A micro-copolymer modified polyamide 66 fiber and its preparation method

Abstract

The present invention relates to a micro-copolymer modified polyamide 66 fiber and a preparation method thereof, in particular to a method for improving the dyeing performance of high-strength polyamide 66 fibers by copolymerizing a trace amount of nitrogen-containing six-membered heterocycles into the polyamide 66 main chain. The characteristics of the present invention are as follows: First, a nitrogen-containing six-membered heterocyclic compound is subjected to a salt-forming reaction with an aliphatic dicarboxylic acid or diamine to obtain an amide salt of the nitrogen-containing six-membered heterocycle. The amide salt is mixed with nylon 66 salt and subjected to melt polycondensation to obtain a nitrogen-containing six-membered heterocyclic copolymerized polyamide 66, and then micro-copolymer modified polyamide 66 fibers are obtained by melt spinning. The micro-copolymer modified polyamide 66 fibers prepared by the present invention have excellent mechanical properties and dyeing performance.

Description

Technical Field

[0001] The present invention belongs to the field of polyamide fiber preparation, and relates to a micro-copolymer modified polyamide 66 fiber and a preparation method thereof, in particular to a method for obtaining polyamide 66 fiber by melt spinning after preparing micro-copolymer modified polyamide 66 by introducing a nitrogen-containing six-membered heterocycle into the polyamide 66 molecular chain. Background Art

[0002] Polyamide 66 fiber has excellent strength, wear resistance and corrosion resistance, and is widely used in the fields of clothing, industrial use and home textiles. High-strength polyamide 66 fiber, with its excellent mechanical properties, shows great application potential in high-end application markets such as military training uniforms and outdoor sports clothing. However, the dyeing performance of high-strength polyamide 66 fiber is relatively poor, which limits its color diversity and aesthetic degree. Therefore, in-depth research on effective methods to improve the dyeing performance of high-strength polyamide 66 fiber is of great significance for expanding its application scope, enhancing product competitiveness and meeting the diversified market demands.

[0003] The problem of poor dyeing performance exists in the actual application of high-strength polyamide 66 fiber, mainly due to the following two aspects: on the one hand, currently, the dyeing of polyamide 66 fiber mainly uses acid dyes, which achieve dyeing by combining with the terminal amino groups in the fiber molecules. However, the preparation of high-strength polyamide 66 uses end-group condensation reaction to combine the terminal amino groups with the terminal carboxyl groups to generate higher molecular weight polyamide 66, which significantly reduces the number of dyeable groups (i.e., terminal amino groups) in the fiber. The terminal amino group, as the key "dyeing site" for dye molecule binding, the reduction in its number directly affects the dyeing performance of the fiber. On the other hand, the molecular crystallinity and orientation degree of high-strength polyamide 66 fiber are relatively high. The crystalline region hinders the adsorption and diffusion of dyes. At the same time, the high orientation degree means that the fiber molecular chains are arranged more orderly, further increasing the difficulty for dye molecules to penetrate into the fiber interior.

[0004] Chinese Patent CN117758525A discloses a dyeing method for high-strength polyamide 66 fabric, which completes the dyeing process through steps such as pretreatment, dyeing, soaping, color fixation and shaping. During the dyeing process, acid dyes with various molecular structures are used in combination, and combined with the three-stage temperature-rising dyeing technology, the dyeing of dyes is realized, so as to obtain better color fastness. However, this patent only optimizes the dyeing process to improve the dyeing performance of high-strength polyamide 66, and fails to fundamentally solve the technical bottleneck of difficult dyeing of high-strength polyamide 66 fiber, such as the insufficient number of "dyeing sites" and the limitations of high crystallinity and high orientation degree of the fiber. Summary of the Invention

[0005] The present invention provides a micro-copolymer modified polyamide 66 fiber and a preparation method thereof, in particular to a method for preparing a polyamide 66 fiber by introducing a nitrogen-containing six-membered heterocycle into the polyamide 66 molecular chain and then obtaining the polyamide 66 fiber through melt spinning.

