Preparation method of low-melting-point antistatic nylon fiber

Abstract

The invention relates to the technical field of nylon fibers, and discloses a preparation method of a low-melting-point antistatic nylon fiber, which adopts antistatic dispersion liquid, pentamethylene diamine, adipic acid, caprolactam, dodecane diamine and dodecanedioic acid as raw materials for random copolymerization to prepare the low-melting-point antistatic nylon fiber. The antistatic dispersion liquid is prepared from nano antimony doped tin dioxide; the melting point of the nylon fiber prepared by the method is 95-120 DEG C, the volume resistivity is 4E8-8E8 omega.cm, the surface resistivity is 2E9-6E9 omega.cm, the moisture absorption performance is that the relative viscosity is 2.4-2.8, the breaking strength is 2.7-3.2 CN / dtex, and the elongation at break is 30-40%. Compared with conventional nylon 6, the nylon fiber has the characteristics of low melting point, high antistatic performance, excellent moisture absorption performance and high toughness.

Description

Technical Field

[0001] The invention relates to the technical field of nylon fibers, in particular to a method for preparing low-melting-point antistatic nylon fibers. Background Art

[0002] Low-melting-point nylon is made by destroying the symmetry and regularity of the molecular chain of nylon materials. Compared with conventional nylon materials, its crystallization ability and melting point are significantly lower. In addition, compared with conventional nylon, low-melting-point nylon has lower rigidity, higher toughness, higher transparency and better processing performance. Therefore, it is widely used in hot-melt fibers, hot-melt adhesives and other fields.

[0003] The preparation method of low-melting point nylon fiber mainly adopts the method of blending and industrial polymerization modification, such as the preparation method of a low-melting point copolyamide disclosed in Publication No. CN102863616A, and another example is a high-performance low-melting point nylon 6 and its preparation method disclosed in Publication No. CN102408705A. The melting point of low-melting point nylon materials in the existing technology is still relatively high, so it is difficult to apply in the field of clothing. In addition, the low-melting point nylon materials in the existing technology also have the problems of poor hygroscopicity, easy to generate static electricity, low water washing resistance, etc. Therefore, it is necessary to develop a nylon fiber that has low melting point, antistatic and water washing resistance. Summary of the invention

[0004] The invention aims at the problem that low-melting-point nylon fiber in the prior art has poor hygroscopicity, is easy to generate static electricity, has poor water washing resistance and is difficult to be applied in the field of clothing, and provides a preparation method of low-melting-point antistatic nylon fiber; the method adopts antistatic dispersion liquid, pentamethylenediamine, adipic acid, caprolactam, dodecanediamine and dodecanediacid as raw materials for random copolymerization to prepare low-melting-point antistatic nylon fiber; the antistatic dispersion liquid is prepared by nano-antimony doped tin dioxide; the nano-antimony doped tin dioxide has excellent antistatic performance, and the antistatic performance of the nylon material can be significantly improved by adding the nano-antimony doped tin dioxide to the nylon fiber material; pentamethylenediamine and adipic acid can be polymerized to form PA56; dodecanediamine and dodecanediacid can be polymerized to form PA1212; the melting point of the nylon material can be significantly reduced by introducing PA56 and PA1212, so that the melting point of the nylon material is reduced to below 120°C; in addition, the introduction of PA56 can also improve the hygroscopicity of the nylon material; the introduction of PA1212 can also significantly improve the water washing resistance of the material.

[0005] The specific technical scheme of the present invention is: A method for preparing low-melting-point antistatic nylon fiber comprises the following steps: dispersing nano antimony-doped tin dioxide in water and grinding to prepare a dispersion liquid; adding the antistatic dispersion liquid, pentamethylenediamine, adipic acid, caprolactam, dodecanediamine, dodecanediacid, an antioxidant, a catalyst and deionized water into a polymerization device for polymerization reaction to prepare slices; and melt-spinning the slices to prepare low-melting-point antistatic nylon fiber.

[0006] The invention provides a method for preparing low-melting-point antistatic nylon fiber. The method adopts antistatic dispersion liquid, pentamethylenediamine, adipic acid, caprolactam, dodecanediamine and dodecanediacid as raw materials for random copolymerization to prepare low-melting-point antistatic nylon fiber. The nylon fiber prepared by the method has a melting point of 95-120 DEG C, a volume resistivity of 4E8-8E8Ω·cm, a surface resistivity of 2E9-6E9Ω, a hygroscopic property, a relative viscosity of 2.4-2.8, a breaking strength of 2.7-3.2CN / dtex, and a breaking elongation of 30-40%. Compared with conventional nylon 6, the nylon fiber has the characteristics of low melting point, high antistatic property, excellent hygroscopic property and high toughness.

