CN110628211B

CN110628211B - Spraying-free polyamide 66/6 material and preparation method thereof

Info

Publication number: CN110628211B
Application number: CN201910995489.3A
Authority: CN
Inventors: 王忠强; 王礼军; 卢健体
Original assignee: Guangdong Aldex New Material Co Ltd
Current assignee: Guangdong Aldex New Material Co Ltd
Priority date: 2019-10-18
Filing date: 2019-10-18
Publication date: 2022-03-25
Anticipated expiration: 2039-10-18
Also published as: CN110628211A

Abstract

The invention relates to a spraying-free polyamide 66/6 material and a preparation method thereof, wherein the spraying-free polyamide 66/6 material is prepared by in-situ polymerization of the following raw materials: hexamethylene diamine, adipic acid, caprolactam, modified montmorillonite, modified pearlescent pigment, modified metal powder, benzoic acid, toluene diisocyanate and an antioxidant. The spraying-free polyamide 66/6 material has excellent mechanical property, processability and spraying-free effect, and can be applied to household appliance parts, automobile interior and exterior trimming parts and the like.

Description

Spraying-free polyamide 66/6 material and preparation method thereof

Technical Field

The invention relates to the field of materials, in particular to a spraying-free polyamide 66/6 material and a preparation method thereof.

Background

The traditional plastic part can obtain rich appearance effects including pearl effect, metal texture and flickering effect after being sprayed, and is favored by consumers, the appearance effects are applied to industries such as electronics, electric tools, household appliances, buildings, automobiles and the like, the unprecedented market competitiveness is displayed, but the spraying process is complicated and pollutes the environment, toxic and harmful gas and dust are generated, and the human health is harmed. In order to solve the problems of environmental pollution and energy waste generated in the spraying process, people continuously improve the spraying process flow, so that the spraying process flow gradually develops towards the direction of low organic solvent rate, aqueous solvent and powder pigment. In the field of resin application, the concept of a spraying-free product is developed, namely, metallic pigment, pearlescent pigment and other pigments with special color effects are directly added into a resin substrate, so that a series of products similar to the appearance effect of the spraying process treatment are obtained.

Polyamide, also known as nylon, is a polymer resin with a plurality of repeated polyamide groups on a molecular main chain, has good mechanical properties, heat resistance, wear resistance and chemical resistance, is easy to process, and is an ideal material for preparing household appliance parts and automobile interior and exterior trim parts.

Currently, some studies have been made in the prior art on spray-free polyamide materials, such as: chinese patent CN107674413A discloses a spraying-free polyamide resin compound and a preparation method thereof, wherein the polyamide resin compound comprises the following components in parts by weight: 30-70 parts of polyamide, 5-60 parts of AS-based polymer, 0.1-6 parts of effect pigment, 2-10 parts of compatilizer and 0-60 parts of filler; chinese patent CN107793754A discloses an environment-friendly low-odor spray-free polyamide composition, which comprises the following components in parts by weight: 95-100 parts of polyamide, 0.01-5 parts of metal compound and 0.1-6 parts of effect pigment; chinese patent CN107722620A discloses a low-odor high-gloss spray-free polyamide composition, which comprises the following components in parts by weight: 30-100 parts of polyamide, 0.1-6 parts of effect pigment, 0-50 parts of mineral filler, 0-20 parts of toughening agent, 0-5 parts of auxiliary agent, 0-1 part of heat stabilizer and 0-1 part of antioxidant; chinese patent CN108559258A discloses a high-flow spraying-free metallic silver polyamide composition and a preparation method thereof, wherein the raw materials comprise PA6 resin, metallic silver powder, a coupling agent, an internal lubricant, an external lubricant, an antioxidant, an ultraviolet absorbent, amino silicone oil, a flame retardant, calcium stearate, MBS, SMA, silicon dioxide, magnesium salt whisker, hollow glass bead, EBS, glass fiber, a compatilizer and ABS; chinese patent CN108976783A discloses a polyamide aesthetic resin composition with high metal texture, which is composed of the following components: 70-95 parts of Polyamide (PA), 0-5 parts of an auxiliary agent and 5.6-50 parts of special effect master batch; the special effect master batch consists of the following components: 5-30 parts of polymethyl methacrylate grafted maleic anhydride/styrene (PMMA-g-MAH/St), 0.5-18 parts of special effect toner and 0.1-2 parts of additive; chinese patent CN109897368A discloses a spraying-free heat-conducting nylon material for LED lighting products and a preparation method thereof, relating to the field of high polymer materials, wherein the spraying-free heat-conducting nylon material for LED lighting products comprises the following raw materials in parts by weight: 40-60 parts of polyamide, 5-10 parts of toughening agent, 30-50 parts of heat-conducting powder, 1-8 parts of metal pigment, 0.5-1.0 part of coupling agent, 0.2-0.6 part of antistatic agent and 0.2-0.6 part of antioxidant; chinese patent CN107216649A discloses a spraying-free polyamide composition with metallic luster, which comprises the following raw material components in parts by weight: 100 parts of polyamide resin, 4-20 parts of acrylonitrile-styrene copolymer, 0.2-2 parts of metal pigment, 2-10 parts of compatilizer, 0-25 parts of filler, 0.2-6 parts of toughening agent, 0.2-2 parts of dispersing aid and 0.2-2 parts of processing aid; chinese patent CN108299820A discloses a spraying-free nano nylon 6 composite material, which comprises the following raw materials in parts by weight: 70-94 parts of nano nylon 6 material, 4-10 parts of metal color master batch, 1-10 parts of antistatic agent and 1-10 parts of antibacterial agent; the nano nylon 6 material comprises the following raw materials in parts by mass: 81-87 parts of caprolactam and 3-6 parts of montmorillonite; chinese patent CN107805385A discloses a spraying-free nylon material and a preparation method thereof, wherein the spraying-free nylon material comprises the following raw materials by weight: 40-50 parts of nylon, 20-30 parts of reinforcement, 4-8 parts of foaming agent master batch, 2-4 parts of metal pigment master batch, 0.3-2.4 parts of lubricant and 1-4 parts of antioxidant; chinese patent CN109825077A discloses a heat-resistant spray-free high-gloss nylon material, which is composed of the following raw materials in parts by weight: 55.9-82.8 parts of semi-aromatic nylon resin, 5-20 parts of polycaprolactam and/or poly hexamethylene diamine, 10-20 parts of solid glass beads, 1-3 parts of brightening agent, 0.4-0.8 part of antioxidant, 0.5-1.5 parts of colorant and 0.3-0.8 part of lubricant; chinese patent CN108117745A discloses a spray-free toughened nylon 6 material and a preparation method thereof, belonging to the technical field of modification of high polymer materials, the material is composed of 59.4-76.9% of nylon 6 resin, 10-15% of toughening agent, 7-12% of plasticizer, 3-6% of maleic anhydride grafted polypropylene, 0.2-0.6% of oxidized polyethylene wax, 0.2-0.5% of flow modifier, 0.2-0.5% of antioxidant, 0.5-1.0% of lubricant and 2-5% of metal master batch.