[0006] The polyamide 66 fiber prepared by the present invention has a nitrogen-containing six-membered heterocycle introduced into the main chain of its molecule. The basic nitrogen atoms contained therein increase the number of "dyeing sites" in the molecular chain during dyeing, thereby improving the dye uptake rate of the polyamide 66 fiber. Different from the terminal amino group of polyamide 66, the "dyeing sites" of the nitrogen-containing six-membered heterocycle will not decrease with the increase in the molecular weight of polyamide 66, showing obvious advantages in improving the dyeing performance of high-strength polyamide 66 fibers, and being applicable to the viscosity increase of polyamide 66 with different molecular weights and meeting the requirements for improving the dyeing performance of polyamide 66 fibers with different strengths. In addition, the nitrogen-containing six-membered heterocycle is a rigid group, and the introduction of a small amount of nitrogen-containing six-membered heterocycle can moderately reduce the regularity of the polyamide 66 molecular chain, which is more conducive to the diffusion and combination of dyes inside the fiber.

[0007] The present invention provides a micro-copolymer modified polyamide 66 fiber having the following structure:

[0008]

[0009] In the formula, n is 4 to 10, x is 39 to 105, y is 1 to 43, and the structural formula of R is as follows:

[0010]

[0011] The present invention also provides a preparation method for the above-mentioned micro-copolymer modified polyamide 66 fiber, and the specific steps are as follows:

[0012] (1) A nitrogen-containing six-membered heterocyclic compound and an aliphatic dicarboxylic acid or diamine are added to water or ethanol in a certain proportion, and a salt-forming reaction is carried out by stirring at 60 to 90 °C for 1 to 12 h. After the salt precipitates, it is filtered, washed, and dried to obtain an amide salt of the nitrogen-containing six-membered heterocycle;

[0013] (2) 1 to 100 parts of the amide salt of the nitrogen-containing six-membered heterocycle, 75 to 105 parts of nylon 66 salt, and 60 to 80 parts of deionized water are added to a polymerization reaction kettle, and the air in the kettle is replaced with nitrogen 3 times; heating is started, and the temperature is slowly raised to 215 to 235 °C, and the pressure is maintained at 1.8 to 2.0 MPa for polycondensation for 2 to 3 h; the temperature is further raised to 245 to 255 °C, and the pressure is reduced to atmospheric pressure of 0 MPa within 0.5 to 1 h; the temperature is further raised to 270 to 280 °C, and the vacuum is pumped to a pressure of -0.01 to -0.10 MPa, and heat preservation and pressure maintenance are carried out for 1 to 3 h to obtain a nitrogen-containing six-membered heterocycle copolymerized polyamide 66;

[0014] (3) Mix the nitrogen-containing six-membered heterocyclic copolymerized polyamide 66 or the nitrogen-containing six-membered heterocyclic copolymerized polyamide 66 and the conventional polyamide 66 in a certain proportion and carry out spinning in a melt spinning machine to obtain the micro-copolymer modified polyamide 66 fiber.

[0015] In the preparation method of a micro-copolymer modified polyamide 66 fiber as described above, in step (1), the nitrogen-containing six-membered heterocyclic compound includes a nitrogen-containing six-membered heterocyclic dibasic acid and a nitrogen-containing six-membered heterocyclic diamine. The nitrogen-containing six-membered heterocyclic dibasic acid includes one or more of 2,6-pyridinedicarboxylic acid, 2,5-pyridinedicarboxylic acid, 2,4-pyridinedicarboxylic acid, 2,3-pyridinedicarboxylic acid, 3,5-pyridinedicarboxylic acid, 3,4-pyridinedicarboxylic acid, 2,5-pyrimidinedicarboxylic acid, 2,3-pyrazinedicarboxylic acid, 2,6-pyrazinedicarboxylic acid, 2,5-pyrazinedicarboxylic acid, 4,5-pyridazinedicarboxylic acid, 3,6-pyridazinedicarboxylic acid; the pyridine ring-containing diamine includes one or more of 2,6-diaminopyridine, 2,5-diaminopyridine, 2,4-diaminopyridine, 2,3-diaminopyridine, 3,5-diaminopyridine, 3,4-diaminopyridine, 4,6-diaminopyrimidine, 2,4-diaminopyrimidine, 4,5-diaminopyrimidine, 2,6-diaminopyrazine, 4,5-diaminopyridazine, 3,6-diaminopyridazine; the aliphatic dibasic acid is a straight-chain aliphatic dibasic acid with 4 to 12 carbon atoms; the aliphatic diamine is a straight-chain aliphatic diamine with 4 to 10 carbon atoms.

