A reinforced polyamide 6-based parallel composite elastic fiber and its preparation method

Abstract

The present invention relates to a reinforced polyamide 6-based parallel composite elastic fiber and a preparation method thereof. The present invention utilizes a three-step melt polymerization method to prepare a PA6-based polyetherester-based thermoplastic elastomer with high viscosity, excellent mechanical properties, and significant elasticity using a polyetherester diol as a soft segment. The PA6-based polyetherester-based thermoplastic elastomer is then composited with PA6 in parallel and melt-spun to produce a PA6-based parallel composite elastic fiber exhibiting both intrinsic and morphological elasticity. Compared to existing technologies, the present invention offers a simpler preparation process and facilitates large-scale production. The resulting PA6-based parallel composite elastic fiber exhibits good compatibility, significant elasticity, and excellent mechanical properties, with a strength of up to 3.57 cN / dtex, meeting market demand for both functionalized materials and elastic fibers.

Description

Technical Field

[0001] The present 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] Based on their elasticity mechanisms, elastic fibers can be categorized as intrinsically elastic and morphologically elastic. Intrinsically elastic fibers, such as polyurethane and polyetherester fibers, are prepared by direct material modification through copolymerization. These fibers possess inherent elasticity and durability, but are difficult to use independently. For example, spandex often requires further processing with other fibers before it can be woven. Morphologically elastic fibers are prepared by modifying the spinning process during the spinning process to manipulate the fiber structure and appearance. Among morphologically elastic preparation methods, parallel composite spinning offers the potential to achieve independent use of elastic fibers by varying the composite components. Currently, this research focus is primarily on polyester materials, such as bicomponent parallel fibers like T400 and T800. However, polyester fibers exhibit poor moisture absorption and breathability, making them difficult to dye. As the superior overall performance of polyamide fibers, coupled with the comfort they provide, continues to gain consumer favor, we believe that research on various types of polyamide fiber modifications holds broad commercial value.

[0003] Currently, there is relatively little research on polyamide 6 (PA6) parallel composite elastic fibers. For parallel composite yarns based on PA6 and the PA-based thermoplastic elastomer TPA6510, the TPA6510 elastomer soft segment used is polyether, and the resulting elastic fiber strength only reaches 1.4 cN / dtex, which is difficult to meet the requirements for wear. This may be due to the low strength of TPA6510 itself. For 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 2.14 cN / 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 due to the PPG and PEG soft segments, and the failure to achieve a better combination effect 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 overcome the defects of the above-mentioned prior art and to provide a reinforced polyamide 6-based parallel composite elastic fiber and a preparation method thereof. The prepared parallel composite elastic fiber has higher strength and excellent elasticity.

[0005] The conception process of this application is as follows: the present invention selects a polyether ester diol that 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. The PA6-based polyether ester-based thermoplastic elastomer is then 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, and large-scale preparation can be achieved.

[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 to 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 raised to 240-260° C., and the reaction is carried out for 2 hours. The pressure is then reduced to 5000 Pa and the reaction is continued for 1-2 hours to obtain a double-end carboxyl PA6 prepolymer.

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

[0010] S3. Add polyetherester diol and transesterification catalyst to the mixture of S2 under normal pressure, introduce nitrogen to replace the air in the reactor, react at 240° C. and a stirring speed of 80-120 r / min for 1-2 hours, then gradually reduce the pressure to 20-100 Pa, increase the temperature to 260-280° C., continue the polycondensation reaction for 1-4 hours, and dry to obtain a PA6-based polyetherester-based elastomer;

[0011] S4. Melt-spinning the PA6-based polyetherester-based elastomer and PA6 prepared in S3 in parallel to obtain reinforced PA6-based parallel composite elastic fibers.

[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 thermal 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 polyetherester diol to the ester exchange catalyst is (30-65): (0.1-0.17).

[0019] Preferably, in S3, the mass ratio of the polyetherester 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 polyetherester diol is a recycled polyetherester diol, and the molecular weight of the recycled polyetherester 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 polyetherester-based elastomer as the other component, and prepares the PA6-based polyetherester-based elastomer through a three-step melt polymerization method. The polymerization efficiency of the prepared elastomer is high, and there is no 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, through parallel composite melt spinning, a composite elastic fiber with good compatibility, significant elastic effect and excellent mechanical properties is obtained, and 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, which makes the two components have good interface compatibility and ensures 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 20 MPa and 500%, respectively). The PA6-based parallel composite elastic fiber produced by the present invention exhibits significantly better mechanical properties and elasticity than existing PA6-based parallel elastic fibers and the commercially successful T400 elastic filament. In summary, the present material system offers low cost, a simple process flow, and excellent product performance, meeting market demand for both functional materials and elastic fibers. DETAILED DESCRIPTION

