 bar; and/or the presence of a gas in the gas,

the winding speed is 2200 to 3300m/min, preferably 2500 to 3000m/min, and more preferably 2600 to 2800 m/min.

In some preferred embodiments of the present invention, the total stretching ratio of the stretching is preferably 4.4 to 5.8, preferably 4.6 to 5.5, and more preferably 4.8 to 5.3.

In the following examples of the present invention, the high-viscosity polyamide 56 resin is obtained by slicing a low-viscosity polyamide 56 resin to solid-phase tackify the resin, i.e., drying the resin at a high temperature while removing water, and continuing the polycondensation reaction to obtain a high-viscosity polyamide 56 resin, for example, drying the low-viscosity polyamide 56 resin at a high temperature to increase the viscosity of the resin to obtain a high-viscosity polyamide 56 resin. Preferably, the temperature of the solid-phase tackifying is 150-200 ℃, and preferably 160-180 ℃; and/or the drying time of the solid-phase tackifying is 10-50 h, preferably 15-30 h.

The low viscosity polyamide 56 resin may be prepared according to conventional methods, for example, as disclosed in reference to CN108503826A or CN 108503824A.

The high-viscosity polyamide 56 resin is characterized in that the relative viscosity of 96% sulfuric acid is 3.3-4.0, and the water content is 300-550 ppm.

In the present invention, unless otherwise specified, the detection method of each parameter is as follows:

(1) breaking strength: the tensile property of the chemical fiber filaments is measured according to the national standard GB/T14344-2008 test method for the tensile property of the chemical fiber filaments.

(2) Elongation at break: the tensile property of the chemical fiber filaments is measured according to the national standard GB/T14344-2008 test method for the tensile property of the chemical fiber filaments.

(3) Broken filaments (number of times/24 h): and (5) manual statistics.

(4) The number of broken filaments: measured by a hairiness on-line detector during winding.

(5) Water bath treatment: taking a section of high-strength polyamide 56 industrial yarn, pre-tensioning the high-strength polyamide 56 industrial yarn by 0.05 +/-0.005 cN/dtex, marking the middle two ends of the high-strength polyamide 56 industrial yarn by 50.00cm, wrapping the high-strength polyamide 56 industrial yarn with gauze, putting the high-strength polyamide 56 industrial yarn into a water bath at 90 ℃ for boiling for 30min, drying a sample, and calculating by adopting the following formula:

humidifying industrial yarn: according to GB/T6529-2008, the high-strength polyamide 56 industrial yarn package is placed in a constant-temperature and constant-humidity room, the temperature is 20 ℃, the relative humidity is 65%, and the time is 24 hours.

The retention ratio of breaking strength after water bath treatment (breaking strength after water bath treatment/breaking strength before water bath treatment) × 100%.

The retention ratio of the breaking strength after the moisture control treatment of the industrial yarn (breaking strength after the moisture control treatment of the industrial yarn/breaking strength before the moisture control treatment of the industrial yarn) × 100%.

The breaking strength is measured according to the national standard GB/T14344-.

(6) The fluctuation of the elongation at break after the water bath treatment is the elongation at break before the water bath treatment-the elongation at break after the water bath treatment; and (3) the elongation at break fluctuation after the industrial yarn humidity conditioning treatment is equal to the elongation at break before the industrial yarn humidity conditioning treatment-the elongation at break after the industrial yarn humidity conditioning treatment. The elongation at break is determined according to the national standard GB/T14344-.

(7) High viscosity polyamide 56 resin relative viscosity: the relative viscosity of the polyamide 56 resin was measured by the concentrated sulfuric acid method with an Ubbelohde viscometer, which comprises the following steps: 0.25. + -. 0.0002g of dried polyamide 56 resin was weighed out accurately, dissolved in 50mL of concentrated sulfuric acid (96%), and the flow time t of the concentrated sulfuric acid was measured and recorded in a thermostatic water bath at 25 ℃₀And a flow time t of the polyamide 56 resin solution.

The relative viscosity is calculated by the formula: relative viscosity VN ═ t/t₀(ii) a t-solution flow time; t is t₀-solvent flow time.

(8) Water content of highly viscous polyamide 56 resin: measured according to Karl Fischer water titration.

(9) Dynamic viscosity of oil agent: according to the national standard GB/T265-1988 petroleum product kinematic viscosity determination method and kinetic viscosity calculation method.