[0016] In the preparation method of a micro-copolymer modified polyamide 66 fiber as described above, in step (1), when the nitrogen-containing six-membered heterocyclic compound is in the diamine structure, the nitrogen-containing six-membered heterocyclic diamine and the aliphatic dibasic acid carry out a salt-forming reaction in a molar ratio of 1.02 to 1.05:1; when the nitrogen-containing six-membered heterocyclic compound is in the dibasic acid structure, the nitrogen-containing six-membered heterocyclic dibasic acid and the aliphatic diamine carry out a salt-forming reaction in a molar ratio of 1:1.02 to 1.05.

[0017] In the preparation method of a micro-copolymer modified polyamide 66 fiber as described above, in step (2), the number-average molecular weight of the nitrogen-containing six-membered heterocyclic copolymerized polyamide 66 is 17000 to 24000 g / mol.

[0018] In the preparation method of a micro-copolymer modified polyamide 66 fiber as described above, in step (3), when x is 66 to 105 and y is 1 to 7, the nitrogen-containing six-membered heterocyclic copolymerized polyamide 66 can be directly spun; when x is 39 to 66 and y is 7 to 43, the nitrogen-containing six-membered heterocyclic copolymerized polyamide 66 and the conventional polyamide 66 can be mixed in a ratio of 1:18 to 98 and then spun.

[0019] A preparation method of the micro-copolymer modified polyamide 66 fiber as described above. In step (3), the conditions for melt spinning are as follows: the temperature is 280-290 °C, the winding speed is 2500-3500 m / min, and the draw ratio is 5-5.5.

[0020] The micro-copolymer modified polyamide 66 fiber as described above has a breaking strength of 6.5-8.2 cN / dtex, an elongation at break of 17.4-26.8%, the fabric obtained by weaving has a color fastness to washing of 4-5 grades, a dye uptake rate of 98.3-99.9%, and a K / S value of 22.0-26.5.

[0021] After the fiber is woven into a slender stocking tube by a hosiery machine, the dye uptake rate is measured with acid red N-2RBL or NAVY MPA acid dye according to "GB / T 23976.1-2009 Dyes - Determination of dye-uptake rate curve - Method for determination of dye uptake rate", the color fastness to washing is tested according to "GB / T 3921-2008 Textiles - Tests for color fastness - Color fastness to soaping", and the fastness grade is judged according to "GB / T 251-2008 Textiles - Tests for color fastness - Grey scale for assessing staining".

[0022] Adopting the technical solution of the present invention can achieve the following beneficial effects:

[0023] (1) Significantly improve the dyeing performance of high-strength polyamide 66 fiber: By introducing a nitrogen-containing six-membered heterocyclic structure into the main chain of the polyamide 66 fiber molecule, the number of "dyeing seats" in the molecular chain during dyeing is increased. This innovative design significantly improves the dye uptake rate of high-strength polyamide 66 fiber, overcoming the problem of poor dyeing performance of traditional polyamide 66 fiber due to insufficient number of "dyeing seats".

[0024] (2) Broaden the application range of polyamide 66 fiber: Due to the improvement of dyeing performance, high-strength polyamide 66 fiber can present richer colors and higher aesthetics, thus meeting the demand for color diversity in more fields. This helps to broaden the application range of polyamide 66 fiber, especially in the fields of textiles, clothing, home decoration, etc. that require high color expressiveness.

