阅读说明：本技术 一种半芳香族聚酰胺树脂及其制备方法 (Semi-aromatic polyamide resin and preparation method thereof ) 是由 杨剑停 汤锡銮 康杰 严海南 高向东 于 2020-12-04 设计创作，主要内容包括：本发明公开了一种半芳香族聚酰胺树脂及其制备方法。本发明通过在二元酸和二元胺和/或内酰胺缩聚的过程中,加入有机溶剂改善半芳香族酰胺盐及低聚物在体系中的溶解度,减小了半芳香族酰胺盐及低聚物发生析出结块的风险,保证了反应体系均一性、体系配比平衡和体系粘度可控性,从而有利于半芳香族聚酰胺产品的顺利生产和产品品质,降低了生产成本和生产风险,增加了市场竞争力。(The invention discloses a semi-aromatic polyamide resin and a preparation method thereof. According to the invention, in the process of polycondensation of the dibasic acid and the diamine and/or the lactam, the organic solvent is added to improve the solubility of the semi-aromatic amide salt and the oligomer in the system, reduce the risk of precipitation and agglomeration of the semi-aromatic amide salt and the oligomer, and ensure the uniformity of the reaction system, the balance of the system proportion and the controllability of the system viscosity, thereby being beneficial to smooth production and product quality of the semi-aromatic polyamide product, reducing the production cost and the production risk, and increasing the market competitiveness.)

1. A semi-aromatic polyamide resin characterized by comprising: the semi-aromatic polyamide resin comprises the following raw materials in parts by weight: 20-70 parts of dibasic acid, 20-50 parts of diamine, 0-30 parts of amino acid or lactam, 0.05-1 part of end capping agent, 0.01-0.5 part of catalyst, 30-160 parts of water and 5-50 parts of organic solvent with the amide salt solubility being more than 0.001 g.

2. The semi-aromatic polyamide resin according to claim 1, characterized in that: 30-65 parts of dibasic acid; 20-45 parts of diamine; 0-20 parts of amino acid or lactam; 0.1-0.5 part of end-capping agent; 0.02-0.2 part of catalyst; 40-150 parts of water; and 5-25 parts of an organic solvent.

3. The semi-aromatic polyamide resin according to claim 1, characterized in that: the boiling point of the organic solvent is not lower than 100 ℃.

4. The semi-aromatic polyamide resin according to claim 1, characterized in that: the boiling point of the organic solvent is 100-320 ℃.

5. The semi-aromatic polyamide resin according to claim 1, characterized in that: the organic solvent includes at least one of 1, 4-dioxane, toluene, nitroethane, pyridine, 4-methyl-2-pentanone, octane, morpholine, chlorobenzene, p-xylene, m-xylene, o-xylene, N-dimethylformamide, cyclohexanone, N-dimethylacetamide, furfural, N-methylformamide, dimethyl sulfoxide, N-methylpyrrolidone, formamide, nitrobenzene, acetamide, hexamethylphosphoric triamide, quinoline, succinonitrile, or sulfolane.

6. The semi-aromatic polyamide resin according to claim 1, characterized in that: the dibasic acid comprises at least one of aromatic dibasic acid, aliphatic dibasic acid or alicyclic dibasic acid; the diamine comprises at least one of aliphatic diamine, aromatic diamine or alicyclic diamine.

7. The semi-aromatic polyamide resin according to claim 1, characterized in that: the amino acid comprises at least one of 4-aminobutyric acid, 6-aminocaproic acid, 7-aminoheptanoic acid, 8-aminocaprylic acid, 9-aminononanoic acid, 10-aminodecanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, 4-aminocyclohexanecarboxylic acid, 4- (aminomethyl) -cyclohexanecarboxylic acid, p-aminobenzoic acid, or hydroxytryptophan; the lactam comprises at least one of beta-propiolactam, gamma-butyrolactam, delta-valerolactam, epsilon-caprolactam, enantholactam, caprylolactam, nonalactam, caprylolactam, undecanolactam, or laurolactam.

8. The semi-aromatic polyamide resin according to claim 1, characterized in that: the blocking agent comprises at least one of monocarboxylic acid, monoamine, anhydride, monoisocyanate, monoacid chloride, monoester or monoalcohol; the catalyst comprises at least one of phosphoric acid, phosphorous acid, hypophosphorous acid or metal salts or esters thereof.

9. The semi-aromatic polyamide resin according to claim 1, characterized in that: 30-35 parts of dibasic acid; 20-35 parts of diamine; 0.1-0.25 part of end-capping agent; 0.03-0.05 part of catalyst; 40-45 parts of water; 6-14 parts of an organic solvent; the dibasic acid is at least one of terephthalic acid, isophthalic acid or adipic acid; the diamine is at least one of hexamethylene diamine, nonane diamine or decamethylene diamine; the end-capping reagent is at least one of acetic acid or benzoic acid; the organic solvent is at least one of N, N-dimethylformamide, N-methylpyrrolidone or toluene.

