阅读说明：本技术 一种聚酰胺5x中强丝及其制备方法 (Polyamide 5X medium-strength yarn and preparation method thereof ) 是由 孙朝续 徐晓辰 秦兵兵 刘修才 于 2017-02-24 设计创作，主要内容包括：本发明提供了一种聚酰胺5X中强丝及其制备方法,聚酰胺5X中强丝的生产原料至少包括1,5-戊二胺和二元羧酸；或者,以1,5-戊二胺和二元羧酸为单体聚合得到的聚酰胺5X；所述聚酰胺5X中强丝的断裂强度为6.0-8.0cN/dtex。制备方法包括以下步骤：(1)、将1,5-戊二胺和二元羧酸聚合,形成聚酰胺5X熔体；或者,将聚酰胺5X树脂加热至熔融状态,形成聚酰胺5X熔体；(2)、将所述聚酰胺5X熔体进行纺丝,形成初生丝；(3)、对所述初生丝进行处理后得到所述聚酰胺5X中强丝。本发明的聚酰胺5X中强丝具有高强度、低伸长率和低热收缩性能等特点；另外,其还具有耐磨性能好、耐碱性能好和尺寸稳定性等优点,从而使得其广泛应用于缝纫线、安全带、绳索、渔网或过滤布等领域。(The invention provides a polyamide 5X medium-strength yarn and a preparation method thereof, wherein the raw materials for producing the polyamide 5X medium-strength yarn at least comprise 1, 5-pentanediamine and dicarboxylic acid; or polyamide 5X obtained by polymerizing 1, 5-pentanediamine and dicarboxylic acid serving as monomers; the breaking strength of the polyamide 5X medium-strength filaments is 6.0-8.0 cN/dtex. The preparation method comprises the following steps: (1) polymerizing 1, 5-pentanediamine and dicarboxylic acid to form a polyamide 5X melt; alternatively, the polyamide 5X resin is heated to a molten state to form a polyamide 5X melt; (2) spinning the polyamide 5X melt to form primary yarn; (3) and processing the primary raw silk to obtain the polyamide 5X medium-strength silk. The polyamide 5X medium-strength yarn has the characteristics of high strength, low elongation, low thermal shrinkage and the like; in addition, the wear-resistant and alkali-resistant composite material also has the advantages of good wear resistance, good alkali resistance, dimensional stability and the like, so that the material can be widely applied to the fields of sewing threads, safety belts, ropes, fishing nets, filter cloth and the like.)

1. A polyamide 5X medium-strength yarn is characterized in that: raw materials for producing the polyamide 5X medium-strength yarn at least comprise 1, 5-pentanediamine and dicarboxylic acid; or polyamide 5X obtained by polymerizing 1, 5-pentanediamine and dicarboxylic acid serving as monomers; the breaking strength of the polyamide 5X medium-strength filaments is 6.0-8.0 cN/dtex; the dry heat shrinkage rate of the polyamide 5X medium-strength yarn is 3.0-8.0%.

2. The polyamide 5X medium strength yarn of claim 1, wherein:

the titer of the polyamide 5X medium-strength fiber is 110-1100dtex, preferably 220-990dtex, more preferably 220-880dtex, and still more preferably 220-550 dtex; and/or the presence of a gas in the gas,

the breaking strength of the strong yarn in the polyamide 5X is preferably 6.3-7.6cN/dtex, more preferably 6.5-7.2cN/dtex, and still more preferably 6.7-7.0 cN/dtex.

3. The polyamide 5X medium strength yarn of claim 1, wherein: the elongation at break of the strong filaments in the polyamide 5X is 14-25%, preferably 14-16%; and/or the presence of a gas in the gas,

the dry heat shrinkage rate of the polyamide 5X medium-strength filament is 3.5-7.5%, and the preferable range is 4.0-6.0%; and/or the presence of a gas in the gas,

the boiling water shrinkage of the polyamide 5X medium-strength filament is 2.0-7.0%, preferably 3.0-6.0%, and more preferably 4.0-5.0%; and/or the presence of a gas in the gas,

the crystallinity of the filament in the polyamide 5X is 60 to 70%, preferably 61 to 69%, more preferably 62 to 68%, and still more preferably 64 to 67%; and/or the presence of a gas in the gas,

the degree of orientation of the filaments in the polyamide 5X is 70 to 80%, preferably 71 to 79%, more preferably 72 to 77%, and still more preferably 73 to 76%.