[0025] (3) Adapt to the requirements of viscosity increase of polyamide 66 with different molecular weights and different strength polyamide 66 fibers: The "dyeing seats" of the nitrogen-containing six-membered heterocyclic structure will not decrease with the increase of molecular weight during the viscosity increase of polyamide. This characteristic makes the present invention applicable to the dyeing of polyamide 66 fibers with different strength requirements, providing greater flexibility and adaptability. Specific embodiments

[0026] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0027] Example 1

[0028] A preparation method of a micro-copolymer modified polyamide 66 fiber is as follows:

[0029] (1) 2,6-pyridinedicarboxylic acid and 1,6-hexanediamine are added to water in a molar ratio of 1:1.02, and a salt-forming reaction is carried out by stirring at 90 °C for 1 h. After the salt precipitates, it is filtered, washed, and dried to obtain an amide salt containing a nitrogenous six-membered heterocycle;

[0030] (2) 1 part of the amide salt containing a nitrogenous six-membered heterocycle, 75 parts of nylon 66 salt, and 60 parts of deionized water are added to a polymerization reaction kettle, and the air in the kettle is replaced with nitrogen 3 times; heating is started, and the temperature is slowly raised to 215 °C, and polycondensation is carried out at a pressure of 1.8 MPa for 2 h; the temperature is continued to be raised to 245 °C, and the pressure is reduced to atmospheric pressure of 0 MPa in 0.5 h; the temperature is continued to be raised to 275 °C, and the vacuum is pumped to a pressure of -0.01 MPa, and heat preservation and pressure maintenance are carried out for 1 h to obtain a nitrogenous six-membered heterocycle copolymerized polyamide 66, the number average molecular weight of which is 17100 g / mol, and the molecular structural formula is:

[0031]

[0032] (3) The nitrogenous six-membered heterocycle copolymerized polyamide 66 is spun in a melt spinning machine, the spinning temperature is 280 °C, the winding speed is 2500 m / min, and the drawing ratio is 5.0 to obtain a micro-copolymer modified polyamide 66 fiber.

[0033] After the fiber is woven into a slender sock tube by a sock knitting machine, the dye uptake rate is measured with acid red N-2RBL acid dye according to "GB / T 23976.1-2009 Dyes - Determination of dye uptake rate curve - Method for determination of dye uptake rate", the color fastness to soaping is tested according to "GB / T 3921-2008 Textiles - Tests for color fastness - Color fastness to soaping", and the fastness grade is judged according to "GB / T 251-2008 Textiles - Tests for color fastness - Grey scale for assessing staining".

[0034] Example 2

[0035] A preparation method of a micro-copolymer modified polyamide 66 fiber is as follows:

[0036] (1) 2,4-Pyridinedicarboxylic acid and 1,6-hexanediamine were added to water in a molar ratio of 1:1.03, and a salt-forming reaction was carried out by stirring at 80 °C for 12 h. After the salt precipitated, it was filtered, washed, and dried to obtain an amide salt of a six-membered nitrogen heterocycle;

[0037] (2) 2 parts of the amide salt of a six-membered nitrogen heterocycle, 100 parts of nylon 66 salt, and 70 parts of deionized water were added to a polymerization reactor, and the air in the reactor was replaced with nitrogen 3 times; heating was started, and the temperature was slowly raised to 225 °C, and polycondensation was carried out at a pressure of 1.9 MPa for 3 h; the temperature was further raised to 250 °C, and the pressure was reduced to atmospheric pressure 0 MPa in 0.7 h; the temperature was further raised to 270 °C, and the vacuum was pumped to a pressure of -0.05 MPa, and the temperature and pressure were maintained for 2 h to obtain a six-membered nitrogen heterocycle copolymerized polyamide 66, whose number-average molecular weight was 23000 g / mol, and the molecular structural formula was:

[0038]

[0039] (3) The six-membered nitrogen heterocycle copolymerized polyamide 66 was spun in a melt spinning machine, the spinning temperature was 282 °C, the winding speed was 3500 m / min, and the draw ratio was 4.5 to obtain a micro-copolymer modified polyamide 66 fiber.

