Enhanced polyamide 6-base parallel composite elastic fiber and preparation method thereof

Abstract

The invention relates to an enhanced polyamide 6-based parallel composite elastic fiber and a preparation method thereof. Polyether ester diol is used as a soft chain segment through a three-step melt polymerization method to prepare a PA6-based polyether ester-based thermoplastic elastomer with high viscosity, excellent mechanical properties and remarkable elasticity. And compounding the PA6-based polyether ester-based thermoplastic elastomer and PA6 in parallel, and carrying out melt spinning to obtain the PA6-based parallel composite elastic fiber with intrinsic elasticity and morphological elasticity coexisting. Compared with the prior art, the preparation process is simple, large-scale production is facilitated, the prepared PA6-based parallel composite elastic fiber is good in compatibility, remarkable in elastic effect and excellent in mechanical property, the strength can reach 3.57 cN / dtex, and the requirements of the market for functional materials and elastic fibers can be met at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of polyamide parallel composite elastic fibers, in particular to a reinforced polyamide 6-based parallel composite elastic fiber and a preparation method thereof. Background Art

[0002] From the perspective of elastic mechanism, elastic fibers can be divided into intrinsic elastic fibers and morphological elastic fibers. The preparation of intrinsic elastic fibers is to modify the materials directly by copolymerization, such as polyurethane and polyetherester fibers. These fibers are inherently elastic and durable, but it is difficult to use them alone. For example, spandex often needs to be processed again with other fibers before it can be woven on a machine. The preparation of morphological elastic fibers is to change the spinning process during the spinning process to intervene and regulate the fiber structure and appearance. In the preparation method of morphological elasticity, parallel composite spinning is expected to achieve independent use of elastic fibers by changing the composite components. At present, this research direction is mostly focused on polyester materials, such as T400, T800 and other two-component parallel fibers, but polyester fibers have poor moisture absorption and air permeability and are difficult to dye. As the excellent comprehensive performance of polyamide brings comfort to polyamide fibers, it is gradually favored by consumers. We find that various types of modification research on polyamide fibers have broad commercial value.

[0003] At present, there is relatively little research on the parallel composite elastic fibers of polyamide 6 (PA6). Based on the parallel composite yarn of PA6 and PA-based thermoplastic elastomer TPA6510, the TPA6510 elastomer soft segment used is polyether, and the strength of the elastic fiber obtained is only 1.4cN / dtex, which is difficult to meet the wearing requirements. This may be due to the low strength of TPA6510 itself. Based on PA6 / TPAE6 parallel composite fibers, the TPAE6 used is a copolymer of PA6, PPG and PE. The strength of the parallel yarn can only reach 2.14cN / dtex, and the elastic recovery rate drops significantly after five stretching cycles. The durability needs to be optimized. This may be due to the poor performance of TPAE6 caused by the PPG and PEG soft segments, and the better combination effect cannot be exerted after parallel spinning. Therefore, inventing a PA6-based parallel composite elastic fiber with higher strength and excellent elasticity is an effective way to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a reinforced polyamide 6-based parallel composite elastic fiber and a preparation method thereof in order to overcome the defects of the above-mentioned prior art. The prepared parallel composite elastic fiber has higher strength and excellent elasticity.

[0005] The conceptual process of the present application is as follows: the present invention selects a polyether ester diol which does not crystallize at room temperature and contains benzene rings as a soft segment and prepares a PA6-based polyether ester-based thermoplastic elastomer with high viscosity, excellent mechanical properties and significant elasticity through a three-step melt polymerization method, and then the PA6-based polyether ester-based thermoplastic elastomer is compounded with PA6 in parallel and melt-spun to obtain an elastic fiber with coexistence of intrinsic elasticity and morphological elasticity. At the same time, the preparation process is simplified to achieve large-scale preparation.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] In one aspect, the present invention provides a method for preparing a reinforced polyamide 6-based parallel composite elastic fiber, characterized in that it comprises the following steps:

[0008] S1. Add caprolactam, deionized water, end-capping agent, ring-opening agent and thermal stabilizer into a reaction vessel and stir evenly. After nitrogen is introduced to replace the air in the reactor, the pressure is increased to 2-3 bar. At a stirring speed of 80-120 r / min, the temperature is increased to 240-260° C., and after reacting for 2 hours, the pressure is reduced to 5000 Pa, and the reaction is continued for 1-2 hours to obtain a double-terminal carboxyl PA6 prepolymer.