10. A method for preparing a semi-aromatic polyamide resin according to any one of claims 1 to 9, characterized in that: putting the raw materials into protective gas under a micro-positive pressure condition, stirring and heating to 60-150 ℃, reacting at a constant temperature for 1-3 h, then continuously heating to 200-240 ℃, keeping the pressure at 1.5-3.0 MPa, and keeping the temperature for 1-5 h; continuously heating and maintaining a constant pressure state; after the temperature is increased to 240-340 ℃, the pressure is released to 0MPa after 0.5-2 h, and then the reaction is carried out for 0.1-1 h at constant temperature and normal pressure, thus obtaining the product.

Technical Field

The invention belongs to the technical field of synthesis of high polymer materials, and particularly relates to semi-aromatic polyamide resin.

Background

Polyamides, commonly known as nylons, the english name Polyamide, are a general name for thermoplastic resins containing a recurring amide group — [ NHCO ] -, in the molecular main chain, and include aliphatic polyamides, semi-aromatic polyamides and wholly aromatic polyamides. The semi-aromatic polyamide maintains the processability of aliphatic polyamide while providing rigidity and heat resistance of the wholly aromatic polyamide, has low water absorption rate, good dimensional stability and high strength and modulus, and is widely applied to the fields of automobile internal combustion engine parts, heat-resistant electric appliance parts, transmission parts, Surface Mount Technology (SMT) and the like.

Similar to aliphatic polyamide products, semi-aromatic polyamide products are also obtained by condensation polymerization of dibasic acid and diamine and/or lactam, but because the semi-aromatic polyamide products contain aromatic dibasic acid or aromatic diamine, the formed amide salt has high melting point and low solubility in aqueous solution, and in the process of discharging water vapor by condensation polymerization and pressure maintaining, the amide salt or oligomer often precipitates and agglomerates, so that a reaction kettle cannot be stirred, the uniformity of a reaction system is poor, the system proportion is unbalanced, the viscosity cannot be controlled, bubbles and even implosion phenomena occur, the yield is reduced, even production equipment is directly damaged and scrapped, and the smooth production of the semi-aromatic polyamide products and the uniformity of the product quality are greatly disturbed.

The most direct solution is to improve the pressure grade of the production equipment, so that the reaction system maintains pressure and discharges water vapor under higher pressure, and ensures that the system has enough water content to dissolve aromatic amide salt and oligomer. And the safety risk in the production process can be greatly improved and the severity of damage after production accidents is increased by increasing the reaction pressure level.

In addition, the risk of agglomeration of the aromatic amide salt in the pressure maintaining and exhausting process can be reduced by reducing the adding amount of the aromatic unit in the semi-aromatic polyamide product, but the reduction of the aromatic unit can also reduce the mechanical properties such as temperature resistance, modulus and the like of the final product, and cannot meet the use requirements of customers.

In addition, many documents often adopt a method of polymerizing at a relatively low temperature and pressure to obtain an oligomer with a relatively low molecular weight, and then continuing the polymerization by post-polymerization or solid-phase polycondensation to obtain a semi-aromatic polyamide product with a desired molecular weight. The method can effectively solve the problems of high pressure grade of polymerization equipment and poor product uniformity, and simultaneously ensures the aromatic unit content, temperature resistance, modulus and other properties of the product. However, the method increases the number of equipment, prolongs the reaction process, increases the reaction procedures and the production cost, and is not favorable for the market competitiveness of the product. And the product after solid phase polycondensation is powder and can be converted into marketable slices through melt granulation, so that the production procedures and cost are continuously increased, and the product quality is reduced to a certain extent through the increased melt granulation process.

Therefore, there is a need for further optimization of the semi-aromatic polyamide product and the process for producing the same.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a semi-aromatic polyamide resin and a preparation method thereof.

One of the purposes of the invention is to prepare a novel semi-aromatic polyamide resin, and the invention improves the solubility of semi-aromatic amide salt and oligomer in a system by adding an organic solvent in the process of polycondensation of dibasic acid and diamine and/or lactam, reduces the risk of precipitation and agglomeration of the semi-aromatic amide salt and oligomer, and ensures the uniformity of a reaction system, the balance of the system proportion and the controllability of the system viscosity, thereby being beneficial to the smooth production of semi-aromatic polyamide products and the uniformity of the product quality. Meanwhile, the pressure grade of polymerization equipment is reduced, and equipment investment and production safety risks are reduced. The one-step polycondensation reaction shortens the production flow and working procedures, reduces the production cost, increases the market competitiveness, and the obtained product is a slice which can be directly sold, thereby avoiding the influence of secondary granulation on the product quality. The added organic solvent is discharged for recycling in the later pressure relief process, and adverse effects on the product quality and the environment are avoided.

Another object of the present invention is to provide a method for preparing such a semi-aromatic polyamide resin.

