CN114507344B

CN114507344B - Alcoholysis-resistant polyamide resin and preparation method and application thereof

Info

Publication number: CN114507344B
Application number: CN202011279967.XA
Authority: CN
Inventors: 陈召; 陈鑫博; 王晓华; 姚增文; 陈敏; 杨小娜
Original assignee: HUAFON GROUP CO LTD
Current assignee: HUAFON GROUP CO LTD
Priority date: 2020-11-16
Filing date: 2020-11-16
Publication date: 2024-01-23
Anticipated expiration: 2040-11-16
Also published as: CN114507344A

Abstract

The invention provides an alcoholysis-resistant polyamide resin, and a preparation method and application thereof. The polyamide resin comprises the following raw material components in percentage by mass: 97.8-99.98% of comonomer and 0.0043-0.011% of end-capping agent; the comonomer comprises the following components in percentage by mass: 80-92% of nylon 66 salt and 5-15% of aliphatic amide monomer; the molar concentration of carboxyl end groups in the polyamide resin is 10-25mmol/kg; the molar ratio of the terminal amino group to the terminal carboxyl group in the polyamide resin is more than or equal to 4:1. The alcoholysis-resistant polyamide resin is prepared by reacting a comonomer with a blocking agent to obtain a polyamide polymer, mixing the polyamide polymer with an optional alcoholysis-resistant agent, and then performing slicing and granulating. The alcoholysis-resistant polyamide resin provided by the invention has better alcoholysis resistance and better mechanical property, and is suitable for being used as a vehicle material.

Description

Alcoholysis-resistant polyamide resin and preparation method and application thereof

Technical Field

The invention belongs to the field of polyamide resin, and particularly relates to an alcoholysis-resistant polyamide resin, and a preparation method and application thereof.

Background

The polyamide is a generic term of thermoplastic resin containing repeated amide groups on a molecular main chain, the name of the polyamide is determined by the specific carbon number of a synthetic monomer, the polyamide is the most important engineering plastic, and the polyamide has better mechanical property, heat resistance, abrasion resistance, chemical resistance and self-lubricating property, and has lower friction coefficient, certain flame retardance and easy processing, so that the polyamide has wide product application, almost covers each field and is the most widely applied variety in five engineering plastics. However, due to the existence of amide groups, in the environment with higher temperature and higher humidity, the polyamide is easy to generate hydrolysis reaction, and once the hydrolysis reaction occurs, the polyamide product can be rapidly degraded, so that the product performance is greatly reduced, the service life is reduced, and the application value is lost, so how to prepare the polyamide resin with hydrolysis and alcoholysis resistance is important.

CN102516761a discloses a hydrolysis-resistant alcoholysis nylon 66 composite material and a preparation method thereof. The hydrolysis-resistant alcoholysis nylon 66 composite material prepared by the technology comprises, by weight, 51.8-84.5 parts of nylon resin, 15-40 parts of chopped glass fibers, 0.1-0.6 part of nucleating agent, 0.1-0.6 part of heat stabilizer, 0.1-1.0 part of alcoholysis-resistant auxiliary agent, 0.1-5 parts of barrier agent and 0.1-1.0 part of lubricant, and the preparation method comprises the following steps: uniformly mixing the nylon 66 resin, the antioxidant, the hydrolysis inhibitor, the blocking agent, the nucleating agent and the lubricant which are dried in advance at a high speed, and then feeding the mixture and the glass fiber into a double-screw extruder for extrusion granulation. The nylon 66 composite material prepared by the technical scheme has good high-temperature thermal oxidation aging resistance and ethylene glycol and aqueous solution corrosion resistance, but the properties of nylon resin are modified.

CN101613527a discloses an alcoholysis-resistant nylon composite material and a preparation method thereof, and the nylon composite material prepared by the technology contains nylon, short glass fiber, glass fiber exposure prevention regulating auxiliary agent, nucleating agent, coloring agent, heat stabilizer and alcoholysis-resistant auxiliary agent, and has excellent physical and chemical properties. The short glass fiber adopted in the technical scheme is treated by a silane coupling agent, and the surface of the short glass fiber is coated with a silane impregnating compound so as to improve the alcoholysis resistance of the nylon composite material, but the alcoholysis resistance of the alcoholysis resistance nylon composite material is mainly provided by the short glass fiber treated by the silane coupling agent and the property of the nylon resin is not improved.

CN106987122a discloses a hydrolysis-resistant short glass fiber reinforced nylon 66 and a preparation method thereof. The hydrolysis-resistant short glass fiber reinforced nylon 66 prepared by the technology comprises the following raw material components in parts by weight: 35-50 parts of nylon 66, 50-60 parts of glass fiber, 0.5-1.0 part of antioxidant, 1.0 part of black matrix, 0.1-0.5 part of calcium stearate and 0.1-0.5 part of maleic anhydride grafted polyethylene wax; the preparation steps comprise weighing, mixing, stirring, melt extrusion, cooling, drying and the like. According to the technical scheme, the maleic anhydride grafted polyethylene wax with high molecular weight is added, so that the overall polarity of the material is reduced, and the water absorption capacity of the material is reduced, so that the hydrolysis resistance of the short glass fiber reinforced nylon 66 is improved, but the properties of the nylon 66 resin are not improved.

Thus, the method for improving the alcoholysis resistance of the nylon composite material in the prior art is generally to add an alcoholysis resistance aid or filler, such as glass fiber, to the nylon material; the introduction of the alcoholysis-resistant auxiliary agent or filler not only can influence the microcosmic continuity of the nylon material and lead to the change of mechanical properties, but also can increase the difficulty of polymer processing and increase the preparation cost. Therefore, how to modify the polyamide resin to have better alcoholysis resistance and excellent mechanical properties without adding other alcoholysis resistance aids has become a current urgent problem.