[0009] S2. Add diol to the double-terminated carboxyl PA6 prepolymer obtained in S1 under normal pressure, control the temperature at 240-260°C, introduce nitrogen to replace the air in the reactor, pressurize to 2-3 bar, control the pressure at 2-8 bar during the reaction, stir at 80-120 r / min, and continue the reaction for 1-2 h;

[0010] S3, under normal pressure, adding polyether ester diol and ester exchange catalyst to the mixture of S2, introducing nitrogen to replace the air in the reactor, reacting at 240°C and a stirring speed of 80-120 r / min for 1-2 hours, then gradually reducing the pressure to 20-100 Pa, raising the temperature to 260-280°C, continuing the polycondensation reaction for 1-4 hours, and drying to obtain a PA6-based polyether ester-based elastomer;

[0011] S4, melt-spinning the PA6-based polyetherester-based elastomer and PA6 prepared in S3 in parallel to obtain a reinforced PA6-based parallel composite elastic fiber.

[0012] Furthermore, in S1, the mass ratio of the caprolactam, deionized water, end-capping agent, ring-opening agent and thermal stabilizer is 100:5:(5-6):(1-10):(0.1-4).

[0013] Preferably, in S1, the mass ratio of the caprolactam, deionized water, end-capping agent, ring-opening agent and thermal stabilizer is 100:5:(5-6):(1-2):(0.1-0.2).

[0014] Furthermore, in S1, the end-capping agent is any one of terephthalic acid (PTA), isophthalic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, and adipic acid.

[0015] Furthermore, in S1, the auxiliary ring-opening agent is any one of 5-aminopentanoic acid, 6-aminohexanoic acid, 7-aminoheptanoic acid, and 8-aminooctanoic acid.

[0016] Furthermore, in S1, the heat stabilizer is any one of Irganox 1010, Irganox 168, triphenyl phosphate, and triphenyl phosphite.

[0017] Furthermore, in S2, the diol is any one of ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol.

[0018] Furthermore, in S3, the mass ratio of the polyether ester diol to the ester exchange catalyst is (30-65): (0.1-0.17).

[0019] Preferably, in S3, the mass ratio of the polyether ester diol to the ester exchange catalyst is (40-65): (0.1-0.17).

[0020] Furthermore, in S3, the transesterification catalyst is any one of anhydrous zinc acetate, tetrabutyl titanate, isopropyl titanate, manganese acetate, antimony acetate, magnesium acetate, and antimony trioxide.

[0021] Furthermore, in S3, the polyether ester diol is a regenerated polyether ester diol, and the molecular weight of the regenerated polyether ester diol is 500 to 3000 g / mol.

[0022] Preferably, in S3, the molecular weight of the regenerated polyetherester diol is 1200 g / mol.

[0023] Preferably, in S4, the mass ratio of the PA6-based polyetherester-based elastomer to PA6 is 1:(1-4).

[0024] Furthermore, in S4, the mass ratio of the PA6-based polyetherester-based elastomer to PA6 is 1:(3-4).

[0025] On the other hand, the present invention also provides a reinforced polyamide 6-based parallel composite elastic fiber, which is prepared by the above method.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The present invention uses PA6 as one component of the parallel composite elastic fiber and PA6-based polyether ester-based elastomer as the other component, and obtains the PA6-based polyether ester-based elastomer by a three-step melt polymerization method. The obtained elastomer has high polymerization efficiency and does not need to strictly control the molar ratio of each reactant. The incorporation of a diol intermediate can achieve an equal stoichiometric ratio of each functional group in the reaction system. The process route is simple and the reaction time is short. Then, by parallel composite melt spinning, a composite elastic fiber with good compatibility, significant elastic effect and excellent mechanical properties is obtained. The strength can be as high as 3.57 cN / dtex, achieving the coexistence of intrinsic elasticity and morphological elasticity.