The slow cooling device used in the following examples or comparative examples is a thermal jacket located immediately below the spinneret to ensure uniform and slow cooling of the as-spun filaments, and the length and temperature of the thermal jacket vary with the specifications of the spinneret and the fineness of the filament bundle, wherein the slow cooling height is the thickness of the thermal jacket and the slow cooling temperature is the ambient temperature around the filament bundle.

Preparation example

Referring to CN108503824A, example 3 prepares low-viscosity polyamide 56 resin, and then prepares high-viscosity polyamide 56 resin by solid-phase tackifying the low-viscosity polyamide 56 resin. The temperature of the solid phase tackifying is 160 ℃, and the drying time is 20 h.

The relative viscosity of 96% sulfuric acid of the low-viscosity polyamide 56 resin is 2.4. The high-viscosity polyamide 56 resin has a relative viscosity of 3.4 in 96% sulfuric acid and a water content of 500 ppm.

According to the method described in the preparation example, a highly viscous polyamide 56 resin having a relative viscosity of 96% sulfuric acid of 3.3 to 4.0 and a water content of 300 to 550ppm can be prepared.

Example one (high strength polyamide 56 industrial yarn preparation):

the preparation method comprises the following steps:

(3) and (3) carrying out heat preservation, cooling, oiling, pre-networking, multi-stage stretching, tension sizing, relaxation sizing, main networking and winding on the primary yarn prepared in the step (2) to obtain the polyamide 56 industrial yarn.

The relative viscosity of the high-viscosity polyamide 56 resin 96% sulfuric acid in the step (1) is 3.4, and the water content is 500 ppm.

In the step (2), the step of drawing is to spray the melt of the polyamide 56 prepared in the step (1) through a spinneret plate of a spinning manifold to prepare the nascent fiber; the temperature of the spinning manifold is 285 ℃; the pressure of a spinning assembly of the spinning manifold is 18 MPa.

In the step (3), the heat preservation adopts a slow cooling device, the slow cooling height is 300mm, and the slow cooling temperature is 300 ℃.

The cooling is carried out by cross air blowing, the wind speed is 0.7m/s, the wind temperature is 22 ℃, and the wind humidity is 80%.

The method comprises the following steps that TC1355 oil with the oil concentration of 10 wt% is adopted during oiling, the dynamic viscosity of the oil is less than or equal to 200mPas, the water content is 90 wt%, the oiling is carried out by adopting a nozzle oiling mode and 2 nozzles, and the distance between the nozzles and a spinneret plate is 3 m; the width of each oil nozzle 2 is 15 mm; the oiling rate is 1.0%. The pre-network pressure was 2.0 bar.

The stretching process adopts 5 pairs of hot rollers and is divided into four stages of stretching, and the stretching process comprises the following steps: feeding oiled nascent yarn to a first pair of hot rollers, performing primary pre-stretching between the first pair of hot rollers and a second pair of hot rollers, performing secondary main stretching between the second pair of hot rollers and a third pair of hot rollers, performing tertiary main stretching between the third pair of hot rollers and a fourth pair of hot rollers and performing tension heat setting, and performing fourth-stage secondary stretching between the fourth pair of hot rollers and a fifth pair of hot rollers and performing relaxation heat setting; wherein the first stage stretch has a stretch ratio of 1.05; the stretching ratio of the second-stage stretching is 3.6; the stretching ratio of the third stage stretching is 1.5; the stretching ratio of the fourth stage stretching is 0.95; the total draw ratio of the draw was 5.38; the temperature of the tension heat setting is 220 ℃; the temperature of the relaxation heat setting is 160 ℃; the retraction of the speed of the fourth heat roller pair and the fifth heat roller pair is 100 m/min; the main network pressure was 3.0 bar. The winding speed was 2800 m/min.

The obtained high-strength polyamide 56 industrial yarn was subjected to performance tests such as breaking strength, elongation at break, filament breakage, water bath treatment, industrial yarn moisture control treatment and the like, and the results are shown in table 1.

Example two (high strength polyamide 56 industrial yarn preparation):

In the step (1), the relative viscosity of the high-viscosity polyamide 56 resin with 96% sulfuric acid is 3.5, and the water content is 400 ppm.