Disclosure of Invention

Aiming at the defects existing in the prior art, the invention aims to provide an alcoholysis-resistant polyamide resin, and a preparation method and application thereof. According to the invention, the molar concentration of terminal carboxyl groups and the molar ratio of terminal amino groups to terminal carboxyl groups in the polyamide resin are limited, so that the occurrence of hydrolysis/alcoholysis reaction is reduced, and the prepared polyamide resin has excellent alcoholysis resistance and good mechanical properties, and simultaneously, the influence of secondary melting on the performance of a polyamide product is reduced.

To achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the invention provides an alcoholysis-resistant polyamide resin, which comprises the following raw material components in percentage by mass: 97.8-99.98% of comonomer and 0.0043-0.011% of end-capping agent;

the copolymerization unit comprises the following components in percentage by mass: 80-92% of nylon 66 salt and 5-15% of aliphatic amide monomer;

the molar concentration of carboxyl end groups in the polyamide resin is 10-25mmol/kg;

the molar ratio of terminal amino groups to terminal carboxyl groups in the polyamide resin is more than or equal to 4:1, such as 4.2:1, 4.5:1, 4.8:1, 5:1, 5.2:1, 5.5:1, 5.8:1, 6:1, 6.2:1, 6.5:1, 6.8:1, 7:1, 7.2:1, 7.5:1, 7.8:1, 8:1, 8.2:1, 8.5:1, 8.7:1, etc.

In the present invention, the polyamide resin is prepared by specific raw material components and proportions, and the molar concentration of the terminal carboxyl groups and the molar ratio of the terminal amino groups to the terminal carboxyl groups of the polyamide resin are further limited by controlling the content of the end capping agent. When the molar concentration of the terminal carboxyl groups in the polyamide resin is 10-25mmol/kg and the molar ratio of the terminal amino groups to the terminal carboxyl groups is more than or equal to 4:1, the polyamide resin has excellent hydrolysis resistance. When the molar concentration of terminal carboxyl groups in the polyamide resin is small or large or the molar ratio of terminal amino groups to terminal carboxyl groups is less than 4:1, the polyamide resin is inferior in hydrolysis resistance.

In the present invention, the mass percentage of the comonomer may be 97.8%, 98.2%, 98.5%, 98.8%, 99%, 99.3%, 99.5% or 99.98%, etc.

The mass percent of the end-capping agent may be 0.0043%, 0.005%, 0.0055%, 0.006%, 0.0065%, 0.007%, 0.0075%, 0.008%, 0.0085%, 0.009%, 0.0095%, 0.01%, or 0.011%, etc.

The mass percent of the nylon 66 salt can be 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91% or 92% or the like.

The mass percentage of the aliphatic amide monomer may be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%, etc.

The molar concentration of the terminal carboxyl groups in the polyamide resin may be 10mmol/kg, 12mmol/kg, 15mmol/kg, 18mmol/kg, 20mmol/kg, 23mmol/kg, 25mmol/kg, or the like.

Since the reaction of an acid with an amine to form a polymer polyamide is a reversible reaction, the reaction degree cannot reach 100%, and therefore, the molar concentration of terminal carboxyl groups in the polyamide resin is hardly lower than 10mmol/kg; when the molar concentration of the terminal carboxyl groups is large, the acid catalysis accelerates the hydrolysis of the polyamide, so that the hydrolysis resistance (alcoholysis) of the prepared polyamide resin is reduced.

The following is a preferred technical scheme of the present invention, but not a limitation of the technical scheme provided by the present invention, and the following preferred technical scheme can better achieve and achieve the objects and advantages of the present invention.

As a preferable technical scheme of the invention, the aliphatic amide monomer is nylon salt and/or lactam.

Preferably, at least one of diamine and diacid for preparing the nylon salt has 7 to 15 carbon atoms (for example, 7, 8, 9, 10, 11, 12, 13, 14 or 15), and more preferably 8 to 12.

Illustratively, the diamine from which the nylon salt is prepared is selected from the group consisting of nonylenediamine, decylenediamine, dodecylenediamine; the diacid is selected from azelaic acid, sebacic acid, and dodecanedioic acid.

Preferably, the nylon salt is selected from any one or a combination of at least two of nylon 610 salt, nylon 612 salt and nylon 1212 salt.

Preferably, the number of carbon atoms of the lactam is 7 to 15 (e.g., 7, 8, 9, 10, 11, 12, 13, 14, or 15), and more preferably 8 to 12.

Preferably, the lactam is decalactam and/or dodecalactam.

According to the invention, through copolymerization of the aliphatic amide monomer with specific carbon atoms and the nylon 66 salt, the alcoholysis resistance of the polyamide resin can be improved, and if the aliphatic amide monomer has fewer carbon atoms, the prepared polyamide resin has poorer alcoholysis resistance; if the aliphatic amide monomer has a large number of carbon atoms, the mechanical properties of the prepared polyamide resin are poor.

As a preferable technical scheme of the invention, the end capping agent is monoamine and/or diamine.

Preferably, the monoamine is selected from any one or a combination of at least two of ammonia monohydrate, ethylamine, n-propylamine, n-butylamine, n-pentylamine, n-hexylamine or benzylamine.

Preferably, the diamine is selected from any one or a combination of at least two of pentanediamine, hexanediamine, butanediamine, decanediamine or dodecanediamine.

Preferably, the molar concentration of the terminal amino groups in the polyamide resin is 64-140mmol/kg, and for example, 64mmol/kg, 70mmol/kg, 75mmol/kg, 80mmol/kg, 85mmol/kg, 90mmol/kg, 95mmol/kg, 100mmol/kg, 105mmol/kg, 110mmol/kg, 115mmol/kg, 120mmol/kg, 125mmol/kg, 130mmol/kg, 135mmol/kg, 140mmol/kg, or the like can be used.

