CN118085272A - Short-process polyamide synthesis method - Google Patents

Short-process polyamide synthesis method Download PDF

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Publication number
CN118085272A
CN118085272A CN202410529700.3A CN202410529700A CN118085272A CN 118085272 A CN118085272 A CN 118085272A CN 202410529700 A CN202410529700 A CN 202410529700A CN 118085272 A CN118085272 A CN 118085272A
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diamine
acid
dicarboxylic acid
polyamide
short
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陆一神
吉鹏
吴宇豪
徐锦龙
王华平
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Jiangsu New Vision Advanced Functional Fiber Innovation Center Co ltd
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Jiangsu New Vision Advanced Functional Fiber Innovation Center Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
    • C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
    • C08G69/26—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from polyamines and polycarboxylic acids
    • C08G69/28—Preparatory processes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
    • C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
    • C08G69/26—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from polyamines and polycarboxylic acids
    • C08G69/265—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from polyamines and polycarboxylic acids from at least two different diamines or at least two different dicarboxylic acids

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Polyamides (AREA)

Abstract

The invention belongs to the technical field of polymer preparation, and relates to a short-process polyamide synthesis method. The synthesis method comprises the following steps: diamine A, dicarboxylic acid A and carrier materials are used as main raw materials, and the pre-polymerization and polycondensation reactions are directly carried out to prepare polyamide; the carrier material is oligomer generated by the reaction of diamine B and dicarboxylic acid B; the molar ratio of diamine A to dicarboxylic acid A is 1:1; the addition amount of the carrier substance is 0.5-49.9% of the total mass of diamine A and dicarboxylic acid A. According to the short-process polyamide synthesis method, the oligomer formed by the dibasic acid and the diamine is introduced as a carrier material to replace a solvent in a salifying step in the existing polyamide synthesis process, so that the salifying step and the prepolymerization step can be combined into one, and meanwhile, the salifying and concentrating steps in the existing process are omitted, and the preparation process is greatly shortened; on the other hand, the concentration and solvent removal steps are reduced, so that the heat consumption is greatly reduced, and the cost is reduced.

Description

Short-process polyamide synthesis method
Technical Field
The invention belongs to the technical field of polymer preparation, and relates to a short-process polyamide synthesis method.
Background
The polyamide has the excellent characteristics of light weight, high strength, wear resistance, low temperature resistance, crease resistance, pilling resistance, good touch feeling and the like, and is widely applied to the aspects of fibers, plastics and the like. Among them, polyamides obtained by polycondensation of diamines and dicarboxylic acids are generally called AABB type polyamides. Currently, the AABB type polyamide is generally prepared from diamine and dicarboxylic acid through multiple procedures such as salifying, concentrating, prepolymerizing, pressure relief, polycondensation and the like.
For example, patent CN114106319B discloses a method for continuously preparing polyamide with low gel content and narrow molecular weight distribution and a product thereof, the method of the patent comprises a salifying stage, a melt polymerization stage and a solid phase polymerization stage, wherein the salifying stage takes diacid and diamine as raw materials, takes pure water as a solvent, and obtains nylon salt solution through salifying reaction, and the concentration and the amine acid ratio of the nylon salt solution are regulated and controlled on line by an on-line potentiometric titration control system.
For another example, patent CN115806668a discloses a copolymer, a preparation method thereof, and a method for reducing polyamide melt gel, the method of the patent comprises the steps of: mixing diamine, dibasic acid and water to prepare a polyamide salt solution; carrying out copolymerization reaction on the polyamide salt solution to obtain a copolymer melt; and (3) melting and discharging the copolymer melt, water-cooling and granulating.
For another example, patent CN110857331B discloses a copolymer comprising polyamide 56 and a process for its preparation, the process of which comprises the steps of: preparing a mixed solution comprising a polyamide 56 salt; polymerizing the mixed solution to obtain a copolymer; one or more of caprolactam, caprolactam ring-opened product and PA6 polymer are added in any or all of the preceding steps.
However, the preparation methods of the above prior arts all have the following problems: (1) The process flow is long, a large amount of equipment is required to be matched, and the production cost is high; (2) A large amount of water is introduced in the salifying stage to ensure that the polyamide salt is completely dissolved, and a large amount of heat is consumed in the concentrating stage to remove water, so that a large amount of energy is wasted, and the production cost is increased.
Therefore, the development of a short-process polyamide synthesis method is of great practical significance.
Disclosure of Invention
The invention aims to solve the problems existing in the prior art and provides a short-process polyamide synthesis method.