[0028] (2) The two components of the parallel composite elastic fiber prepared by the present invention are both polyamides, so that the two components have good interface compatibility and ensure good interface adhesion between the two components; at the same time, the elastic performance and mechanical properties of the PA6-based polyetherester-based thermoplastic elastomer are better than those of the representative polyamide thermoplastic elastomer in the industry after testing. (The tensile strength and elongation at break are 20MPa and 500% respectively); the mechanical properties and elasticity of the PA6-based parallel composite elastic fiber prepared by the present invention are significantly better than the existing PA6-based parallel elastic fiber and the commercially successful T400 elastic filament. In summary, the material system of the present invention has low cost, simple process flow, and excellent product performance, which can meet the market demand for functional materials and elastic fibers at the same time. DETAILED DESCRIPTION

[0029] The present invention is described in detail below in conjunction with specific embodiments. Any features such as preparation means, materials, structures or composition ratios not clearly described in this technical solution are regarded as common technical features disclosed in the prior art.

[0030] The raw materials in the following examples are as follows, but are not limited to the following raw materials. The following raw materials are only used as specific examples to illustrate the effects of PA6-based parallel composite elastic fibers.

[0031] The detection method of the performance parameters involved in the present invention is as follows:

[0032] (1) Relative viscosity of PA6-based polyetherester elastomer: Determine the outflow time of a sample solution containing (90.00±0.15)% formic acid and a concentration of 0.005 g / mL under the action of gravity at (25.00±0.02)°C. Calculate the relative viscosity based on the measured outflow time. For specific test principles and methods, see GB / T12006.1-2009.

[0033] Tensile strength: GB / T 1040-2006;

[0034] Elongation at break: GB / T 1040-2006;

[0035] Notched impact strength: GB / T 1843-2008;

[0036] Shore hardness: GB / T 2411-2008.

[0037] (2) Linear density of PA6-based parallel composite elastic fiber: The test method of linear density can refer to GB / T 14343-2008 Test method for linear density of chemical fiber filaments. A YG086 yarn length measuring instrument is used. The circumference of the yarn frame is (1.000±0.002) m. The length and mass of each sample are collected respectively. The length is obtained by multiplying the number of turns by the length of the yarn frame. The sample is weighed after debugging in standard atmosphere, accurate to 1 mg. Each sample is tested 10 times and the average value is calculated.

[0038] Strength: Under standard atmospheric conditions, use a constant rate elongation tester and calculate the strength according to the formula Calculate its strength, where σ is the breaking strength, in centinewtons per dtex (cN / dtex); F is the breaking strength of the sample, in centinewtons (cN); T is the linear density measured by the same laboratory sample, in dtex (dtex). For specific test principles and methods, see GB / T14344-2008.

[0039] Elongation at break: Under standard atmospheric conditions, using a constant rate elongation tester, according to the formula Calculate its elongation, where ε is the elongation at break, %; E is the elongation value, in millimeters (mm); L0 is the starting length, in millimeters (mm). For specific test principles and methods, see GB / T14344-2008.

[0040] Elastic recovery rate: The fixed-cycle tensile test of elastic fibers was carried out on a YG061 electronic single yarn strength tester.

[0041] A method for preparing a reinforced polyamide 6-based parallel composite elastic fiber of the present invention comprises the following steps:

[0042] S1. Add caprolactam, deionized water, end-capping agent, ring-opening agent and thermal stabilizer into a reaction vessel and stir evenly. After nitrogen is introduced to replace the air in the reactor, the pressure is increased to 2-3 bar. At a stirring speed of 80-120 r / min, the temperature is increased to 240-260° C., and after reacting for 2 hours, the pressure is reduced to 5000 Pa, and the reaction is continued for 1-2 hours to obtain a double-terminal carboxyl polyamide 6 prepolymer.