Preferably, the molar ratio of terminal amino groups to terminal carboxyl groups in the polyamide resin is 4:1-10:1, and may be, for example, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1, 9.5:1, or 10:1, etc.

As a preferred embodiment of the present invention, the comonomer further comprises an aromatic amide monomer.

Preferably, the aromatic amide monomer is selected from any one or a combination of at least two of nylon 6I salt, nylon 6T salt or nylon MXD6 salt.

Preferably, the aromatic amide monomer accounts for 3-5% of the mass of the comonomer, and may be, for example, 3%, 3.2%, 3.4%, 3.6%, 3.8%, 4%, 4.2%, 4.4%, 4.6%, 4.8% or 5%.

According to the invention, the aromatic amide monomer is used, so that not only can the hydrolysis condition of the polyamide resin be destroyed, but also the mechanical property of the polyamide resin can be enhanced, and therefore, the polyamide resin formed by copolymerizing the aromatic amide monomer, nylon 66 salt and the aliphatic amide monomer has lower water absorption, better hydrolysis resistance and better mechanical property.

Preferably, the raw material component of the polyamide resin further comprises an alcoholysis-resistant agent.

Preferably, the alcoholysis-resistant agent is selected from any one or a combination of at least two of bis (2, 6-diisopropylphenyl) carbodiimide, macromolecular hindered amine and phosphate compounds, epoxy polymer hydrolysis-resistant agents and polycarbodiimides.

Preferably, the alcoholysis-resistant agent accounts for 0.1-2% of the mass of the polyamide resin raw material component, and may be, for example, 0.1%, 0.3%, 0.5%, 0.7%, 1%, 1.2%, 1.4%, 1.6%, 1.8% or 2%.

In the present invention, the raw material component of the polyamide resin further includes a catalyst for accelerating the reaction rate of the raw material of the polyamide resin, wherein the catalyst used in the present invention is a catalyst known in the art, and may be exemplified by sodium hypophosphite, and the catalyst content may be exemplified by 0.01 to 0.2% by mass, 0.01%, 0.02%, 0.04%, 0.06%, 0.08%, 0.1%, 0.12%, 0.14%, 0.16%, 0.18% or 0.2% by mass of the raw material component of the polyamide resin.

In a preferred embodiment of the present invention, the polyamide resin has a relative viscosity of 2.4 to 3.1, and may be, for example, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3 or 3.1.

Preferably, the polyamide resin has a relative viscosity of 2.55 to 2.6, and may be, for example, 2.55, 2.56, 2.57, 2.58, or 2.6, etc.

In a second aspect, the present invention provides a method for preparing the above-mentioned alcoholysis-resistant polyamide resin, comprising the steps of:

(1) Carrying out reaction on a comonomer and a blocking agent to obtain a polyamide polymer;

(2) And (3) mixing the polyamide polymer obtained in the step (1) and an optional alcoholysis-resistant agent, and then carrying out slicing and granulating to obtain the alcoholysis-resistant polyamide resin.

After the polyamide polymer and the optional alcoholysis-resistant agent are mixed and subjected to slicing and granulation, the molar concentration of the carboxyl end group and the molar concentration of the amino end group of the prepared polyamide resin cannot be tested, so that the molar concentration of the carboxyl end group and the molar concentration of the amino end group of the polyamide resin refer to the molar concentration of the carboxyl end group and the molar concentration of the amino end group in the polyamide polymer obtained in the step (1).

As a preferred embodiment of the invention, the comonomer is a concentrated comonomer solution.

Preferably, the solvent of the comonomer solution is desalted water.

Preferably, the concentration method is to perform concentration in a concentration tank.

Preferably, the pressure of the concentration tank is 0.2-0.3MPa, for example, 0.2MPa, 0.22MPa, 0.24MPa, 0.26MPa, 0.28MPa or 0.3MPa, etc.

Preferably, the concentrated comonomer solution has a mass concentration of 75 to 85%, for example 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84% or 85% etc.

Preferably, the capping agent is a capping agent solution.

Preferably, the solvent of the capping agent solution is desalted water.

Preferably, the mass concentration of the capping agent solution is 45-55%, for example, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, or the like.

As a preferred embodiment of the present invention, the temperature of the reaction in the step (1) is 250 to 270℃and may be, for example, 250℃252℃255℃258℃260℃263℃265℃267℃267℃270 ℃.

Preferably, the reaction in the step (1) comprises the steps of heating up, pressurizing, heating up under pressure, releasing pressure and vacuumizing.

Preferably, in the heating and boosting, the heating rate is 1.5-2 ℃/min, for example, 1.5 ℃/min, 1.6 ℃/min, 1.7 ℃/min, 1.8 ℃/min, 1.9 ℃/min or 2 ℃/min, etc.

Preferably, the heating and pressure increasing time is 15-25min, for example, 15min, 16min, 17min, 18min, 19min, 20min, 21min, 22min, 23min, 24min or 25min, etc.

Preferably, the pressure of the temperature rise and the pressure increase is 1.6-1.85MPa, for example, 1.6MPa, 1.68MPa, 1.72MPa, 1.75MPa, 1.77MPa, 1.8MPa, 1.82MPa, 1.85MPa or the like.

Preferably, the pressure of the pressure maintaining is 1.6-1.85MPa, for example, 1.6MPa, 1.67MPa, 1.71MPa, 1.74MPa, 1.77MPa, 1.8MPa, 1.82MPa, 1.85MPa or the like can be used.

Preferably, the dwell time is 60-75min, for example 60min, 62min, 65min, 67min, 70min, 72min or 75min, etc.