4. The polyamide 5X medium strength yarn of claim 1, wherein: the 1, 5-pentanediamine is prepared from bio-based raw materials by a fermentation method or an enzyme conversion method; and/or the presence of a gas in the gas,

the number of carbon atoms of the dicarboxylic acid is 4-18; the dicarboxylic acid comprises one or more of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, maleic acid and delta 9-1, 18-octadecenedioic acid; and/or the presence of a gas in the gas,

the raw materials for producing the polyamide 5X medium-strength yarn also contain a comonomer and/or an additive; and/or the presence of a gas in the gas,

preferably, the comonomers comprise: any one or more of aliphatic dicarboxylic acid, alicyclic dicarboxylic acid, aromatic dicarboxylic acid, ethylenediamine, hexamethylenediamine, cyclohexanediamine, xylylenediamine, 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, p-aminomethylbenzoic acid, epsilon-caprolactam and omega-laurolactam;

preferably, the additive comprises: any one or more of a delustering agent, a flame retardant, an antioxidant, an ultraviolet absorbent, an infrared absorbent, a crystallization nucleating agent, a fluorescent brightener and an antistatic agent;

preferably, the additive is added in an amount of 0.001-10% by weight based on the total weight of the raw materials for production.

5. A process for the preparation of a polyamide 5X medium filament according to any one of claims 1 to 4, characterized in that: the preparation method comprises the following steps:

(1) polymerizing 1, 5-pentanediamine and dicarboxylic acid to form a polyamide 5X melt; alternatively, the first and second electrodes may be,

heating polyamide 5X resin to a molten state to form a polyamide 5X melt;

(2) spinning the polyamide 5X melt to form primary yarn;

(3) and processing the primary raw silk to obtain the polyamide 5X medium-strength silk.

6. The method of claim 5, wherein: in the step (1), the polymerization comprises the following steps:

(1-1) under the condition of nitrogen, uniformly mixing 1, 5-pentanediamine, dicarboxylic acid and water to prepare a salt solution of polyamide; wherein the molar ratio of the 1, 5-pentanediamine to the dicarboxylic acid is (1-1.05): 1;

(1-2) heating the salt solution of the polyamide, raising the pressure in the reaction system to 0.3-2.0MPa, exhausting, maintaining the pressure, then reducing the pressure to 0-0.2MPa, vacuumizing to-0.08-0.01 MPa of vacuum degree, wherein the pressure is gauge pressure, and obtaining polyamide 5X melt;

wherein, the temperature of the reaction system at the end of the pressure maintaining is preferably 232-265 ℃;

preferably, the temperature of the reaction system after the pressure reduction is finished is 245-280 ℃;

preferably, the temperature after the vacuum pumping is 260-280 ℃.

7. The method of claim 5, wherein: in the step (1), the polyamide 5X resin is polyamide 5X slices; and/or the presence of a gas in the gas,

the relative viscosity of the polyamide 5X resin 96% sulfuric acid is 2.5-3.0, preferably 2.6-2.9, more preferably 2.7-2.8; and/or the presence of a gas in the gas,

the water content of the polyamide 5X resin is 50-1500ppm, preferably 200-800ppm, more preferably 300-700ppm, and further preferably 400-600 ppm; and/or the presence of a gas in the gas,

the heating in the step (1) is carried out in a screw extruder which is divided into five zones for heating;

wherein the temperature of the first zone is 200-300 ℃; and/or the presence of a gas in the gas,

the temperature of the second zone is 230-320 ℃; and/or the presence of a gas in the gas,

the temperature of the three zones is 240 ℃ and 350 ℃; and/or the presence of a gas in the gas,

the temperature of the fourth area is 270-360 ℃; and/or the presence of a gas in the gas,

the temperature of the five areas is 270-400 ℃; and/or the presence of a gas in the gas,

preferably, the second zone temperature is greater than the first zone temperature;

preferably, the three zone temperature, the four zone temperature, or the five zone temperature is greater than the first zone temperature or the second zone temperature;

when the raw material for producing the filament in the polyamide 5X further comprises a comonomer and/or an additive, the comonomer and/or the additive is added in the step (1).

8. The method of claim 5, wherein: in the step (2), the spinning comprises the following steps:

spraying the polyamide 5X melt through a spinneret plate of a spinning manifold to form the primary yarn;

preferably, the temperature of the spinning manifold is 200-350 ℃, more preferably 210-330 ℃, further preferably 220-310 ℃, and further preferably 240-300 ℃; and/or the presence of a gas in the gas,

the pressure of a spinning assembly of the spinning manifold is 10-30MPa, preferably 15-25MPa, and further preferably 17-24 MPa; and/or the presence of a gas in the gas,

the number of holes of the spinneret is 48 to 576f, preferably 64 to 480f, more preferably 96 to 288f, and still more preferably 96 to 192 f; and/or the presence of a gas in the gas,

the spinneret has a spinneret draw ratio of 50 to 300, preferably 70 to 140, more preferably 80 to 110, still more preferably 90 to 100.