In order to achieve the above purpose, the invention adopts the following technical scheme:
A short-process polyamide synthesis method takes diamine A, dicarboxylic acid A and carrier substances as main raw materials, and directly performs prepolymerization and polycondensation reaction to prepare polyamide without salifying reaction, so that the salifying and concentrating processes and solvent use in the prior art are avoided, the polyamide synthesis process is greatly shortened, and the energy consumption is greatly reduced;
the carrier material is oligomer generated by the reaction of diamine B and dicarboxylic acid B;
The molar ratio of diamine A to dicarboxylic acid A is 1:1; if the equimolar ratio of diamine A to dicarboxylic acid A is not controlled, the addition of the diamine A and dicarboxylic acid A is easy to cause excessive monocarboxylic acid or amino, so that end capping occurs in the polymerization process, and the preparation of a polymer with high molecular weight is not facilitated;
The addition amount of the carrier substance is 0.5-49.9% of the total mass of diamine A and dicarboxylic acid A.
As a preferable technical scheme:
The short-process polyamide synthesis method has the advantage that the number average molecular weight of the carrier substance is 3000-5000. If the molecular weight is too high, the viscosity is too high, which is unfavorable for the movement of the monomer in the melt and affects the molecular weight and the distribution of the obtained polymer; when the molecular weight is too low, the viscosity is too low, and the monomer is easily volatilized to cause the molar ratio to be destroyed, so that the problems of no removal of the molecular weight and widening of the molecular weight distribution are caused.
In the method for synthesizing the short-process polyamide, diamine A and diamine B are independently selected from more than one of butanediamine, pentanediamine, hexanediamine, heptanediamine, octanediamine, nonanediamine, decanediamine and long-carbon-chain diamine with eleven to eighteen carbon atoms, and dicarboxylic acid A and dicarboxylic acid B are independently selected from more than one of terephthalic acid, isophthalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid and long-carbon-chain dicarboxylic acid with eleven to eighteen carbon atoms.
The short-process polyamide synthesis method comprises the following specific steps:
(1) Pre-polymerization reaction;
Diamine A and dicarboxylic acid A are added step by step (diamine A can be added firstly, dicarboxylic acid A can be added firstly, but the diamine A and the dicarboxylic acid A cannot be added together, because the problem of high reactivity of acid and amine exists when the diamine A and the dicarboxylic acid A are added together, the diamine is volatilized due to easy reaction and heat release in the mixing process outside a kettle), the diamine A and the dicarboxylic acid A react for 30-50 min under the condition of 0.5-1.5 MPa and 180-260 ℃ in the atmosphere of nitrogen or carbon dioxide, then the pressure is relieved to normal pressure within 10-40 min, and the reaction is stopped when the water yield reaches more than 98.5% of the theoretical water yield, so as to obtain a prepolymer;
The trace substances are one or more of caprolactam, enantholactam, caprylic lactam, pelargonamide, capric lactam, lactam with eleven to fifteen carbon atoms, aminocaproic acid, aminoheptanoic acid, aminocaprylic acid, aminononanoic acid, aminodecanoic acid and amino acid with eleven to fifteen carbon atoms;
The addition amount of trace substances is not more than 0.5wt% based on the total mass of diamine A, dicarboxylic acid A and carrier substances;
The trace substances added in the invention play a role in regulating the melting point and the fluidity. For example, in the prior art for producing polyamide 66 by salt-forming-concentrating-prepolymerizing-polycondensation processes, the addition of caprolactam can adjust the melting point, usually in an amount of about 5% by weight, and cannot be said to be a micro addition. The addition amount in the prior art is more because the water content of the system is more, caprolactam is easy to discharge along with water vapor in the concentration and prepolymerization process, and the effective concentration is reduced. The invention avoids the use of solvent water, so that the effective concentration of amino acid generated by ring opening of caprolactam is improved, and the purpose can be achieved only by adding trace amount of the amino acid (if trace amount of substances are not amides such as caprolactam, but the amino acid is not ring opening process).
If no carrier substance is introduced, the prepolymerization time is usually 60-180 min, but the introduction of the carrier substance accelerates the dissolution rate of diamine A and dicarboxylic acid A in a reaction system, and simultaneously, the invention avoids introducing a large amount of solvent, water generated by the reaction of diamine A and dicarboxylic acid A can be rapidly discharged into gas phase from melt, the reaction is promoted to move towards the polymerization direction, and the time required by the prepolymerization reaction is greatly reduced by the synergistic effect of the diamine A and dicarboxylic acid A;
The invention adds catalyst to accelerate reaction rate and shorten reaction time, thereby reducing side reaction. The invention uses thermal oxygen stabilizer to prevent degradation and color deterioration caused by thermal oxygen. The invention controls the prepolymerization temperature to 180-260 ℃ because the prepolymerization reaction is an endothermic reaction, and too high temperature can accelerate the prepolymerization reaction rate, but the polyamide is also easy to be thermally degraded, and too low temperature can not meet the heat requirements of the prepolymerization reaction and the dissolution process; the pre-polymerization process has a certain positive pressure, and the pressure is controlled to be 0.5-1.5 MPa, because the byproduct in the pre-polymerization process is small molecular water; in addition, the boiling point of the monomer can be increased by a certain positive pressure, and the monomer is prevented from escaping into a gas phase to destroy the equimolar ratio; the pressure required in the pre-polymerization stage is slightly lower than that of the existing conventional process (1.7-1.9 MPa), so that the method can be directly carried out on the existing device, and the service cycle of equipment components can be prolonged; the pressure of the present invention is lower than the prior art because of the large amount of water required in the prior art, which generates high pressure at high temperature; the lower pressure of the present invention is because no water is used and only a small amount of water produced by the polycondensation reaction generates pressure at high temperature, and thus the pressure of the present invention is lower than that of the prior art.