In order to achieve the purpose, one of the technical schemes adopted by the invention is as follows:

the semi-aromatic polyamide resin comprises the following raw materials in parts by weight: 20-70 parts of dibasic acid, 20-50 parts of diamine, 0-30 parts of amino acid or lactam, 0.05-1 part of end capping agent, 0.01-0.5 part of catalyst, 30-160 parts of water and 5-50 parts of organic solvent with the amide salt solubility being more than 0.001 g.

Preferably, the dibasic acid accounts for 30-65 parts;

preferably, 20-45 parts of diamine;

preferably, the amino acid or the lactam accounts for 0-20 parts;

preferably, the end-capping agent is 0.1-0.5 part;

preferably, the catalyst is 0.02-0.2 part;

preferably, the water accounts for 40-150 parts;

preferably, the organic solvent is 5-25 parts.

Wherein the dibasic acid is selected from one or a mixture of more of aromatic dibasic acid, aliphatic dibasic acid and alicyclic dibasic acid.

The aromatic dibasic acid is selected from one or a mixture of more of terephthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid, 5-hydroxyisophthalic acid, phthalic acid, 2-methyl terephthalic acid, 5-tert-butyl isophthalic acid and naphthalenedicarboxylic acid, and further preferably one or a mixture of two of terephthalic acid and isophthalic acid.

The aliphatic dibasic acid is selected from aliphatic C2-C36 dibasic acids with straight chains or branched chains, preferably one or a mixture of more of oxalic acid, malonic acid, dimethylmalonic acid, succinic acid, 3-diethylsuccinic acid, glutaric acid, 2-dimethylglutaric acid, adipic acid, 2-methyladipic acid, 2,4, 4-trimethyladipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid, octadecenedioic acid, didecanedioic acid and docosanedioic acid, and further preferably one or a mixture of more of succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, undecanedioic acid and dodecanedioic acid.

The alicyclic diacid is selected from diacid of C6-C36 with alicyclic ring, preferably 1, 3-cyclopentanedicarboxylic acid, 1, 2-cyclohexanedicarboxylic acid, 4-methyl-1, 2-cyclohexanedicarboxylic acid, cis/trans-1, 3-cyclohexanedicarboxylic acid, cis/trans-1, 4-cyclohexanedicarboxylic acid, cycloheptanedicarboxylic acid, cyclooctanedicarboxylic acid, cyclodecanedioic acid, 1, 3-cyclohexanediacetic acid and 1, 4-cyclohexanediacetic acid, and more preferably cis/trans-1, 4-cyclohexanedicarboxylic acid.

The diamine is selected from one or a mixture of several of aliphatic diamine, aromatic diamine and alicyclic diamine. The diamine and the diacid in the reaction system are basically equimolar, and the viscosity of the product is reduced and the mechanical property is poor due to too much or too little addition amount, so that the method has no practical value.

The aliphatic diamine is selected from ethylenediamine, 1-butyl-ethylenediamine, propylenediamine, 1, 2-propylenediamine, butylenediamine, 1, 3-butylenediamine, 1-dimethylbutylenediamine, 1, 2-dimethylbutylenediamine, 1, 3-dimethylbutylenediamine, 1, 4-dimethylbutylenediamine, 2, 3-dimethylbutylenediamine, 1-ethylbutylenediamine, 2-ethylbutylenediamine, pentylenediamine, 1, 3-pentylenediamine, 2-methyl-1, 5-pentylenediamine, 3-methyl-1, 5-pentylenediamine, 2-dimethylpentyldiamine, 2-butyl-2-ethyl-1, 5-pentylenediamine, hexylenediamine, 2-methylhexyldiamine, 3-methylhexyldiamine, hexamethylenediamine, tetramethylethylenediamine, tetramethyl, 1-butylhexamethylenediamine, 2-dimethylhexamethylenediamine, 2, 4-dimethylhexamethylenediamine, 2, 5-dimethylhexamethylenediamine, 3-dimethylhexamethylenediamine, 2, 4-diethylhexamethylenediamine, 2, 4-trimethylhexamethylenediamine, 2,4, 4-trimethylhexamethylenediamine, heptanediamine, 2-dimethylheptanediamine, 2, 3-dimethylheptanediamine, 2, 4-dimethylheptanediamine, 2, 5-dimethylheptanediamine, octanediamine, 2-methyl-1, 8-octanediamine, 3-methyl-1, 8-octanediamine, 4-methyl-1, 8-octanediamine, 1, 3-dimethyloctanediamine, 1, 4-dimethyloctanediamine, 2-dimethyloctanediamine, 2, 4-dimethyl octanediamine, 3-dimethyl octanediamine, 3, 4-dimethyl octanediamine, 4, 5-dimethyl octanediamine, 2,7, 7-tetramethyl octanediamine, nonane diamine, 5-methyl nonane diamine, decane diamine, undecane diamine, dodecane diamine, tridecane diamine, tetradecane diamine, pentadecane diamine, hexadecane diamine, heptadecane diamine, octadecane diamine, octadecene diamine, nonadecane diamine, eicosane diamine, docosane diamine, polyether (PEG, PPG, PTMG) diamine, further preferably one or more mixtures of butanediamine, pentanediamine, 2-methyl pentanediamine, hexanediamine, octanediamine, nonane diamine, decane diamine, dodecane diamine.