9. The method of claim 5, wherein: in the step (3), the processing includes the steps of:

cooling, oiling, stretching, heat setting and winding the primary raw silk to obtain the polyamide 5X medium-strength silk;

preferably, the cooling is by cross-air blowing; the air speed of the cross air blow is preferably 0.5-0.9m/s, more preferably 0.6-0.8 m/s; the air temperature of the cross air blower is preferably 15-32 ℃, more preferably 20-28 ℃, and further preferably 23-26 ℃; the humidity of the cross air blow is 60-80%, preferably 65-78%; and/or the presence of a gas in the gas,

the winding tension during the winding forming is 50-150cN, preferably 70-120cN, more preferably 75-110cN, and even more preferably 80-100 cN; and/or the presence of a gas in the gas,

the winding speed is 2000-3500m/min, preferably 2200-3000m/min, and more preferably 2200-2800 m/min.

10. The method of claim 9, wherein: the stretching process is more than two-stage stretching:

preferably, the stretching process is: feeding oiled as-spun yarns into a first pair of hot rollers through a godet roller, performing primary stretching between the first pair of hot rollers and a second pair of hot rollers, performing secondary stretching between the second pair of hot rollers and a third pair of hot rollers, and performing tension heat setting;

wherein, preferably:

the stretching multiple of the first-stage stretching is 3.0-4.5, and the stretching temperature is 60-180 ℃; and/or the presence of a gas in the gas,

the stretching multiple of the secondary stretching is 1.0-2.0, and the stretching temperature is 140-200 ℃; and/or the presence of a gas in the gas,

the total stretching multiple is 3.0-9.0, preferably 4.0-6.0; and/or the presence of a gas in the gas,

the temperature of the heat setting is 180-240 ℃, and preferably 200-230 ℃; and/or the presence of a gas in the gas,

the speed of the godet roller is 200-800m/min, preferably 400-600 m/min; and/or the presence of a gas in the gas,

the speed of the first heat roller is 300-900m/min, preferably 500-700 m/min; and/or the presence of a gas in the gas,

the speed of the second pair of hot rollers is 1500-2200m/min, preferably 1600-2000 m/min; and/or the presence of a gas in the gas,

the speed of the third pair of hot rolls is 2200-3000m/min, preferably 2200-2800 m/min; and/or the presence of a gas in the gas,

the first thermo roll has a number of turns of polyamide 5X filament winding of 4 to 8, preferably 5 to 7; and/or the presence of a gas in the gas,

the number of turns of the polyamide 5X fiber of the second pair of hot rolls is 6-12, preferably 7-10; and/or the presence of a gas in the gas,

the third pair of heated rolls has a number of polyamide 5X filament windings of 5 to 10, preferably 6 to 8.

Technical Field

The invention belongs to the technical field of polyamide materials, and relates to a polyamide 5X medium-strength yarn and a preparation method thereof.

Background

Medium strength yarn is a fiber having a breaking strength between that of civil yarn and that of low denier industrial yarn, and is used for the manufacture of fishing nets, industrial sewing threads, and the like. In the prior art, the strong yarn is generally produced by processing polyester serving as a raw material on spinning equipment of civil yarn. The orientation degree, crystallinity degree and breaking strength of the strong yarn in the polyester prepared by the method are low, and the dimensional stability is poor; and in the strand silk forming process, the stretching and setting temperature is low, the stretching multiplying power is small, and the method is difficult to be applied to the industrial field with higher requirements on the breaking strength and the dimensional stability.

Chinese patent CN 101205632A provides a process for producing medium-strength polyester filament yarn by melt direct spinning, chinese patent CN 105369375 a provides medium-strength yarn and a processing method, the medium-strength yarn materials reported in the 2 patents are all polyester, and the obtained polyester medium-strength yarn has not high mechanical properties, but poor wear resistance and alkali resistance. Therefore, a material having both good wear resistance and good alkali resistance is needed.

Polyamide 5X is a novel polyamide obtained by polymerizing 1, 5-pentanediamine and a dibasic acid, and has excellent mechanical properties and special properties which are not possessed by conventional polyesters. Due to the special structure of the polyamide 5X, the spinning process can not be carried out by carrying out the existing polyester process, on the basis, various properties of the polyamide 5X are further adjusted, and particularly, on the basis of meeting various mechanical strengths, the requirements of the existing market on the wear resistance and alkali resistance of the fiber can be met, so that the polyamide 5X has very important significance and value.

Disclosure of Invention

The first purpose of the invention is to provide a polyamide 5X medium-strength yarn which has high strength, low elongation and low heat shrinkage performance, and is excellent in abrasion resistance and alkali resistance.

The second purpose of the invention is to provide a preparation method of the polyamide 5X medium-strength yarn.