[0007] Preferably, the mass of caprolactam is 250 to 398.8 g.

[0008] Preferably, the mass of pentamethylenediamine is 60.04 to 113.16 g.

[0009] Preferably, the mass of adipic acid is 85.86 to 161.84 g.

[0010] Preferably, the mass of dodecanediamine is 211.8 to 220.99 g.

[0011] Preferably, the mass of dodecanedioic acid is 243.5 to 254.01 g.

[0012] Preferably, the mass of the dispersion is 7.5 to 33.3 g.

[0013] Preferably, the particle size of the nano antimony-doped tin dioxide is 50-100 nm.

[0014] Preferably, the catalyst is one or more of p-toluenesulfonic acid, sodium hydroxide, potassium hydroxide, sodium hypophosphite and zinc acetate.

[0015] Preferably, the antioxidant is one or both of antioxidant 1098 and antioxidant SEED.

[0012] Preferably, the conditions of the polymerization reaction include: 0.1 MPa nitrogen sealing, salt formation temperature 70-80°C, salt formation time 1-2 h; ring opening temperature 220-235°C, ring opening pressure 0.5-0.7 MPa, pressure-maintaining ring opening time 1-2 h; condensation temperature 250-260°C, condensation vacuum 0.08-0.09 MPa.

[0017] Preferably, the melt spinning conditions include: a screw temperature of 210-250°C and a spinning box temperature of 240-260°C.

[0018] Preferably, the chips are vacuum dried before melt spinning.

[0019] Preferably, the vacuum drying temperature is 60-80°C.

[0020] Preferably, the concentration of the dispersion is 10-20 wt %.

[0021] Preferably, the amount of the nano antimony-doped tin dioxide added is 0.5-1.5 wt %.

[0022] Preferably, the vacuum drying temperature of the low-melting-point antistatic nylon is 60-80°C, and the drying time is 24h; the screw temperature of the screw extruder is 210-250°C, and the spinning box temperature is 240-260°C; the spinneret of the spinneret assembly is 36F; the side-blowing cooling temperature is 15°C, and the relative humidity is 60%; the GR1 temperature is 50-60°C, and the GR2 temperature is 60-75°C; the winding speed is 2400m / min, and the drafting multiple is 3 times.

[0023] Compared with the prior art, this application has the following technical effects: The invention provides a method for preparing low-melting-point antistatic nylon fiber. The method adopts antistatic dispersion liquid, pentamethylenediamine, adipic acid, caprolactam, dodecanediamine and dodecanediacid as raw materials for random copolymerization to prepare low-melting-point antistatic nylon fiber. The nylon fiber prepared by the method has a melting point of 95-120 DEG C, a volume resistivity of 4E8-8E8Ω·cm, a surface resistivity of 2E9-6E9Ω, a hygroscopic property, a relative viscosity of 2.4-2.8, a breaking strength of 2.7-3.2CN / dtex, and a breaking elongation of 30-40%. Compared with conventional nylon 6, the nylon fiber has the characteristics of low melting point, high antistatic property, excellent hygroscopic property and high toughness. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the embodiments.

[0025] Embodiment 1: A method for preparing low-melting-point antistatic nylon fiber comprises the following steps: Preparation of dispersion: Add 20g of nano antimony-doped tin dioxide (particle size of 50-100nm) into 200ml of deionized water and stir evenly at a speed of 80rpm to form a suspension emulsion dispersion system. Ultrasonic disperse the suspension emulsion dispersion system for 1h, then add it to a ball mill and wet mill for 60min at a grinding rate of 1600r / min, 0.6mm pure zirconia beads and 18°C ​​cooling water to prepare a 10wt% dispersion.

[0026] Preparation of low-melting antistatic nylon chips: 250g of caprolactam, 113.16g of pentamethylenediamine, 161.84g of adipic acid, 220.99g of dodecanediamine, 254.01g of dodecanediacid, 10g of dispersion, 291g of deionized water, 1g of sodium hypophosphite and 1g of antioxidant SEED were added to the polymerization kettle, replaced with nitrogen three times, and then 0.1MPa nitrogen seal was applied, and the salt was formed at 80°C for 1h, the temperature was raised to 220°C and the pressure was maintained at 0.7MPa for 2h to open the ring, and after the pressure was released to normal pressure, the temperature was raised to 250°C, vacuumed to 0.08MPa, polycondensed for 1.5h, and drawn into strips and pelletized to make low-melting antistatic nylon chips.