In the step (2), the step of drawing is to spray the melt of the polyamide 56 prepared in the step (1) through a spinneret plate of a spinning manifold to prepare the nascent fiber; the temperature of the spinning manifold is 288 ℃; the pressure of a spinning assembly of the spinning manifold is 16 MPa.

In the step (3), the heat preservation adopts a slow cooling device, the slow cooling height is 200mm, and the slow cooling temperature is 270 ℃.

The cooling is performed by cross-air blowing, the air speed is 0.8m/s, the air temperature is 21 ℃, and the air humidity is 85%.

The method comprises the following steps that TC14686 oil agent with the oil agent concentration of 15 wt% is adopted during oiling, the dynamic viscosity of the oil agent is less than or equal to 200mPas, the water content is 85 wt%, the oiling is carried out by adopting an oil nozzle oiling mode and 2 oil nozzles, and the distance between the oil nozzles and a spinneret plate is 2.8 m; the width of each of the 2 oil nozzles is 12 mm; the oiling rate is 1.05%. The pre-network pressure was 1.5 bar.

The stretching process adopts 5 pairs of hot rollers and is divided into four stages of stretching, and the stretching process comprises the following steps: feeding oiled nascent yarn to a first pair of hot rollers, performing primary pre-stretching between the first pair of hot rollers and a second pair of hot rollers, performing secondary main stretching between the second pair of hot rollers and a third pair of hot rollers, performing tertiary main stretching between the third pair of hot rollers and a fourth pair of hot rollers and performing tension heat setting, and performing fourth-stage secondary stretching between the fourth pair of hot rollers and a fifth pair of hot rollers and performing relaxation heat setting; wherein the first stage stretch has a stretch multiple of 1.03; the stretching ratio of the second-stage stretching is 3.5; the stretching ratio of the third stage stretching is 1.6; the stretching ratio of the fourth stage stretching is 0.92; the total draw ratio of the draw is 5.3; the temperature of the tension heat setting is 210 ℃; the temperature of the relaxation heat setting is 150 ℃; the retraction speed of the fourth heat roller pair and the fifth heat roller pair is 120 m/min; the main network pressure was 3.3 bar. The winding speed was 3000 m/min.

Example three (high strength polyamide 56 industrial yarn preparation):

the preparation method comprises the following steps:

The relative viscosity of the high-viscosity polyamide 56 resin 96% sulfuric acid in the step (1) is 3.7, and the water content is 450 ppm.

In the step (2), the step of drawing is to spray the melt of the polyamide 56 prepared in the step (1) through a spinneret plate of a spinning manifold to prepare the nascent fiber; the temperature of the spinning manifold is 283 ℃; the pressure of a spinning assembly of the spinning manifold is 14 MPa.

In the step (3), a slow cooling device is adopted for heat preservation, the slow cooling height is 250mm, and the slow cooling temperature is 280 ℃.

The cooling is carried out by cross air blowing, the wind speed is 0.6m/s, the wind temperature is 20 ℃, and the wind humidity is 75%.

The method comprises the following steps of applying oil by using a TCP-60 oil agent with the oil agent concentration of 20 wt%, wherein the dynamic viscosity of the oil agent is less than or equal to 200mPas, the water content is 80 wt%, the oil is applied by using an oil nozzle applying mode and applying oil by using 2 oil nozzles, and the distance between the oil nozzles and a spinneret plate is 3.2 m; the width of each oil nozzle 2 is 15 mm; the oiling rate is 1.1%. The pre-network pressure was 1.8 bar.

The stretching process adopts 5 pairs of hot rollers and is divided into four stages of stretching, and the stretching process comprises the following steps: feeding oiled nascent yarn to a first pair of hot rollers, performing primary pre-stretching between the first pair of hot rollers and a second pair of hot rollers, performing secondary main stretching between the second pair of hot rollers and a third pair of hot rollers, performing tertiary main stretching between the third pair of hot rollers and a fourth pair of hot rollers and performing tension heat setting, and performing fourth-stage secondary stretching between the fourth pair of hot rollers and a fifth pair of hot rollers and performing relaxation heat setting; wherein the first stage stretch has a stretch ratio of 1.05; the stretching ratio of the second-stage stretching is 3.7; the stretching ratio of the third stage stretching is 1.5; the stretching ratio of the fourth stage stretching is 0.95; the total draw ratio of the draw was 5.54; the temperature of the tension heat setting is 215 ℃; the temperature of the relaxation heat setting is 160 ℃; the retraction of the speed of the fourth heat roller pair and the fifth heat roller pair is 150 m/min; the main network pressure was 3.5 bar. The winding speed was 2500 m/min.