(2) Performing polycondensation reaction;
reacting the prepolymer obtained in the step (1) for 10-30 min under the conditions of minus 0.100 to minus 0.030MPa and 200-280 ℃ to obtain polyamide;
The temperature of the polycondensation reaction is controlled at 200-280 ℃, and the temperature is too low to react, so that side reactions are aggravated when the temperature is too high, the color of the obtained polyamide is poor, the molecular weight distribution is widened, and the gel content is increased; the polycondensation pressure is controlled at-0.100 to-0.030 MPa, because the polycondensation reaction rate of the polyamide is high, the low-viscosity small molecules are quickly moved due to the excessively high vacuum degree, so that the reaction rate is further improved to cause 'bursting', the production cost is increased, the low-viscosity small molecules are difficult to remove from a system due to the excessively low vacuum degree, the reaction time is increased, the side reaction is increased to cause the color of the formed polyamide to be poor, the gel content is increased, and the molecular weight distribution is widened; the polycondensation time is controlled to be 10-30 min, and the required viscosity cannot be achieved due to the fact that the polycondensation time is too short, and the formed polyamide is poor in color, increased in gel content and widened in molecular weight distribution due to the fact that side reactions are increased due to the fact that the polycondensation time is too long.
In the short-process polyamide synthesis method, the polymerization degree of the prepolymer obtained in the step (1) is 10-25.
As the catalyst in the step (1), the catalyst is more than one of potassium phosphite, sodium phosphite, magnesium phosphite, aluminum phosphite, calcium phosphite, barium phosphite, zinc phosphite, potassium hypophosphite, sodium hypophosphite, magnesium hypophosphite, calcium hypophosphite, zinc hypophosphite, aluminum hypophosphite and barium hypophosphite, and the thermal oxygen stabilizer is more than one of antioxidant 1010, antioxidant 1096, antioxidant 168, triphenyl phosphite and triphenyl phosphate.
According to the short-process polyamide synthesis method, the total mass of diamine A, dicarboxylic acid A and carrier substances is taken as a reference, the addition amount of trace substances is 0.1-0.5wt%, the addition amount of catalysts is 0.001-0.05wt%, and the addition amount of thermal oxygen stabilizers is 0.001-0.05wt%.
According to the short-process polyamide synthesis method, the relative viscosity of the polyamide prepared in the step (2) is 2.2-2.9, the yellow index is less than or equal to-1, the molecular weight distribution range is 1.2-2, and the gel particle content is not higher than 0.1wt%.
A short-process polyamide synthesis process as described above, the polyamide can be used to prepare polyamide POY, FDY, DTY or short fibers (fiber or engineering plastics field) by drying.
The mechanism of the invention is as follows:
The existing polyamide synthesis process needs to add dibasic acid and diamine into a solvent to form salt, then concentrate the salt solution, pre-polymerize the salt solution under high pressure to form an oligomer, and then discharge the pressure to normal pressure or slight negative pressure to perform polycondensation reaction to form polyamide. The problems are that the polymerization time is long, side reaction is easy to occur, and the final polymer has poor color, wide molecular weight distribution and poor processability; and the introduction and removal process of the solvent consumes a large amount of heat, the production process flow is long, the equipment requirement is complex, and the production cost is high.
Aiming at the problems, under the condition of strictly controlling the molar ratio of acid to amine, the carrier material is introduced to replace the solvent to be used as a bed for the reaction of the dibasic acid and the diamine (namely diamine A and dicarboxylic acid A), and the diamine A and the dicarboxylic acid A can be quickly dissolved and reacted, so that the pre-polymerization reaction is quickened, the time for reaching a homogeneous system is shortened, and the occurrence of side reaction is facilitated; and secondly, the heat released by the reaction of the diamine A and the dicarboxylic acid A can be directly used for maintaining the prepolymerization reaction, so that the supply of external heat is reduced, and compared with the prior art, the method omits the steps of salifying and concentrating, shortens the process flow and reduces the energy consumption.