[0043] S2. Add diol to the double-terminal carboxyl polyamide 6 prepolymer prepared in S1 under normal pressure, control the temperature at 240-260°C, introduce nitrogen to replace the air in the reactor, pressurize to 2-3 bar, control the pressure at 2-8 bar during the reaction, stir at 80-120 r / min, and continue the reaction for 1-2 h;

[0044] S3. Add polyether ester diol and transesterification catalyst to the mixture of S2 under normal pressure, introduce nitrogen to replace the air in the reactor, react for 1 to 2 hours at 240°C and a stirring speed of 80 to 120 r / min, then gradually reduce the pressure to 20 to 100 Pa, raise the temperature to 260 to 280°C, continue the polycondensation reaction for 1 to 4 hours, and dry to obtain a polyamide 6-based polyether ester-based elastomer, the general structure of which is as follows:

[0045]

[0046] Among them, the soft segment The hard segment is a carboxyl-terminated PA6 prepolymer, and the molecular weight of the PA6 prepolymer is controlled to be 3000 g / mol by adjusting the dosage relationship between the end-capping agent dibasic acid and caprolactam; the soft segment is a polyether ester diol, and the molecular weight is 1200 g / mol; it should be additionally explained that in the above formula, the double slash between the hard segment and the soft segment indicates that the two components are composed of blocks.

[0047] S4, melt-spinning the polyamide 6-based polyetherester-based elastomer and polyamide 6 obtained in S3 in parallel to obtain a reinforced polyamide 6-based parallel composite elastic fiber.

[0048] Example 1

[0049] The present invention provides a method for preparing a reinforced polyamide 6-based parallel composite elastic fiber, comprising the following steps:

[0050] S1. Add 100g caprolactam, 5g deionized water, 5.8g PTA, 2g 6-aminocaproic acid and 0.2g Irganox168 into a reaction vessel, introduce nitrogen to replace the air in the reactor, pressurize to 2.3bar, raise the temperature to 240°C at a stirring speed of 120r / min, react for 2h, reduce the pressure to 5000Pa, continue to react for 1h, and the obtained double-terminal carboxyl PA6 prepolymer is left in the polymerization kettle for the next step of reaction;

[0051] S2. After the first step of the reaction is completed, the pressure is released to normal pressure, 10 g of ethylene glycol is added to the polymerization kettle through the secondary feeding device, the temperature is controlled at 240 ° C, nitrogen is introduced to replace the air in the reactor, and the pressure is increased to 3 bar. During the reaction, the pressure is controlled at 2 to 8 bar, the stirring speed is 120 r / min, and the reaction is continued for 2 hours;

[0052] S3, after the second step reaction is completed, the pressure is released to normal pressure, 40g of regenerated polyether ester diol and 0.01g of anhydrous zinc acetate are added to the mixture of S2, nitrogen is introduced to replace the air in the reactor, and the reaction is carried out at 240°C and a stirring speed of 120r / min for 1h, and then the pressure is gradually reduced to 50Pa, the temperature is raised to 260°C, and the polycondensation reaction is continued for 2h to obtain a polymer. After drying, a PA6-based polyether ester-based elastomer of the recycled raw material polyether ester soft segment is obtained. The tensile strength of the elastomer is 41MPa, the elongation at break is 670%, and the notched impact strength is 36KJ / m 2 , Shore hardness is 58D, relative viscosity is 2.3;

[0053] S4. PA6 and the PA6-based polyether ester-based elastomer prepared in S3 are melt-spun in parallel at a composite ratio of 3:1, wherein the viscosity of the PA6-based polyether ester-based elastomer is 2.3, and the viscosity of PA6 is 2.45. The linear density of the obtained reinforced PA6-based parallel composite elastic fiber is 44.1 dtex, the strength is 3.57 cN / dtex, the elongation at break is 26%, and the elastic recovery rate is 100% at a fixed elongation of 20%.