Example four (high strength polyamide 56 industrial yarn preparation):

the preparation method comprises the following steps:

The relative viscosity of the high-viscosity polyamide 56 resin 96% sulfuric acid in the step (1) is 3.3, and the water content is 400 ppm.

In the step (2), the step of drawing is to spray the melt of the polyamide 56 prepared in the step (1) through a spinneret plate of a spinning manifold to prepare the nascent fiber; the temperature of the spinning box body is 286 ℃; the pressure of a spinning assembly of the spinning manifold is 17 MPa.

In the step (3), the heat preservation adopts a slow cooling device, the slow cooling height is 230mm, and the slow cooling temperature is 250 ℃.

The cooling is carried out by cross air blowing, the wind speed is 0.9m/s, the wind temperature is 22 ℃, and the wind humidity is 70%.

The method comprises the following steps of applying oil by using a TCP-80 oil agent with the oil agent concentration of 18 wt%, wherein the dynamic viscosity of the oil agent is less than or equal to 200mPas, the water content is 82 wt%, the oil is applied by using an oil nozzle applying mode and 2 oil nozzles, and the distance between the oil nozzles and a spinneret plate is 3.5 m; the width of each of the 2 oil nozzles is 12 mm; the oiling rate is 1.08%. The pre-network pressure was 1.9 bar.

The stretching process adopts 5 pairs of hot rollers and is divided into four stages of stretching, and the stretching process comprises the following steps: feeding oiled nascent yarn to a first pair of hot rollers, performing primary pre-stretching between the first pair of hot rollers and a second pair of hot rollers, performing secondary main stretching between the second pair of hot rollers and a third pair of hot rollers, performing tertiary main stretching between the third pair of hot rollers and a fourth pair of hot rollers and performing tension heat setting, and performing fourth-stage secondary stretching between the fourth pair of hot rollers and a fifth pair of hot rollers and performing relaxation heat setting; wherein the first stage stretch has a stretch multiple of 1.03; the stretching ratio of the second-stage stretching is 3.8; the stretching ratio of the third stage stretching is 1.6; the stretching ratio of the fourth stage stretching is 0.93; the total draw ratio of the draw was 5.82; the temperature of the tension heat setting is 225 ℃; the temperature of the relaxation heat setting is 170 ℃; the retraction speed of the fourth heat roller pair and the fifth heat roller pair is 120 m/min; the main network pressure was 3.4 bar. The winding speed was 2700 m/min.

Example five (high strength polyamide 56 industrial yarn preparation):

the preparation method comprises the following steps:

The relative viscosity of the high-viscosity polyamide 56 resin 96% sulfuric acid in the step (1) is 3.8, and the water content is 550 ppm.

In the step (2), the step of drawing is to spray the melt of the polyamide 56 prepared in the step (1) through a spinneret plate of a spinning manifold to prepare the nascent fiber; the temperature of the spinning manifold is 289 ℃; the pressure of a spinning assembly of the spinning manifold is 20 MPa.

In the step (3), the heat preservation adopts a slow cooling device, the slow cooling height is 280mm, and the slow cooling temperature is 300 ℃.

The cooling is carried out by cross air blowing, the wind speed is 0.8m/s, the wind temperature is 19 ℃, and the wind humidity is 80%.

The method comprises the following steps of applying oil by using N-353 oil with the oil concentration of 10 wt%, wherein the dynamic viscosity of the oil is less than or equal to 200mPas, the water content is 90 wt%, applying oil by using an oil nozzle applying mode and applying oil by using 2 oil nozzles, and the distance between the oil nozzles and a spinneret plate is 3.0 m; the width of each of the 2 oil nozzles is 12 mm; the oiling rate is 1.1%. The pre-network pressure was 2.0 bar.

