Polyamide resin, method for preparing the same, and use thereof

Abstract

The application provides a kind of polyamide resin and its preparation method and application, the polyamide resin is prepared with hexanediamine and adipic acid as starting material polyhexamethylene adipate;With polyamide resin as benchmark, the polyamide resin also includes 3wt% or more first functional monomer and 0.5-3wt% second functional monomer;The polyamide resin obtained by the application is good when used for preparing polyamide fiber, and the fiber strength is higher, suitable for producing single fiber fineness below 0.5dpf, when the spinning speed is 4000m / min or more, the production condition is stable, and the product performance is excellent;The polyamide resin obtained by the application is suitable for preparing polyamide fiber.

Description

Technical Field

[0001] This invention belongs to the field of spinning technology, and relates to a spinning material, particularly a polyamide resin and its preparation method and application. Background Technology

[0002] Polyamide (PA) is a polymer formed by the polymerization of monomers containing carboxyl and amino groups through amide bonds. Due to its simple manufacturing process and excellent durability and strength, it is widely used in textiles, automotive parts, electronics, food packaging and other fields. Among them, polyamide 66 is a product of the condensation polymerization of adipic acid and hexamethylenediamine. Because it is easy to make into fine filaments and the textiles made from it are of excellent quality, it has become a mainstream raw material in the textile industry.

[0003] CN 109503829A discloses a spinning-grade polyamide 66 resin for bright profiled yarns and its preparation method. The spinning-grade polyamide 66 resin for bright profiled yarns is a polyhexamethylene adipamide prepared from hexamethylenediamine and adipic acid as starting materials. It contains 1-5‰ of a molecular weight regulator, 0.3-1‰ of a photothermal stabilizer, 1-5% of caprolactam, and 0.3-1.5% of a comonomer. The comonomer is a diamine or a diacid. The diamine is selected from any one of 2-ethylpentanediamine, 2-methylpentanediamine, or 2-methylhexamethylenediamine. The diacid is selected from any one of 2-methylglutaric acid, 2-glutaric acid, or 2-methylhexamethylenediamine.

[0004] CN 106633828A discloses a halogen-free flame-retardant polyamide 66 and its preparation method. First, a flame retardant salt is obtained by reacting a DPO-based reactive phosphorus flame retardant with a diamine. Then, during the polymerization of the 66 salt into polyamide 66, additive phosphorus flame retardants and flame retardant salts are added to obtain halogen-free flame-retardant polyamide 66. The molecular chain of halogen-free flame-retardant polyamide 66 is composed of polyamide segments and DPO-based reactive phosphorus flame retardant segments. The phosphorus content in the molecular chain is 0.4-0.8 wt%, and the molecular chains contain 4-9 wt% additive phosphorus flame retardant.

[0005] CN 109023566A discloses a method for preparing high-strength, high-shrinkage polyamide 66 filaments, comprising the following steps: (1) preparing a spinning solution; (2) spinning and forming; (3) drying and oiling; and (4) drawing and setting. The spinning solution is prepared by using a polyamide 66 copolymer comprising 60-75% by 25-40% by weight of a polyamide 66 component and an antistatic component as raw material, and formic acid as a solution, stirring with a magnetic stirrer at room temperature until completely dissolved to obtain the spinning solution. The mass percentage concentration of the polyamide 66 copolymer is 14-16%.

[0006] The aforementioned existing technologies have prepared polyamides that meet different process requirements to address different process needs. Ultrafine polyamide fibers refer to fibers with a single fiber fineness of less than 0.5 dpf. Due to the low single fiber fineness, their spinning speed is as high as 4000 m / min, and they are prone to fiber drift and breakage during production. Therefore, they have high requirements for the spinnability of polyamide resin and fiber strength.

[0007] Therefore, there is a need to provide a polyamide resin that meets fiber strength requirements and has good spinnability, as well as its preparation method and application, and in particular, a polyamide resin for ultrafine polyamide fibers, its preparation method and application. Summary of the Invention

[0008] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a polyamide resin, its preparation method and application. The polyamide resin is suitable for producing fibers with a single fiber fineness of less than 0.5 dpf. When the spinning speed is above 4000 m / min, there is no fiber drift or breakage. It has good spinnability and high fiber strength.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a polyamide resin, wherein the polyamide resin is prepared from hexamethylenediamine and adipic acid as starting materials to obtain polyhexamethylene adipamide;

[0011] Based on polyamide resin, the polyamide resin further includes more than 2 wt% of a first functional monomer and 0.5-3 wt% of a second functional monomer;

[0012] The first functional monomer includes any one or a combination of at least two of the following: C4-C6 lactams, C4-C10 branched diamines, or C4-C10 branched dicarboxylic acids.

[0013] The second functional monomer is a functional monomer containing a heterocyclic structure and / or an aromatic ring structure.

[0014] The polyamide resin of the present invention comprises more than 2 wt% of a first functional monomer, for example, it may be 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 8 wt%, 10 wt%, 12 wt%, or 15 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable. Preferably, it is more than 3 wt% and less than 10 wt%.

[0015] The polyamide resin of the present invention includes 0.5-3 wt% of a second functional monomer, for example, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, or 3 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0016] The polyamide resin described in this invention, through the synergistic addition of a first functional monomer and a second functional monomer, achieves the ability to produce fibers with a single fiber fineness of less than 0.5 dpf. At a spinning speed of 4000 m / min or higher, the production conditions are stable, the product indicators are excellent, and it has good spinnability and high fiber strength.