It can be seen that the spraying-free polyamide materials disclosed in the prior art are a series of products similar to the appearance effect of the spraying process treatment by directly adding effect pigments with special colors, such as metal pigments, pearlescent pigments and the like, into a resin substrate, and the effect pigments directly added in the methods belong to inorganic components, and have poor compatibility with polyamide, so that the spraying-free polyamide materials are easy to have the problems of flow marks, welding marks and the like in the processing process, and the mechanical properties, such as tensile strength and the like, of the polyamide materials are influenced.

Disclosure of Invention

Based on the above, the invention aims to provide a polyamide 66 material which has excellent mechanical properties, processability and a spraying-free effect, has low probability of occurrence of problems such as flow marks, welding marks and the like in a processing process, and can be applied to household appliance parts, automobile interior and exterior parts and the like.

In order to achieve the purpose, the invention adopts the following scheme:

the spraying-free polyamide 66/6 material is prepared from the following raw materials in parts by weight:

the modified montmorillonite is obtained by reacting sodium-based montmorillonite with caprolactam;

the modified pearlescent pigment is obtained by reacting pearlescent pigment, succinic anhydride and gamma-aminopropyltriethoxysilane; the pearlescent pigment is one or a mixture of more than two of natural fish scale pearlescent pigment, bismuth oxychloride crystalline pearlescent pigment, mica coated pearlescent pigment, silicon dioxide coated pearlescent pigment, aluminum silicate coated pearlescent pigment, aluminum borate coated pearlescent pigment, artificial mica coated pearlescent pigment and bismuth oxide coated pearlescent pigment;

the modified metal powder is obtained by reacting metal powder, succinic anhydride and gamma-aminopropyltriethoxysilane; the metal powder is one or a mixture of more than two of aluminum powder, copper powder, silver powder, zinc powder and gold powder.

In some embodiments, the spraying-free polyamide 66/6 material is prepared from the following raw materials in parts by weight:

in some embodiments, the spraying-free polyamide 66/6 material is further preferably prepared from the following raw materials in parts by weight:

in some embodiments, the modified montmorillonite is obtained by reacting sodium montmorillonite and caprolactam in a mass ratio of 1: 0.03-0.05.

In some embodiments, the modified pearlescent pigment is obtained by reacting pearlescent pigment, succinic anhydride and gamma-aminopropyltriethoxysilane at a mass ratio of 1: 0.15-0.25: 0.4-0.5, and the molar numbers of the succinic anhydride and the gamma-aminopropyltriethoxysilane are equal.

In some embodiments, the modified metal powder is obtained by reacting metal powder, succinic anhydride and gamma-aminopropyltriethoxysilane at a mass ratio of 1: 0.15-0.25: 0.4-0.5, and the molar numbers of the succinic anhydride and the gamma-aminopropyltriethoxysilane are equal.