The stretching process adopts 5 pairs of hot rollers and is divided into four stages of stretching, and the stretching process comprises the following steps: feeding oiled nascent yarn to a first pair of hot rollers, performing primary pre-stretching between the first pair of hot rollers and a second pair of hot rollers, performing secondary main stretching between the second pair of hot rollers and a third pair of hot rollers, performing tertiary main stretching between the third pair of hot rollers and a fourth pair of hot rollers and performing tension heat setting, and performing fourth-stage secondary stretching between the fourth pair of hot rollers and a fifth pair of hot rollers and performing relaxation heat setting; wherein the first stage stretch has a stretch ratio of 1.05; the stretching ratio of the second-stage stretching is 3.8; the stretching ratio of the third stage stretching is 1.5; the stretching ratio of the fourth stage stretching is 0.95; the total draw ratio of the draw was 5.68; the temperature of the tension heat setting is 205 ℃; the temperature of the relaxation heat setting is 150 ℃; the retraction of the speed of the fourth heat roller pair and the fifth heat roller pair is 100 m/min; the main network pressure was 3.5 bar. The winding speed was 2900 m/min.

EXAMPLE six

The experiment was carried out according to the starting material and the preparation method of example four, with the only difference that oiling in step (3) was carried out with an oiling agent TC1355 with an oiling agent concentration of 100 wt%, and a kinematic viscosity of 200mPas or less; the oiling is carried out in an oil nozzle oiling mode, 2 oil nozzles are used for oiling, and the distance between each oil nozzle and a spinneret plate is 3 m; the width of each oil nozzle 2 is 15 mm; the oiling rate is 1.0%.

EXAMPLE seven

The experiment is carried out according to the raw materials and the preparation method of the example four, and the difference is only that the oiling in the step (3) adopts the oiling agent TC-14686 with the oiling agent concentration of 100 weight percent and the dynamic viscosity of less than or equal to 200 mPas; the oiling is carried out in an oil nozzle oiling mode, 2 oil nozzles are used for oiling, and the distance between each oil nozzle and a spinneret plate is 3.5 m; the width of the oil nozzle is 12 mm; the oiling rate is 1.2%.

Comparative example one (high strength polyamide 56 industrial yarn preparation):

the experiment was carried out according to the starting material and preparation method of example one, with the difference that the temperature of the spinning beam was 310 ℃.

Comparative example two (high-strength polyamide 56 industrial yarn preparation):

the experiment was carried out according to the starting material and preparation method of example one, with the difference that the pressure of the spinning pack was 8 MPa.

Comparative example three (high strength polyamide 56 industrial yarn preparation):

tests were carried out with the starting materials and preparation method of example two, with the exception that no slow cooling device was used.

Comparative example four (high strength polyamide 56 industrial yarn preparation):

tests were conducted according to the materials and preparation methods of example two, except that the slow cooling temperature was 100 deg.C

Comparative example five (high strength polyamide 56 industrial yarn preparation):

the experiment was carried out with the starting materials and preparation method of example three, with the difference that the wind speed was 1.5 m/s.

Comparative example six (high strength polyamide 56 industrial yarn preparation):

the experiment was carried out according to the starting materials and preparation method of example three, with the difference that the blast temperature was 30 ℃.

Comparative example seven (high strength polyamide 56 industrial yarn preparation):

tests were carried out according to the starting materials and preparation methods of example three, with the difference that the moisture was 40%.

Comparative example eight (high strength polyamide 56 industrial yarn preparation):

tests were carried out with the starting materials and preparation method according to example four, with the difference that the pre-network pressure was 0.6 bar; and the dynamic viscosity of the oiling agent is more than 300mPas, and the oiling agent is TC 1152.

Comparative example no (high strength polyamide 56 industrial yarn preparation):

tests were conducted according to the raw materials and preparation methods of example four, except that the total draw ratio of the draw was 4.0;

oiling in the step (3) by adopting oiling agent TC1355 with the oiling agent concentration of 100 wt%, wherein the dynamic viscosity is less than or equal to 200 mPas; the oiling is carried out in an oil nozzle oiling mode, 2 oil nozzles are used for oiling, and the distance between each oil nozzle and a spinneret plate is 3 m; the width of each oil nozzle 2 is 15 mm; the oiling rate is 1.0%.

Comparative example ten (high strength polyamide 56 industrial yarn preparation):

the tests were carried out according to the starting materials and the preparation method of example five, with the difference that the temperature for the intense heat-setting was 140 ℃.

Comparative example eleven (high strength polyamide 56 industrial yarn preparation):

the experiment was carried out according to the starting materials and preparation method of example five, except that the temperature for relaxation heat setting was 80 ℃.