The amino acid is selected from one or a mixture of more of 4-aminobutyric acid, 6-aminocaproic acid, 7-aminoheptanoic acid, 8-aminocaprylic acid, 9-aminononanoic acid, 10-aminodecanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, 4-aminocyclohexanecarboxylic acid, 4- (aminomethyl) -cyclohexanecarboxylic acid, p-aminobenzoic acid and hydroxytryptophan, and preferably one or a mixture of more of 6-aminocaproic acid, 11-aminoundecanoic acid and 12-aminododecanoic acid.

The lactam is selected from one or a mixture of more of beta-propiolactam, gamma-butyrolactam, delta-valerolactam, epsilon-caprolactam, enantholactam, caprylolactam, nonanolactam, decanolactam, undecanolactam and laurolactam, and preferably from one or a mixture of more of epsilon-caprolactam, undecanolactam and laurolactam. The amino acid and the lactam can be added to the reaction system in any proportion.

The end-capping reagent is selected from monofunctional compounds capable of reacting with amino or carboxyl at the tail end of a polyamide molecular chain, and can be monocarboxylic acid, monoamine, anhydride, monoisocyanate, monoacid chloride, monoester, monoalcohol and the like, and preferably one or a mixture of more of acetic acid, caproic acid, benzoic acid, ethylamine, hexylamine and aniline. The end-capping agent is used for adjusting the molecular weight of the product, particularly, the amino group at the tail end of a polyamide molecular chain can be capped by the monoacid component, the molecular weight distribution is narrowed during polymerization, the deterioration of the catalyst is reduced, gas is reduced during molding, the demolding performance is improved, and the performance deterioration and the color change caused by thermal degradation and oxidative degradation in the heating state during processing and using processes are prevented; the viscosity of the product is reduced, the molecular weight is reduced and the mechanical property is deteriorated due to the over-high content of the end capping agent; when the content is too low, the content of the terminal functional group becomes too high, which causes gelation or deterioration at the time of melt retention, and causes problems such as coloration or hydrolysis in the use environment.

The catalyst is selected from phosphoric acid, phosphorous acid, hypophosphorous acid or metal salts or esters thereof, the metal salts are preferably potassium, sodium, magnesium, vanadium, calcium, zinc, cobalt, manganese, tin, tungsten, germanium, titanium, antimony, nickel and the like, and the esters are preferably methyl ester, ethyl ester, isopropyl ester, butyl ester, hexyl ester, decyl ester, isodecyl ester, octadecyl ester, phenyl ester and the like. The catalyst has a catalytic effect in a system, so that the reaction rate is accelerated, and the branched content in the main chain is reduced, thereby being beneficial to reducing the PDI of the polyamide product; preferably 0.02-0.05 part, too little dosage, no catalytic effect, too much dosage, too large polymerization degree and difficult processing.

The organic solvent is selected from organic solvents with the solubility of amide salt being more than 0.001g, preferably the organic solvent with the boiling point being more than 100 ℃ and the solubility of amide salt being more than 0.001g, more preferably the organic solvent with the boiling point being more than 100 ℃ and the solubility of amide salt being more than 320 ℃ is more than 0.001g, more preferably the organic solvent is selected from 1, 4-dioxane, toluene, nitroethane, pyridine, 4-methyl-2-pentanone, octane, morpholine, chlorobenzene, p-xylene, m-xylene, o-xylene, N-dimethylformamide, cyclohexanone, N-dimethylacetamide, furfural, N-methylformamide, dimethyl sulfoxide, N-methylpyrrolidone, formamide, nitrobenzene, acetamide, hexamethylphosphoric triamide, quinoline, succinonitrile and sulfolane, and most preferably the mixture of one or more than one of 1, 4-dioxane, ethanol, one or a mixture of more of toluene, pyridine, octane, p-xylene, N-dimethylformamide, N-dimethylacetamide, dimethyl sulfoxide and N-methylpyrrolidone. The solubility of the amide salt is too low, and the dissolution of the amide salt is not promoted in the system, and the precipitation and agglomeration of the amide salt are prevented. The boiling point is too low, the water is discharged before the pressure-holding process, the effect of increasing the amide salt solubility cannot be achieved at the later stage of pressure holding, the boiling point is too high, the water cannot be discharged from the reaction system at the tail end of exhaust, and the water remains in the reaction product to influence the performance of the final product. The organic solvent is preferably 5-25 parts, the addition amount is too small, the dissolving effect on the amide salt and the oligomer is not good, the precipitation and agglomeration of the amide salt and the oligomer are not favorably prevented, time and energy are consumed for discharging at the later stage when the addition amount is too large, the production efficiency is reduced, and the production cost is increased.