Preferably, the temperature of the pressure maintaining and temperature increasing is 250-270 ℃, and can be 250 ℃, 252 ℃, 255 ℃, 258 ℃, 260 ℃, 263 ℃, 265 ℃, 267 ℃, 270 ℃ or the like.

Preferably, the pressure relief comprises a first pressure relief stage, a second pressure relief stage and a third pressure relief stage.

Preferably, the pressure of the reaction after the first pressure relief stage is 0.4 to 0.5MPa (for example, may be 0.4MPa, 0.42MPa, 0.44MPa, 0.46MPa, 0.48MPa or 0.5MPa, etc.), the pressure of the reaction after the second pressure relief stage is 0.15 to 0.25MPa (for example, may be 0.15MPa, 0.17MPa, 0.19MPa, 0.21MPa, 0.23MPa or 0.25MPa, etc.), and the pressure of the reaction after the third pressure relief stage is 0.095 to 0.15MPa (for example, may be 0.095MPa, 0.097MPa, 0.099MPa, 0.11MPa, 0.13MPa or 0.15MPa, etc.).

Preferably, the pressure relief rate is 0.01-0.05MPa/min, for example, 0.01MPa/min, 0.015MPa/min, 0.02MPa/min, 0.025MPa/min, 0.03MPa/min, 0.035MPa/min, 0.04MPa/min, 0.045MPa/min, 0.01MPa/min, etc.

Preferably, after the vacuum-pumping stage, the vacuum degree of the reaction is-0.035 to-0.025 MPa, such as-0.035 MPa, -0.033MPa, -0.03MPa, -0.027MPa or-0.025 MPa.

Preferably, the vacuum degree is maintained for 7-12min, for example, 7min, 8min, 9min, 10min, 11min or 12min, etc.

Preferably, the reaction is carried out in the presence of nitrogen.

Preferably, in step (2), the method of mixing is mixing via a mixer.

Preferably, the mixers are feed mixers and static mixers.

As a preferable technical scheme of the invention, the preparation method comprises the following steps:

(1) Adding a comonomer solution into a concentration tank with the pressure of 0.2-0.3MPa for concentration, reacting the comonomer solution with the mass concentration of 75-85%, a capping reagent solution with the mass concentration of 45-55% and a catalyst in a nitrogen atmosphere, and obtaining a polyamide polymer after heating, pressurizing, maintaining pressure, heating, releasing pressure and vacuumizing; wherein, when heating up and boosting, the heating up rate is 1.5-2 ℃/min, the time is 15-25min, the heating up and boosting pressure is 1.6-1.85MPa, the time is 60-75min, the temperature of maintaining and boosting is 250-270 ℃, the pressure relief comprises a first pressure relief stage, a second pressure relief stage and a third pressure relief stage, the pressure of the reaction is 0.4-0.5MPa after the first pressure relief stage, the pressure of the reaction is 0.15-0.25MPa after the second pressure relief stage, the pressure of the reaction is 0.095-0.15MPa after the third pressure relief stage, the pressure relief rate is 0.01-0.05MPa/min, the vacuum degree of the reaction is-0.035-0.025 MPa after vacuumizing, and the time for maintaining the vacuum degree is 7-12min;

(2) And (3) mixing the polyamide polymer obtained in the step (1) with an optional alcoholysis-resistant agent through a feed mixer and a static mixer, and then performing slicing and granulation to obtain the alcoholysis-resistant polyamide resin.

In a third aspect, the present invention provides the use of the above-described alcoholysis-resistant polyamide resin as a material for vehicles.

Compared with the prior art, the invention has at least the following beneficial effects:

according to the invention, the alcoholysis-resistant polyamide resin is prepared by specific raw material components and proportions, the molar concentration of the terminal carboxyl groups and the molar ratio of the terminal amino groups to the terminal carboxyl groups of the polyamide resin are particularly limited, and the occurrence probability of hydrolysis/alcoholysis reaction of the polyamide resin is reduced, so that the prepared alcoholysis-resistant polyamide resin has better hydrolysis resistance and better mechanical property, the tensile strength is 93-112 MPa, the alcoholysis aging-resistant tensile strength is 51-73 MPa, the tensile strength retention rate is not lower than 52%, and the surface property is good, and is suitable for use.

Detailed Description

The technical scheme of the invention is further described by the following specific examples. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.

Some sources of raw materials in examples and comparative examples are as follows:

polycarbodiimide: shanghai You En chemical Co., ltd., UN-03;

macromolecular hindered amine and phosphate compounds: hiplamide AO-200, available from Shanghai, rajia, inc.;

hydrolysis resistance agent for epoxy polymers: sandwell AH81, a company of Sanhe chemical Co., ltd.

Example 1

The embodiment provides an alcoholysis-resistant polyamide resin (with a relative viscosity of 2.40), which comprises the following raw material components in percentage by mass:

wherein the comonomer comprises the following components in percentage by mass: 92% of nylon 66 salt, 5% of nylon 612 salt and 3% of nylon MXD6 salt, wherein the alcoholysis-resistant agent consists of bis (2, 6-diisopropylphenyl) carbodiimide and polycarbodiimide (UN-03) according to a mass ratio of 1:2.