Comparative example twelve (high strength polyamide 56 industrial yarn preparation):

a test was conducted in accordance with the feedstock and production method of example one except that the fourth heat roll pair was retracted from the fifth heat roll pair by an amount of 0 m/min.

Comparative example thirteen (high-strength polyamide 56 industrial yarn preparation):

experiments were conducted following the starting materials and preparation method of example one, except that the main network pressure was 1.0 bar.

Comparative example fourteen (high strength polyamide 56 industrial yarn preparation):

the experiment was carried out according to the starting material and the preparation method of example one, with the difference that the winding speed was 1500 m/min.

TABLE 1 high-Strength Polyamide 56 Industrial yarn Performance index

As can be seen from the measured data in Table 1, the high-strength polyamide 56 industrial yarns of the first to seventh embodiments have good mechanical property and damp-heat resistance, the breaking strength is 8.8 to 9.3cN/dtex, the breaking strength retention rate after water bath treatment is 90.8 to 95.4 percent, and the elongation at break fluctuation is 2.0 to 5.3 percent; the retention rate of the breaking strength of the industrial yarn after humidity conditioning treatment is 93.5-97.0%, and the fluctuation of the elongation at break is 0.3-1.3%. In the first to the fourteenth comparative examples, proper slow cooling, stretching and oiling methods are not selected, which bring adverse effects on the mechanical properties and the humidity resistance of the prepared high-strength polyamide 56 industrial yarn, so that the breaking strength is greatly reduced to 6.0-7.1 cN/dtex, the breaking strength retention rate is reduced to 72.0-82.2% after water bath treatment, and the elongation at break fluctuation is increased to 14.8-19.0%; the retention rate of the breaking strength of the industrial yarn after humidity conditioning treatment is reduced to 80.0-83.3%, and the fluctuation of the elongation at break is increased to 5.1-8.7%.

On the other hand, the manufacturing method provided by the invention has good manufacturability and quality stability, the broken filaments of the high-strength polyamide 56 industrial yarns in the first to seventh embodiments are only 1-2 times/24 h, and the broken filaments are only 1-3 per 10kg of package; compared with the first to the fourteen high-strength polyamide 56 industrial yarns, broken filaments of the industrial yarns greatly rise to 16-28 times/24 hours, broken filaments of the industrial yarns greatly rise to 165-222/10 kg packages, the production efficiency and the yield are seriously affected, and the production cost is increased.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, 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 embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.

Claims

1. A preparation method of high-strength polyamide 56 industrial yarn is characterized by comprising the following steps: the preparation method comprises the following steps:

(3) carrying out heat preservation, cooling, oiling, pre-networking, multi-stage stretching, tension sizing, relaxation sizing, main networking and winding on the primary yarn prepared in the step (2) to obtain the polyamide 56 industrial yarn;

the concentration of the oiling agent used in the oiling process in the step (3) is 65-100 wt%, and the dynamic viscosity of the oiling agent is less than or equal to 300 mPas;

the pre-network pressure in the step (3) is 1-2.5 bar;

and (3) the main network pressure is 2.5-4.5 bar.

2. The method for preparing high-strength polyamide 56 industrial yarn according to claim 1, wherein: the relative viscosity of 96% sulfuric acid of the high-viscosity polyamide 56 resin in the step (1) is 3.3-4.0; and/or the presence of a gas in the gas,

the water content of the high-viscosity polyamide 56 resin is 300-550 ppm.

3. The method for preparing high-strength polyamide 56 industrial yarn as claimed in claim 2, wherein: in the step (1), the relative viscosity of 96% sulfuric acid of the high-viscosity polyamide 56 resin is 3.4-3.8, and the water content of the high-viscosity polyamide 56 resin is 350-500 ppm.

4. The method for preparing high-strength polyamide 56 industrial yarn as claimed in claim 2, wherein: in the step (1), the relative viscosity of 96% sulfuric acid of the high-viscosity polyamide 56 resin is 3.5-3.6, and the water content of the high-viscosity polyamide 56 resin is 350-500 ppm.

5. The method for preparing high-strength polyamide 56 industrial yarn according to claim 1, wherein: in the step (2), the drawing is to spray the polyamide 56 melt through a spinneret plate of a spinning manifold to form the primary yarn; and/or the presence of a gas in the gas,

the temperature of the spinning box body is 280-295 ℃; and/or the presence of a gas in the gas,

the pressure of a spinning assembly of the spinning manifold is 13-25 MPa.