In the prior art, the salt forming step is carried out firstly, the solvent is used as a bed for the reaction of the dibasic acid and the diamine, because the diamine is not easy to volatilize during polymerization after the salt forming, the diamine A is still not easy to volatilize without the steps of salt forming and the like, because the diamine A and the dicarboxylic acid A in the system have high reaction activity and quickly react to generate the salt, the salt is quickly dissolved in a carrier material which also consists of an amide bond to carry out dehydration and polycondensation reaction, and the water generated by the reaction is quickly gasified to generate pressure, so that the volatilization of the diamine A is inhibited; in addition, diamine a will dissolve in the carrier material, and the evaporation rate of diamine a from the carrier material is significantly less than from water, also inhibiting its evaporation to some extent.
The beneficial effects are that:
(1) According to the short-process polyamide synthesis method, the oligomer formed by the dibasic acid and the diamine is introduced as a carrier material to replace a solvent in a salifying step in the existing polyamide synthesis process, so that the salifying step and the prepolymerization step can be combined into one, and meanwhile, the salifying and concentrating steps in the existing process are omitted, and the preparation process is greatly shortened; on the other hand, as the steps of concentrating and removing the solvent are reduced, the heat consumption is greatly reduced, and the cost is reduced;
(2) According to the short-process polyamide synthesis method, the carrier material is used as a bed for the prepolymerization reaction, so that the purpose of dynamics reinforcement is achieved, the reaction is faster, the reaction time is shortened compared with the prior art, the side reaction is reduced, the color of the formed polyamide is better, the molecular weight distribution is narrower, and the processability is better;
(3) The polyamide obtained by the method has the relative viscosity of 2.2-2.9, the yellow index of less than or equal to-1 and the molecular weight distribution range of 1.2-2, and can be used for preparing polyamide POY, FDY, DTY or short fibers (in the field of fibers or engineering plastics).
Detailed Description
The application is further described below in conjunction with the detailed description. It is to be understood that these examples are illustrative of the present application and are not intended to limit the scope of the present application. Furthermore, it should be understood that various changes and modifications can be made by one skilled in the art after reading the teachings of the present application, and such equivalents are intended to fall within the scope of the application as defined in the appended claims.
The following are test methods for the relevant performance indicators in each of the examples and comparative examples:
Relative viscosity: the test was performed with reference to the 96% (mass fraction) sulfuric acid test standard in GB/T12006.1-2009.
Yellow index: the test was performed with reference to the GB/T39822-2021 standard.
Molecular weight distribution range: testing by gel chromatography; wherein the testing instrument is Agilent 1260 type gel chromatograph, the chromatographic column is Agilent HFIP series, the mobile phase is hexafluoroisopropanol+0.02M sodium trifluoroacetate, and the testing temperature is 40deg.C.
Gel particle content: the test is carried out by adopting a formic acid dissolution method, a formic acid solution with the mass fraction of 90% is used for dissolving the sample, undissolved parts are filtered and separated, and the undissolved parts are weighed and calculated after drying.
Example 1
A short-process polyamide synthesis method comprises the following specific steps:
(1) Preparing raw materials;
diamine a: a mixture of decanediamine and nonanediamine in a molar ratio of 1:1;
dicarboxylic acid a: a mixture of azelaic acid and pimelic acid in a molar ratio of 1:1;
diamine B: butanediamine;
Dicarboxylic acid B: a mixture of undecanedicarboxylic acid (CAS number 1852-04-6) and glutaric acid in a molar ratio of 1:1;
trace substances: a mixture of caprolactam and aminononanoic acid in a mass ratio of 1:1;
Catalyst: a mixture of calcium hypophosphite, aluminum hypophosphite and zinc phosphite in a mass ratio of 1:1:1;
thermal oxygen stabilizer: antioxidant 1010, manufacturer basf, germany;
(2) Diamine B and dicarboxylic acid B with a molar ratio of 1:1 are reacted at 230 ℃ to obtain a carrier material with a number average molecular weight of 3000;
(3) Adding diamine A and dicarboxylic acid A into a reaction system consisting of a carrier substance, a trace substance, a catalyst and a thermal oxygen stabilizer in steps, reacting for 30min under the condition of 0.5MPa and 230 ℃ in a nitrogen atmosphere, then releasing pressure to normal pressure within 10min, and stopping the reaction when the water yield reaches 98.5% of the theoretical water yield to obtain a prepolymer with the polymerization degree of 25;
Wherein, the mol ratio of diamine A to dicarboxylic acid A is 1:1; the addition amount of the carrier substance is 49.9 percent of the total mass of diamine A and dicarboxylic acid A; the addition amount of trace substances is 0.1wt percent, the addition amount of the catalyst is 0.005wt percent and the addition amount of the thermal oxygen stabilizer is 0.001wt percent based on the total mass of diamine A, dicarboxylic acid A and carrier substances;
(4) And (3) reacting the prepolymer obtained in the step (3) for 30min under the conditions of-0.1 MPa and 220 ℃ to obtain the polyamide.
The final polyamide has a relative viscosity of 2.9, a yellow index of-6, a molecular weight distribution of 1.8 and no gel particles.