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

the production raw materials of the polyamide 5X medium-strength yarn at least comprise 1, 5-pentanediamine and dicarboxylic acid; alternatively, the first and second electrodes may be,

polyamide 5X obtained by polymerizing 1, 5-pentanediamine and dicarboxylic acid serving as monomers.

The breaking strength of the filaments in polyamide 5X may be 6.0-8.0 cN/dtex.

Preferably, the titer of the strong fiber in the polyamide 5X can be 110-.

Preferably, the breaking strength of the strong yarn in the polyamide 5X may be preferably 6.3 to 7.6cN/dtex, may be more preferably 6.5 to 7.2cN/dtex, and may be more preferably 6.7 to 7.0 cN/dtex.

Preferably, the elongation at break of the filaments in the polyamide 5X may be 14 to 25%, and may be preferably 14 to 16%.

Preferably, the dry heat shrinkage of the filaments in the polyamide 5X may be 3.0 to 8.0%, may be preferably 3.5 to 7.5%, and may be more preferably 4.0 to 6.0%.

Preferably, the boiling water shrinkage of the filaments in the polyamide 5X may be 2.0 to 7.0%, may be preferably 3.0 to 6.0%, and may be more preferably 4.0 to 5.0%.

Preferably, the crystallinity of the filament in the polyamide 5X may be 60 to 70%, may be preferably 61 to 69%, may be more preferably 62 to 68%, and may be more preferably 64 to 67%.

Preferably, the degree of orientation of the filaments in the polyamide 5X may be 70 to 80%, may be preferably 71 to 79%, may be further preferably 72 to 77%, and may be further preferably 73 to 76%.

Preferably, the 1, 5-pentanediamine is prepared from bio-based raw materials by a fermentation method or an enzymatic conversion method.

Preferably, the dicarboxylic acid has a carbon number of 4 to 18. The dicarboxylic acid comprises one or more of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, maleic acid and Δ 9-1, 18-octadecenedioic acid.

The raw material for producing the polyamide 5X medium-strength yarn can also comprise a comonomer.

The comonomers may include: any one or more of aliphatic dicarboxylic acid, alicyclic dicarboxylic acid, aromatic dicarboxylic acid, ethylenediamine, hexamethylenediamine, cyclohexanediamine, xylylenediamine, 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, p-aminomethylbenzoic acid, epsilon-caprolactam and omega-laurolactam.

The raw materials for producing the polyamide 5X medium-strength yarn can also comprise additives.

The additives may include: any one or more of a delustering agent, a flame retardant, an antioxidant, an ultraviolet absorber, an infrared absorber, a crystallization nucleating agent, a fluorescent brightener and an antistatic agent. The additive can be added in an amount of 0.001-10% of the total weight of the raw materials.

The preparation method of the polyamide 5X medium-strength yarn comprises the following steps:

(1) polymerizing 1, 5-pentanediamine and dicarboxylic acid to form a polyamide 5X melt; alternatively, the first and second electrodes may be,

heating polyamide 5X (polyamide 5X resin) to a molten state to form a polyamide 5X melt;

(2) spinning the polyamide 5X melt to form primary yarn;

(3) and treating the nascent fiber to obtain the polyamide 5X medium-strength fiber.

When the raw material for producing the filament in the polyamide 5X further comprises a comonomer, the comonomer is added in the step (1).

When the raw material for producing the filament in the polyamide 5X further comprises an additive, the additive is added in the step (1).

Preferably, in step (1), the polymerization comprises the steps of:

(1-1) under the condition of nitrogen, uniformly mixing 1, 5-pentanediamine, dicarboxylic acid and water to prepare a salt solution of polyamide; wherein the molar ratio of the 1, 5-pentanediamine to the dicarboxylic acid is (1-1.05): 1;

(1-2) heating the salt solution of the polyamide, raising the pressure in the reaction system to 0.3-2.0Mpa, exhausting, maintaining the pressure, then reducing the pressure to 0-0.2Mpa, vacuumizing to-0.08-0.01 Mpa of vacuum degree, wherein the pressure is gauge pressure, and obtaining the polyamide 5X melt.

When the raw material for producing the filament in polyamide 5X further comprises a comonomer, the comonomer is added in step (1-1).

When the raw material for producing the filament in the polyamide 5X further comprises an additive, the additive is added in the step (1-1).

Preferably, the temperature of the reaction system at the end of the pressure holding is 232-265 ℃.

Preferably, the temperature of the reaction system after the pressure reduction is finished is 245-280 ℃.

Preferably, the temperature after the vacuum pumping is 260-280 ℃.

In the step (1), the polyamide 5X resin is a polyamide 5X resin chip.

Preferably, the polyamide 5X resin may have a relative viscosity of 2.5 to 3.0, preferably 2.6 to 2.9, more preferably 2.7 to 2.8, of 96% sulfuric acid.