The preparation method of the alcoholysis-resistant polyamide resin comprises the following steps:

(1) Adding a comonomer solution with the mass concentration of 57% into a concentration tank with the pressure of 0.25MPa for concentration, reacting the comonomer solution with the mass concentration of 80%, the hexamethylenediamine solution with the mass concentration of 50% and sodium hypophosphite in a nitrogen atmosphere after concentration, and obtaining a polyamide polymer after heating up, pressurizing, maintaining pressure, heating up, releasing pressure and vacuumizing; wherein, when heating up and boosting, the heating up rate is 1.8 ℃/min, the time is 20min, the heating up and boosting pressure is 1.7MPa, the pressure is 1.85MPa, the time is 65min, the temperature for maintaining and boosting is 260 ℃, the pressure relief comprises a first pressure relief stage, a second pressure relief stage and a third pressure relief stage, the pressure for reaction is 0.45MPa after passing through the first pressure relief stage, the pressure relief rate is 0.045MPa/min, the pressure for reaction is 0.2MPa after passing through the second pressure relief stage, the pressure relief rate is 0.03MPa/min, the pressure for reaction is 0.1MPa after passing through the third pressure relief stage, the pressure relief rate is 0.0102MPa/min, the vacuum degree for reaction is-0.025 MPa after vacuumizing, and the time for maintaining the vacuum degree is 10min;

(2) Mixing the polyamide polymer obtained in the step (1) with an alcoholysis-resistant agent through a feeding mixer and a static mixer, and then carrying out slicing and granulation to obtain alcoholysis-resistant polyamide resin;

wherein the concentration of carboxyl end groups of the polyamide resin is 14mmol/kg, the concentration of amino end groups is 140mmol/kg, and the molar ratio of the amino end groups to the carboxyl end groups is 10:1.

Example 2

The embodiment provides an alcoholysis-resistant polyamide resin (with a relative viscosity of 2.60), which comprises the following raw material components in percentage by mass:

wherein the comonomer comprises the following components in percentage by mass: 80% of nylon 66 salt, 15% of nylon 610 salt and 5% of nylon 6T salt, wherein the alcoholysis-resistant agent consists of high-efficiency macromolecular hindered amine and a phosphate compound (Hiplamide A0-200) and an epoxy polymer hydrolysis-resistant agent (Sanwell AH 81) according to the mass ratio of 1:1.

(1) Adding a nylon salt solution with the mass concentration of 56.75% and a laurolactam solution with the mass concentration of 50% into a concentration tank with the pressure of 0.25MPa for concentration, reacting a comonomer solution with the mass concentration of 80% after concentration, a capping agent solution with the mass concentration of 50% and sodium hypophosphite under the protection of nitrogen, and obtaining a polyamide polymer after heating up, pressurizing, maintaining pressure, heating up, releasing pressure and vacuumizing; wherein, when heating up and boosting, the heating up rate is 1.8 ℃/min, the time is 20min, the heating up and boosting pressure is 1.7MPa, the pressure is 1.8MPa, the time is 60min, the temperature for maintaining and boosting is 260 ℃, the pressure relief comprises a first pressure relief stage, a second pressure relief stage and a third pressure relief stage, the pressure of the reaction is 0.45MPa after passing through the first pressure relief stage, the pressure relief rate is 0.05MPa/min, the pressure of the reaction is 0.2MPa after passing through the second pressure relief stage, the pressure relief rate is 0.03MPa/min, the pressure of the reaction is 0.1MPa after passing through the third pressure relief stage, the pressure relief rate is 0.01MPa/min, the vacuum degree of the reaction is-0.035 MPa after vacuumizing, and the time for maintaining the vacuum degree is 10min;

wherein the concentration of the carboxyl end groups of the polyamide resin is 25mmol/kg, the concentration of the amino end groups is 100mmol/kg, and the molar ratio of the amino end groups to the carboxyl end groups is 4:1.

Example 3

The embodiment provides an alcoholysis-resistant polyamide resin (with a relative viscosity of 3.10), which comprises the following raw material components in percentage by mass:

wherein the comonomer comprises the following components in percentage by mass: 86% nylon 66 salt, 10% nylon 612 salt and 4% nylon 6I salt.

(1) Adding a comonomer solution with the mass concentration of 57% into a concentration tank with the pressure of 0.2MPa for concentration, reacting the comonomer solution with the mass concentration of 75%, an ammonia monohydrate solution with the mass concentration of 45% and sodium hypophosphite under the protection of nitrogen, and obtaining a polyamide polymer after heating up, pressurizing, maintaining pressure, heating up, releasing pressure and vacuumizing; wherein, when heating up and boosting, the heating up rate is 1.7 ℃/min, the time is 25min, the heating up and boosting pressure is 1.85MPa, the time is 75min, the temperature for maintaining and boosting is 250 ℃, the pressure relief comprises a first pressure relief stage, a second pressure relief stage and a third pressure relief stage, the pressure of the reaction is 0.4MPa after passing through the first pressure relief stage, the pressure relief rate is 0.045MPa/min, the pressure of the reaction is 0.15MPa after passing through the second pressure relief stage, the pressure relief rate is 0.03MPa/min, the pressure of the reaction after passing through the third pressure relief stage is 0.095MPa, the pressure relief rate is 0.0102MPa/min, the vacuum degree of the reaction after vacuumizing is-0.03 MPa, and the time for maintaining the vacuum degree is 12min;

(2) Mixing the polyamide polymer obtained in the step (1) with polycarbodiimide (UN-03) through a feeding mixer and a static mixer, and then performing slicing and granulation to obtain the alcoholysis-resistant polyamide resin;

wherein the concentration of carboxyl end groups of the polyamide resin is 10mmol/kg, the concentration of amino end groups is 80mmol/kg, and the molar ratio of the amino end groups to the carboxyl end groups is 8:1.

Example 4

wherein the comonomer comprises the following components in percentage by mass: 90% of nylon 66 salt and 10% of nylon 612 salt.