Example 2
A short-process polyamide synthesis method comprises the following specific steps:
(1) Preparing raw materials;
diamine a: a mixture of butanediamine and heptanediamine in a molar ratio of 1:1;
Dicarboxylic acid a: a mixture of adipic acid and succinic acid in a molar ratio of 1:1;
Diamine B: a mixture of hexamethylenediamine and tridecane diamine in a molar ratio of 1:1;
Dicarboxylic acid B: a mixture of octadecadioic acid (CAS number 871-70-5) and terephthalic acid in a molar ratio of 1:1;
Trace substances: a mixture of caprylolactam, omega-undecanolactam and pelargonamide in a mass ratio of 1:1:1;
Catalyst: a mixture of calcium phosphite and aluminum phosphite in a mass ratio of 1:1;
Thermal oxygen stabilizer: antioxidant 1096, manufacturer basf, germany;
(2) Diamine B and dicarboxylic acid B with a molar ratio of 1.01:1 are reacted at 260 ℃ to obtain a carrier material with a number average molecular weight of 3500;
(3) Adding diamine A and dicarboxylic acid A into a reaction system consisting of a carrier substance, a trace substance, a catalyst and a thermal oxygen stabilizer in steps, reacting for 34min under the condition of 1.2MPa and 250 ℃ in a nitrogen atmosphere, then releasing pressure to normal pressure within 40min, and stopping the reaction when the water yield reaches 99.1% of the theoretical water yield to obtain a prepolymer with the polymerization degree of 10;
wherein, the mol ratio of diamine A to dicarboxylic acid A is 1:1; the addition amount of the carrier substance is 30% of the total mass of diamine A and dicarboxylic acid A; the addition amount of trace substances is 0.5wt percent, the addition amount of the catalyst is 0.05wt percent and the addition amount of the thermal oxygen stabilizer is 0.05wt percent based on the total mass of diamine A, dicarboxylic acid A and carrier substances;
(4) And (3) reacting the prepolymer obtained in the step (3) for 25min under the conditions of-0.05 MPa and 280 ℃ to obtain the polyamide.
The final polyamide had a relative viscosity of 2.3, a yellowness index of-2, a molecular weight distribution range of 2 and a gel particle content of 0.09wt%.
Comparative example 1
A polyamide synthesis process substantially as described in example 2, with the only differences: step (2) is not carried out, and no carrier material is added in step (3).
The final polyamide produced had a relative viscosity of 1.7, a yellowness index of 10, a molecular weight distribution range of 3.5 and a gel particle content of 10% by weight.
Compared with the comparative example 1, the relative viscosity is obviously reduced, the yellow index is obviously increased, the molecular weight distribution range is obviously widened, and the gel content is obviously increased, because the comparative example 1 is free from adding carrier substances, the viscosity of the system is lower during the reaction, the diffusion rate of diamine A in the system is fast, the pressure during the reaction is also low, diamine A is easy to escape from the reaction system to damage the molar ratio, and excessive carboxylic acid leads to end capping during the polymerization process, so that the molecular weight is low, and the relative viscosity is greatly reduced; the excessive carboxyl groups are easy to generate a ring reaction at high temperature to generate a large amount of cyclic ketone substances, the cyclic ketone substances can generate a large amount of gel through the crosslinking reaction with polyamide, and the large amount of gel also leads to the wide molecular weight distribution range; in addition, gels are often yellow or brown in color, resulting in a substantial increase in yellow index.
Example 3
A short-process polyamide synthesis method comprises the following specific steps:
(1) Preparing raw materials;
Diamine a:1, 11-undecanediamine;
Dicarboxylic acid a: a mixture of isophthalic acid and suberic acid in a molar ratio of 1:1;
Diamine B: a mixture of 1, 11-undecanediamine and heptanediamine in a molar ratio of 1:1;
dicarboxylic acid B: a mixture of isophthalic acid and suberic acid in a molar ratio of 1:1;
Trace substances: a mixture of decyllactam, ω -pentadecyllactam and aminocaproic acid in a mass ratio of 1:1:1;
Catalyst: a mixture of potassium phosphite, potassium hypophosphite and sodium phosphite in a mass ratio of 1:1:1;
thermal oxygen stabilizer: antioxidant 168, manufactured by basf, germany;
(2) Diamine B and dicarboxylic acid B with a molar ratio of 1.02:1 are reacted at 225 ℃ to obtain a carrier material with a number average molecular weight of 4500;
(3) Adding diamine A and dicarboxylic acid A into a reaction system consisting of a carrier substance, a trace substance, a catalyst and a thermal oxygen stabilizer in steps, reacting for 38min under the condition of 0.8MPa and 180 ℃ in a nitrogen atmosphere, then releasing pressure to normal pressure within 18min, and stopping the reaction when the water yield reaches 99% of the theoretical water yield to obtain a prepolymer with the polymerization degree of 16;
wherein, the mol ratio of diamine A to dicarboxylic acid A is 1:1; the addition amount of the carrier substance is 0.5% of the total mass of diamine A and dicarboxylic acid A; the addition amount of trace substances is 0.3wt percent, the addition amount of the catalyst is 0.02wt percent and the addition amount of the thermal oxygen stabilizer is 0.03wt percent based on the total mass of diamine A, dicarboxylic acid A and carrier substances;
(4) And (3) reacting the prepolymer obtained in the step (3) for 15min under the conditions of-0.03 MPa and 250 ℃ to obtain the polyamide.