[0017] Preferably, the C4-C6 lactams include valproic acid lactam and / or caprolactam.

[0018] Preferably, the C4-C10 branched diamine includes any one or a combination of at least two of methylpentanediamine, ethylpentanediamine, isopropylpentanediamine, dimethylpentanediamine, methylhexanediamine, ethylhexanediamine, isopropylhexanediamine, or dimethylhexanediamine. Typical but non-limiting combinations include combinations of methylpentanediamine and ethylpentanediamine, combinations of isopropylpentanediamine and dimethylpentanediamine, combinations of methylhexanediamine and ethylhexanediamine, combinations of isopropylhexanediamine and dimethylhexanediamine, combinations of methylpentanediamine, isopropylpentanediamine, and methylhexanediamine, combinations of methylpentanediamine, ethylpentanediamine, isopropylhexanediamine, and dimethylhexanediamine, or combinations of methylpentanediamine, ethylpentanediamine, isopropylpentanediamine, dimethylpentanediamine, methylhexanediamine, ethylhexanediamine, isopropylhexanediamine, and dimethylhexanediamine.

[0019] Preferably, the C4-C10 branched dicarboxylic acid includes any one or a combination of at least two of methylglutaric acid, ethylglutaric acid, isopropylglutaric acid, dimethylglutaric acid, methyl adipic acid, ethyl adipic acid, isopropyl adipic acid, or dimethyl adipic acid. Typical but non-limiting combinations include combinations of methylglutaric acid and ethylglutaric acid, combinations of isopropylglutaric acid and dimethylglutaric acid, combinations of dimethylglutaric acid and methyl adipic acid, combinations of ethyl adipic acid, isopropyl adipic acid, and dimethyl adipic acid, combinations of methylglutaric acid, ethylglutaric acid, isopropyl adipic acid, and dimethyl adipic acid, or combinations of methylglutaric acid, ethylglutaric acid, isopropyl adipic acid, dimethylglutaric acid, methyl adipic acid, ethyl adipic acid, isopropyl adipic acid, and dimethyl adipic acid.

[0020] Preferably, the second functional monomer comprises any one or a combination of at least two of furanyl dicarboxylic acid, 2-vinyl terephthalic acid, or diethyltoluene diamine. Typical but non-limiting combinations include a combination of furanyl dicarboxylic acid and 2-vinyl terephthalic acid, a combination of 2-vinyl terephthalic acid and diethyltoluene diamine, a combination of furanyl dicarboxylic acid and diethyltoluene diamine, or a combination of furanyl dicarboxylic acid, 2-vinyl terephthalic acid, and diethyltoluene diamine.

[0021] Preferably, based on the polyamide resin, the polyamide resin further includes 0.001-0.2 wt% of a molecular weight regulator, such as 0.001 wt%, 0.005 wt%, 0.01 wt%, 0.03 wt%, 0.05 wt%, 0.08 wt%, 0.1 wt%, 0.12 wt%, 0.15 wt%, 0.18 wt%, or 0.2 wt%, but not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 0.05-0.1 wt%.

[0022] Preferably, the molecular weight regulator is a branched monoamine with a carbon backbone of C4-C10, and more preferably 2-ethylhexylamine and / or 2-propyldecylamine.

[0023] In a second aspect, the present invention provides a method for preparing the polyamide resin as described in the first aspect, characterized in that the preparation method comprises the following steps:

[0024] (1) Mix nylon 66 salt solution, first functional monomer solution and second functional monomer solution according to the formula to obtain a premixed solution;

[0025] (2) Evaporate and concentrate the premixed solution obtained in step (1) to obtain a polyamide salt solution;

[0026] (3) Heating the polyamide salt solution obtained in step (2) to obtain a prepolymer, and continuing the reaction to obtain the polyamide resin.

[0027] The preparation method provided by this invention does not require the use of a catalyst, thus avoiding the adverse effects caused by catalyst addition. Moreover, the preparation method of this invention is simple, and the polyamide resin obtained has a relative viscosity of 2.4-2.6, exhibits good spinnability, and is suitable for industrial application.

[0028] The solvents for the nylon 66 salt solution, the first functional monomer solution, and the second functional monomer solution described in this invention are water, but this invention does not specifically limit the solvents.

[0029] Preferably, the nylon 66 salt solution in step (1) is a mixed solution of hexamethylenediamine and adipic acid.

[0030] Preferably, the nylon 66 salt solution in step (1) has a pH of 7-8 and a mass concentration of 45-55 wt%.

[0031] The pH value of the nylon 66 salt solution in step (1) of this invention is 7-8, for example, it can be 7, 7.2, 7.5, 7.8 or 8, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0032] The mass concentration of the nylon 66 salt solution in step (1) of this invention is 45-55 wt%, for example, it can be 45 wt%, 48 wt%, 50 wt%, 52 wt%, 54 wt% or 55 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0033] Preferably, in step (1), the first functional monomer solution is formed by salting the first functional monomer with adipic acid and / or hexamethylenediamine; the pH value of the first functional monomer solution is 7-8, and the mass concentration is 50-65 wt%.