[0054] Example 2

[0055] The present invention provides a method for preparing a reinforced polyamide 6-based parallel composite elastic fiber, comprising the following steps:

[0056] S1. Add 100g caprolactam, 5g deionized water, 5.8g PTA, 2g 6-aminocaproic acid and 0.2g Irganox168 into a reaction vessel, introduce nitrogen to replace the air in the reactor, pressurize to 2.3bar, raise the temperature to 240°C at a stirring speed of 120r / min, react for 2h, reduce the pressure to 5000Pa, continue to react for 1h, and the obtained double-terminal carboxyl PA6 prepolymer is left in the polymerization kettle for the next step of reaction;

[0057] S2. After the first step of the reaction is completed, the pressure is released to normal pressure, 10 g of ethylene glycol is added to the polymerization kettle through the secondary feeding device, the temperature is controlled at 240 ° C, nitrogen is introduced to replace the air in the reactor, and the pressure is increased to 3 bar. During the reaction, the pressure is controlled at 2 to 8 bar, the stirring speed is 120 r / min, and the reaction is continued for 2 hours;

[0058] S3, after the second step reaction is completed, the pressure is released to normal pressure, 40g of regenerated polyether ester diol and 0.121g of anhydrous zinc acetate are added to the mixture of S2, nitrogen is introduced to replace the air in the reactor, and the mixture is reacted at 240°C and a stirring speed of 120r / min for 1h, and then the pressure is gradually reduced to 50Pa, the temperature is raised to 260°C, and the polycondensation reaction is continued for 2h to obtain a polymer. After drying, a PA6-based polyether ester-based elastomer of the recycled raw material polyether ester soft segment is obtained. The tensile strength of the elastomer is 49MPa, the elongation at break is 474%, and the notched impact strength is 34KJ / m 2 , Shore hardness is 61D, relative viscosity is 2.29;

[0059] S4, PA6 and the PA6-based polyether ester-based elastomer prepared in S3 are melt-spun in parallel at a composite ratio of 3:1, wherein the viscosity of the PA6-based polyether ester-based elastomer is 2.29, and the viscosity of PA6 is 2.8. The obtained reinforced PA6-based parallel composite elastic fiber has a linear density of 50 dtex, a strength of 3.41 cN / dtex, an elongation at break of 31%, and an elastic recovery rate of 94% after ten cycles of a fixed elongation of 20%.

[0060] Example 3

[0061] The present invention provides a method for preparing a reinforced polyamide 6-based parallel composite elastic fiber, comprising the following steps:

[0062] S1. Add 100g caprolactam, 5g deionized water, 5.8g PTA, 2g 6-aminocaproic acid and 0.2g Irganox168 into a reaction vessel, introduce nitrogen to replace the air in the reactor, pressurize to 3 bar, raise the temperature to 240°C at a stirring speed of 120r / min, react for 2h, reduce the pressure to 5000Pa, continue to react for 1h, and the obtained double-terminal carboxyl PA6 prepolymer is left in the polymerization kettle for the next step of reaction;

[0063] S2. After the first step of the reaction is completed, the pressure is released to normal pressure, 9 g of ethylene glycol is added to the polymerization kettle through the secondary feeding device, the temperature is controlled at 240 ° C, nitrogen is introduced to replace the air in the reactor, and the pressure is increased to 3 bar. During the reaction, the pressure is controlled at 2 to 8 bar, the stirring speed is 120 r / min, and the reaction is continued for 2 hours;

[0064] S3, after the second step reaction is completed, the pressure is released to normal pressure, 50g of regenerated polyether ester diol and 0.137g of anhydrous zinc acetate are added to the mixture of S2, nitrogen is introduced to replace the air in the reactor, and the mixture is reacted at 240°C and a stirring speed of 120r / min for 1h, and then the pressure is gradually reduced to 100Pa, the temperature is raised to 260°C, and the polycondensation reaction is continued for 3.5h to obtain a polymer, and after drying, a PA6-based polyether ester-based elastomer of the recycled raw material polyether ester soft segment is obtained. The tensile strength of the elastomer is 47MPa, the elongation at break is 544%, and the notched impact strength is 53KJ / m 2 , Shore hardness is 51D, relative viscosity is 2.25;