[0040] After the fiber was knitted into a slender stocking tube by a hosiery machine, the dye uptake rate was measured with Acid Red N-2RBL acid dye according to "GB / T 23976.1-2009 Dyes - Determination of dye-uptake rate curves - Method for determination of dye-uptake rate", the color fastness to soaping was tested according to "GB / T 3921-2008 Textiles - Tests for color fastness - Color fastness to soaping", and the fastness grade was judged according to "GB / T 251-2008 Textiles - Tests for color fastness - Grey scale for assessing staining".

[0041] Example 3

[0042] A preparation method of a micro-copolymer modified polyamide 66 fiber, the specific steps are as follows:

[0043] (1) 2,5-Pyridinedicarboxylic acid and 1,6-hexanediamine were added to water in a molar ratio of 1:1.04, and a salt-forming reaction was carried out by stirring at 70 °C for 4 h. After the salt precipitated, it was filtered, washed, and dried to obtain an amide salt of a six-membered nitrogen heterocycle;

[0044] (2) Add 3 parts of amide salt of nitrogen-containing six-membered heterocycle, 105 parts of nylon 66 salt, and 80 parts of deionized water into the polymerization reactor, and displace the air in the reactor with nitrogen for 3 times; turn on the heating, slowly raise the temperature to 235 °C, and keep the pressure at 2.0 MPa for polycondensation for 2.5 h; continue to raise the temperature to 255 °C, and reduce the pressure to atmospheric pressure 0 MPa in 0.8 h; continue to raise the temperature to 278 °C, evacuate to a pressure of -0.08 MPa, and keep the temperature and pressure for 2 h to obtain nitrogen-containing six-membered heterocycle copolymerized polyamide 66, whose number-average molecular weight is 24300 g / mol, and the molecular structural formula is:

[0045]

[0046] (3) The nitrogen-containing six-membered heterocycle copolymerized polyamide 66 is spun in a melt spinning machine, the spinning temperature is 285 °C, the winding speed is 3000 m / min, and the draw ratio is 5.2 to obtain micro-copolymer modified polyamide 66 fiber.

[0047] After the fiber is knitted into a slender stocking tube by a hosiery machine, the dye uptake rate is measured with NAVY MPA acid dye according to "GB / T 23976.1-2009 Dyes - Determination of dye-uptake rate curves - Method for determination of dye-uptake rate", the color fastness to soaping is tested according to "GB / T 3921-2008 Textiles - Tests for color fastness - Color fastness to soaping", and the fastness grade is judged according to "GB / T 251-2008 Textiles - Tests for color fastness - Grey scale for assessing staining".

[0048] Example 4

[0049] A preparation method of micro-copolymer modified polyamide 66 fiber, the specific steps are as follows:

[0050] (1) Add 2,6-diaminopyridine and adipic acid into water at a molar ratio of 1:1.05, stir at 60 °C for 6 h for salt formation reaction, after the salt precipitates, filter, wash, and dry to obtain the amide salt of nitrogen-containing six-membered heterocycle;

[0051] (2) Add 74 parts of amide salt of nitrogen-containing six-membered heterocycle, 80 parts of nylon 66 salt, and 80 parts of deionized water into the polymerization reactor, and displace the air in the reactor with nitrogen for 3 times; turn on the heating, slowly raise the temperature to 225 °C, and keep the pressure at 1.9 MPa for polycondensation for 3 h; continue to raise the temperature to 250 °C, and reduce the pressure to atmospheric pressure 0 MPa in 1 h; continue to raise the temperature to 280 °C, evacuate to a pressure of -0.02 MPa, and keep the temperature and pressure for 2 h to obtain nitrogen-containing six-membered heterocycle copolymerized polyamide 66, whose number-average molecular weight is 17800 g / mol, and the molecular structural formula is:

[0052]

[0053] (3)The nitrogen-containing six-membered heterocyclic copolyamide 66 and conventional polyamide 66 are mixed in a ratio of 1:48 and then spun in a melt spinning machine. The spinning temperature is 286 °C, the winding speed is 3100 m / min, and the draw ratio is 5.3 to obtain micro-copolymer modified polyamide 66 fiber.