6. The method for preparing high-strength polyamide 56 industrial yarn according to claim 5, wherein: the temperature of the spinning manifold in the step (2) is 283-293 ℃; and/or the pressure of a spinning assembly of the spinning manifold is 15-20 MPa.

7. The method for preparing high-strength polyamide 56 industrial yarn according to claim 5, wherein: the temperature of the spinning manifold in the step (2) is 285-290 ℃; and/or the pressure of a spinning assembly of the spinning manifold is 17-18 MPa.

8. The method for preparing high-strength polyamide 56 industrial yarn according to claim 1, wherein: in the step (3), the heat preservation adopts a slow cooling device, the slow cooling device is a hot jacket which is arranged at the lower part of the spinneret plate and is closely adjacent to the spinneret plate, the slow cooling height refers to the thickness of the hot jacket, and the slow cooling height is 100-350 mm; the slow cooling temperature refers to the ambient temperature around the filament bundle, and is 250-320 ℃.

9. The method for preparing high-strength polyamide 56 industrial yarn according to claim 8, wherein: the slow cooling height is 200-300 mm; the slow cooling temperature is 250-300 ℃.

10. The method for preparing high-strength polyamide 56 industrial yarn according to claim 1, wherein: in the step (3), the cooling is air cooling by cross air blowing or circular air blowing, and the air cooling speed is 0.4-0.9 m/s; the air temperature of the air cooling is 16-25 ℃; the air-cooled air humidity is 60-90%.

11. The process for preparing high-strength polyamide 56 industrial yarn as claimed in claim 10, wherein: the air cooling wind speed is 0.6-0.8 m/s; the air temperature of the air cooling is 18-22 ℃; the air-cooled air humidity is 75-85%.

12. The method for preparing high-strength polyamide 56 industrial yarn according to claim 1, wherein: the concentration of the oiling agent used in oiling is 65-100 wt%, and the dynamic viscosity of the oiling agent is less than or equal to 200 mPas; the oiling comprises the step of oiling by adopting an oil nozzle, an oil tanker or an oil lip, and the step of oiling by adopting 2 or more oil nozzles, oil tankers or oil lips; and/or the height of the oil nozzle from the spinneret plate is more than or equal to 3 m; and/or the width of the oil nozzle is 8-25 mm; and/or the oiling rate is 0.6-2.0%.

13. The process for preparing high-strength polyamide 56 industrial yarn as claimed in claim 12, wherein: the height of the oil nozzle from the spinneret plate is more than or equal to 3.5 m; and/or the width of the oil nozzle is 10-22 mm.

14. The process for preparing high-strength polyamide 56 industrial yarn as claimed in claim 12, wherein: the oiling rate is 0.8-1.5%.

15. The method for preparing high-strength polyamide 56 industrial yarn according to claim 1, wherein: the pre-network pressure is 1.5-2.0 bar.

16. The method for preparing high-strength polyamide 56 industrial yarn according to claim 1, wherein:

the stretching process adopts 5 pairs of hot rollers and is divided into four stages of stretching, and the stretching process comprises the following steps: feeding oiled nascent yarn to a first pair of hot rollers, performing primary pre-stretching between the first pair of hot rollers and a second pair of hot rollers, performing secondary main stretching between the second pair of hot rollers and a third pair of hot rollers, performing tertiary main stretching between the third pair of hot rollers and a fourth pair of hot rollers and performing tension setting, and performing fourth-stage secondary stretching between the fourth pair of hot rollers and a fifth pair of hot rollers and performing relaxation setting;

wherein the total stretching multiple of the stretching is 4.5-6.0.

17. The process for preparing high strength polyamide 56 industrial yarn of claim 16, wherein: the stretching multiple of the first-stage pre-stretching is 1.0-1.1; and/or the stretching multiple of the second-stage main stretching is 3.0-4.0; and/or the stretching multiple of the third-stage main stretching is 1.3-1.6; and/or the stretching multiple of the fourth-stage stretching is 0.9-1.0.

18. The method for preparing high-strength polyamide 56 industrial yarn according to claim 1, wherein: the temperature for tension setting is 180-230 ℃, and the temperature for relaxation setting is 120-200 ℃.

19. The method for preparing high-strength polyamide 56 industrial yarn according to claim 1, wherein: the temperature of the tension setting is 200-220 ℃, and the temperature of the relaxation setting is 140-180 ℃.