[0065] S4, PA6 and the PA6-based polyether ester-based elastomer prepared in S3 are melt-spun in parallel at a composite ratio of 4:1, wherein the viscosity of the PA6-based polyether ester-based elastomer is 2.25, and the viscosity of PA6 is 2.6. The linear density of the obtained reinforced PA6-based parallel composite elastic fiber is 50.8 dtex, the strength is 3.48 cN / dtex, the elongation at break is 46%, and the elastic recovery rate is still 92% after ten cycles of fixed elongation of 15%.

[0066] Example 4

[0067] The present invention provides a method for preparing a reinforced polyamide 6-based parallel composite elastic fiber, comprising the following steps:

[0068] S1. Add 100g caprolactam, 5g deionized water, 5.8g PTA, 2g 6-aminocaproic acid and 0.2g Irganox1010 into a reaction vessel, introduce nitrogen to replace the air in the reactor, pressurize to 2.5bar, raise the temperature to 240°C at a stirring speed of 120r / min, react for 2h, reduce the pressure to 5000Pa, continue to react for 1h, and the obtained double-terminal carboxyl PA6 prepolymer is left in the polymerization kettle for the next step of reaction;

[0069] S2. After the first step of the reaction is completed, the pressure is released to normal pressure, 12 g of ethylene glycol is added to the polymerization kettle through the secondary feeding device, the temperature is controlled at 240 ° C, nitrogen is introduced to replace the air in the reactor, and the pressure is increased to 3 bar. During the reaction, the pressure is controlled at 2 to 8 bar, the stirring speed is 120 r / min, and the reaction is continued for 2 hours;

[0070] S3, after the second step reaction is completed, the pressure is released to normal pressure, 60g of regenerated polyether ester diol and 0.145g of tetrabutyl titanate are added to the mixture of S2, nitrogen is introduced to replace the air in the reactor, and the reaction is carried out at 240°C and a stirring speed of 120r / min for 1h, and then the pressure is gradually reduced to 20Pa, the temperature is raised to 260°C, and the polycondensation reaction is continued for 3.5h to obtain a polymer, and after drying, a PA6-based polyether ester-based elastomer of the recycled raw material polyether ester soft segment is obtained. The tensile strength of the elastomer is 43MPa, the elongation at break is 758%, and the notched impact strength is 65KJ / m 2 , Shore hardness is 48D, relative viscosity is 2.33;

[0071] S4. PA6 and the PA6-based polyether ester-based elastomer prepared in S3 are melt-spun in parallel at a composite ratio of 3:1, wherein the viscosity of the PA6-based polyether ester-based elastomer is 2.33, and the viscosity of PA6 is 2.75. The linear density of the obtained reinforced PA6-based parallel composite elastic fiber is 45.1 dtex, the strength is 3.51 cN / dtex, the elongation at break is 28%, and the elastic recovery rate at a fixed elongation of 5% is 98%.

[0072] Example 5

[0073] The present invention provides a method for preparing a reinforced polyamide 6-based parallel composite elastic fiber, comprising the following steps:

[0074] S1. Add 100g caprolactam, 5g deionized water, 5.8g PTA, 2g 8-aminocaprylic acid and 0.2g triphenyl phosphate into a reaction vessel, introduce nitrogen to replace the air in the reactor, pressurize to 2.5bar, raise the temperature to 240°C at a stirring speed of 120r / min, react for 2h, reduce the pressure to 5000Pa, continue to react for 1h, and the obtained double-terminated carboxyl PA6 prepolymer is left in the polymerization kettle for the next step of reaction;