[0029] The present invention will be described in detail below with reference to specific embodiments. Any features such as preparation methods, materials, structures or composition ratios not explicitly described in this technical solution are considered to be 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 raw materials described below. The following raw materials are 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 efflux time of a sample solution containing (90.00±0.15)% formic acid and a concentration of 0.005 g / mL at (25.00±0.02)°C under gravity. Calculate the relative viscosity based on the measured efflux 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, and the circumference of the yarn frame is (1.000±0.002)m. The length and mass of each sample are collected separately. The length is calculated by multiplying the number of turns by the yarn frame length. The sample is weighed after debugging in standard atmosphere, with an accuracy of 1mg. 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 decitex (cN / dtex); F is the breaking strength of the specimen in centinewtons (cN); and T is the linear density of the sample measured in the same laboratory in decitex (dtex). For specific test principles and methods, see GB / T14344-2008.

[0039] Elongation at break: Under standard atmospheric conditions, use a constant rate elongation tester and calculate the elongation at break according to the formula Calculate the elongation, where ε is the elongation at break (%), E is the elongation value (mm), and L0 is the starting length (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] The present invention provides a method for preparing a reinforced polyamide 6-based parallel composite elastic fiber, comprising 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 raised 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-end carboxyl polyamide 6 prepolymer;

[0043] S2. Add diol to the double-end 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, and then pressurize to 2-3 bar. During the reaction, control the pressure at 2-8 bar, stir at 80-120 r / min, and continue the reaction for 1-2 h.

[0044] S3. Under normal pressure, add polyether ester diol and transesterification catalyst to the mixture of S2, introduce nitrogen to replace the air in the reactor, react at 240°C and a stirring speed of 80-120 r / min for 1-2 hours, then gradually reduce the pressure to 20-100 Pa, increase the temperature to 260-280°C, continue the polycondensation reaction for 1-4 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 carboxylated PA6 prepolymer. The molecular weight of the PA6 prepolymer is controlled to 3000 g / mol by regulating the amount of the end-capping agent dibasic acid and caprolactam. The soft segment is a polyetherester diol with a molecular weight of 1200 g / mol. It should be additionally noted 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 prepared 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 100 g of caprolactam, 5 g of deionized water, 5.8 g of PTA, 2 g of 6-aminocaproic acid, and 0.2 g of Irganox168 to a reaction vessel. After nitrogen is introduced to replace the air in the reactor, the pressure is increased to 2.3 bar. At a stirring speed of 120 r / min, the temperature is raised to 240° C., and the reaction is carried out for 2 h. The pressure is then reduced to 5000 Pa and the reaction is continued for 1 h. The obtained double-end carboxyl PA6 prepolymer is left in the polymerization vessel for the next 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 h;

[0052] S3. After the second step of the 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 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 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 polyetherester-based elastomer prepared in S3 are melt-spun in parallel at a composite ratio of 3:1, wherein the viscosity of the PA6-based polyetherester-based elastomer is 2.3, and the viscosity of PA6 is 2.45. The obtained reinforced PA6-based parallel composite elastic fiber has a linear density of 44.1 dtex, a strength of 3.57 cN / dtex, an elongation at break of 26%, and an elastic recovery rate of 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 100 g of caprolactam, 5 g of deionized water, 5.8 g of PTA, 2 g of 6-aminocaproic acid, and 0.2 g of Irganox168 to a reaction vessel. After nitrogen is introduced to replace the air in the reactor, the pressure is increased to 2.3 bar. At a stirring speed of 120 r / min, the temperature is raised to 240° C., and the reaction is carried out for 2 h. The pressure is then reduced to 5000 Pa and the reaction is continued for 1 h. The obtained double-end carboxyl PA6 prepolymer is left in the polymerization vessel for the next 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 h;

[0058] S3. After the second step of the 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 polyetherester-based elastomer prepared in S3 are melt-spun in parallel at a composite ratio of 3:1, wherein the viscosity of the PA6-based polyetherester-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 100 g of caprolactam, 5 g of deionized water, 5.8 g of PTA, 2 g of 6-aminocaproic acid, and 0.2 g of Irganox168 to a reaction vessel. After nitrogen is introduced to replace the air in the reactor, the pressure is increased to 3 bar. At a stirring speed of 120 r / min, the temperature is raised to 240° C., and the reaction is carried out for 2 h. The pressure is then reduced to 5000 Pa and the reaction is continued for 1 h. The obtained double-end carboxyl PA6 prepolymer is left in the polymerization vessel for the next reaction.