[0034] In step (1) of the present invention, the pH value of the first functional monomer solution is 7-8, for example, it can be 7, 7.2, 7.5, 7.8 or 8, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0035] In step (1) of the present invention, the mass concentration of the first functional monomer solution is 50-65 wt%, for example, it can be 50 wt%, 52 wt%, 55 wt%, 58 wt%, 60 wt%, 62 wt% or 65 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0036] Preferably, in step (1), the second functional monomer solution is formed by salting the second functional monomer with adipic acid and / or hexamethylenediamine; the pH value of the second functional monomer solution is 7-8, and the mass concentration is 50-65 wt%.

[0037] Preferably, in step (1), the pH value of the second functional monomer solution is 7-8, and the mass concentration is 50-65 wt%.

[0038] In step (1) of this invention, the pH value of the second functional monomer solution is 7-8, for example, it can be 7, 7.2, 7.5, 7.8 or 8, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0039] In step (1) of the present invention, the mass concentration of the second functional monomer solution is 50-65 wt%, for example, it can be 50 wt%, 52 wt%, 55 wt%, 58 wt%, 60 wt%, 62 wt% or 65 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0040] The pH values ​​of the nylon 66 salt solution, the first functional monomer solution, and the second functional monomer solution described in this invention are adjusted by hexamethylenediamine or adipic acid, which will not be elaborated further here.

[0041] Preferably, the evaporation and concentration temperature in step (2) is 140-155℃, for example, it can be 140℃, 142℃, 145℃, 148℃, 150℃, 152℃ or 155℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0042] Preferably, the absolute pressure of evaporation and concentration in step (2) is 0.2-0.5 MPa, for example, it can be 0.2 MPa, 0.25 MPa, 0.3 MPa, 0.35 MPa, 0.4 MPa, 0.45 MPa or 0.5 MPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0043] Preferably, the mass concentration of the polyamide salt solution in step (2) is 70-80 wt%, for example, it can be 70 wt%, 72 wt%, 75 wt%, 76 wt%, 78 wt% or 80 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0044] Preferably, the temperature of the heating process in step (3) is 190-210℃, the absolute pressure is 1.5-2MPa, and the time is 50-60min.

[0045] The temperature for the heating process in step (3) is 190-210℃, for example, it can be 190℃, 195℃, 200℃, 205℃ or 210℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0046] The absolute pressure of the heating process in step (3) is 1.5-2 MPa, for example, it can be 1.5 MPa, 1.6 MPa, 1.7 MPa, 1.8 MPa, 1.9 MPa or 2 MPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0047] The heating time in step (3) is 50-60 min, for example, it can be 50 min, 52 min, 55 min, 58 min or 60 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0048] Preferably, the temperature for the continued reaction in step (3) is 270-280℃, the absolute pressure is 1.6-1.8MPa, and the time is 70-80min.

[0049] The temperature for the continued reaction in step (3) is 270-280℃, for example, it can be 270℃, 272℃, 275℃, 278℃ or 280℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0050] The absolute pressure for the continued reaction in step (3) is 1.5-2 MPa, for example, it can be 1.5 MPa, 1.6 MPa, 1.7 MPa, 1.8 MPa, 1.9 MPa or 2 MPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0051] The reaction time in step (3) is 70-80 min, for example, it can be 70 min, 72 min, 75 min, 78 min or 80 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0052] Preferably, the preparation method of the present invention further includes the step of adding a molecular weight regulator. The molecular weight regulator is mixed with the premixed solution during the concentration and evaporation process.

[0053] The preparation method of this invention further includes a post-treatment step after the reaction. This invention obtains the polyamide value through this post-treatment. The post-treatment consists of conventional pressure relief and post-polymerization. The endpoint of the pressure relief is an absolute pressure of 0-0.02 MPa; the absolute pressure of the post-polymerization is from -0.1 MPa to 0.1 MPa, and the time is 200-1000 s. Further details are omitted here.

[0054] As a preferred embodiment of the preparation method described in the second aspect of the present invention, the preparation method includes:

[0055] (1) A premixed solution is obtained by mixing a nylon 66 salt solution, a first functional monomer solution, and a second functional monomer solution according to the formula amount; the nylon 66 salt solution is a mixed solution of hexamethylenediamine and adipic acid, with a pH value of 7-8 and a mass concentration of 45-55 wt%; the first functional monomer solution is formed by salting the first functional monomer with adipic acid and / or hexamethylenediamine, with a pH value of 7-8 and a mass concentration of 50-65 wt%; the second functional monomer solution is formed by salting the second functional monomer with adipic acid and / or hexamethylenediamine, with a pH value of 7-8 and a mass concentration of 50-65 wt%.

[0056] (2) The premixed solution obtained in step (1) is evaporated and concentrated to obtain a polyamide salt solution with a mass concentration of 70-80 wt%; the temperature of the evaporation and concentration is 145-155℃ and the absolute pressure is 0.2-0.5 MPa;

[0057] (3) The polyamide salt solution obtained in step (2) is heated to obtain a prepolymer, and the reaction is continued to obtain the polyamide resin; the temperature of the heating treatment is 190-210℃, the absolute pressure is 1.5-2MPa, and the time is 50-60min; the temperature of the continued reaction is 270-280℃, the absolute pressure is 1.5-2MPa, and the time is 70-80min.