[0075] S2. After the first step of the reaction is completed, the pressure is released to normal pressure, 12 g of ethylene glycol is added to the polymerization kettle through the secondary feeding device, the temperature is controlled at 240 ° C, nitrogen is introduced to replace the air in the reactor, and the pressure is increased to 3 bar. During the reaction, the pressure is controlled at 2 to 8 bar, the stirring speed is 120 r / min, and the reaction is continued for 2 hours;

[0076] S3, after the second step reaction is completed, the pressure is released to normal pressure, 65g of regenerated polyether ester diol and 0.149g of anhydrous zinc acetate are added to the mixture of S2, nitrogen is introduced to replace the air in the reactor, and the reaction is carried out at 240°C and a stirring speed of 120r / min for 1h, and then the pressure is gradually reduced to 100Pa, the temperature is raised to 260°C, and the polycondensation reaction is continued for 2.5h to obtain a polymer, and after drying, a PA6-based polyether ester-based elastomer of the recycled raw material polyether ester soft segment is obtained. The tensile strength of the elastomer is 41MPa, the elongation at break is 750%, and the notched impact strength is 74KJ / m 2 , Shore hardness is 42D, relative viscosity is 2.4;

[0077] S4. PA6 and the PA6-based polyether ester-based elastomer prepared by S3 are melt-spun in parallel at a composite ratio of 4:1, wherein the viscosity of the PA6-based polyether ester-based elastomer is 2.4, and the viscosity of PA6 is 2.8. The linear density of the obtained reinforced PA6-based parallel composite elastic fiber is 49.1dtex, the strength is 3.32cN / dtex, the elongation at break is 35%, the elastic recovery rate is still 93% after ten cycles with a fixed elongation of 15%, and the elastic recovery rate is still 90% after ten cycles with a fixed elongation of 20%.

[0078] Example 6

[0079] The present invention provides a method for preparing a reinforced polyamide 6-based parallel composite elastic fiber, comprising the following steps:

[0080] S1. Add 90g of caprolactam, 4.5g of deionized water, 5.3g of PTA, 1.5g of 6-aminoacetic acid and 0.15g of Irganox168 into a reaction vessel, introduce nitrogen to replace the air in the reactor, pressurize to 2.5 bar, heat to 240° C. at a stirring speed of 120 r / min, react for 2h, then reduce the pressure to 5000 Pa, continue to react for 1h, and the obtained double-terminated carboxyl PA6 prepolymer is left in the polymerization vessel for the next step of reaction;

[0081] S2. After the first step of the reaction is completed, the pressure is released to normal pressure, 12 g of ethylene glycol is added to the polymerization kettle through the secondary feeding device, the temperature is controlled at 240 ° C, nitrogen is introduced to replace the air in the reactor, and the pressure is increased to 3 bar. During the reaction, the pressure is controlled at 2 to 8 bar, the stirring speed is 120 r / min, and the reaction is continued for 2 hours;

[0082] S3, after the second step reaction is completed, the pressure is released to normal pressure, 49.5g of regenerated polyether ester diol and 0.161g of anhydrous zinc acetate are added to the mixture of S2, nitrogen is introduced to replace the air in the reactor, and the mixture is reacted at 240°C and a stirring speed of 120r / min for 1h, and then the pressure is gradually reduced to 100Pa, the temperature is raised to 260°C, and the polycondensation reaction is continued for 2h to obtain a polymer. After drying, a PA6-based polyether ester-based elastomer of the recycled raw material polyether ester soft segment is obtained. The tensile strength of the elastomer is 39MPa, the elongation at break is 628%, and the notched impact strength is 49KJ / m 2 , Shore hardness is 49D, relative viscosity is 2.35;

[0083] S4. PA6 and the PA6-based polyether ester-based elastomer prepared in S3 are melt-spun in parallel at a composite ratio of 4:1, wherein the viscosity of the PA6-based polyether ester-based elastomer is 2.35, and the viscosity of PA6 is 2.45. The linear density of the obtained reinforced PA6-based parallel composite elastic fiber is 43.4 dtex, the strength is 3.54 cN / dtex, the elongation at break is 24%, and the elastic recovery rate at a fixed elongation of 5% is 97%.