In some of these embodiments, the antioxidant consists of a primary antioxidant and a secondary antioxidant; the main antioxidant is one or a mixture of more than two of tetra (beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid) pentaerythritol ester, N '-1, 6-hexamethylene-bis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionamide ], N' -bis (2,2,6, 6-tetramethyl-4-piperidyl) -1, 3-benzenedicarboxamide; the auxiliary antioxidant is one or a mixture of more than two of tris (2, 4-di-tert-butylphenyl) phosphite, bis (2, 4-di-tert-butylphenol) pentaerythritol diphosphite, bis (2, 4-di-tert-butyl) pentaerythritol diphosphite and bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite.

In some of these embodiments, the primary antioxidant is N, N' -bis (2,2,6, 6-tetramethyl-4-piperidinyl) -1, 3-benzenedicarboxamide and the secondary antioxidant is bis (2, 6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphate.

In some of these embodiments, the pearlescent pigment is a silica-coated pearlescent pigment.

In some of these embodiments, the metal powder is aluminum powder.

In some of these embodiments, the pearlescent pigment has a particle size of 5 μm to 300 μm.

In some of these embodiments, the pearlescent pigment has a particle size of 10 to 30 μm.

In some of these embodiments, the metal powder has a particle size of 5 μm to 300 μm.

In some of these embodiments, the metal powder has a particle size of 10 μm to 30 μm.

In some of the embodiments, the spray-free polyamide 66/6 material has an intrinsic viscosity of 1.2-1.8 dL/g and a melting temperature of 240-253 ℃.

In some embodiments, the preparation method of the modified montmorillonite comprises the following steps: dispersing the sodium montmorillonite in distilled water at 75-85 ℃ to obtain montmorillonite water suspension, dissolving caprolactam and concentrated hydrochloric acid in distilled water at 55-65 ℃ to obtain caprolactam solution, pouring the caprolactam solution into the montmorillonite water suspension, stirring at 85-95 ℃ for 3-5 hours, and performing suction filtration to obtain the modified montmorillonite.

In some of these embodiments, the method of preparing the modified pearlescent pigment comprises the steps of: dispersing the succinic anhydride and the gamma-aminopropyltriethoxysilane in N, N-dimethylformamide, stirring for 2-4 hours at 55-65 ℃, adding N, N-dimethylformamide suspension of the pearlescent pigment subjected to ultrasonic dispersion into the system, simultaneously adding distilled water, stirring for 2-4 hours at 55-65 ℃, washing with ethanol, and performing centrifugal separation to obtain the modified pearlescent pigment.

In some embodiments, the method for preparing the modified metal powder comprises the following steps: dispersing the succinic anhydride and the gamma-aminopropyltriethoxysilane in N, N-dimethylformamide, stirring for 2-4 hours at 55-65 ℃, adding N, N-dimethylformamide suspension of ultrasonically dispersed metal powder into the system, simultaneously adding distilled water, stirring for 2-4 hours at 55-65 ℃, washing with ethanol, and performing centrifugal separation to obtain the modified metal powder.

In some embodiments, in the preparation of the modified montmorillonite, the mass ratio of the sodium montmorillonite to the caprolactam is 1: 0.03-0.05.

In some embodiments, the modified pearlescent pigment is prepared by mixing the pearlescent pigment, succinic anhydride and gamma-aminopropyltriethoxysilane in a mass ratio of 1: 0.15-0.25: 0.4-0.5, and the molar numbers of succinic anhydride and gamma-aminopropyltriethoxysilane are equal.

In some embodiments, in the preparation of the modified metal powder, the mass ratio of the metal powder to the succinic anhydride to the gamma-aminopropyltriethoxysilane is 1: 0.15-0.25: 0.4-0.5, and the molar numbers of the succinic anhydride and the gamma-aminopropyltriethoxysilane are equal.

The invention also aims to provide a preparation method of the spray-free polyamide 66/6 material.

The preparation method of the spraying-free polyamide 66/6 material comprises the following steps:

(1) adding the hexamethylene diamine and the adipic acid which are subjected to vacuum drying into a stirring type polymerization reactor, and simultaneously adding the caprolactam, the modified montmorillonite, the modified pearlescent pigment, the modified metal powder, the benzoic acid, the toluene diisocyanate, the antioxidant and a proper amount of water; vacuumizing for 3-7 min, introducing nitrogen for 3-7 min, and circulating for 4-8 times in such a way, so that reactants exist in an environment under the protection of nitrogen, and controlling the system pressure in the stirring type polymerization reactor to be 0.1-0.4 MPa;

(2) and (2) sealing the stirring type polymerization reactor within 2-4 hours, heating to 254-264 ℃ at a constant speed, adjusting the stirring speed of the stirring type polymerization reactor to 30-50 r/min, wherein when the temperature of the stirring type polymerization reactor reaches 200 ℃, gas is discharged to 1.1MPa, the pressure is maintained at 1.1MPa, after the reaction is carried out for 0.5-3 hours, the gas is discharged to normal pressure, meanwhile, the temperature is increased to 265-275 ℃, after the reaction is continued for 0.5-3 hours at 265-275 ℃, constant temperature continuous vacuum pumping is carried out for 0.1-2 hours, the reaction is finished, and nitrogen is supplemented during discharging, so that the spraying-free polyamide 66/6 material is obtained.