The final polyamide has a relative viscosity of 2.6, a yellow index of-8, a molecular weight distribution of 1.5 and no gel particles.
Example 4
A short-process polyamide synthesis method comprises the following specific steps:
(1) Preparing raw materials;
diamine a: a mixture of 1, 18-octadecanediamine and hexamethylenediamine in a molar ratio of 1:1;
dicarboxylic acid a: a mixture of undecanedicarboxylic acid and glutaric acid in a molar ratio of 1:1;
diamine B: a mixture of nonylenediamine and decylenediamine in a molar ratio of 1:1;
Dicarboxylic acid B: a mixture of azelaic acid and sebacic acid in a molar ratio of 1:1;
trace substances: a mixture of omega-aminoundecanoic acid, aminodecanoic acid and enantholactam in a mass ratio of 1:1:1;
Catalyst: sodium hypophosphite;
thermal oxygen stabilizer: triphenyl phosphite;
(2) Diamine B and dicarboxylic acid B with a molar ratio of 1.03:1 are reacted at 220 ℃ to obtain a carrier material with a number average molecular weight of 4500;
(3) Adding diamine A and dicarboxylic acid A into a reaction system consisting of a carrier substance, a trace substance, a catalyst and a thermal oxygen stabilizer in steps, reacting for 41min under the condition of 1MPa and 220 ℃ in a carbon dioxide atmosphere, then releasing pressure to normal pressure within 32min, and stopping the reaction when the water yield reaches 99.5% of the theoretical water yield to obtain a prepolymer with the polymerization degree of 22;
Wherein, the mol ratio of diamine A to dicarboxylic acid A is 1:1; the addition amount of the carrier substance is 15% of the total mass of diamine A and dicarboxylic acid A; the addition amount of trace substances is 0.4wt percent, the addition amount of the catalyst is 0.03wt percent and the addition amount of the thermal oxygen stabilizer is 0.02wt percent based on the total mass of diamine A, dicarboxylic acid A and carrier substances;
(4) And (3) reacting the prepolymer obtained in the step (3) for 10min under the conditions of-0.04 MPa and 200 ℃ to obtain the polyamide.
The final polyamide has a relative viscosity of 2.2, a yellow index of-6, a molecular weight distribution of 1.2 and no gel particles.
Example 5
A short-process polyamide synthesis method comprises the following specific steps:
(1) Preparing raw materials;
diamine a: a mixture of pentamethylenediamine and tridecyldiamine in a molar ratio of 1:1;
dicarboxylic acid a: a mixture of terephthalic acid and sebacic acid in a molar ratio of 1:1;
Diamine B:1, 18-octadecanediamine;
Dicarboxylic acid B: pimelic acid;
trace substances: a mixture of aminoheptanoic acid, aminocaprylic acid and ω -aminopentadecanoic acid in a mass ratio of 1:1:1;
catalyst: a mixture of magnesium phosphite, zinc hypophosphite and barium phosphite in a mass ratio of 1:1:1;
Thermal oxygen stabilizer: triphenyl phosphate;
(2) Diamine B and dicarboxylic acid B with a molar ratio of 1.04:1 are reacted at 250 ℃ to obtain a carrier material with a number average molecular weight of 5000;
(3) Adding diamine A and dicarboxylic acid A into a reaction system consisting of a carrier substance, a trace substance, a catalyst and a thermal oxygen stabilizer in steps, reacting for 46min under the condition of 1.5MPa and 260 ℃ in a carbon dioxide atmosphere, then releasing pressure to normal pressure within 26min, and stopping the reaction when the water yield reaches 98.7% of the theoretical water yield to obtain a prepolymer with the polymerization degree of 11;
Wherein, the mol ratio of diamine A to dicarboxylic acid A is 1:1; the addition amount of the carrier substance is 20% of the total mass of diamine A and dicarboxylic acid A; the addition amount of trace substances is 0.5wt percent, the addition amount of the catalyst is 0.04wt percent and the addition amount of the thermal oxygen stabilizer is 0.04wt percent based on the total mass of diamine A, dicarboxylic acid A and carrier substances;
(4) And (3) reacting the prepolymer obtained in the step (3) for 10min under the conditions of-0.08 MPa and 270 ℃ to obtain the polyamide.