The polyamide 5X resin has a water content of 50-1500ppm, preferably 200-800ppm, more preferably 300-700ppm, and still more preferably 400-600 ppm.

In the step (1), the heating is carried out in a screw extruder which is divided into five zones for heating.

Wherein, preferably, the temperature of one zone is 200-300 ℃; and/or the temperature of the second zone is 230-320 ℃; and/or the temperature of the three zones is 240-350 ℃; and/or the temperature of the four areas is 270-360 ℃; and/or the temperature of the five zones is 270-400 ℃.

Preferably, the two-zone temperature is greater than the one-zone temperature.

Preferably, the three, four or five zone temperatures are greater than the one or two zone temperatures.

Preferably, when the raw material for producing the filament in the polyamide 5X further comprises an additive, the polyamide 5X is heated to a molten state to form a polyamide 5X melt, and then mixed with the additive.

Preferably, in the step (2), the spinning comprises the following steps:

and (3) spraying the polyamide 5X melt through a spinneret plate of a spinning manifold to form the primary yarn.

The temperature of the spinning beam may be 200-350 ℃, more preferably 210-330 ℃, more preferably 220-310 ℃, more preferably 240-300 ℃.

Preferably, the pressure of the spinning pack of the spinning beam may be 10 to 30MPa, may be preferably 15 to 25MPa, and may be further preferably 17 to 24 MPa.

Preferably, the number of holes of the spinneret plate may be 48 to 576f, preferably 64 to 480f, more preferably 96 to 288f, and still more preferably 96 to 192 f.

Preferably, the spinneret draw ratio of the spinneret plate may be 50 to 300, may be preferably 70 to 140, may be further preferably 80 to 110, and may be further preferably 90 to 100.

Preferably, in the step (3), the processing includes the steps of:

and cooling, oiling, stretching, heat setting and winding the as-spun yarn to obtain the polyamide 5X medium-strength yarn.

Wherein the cooling is by cross-air blowing.

Preferably, the wind speed of the cross-blown air may be preferably 0.5 to 0.9m/s, and may be more preferably 0.6 to 0.8 m/s.

Preferably, the air temperature of the cross-air blast may be preferably 15 to 32 ℃, may be more preferably 20 to 28 ℃, and may be further preferably 23 to 26 ℃.

Preferably, the humidity of the cross-air may be 60 to 80%, and may be preferably 65 to 78%.

Preferably, the winding tension at the time of the winding formation may be 50 to 150cN, may be preferably 70 to 120cN, may be further preferably 75 to 110cN, and may be further preferably 80 to 100 cN.

Preferably, the winding speed can be 2000-3500m/min, can be preferably 2200-3000m/min, and can be further preferably 2200-2800 m/min.

Preferably, the stretching is two-stage or more stretching.

Preferably, the stretching process is: feeding the oiled nascent yarn into a first pair of hot rollers through a godet roller, performing primary stretching between the first pair of hot rollers and a second pair of hot rollers, performing secondary stretching between the second pair of hot rollers and a third pair of hot rollers, and performing tension heat setting.

Preferably, the first stage drawing may have a drawing ratio of 3.0 to 4.5 and a drawing temperature of 60 to 180 ℃.

Preferably, the stretching ratio of the secondary stretching may be-1.0-2.0, and the stretching temperature may be 140-.

Preferably, the total draw ratio is 3.0 to 9.0, preferably 4.0 to 6.0.

Preferably, the heat-setting temperature may be 180-240 ℃, and may preferably be 200-230 ℃.

Preferably, the speed of the godet may be 200-800m/min, and may preferably be 400-600 m/min.

Preferably, the speed of the first pair of hot rolls may be 300-900m/min, and may preferably be 500-700 m/min.

Preferably, the speed of the second thermo roll may be 1500-.

Preferably, the speed of the third pair of hot rolls may be 2200-.

Preferably, the number of turns of the polyamide 5X fiber of the first thermo roll may be 4 to 8, and may preferably be 5 to 7.

Preferably, the number of turns of the polyamide 5X fiber of the second pair of hot rolls can be from 6 to 12, and can preferably be from 7 to 10.

Preferably, the number of turns of the polyamide 5X fiber of the third pair of heated rolls can be from 5 to 10, and can preferably be from 6 to 8.

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

firstly, the polyamide 5X medium-strength yarn has the characteristics of high strength, low elongation, low thermal shrinkage and the like.

Secondly, the polyamide 5X medium-strength yarn also has the advantages of good wear resistance, good alkali resistance, dimensional stability and the like, so that the polyamide 5X medium-strength yarn is widely applied to the fields of sewing threads, safety belts, ropes, fishing nets or filter cloth and the like.