[0058] Thirdly, the present invention provides a polyamide fiber, which is prepared from the polyamide resin described in the first aspect;

[0059] The fineness of the matte polyamide fiber is ≤0.5dpf.

[0060] Fourthly, the present invention provides a semi-dull or matte polyamide fiber, wherein the semi-dull or matte polyamide fiber is prepared from the polyamide resin described in the first aspect;

[0061] Preferably, when preparing semi-dull or dull polyamide fibers, the titanium dioxide suspension is mixed with the premixed solution during the evaporation and concentration process.

[0062] As a further preferred technical solution, the titanium dioxide suspension is obtained by allowing the titanium dioxide grinding slurry to settle and become a supernatant liquid.

[0063] The raw materials for preparing the titanium dioxide suspension, by weight, include: 35-40 parts of titanium dioxide, 0.05-0.1 parts of phosphate dispersant, and 100 parts of solvent;

[0064] The titanium dioxide particle size D90 in the titanium dioxide grinding slurry is 0.5-1 μm.

[0065] In the preparation of the titanium dioxide grinding slurry of the present invention, the titanium dioxide is 35-40 parts by weight, for example, 35 parts, 36 parts, 37 parts, 38 parts, 39 parts or 40 parts, but not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 37-38 parts.

[0066] In the preparation of the titanium dioxide grinding slurry of the present invention, the phosphate dispersant is 0.05-0.1 parts by weight, for example, 0.05 parts, 0.06 parts, 0.07 parts, 0.08 parts, 0.09 parts or 0.1 parts, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 0.06-0.07 parts.

[0067] Preferably, the phosphate dispersant includes potassium phosphate dispersant and / or sodium phosphate dispersant, and more preferably potassium phosphate dispersant.

[0068] Preferably, the potassium phosphate dispersant comprises any one or a combination of at least two of potassium tripolyphosphate, tripotassium phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, or potassium pyrophosphate. Typical but non-limiting combinations include combinations of potassium tripolyphosphate and dipotassium hydrogen phosphate, combinations of dipotassium hydrogen phosphate and potassium dihydrogen phosphate, combinations of potassium dihydrogen phosphate and potassium pyrophosphate, combinations of potassium tripolyphosphate, dipotassium hydrogen phosphate, and potassium dihydrogen phosphate, or combinations of potassium tripolyphosphate, tripotassium phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, and potassium pyrophosphate.

[0069] Preferably, the solvent is water, and more preferably desalinated water.

[0070] More preferably, the method for preparing the titanium dioxide suspension includes the following steps:

[0071] (I) Mix titanium dioxide, phosphate dispersant and solvent according to the formula amount, and pre-disperse to obtain a pre-dispersed liquid;

[0072] (II) The pre-dispersed liquid obtained in grinding step (I) is used to obtain the grinding liquid;

[0073] (III) The grinding slurry obtained in step (II) is settled and precipitated, and the upper liquid is the titanium dioxide suspension.

[0074] The titanium dioxide particle size D90 in the titanium dioxide suspension is ≤1μm.

[0075] This invention does not further limit the pre-dispersion method described in step (I), as long as it can achieve the mixing of the formulated amounts of titanium dioxide, potassium phosphate dispersant, and solvent. For example, the pre-dispersion described in this invention is carried out in an emulsifier.

[0076] This invention, through pre-dispersion, enables sufficient wetting of titanium dioxide and achieves an initial reduction in titanium dioxide particle size, thereby reducing the pressure of subsequent grinding. Furthermore, when preparing the titanium dioxide suspension described in this invention, there is no need to add pH adjusters such as lactams, monoamines, or diamines, and the resulting titanium dioxide suspension exhibits excellent stability.

[0077] Preferably, the pre-dispersion temperature in step (I) is ≤20℃, for example, it can be 2℃, 4℃, 5℃, 6℃, 8℃, 10℃, 12℃, 15℃, 16℃, 18℃ or 20℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0078] The present invention controls the pre-dispersion temperature to ≤20℃, which is beneficial to reduce the agglomeration of titanium dioxide in the presence of potassium phosphate dispersants.

[0079] Preferably, the particle size D90 of titanium dioxide in the pre-dispersion liquid in step (I) is ≤2μm, for example, it can be 1.2μm, 1.3μm, 1.4μm, 1.5μm, 1.6μm, 1.7μm, 1.8μm, 1.9μm or 2μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 1.5-2μm.

[0080] Preferably, the particle size D90 of titanium dioxide in the grinding slurry in step (II) is ≤1μm, for example, it can be 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm or 1μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 0.5-1μm.

[0081] The grinding described in step (II) of this invention is carried out in a grinding machine. This invention does not further limit the grinding time, as long as the particle size D90 of titanium dioxide in the grinding fluid is ≤1μm.