In a preferred embodiment, the dibasic acid is 30-35 parts; 20-35 parts of diamine; 0.1-0.25 part of end-capping agent; 0.03-0.05 part of catalyst; 40-45 parts of water; 6-14 parts of an organic solvent; the dibasic acid is at least one of terephthalic acid, isophthalic acid or adipic acid; the diamine is at least one of hexamethylene diamine, nonane diamine or decamethylene diamine; the end-capping reagent is at least one of acetic acid or benzoic acid; the organic solvent is at least one of N, N-dimethylformamide, N-methylpyrrolidone or toluene.

In order to achieve the purpose, the second technical scheme adopted by the invention is as follows:

the preparation method of the semi-aromatic polyamide resin comprises the steps of putting the raw materials into protective gas under a micro-positive pressure condition, stirring, heating to 60-150 ℃, reacting at a constant temperature for 1-3 hours, then continuously heating to 200-240 ℃, keeping the pressure to 1.5-3.0 MPa, and keeping the temperature for 1-5 hours; continuously heating and maintaining a constant pressure state; after the temperature is increased to 240-340 ℃, the pressure is released to 0MPa after 0.5-2 h, and then the reaction is carried out for 0.1-1 h at constant temperature and normal pressure, thus obtaining the product.

Wherein the micro positive pressure is not higher than 0.06MPa, for example, 0-0.05 MPa. The protective gas is, for example, nitrogen.

Specifically, the preparation method comprises the following steps:

(1) weighing 20-70 parts by weight of dibasic acid, 20-50 parts by weight of diamine, 0-30 parts by weight of amino acid/lactam, 0.05-1 part by weight of end capping agent, 0.01-0.5 part by weight of catalyst, 30-160 parts by weight of deionized water and 10-50 parts by weight of organic solvent, adding the mixture into a high-pressure reaction kettle, vacuumizing and filling nitrogen into the high-pressure reaction kettle, repeating the steps for three times to remove residual air in the reaction kettle, and keeping the micro-positive pressure of the high-pressure reaction kettle at 0.05MPa after the replacement is finished;

(2) heating the high-pressure reaction kettle to 60-150 ℃ under the stirring condition of 100r/min, reacting at a constant temperature for 1-3 h, then continuously heating to 200-240 ℃, keeping the pressure at 1.5-3.0 MPa, and keeping the temperature for 1-5 h;

(3) continuously heating, simultaneously enabling the high-pressure reaction kettle to be in a constant-pressure state by a method of releasing water vapor and an organic solvent in the high-pressure reaction kettle, slowly releasing the pressure in the kettle to 0MPa after 0.5-2 h when the temperature is increased to 240-340 ℃, and then carrying out constant-temperature reaction for 0.1-1 h at normal pressure;

(4) and extruding the polymer from the high-pressure reaction kettle through a die head, cooling the polymer by a water tank and granulating the polymer to obtain a novel polyamide product.

The equipment, reagents, processes, parameters and the like related to the invention are conventional equipment, reagents, processes, parameters and the like except for special description, and no embodiment is needed.

All ranges recited herein include all point values within the range.

Compared with the prior art, the invention has the following advantages:

1. according to the invention, the organic solvent is added in the polymerization process of the semi-aromatic polyamide resin, so that the solubility of the amide salt and the oligomer is increased, the temperature and pressure required for completely dissolving the amide salt and the oligomer in water are reduced, the pressure requirement on equipment is reduced, the equipment investment and the production cost are saved, and the market competitiveness of the product is enhanced.

2. By adding the organic solvent, the invention reduces the pressure grade of polymerization equipment, and reduces the safety risk in the production process and the severity of damage after production accidents.

3. According to the invention, the organic solvent is added, so that the solubility of the amide salt and the oligomer is promoted, the problems of amide salt precipitation, solid-phase separation of a reaction system and deterioration of uniformity in the process of water vapor discharge are prevented, and the smooth production of the semi-aromatic polyamide product and the uniformity of the product quality are facilitated.

4. The method synthesizes the semi-aromatic polyamide product by a one-step method, reduces the number of equipment and reaction procedures, improves the production efficiency, reduces the production cost and is beneficial to increasing the market competitiveness of the product.

5. The semi-aromatic polyamide product is synthesized by a one-step method, the obtained product is a slice which can be directly sold, and the influence on the product quality caused by secondary granulation required by adopting a solid phase polycondensation process is avoided.

6. The added organic solvent can be discharged along with the water vapor in the later high-temperature pressure relief process, and cannot remain in a product system to influence the product quality.

7. The organic solvent added in the invention is discharged in the later high-temperature pressure relief process, and then is condensed and enters the next reaction process again for recycling, thus having no influence on the environment.

8. The invention has essential difference from the conventional solution polymerization which totally uses organic solvent by adding a small amount of organic solvent, and the essence still belongs to melt polycondensation. Meanwhile, the use amount of the organic solvent is reduced, the workload of recovering the organic solvent is also reduced, and the production cost is reduced.