Thirdly, the invention prepares the polyamide 5X medium-strength filament by carrying out primary and secondary stretching and high-temperature tension heat setting processes through three pairs of hot rollers, thereby reducing the stretching path and saving the production cost compared with the process using four pairs of hot rollers (application number: 201510881321.1).

Detailed Description

The invention relates to a polyamide 5X medium-strength yarn and a preparation method thereof.

< Polyamide 5X Medium Strength yarn >

The raw materials for producing polyamide 5X of the present invention at least include: 1, 5-pentanediamine and a dicarboxylic acid; or polyamide 5X obtained by polymerizing 1, 5-pentanediamine and dicarboxylic acid as monomers.

The dicarboxylic acids may include short chain dicarboxylic acids and/or long chain dicarboxylic acids. The short-chain dibasic acid can be any one selected from succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid or sebacic acid. The long-chain dicarboxylic acid may be any one selected from undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, maleic acid, and Δ 9-1, 18-octadecenedioic acid.

In polyamide 5X, X may take an integer from 2 to 18, for example, the polyamide 5X may include: polyamide 52, polyamide 54, polyamide 56, polyamide 510, polyamide 511, polyamide 512, polyamide 513, polyamide 514, polyamide 515, polyamide 516, polyamide 517, polyamide 518, and the like.

The 1, 5-pentanediamine may be produced by a biological fermentation method or a chemical method, and is preferably produced by a biological fermentation method in consideration of environmental influences.

The polyamide 5X medium strength yarn of the present invention may contain a copolymerized component or a mixed second component or third component in addition to the main component (the dibasic acid and the diamine) within a range not deviating from the object of the present invention. As the copolymerization component, for example: structural units derived from aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids. Further, the resin composition may contain a structural unit derived from an aliphatic diamine such as ethylenediamine or hexamethylenediamine, for example, an alicyclic diamine structural unit of cyclohexanediamine, an aromatic diamine structural unit of xylylenediamine, an amino acid such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, or p-aminomethylbenzoic acid, or a lactam such as epsilon-caprolactam or omega-laurolactam.

Further, in the present invention, the raw material for producing the filaments in the polyamide 5X may include various additives in addition to the above-mentioned 1, 5-pentanediamine and dicarboxylic acid according to the actual use requirement. Various additives including, but not limited to, delusterants, flame retardants, antioxidants, ultraviolet absorbers, infrared absorbers, crystal nucleating agents, fluorescent brighteners, antistatic agents, or the like may be copolymerized or mixed as needed in a total additive content of 0.001 to 10 wt%. The above additives may be added in the alternative or in any combination.

[ Properties of Polyamide 5X Medium Strength yarn ]

The properties of the filaments in the above polyamide 5X are as follows:

(1) fineness:

the titer of the polyamide 5X medium-strength fiber can be 110-1100dtex, can be preferably 210-990dtex, can be further preferably 220-880dtex, and can be further preferably 220-550 dtex.

(2) And breaking strength:

the breaking strength of the filaments in polyamide 5X may be 6.0 to 8.0cN/dtex, and may preferably be 6.3 to 7.6cN/dtex, and may more preferably be 6.5 to 7.2cN/dtex, and still more preferably be 6.7 to 7.0 cN/dtex.

(3) Elongation at break:

the elongation at break of the filaments in polyamide 5X may be 14 to 25%, and may preferably be 14 to 16%.

The breaking strength and breaking elongation are measured according to GB/T14344-.

(4) Dry heat shrinkage:

the dry heat shrinkage of the filament in polyamide 5X may be 3.0 to 8.0%, preferably 3.5 to 7.5%, and more preferably 4.0 to 6.0%.

Wherein the dry heat shrinkage is performed according to FZ/T50004, and the heat treatment temperature is 180 ℃.

(5) Boiling water shrinkage ratio:

the boiling water shrinkage of the polyamide 5X medium filament may be 2.0 to 7.0%, preferably 3.0 to 6.0%, and more preferably 4.0 to 5.0%.

Wherein, the boiling water shrinkage rate is measured by reference to GB/6505-2008 'test method for the thermal shrinkage rate of chemical fiber filaments', which specifically comprises the following steps: taking a section of polyamide 5X medium-strength fiber, pre-tensioning by 0.05 +/-0.005 cN/dtex, marking 50.00cm at the two ends of the middle of the section of polyamide 5X medium-strength fiber, wrapping the section of polyamide 5X medium-strength fiber with gauze, putting the section of polyamide 5X medium-strength fiber into boiling water to boil for 30min, drying a sample, measuring the length between two marked points, and calculating the boiling water shrinkage by adopting the following formula:

the boiling water shrinkage ratio ((initial length-length after shrinkage)/length after shrinkage) X100%.