[0082] Preferably, the temperature for settling in step (III) is 15-25°C, for example, 15°C, 16°C, 18°C, 20°C, 21°C, 24°C or 25°C, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0083] Preferably, the settling time in step (III) is 20-28 hours, for example, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, 25 hours, 26 hours, 27 hours or 28 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0084] Preferably, the titanium dioxide particle size D90 in the titanium dioxide suspension is ≤1μm, for example, it can be 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm or 1μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0085] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0086] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0087] When the polyamide resin obtained by this invention is used to prepare polyamide fibers, it has good spinnability and high fiber strength. It is suitable for producing fibers with a single fiber fineness of less than 0.5 dpf. When the spinning speed is above 4000 m / min, the production conditions are stable and the product indicators are excellent. The polyamide resin obtained by this invention is also suitable for preparing semi-dull or dull polyamide fibers. Detailed Implementation

[0088] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0089] Example 1

[0090] This embodiment provides a polyamide resin, wherein the polyamide resin is prepared from hexamethylenediamine and adipic acid as starting materials to obtain polyhexamethylene adipamide;

[0091] Based on polyamide resin, the polyamide resin comprises 5 wt% of a first functional monomer, 1.5 wt% of a second functional monomer, and 0.08 wt% of a molecular weight regulator;

[0092] The first functional monomer is caprolactam; the second functional monomer is 2-vinyl terephthalic acid; and the molecular weight regulator is 2-ethylhexylamine.

[0093] The preparation method of the polyamide resin includes the following steps:

[0094] (1) A premixed solution is obtained by mixing nylon 66 salt solution, first functional monomer solution and second functional monomer solution according to the formula amount; the nylon 66 salt solution is a mixed solution of hexamethylenediamine and adipic acid, with a pH value of 7.7 and a mass concentration of 53 wt%; the first functional monomer solution is formed by salting the first functional monomer and adipic acid, with a pH value of 7.2 and a mass concentration of 60 wt%; the second functional monomer solution is formed by salting the second functional monomer and hexamethylenediamine, with a pH value of 7.3 and a mass concentration of 60 wt%.

[0095] (2) The premixed solution obtained in step (1) is evaporated and concentrated to obtain a polyamide salt solution with a mass concentration of 75 wt%; the evaporation and concentration temperature is 150°C and the absolute pressure is 0.3 MPa; the molecular weight regulator is mixed with the premixed solution during the concentration and evaporation process;

[0096] (3) The polyamide salt solution obtained in step (2) is heated to obtain a prepolymer, and the reaction is continued to obtain the polyamide resin; the temperature of the heating treatment is 200℃, the absolute pressure is 1.7MPa, and the time is 55min; the temperature of the continued reaction is 275℃, the absolute pressure is 1.7MPa, and the time is 75min.

[0097] Example 2

[0098] This embodiment provides a polyamide resin, wherein the polyamide resin is prepared from hexamethylenediamine and adipic acid as starting materials to obtain polyhexamethylene adipamide;

[0099] Based on polyamide resin, the polyamide resin comprises 2 wt% of a first functional monomer, 0.5 wt% of a second functional monomer, and 0.1 wt% of a molecular weight regulator;

[0100] The first functional monomer is caprolactam; the second functional monomer is 2-vinyl terephthalic acid; and the molecular weight regulator is 2-ethylhexylamine.

[0101] The preparation method of the polyamide resin includes the following steps:

[0102] (1) A premixed solution is obtained by mixing nylon 66 salt solution, first functional monomer solution and second functional monomer solution according to the formula amount; the nylon 66 salt solution is a mixed solution of hexamethylenediamine and adipic acid, with a pH value of 7 and a mass concentration of 45 wt%; the first functional monomer solution is formed by salting the first functional monomer and adipic acid, with a pH value of 7 and a mass concentration of 50 wt%; the second functional monomer solution is formed by salting the second functional monomer and hexamethylenediamine, with a pH value of 7 and a mass concentration of 50 wt%.

[0103] (2) The premixed solution obtained in step (1) is evaporated and concentrated to obtain a polyamide salt solution with a mass concentration of 70 wt%; the evaporation and concentration temperature is 145°C and the absolute pressure is 0.2 MPa; the molecular weight regulator is mixed with the premixed solution during the concentration and evaporation process;

[0104] (3) The polyamide salt solution obtained in step (2) is heated to obtain a prepolymer, and the reaction is continued to obtain the polyamide resin; the temperature of the heating treatment is 190°C, the absolute pressure is 1.5MPa, and the time is 60min; the temperature of the continued reaction is 270°C, the absolute pressure is 1.5MPa, and the time is 80min.

[0105] Example 3

[0106] This embodiment provides a polyamide resin, wherein the polyamide resin is prepared from hexamethylenediamine and adipic acid as starting materials to obtain polyhexamethylene adipamide;

[0107] Based on polyamide resin, the polyamide resin comprises 10 wt% of a first functional monomer, 1.5 wt% of a second functional monomer, and 0.05 wt% of a molecular weight regulator;

[0108] The first functional monomer is caprolactam; the second functional monomer is 2-vinyl terephthalic acid; and the molecular weight regulator is 2-ethylhexylamine.

[0109] The preparation method of the polyamide resin includes the following steps:

[0110] (1) A premixed solution is obtained by mixing nylon 66 salt solution, first functional monomer solution and second functional monomer solution according to the formula amount; the nylon 66 salt solution is a mixed solution of hexamethylenediamine and adipic acid, with a pH value of 7.7 and a mass concentration of 53 wt%; the first functional monomer solution is formed by salting the first functional monomer and adipic acid, with a pH value of 7.2 and a mass concentration of 60 wt%; the second functional monomer solution is formed by salting the second functional monomer and hexamethylenediamine, with a pH value of 7.3 and a mass concentration of 60 wt%.