[0063] S2. After the first step of the reaction is completed, the pressure is released to normal pressure, and 9 g of ethylene glycol is added to the polymerization kettle through the secondary feeding device. The temperature is controlled at 240 ° C. After nitrogen is introduced to replace the air in the reactor, 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 h;

[0064] S3. After the second step of the 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. 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 polyetherester-based elastomer prepared in S3 are melt-spun in parallel at a composite ratio of 4:1, wherein the viscosity of the PA6-based polyetherester-based elastomer is 2.25, and the viscosity of PA6 is 2.6. The obtained reinforced PA6-based parallel composite elastic fiber has a linear density of 50.8 dtex, a strength of 3.48 cN / dtex, an elongation at break of 46%, and an elastic recovery rate of 92% after ten cycles of a 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 100 g of caprolactam, 5 g of deionized water, 5.8 g of PTA, 2 g of 6-aminocaproic acid, and 0.2 g of Irganox1010 to a reaction vessel. After nitrogen is introduced to replace the air in the reactor, the pressure is increased to 2.5 bar. At a stirring speed of 120 r / min, the temperature is raised to 240° C., and the reaction is carried out for 2 h. The pressure is then reduced to 5000 Pa and the reaction is continued for 1 h. The obtained double-end carboxyl PA6 prepolymer is left in the polymerization vessel for the next 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 h;

[0070] S3. After the second step of the 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 mixture is reacted 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. 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 polyetherester-based elastomer prepared in S3 are melt-spun in parallel at a composite ratio of 3:1, wherein the viscosity of the PA6-based polyetherester-based elastomer is 2.33, and the viscosity of PA6 is 2.75. The obtained reinforced PA6-based parallel composite elastic fiber has a linear density of 45.1 dtex, a strength of 3.51 cN / dtex, an elongation at break of 28%, and an elastic recovery rate of 98% at a fixed elongation of 5%.

[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 100 g of caprolactam, 5 g of deionized water, 5.8 g of PTA, 2 g of 8-aminooctanoic acid, and 0.2 g of triphenyl phosphate to a reaction vessel. After nitrogen is introduced to replace the air in the reactor, the pressure is increased to 2.5 bar. At a stirring speed of 120 r / min, the temperature is raised to 240° C., and the reaction is carried out for 2 h. The pressure is then reduced to 5000 Pa and the reaction is continued for 1 h. The obtained double-end carboxyl PA6 prepolymer is left in the polymerization vessel for the next 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 h;

[0076] S3. After the second step of the 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 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 2.5h 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 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 polyetherester-based elastomer prepared in S3 are melt-spun in parallel at a composite ratio of 4:1, wherein the viscosity of the PA6-based polyetherester-based elastomer is 2.4, and the viscosity of PA6 is 2.8. The obtained reinforced PA6-based parallel composite elastic fiber has a linear density of 49.1dtex, a strength of 3.32cN / dtex, an elongation at break of 35%, an elastic recovery rate of 93% after ten cycles with a fixed elongation of 15%, and an elastic recovery rate of 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 90 g of caprolactam, 4.5 g of deionized water, 5.3 g of PTA, 1.5 g of 6-aminoacetic acid, and 0.15 g of Irganox168 to a reaction vessel. After nitrogen is introduced to replace the air in the reactor, the pressure is increased to 2.5 bar. At a stirring speed of 120 r / min, the temperature is raised to 240° C., and the reaction is carried out for 2 h. The pressure is then reduced to 5000 Pa and the reaction is continued for 1 h. The obtained double-end carboxyl PA6 prepolymer remains in the polymerization vessel for the next 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 h;

[0082] S3. After the second step of the reaction is completed, the pressure is released to normal pressure, 49.5 g of regenerated polyether ester diol and 0.161 g 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 120 r / min for 1 hour. After that, the pressure is gradually reduced to 100 Pa, the temperature is raised to 260°C, and the polycondensation reaction is continued for 2 hours 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 39 MPa, the elongation at break is 628%, and the notched impact strength is 49 KJ / m 2 , Shore hardness is 49D, relative viscosity is 2.35;

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

[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 filament PA6 / TPAE parallel composite fiber is 2.14 cN / dtex, the strength of the PA6 / TPA6510 parallel composite yarn is 1.4 cN / dtex, and the strength of the PA6 / PBTE parallel fiber is 2.4 cN / dtex, indicating that the parallel elastic fiber of the present invention has significant advantages in strength; the commercial parallel yarn T400 has a breaking strength of 2.44 cN / dtex and an elongation at break of 21%. It can be seen that the elastic filament of the present invention is superior to T400 in both breaking strength and elongation.

[0087] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. 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. Stir caprolactam, deionized water, end-capping agent, ring-opening agent, and thermal stabilizer to obtain a double-end 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 prepared 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 the 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 polyetherester 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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