(1) Adding a nylon salt solution with the mass concentration of 56.75% and a caprolactam solution with the mass concentration of 50% into a concentration tank with the pressure of 0.3MPa for concentration, reacting a comonomer solution with the mass concentration of 85% after concentration, a pentanediamine solution with the mass concentration of 55% and sodium hypophosphite under the protection of nitrogen, and obtaining a polyamide polymer after heating up, pressurizing, maintaining pressure, heating up, releasing pressure and vacuumizing; wherein, when heating up and boosting, the heating up rate is 2 ℃/min, the time is 15min, the heating up and boosting pressure is 1.6MPa, the time is 72min, the temperature for maintaining and boosting is 270 ℃, the pressure relief comprises a first pressure relief stage, a second pressure relief stage and a third pressure relief stage, the pressure of the reaction is 0.5MPa after passing through the first pressure relief stage, the pressure relief rate is 0.045MPa/min, the pressure of the reaction is 0.25MPa after passing through the second pressure relief stage, the pressure relief rate is 0.03MPa/min, the pressure of the reaction is 0.15MPa after passing through the third pressure relief stage, the pressure relief rate is 0.0102MPa/min, the vacuum degree of the reaction is-0.025 MPa after vacuumizing, and the time for maintaining the vacuum degree is 10min;

(2) Mixing the polyamide polymer obtained in the step (1) with an epoxy polymer hydrolysis inhibitor (Sanwell AH 81) through a feed mixer and a static mixer, and then performing slicing and granulation to obtain an alcoholysis-resistant polyamide resin;

wherein the concentration of carboxyl end groups of the polyamide resin is 18mmol/kg, the concentration of amino end groups is 108mmol/kg, and the molar ratio of the amino end groups to the carboxyl end groups is 6:1.

Example 5

wherein the comonomer comprises the following components in percentage by mass: 90% of nylon 66 salt, 5% of decalactam and 5% of nylon MXD6 salt, wherein the end capping agent consists of ammonia monohydrate and hexamethylenediamine in a mass ratio of 1:1.7.

(1) Adding a comonomer solution with the mass concentration of 57.3% into a concentration tank with the pressure of 0.23MPa for concentration, reacting the comonomer solution with the mass concentration of 82% after concentration, a hexamethylenediamine solution with the mass concentration of 48% and sodium hypophosphite under the protection of nitrogen, and obtaining a polyamide polymer after heating up, pressurizing, maintaining pressure, heating up, releasing pressure and vacuumizing; wherein, when heating up and boosting, the heating up rate is 1.9 ℃/min, the time is 22min, the heating up and boosting pressure is 1.82MPa, the time is 68min, the temperature for maintaining and boosting is 265 ℃, the pressure relief comprises a first pressure relief stage, a second pressure relief stage and a third pressure relief stage, the pressure of the reaction is 0.48MPa after passing through the first pressure relief stage, the pressure relief rate is 0.045MPa/min, the pressure of the reaction is 0.21MPa after passing through the second pressure relief stage, the pressure relief rate is 0.03MPa/min, the pressure of the reaction is 0.1MPa after passing through the third pressure relief stage, the pressure relief rate is 0.0102MPa/min, the vacuum degree of the reaction is-0.025 MPa after vacuumizing, and the time for maintaining the vacuum degree is 10min;

(2) Mixing the polyamide polymer obtained in the step (1) with bis (2, 6-diisopropylphenyl) carbodiimide through a feed mixer and a static mixer, and then carrying out slicing and granulation to obtain an alcoholysis-resistant polyamide resin;

wherein the concentration of the carboxyl end groups of the polyamide resin is 16mmol/kg, the concentration of the amino end groups is 64mmol/kg, and the molar ratio of the amino end groups to the carboxyl end groups is 4:1.

Example 6

wherein the comonomer comprises the following components in percentage by mass: 82% of nylon 66 salt, 15% of nylon 1212 salt and 3% of nylon 6T salt; the end capping agent consists of n-hexylamine and hexamethylenediamine in a mass ratio of 1:0.85.

The preparation method of the above-mentioned alcoholysis-resistant polyamide resin is the same as in example 1.

Wherein the concentration of carboxyl end groups of the polyamide resin is 12mmol/kg, the concentration of amino end groups is 72mmol/kg, and the molar ratio of the amino end groups to the carboxyl end groups is 6:1.

Example 7

This example provides an alcoholysis-resistant polyamide resin (relative viscosity: 2.60), which differs from example 2 only in that the raw material component contains 2.0% by mass of an alcoholysis-resistant agent, 97.8% by mass of a comonomer, 0.193% by mass of sodium hypophosphite, and the other conditions are the same as in example 2, and the concentration of terminal carboxyl groups of the polyamide resin produced is 25mmol/kg, the concentration of terminal amino groups is 100mmol/kg, and the molar ratio of terminal amino groups to terminal carboxyl groups is 4:1.

Example 8

This example provides an alcoholysis-resistant polyamide resin (relative viscosity: 2.60), which differs from example 5 only in that the raw material component does not contain bis (2, 6-diisopropylphenyl) carbodiimide, the mass percentage of the comonomer is 99.98%, and the other conditions are the same as in example 5, and the concentration of terminal carboxyl groups, the concentration of terminal amino groups and the molar ratio of terminal amino groups to terminal carboxyl groups of the prepared polyamide resin are 16mmol/kg, 64mmol/kg and 4:1.

Comparative example 1

This comparative example provides an alcoholysis-resistant polyamide resin (relative viscosity: 2.60) differing from example 6 only in that the comonomer does not contain nylon 1212 salt and nylon 6T salt, the mass percentage of nylon 66 salt is 100%, the other conditions are the same as in example 6, the concentration of terminal carboxyl groups of the polyamide resin obtained is 12mmol/kg, the concentration of terminal amino groups is 72mmol/kg, and the molar ratio of terminal amino groups to terminal carboxyl groups is 6:1.