[0111] (2) The premixed solution obtained in step (1) is evaporated and concentrated to obtain a polyamide salt solution with a mass concentration of 75 wt%; the evaporation and concentration temperature is 150°C and the absolute pressure is 0.3 MPa; the molecular weight regulator is mixed with the premixed solution during the concentration and evaporation process;

[0112] (3) The polyamide salt solution obtained in step (2) is heated to obtain a prepolymer, and the reaction is continued to obtain the polyamide resin; the temperature of the heating treatment is 200℃, the absolute pressure is 1.7MPa, and the time is 55min; the temperature of the continued reaction is 275℃, the absolute pressure is 1.7MPa, and the time is 75min.

[0113] Example 4

[0114] This embodiment provides a polyamide resin, which is the same as that in Example 1 except that the first functional monomer is 2-methylpentanediamine.

[0115] Example 5

[0116] This embodiment provides a polyamide resin, except that the first functional monomer is isopropylhexanediamine and the amount of the second monomer added is 3 wt%, and the rest are the same as in Example 1.

[0117] Example 6

[0118] This embodiment provides a polyamide resin, which is the same as that in Example 1 except that the first functional monomer is 2-methylglutaric acid.

[0119] Example 7

[0120] This embodiment provides a polyamide resin, which is the same as that in Example 1 except that the first functional monomer is isopropyl adipic acid.

[0121] Example 8

[0122] This embodiment provides a polyamide resin, which is the same as that in Example 1 except that the second functional monomer is furan dicarboxylic acid.

[0123] Example 9

[0124] This embodiment provides a polyamide resin, which is the same as that in Example 1 except that the second functional monomer is diethyltoluenediamine.

[0125] Example 10

[0126] This embodiment provides a polyamide resin, which is the same as that in Example 1 except that the molecular weight regulator is 2-methylpropylamine.

[0127] Example 11

[0128] This embodiment provides a polyamide resin, which is the same as that in Example 1 except that the molecular weight regulator is n-hexylamine.

[0129] Example 12

[0130] This embodiment provides a polyamide resin, wherein the polyamide resin is prepared from hexamethylenediamine and adipic acid as starting materials to obtain polyhexamethylene adipamide;

[0131] Based on polyamide resin, the polyamide resin comprises 5 wt% of a first functional monomer and 1.5 wt% of a second functional monomer;

[0132] The first functional monomer is caprolactam, and the second functional monomer is 2-vinyl terephthalic acid;

[0133] The preparation method of the polyamide resin includes the following steps:

[0134] (1) A premixed solution is obtained by mixing nylon 66 salt solution, first functional monomer solution and second functional monomer solution according to the formula amount; the nylon 66 salt solution is a mixed solution of hexamethylenediamine and adipic acid, with a pH value of 7.7 and a mass concentration of 53 wt%; the first functional monomer solution is formed by salting the first functional monomer and adipic acid, with a pH value of 7.2 and a mass concentration of 60 wt%; the second functional monomer solution is formed by salting the second functional monomer and hexamethylenediamine, with a pH value of 7.3 and a mass concentration of 60 wt%.

[0135] (2) The premixed solution obtained in step (1) is evaporated and concentrated to obtain a polyamide salt solution with a mass concentration of 75 wt%; the temperature of the evaporation and concentration is 150°C and the absolute pressure is 0.3 MPa;

[0136] (3) The polyamide salt solution obtained in step (2) is heated to obtain a prepolymer, and the reaction is continued to obtain the polyamide resin; the temperature of the heating treatment is 200℃, the absolute pressure is 1.7MPa, and the time is 55min; the temperature of the continued reaction is 275℃, the absolute pressure is 1.7MPa, and the time is 75min.

[0137] Comparative Example 1

[0138] This comparative example provides a polyamide resin, wherein the polyamide resin is prepared from hexamethylenediamine and adipic acid as starting materials to obtain polyhexamethylene adipamide;

[0139] Based on polyamide resin, the polyamide resin comprises 5 wt% of a first functional monomer and 0.08 wt% of a molecular weight regulator;

[0140] The first functional monomer is caprolactam; the molecular weight regulator is 2-ethylhexylamine.

[0141] The preparation method of the polyamide resin includes the following steps:

[0142] (1) Mix nylon 66 salt solution and first functional monomer solution according to the formula to obtain a premixed solution; the nylon 66 salt solution is a mixed solution of hexamethylenediamine and adipic acid, with a pH value of 7.7 and a mass concentration of 53wt%; the first functional monomer solution is formed by the salt formation of the first functional monomer and adipic acid, with a pH value of 7.2 and a mass concentration of 60wt%.

[0143] (2) The premixed solution obtained in step (1) is evaporated and concentrated to obtain a polyamide salt solution with a mass concentration of 75 wt%; the evaporation and concentration temperature is 150°C and the absolute pressure is 0.3 MPa; the molecular weight regulator is mixed with the premixed solution during the concentration and evaporation process;

[0144] (3) The polyamide salt solution obtained in step (2) is heated to obtain a prepolymer, and the reaction is continued to obtain the polyamide resin; the temperature of the heating treatment is 200℃, the absolute pressure is 1.7MPa, and the time is 55min; the temperature of the continued reaction is 275℃, the absolute pressure is 1.7MPa, and the time is 75min.