20. The process for preparing high strength polyamide 56 industrial yarn of claim 16, wherein: the speed retraction of the fourth heat roller pair and the fifth heat roller pair is 50-200 m/min.

21. The process for preparing high strength polyamide 56 industrial yarn of claim 16, wherein: the speed retraction of the fourth heat roller pair and the fifth heat roller pair is 100-150 m/min.

22. The method for preparing high-strength polyamide 56 industrial yarn according to claim 1, wherein: the main network pressure is 3.0-3.5 bar.

23. The method for preparing high-strength polyamide 56 industrial yarn according to claim 1, wherein: the winding speed is 2200-3300 m/min.

24. The method for preparing high-strength polyamide 56 industrial yarn according to claim 1, wherein: the winding speed is 2500-3000 m/min.

25. The method for preparing high-strength polyamide 56 industrial yarn according to claim 1, wherein: the winding speed is 2600-2800 m/min.

26. The method of claim 1, wherein: the breaking strength of the high-strength polyamide 56 industrial yarn is 8.2-10.0 cN/dtex; after water bath treatment, the breaking strength retention rate of the high-strength polyamide 56 industrial yarn is more than or equal to 88 percent; after the industrial yarn is subjected to humidity conditioning treatment, the breaking strength retention rate of the high-strength polyamide 56 industrial yarn is more than or equal to 90 percent;

the elongation at break of the high-strength polyamide 56 industrial yarn is 16-24%; after water bath treatment, the breaking elongation of the high-strength polyamide 56 industrial yarn is less than or equal to 33 percent; the elongation fluctuation is less than or equal to 10 percent; after the industrial yarn is subjected to humidity adjustment treatment, the breaking elongation of the high-strength polyamide 56 industrial yarn is less than or equal to 27%; the elongation fluctuation is less than or equal to 3 percent;

the water bath treatment temperature is 80-90 ℃, and the water bath treatment time is 20-60 min;

the humidity adjusting temperature is 20-27 ℃, the humidity adjusting humidity is 60-95%, and the humidity adjusting time is 8-30 h.

27. A high-strength polyamide 56 industrial yarn obtained by the production method according to any one of claims 1 to 26, characterized in that: the breaking strength of the high-strength polyamide 56 industrial yarn is 8.2-10.0 cN/dtex, and after water bath treatment, the breaking strength retention rate of the high-strength polyamide 56 industrial yarn is more than or equal to 92%; after the industrial yarn is subjected to humidity conditioning treatment, the breaking strength retention rate of the high-strength polyamide 56 industrial yarn is more than or equal to 93 percent; the water bath treatment temperature is 80-90 ℃, and the water bath treatment time is 20-60 min; the humidity adjusting temperature is 20-27 ℃, the humidity adjusting humidity is 60-95%, and the humidity adjusting time is 8-30 h.

28. A high-strength polyamide 56 industrial yarn obtained by the production method according to any one of claims 1 to 26, characterized in that: the elongation at break of the high-strength polyamide 56 industrial yarn is 16-24%, and after water bath treatment, the elongation at break of the high-strength polyamide 56 industrial yarn is less than or equal to 33%, and the elongation fluctuation is less than or equal to 6%; after the industrial yarn is subjected to humidity adjustment treatment, the elongation at break of the high-strength polyamide 56 industrial yarn is less than or equal to 27%, and the elongation fluctuation is less than or equal to 3%; the water bath treatment temperature is 80-90 ℃, and the water bath treatment time is 20-60 min; the humidity adjusting temperature is 20-27 ℃, the humidity adjusting humidity is 60-95%, and the humidity adjusting time is 8-30 h.

29. The high tenacity polyamide 56 industrial yarn of claim 27 or 28, wherein: the monofilament breaking frequency of the high-strength polyamide 56 industrial yarn is less than or equal to 2 per 24 hours; and/or the presence of a gas in the gas,

the broken filaments of the high-strength polyamide 56 industrial filaments are not more than 4/10 kg of package.

30. Use of the high tenacity polyamide 56 industrial yarn of any one of claims 27 to 29 in sewing thread, tire cord, air bag yarn, release fabric, tarpaulin, canvas, safety belts, ropes, fishing nets, industrial filter cloth, conveyor belts, parachutes, tents, bags and suitcases.