Introducing nitrogen before the reaction aims to reduce the probability of side reaction; adding a proper amount of water before the reaction has the functions of increasing the pressure in the kettle and transferring heat and mass in the heating process; the purpose of vacuumizing in the reaction process is to remove water generated in the polymerization reaction, so that the forward progress of the polymerization reaction is facilitated.

In some embodiments, the preparation method of the spray-free polyamide 66/6 material comprises the following steps:

(1) adding the hexamethylene diamine and the adipic acid which are subjected to vacuum drying into a stirring type polymerization reactor, and simultaneously adding the caprolactam, the modified montmorillonite, the modified pearlescent pigment, the modified metal powder, the benzoic acid, the toluene diisocyanate, the antioxidant and a proper amount of water; vacuumizing for 4-6 min, introducing nitrogen for 4-6 min, and circulating for 5-7 times in such a way, so that reactants exist in an environment under the protection of nitrogen, and controlling the system pressure in the stirring type polymerization reactor to be 0.2-0.3 MPa;

(2) heating the stirring type polymerization reactor to 256-262 ℃ in a sealed and uniform manner within 2-4 hours, adjusting the stirring speed of the stirring type polymerization reactor to 30-50 r/min, wherein when the temperature of the stirring type polymerization reactor reaches 200 ℃, gas is discharged to 1.1MPa, the pressure is maintained at 1.1MPa, after reacting for 1-2 hours, gas is discharged to normal pressure, meanwhile, the temperature is increased to 267-273 ℃, after continuing to react for 1-2 hours at 267-273 ℃, vacuum is continuously pumped at constant temperature for 0.3-1 hour, the reaction is finished, and nitrogen is supplemented during discharging, so that the spraying-free polyamide 66/6 material is obtained.

The principle of the spraying-free polyamide 66/6 material is as follows:

because the traditional spraying-free polyamide material uses inorganic components, the compatibility of the inorganic components and polyamide is poor, the problems of flow marks, welding marks and the like easily occur in the processing process of the spraying-free polyamide material, and the mechanical properties such as tensile strength and the like of the polyamide material can be influenced. In order to solve the problems, the invention takes hexamethylene diamine, adipic acid, caprolactam, modified montmorillonite, modified pearlescent pigment and modified metal powder as raw materials, and prepares the spraying-free polyamide material by in-situ polymerization, so that the compatibility between the obtained polyamide material and the modified montmorillonite, the modified pearlescent pigment and the modified metal powder can be improved, and the compatibility between the polyamide material and the modified montmorillonite, the modified pearlescent pigment and the modified metal powder is improved by adding a compatilizer toluene diisocyanate. After the sodium-based montmorillonite is organically modified by caprolactam, the interlayer spacing between montmorillonite layers can be effectively increased, the dispersion of montmorillonite in polyamide resin is facilitated, the crystallization rate of the polyamide resin is improved, the processing time is shortened, and the mechanical property and the flame retardant property of a polyamide material can be improved; after the pearlescent pigment and the metal powder are organically modified by succinic anhydride and gamma-aminopropyltriethoxysilane, carboxyl is carried on the particle surface of the pearlescent pigment and the metal powder, and the carboxyl can react with terminal amino of polyamide and isocyanate group of toluene diisocyanate, so that the compatibility between the pearlescent pigment and the metal powder and the polyamide is improved, and the probability of occurrence of problems such as flow marks, weld marks and the like in the processing process is reduced; the isocyanate group of the toluene diisocyanate can react with the terminal group of the polyamide, the terminal group of the modified montmorillonite, the terminal carboxyl group of the modified pearlescent pigment and the modified metal powder, so that the compatibility between the modified pearlescent pigment and the modified metal powder is improved. In addition, benzoic acid is added into the preparation raw materials of the spraying-free polyamide material, and the intrinsic viscosity of the polyamide material is adjusted by adopting the benzoic acid, so that the processing performance of the spraying-free polyamide material is improved.

The spraying-free polyamide 66/6 material and the preparation method thereof provided by the invention have the following advantages:

(1) the spraying-free polyamide 66/6 material disclosed by the invention has excellent mechanical properties, processability and spraying-free effect, has low probability of occurrence of problems such as flow marks, welding marks and the like in the processing process, and can be applied to household appliance parts, automobile interior and exterior trim parts and the like.

(2) The spraying-free polyamide 66/6 material is simple in preparation method, can be obtained by in-situ polymerization, and all reactions do not need to be carried out in a solvent, so that the subsequent complex process of removing the solvent is omitted.

(3) In the preparation method of the spray-free polyamide 66/6 material, low-molecular extractables generated in the polymerization process can be pumped away by high vacuum in the second preparation step, and the residual low-molecular extractables do not influence the performance of the spray-free polyamide 66/6 material, so that additional extraction equipment is not needed for separating the low-molecular extractables, and time and energy can be saved.

Drawings

FIG. 1 is a flow chart of a preparation process of a spraying-free polyamide 66/6 material.