[0145] Comparative Example 2

[0146] This comparative example provides a polyamide resin, wherein the polyamide resin is prepared from hexamethylenediamine and adipic acid as starting materials to obtain polyhexamethylene adipamide;

[0147] Based on polyamide resin, the polyamide resin comprises 1.5 wt% of a second functional monomer and 0.08 wt% of a molecular weight regulator;

[0148] The second functional monomer is 2-vinyl terephthalic acid; the molecular weight regulator is 2-ethylhexylamine.

[0149] The preparation method of the polyamide resin includes the following steps:

[0150] (1) Mix nylon 66 salt solution and second functional monomer solution according to the formula to obtain a premixed solution; the nylon 66 salt solution is a mixed solution of hexamethylenediamine and adipic acid, with a pH value of 7.7 and a mass concentration of 53wt%; the second functional monomer solution is formed by the second functional monomer and hexamethylenediamine forming a salt, with a pH value of 7.3 and a mass concentration of 60wt%.

[0151] (2) The premixed solution obtained in step (1) is evaporated and concentrated to obtain a polyamide salt solution with a mass concentration of 75 wt%; the evaporation and concentration temperature is 150°C and the absolute pressure is 0.3 MPa; the molecular weight regulator is mixed with the premixed solution during the concentration and evaporation process;

[0152] (3) The polyamide salt solution obtained in step (2) is heated to obtain a prepolymer, and the reaction is continued to obtain the polyamide resin; the temperature of the heating treatment is 200℃, the absolute pressure is 1.7MPa, and the time is 55min; the temperature of the continued reaction is 275℃, the absolute pressure is 1.7MPa, and the time is 75min.

[0153] Performance testing

[0154] (1) Polyamide fibers were prepared by melt spinning of the polyamide resins provided in Examples 1-12 and Comparative Examples 1-2. The spinning temperature was 290℃ and the spinning speed was 4000m / min. The fiber specifications were 0.45dpf.

[0155] The viscosity of the polyamide resins provided in Examples 1-12 and Comparative Examples 1-2 was measured using the sulfuric acid method. The full roll rate and fiber strength of the corresponding polyamide fibers were also tested. The full roll rate was measured by comparing the actual number of full rolls within a specified roll-down time with the theoretical number of full rolls. The fiber strength was tested using an electronic tensile tester. The results are shown in Table 1.

[0156] Table 1

[0157] Viscosity Full roll rate (%) Fiber strength (g / d) Example 1 2.56 98 6.3 Example 2 2.58 97.5 5.8 Example 3 2.51 98 5.5 Example 4 2.56 98 5.9 Example 5 2.55 97 6.4 Example 6 2.56 97 5.9 Example 7 2.55 98 5.8 Example 8 2.53 98 5.7 Example 9 2.55 98 5.8 Example 10 2.52 95 5.7 Example 11 2.53 95 5.8 Example 12 2.48 94 5.7 Comparative Example 1 2.54 93 5.2 Comparative Example 2 2.53 90 5.6

[0158] (2) In the process of preparing the polyamide resin provided in Examples 1 and 4, the titanium dioxide suspension was mixed with the premixed liquid in the evaporation and concentration in step (2). In Example 1, the amount of titanium dioxide added was 0.3%, and in Example 4, the amount of titanium dioxide added was 1.5%. Then, the obtained polyamide resin was used to prepare semi-dull and dull polyamide fibers by melt spinning. The spinning temperature was 290°C, the spinning speed was 4000 m / min, and the fiber specification was 0.45 dpf.

[0159] The raw materials for preparing the titanium dioxide suspension, by weight, include: 37.5 parts titanium dioxide, 0.065 parts potassium phosphate dispersant, and 100 parts solvent.

[0160] The potassium phosphate dispersant is potassium tripolyphosphate, and the solvent is demineralized water.

[0161] The preparation method of the titanium dioxide suspension includes the following steps:

[0162] (1) Mix titanium dioxide, potassium phosphate dispersant and solvent according to the formula amount, and pre-disperse at 18°C ​​for 30 min to obtain a pre-dispersed liquid;

[0163] (2) Grinding step (1) yields the pre-dispersed liquid, which is then used to obtain the grinding liquid;

[0164] (3) The grinding liquid obtained in step (2) was allowed to stand at 20°C for 25 hours to settle, and the resulting upper liquid was the titanium dioxide suspension.

[0165] The full roll rate and fiber strength of the corresponding matte polyamide fibers were tested. The full roll rate was measured by comparing the actual number of full rolls with the theoretical number of full rolls within a specified drop time. The fiber strength was tested using an electronic tensile tester. The results are shown in Table 2.

[0166] Table 2

[0167] Full roll rate (%) Fiber strength (g / d) Example 1 98 6.1 Example 4 98 5.7

[0168] In summary, the polyamide resin obtained by this invention exhibits good spinnability and high fiber strength when used to prepare polyamide fibers. It is suitable for producing fibers with a single fiber fineness of less than 0.5 dpf. The production conditions are stable and the product indicators are excellent when the spinning speed is above 4000 m / min. The polyamide resin obtained by this invention is also suitable for preparing matte polyamide fibers.