[0054] After the fiber is knitted into a slender stocking tube by a hosiery machine, the dye uptake rate is measured with NAVY MPA acid dye according to "GB / T 23976.1-2009 Dyes - Determination of dye-uptake rate curve - Method for determination of dye-uptake rate". The color fastness to soaping is tested according to "GB / T 3921-2008 Textiles - Tests for color fastness - Color fastness to soaping". The fastness grade is judged according to "GB / T 251-2008 Textiles - Tests for color fastness - Grey scale for assessing staining".

[0055] Example 5

[0056] A preparation method of micro-copolymer modified polyamide 66 fiber, the specific steps are as follows:

[0057] (1)2,6-Diaminopyridine and adipic acid are added to water in a molar ratio of 1:1.03, and salt formation reaction is carried out by stirring at 90 °C for 5 h. After the salt precipitates, it is filtered, washed, and dried to obtain the amide salt of nitrogen-containing six-membered heterocycle.

[0058] (2)76 parts of the amide salt of nitrogen-containing six-membered heterocycle, 78 parts of nylon 66 salt, and 80 parts of deionized water are added to a polymerization reactor, and the air in the reactor is replaced with nitrogen 3 times; heating is started, and the temperature is slowly raised to 235 °C, and polycondensation is carried out at a pressure of 2.0 MPa for 2.5 h; the temperature is continued to be raised to 250 °C, and the pressure is reduced to atmospheric pressure of 0 MPa in 0.5 h; the temperature is continued to be raised to 275 °C, and the vacuum is pumped to a pressure of -0.04 MPa, and heat and pressure are maintained for 2 h to obtain nitrogen-containing six-membered heterocyclic copolyamide 66, whose number average molecular weight is 17100 g / mol, and the molecular structural formula is:

[0059]

[0060] (3)The nitrogen-containing six-membered heterocyclic copolyamide 66 and conventional polyamide 66 are mixed in a ratio of 1:18 and then spun in a melt spinning machine. The spinning temperature is 288 °C, the winding speed is 3000 m / min, and the draw ratio is 5.3 to obtain micro-copolymer modified polyamide 66 fiber.

[0061] After the fibers are woven into slender sock tubes by a hosiery machine, the dye uptake rate is measured using Acid Red N-2RBL acid dye according to "GB / T 23976.1-2009 Dyes - Determination of the dyeing rate curve - Method for determination of the percentage of dye uptake", the color fastness to soaping is tested according to "GB / T 3921-2008 Textiles - Tests for color fastness - Color fastness to soaping", and the fastness grade is judged according to "GB / T 251-2008 Textiles - Tests for color fastness - Grey scale for assessing staining".

[0062] Example 6

[0063] A preparation method of a micro-copolymer modified polyamide 66 fiber, the specific steps are as follows:

[0064] (1) 2,6-Diaminopyridine and adipic acid are added to water in a molar ratio of 1:1.03, and a salt-forming reaction is carried out by stirring at 80 °C for 6 h. After the salt precipitates, it is filtered, washed, and dried to obtain an amide salt containing a six-membered nitrogen heterocycle;

[0065] (2) 86 parts of the amide salt containing a six-membered nitrogen heterocycle, 80 parts of nylon 66 salt, and 70 parts of deionized water are added to a polymerization reactor, and the air in the reactor is replaced with nitrogen 3 times; heating is started, and the temperature is slowly raised to 230 °C, and the pressure is maintained at 1.8 MPa for polycondensation for 3 h; the temperature is further raised to 255 °C, and the pressure is reduced to atmospheric pressure of 0 MPa in 1 h; the temperature is further raised to 273 °C, and the vacuum is pumped to a pressure of -0.05 MPa, and heat and pressure are maintained for 3 h to obtain a six-membered nitrogen heterocycle copolymerized polyamide 66, the number average molecular weight of which is 18400 g / mol, and the molecular structural formula is:

[0066]

[0067] (3) The six-membered nitrogen heterocycle copolymerized polyamide 66 and conventional polyamide 66 are mixed in a ratio of 1:98 and then spun in a melt spinning machine. The spinning temperature is 290 °C, the winding speed is 3000 m / min, and the draw ratio is 5.5 to obtain a micro-copolymer modified polyamide 66 fiber.