[0084] Comparative Example 1

[0085] Representative polyamide thermoplastic elastomers in the industry The tensile strength and elongation at break are 20 MPa and 500% respectively. Compared with the tensile strength and elongation at break of the polyamide-based thermoplastic elastomer, the mechanical properties of the polyamide-based thermoplastic elastomer are more excellent.

[0086] The strength of the existing PA6 series parallel elastic filaments PA6 / TPAE parallel composite fibers is 2.14 cN / dtex, the strength of the PA6 / TPA6510 parallel composite fibers is 1.4 cN / dtex, and the strength of the PA6 / PBTE parallel fibers is 2.4 cN / dtex, indicating that the parallel elastic fibers of the present invention have significant advantages in strength; the breaking strength of the commercial parallel yarn T400 is 2.44 cN / dtex, and the breaking elongation is 21%. It can be seen that the elastic filaments of the present invention are superior to T400 in both breaking strength and elongation.

[0087] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for preparing a reinforced polyamide 6-based parallel composite elastic fiber, characterized in that: The following steps are involved: S1, caprolactam, deionized water, end-capping agent, ring-opening agent and thermal stabilizer are uniformly stirred to obtain a double-terminated carboxyl polyamide 6 prepolymer; S2, mixing the double-terminated carboxyl polyamide 6 prepolymer prepared in S1 with a diol for reaction; S3, adding polyether ester diol and transesterification catalyst to the mixture of S2, stirring and mixing, to prepare polyamide 6-based polyether ester-based elastomer; S4, melt-spinning the polyamide 6-based polyetherester-based elastomer and polyamide 6 obtained in S3 in parallel to obtain a reinforced polyamide 6-based parallel composite elastic fiber.

2. The method for preparing a reinforced polyamide 6-based parallel composite elastic fiber according to claim 1, characterized in that: In S1, the mass ratio of caprolactam, deionized water, end-capping agent, ring-opening agent and thermal stabilizer is 100:5:(5-6):(1-10):(0.1-4).

3. The method for preparing a reinforced polyamide 6-based parallel composite elastic fiber according to claim 1, characterized in that: In S1, the end-capping agent is any one of terephthalic acid, isophthalic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, and adipic acid.

4. The method for preparing a reinforced polyamide 6-based parallel composite elastic fiber according to claim 1, characterized in that: In S1, the auxiliary ring-opening agent is any one of 5-aminopentanoic acid, 6-aminohexanoic acid, 7-aminoheptanoic acid, and 8-aminooctanoic acid.

5. The method for preparing a reinforced polyamide 6-based parallel composite elastic fiber according to claim 1, characterized in that: In S1, the heat stabilizer is any one of Irganox 1010, Irganox 168, triphenyl phosphate, and triphenyl phosphite.

6. The method for preparing a reinforced polyamide 6-based parallel composite elastic fiber according to claim 1, characterized in that: In S2, the diol is any one of ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol.

7. The method for preparing a reinforced polyamide 6-based parallel composite elastic fiber according to claim 1, characterized in that: In S3, the mass ratio of the polyether ester diol to the ester exchange catalyst is (30-65): (0.1-0.17).

8. The method for preparing a reinforced polyamide 6-based parallel composite elastic fiber according to claim 1, characterized in that: In S3, the transesterification catalyst is any one of anhydrous zinc acetate, tetrabutyl titanate, isopropyl titanate, manganese acetate, antimony acetate, magnesium acetate, and antimony trioxide, and the molecular weight of the polyether ester diol is 500 to 3000 g / mol.

9. The method for preparing a reinforced polyamide 6-based parallel composite elastic fiber according to claim 1, characterized in that: In S4, the mass ratio of the polyamide 6-based polyetherester-based elastomer to polyamide 6 is 1:(1-4).

10. A reinforced polyamide 6-based parallel composite elastic fiber prepared by the method according to any one of claims 1 to 9.

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