[0027] Preparation of low-melting-point antistatic nylon fiber: low-melting-point antistatic nylon slices are placed in a vacuum drum drying device and dried at 60°C for 4 hours, then heated to 80°C and dried for 20 hours, and the dried slices are placed in the hopper of a screw extruder, melt-extruded by the screw extruder, and then enter the spinneret assembly for spinning to form low-melting-point antistatic nylon fiber. The temperature of the first zone of the screw extruder is 220°C, the temperature of the second zone is 250°C, the temperature of the third zone is 255°C, the temperature of the composite spinning box is 260°C, the spinneret of the spinneret assembly is 36F, the side blowing cooling temperature is 20°C, the relative humidity is 60%, the GR1 temperature is 60°C, the GR2 temperature is 75°C, the winding speed is 2400m / min, the drafting multiple is 3 times, and the linear density of the low-melting-point antistatic nylon fiber is 121dtex.

[0028] Embodiment 2: A method for preparing low-melting-point antistatic nylon fiber comprises the following steps: Preparation of dispersion: Add 40g of nano antimony-doped tin dioxide (particle size of 50-100nm) into 200ml of deionized water and stir evenly at a speed of 80rpm to form a suspension emulsion dispersion system. Ultrasonic disperse the suspension emulsion dispersion system for 2h, then add it to a ball mill and wet mill for 80min at a grinding rate of 1600r / min, 0.3mm pure zirconia beads and 18°C ​​cooling water to prepare a 20wt% dispersion.

[0029] Preparation of low-melting-point antistatic nylon chips: 326g of caprolactam, 85.88g of pentamethylenediamine, 122.82g of adipic acid, 216.48g of dodecanediamine, 248.82g of dodecanediacid, 7.5g of dispersion, 494g of deionized water, 1g of sodium hydroxide and 0.5g of antioxidant 1098 were added to a polymerization kettle, replaced with nitrogen three times, and then 0.1MPa of nitrogen sealing was applied, and the salt was formed at 80°C for 2h, the temperature was raised to 235°C and the pressure was maintained at 0.6MPa for 1h to open the loop, and after the pressure was released to normal pressure, the temperature was raised to 250°C, vacuumed to 0.09MPa, polycondensed for 2h, and drawn into strips and pelletized to make low-melting-point antistatic nylon chips.

[0030] Preparation of low-melting-point antistatic nylon fiber: low-melting-point antistatic nylon slices are placed in a vacuum drum drying device and dried at 60°C for 4 hours, then heated to 80°C and dried for 20 hours, and the dried slices are placed in the hopper of a screw extruder, melt-extruded by the screw extruder, and then enter the spinneret assembly for spinning to form low-melting-point antistatic nylon fiber. The temperature of the first zone of the screw extruder is 210°C, the temperature of the second zone is 245°C, the temperature of the third zone is 250°C, the temperature of the composite spinning box is 255°C, the spinneret of the spinneret assembly is 36F, the side blowing cooling temperature is 15°C, the relative humidity is 60%, the GR1 temperature is 50°C, the GR2 temperature is 60°C, the winding speed is 2400m / min, the drafting multiple is 3 times, and the linear density of the low-melting-point antistatic nylon fiber is 135dtex.

[0031] Embodiment 3: A method for preparing low-melting-point antistatic nylon fiber comprises the following steps: Preparation of dispersion: Add 30g of nano antimony-doped tin dioxide (particle size of 50-100nm) into 200ml of deionized water and stir evenly at a speed of 80rpm to form a suspension emulsion dispersion system. Ultrasonic disperse the suspension emulsion dispersion system for 2h, then add it to a ball mill and wet mill for 70min at a grinding rate of 1600r / min, 0.3mm pure zirconia beads and 18°C ​​cooling water to prepare a 15wt% dispersion.

[0032] Preparation of low-melting antistatic nylon chips: 398.8g of caprolactam, 60.04g of pentamethylenediamine, 85.86g of adipic acid, 211.8g of dodecanediamine, 243.5g of dodecanediacid, 33.3g of dispersion, 371.7g of deionized water, 2g of sodium hydroxide and 1g of antioxidant 1098 were added to the polymerization kettle, replaced with nitrogen three times, and then 0.1MPa nitrogen seal was applied, and the salt was formed at 80°C for 2h, the temperature was raised to 235°C and the pressure was maintained at 0.6MPa for 1h to open the loop, and after the pressure was released to normal pressure, the temperature was raised to 250°C, vacuumed to 0.09MPa, polycondensed for 2h, and drawn into strips and pelletized to make low-melting antistatic nylon chips.