[0068] After the fibers are woven into slender sock tubes by a hosiery machine, the dye uptake rate is measured using NAVY MPA acid dye according to "GB / T 23976.1-2009 Dyes - Determination of the dyeing rate curve - Method for determination of the percentage of dye uptake", the color fastness to soaping is tested according to "GB / T 3921-2008 Textiles - Tests for color fastness - Color fastness to soaping", and the fastness grade is judged according to "GB / T 251-2008 Textiles - Tests for color fastness - Grey scale for assessing staining".

[0069] Comparative Example 1

[0070] Polyamide 66 with a number-average molecular weight of 17,000 g / mol was spun in a melt spinning machine at a spinning temperature of 285 °C, a winding speed of 2,500 m / min, and a draw ratio of 5.0 to obtain polyamide 66 fibers.

[0071] After the fibers were woven into slender sock tubes by a hosiery machine, the dye uptake rate was measured using Acid Red N-2RBL acid dye according to "GB / T 23976.1-2009 Dyes - Determination of dye-uptake rate curves - Method for determination of percentage dye-uptake". The color fastness to soaping was tested according to "GB / T 3921-2008 Textiles - Tests for color fastness - Color fastness to soaping". The fastness grade was judged according to "GB / T 251-2008 Textiles - Tests for color fastness - Grey scale for assessing staining".

[0072] Comparative Example 2

[0073] Polyamide 66 with a number-average molecular weight of 24,000 g / mol was spun in a melt spinning machine at a spinning temperature of 295 °C, a winding speed of 3,000 m / min, and a draw ratio of 5.5 to obtain polyamide 66 fibers.

[0074] After the fibers were woven into slender sock tubes by a hosiery machine, the dye uptake rate was measured using NAVY MPA acid dye according to "GB / T 23976.1-2009 Dyes - Determination of dye-uptake rate curves - Method for determination of percentage dye-uptake". The color fastness to soaping was tested according to "GB / T 3921-2008 Textiles - Tests for color fastness - Color fastness to soaping". The fastness grade was judged according to "GB / T 251-2008 Textiles - Tests for color fastness - Grey scale for assessing staining".

[0075] The data tables of the mechanical properties and dyeing properties of the micro-copolymer modified polyamide 66 fibers in each example and comparative example are shown in Table 1 below:

[0076] Table 1 Data tables of the mechanical properties and dyeing properties of the micro-copolymer modified polyamide 66 fibers

[0077]

[0078] The above examples only represent several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A micro-copolymer modified polyamide 66 fiber, characterized in that: The raw material is nitrogen-containing six-membered heterocyclic copolymer polyamide 66, and its structural formula is as follows: or ； Wherein, n is 4~10, x is 39~105, y is 1~43, and the structural formula of R is as follows: 。 2. A method for preparing a micro-copolymerized modified polyamide 66 fiber, comprising preparing the micro-copolymerized modified polyamide 66 fiber as claimed in claim 1, characterized in that: The following steps are involved: (1) A nitrogen-containing six-membered heterocyclic compound and an aliphatic dibasic acid or diamine are added to water or ethanol in a certain proportion, and stirred at 60-90°C for 1-12 hours to perform a salt-forming reaction. After the salt is precipitated, it is filtered, washed, and dried to obtain an amide salt of a nitrogen-containing six-membered heterocyclic compound; (2) Add 1-100 parts of nitrogen-containing six-membered heterocyclic amide salt, 75-105 parts of nylon 66 salt, and 60-80 parts of deionized water into a polymerization reactor, and replace the air in the reactor with nitrogen three times; turn on the heating, slowly raise the temperature to 215-235°C, and maintain the pressure at 1.8-2.0 MPa for condensation for 2-3 hours; continue to raise the temperature to 245-255°C, and reduce the pressure to normal pressure after 0.5-1 hour; continue to raise the temperature to 270-280°C, evacuate to a pressure of -0.01-0.10 MPa, and maintain the temperature and pressure for 1-3 hours to obtain nitrogen-containing six-membered heterocyclic copolymer polyamide 66; (3) The nitrogen-containing six-membered heterocyclic copolymer polyamide 66 or the nitrogen-containing six-membered heterocyclic copolymer polyamide 66 and conventional polyamide 66 are mixed in a certain proportion and then spun in a melt spinning machine to obtain micro-copolymer modified polyamide 66 fibers.