The final polyamide had a relative viscosity of 2.3, a yellowness index of-1, a molecular weight distribution range of 2 and a gel particle content of 0.1wt%.
Comparative example 2
A polyamide synthesis process substantially as described in example 5, with the only differences: in the step (3), the addition amount of the carrier substance is 0.3% of the total mass of diamine A and dicarboxylic acid A.
The final polyamide had a relative viscosity of 1.9, a yellowness index of 6, a molecular weight distribution range of 3.1 and a gel particle content of 3 wt.%.
Compared with the comparative example 2, the yellow index is obviously increased, the molecular weight distribution range is obviously widened, and the gel content is obviously increased, because the addition of carrier substances in the comparative example 2 is too little, the viscosity of the system is lower during the reaction, the diffusion rate of diamine A in the system is fast, the pressure during the reaction is also low, diamine A is easy to escape from the reaction system to damage the mole ratio, and excessive carboxylic acid leads to end capping during the polymerization, so that the molecular weight is low, and the relative viscosity is greatly reduced; the excessive carboxyl groups are easy to generate a ring reaction at high temperature to generate a large amount of cyclic ketone substances, the cyclic ketone substances can generate a large amount of gel through the crosslinking reaction with polyamide, and the large amount of gel also leads to the wide molecular weight distribution range; in addition, gels are often yellow or brown in color, resulting in a substantial increase in yellow index.
Example 6
A short-process polyamide synthesis method comprises the following specific steps:
(1) Preparing raw materials;
Diamine a: octanediamine;
dicarboxylic acid a: octadecadioic acid;
diamine B: a mixture of pentamethylenediamine and octanediamine in a molar ratio of 1:1;
Dicarboxylic acid B: a mixture of succinic and adipic acids in a molar ratio of 1:1;
trace substances: octalactam;
Catalyst: a mixture of barium hypophosphite and magnesium hypophosphite in a mass ratio of 1:1;
thermal oxygen stabilizer: a mixture of triphenyl phosphite and triphenyl phosphate in a mass ratio of 1:1;
(2) Diamine B and dicarboxylic acid B with a molar ratio of 1.05:1 are reacted at 220 ℃ to obtain a carrier material with a number average molecular weight of 4000;
(3) Adding diamine A and dicarboxylic acid A into a reaction system consisting of a carrier substance, a trace substance, a catalyst and a thermal oxygen stabilizer in steps, reacting for 50min under the condition of 0.5MPa and 240 ℃ in a carbon dioxide atmosphere, then releasing pressure to normal pressure within 37min, and stopping the reaction when the water yield reaches 98.6% of the theoretical water yield to obtain a prepolymer with the polymerization degree of 17;
Wherein, the mol ratio of diamine A to dicarboxylic acid A is 1:1; the addition amount of the carrier substance is 35% of the total mass of diamine A and dicarboxylic acid A; the addition amount of trace substances is 0.2wt percent, the addition amount of the catalyst is 0.001wt percent and the addition amount of the thermal oxygen stabilizer is 0.02wt percent based on the total mass of diamine A, dicarboxylic acid A and carrier substances;
(4) And (3) reacting the prepolymer obtained in the step (3) for 20min under the conditions of-0.06 MPa and 260 ℃ to obtain the polyamide.
The final polyamide had a relative viscosity of 2.5, a yellowness index of-4, a molecular weight distribution range of 1.8 and a gel particle content of 0.01 wt.%.
Comparative example 3
A polyamide synthesis process substantially as hereinbefore described with reference to example 6, except that: in the step (3), the addition amount of the carrier substance is 60% of the total mass of diamine A and dicarboxylic acid A.
The molecular weight distribution of the finally produced polyamide was 3.1.
Comparative example 3 is greatly widened in the molecular weight distribution range compared with example 6 because the addition amount of the carrier substance is excessively large, the viscosity of the system is large in the early stage of the initial reaction, the diffusivity of the diamine a and the dicarboxylic acid a in the system is poor, the degree of dispersion of the degree of polymerization is large, and the molecular weight distribution range of the final sample is greatly widened.

Claims (8)

1. A short-process polyamide synthesis method is characterized in that: diamine A, dicarboxylic acid A and carrier materials are used as main raw materials, and the pre-polymerization and polycondensation reactions are directly carried out to prepare polyamide;
the carrier material is oligomer generated by the reaction of diamine B and dicarboxylic acid B;
The molar ratio of diamine A to dicarboxylic acid A is 1:1;
The addition amount of the carrier substance is 0.5-49.9% of the total mass of diamine A and dicarboxylic acid A.
2. The method for synthesizing a short-run polyamide according to claim 1, wherein the number average molecular weight of the carrier substance is 3000 to 5000.