[0033] Preparation of low-melting-point antistatic nylon fiber: low-melting-point antistatic nylon slices are placed in a vacuum drum drying device and dried at 60°C for 4 hours, then heated to 80°C and dried for 20 hours, and the dried slices are placed in the hopper of a screw extruder, melt-extruded by the screw extruder, and then enter the spinneret assembly for spinning to form low-melting-point antistatic nylon fiber. The temperature of the first zone of the screw extruder is 210°C, the temperature of the second zone is 245°C, the temperature of the third zone is 250°C, the temperature of the composite spinning box is 255°C, the spinneret of the spinneret assembly is 36F, the side blowing cooling temperature is 10°C, the relative humidity is 60%, the GR1 temperature is 50°C, the GR2 temperature is 60°C, the winding speed is 2400m / min, the drafting multiple is 3 times, and the linear density of the low-melting-point antistatic nylon fiber is 135dtex.

[0034] Comparative Example 1: Compared with Example 1, Comparative Example 1 uses nano-conductive titanium dioxide as antistatic powder, and includes the following steps: Preparation of dispersion: Add 20g of nano-conductive titanium dioxide (particle size of 50-100nm) into 200ml of deionized water and stir evenly at a speed of 80rpm to form a suspension emulsion dispersion system. Ultrasonic disperse the suspension emulsion dispersion system for 1h, then add it to a ball mill and wet mill for 60min at a grinding rate of 1600r / min, 0.6mm pure zirconia beads and 18°C ​​cooling water to prepare a 10wt% dispersion.

[0035] Preparation of low-melting antistatic nylon chips: 250g of caprolactam, 113.16g of pentamethylenediamine, 161.84g of adipic acid, 220.99g of dodecanediamine, 254.01g of dodecanediacid, 10g of dispersion, 291g of deionized water, 1g of sodium hypophosphite and 1g of antioxidant SEED were added to the polymerization kettle, replaced with nitrogen three times, and then 0.1MPa nitrogen seal was applied, and the salt was formed at 80°C for 1h, the temperature was raised to 220°C and the pressure was maintained at 0.7MPa for 2h to open the ring, and after the pressure was released to normal pressure, the temperature was raised to 250°C, vacuumed to 0.08MPa, polycondensed for 1.5h, and drawn into strips and pelletized to make low-melting antistatic nylon chips.

[0036] Preparation of low-melting-point antistatic nylon fiber: low-melting-point antistatic nylon slices are placed in a vacuum drum drying device and dried at 60°C for 4 hours, then heated to 80°C and dried for 20 hours, and the dried slices are placed in the hopper of a screw extruder, melt-extruded by the screw extruder, and then enter the spinneret assembly for spinning to form low-melting-point antistatic nylon fiber. The temperature of the first zone of the screw extruder is 220°C, the temperature of the second zone is 250°C, the temperature of the third zone is 255°C, the temperature of the composite spinning box is 265°C, the spinneret of the spinneret assembly is 36F, the side blowing cooling temperature is 20°C, the relative humidity is 60%, the GR1 temperature is 60°C, the GR2 temperature is 75°C, the winding speed is 2400m / min, the drafting multiple is 3 times, and the linear density of the low-melting-point antistatic nylon fiber is 190dtex.

[0037] Comparative Example 2: Compared with Example 1, Comparative Example 2 uses nano-aluminum-doped zinc oxide as antistatic powder, which includes the following steps: preparing a dispersion: adding 20g of nano-aluminum-doped zinc oxide (particle size of 50-100nm) to 200ml of deionized water and stirring evenly at a speed of 80rpm to form a suspension emulsion dispersion system, ultrasonically dispersing the suspension emulsion dispersion system for 1h, and then adding it to a ball mill and wet-milling it for 60min at a grinding rate of 1600r / min, 0.6mm pure zirconium oxide beads and 18°C ​​cooling water to prepare a 10wt% dispersion.

[0038] Preparation of low-melting antistatic nylon chips: 250g of caprolactam, 113.16g of pentamethylenediamine, 161.84g of adipic acid, 220.99g of dodecanediamine, 254.01g of dodecanediacid, 10g of dispersion, 291g of deionized water, 1g of sodium hypophosphite and 1g of antioxidant SEED were added to the polymerization kettle, replaced with nitrogen three times, and then 0.1MPa nitrogen seal was applied, and the salt was formed at 80°C for 1h, the temperature was raised to 220°C and the pressure was maintained at 0.7MPa for 2h to open the ring, and after the pressure was released to normal pressure, the temperature was raised to 250°C, vacuumed to 0.08MPa, polycondensed for 1.5h, and drawn into strips and pelletized to make low-melting antistatic nylon chips.

[0039] Preparation of low-melting-point antistatic nylon fiber: low-melting-point antistatic nylon slices are placed in a vacuum drum drying device and dried at 60°C for 4 hours, then heated to 80°C and dried for 20 hours, and the dried slices are placed in the hopper of a screw extruder, melt-extruded by the screw extruder, and then enter the spinneret assembly for spinning to form low-melting-point antistatic nylon fiber. The temperature of the first zone of the screw extruder is 220°C, the temperature of the second zone is 250°C, the temperature of the third zone is 255°C, the temperature of the composite spinning box is 260°C, the spinneret of the spinneret assembly is 36F, the side blowing cooling temperature is 20°C, the relative humidity is 60%, the GR1 temperature is 60°C, the GR2 temperature is 75°C, the winding speed is 2400m / min, the drafting multiple is 3 times, and the linear density of the low-melting-point antistatic nylon fiber is 140dtex.