Detailed Description

The present invention will be described in detail with reference to the following examples:

in the examples provided below, the following detection methods were employed:

melting Point T_mAnd glass transition temperature T_g: according to ISO 11357: heating to 350 deg.C at 20 deg.C/min with differential scanning calorimeter (DSC 3 of Mettler-Tollido Co.), standing for 2min, cooling to 25 deg.C at 20 deg.C/min, standing for 2min, heating to 350 deg.C at 20 deg.C/min, and determining the temperature corresponding to the heat absorption peak of the second heating curve as melting point T_mThe midpoint of the glass transition measured by the half-step height method is the glass transition temperature T_g。

Example 1

(1)1661g (10mol) of terephthalic acid, 1723g (10mol) of decamethylene diamine, 12g (0.1mol) of end-capping reagent benzoic acid, 2g of catalyst sodium hypophosphite, 2000g of deionized water and 400g of N, N-dimethylformamide are weighed and added into a high-pressure reaction kettle, the high-pressure reaction kettle is vacuumized and filled with nitrogen, the residual air in the reaction kettle is removed by repeating the steps for three times, and the micro-positive pressure of the high-pressure reaction kettle is kept at 0.05MPa after the replacement is finished;

(2) heating the high-pressure reaction kettle to 130 ℃ under the stirring condition of 100r/min, reacting for 2 hours at constant temperature, then continuously heating to 220 ℃, keeping the pressure at 2.0MPa, and keeping the temperature for 2 hours;

(3) continuously heating, simultaneously enabling the high-pressure reaction kettle to be in a constant pressure state of 2.0MPa by a method of releasing steam and N, N-dimethylformamide in the high-pressure reaction kettle, slowly releasing the pressure in the kettle to 0MPa after 1h when the temperature is raised to 320 ℃, and then carrying out constant-temperature reaction for 0.3h at normal pressure;

(4) and extruding the polymer from a high-pressure reaction kettle through a die head, cooling the polymer by a water tank, and pelletizing to obtain the poly (decamethylene terephthalamide) resin. The starting monomers and their properties of example 1 are listed in table 1.

Example 2

(1) Weighing 1163g (7mol) of terephthalic acid, 498g (3mol) of isophthalic acid, 1162g (10mol) of hexamethylene diamine, 12g (0.1mol) of end-capping reagent benzoic acid, 2g of catalyst sodium hypophosphite, 2000g of deionized water and 400g of N-methylpyrrolidone, adding the materials into a high-pressure reaction kettle, vacuumizing and filling nitrogen into the high-pressure reaction kettle, repeating the steps for three times to remove residual air in the reaction kettle, and keeping the micro-positive pressure of the high-pressure reaction kettle to be 0.05MPa after replacement is finished;

(2) heating the high-pressure reaction kettle to 100 ℃ under the stirring condition of 100r/min, reacting at constant temperature for 1.5h, then continuously heating to 228 ℃, keeping the pressure at 2.5MPa, and keeping the temperature for 2.5 h;

(3) continuously heating, simultaneously enabling the high-pressure reaction kettle to be in a constant pressure state of 2.5MPa by a method of releasing steam and N-methyl pyrrolidone in the high-pressure reaction kettle, slowly releasing the pressure in the kettle to 0MPa after 0.8h when the temperature is raised to 330 ℃, and then carrying out constant-temperature reaction for 0.2h at normal pressure;

(4) and extruding the polymer from a high-pressure reaction kettle through a die head, cooling the polymer by a water tank and granulating the polymer to obtain the poly (hexamethylene terephthalamide) -co-isophthalamide copolymer resin. The starting monomers and their properties of example 2 are listed in table 1.

Example 3

(1) 914g (5.5mol) of terephthalic acid, 658g (4.5mol) of adipic acid, 1162g (10mol) of hexamethylenediamine, 12g (0.1mol) of end-capping reagent benzoic acid, 2g of catalyst sodium hypophosphite, 2000g of deionized water and 500g of N, N-dimethylformamide are weighed and added into a high-pressure reaction kettle, the high-pressure reaction kettle is vacuumized and filled with nitrogen, the three times of steps are carried out to remove residual air in the reaction kettle, and the micro positive pressure of the high-pressure reaction kettle is kept at 0.05MPa after the replacement is finished;

(2) heating the high-pressure reaction kettle to 80 ℃ under the stirring condition of 100r/min, reacting at constant temperature for 2.5h, then continuously heating to 205 ℃, keeping the pressure at 1.8MPa, and keeping the temperature for 1.5 h;

(3) continuously heating, simultaneously enabling the high-pressure reaction kettle to be in a constant pressure state of 1.8MPa by a method of releasing steam and N, N-dimethylformamide in the high-pressure reaction kettle, slowly releasing the pressure in the kettle to 0MPa after 1.5h when the temperature is increased to 315 ℃, and then carrying out constant-temperature reaction for 0.8h at normal pressure;

(4) and extruding the polymer from a high-pressure reaction kettle through a die head, cooling the polymer by a water tank and pelletizing the polymer to obtain the poly (hexamethylene terephthalamide) -co-hexamethylene adipamide copolymer resin. The starting monomers and their properties of example 3 are listed in table 1.