(6) And crystallinity:

the crystallinity of the filament in polyamide 5X may be 60 to 70%, may be preferably 61 to 69%, may be more preferably 62 to 68%, and may be more preferably 64 to 67%.

(7) Degree of orientation:

the orientation degree of the filaments in the polyamide 5X may be 70 to 80%, may preferably be 71 to 79%, may more preferably be 72 to 77%, and may more preferably be 73 to 76%.

Fiber samples were analyzed using a D/max-2550PC X-ray diffractometer manufactured by Rigaku Corporation of Japan, the Cu target wavelengthThe voltage is 20-40kV, the current is 10-450mA, and the range of the measurement angle 2 theta is 5-40 degrees. Fully shearing a polyamide 5X medium-strength fiber sample for testing crystallization, wherein the mass of the sample is more than 0.2 g; the polyamide 5X medium strength fiber samples used for testing the crystallite orientation were carded in order, with a strand length of 30mm, and tested. And (4) performing data processing by using origin and other software, and analyzing and calculating the crystallinity and the orientation of the fiber.

Formula for calculating crystallinity:

wherein, sigma I_cIntegrated intensity of total diffraction for crystalline fraction; sigma I_aThe integrated intensity of scattering of the amorphous fraction.

Formula for calculating degree of orientation:

wherein H_iThe peak width at half maximum of the ith peak.

(8) And wear resistance:

the abrasion resistance of the fiber is tested by an LFY-109 type computer yarn abrasion resistance tester. And judging the wear resistance index by the wear resistance times of the fiber. The larger the number of times the fiber is resistant to abrasion, the better the resistance to abrasion.

(9) Alkali resistance:

the alkali resistance test method of the polyamide 5X medium-strength yarn is a sodium hydroxide solution soaking method. The polyamide 5X medium-strength filaments are soaked in a 5% sodium hydroxide solution for the same time (for example, 168 hours), and the mechanical properties (breaking strength) before and after soaking are measured to judge the alkali resistance.

< preparation method of Polyamide 5X Medium Strength yarn >

A preparation method of polyamide 5X medium-strength yarn comprises the following steps:

(1) polymerizing 1, 5-pentanediamine and dicarboxylic acid to form a polyamide 5X melt; alternatively, the first and second electrodes may be,

heating polyamide 5X (polyamide 5X resin) to a molten state to form a polyamide 5X melt;

(2) spinning the polyamide 5X melt to form primary yarn;

(3) and treating the nascent fiber to obtain the polyamide 5X medium-strength fiber.

When the raw material for producing the filament in polyamide 5X further comprises a comonomer, the comonomer is added in step (1).

When the raw material for producing the strong yarn in polyamide 5X further includes an additive, the additive is added in step (1).

In the step (1), the polymerization comprises the following steps:

(1-1) under the condition of nitrogen, uniformly mixing 1, 5-pentanediamine, dicarboxylic acid and water to prepare a salt solution of polyamide; wherein the molar ratio of the 1, 5-pentanediamine to the dicarboxylic acid is (1-1.05): 1;

(1-2) heating the salt solution of the polyamide, raising the pressure in the reaction system to 0.3-2.0Mpa, exhausting, maintaining the pressure, reducing the pressure to reduce the pressure in the reaction system to 0-0.2Mpa in gauge pressure, and vacuumizing to-0.08-0.01 Mpa in vacuum degree to obtain the polyamide 5X melt.

When the raw material for producing the filament in polyamide 5X further comprises a comonomer, the comonomer is added in step (1-1).

When the raw material for producing the filament in polyamide 5X further comprises an additive, the additive is added in step (1-1).

The temperature of the reaction system at the end of the pressure holding was 232-.

The temperature of the reaction system after the pressure reduction is finished is 245-280 ℃.

The temperature after vacuum pumping is 260 ℃ to 280 ℃.

In step (1), the polyamide 5X resin was a polyamide 5X chip, which was prepared according to the preparation method disclosed in CN 104031263 a.

Among them, since polyamide 5X resin has a strong water absorption property, it is necessary to dry it before melting by heating, and it is preferable to dry it at 80 to 130 ℃ for 10 to 30 hours, if necessary, and then melt it by heating in a single-screw extruder after drying.

The water content of the polyamide 5X resin is 50-1500ppm, preferably 200-800ppm, more preferably 300-700ppm, and further preferably 400-600 ppm.

The polyamide 5X resin may have a relative viscosity of 96% sulfuric acid of 2.5 to 3.0, may preferably be 2.6 to 2.9, and may more preferably be 2.7 to 2.8.