[0040] Comparative Example 3: Compared with Example 1, Comparative Example 3 uses nano tin dioxide as antistatic powder, and includes the following steps: Preparation of dispersion: Add 20g of nano-tin dioxide (particle size of 50-100nm) into 200ml of deionized water and stir at 80rpm to form a suspension dispersion system. Ultrasonic disperse the suspension dispersion system for 1h, then add it to a ball mill and wet mill for 60min at a grinding rate of 1600r / min, 0.6mm pure zirconium oxide beads and 18°C ​​cooling water to prepare a 10wt% dispersion.

[0041] Preparation of low-melting antistatic nylon chips: 250g of caprolactam, 113.16g of pentamethylenediamine, 161.84g of adipic acid, 220.99g of dodecanediamine, 254.01g of dodecanediacid, 10g of dispersion, 291g of deionized water, 1g of sodium hypophosphite and 1g of antioxidant SEED were added to the polymerization kettle, replaced with nitrogen three times, and then 0.1MPa nitrogen seal was applied, and the salt was formed at 80°C for 1h, the temperature was raised to 220°C and the pressure was maintained at 0.7MPa for 2h to open the ring, and after the pressure was released to normal pressure, the temperature was raised to 250°C, vacuumed to 0.08MPa, polycondensed for 1.5h, and drawn into strips and pelletized to make low-melting antistatic nylon chips.

[0042] Preparation of low-melting-point antistatic nylon fiber: low-melting-point antistatic nylon slices are placed in a vacuum drum drying device and dried at 60°C for 4 hours, then heated to 80°C and dried for 20 hours, and the dried slices are placed in the hopper of a screw extruder, melt-extruded by the screw extruder, and then enter the spinneret assembly for spinning to form low-melting-point antistatic nylon fiber. The temperature of the first zone of the screw extruder is 220°C, the temperature of the second zone is 250°C, the temperature of the third zone is 255°C, the temperature of the composite spinning box is 260°C, the spinneret of the spinneret assembly is 36F, the side blowing cooling temperature is 20°C, the relative humidity is 60%, the GR1 temperature is 60°C, the GR2 temperature is 75°C, the winding speed is 2400m / min, the drafting multiple is 3 times, and the linear density of the low-melting-point antistatic nylon fiber is 135dtex.

[0043] Comparative Example 4: Compared with Example 1, the amount of pentamethylenediamine and adipic acid used in Comparative Example 4 is reduced, and the method comprises the following steps: Preparation of dispersion: Add 20g of nano antimony-doped tin dioxide (particle size of 50-100nm) into 200ml of deionized water and stir evenly at a speed of 80rpm to form a suspension emulsion dispersion system. Ultrasonic disperse the suspension emulsion dispersion system for 1h, then add it to a ball mill and wet mill for 60min at a grinding rate of 1600r / min, 0.6mm pure zirconia beads and 18°C ​​cooling water to prepare a 10wt% dispersion.

[0044] Preparation of low-melting antistatic nylon chips: 475g of caprolactam, 20.57g of pentamethylenediamine, 29.43g of adipic acid, 220.99g of dodecanediamine, 254.01g of dodecanediacid, 10g of dispersion, 291g of deionized water, 1g of sodium hypophosphite and 1g of antioxidant SEED were added to the polymerization kettle, replaced with nitrogen three times, and then 0.1MPa nitrogen seal was applied, and the salt was formed at 80°C for 1h, the temperature was raised to 220°C and the pressure was maintained at 0.7MPa for 2h to open the ring, and after the pressure was released to normal pressure, the temperature was raised to 250°C, vacuumed to 0.08MPa, polycondensed for 1.5h, and drawn into strips and pelletized to make low-melting antistatic nylon chips.

[0045] Preparation of low-melting-point antistatic nylon fiber: low-melting-point antistatic nylon slices are placed in a vacuum drum drying device and dried at 60°C for 4 hours, then heated to 80°C and dried for 20 hours, and the dried slices are placed in the hopper of a screw extruder, melt-extruded by the screw extruder, and then enter the spinneret assembly for spinning to form low-melting-point antistatic nylon fiber. The temperature of the first zone of the screw extruder is 220°C, the temperature of the second zone is 250°C, the temperature of the third zone is 255°C, the temperature of the composite spinning box is 260°C, the spinneret of the spinneret assembly is 36F, the side blowing cooling temperature is 20°C, the relative humidity is 60%, the GR1 temperature is 60°C, the GR2 temperature is 75°C, the winding speed is 2400m / min, the drafting multiple is 3 times, and the linear density of the low-melting-point antistatic nylon fiber is 124dtex.