Detailed Description

In order to further understand the features and technical means of the present invention and achieve the specific objects and functions, the advantages and spirit of the present invention are further illustrated by the following embodiments.

The reaction mechanism of the spraying-free polyamide 66/6 material of the invention is as follows (see the preparation process flow chart in figure 1):

wherein R is one of modified montmorillonite, modified pearlescent pigment and modified metal powder.

Mechanism of reaction

From the above reaction formula, the terminal groups of the polyamide and the modified montmorillonite, the terminal carboxyl groups of the modified pearlescent pigment and the modified metal powder can respectively react with the isocyanate group of the toluene diisocyanate, so as to improve the compatibility between the two.

The raw materials used in the embodiment of the invention are as follows:

hexamethylenediamine, available from Henan Shenma Nylon chemical, Inc.

Adipic acid, available from south Henan Shenma Nylon chemical Limited liability company.

Caprolactam available from Hubei Sanning chemical industries, Inc.

Sodium-based montmorillonite, available from Zhejiang Fenghong New materials, Inc.

Silica coated pearlescent pigments, particle size 20 μm, available from merck chemical technology (shanghai) ltd.

Aluminum powder, 20 μm in particle size, was purchased from merck chemical technology (shanghai) ltd.

Succinic anhydride, available from Puyang Puhui electronic materials, Inc.

Gamma-aminopropyltriethoxysilane, available from Shanghai Pont chemical Co., Ltd.

Benzoic acid, available from national pharmaceutical group chemical reagents, ltd.

Toluene diisocyanate, available from national pharmaceutical group chemical agents, ltd.

N, N' -bis (2,2,6, 6-tetramethyl-4-piperidinyl) -1, 3-benzenedicarboxamide, available from Toxongitai chemical Co., Ltd.

Bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate, available from Shanghai Yaozao Fine chemical Co., Ltd.

Polyamide 66/6, available from Shandong broad boundless novelty, Inc.

The preparation of the modified montmorillonite is as follows: dispersing 200g of sodium montmorillonite in 1000mL of distilled water at 80 ℃ to obtain montmorillonite aqueous suspension, dissolving 8g of caprolactam and 15mL of concentrated hydrochloric acid in 200mL of distilled water at 60 ℃ to obtain caprolactam solution, pouring the caprolactam solution into the montmorillonite aqueous suspension, stirring for 4 hours at 90 ℃, performing suction filtration to obtain modified montmorillonite, washing with distilled water, performing vacuum drying, crushing, and sieving with a 200-mesh sieve for later use.

The modified silica-coated pearlescent pigment was prepared as follows: 1mol of succinic anhydride (100g) and 1mol of gamma-aminopropyltriethoxysilane (221g) were dispersed in 1000mL of N, N-dimethylformamide, and after stirring at 60 ℃ for 3 hours, a suspension (3000mL) of ultrasonically dispersed silica-coated pearlescent pigment (500g) of N, N-dimethylformamide was added to the system, and simultaneously distilled water (500mL) was added thereto, and after stirring at 60 ℃ for 3 hours, the suspension was washed with ethanol several times and centrifuged to obtain a modified silica-coated pearlescent pigment.

The modified aluminum powder is prepared as follows: 1mol of succinic anhydride (100g) and 1mol of gamma-aminopropyltriethoxysilane (221g) were dispersed in 1000mL of N, N-dimethylformamide, and after stirring at 60 ℃ for 3 hours, a suspension (3000mL) of ultrasonically dispersed aluminum powder (500g) in N, N-dimethylformamide was added to the system, and simultaneously distilled water (500mL) was added thereto, and after stirring at 60 ℃ for 3 hours, the mixture was washed with ethanol several times and centrifuged to obtain a modified aluminum powder.

Example 1:

the spraying-free polyamide 66/6 material of the embodiment is prepared from the following raw materials in parts by weight:

(1) adding the hexamethylene diamine and adipic acid which are dried in vacuum into a stirring type polymerization reactor, and simultaneously adding the caprolactam, the modified montmorillonite, the modified silica-coated pearlescent pigment, the modified aluminum powder, the benzoic acid, the toluene diisocyanate, the N, N' -bis (2,2,6, 6-tetramethyl-4-piperidyl) -1, 3-benzenedicarboxamide, the bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate and 150 parts of water; then vacuumizing for 3min, introducing nitrogen for 3min, and circulating for 8 times in such a way, so that reactants exist in the environment under the protection of nitrogen, and controlling the system pressure in the stirring type polymerization reactor to be 0.1 MPa;

(2) and (2) sealing the stirring type polymerization reactor within 2 hours, heating to 264 ℃ at a constant speed, adjusting the stirring speed of the stirring type polymerization reactor to 40r/min, wherein when the temperature of the stirring type polymerization reactor reaches 200 ℃, gas is released to 1.1MPa, the pressure is maintained at 1.1MPa, after 0.5 hour of reaction, gas is released to normal pressure, the temperature is increased to 275 ℃, after 0.5 hour of continuous reaction at 275 ℃, constant temperature continuous vacuum pumping is carried out for 2 hours, the reaction is finished, and nitrogen is supplemented during discharging, so that the spraying-free polyamide 66/6 material is obtained.