Comparative example 2

This comparative example provides an alcoholysis-resistant polyamide resin (relative viscosity: 2.60), which differs from example 4 only in that no pentylene diamine is added to the raw material components, the mass percentage of nylon 66 salt is 90.5%, and the other conditions are the same as in example 4, and the concentration of terminal carboxyl groups, the concentration of terminal amino groups, and the molar ratio of terminal amino groups to terminal carboxyl groups of the polyamide resin produced are 84mmol/kg, 42mmol/kg, and 1:2.

Comparative example 3

This comparative example provides an alcoholysis-resistant polyamide resin (relative viscosity: 2.60), which is different from example 2 in that hexamethylenediamine is added in an amount of 0.0035%, sodium hypophosphite is present in a mass percentage of 0.1035%, and the polyamide resin obtained by the same conditions as in example 2 has a carboxyl end group concentration of 42mmol/kg, an amino end group concentration of 84mmol/kg and a molar ratio of amino end group to carboxyl end group of 2:1.

Comparative example 4

This comparative example provides an alcoholysis-resistant polyamide resin (relative viscosity: 2.60), which differs from example 5 only in that the mass percentage of the end-capping agent is 0.0037%, the mass percentage of sodium hypophosphite is 0.0163%, wherein the end-capping agent consists of ammonia monohydrate and hexamethylenediamine in a mass ratio of 1.52:1, and the other conditions are the same as example 5, the concentration of terminal carboxyl groups of the polyamide resin obtained is 22mmol/kg, the concentration of terminal amino groups is 66mmol/kg, and the molar ratio of terminal amino groups to terminal carboxyl groups is 3:1.

The performance of the polyamide resin provided in the above examples was tested as follows:

tensile strength test: according to national standard GB/T1040.1-2018, the size of the sample is 150 multiplied by 10 multiplied by 4mm, and the stretching speed is 5mm/min;

alcoholysis resistance test: placing the sample in a mixed solution of glycol and water in a volume ratio of 1:1, soaking for 48 hours at 135 ℃, and evaluating the alcoholysis resistance by using a tensile strength retention rate;

surface properties: observing the shape change of the sample after the alcoholysis resistance test, and if the sample has no obvious deformation, the surface is good without damage; if the sample is not obviously deformed, the surface is slightly damaged, namely, the surface is slightly worse.

Tensile strength retention: tensile strength retention = resistance to alcoholysis aging tensile strength/tensile strength x 100%.

The results of the above performance tests are shown in table 1 below:

TABLE 1

As can be seen from the results in Table 1, the polyamide resin is prepared by specific raw material components and proportions, the molar concentration of the terminal carboxyl groups and the molar ratio of the terminal amino groups to the terminal carboxyl groups of the polyamide resin are particularly limited, and the probability of occurrence of hydrolysis/alcoholysis reaction of the polyamide resin is reduced, so that the polyamide resin has better hydrolysis resistance and better mechanical properties. The polyamide resin prepared by the invention has the tensile strength of 93-112 MPa, the alcoholysis aging resistance tensile strength of 51-73 MPa, the tensile strength retention rate of not less than 52%, and good surface performance, and is suitable for use.

Compared with example 6, if only nylon 66 salt is contained in the comonomer of the polyamide resin, and the polyamide resin does not contain aliphatic amide resin and aromatic amide resin (comparative example 1), the prepared polyamide resin has poorer mechanical properties, tensile strength of 90MPa, alcoholysis aging resistant tensile strength of 46MPa, tensile strength retention of 51 percent and poorer surface properties.

Compared with example 4, if the raw material component of the polyamide resin does not contain the end-capping agent (comparative example 2), the prepared polyamide resin has poor alcoholysis resistance, the alcoholysis aging resistance tensile strength is 37MPa, and the tensile strength retention is lower by 40%.

Compared with example 2, if the content of the end-capping agent in the raw material component of the polyamide resin is small (comparative example 3), the concentration of the terminal carboxyl groups in the prepared polyamide resin is large, and the molar ratio of the terminal amino groups to the terminal carboxyl groups is small, so that the polyamide resin has poor alcoholysis resistance, has an alcoholysis aging resistance tensile strength of 39MPa and a tensile strength retention rate of 42%.

Compared with example 5, if the content of the end-capping agent in the raw material components of the polyamide resin is small, the molar ratio of the end amino groups to the end carboxyl groups of the prepared alcoholysis-resistant polyamide resin is small (comparative example 4), the mechanical property is poor, the tensile strength is 89MPa, the alcoholysis aging-resistant tensile strength is 41MPa, and the tensile strength retention is 46%.

The applicant states that the detailed process equipment and process flows of the present invention are described by the above examples, but the present invention is not limited to, i.e., does not mean that the present invention must be practiced in dependence upon, the above detailed process equipment and process flows. It should be apparent to those skilled in the art that any modification of the present invention, equivalent substitution of raw materials for the product of the present invention, addition of auxiliary components, selection of specific modes, etc., falls within the scope of the present invention and the scope of disclosure.

Claims

1. An alcoholysis-resistant polyamide resin is characterized by comprising the following raw material components in percentage by mass: 97.8-99.98% of comonomer and 0.0043-0.011% of end-capping agent;

the comonomer comprises the following components in percentage by mass: 80-92% of nylon 66 salt and 5-15% of aliphatic amide monomer;

the molar ratio of the terminal amino group to the terminal carboxyl group in the polyamide resin is more than or equal to 4:1;

the aliphatic amide monomer is nylon salt and/or lactam, at least one of diamine or diacid for preparing the nylon salt has 7-15 carbon atoms, and the lactam has 7-15 carbon atoms;

the end capping agent is monoamine and/or diamine;

the raw material components of the polyamide resin also comprise an alcoholysis-resistant agent;

the alcoholysis resistant agent accounts for 0.1-2% of the mass of the polyamide resin raw material.

2. The alcoholysis-resistant polyamide resin according to claim 1 characterized in that at least one of diamine or diacid for preparing the nylon salt has 8 to 12 carbon atoms.