3. The method for synthesizing a short-process polyamide according to claim 1, wherein diamine A and diamine B are independently selected from one or more of butanediamine, pentanediamine, hexanediamine, heptanediamine, octanediamine, nonanediamine, decanediamine, and long-chain diamine having eleven to eighteen carbon atoms, and dicarboxylic acid A and dicarboxylic acid B are independently selected from one or more of terephthalic acid, isophthalic acid, succinic acid, glutaric acid, adipic acid, heptanedioic acid, octanedioic acid, azelaic acid, sebacic acid, and long-chain dicarboxylic acid having eleven to eighteen carbon atoms.
4. The method for synthesizing short-process polyamide according to claim 1, comprising the following specific steps:
(1) Pre-polymerization reaction;
Adding diamine A and dicarboxylic acid A into a reaction system consisting of a carrier substance, a trace substance, a catalyst and a thermal oxygen stabilizer in steps, reacting for 30-50 min under the condition of 0.5-1.5 MPa and 180-260 ℃ in a nitrogen or carbon dioxide atmosphere, then releasing pressure to normal pressure within 10-40 min, and stopping the reaction when the water yield reaches more than 98.5% of the theoretical water yield to obtain a prepolymer;
The trace substances are one or more of caprolactam, enantholactam, caprylic lactam, pelargonamide, capric lactam, lactam with eleven to fifteen carbon atoms, aminocaproic acid, aminoheptanoic acid, aminocaprylic acid, aminononanoic acid, aminodecanoic acid and amino acid with eleven to fifteen carbon atoms;
The addition amount of trace substances is not more than 0.5wt% based on the total mass of diamine A, dicarboxylic acid A and carrier substances;
(2) Performing polycondensation reaction;
and (3) reacting the prepolymer obtained in the step (1) for 10-30 min under the conditions of minus 0.100 to minus 0.030MPa and 200-280 ℃ to obtain the polyamide.
5. The method for synthesizing a short-run polyamide as claimed in claim 4, wherein the polymerization degree of the prepolymer obtained in the step (1) is 10 to 25.
6. The method for synthesizing polyamide in short process according to claim 4, wherein the catalyst in the step (1) is one or more of potassium phosphite, sodium phosphite, magnesium phosphite, aluminum phosphite, calcium phosphite, barium phosphite, zinc phosphite, potassium hypophosphite, sodium hypophosphite, magnesium hypophosphite, calcium hypophosphite, zinc hypophosphite, aluminum hypophosphite and barium hypophosphite, and the thermo-oxidative stabilizer is one or more of antioxidant 1010, antioxidant 1096, antioxidant 168, triphenyl phosphite and triphenyl phosphate.
7. The method for synthesizing a short-process polyamide according to claim 6, wherein the addition amount of the trace substances is 0.1 to 0.5wt%, the addition amount of the catalyst is 0.001 to 0.05wt%, and the addition amount of the thermal oxygen stabilizer is 0.001 to 0.05wt%, based on the total mass of the diamine a, the dicarboxylic acid a and the carrier substance.
8. The method for synthesizing short-process polyamide according to claim 4, wherein the polyamide obtained in the step (2) has a relative viscosity of 2.2-2.9, a yellowness index of less than or equal to-1, a molecular weight distribution range of 1.2-2, and a gel particle content of not more than 0.1wt%.
CN202410529700.3A 2024-04-29 2024-04-29 Short-process polyamide synthesis method Pending CN118085272A (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101180342A (en) * 2005-05-20 2008-05-14 Ems-化学公开股份有限公司 Polyamide oligomer as well as purpose thereof
WO2017080494A1 (en) * 2015-11-13 2017-05-18 昆山天洋热熔胶有限公司 High-performance polyamide hot melt adhesive for surface decoration and preparation method therefor
KR101938615B1 (en) * 2017-08-24 2019-01-15 롯데케미칼 주식회사 Method for preparing polyamide resin
CN114058009A (en) * 2021-12-13 2022-02-18 山东广垠新材料有限公司 Process for preparing semi-aromatic polyamides with reduced loss of diamine monomer, semi-aromatic polyamides and molding compositions
US20230016115A1 (en) * 2020-03-28 2023-01-19 Chengdu 401 Technology Co., Ltd. Continuous polymerization method for nylon

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101180342A (en) * 2005-05-20 2008-05-14 Ems-化学公开股份有限公司 Polyamide oligomer as well as purpose thereof
WO2017080494A1 (en) * 2015-11-13 2017-05-18 昆山天洋热熔胶有限公司 High-performance polyamide hot melt adhesive for surface decoration and preparation method therefor
KR101938615B1 (en) * 2017-08-24 2019-01-15 롯데케미칼 주식회사 Method for preparing polyamide resin
US20230016115A1 (en) * 2020-03-28 2023-01-19 Chengdu 401 Technology Co., Ltd. Continuous polymerization method for nylon
CN114058009A (en) * 2021-12-13 2022-02-18 山东广垠新材料有限公司 Process for preparing semi-aromatic polyamides with reduced loss of diamine monomer, semi-aromatic polyamides and molding compositions

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