The relative viscosity was determined as follows:

the relative viscosity of the polyamide 5X resin is measured by a concentrated sulfuric acid method with an Ubbelohde viscometer, and the method comprises the following steps: the dried polyamide 5X chips or staple fiber samples thereof were accurately weighed at 0.25. + -. 0.0002g, dissolved in 50mL of concentrated sulfuric acid (96%), and the flow-through time t of the concentrated sulfuric acid was measured and recorded in a thermostatic water bath at 25 ℃₀And polyamide 5X chips orThe flowing time t of the short fiber sample solution.

The relative viscosity is calculated by the formula: relative viscosity VN ═ t/t⁰；

t-solution flow time;

t₀-solvent flow time.

The heating in the step (1) is carried out in a screw extruder which is divided into five zones for heating, wherein the temperature of the first zone is 200-300 ℃, the temperature of the second zone is 230-320 ℃, the temperature of the third zone is 240-350 ℃, the temperature of the fourth zone is 270-360 ℃, and the temperature of the fifth zone is 270-400 ℃.

Preferably, the second zone temperature is greater than the first zone temperature; the temperature of the three zone, the temperature of the four zone or the temperature of the five zone is higher than the temperature of the first zone or the temperature of the second zone.

When the raw material for producing the filament in the polyamide 5X also comprises the additive, the polyamide 5X is heated to a molten state to form a polyamide 5X melt, and then the polyamide 5X melt is mixed with the additive.

In the step (2), the spinning comprises the following steps:

and (3) spraying the polyamide 5X melt through a spinneret plate of a spinning manifold to form the primary yarn.

The temperature of the spinning beam may be 200-350 ℃, more preferably 210-330 ℃, more preferably 220-310 ℃, and still more preferably 240-300 ℃.

The pressure of the spinning pack of the spinning beam may be 10 to 30MPa, preferably 15 to 25MPa, and more preferably 17 to 24 MPa.

The number of holes of the spinneret may be 48 to 576f, may preferably be 64 to 480f, may more preferably be 96 to 288f, and may more preferably be 96 to 192 f.

The spinneret has a spinneret draw ratio of 50 to 300, preferably 70 to 140, more preferably 80 to 110, still more preferably 90 to 100.

In the step (3), the processing includes the steps of:

and cooling, oiling, stretching, heat setting and winding the as-spun yarn to obtain the polyamide 5X medium-strength yarn.

Wherein the cooling is performed by cross air blowing; the air speed of the cross air blow can be preferably 0.5-0.9m/s, and can be more preferably 0.6-0.8 m/min; the air temperature of the cross air blow can be preferably 15-32 ℃, can be more preferably 20-28 ℃, and can be further preferably 23-26 ℃; the humidity of the cross-air may be 60 to 80%, and may preferably be 65 to 78%.

The winding speed may be 2000-3500m/min, preferably 2200-3000m/min, and more preferably 2200-2800 m/min.

The stretching process is more than two-stage stretching, and specifically comprises the following steps: the oiled nascent yarn enters a winding room through a spinning channel, is fed into a first pair of hot rollers through a godet roller, is subjected to primary stretching between the first pair of hot rollers and a second pair of hot rollers, is subjected to secondary stretching between the second pair of hot rollers and a third pair of hot rollers, and is subjected to tension heat setting.

Tension heat setting means heat setting under the fiber tension state, and tension heat setting is mainly performed between the second pair of hot rollers and the third pair of hot rollers.

Wherein the stretching ratio of the first-stage stretching can be 3.0-4.5, the stretching temperature can be 60-180 ℃, and the first-stage stretching is the main stretching.

The stretching ratio of the secondary stretching may be 1.0-2.0, and the stretching temperature may be 140-.

The total stretching ratio may be 3.0 to 9.0, and may preferably be 4.0 to 6.0.

Actually, the stretching process may be three-stage stretching, four-stage stretching, five-stage stretching or six-stage stretching, and the two-stage stretching is preferable in the present embodiment; the stretching ratio may preferably be 4.0 to 6.0, and the stretching temperature may preferably be 60 to 150 ℃.

The heat-setting temperature may be 180 ℃ to 240 ℃, and may preferably be 200 ℃ to 230 ℃.

The speed of the godet roller may be 200-800m/min, and may preferably be 400-600 m/min.

The speed of the first heat roller may be 300-900m/min, and may preferably be 500-700 m/min.

The speed of the second thermo roll may be 1500-.

The speed of the third pair of hot rolls may be 2200-.

The number of turns of the polyamide 5X fiber of the first thermo roll may be 4 to 8, and may preferably be 5 to 7.

The number of turns of the polyamide 5X fiber of the second pair of hot rolls can be 6 to 12 and can preferably be 7 to 10.

The number of turns of the polyamide 5X filament of the third pair of heated rolls can be from 5 to 10 and can preferably be from 6 to 8.

The present invention will be further described with reference to examples and comparative examples.