3. The alcoholysis-resistant polyamide resin according to claim 2 characterized in that the nylon salt is selected from any one or a combination of at least two of nylon 610 salt, nylon 612 salt, nylon 1212 salt.

4. The alcoholysis-resistant polyamide resin according to claim 1 characterized in that the number of carbon atoms of the lactam is 8-12.

5. The alcoholysis-resistant polyamide resin as in claim 4 wherein the lactam is decyllactam and/or lauryllactam.

6. The alcoholysis-resistant polyamide resin according to claim 1 characterized in that the monoamine is selected from any one or a combination of at least two of ammonia monohydrate, ethylamine, n-propylamine, n-butylamine, n-pentylamine, n-hexylamine, or benzylamine.

7. The alcoholysis-resistant polyamide resin according to claim 1 characterized in that the diamine is selected from any one or a combination of at least two of pentanediamine, hexanediamine, butanediamine, decanediamine, or dodecanediamine.

8. The alcoholysis-resistant polyamide resin according to claim 1 characterized in that the molar concentration of terminal amino groups in the polyamide resin is 64-140mmol/kg.

9. The alcoholysis-resistant polyamide resin according to claim 1 characterized in that the molar ratio of terminal amino groups to terminal carboxyl groups in the polyamide resin is 4:1-10:1.

10. The alcoholysis-resistant polyamide resin according to claim 1 wherein the comonomer further comprises an aromatic amide monomer.

11. The alcoholysis-resistant polyamide resin according to claim 10 characterized in that the aromatic amide monomer is selected from any one or a combination of at least two of nylon 6I salt, nylon 6T salt or nylon MXD6 salt.

12. The alcoholysis-resistant polyamide resin according to claim 10 characterized in that the aromatic amide monomer accounts for 3-5% of the comonomer by mass.

13. The alcoholysis-resistant polyamide resin according to claim 1 characterized in that the alcoholysis-resistant agent is selected from any one or a combination of at least two of bis (2, 6-diisopropylphenyl) carbodiimide, macromolecular hindered amine and phosphate compound, epoxy polymer hydrolysis-resistant agent or polycarbodiimide.

14. The alcoholysis-resistant polyamide resin according to claim 1 characterized in that the polyamide resin has a relative viscosity of 2.4-3.1.

15. The alcoholysis-resistant polyamide resin according to claim 14 characterized in that the polyamide resin has a relative viscosity of 2.55-2.65.

16. A process for the preparation of an alcoholysis-resistant polyamide resin according to any of claims 1-15 comprising the steps of:

(2) And (3) mixing the polyamide polymer obtained in the step (1) with an alcoholysis-resistant agent, and then carrying out slicing and granulating to obtain the alcoholysis-resistant polyamide resin.

17. The method of preparation of claim 16, wherein the comonomer is a concentrated comonomer solution.

18. The method of claim 17, wherein the solvent of the comonomer solution is desalted water.

19. The method of claim 17, wherein the concentration is performed in a concentration tank.

20. The method according to claim 19, wherein the pressure of the concentration tank is 0.2 to 0.3MPa.

21. The method of claim 17, wherein the concentrated comonomer solution has a mass concentration of 75 to 85%.

22. The method of claim 16, wherein the capping agent is a capping agent solution.

23. The method of claim 22, wherein the solvent of the capping agent solution is desalted water.

24. The method of claim 22, wherein the capping agent solution has a mass concentration of 45-55%.

25. The process of claim 16, wherein the temperature of the reaction in step (1) is 250 to 270 ℃.

26. The method of claim 16, wherein the reaction in step (1) comprises the stages of elevated temperature and pressure, maintaining pressure and elevated temperature, pressure relief and vacuum.

27. The method according to claim 26, wherein the rate of temperature rise in the temperature rise and pressure rise is 1.5 to 2 ℃/min.

28. The method of claim 26, wherein the elevated temperature and pressure are maintained for 15-25 minutes.

29. The method according to claim 26, wherein the pressure of the elevated temperature and pressure is 1.6 to 1.85MPa.

30. The method of claim 26, wherein the dwell pressure is 1.6-1.85MPa.

31. The method of claim 26, wherein the dwell time is 60-75 minutes.

32. The method according to claim 26, wherein the temperature of the pressure maintaining and the temperature increasing are 250 to 270 ℃.

33. The method of claim 26, wherein the pressure relief comprises a first pressure relief stage, a second pressure relief stage, and a third pressure relief stage.

34. The process of claim 33, wherein the pressure of the reaction after the first pressure relief stage is from 0.4MPa to 0.5MPa, the pressure of the reaction after the second pressure relief stage is from 0.15MPa to 0.25MPa, and the pressure of the reaction after the third pressure relief stage is from 0.095MPa to 0.15MPa.

35. The method of claim 26, wherein the pressure relief rate is 0.01-0.05MPa/min.

36. The method according to claim 26, wherein the vacuum degree of the reaction is-0.035 to-0.025 MPa after the evacuation stage.

37. The method of claim 36, wherein the vacuum is maintained for a period of 7-12 minutes.

38. The method of claim 16, wherein the reaction is carried out in the presence of nitrogen.

39. The method of claim 38, wherein in step (2), the mixing is performed by mixing with a mixer.

40. The method of claim 39, wherein the mixer is a feed mixer and a static mixer.

41. The preparation method according to claim 16, characterized in that the preparation method comprises the steps of:

(2) And (3) mixing the polyamide polymer obtained in the step (1) with an alcoholysis-resistant agent through a feeding mixer and a static mixer, and then performing slicing and granulation to obtain the alcoholysis-resistant polyamide resin.

42. Use of an alcoholysis-resistant polyamide resin according to any of claims 1-15 as a vehicle material.