Example 2:

(1) adding the hexamethylene diamine and adipic acid which are dried in vacuum into a stirring type polymerization reactor, and simultaneously adding the caprolactam, the modified montmorillonite, the modified silica-coated pearlescent pigment, the modified aluminum powder, the benzoic acid, the toluene diisocyanate, the N, N' -bis (2,2,6, 6-tetramethyl-4-piperidyl) -1, 3-benzenedicarboxamide, the bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate and 150 parts of water; vacuumizing for 7min, introducing nitrogen for 7min, and circulating for 4 times in such a way, so that reactants exist in the environment under the protection of nitrogen, and controlling the system pressure in the stirring type polymerization reactor to be 0.4 MPa;

(2) and (2) sealing the stirring type polymerization reactor within 4 hours, heating to 254 ℃ at a constant speed, adjusting the stirring speed of the stirring type polymerization reactor to 40r/min, wherein when the temperature of the stirring type polymerization reactor reaches 200 ℃, gas is released to 1.1MPa, the pressure is maintained at 1.1MPa, after 3 hours of reaction, gas is released to normal pressure, the temperature is simultaneously raised to 265 ℃, after 3 hours of continuous reaction at 265 ℃, constant temperature continuous vacuum pumping is carried out for 0.1 hour, after the reaction is finished, nitrogen is supplemented during discharging, and the spraying-free polyamide 66/6 material is obtained.

Example 3:

(1) adding the hexamethylene diamine and adipic acid which are dried in vacuum into a stirring type polymerization reactor, and simultaneously adding the caprolactam, the modified montmorillonite, the modified silica-coated pearlescent pigment, the modified aluminum powder, the benzoic acid, the toluene diisocyanate, the N, N' -bis (2,2,6, 6-tetramethyl-4-piperidyl) -1, 3-benzenedicarboxamide, the bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate and 150 parts of water; then vacuumizing for 4min, introducing nitrogen for 4min, and circulating for 7 times in such a way, so that reactants exist in the environment under the protection of nitrogen, and controlling the system pressure in the stirring type polymerization reactor to be 0.2 MPa;

(2) and (2) sealing the stirring type polymerization reactor within 2 hours, heating to 262 ℃ at a constant speed, adjusting the stirring speed of the stirring type polymerization reactor to 40r/min, wherein when the temperature of the stirring type polymerization reactor reaches 200 ℃, gas is released to 1.1MPa, the pressure is maintained at 1.1MPa, after the reaction is carried out for 1 hour, gas is released to normal pressure, the temperature is increased to 273 ℃, after the reaction is continued for 1 hour at 273 ℃, constant temperature continuous vacuum pumping is carried out for 1 hour, the reaction is finished, and nitrogen is supplemented during discharging, so that the spraying-free polyamide 66/6 material is obtained.

Example 4:

(1) adding the hexamethylene diamine and adipic acid which are dried in vacuum into a stirring type polymerization reactor, and simultaneously adding the caprolactam, the modified montmorillonite, the modified silica-coated pearlescent pigment, the modified aluminum powder, the benzoic acid, the toluene diisocyanate, the N, N' -bis (2,2,6, 6-tetramethyl-4-piperidyl) -1, 3-benzenedicarboxamide, the bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate and 150 parts of water; then vacuumizing for 6min, introducing nitrogen for 6min, and circulating for 5 times in such a way, so that reactants exist in the environment under the protection of nitrogen, and controlling the system pressure in the stirring type polymerization reactor to be 0.3 MPa;

(2) and (2) sealing the stirring type polymerization reactor within 4 hours, heating to 256 ℃ at a constant speed, adjusting the stirring speed of the stirring type polymerization reactor to be 30-50 r/min, wherein when the temperature of the stirring type polymerization reactor reaches 200 ℃, gas is discharged to 1.1MPa, the pressure is maintained at 1.1MPa, after 2 hours of reaction, gas is discharged to normal pressure, the temperature is increased to 267 ℃, after 2 hours of continuous reaction at 267 ℃, constant temperature continuous vacuum pumping is carried out for 0.3 hour, after the reaction is finished, nitrogen is supplemented during discharging, and the spraying-free polyamide 66/6 material is obtained.