[0046] Comparative Example 5: Compared with Example 1, the dosage of dodecanediamine and dodecanedioic acid in Comparative Example 5 is reduced, and the method comprises the following steps: Preparation of dispersion: Add 20g of nano antimony-doped tin dioxide (particle size of 50-100nm) into 200ml of deionized water and stir evenly at a speed of 80rpm to form a suspension emulsion dispersion system. Ultrasonic disperse the suspension emulsion dispersion system for 1h, then add it to a ball mill and wet mill for 60min at a grinding rate of 1600r / min, 0.6mm pure zirconia beads and 18°C ​​cooling water to prepare a 10wt% dispersion.

[0047] Preparation of low-melting antistatic nylon chips: 525g of caprolactam, 113.16g of pentamethylenediamine, 161.84g of adipic acid, 93.05g of dodecanediamine, 106.95g of dodecanediacid, 10g of dispersion, 291g of deionized water, 1g of sodium hypophosphite and 1g of antioxidant SEED were added to the polymerization kettle, replaced with nitrogen three times, and then 0.1MPa nitrogen seal was applied, and the salt was formed at 80°C for 1h, the temperature was raised to 220°C and the pressure was maintained at 0.7MPa for 2h to open the ring, and after the pressure was released to normal pressure, the temperature was raised to 250°C, vacuumed to 0.08MPa, polycondensed for 1.5h, and drawn into strips and pelletized to make low-melting antistatic nylon chips.

[0048] Preparation of low-melting-point antistatic nylon fiber: low-melting-point antistatic nylon slices are placed in a vacuum drum drying device and dried at 60°C for 4 hours, then heated to 80°C and dried for 20 hours, and the dried slices are placed in the hopper of a screw extruder, melt-extruded by the screw extruder, and then enter the spinneret assembly for spinning to form low-melting-point antistatic nylon fiber. The temperature of the first zone of the screw extruder is 220°C, the temperature of the second zone is 250°C, the temperature of the third zone is 255°C, the temperature of the composite spinning box is 260°C, the spinneret of the spinneret assembly is 36F, the side blowing cooling temperature is 20°C, the relative humidity is 60%, the GR1 temperature is 60°C, the GR2 temperature is 75°C, the winding speed is 2400m / min, the drafting multiple is 3 times, and the linear density of the low-melting-point antistatic nylon fiber is 122dtex.

[0049] Comparative Example 6: Compared with Example 1, the amount of nano-antimony-doped tin oxide added in Comparative Example 6 is too small, and the method comprises the following steps: Preparation of dispersion: Add 20g of nano antimony-doped tin dioxide (particle size of 50-100nm) into 200ml of deionized water and stir evenly at a speed of 80rpm to form a suspension emulsion dispersion system. Ultrasonic disperse the suspension emulsion dispersion system for 1h, then add it to a ball mill and wet mill for 60min at a grinding rate of 1600r / min, 0.6mm pure zirconia beads and 18°C ​​cooling water to prepare a 10wt% dispersion.

[0050] Preparation of low-melting antistatic nylon chips: 250g of caprolactam, 113.16g of pentamethylenediamine, 161.84g of adipic acid, 220.99g of dodecanediamine, 254.01g of dodecanediacid, 5g of dispersion, 295.5g of deionized water, 1g of sodium hypophosphite and 1g of antioxidant SEED were added to the polymerization kettle, replaced with nitrogen three times, and then 0.1MPa nitrogen seal was applied, and the salt was formed at 80°C for 1h, the temperature was raised to 220°C and the pressure was maintained at 0.7MPa for 2h to open the ring, and after the pressure was released to normal pressure, the temperature was raised to 250°C, vacuumed to 0.08MPa, polycondensed for 1.5h, and drawn into strips and pelletized to make low-melting antistatic nylon chips.

[0051] Preparation of low-melting-point antistatic nylon fiber: low-melting-point antistatic nylon slices are placed in a vacuum drum drying device and dried at 60°C for 4 hours, then heated to 80°C and dried for 20 hours, and the dried slices are placed in the hopper of a screw extruder, melt-extruded by the screw extruder, and then enter the spinneret assembly for spinning to form low-melting-point antistatic nylon fiber. The temperature of the first zone of the screw extruder is 220°C, the temperature of the second zone is 250°C, the temperature of the third zone is 255°C, the temperature of the composite spinning box is 260°C, the spinneret of the spinneret assembly is 36F, the side blowing cooling temperature is 20°C, the relative humidity is 60%, the GR1 temperature is 60°C, the GR2 temperature is 75°C, the winding speed is 2400m / min, the drafting multiple is 3 times, and the linear density of the low-melting-point antistatic nylon fiber is 121dtex.