Example 4

(1)1661g (10mol) of terephthalic acid, 1583g (10mol) of nonane diamine, 6g (0.1mol) of end-capping reagent acetic acid, 2g of catalyst sodium hypophosphite, 2000g of deionized water and 600g of toluene are added into a high-pressure reaction kettle, the high-pressure reaction kettle is vacuumized and filled with nitrogen, the vacuum and nitrogen are repeatedly pumped for three times to remove residual air in the reaction kettle, and the micro-positive pressure of the high-pressure reaction kettle is kept at 0.05MPa after the replacement is finished;

(2) heating the high-pressure reaction kettle to 140 ℃ under the stirring condition of 100r/min, reacting for 1h at constant temperature, then continuously heating to 223 ℃, keeping the pressure at 2.2MPa, and keeping the temperature for 3 h;

(3) continuously heating, simultaneously enabling the high-pressure reaction kettle to be in a constant pressure state of 2.2MPa by a method of releasing steam and methylbenzene in the high-pressure reaction kettle, slowly releasing the pressure in the kettle to 0MPa after 0.6h when the temperature is raised to 312 ℃, and then carrying out constant-temperature reaction for 1h at normal pressure;

(4) and extruding the polymer from a high-pressure reaction kettle through a die head, cooling the polymer by a water tank, and pelletizing to obtain the poly (nonane terephthalamide) resin. The starting monomers and their properties of example 4 are listed in table 1.

Comparative example 1

1661g (10mol) of terephthalic acid, 1723g (10mol) of decamethylene diamine, 12g (0.1mol) of an end-capping reagent benzoic acid, 2g of a catalyst sodium hypophosphite, and 2000g of deionized water were weighed and charged into a high-pressure reactor, and in the same manner as in example 1, 10T salt and oligomer began to precipitate when the temperature rise stage (265 ℃) was carried out under a pressure-maintaining (2.0MPa), which hindered the stirring of the reactor and stopped the reaction. The raw material monomers of comparative example 1 and the comparative results are shown in table 2.

Comparative example 2

Poly (decamethylene terephthalamide) resin was synthesized in the same manner as in example 1 except that 1661g (10mol) of terephthalic acid, 1723g (10mol) of decamethylene diamine, 12g (0.1mol) of end-capping reagent benzoic acid, 2g of catalyst sodium hypophosphite, and 2000g of deionized water were weighed and charged in a high-pressure reactor, and the temperature was raised to 235 ℃ to start holding pressure (2.8MPa), and the raw material monomers and properties of comparative example 2 are shown in Table 2.

Comparative example 3

1163g (7mol) of terephthalic acid, 498g (3mol) of isophthalic acid, 1162g (10mol) of hexamethylenediamine, 12g (0.1mol) of benzoic acid as a blocking agent, 2g of sodium hypophosphite as a catalyst, and 2000g of deionized water were weighed and charged into a high-pressure reactor, and in the same manner as in example 2, when the temperature rise stage (261 ℃) was reached under a pressure-maintaining condition (2.5MPa), 6T salt and oligomer began to precipitate, which prevented the reactor from stirring and stopped the reaction. The raw material monomers of comparative example 3 and the comparative results are shown in table 2.

Comparative example 4

A polyhexamethylene terephthalamide-co-isophthalamide copolymer resin was synthesized in the same manner as in example 2 except that 1163g (7mol) of terephthalic acid, 498g (3mol) of isophthalic acid, 1162g (10mol) of hexamethylenediamine, 12g (0.1mol) of the blocking agent benzoic acid, 2g of the catalyst sodium hypophosphite and 2000g of deionized water were weighed and charged in a high-pressure reactor, and the temperature was raised to 240 ℃ to start holding the pressure (3.5MPa), and the raw material monomers and properties of comparative example 4 are shown in Table 2.

Comparative example 5

914g (5.5mol) of terephthalic acid, 658g (4.5mol) of adipic acid, 1162g (10mol) of hexamethylenediamine, 12g (0.1mol) of blocking agent benzoic acid, 2g of catalyst sodium hypophosphite, and 2000g of deionized water were weighed and charged into a high-pressure reactor, and the temperature was raised to 205 ℃ to start holding the pressure (1.8MPa), and in the same manner as in example 3, when the temperature was raised to the holding pressure (1.8MPa) (263 ℃ C.), 6T salt and oligomer began to precipitate to inhibit the stirring of the reactor and stop the reaction. The raw material monomers of comparative example 5 and the comparative results are shown in table 2.