Example 5:

(1) adding the hexamethylene diamine and adipic acid which are dried in vacuum into a stirring type polymerization reactor, and simultaneously adding the caprolactam, the modified montmorillonite, the modified silica-coated pearlescent pigment, the modified aluminum powder, the benzoic acid, the toluene diisocyanate, the N, N' -bis (2,2,6, 6-tetramethyl-4-piperidyl) -1, 3-benzenedicarboxamide, the bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate and 150 parts of water; then vacuumizing for 5min, introducing nitrogen for 5min, and circulating for 6 times in such a way, so that reactants exist in the environment under the protection of nitrogen, and controlling the system pressure in the stirring type polymerization reactor to be 0.25 MPa;

(2) and (2) heating the stirring type polymerization reactor to 259 ℃ in a sealed manner at a constant speed within 3 hours, adjusting the stirring speed of the stirring type polymerization reactor to 40r/min, wherein when the temperature of the stirring type polymerization reactor reaches 200 ℃, the gas is released to 1.1MPa, the pressure is maintained at 1.1MPa, after 1.5 hours of reaction, the gas is released to normal pressure, the temperature is increased to 270 ℃, after 1.5 hours of continuous reaction at 270 ℃, constant temperature continuous vacuum pumping is carried out for 0.5 hour, the reaction is finished, and nitrogen is supplemented during discharging, so that the spraying-free polyamide 66/6 material is obtained.

Example 6:

Example 7:

Comparative example 1:

(1) adding the hexamethylene diamine and adipic acid which are dried in vacuum into a stirring type polymerization reactor, and simultaneously adding the caprolactam, the modified montmorillonite, the modified silicon dioxide coated pearlescent pigment, the modified aluminum powder, the benzoic acid, the N, N' -bis (2,2,6, 6-tetramethyl-4-piperidyl) -1, 3-phthalic diamide, the bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate and 150 parts of water; then vacuumizing for 5min, introducing nitrogen for 5min, and circulating for 6 times in such a way, so that reactants exist in the environment under the protection of nitrogen, and controlling the system pressure in the stirring type polymerization reactor to be 0.25 MPa;

Comparative example 2:

(1) adding hexamethylene diamine and adipic acid which are dried in vacuum into a stirring type polymerization reactor, and simultaneously adding the caprolactam, the modified silicon dioxide coated pearlescent pigment, the modified aluminum powder, benzoic acid, toluene diisocyanate, N' -bis (2,2,6, 6-tetramethyl-4-piperidyl) -1, 3-benzenedicarboxamide, bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate and 150 parts of water; then vacuumizing for 5min, introducing nitrogen for 5min, and circulating for 6 times in such a way, so that reactants exist in the environment under the protection of nitrogen, and controlling the system pressure in the stirring type polymerization reactor to be 0.25 MPa;

Comparative example 3

(1) adding the hexamethylene diamine and adipic acid which are dried in vacuum into a stirring type polymerization reactor, and simultaneously adding the caprolactam, the sodium-based montmorillonite, the modified silica-coated pearlescent pigment, the modified aluminum powder, the benzoic acid, the toluene diisocyanate, the N, N' -bis (2,2,6, 6-tetramethyl-4-piperidyl) -1, 3-benzenedicarboxamide, the bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate and 150 parts of water; then vacuumizing for 5min, introducing nitrogen for 5min, and circulating for 6 times in such a way, so that reactants exist in the environment under the protection of nitrogen, and controlling the system pressure in the stirring type polymerization reactor to be 0.25 MPa;

Comparative example 4

(1) adding the hexamethylene diamine and adipic acid which are dried in vacuum into a stirring type polymerization reactor, and simultaneously adding the caprolactam, the modified montmorillonite, the silica-coated pearlescent pigment, the aluminum powder, the benzoic acid, the toluene diisocyanate, the N, N' -bis (2,2,6, 6-tetramethyl-4-piperidyl) -1, 3-benzenedicarboxamide, the bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate and 150 parts of water; then vacuumizing for 5min, introducing nitrogen for 5min, and circulating for 6 times in such a way, so that reactants exist in the environment under the protection of nitrogen, and controlling the system pressure in the stirring type polymerization reactor to be 0.25 MPa;

Comparative example 5

(1) adding the hexamethylene diamine and adipic acid which are dried in vacuum into a stirring type polymerization reactor, and simultaneously adding the caprolactam, the modified montmorillonite, the modified silicon dioxide coated pearlescent pigment, the modified aluminum powder, the toluene diisocyanate, the N, N' -bis (2,2,6, 6-tetramethyl-4-piperidyl) -1, 3-benzenedicarboxamide, the bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate and 150 parts of water; then vacuumizing for 5min, introducing nitrogen for 5min, and circulating for 6 times in such a way, so that reactants exist in the environment under the protection of nitrogen, and controlling the system pressure in the stirring type polymerization reactor to be 0.25 MPa;

Comparative example 6

(1) drying the polyamide 66/6 at 125 ℃ for 5 hours, cooling, and placing the cooled polyamide 66/6 for later use;

(2) adding the modified montmorillonite and the modified silicon dioxide coated pearlescent pigment, modified aluminum powder, benzoic acid, toluene diisocyanate, N' -bis (2,2,6, 6-tetramethyl-4-piperidyl) -1, 3-phthalic diamide and bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate into a high-speed stirrer (the rotating speed is 1000 revolutions per minute) for mixing;

(3) adding the polyamide 66/6 dried in the step (1) into a parallel double-screw extruder through a feeder, adding the mixture mixed in the step (2) into the parallel double-screw extruder (totally eight zones) in the lateral direction (fourth zone), performing melt extrusion, and granulating, wherein the process parameters are as follows: the temperature in the first zone was 250 ℃, the temperature in the second zone was 255 ℃, the temperature in the third zone was 260 ℃, the temperature in the fourth zone was 265 ℃, the temperature in the fifth zone was 270 ℃, the temperature in the sixth zone was 270 ℃, the temperature in the seventh zone was 265 ℃, the temperature in the eighth zone was 265 ℃, the temperature in the die head was 260 ℃ and the screw speed was 400 rpm.