[0052] Comparative Example 7: Compared with Example 1, the amount of nano-antimony doped tin oxide added in Comparative Example 5 is too much, and includes the following steps: Preparation of dispersion: Add 20g of nano antimony-doped tin dioxide (particle size of 50-100nm) into 200ml of deionized water and stir evenly at a speed of 80rpm to form a suspension emulsion dispersion system. Ultrasonic disperse the suspension emulsion dispersion system for 1h, then add it to a ball mill and wet mill for 60min at a grinding rate of 1600r / min, 0.6mm pure zirconia beads and 18°C ​​cooling water to prepare a 10wt% dispersion.

[0053] Preparation of low-melting antistatic nylon chips: 250g of caprolactam, 113.16g of pentamethylenediamine, 161.84g of adipic acid, 220.99g of dodecanediamine, 254.01g of dodecanediacid, 40g of dispersion, 264g of deionized water, 1g of sodium hypophosphite and 1g of antioxidant SEED were added to the polymerization kettle, replaced with nitrogen three times, and then 0.1MPa nitrogen seal was applied, and the salt was formed at 80°C for 1h, the temperature was raised to 220°C and the pressure was maintained at 0.7MPa for 2h to open the ring, and after the pressure was released to normal pressure, the temperature was raised to 250°C, vacuumed to 0.08MPa, polycondensed for 1.5h, and drawn into strips and pelletized to make low-melting antistatic nylon chips.

[0054] Preparation of low-melting-point antistatic nylon fiber: low-melting-point antistatic nylon slices are placed in a vacuum drum drying device and dried at 60°C for 4 hours, then heated to 80°C and dried for 20 hours, and the dried slices are placed in the hopper of a screw extruder, melt-extruded by the screw extruder, and then enter the spinneret assembly for spinning to form low-melting-point antistatic nylon fiber. The temperature of the first zone of the screw extruder is 220°C, the temperature of the second zone is 250°C, the temperature of the third zone is 255°C, the temperature of the composite spinning box is 260°C, the spinneret of the spinneret assembly is 36F, the side blowing cooling temperature is 20°C, the relative humidity is 60%, the GR1 temperature is 60°C, the GR2 temperature is 75°C, the winding speed is 2400m / min, the drafting multiple is 3 times, and the linear density of the low-melting-point antistatic nylon fiber is 139dtex.

[0055] Test example 1: The melting point and relative viscosity of the low-melting antistatic nylon slices prepared in Examples 1 to 3 and Comparative Examples 4 to 5 were tested. The test method was based on GB / T 38138-2019 Test Method for Fiber-Grade Polycaprolactam PA6 Slices. A differential scanning calorimeter and an Ubbelohde viscometer were used to measure the melting point and relative viscosity of the low-melting antistatic nylon slices. The test results are shown in Table 1; Table 1 Test results of low melting point antistatic nylon slices Example 1 Example Example 3 Comparative Example 4 Comparative Example 5 Melting point(℃) 115 106 97 151 190 Relative viscosity 2.654 2.562 2.738 2.776 2.686 As shown in Table 1, the melting points of the low-melting-point antistatic nylon slices prepared in Examples 1 to 3 are 97 to 115° C., and the relative viscosities are 2.562 to 2.738. The above results indicate that the low-melting-point antistatic nylon slices provided by the present invention have a low melting point; Comparative Example 4 reduces the amount of pentamethylenediamine and adipic acid, and Comparative Example 5 reduces the amount of dodecanediamine and dodecanediacid. The analysis results show that reducing the amount of pentamethylenediamine and adipic acid as well as dodecanediamine and dodecanediacid leads to a decrease in the proportion of PA56 and PA1212 generated, resulting in a rapid increase in the melting point of nylon chips.