Comparative example 6

914g (5.5mol) of terephthalic acid, 658g (4.5mol) of adipic acid, 1162g (10mol) of hexamethylenediamine, 12g (0.1mol) of blocking agent benzoic acid, 2g of catalyst sodium hypophosphite, 2000g of deionized water, and 500g of ethanol (boiling point 78 ℃) were weighed and charged into a high-pressure reactor, and the temperature was raised to 205 ℃ to start holding pressure (1.8MPa), and in the same manner as in example 3, when the temperature was raised to the holding pressure (1.8MPa) temperature raising stage (261 ℃), 6T salt and oligomer began to precipitate, which prevented the reactor from stirring and stopped the reaction. The raw material monomers of comparative example 6 and the comparative results are shown in table 2.

Comparative example 7

914g (5.5mol) of terephthalic acid, 658g (4.5mol) of adipic acid, 1162g (10mol) of hexamethylenediamine, 12g (0.1mol) of blocking agent benzoic acid, 2g of catalyst sodium hypophosphite, 2000g of deionized water, and 500g of hydrogenated terphenyl (boiling point 352.8 ℃) were weighed into a high-pressure reactor, and the final product was in a swollen state and could not be smoothly pulled into pellets in the same manner as in example 3 except that. The raw material monomers of comparative example 7 and the comparative results are shown in table 2.

Table 1 formulation and performance test table of the examples

Table 2 formula and performance test table of comparative example

As can be seen from the experimental process comparing example 1 with comparative example 1, in example 1, 400g of N, N-dimethylformamide is added on the basis of comparative example 1, the rest of raw materials and polymerization conditions are completely the same, salt and oligomer are not precipitated and agglomerated in the pressure maintaining stage of 10T and can be polymerized smoothly in example 1, and salt and oligomer are precipitated in 10T and prevented from stirring in the reaction kettle and the reaction is stopped when comparative example 1 is carried out to 265 ℃ under the same pressure maintaining pressure. It is demonstrated that 400g of N, N-dimethylformamide added in example 1 indeed functions to increase the solubility of 10T salt and oligomer in the reaction system, and to prevent 10T salt and oligomer from being precipitated when the water content in the system is reduced, so that the polymerization process can be smoothly carried out. By testing the resulting product for melting point T_mAnd glass transition temperature T_gThe product performance is basically the same as that reported in the prior literature and that of the comparative example 2, which shows that the N, N-dimethylformamide added in the example 1 has no residue in the product and does not influence the service performance of the final product.

Comparative example 2 on the basis of comparative example 1, the holding pressure was increased from 2.0MPa to 2.8MPa, the remaining raw materials and polymerization conditions were completely the same, and no agglomeration was precipitated from the 10T salt and oligomer in the holding pressure stage, and the polymerization was smooth, indicating that increasing the holding pressure, increasing the moisture in the reaction system in the holding pressure stage could indeed prevent the 10T salt and oligomer from being precipitated, and the polymerization process proceeded smoothly. However, increasing the pressure-holding pressure requires increasing the pressure-holding grade of the production equipment and increasing the wall thickness of the equipment, which greatly increases the equipment investment and production cost and affects the market competitiveness of the product.

As can be seen from the experimental procedures comparing example 2 with comparative example 3, comparative example 4, and example 3 with comparative example 5, the polymerization was smoothly carried out under a lower pressure by adding an organic solvent in examples 2 and 3, while the precipitation of 6T salt and oligomer and the termination of the reaction occurred in comparative example 3 and comparative example 5 under the same raw materials and polymerization conditions at the stage of the pressure maintaining. In comparative example 4, the separation of 6T salt and oligomer was avoided by increasing the holding pressure based on example 3, and the reaction proceeded smoothly. The addition of the organic solvent in the embodiment of the invention can obviously improve the solubility of the amide salt and the oligomer in the pressure maintaining stage, reduce the pressure grade of polymerization equipment, save equipment investment and production cost, increase the market competitiveness of products, reduce safety risks and ensure the uniformity of a reaction system and the products.

Example 6 adding low boiling point ethanol, in the pressure keeping process prior to steam distillation, the residual amount in the system is very little, can not play the role of dissolving semi-aromatic amide salt and oligomer, the product appears agglomeration and reaction termination under lower pressure. Example 7 hydrogenated terphenyl with a high boiling point was added, and was not smoothly discharged during pressure maintaining and subsequent pressure releasing, resulting in a product that was always in a swollen state, and was not smoothly pulled into strands and cut into pellets, nor was smoothly produced and subjected to subsequent processing and application. Measurement of melting Point T_mAnd glass transition temperature T_gSince a large amount of organic solvent is present in the polymer, it functions as a plasticizer, and the melting point T is higher than that of example 3_mAnd glass transition temperature T_gAre significantly reduced.

In addition, the organic solvent added in the invention can not remain in a product system and influence the product quality, and the organic solvent is discharged in the later high-temperature pressure relief process, condensed and re-enters the next reaction process for recycling, so that the environment can not be influenced.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. It will be readily apparent to those skilled in the art that various modifications to these embodiments and the generic principles defined herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above-described embodiments. Those skilled in the art should appreciate that many modifications and variations are possible in light of the above teaching without departing from the scope of the invention.