3. The method for preparing a micro-copolymerized modified polyamide 66 fiber according to claim 2, characterized in that: In step (1), the nitrogen-containing six-membered heterocyclic compound includes a nitrogen-containing six-membered heterocyclic dibasic acid and a nitrogen-containing six-membered heterocyclic diamine. The nitrogen-containing six-membered heterocyclic dibasic acid includes one or more of 2,6-pyridinedicarboxylic acid, 2,5-pyridinedicarboxylic acid, 2,4-pyridinedicarboxylic acid, 2,3-pyridinedicarboxylic acid, 3,5-pyridinedicarboxylic acid, and 3,4-pyridinedicarboxylic acid. The nitrogen-containing six-membered heterocyclic diamine includes one or more of 2,6-diaminopyridine, 2,5-diaminopyridine, 2,4-diaminopyridine, 2,3-diaminopyridine, 3,5-diaminopyridine, and 3,4-diaminopyridine. The aliphatic dibasic acid is a straight-chain aliphatic dibasic acid having 4 to 12 carbon atoms. The aliphatic diamine is a straight-chain aliphatic diamine having 4 to 10 carbon atoms.

4. The method for preparing a micro-copolymerized modified polyamide 66 fiber according to claim 2, characterized in that: In step (1), when the nitrogen-containing six-membered heterocyclic compound is a diamine structure, the nitrogen-containing six-membered heterocyclic diamine and the aliphatic dibasic acid are subjected to a salt-forming reaction at a molar ratio of 1.02 to 1.05:1; when the nitrogen-containing six-membered heterocyclic compound is a dibasic acid structure, the nitrogen-containing six-membered heterocyclic dibasic acid and the aliphatic diamine are subjected to a salt-forming reaction at a molar ratio of 1:1.02 to 1.

05.

5. The method for preparing a micro-copolymerized modified polyamide 66 fiber according to claim 2, characterized in that: In step (2), the number average molecular weight of the nitrogen-containing six-membered heterocyclic copolymer polyamide 66 is 17000-24000 g / mol.

6. The method for preparing a micro-copolymerized modified polyamide 66 fiber according to claim 2, characterized in that: In step (3), when x is 66-105 and y is 1-7, the nitrogen-containing six-membered heterocyclic copolymer polyamide 66 is directly spun; when x is 39-66 and y is 7-43, the nitrogen-containing six-membered heterocyclic copolymer polyamide 66 and conventional polyamide 66 are mixed in a ratio of 1:18-98 and then spun.

7. The method for preparing a micro-copolymerized modified polyamide 66 fiber according to claim 2, characterized in that: The melt spinning conditions in step (3) are a temperature of 280-290° C., a winding speed of 2500-3500 m / min, and a stretching ratio of 5-5.

5.

8. The method for preparing a micro-copolymerized modified polyamide 66 fiber according to claim 2, characterized in that: The micro-copolymer modified polyamide 66 fiber has a breaking strength of 6.5-8.2 cN / dtex, an elongation at break of 17.4-26.8%, and the woven fabric has a color fastness to washing of level 4-5, a color uptake of 98.3-99.9%, and a K / S value of 22.0-26.5.

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