[0056] Test Example 2: The properties of the low melting point antistatic nylon fibers prepared in Examples 1 to 3 and Comparative Examples 1 to 7 were tested, and the test methods included tensile properties, resistivity, moisture regain and water washability: The tensile properties are tested in accordance with the method disclosed in GB / T 14344-2022 Test Standard for Tensile Properties of Chemical Fiber Filaments. The tensile properties test items are breaking strength and breaking elongation. The resistivity is measured in accordance with the method disclosed in GB / T 31838-2009 Dielectric and resistance properties of solid insulating materials. The resistivity test items are volume resistivity and surface resistivity. The moisture regain is determined in accordance with the method disclosed in GB / T 6503-2017 Test method for moisture regain of chemical fibers; The washability performance was tested according to the method disclosed in "FZ / T 80007.1-2023 Test Method for Peeling Strength of Clothing Using Adhesive Interlining"; the test results are shown in Table 2; Table 2 Test results of low melting point antistatic nylon fiber As shown in Table 2, the breaking strength of the low-melting antistatic nylon fibers prepared in Examples 1 to 3 is 2.78-3.20 CN / dtex, the breaking elongation is 30-39%, the volume resistivity is 4.1E8-7.9E8 Ω·cm, the surface resistivity is 2.5E9-5.6E9 Ω, the moisture regain is 2.21-2.72%, and the average peel strength retention rate after washing is 98-99%. The above results show that the low-melting antistatic nylon fibers prepared in the present invention have excellent tensile properties, resistivity, moisture regain and water resistance.

[0057] Comparative Examples 1, 2, and 3 respectively used nano-conductive titanium dioxide, nano-aluminum-doped zinc oxide, and nano-tin dioxide as antistatic powders. The results showed that the resistivity of Comparative Examples 1, 2, and 3 was significantly lower than that of Example 1. The results show that the use of nano-antimony-doped tin oxide as antistatic powder in the present invention can make the low-melting point antistatic nylon have better antistatic properties.

[0058] In Comparative Example 4, the dosage of pentamethylenediamine and adipic acid was reduced. It was found that the moisture regain of Comparative Example 4 was lower than that of Example 1, and the surface resistivity of Comparative Example 4 was significantly higher than that of Example 1. The results show that reducing the dosage of pentamethylenediamine and adipic acid reduces the proportion of PA56 in the low-melting point antistatic nylon fiber, and the reduction in the proportion of PA56 will lead to a decrease in the moisture regain of the fiber, resulting in a significant increase in the surface resistivity of the fiber.

[0059] In Comparative Example 5, the dosage of dodecanediamine and dodecanedioic acid was reduced. It was found that the average peel strength retention rate after washing in Comparative Example 5 was significantly lower than that in Example 1. The results show that reducing the dosage of dodecanediamine and dodecanedioic acid will reduce the proportion of PA1212 in the low-melting point antistatic nylon fiber, and the reduction in the proportion of PA1212 will lead to a decrease in the water washing resistance of the fiber.

[0060] The resistivity of the fibers obtained when too much or too little antistatic powder was used in Comparative Examples 6 and 7 was significantly higher than that in Example 1. This result shows that adding a small amount or excessive amount of antistatic powder leads to a significant increase in resistivity.

[0061] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent transformation made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing low-melting-point antistatic nylon fiber, characterized in that: The following steps are involved: Nano antimony-doped tin dioxide is dispersed in water and ground to prepare a dispersion liquid; the antistatic dispersion liquid, pentamethylenediamine, adipic acid, caprolactam, dodecanediamine, dodecanediacid, an antioxidant, a catalyst, and deionized water are added into a polymerization device for polymerization reaction to prepare slices; the slices are melt-spun to prepare low-melting-point antistatic nylon fibers.

2. The preparation method according to claim 1, characterized in that: The mass of caprolactam is 250~398.8 g, the mass of pentamethylenediamine is 60.04~113.16 g, the mass of adipic acid is 85.86~161.84 g, the mass of dodecanediamine is 211.8~220.99 g, the mass of dodecanediacid is 243.5~254.01 g, and the mass of the dispersion is 7.5~33.3 g.

3. The preparation method according to claim 1, characterized in that: The particle size of the nano antimony-doped tin dioxide is 50-100 nm.

4. The preparation method according to claim 1, characterized in that: The catalyst is one or more of p-toluenesulfonic acid, sodium hydroxide, potassium hydroxide, sodium hypophosphite and zinc acetate.

5. The preparation method according to claim 1, characterized in that: The antioxidant is one or both of antioxidant 1098 and antioxidant SEED.

6. The preparation method according to claim 1 or 2, characterized in that: The concentration of the dispersion is 10-20 wt%.

7. The preparation method according to claim 1, characterized in that: The polymerization reaction conditions include: nitrogen sealing, salt formation temperature of 70-80°C, and salt formation time of 1-2 h; ring opening temperature of 220-235°C, ring opening pressure of 0.5-0.7 MPa, and pressure-maintaining ring opening time of 1-2 h; polycondensation temperature of 250-260°C, and polycondensation vacuum of 0.08-0.09 MPa.

8. The preparation method according to claim 1, characterized in that: The melt spinning conditions include: a screw temperature of 210-250°C and a spinning box temperature of 240-260°C.

9. The preparation method according to claim 1, characterized in that: The chips were vacuum dried before melt spinning.

10. The preparation method according to claim 9, characterized in that: The vacuum drying temperature is 60-80°C.

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