[0169] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A polyamide resin characterized in that, The polyamide resin is prepared from hexamethylene diamine and adipic acid; The polyamide resin further comprises 2wt% or more of the first functional monomer and 0.5-3wt% of the second functional monomer, and the first functional monomer is less than 10wt% based on the polyamide resin; The first functional monomer comprises any one or a combination of at least two of C4-C6 lactam, C4-C10 branched diamine or C4-C10 branched diacid; The C4-C6 lactam comprises valerolactam and / or caprolactam; The C4-C10 branched diamine comprises any one or a combination of at least two of methylpentanediamine, ethylpentanediamine, isopropylpentanediamine, dimethylpentanediamine, methylhexanediamine, ethylhexanediamine, isopropylhexanediamine or dimethylhexanediamine; The C4-C10 branched diacid comprises any one or a combination of at least two of methylglutaric acid, ethylglutaric acid, isopropylglutaric acid, dimethylglutaric acid, methyladipic acid, ethyladipic acid, isopropyladipic acid or dimethyladipic acid; The second functional monomer comprises any one or a combination of at least two of furandicarboxylic acid, 2-vinylterephthalic acid or diethyltoluene diamine.

2. The polyamide resin according to claim 1, characterized in that, The polyamide resin further comprises 0.001-0.2wt% of a molecular weight regulator based on the polyamide resin.

3. The polyamide resin according to claim 2, characterized in that, The polyamide resin comprises 0.05-0.1wt% of a molecular weight regulator based on the polyamide resin.

4. The polyamide resin according to claim 2, characterized in that, The molecular weight regulator is a branched monoamine with a carbon backbone of C4-C10.

5. The polyamide resin according to claim 4, characterized in that, The molecular weight regulator is 2-ethylhexylamine and / or 2-propyldecylamine.

6. A method for producing the polyamide resin according to any one of claims 1 to 5, characterized by, The preparation method comprises the following steps: (1) mixing nylon 66 salt solution, first functional monomer solution and second functional monomer solution according to the formula to obtain a premix; (2) evaporating and concentrating the premix obtained in step (1) to obtain a polyamide salt solution; (3) treating the polyamide salt solution obtained in step (2) at an elevated temperature to obtain a prepolymer, and continuing the reaction to obtain the polyamide resin.

7. The production method according to claim 6, wherein The nylon 66 salt solution in step (1) is a mixed solution of hexamethylene diamine and adipic acid.

8. The preparation method according to claim 7, characterized in that, The pH value of the nylon 66 salt solution in step (1) is 7-8, and the mass concentration is 45-55wt%.

9. The preparation method according to claim 6, characterized in that, The first functional monomer solution in step (1) is formed by salification of the first functional monomer with adipic acid and / or hexamethylene diamine; the pH value of the first functional monomer solution is 7-8, and the mass concentration is 50-65wt%.

10. The method of claim 6, wherein, The second functional monomer solution in step (1) is formed by salification of the second functional monomer with adipic acid and / or hexamethylene diamine; the pH value of the second functional monomer solution is 7-8, and the mass concentration is 50-65wt%.

11. The preparation method according to claim 6, characterized in that, The evaporation and concentration temperature in step (2) is 145-155℃.

12. The method of claim 6, wherein, The evaporation and concentration absolute pressure in step (2) is 0.2-0.5MPa.

13. The method of claim 6, wherein the method further comprises, The mass concentration of the polyamide salt solution in step (2) is 70-80wt%.

14. The method of claim 6, wherein, The temperature of the elevated temperature treatment in step (3) is 190-210℃, the absolute pressure is 1.5-2.0MPa, and the time is 50-60min.

15. The method of claim 6, wherein the method further comprises, The temperature of the continued reaction in step (3) is 270-280℃, the absolute pressure is 1.5-2.0 MPa, and the time is 70-80 min.

16. The method of claim 6, wherein, The preparation method comprises the following steps: (1) mixing a nylon 66 salt solution, a first functional monomer solution, and a second functional monomer solution according to the formula amount to obtain a premix solution; the nylon 66 salt solution is a mixed solution of hexanediamine and adipic acid, has a pH value of 7-8, and has a mass concentration of 45-55 wt%; the first functional monomer solution is formed by salification of a first functional monomer with adipic acid and / or hexanediamine, has a pH value of 7-8, and has a mass concentration of 50-65 wt%; and the second functional monomer solution is formed by salification of a second functional monomer with adipic acid and / or hexanediamine, has a pH value of 7-8, and has a mass concentration of 50-65 wt%; (2) evaporating and concentrating the premix solution obtained in step (1) to obtain a polyamide salt solution with a mass concentration of 70-80 wt%; the evaporation and concentration are performed at a temperature of 145-155℃ and an absolute pressure of 0.2-0.5 MPa; (3) warming and treating the polyamide salt solution obtained in step (2) to obtain a prepolymer, and continuing the reaction to obtain the polyamide resin; the warming and treating are performed at a temperature of 190-210℃, an absolute pressure of 1.5-2.0 MPa, and a time of 50-60 min; and the temperature of the continued reaction is 270-280℃, the absolute pressure is 1.5-2.0 MPa, and the time is 70-80 min.

17. A polyamide fiber characterized in that, The polyamide fiber is prepared from the polyamide resin according to any one of claims 1-5. The polyamide fiber has a single-fiber fineness of ≤0.5 dpf.