The following is a summary of the raw material compositions of examples 1-7 and comparative examples 1-6.

TABLE 1 summary of the raw material compositions of examples 1-7 and comparative examples 1-6

Remarking: replacing the modified montmorillonite with montmorillonite; replacing the modified pearlescent pigment with the pearlescent pigment; c, replacing the modified metal powder with metal powder; d, hexamethylenediamine, adipic acid and caprolactam are replaced by polyamide 66/6.

Wherein the hexamethylenediamine and the adipic acid are 50 parts and 62.9 parts respectively in the examples and the comparative examples, and the N, N' -bis (2,2,6, 6-tetramethyl-4-piperidyl) -1, 3-benzenedicarboxamide (main antioxidant) and the bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate (auxiliary antioxidant) are 0.2 part respectively in the examples and the comparative examples.

The spray-free polyamide 66/6 materials prepared in the above examples and comparative examples were subjected to the following performance tests:

tensile property: the tensile rate is 50mm/min according to the test of GB/T1040-2006 standard.

Melt index: the test temperature is 275 ℃ and the load is 2.16kg according to the test of GB/T3682-2000-plus-2000 standard.

Flow mark and weld mark: respectively performing injection molding by using 100 mm-3 mm molds through an injection molding machine, and visually judging the surface effect, wherein I represents that the surface effect is excellent and no flow mark or fusion mark exists; II represents that the surface effect is between I and III; III indicates that the surface effect is moderate and slight flow marks or welding marks exist; IV is between III and V; v indicates that the surface effect is poor and that there are serious flow marks and weld marks.

Intrinsic viscosity: tested according to GB/T1632-2008 standard, the solvent is concentrated sulfuric acid.

Melting temperature: testing according to GB/T19466.3-2004 standard.

The results of the performance tests are shown in table 2.

TABLE 2 Properties of the spray-free Polyamide 66/6 materials of examples 1 to 7 and comparative examples 1 to 6

Examples 1 to 7 are to adjust the addition amounts of modified montmorillonite, benzoic acid and toluene diisocyanate, and it can be seen from the table that with the increase of the addition amounts of modified montmorillonite and toluene diisocyanate, the tensile strength of the polyamide 66/6 material shows a trend of increasing first and then decreasing, because a certain amount of modified montmorillonite can be used as a nucleating agent, the crystallization rate and the crystallinity of polyamide are increased, the processing time is shortened, and the tensile strength of polyamide is increased, and the terminal groups of polyamide and modified montmorillonite, the terminal carboxyl groups of modified pearlescent pigment and modified metal powder can respectively react with the isocyanate group of toluene diisocyanate, thereby improving the compatibility between them and reducing the influence on the mechanical properties, when the addition amount of toluene diisocyanate is increased to 0.6 part, the addition amount is increased again, the tensile strength is not changed much, and exhibits a decreasing trend; with the increase of the addition amount of benzoic acid and caprolactam, the intrinsic viscosity and the melting temperature of the polyamide 66/6 material are gradually reduced, the melt index is gradually increased, the processability is better, but when the intrinsic viscosity is too low, the mechanical property of the polyamide is influenced, and when the addition amount of benzoic acid is 0.3 part, the comprehensive performance is better; the polyamide 66/6 material of each example did not generate flow marks and weld marks; by comparison, the polyamide 66/6 material prepared in example 7 exhibited the best overall properties.

Compared with the comparative example 1, in the comparative example 1, toluene diisocyanate is not added, and the modified montmorillonite, the modified silica-coated pearlescent pigment and the modified aluminum powder are easy to have the phenomenon of poor partial compatibility in the in-situ polymerization process of hexamethylene diamine, adipic acid and caprolactam, so that the mechanical property of the prepared polyamide 66/6 material is influenced, and the injection molding defects such as flow marks, welding marks and the like are easy to occur; compared with the comparative example 2, the comparative example 2 does not add the modified montmorillonite, so the tensile strength of the polyamide 66/6 material prepared by the comparative example 2 is inferior to that of the example 7, and the poor injection molding phenomena such as flow marks, welding marks and the like are easy to occur in the processing process; compared with the comparative example 3, in the comparative example 3, the unmodified sodium-based montmorillonite is used, and in the in-situ polymerization process of hexamethylene diamine, adipic acid and caprolactam, the compatibility of the sodium-based montmorillonite and polyamide is poor, and the agglomeration phenomenon is easy to occur, so that the mechanical property of the prepared polyamide 66/6 material is influenced, and poor injection molding phenomena such as flow marks, welding marks and the like are easy to occur; example 7 compared with comparative example 4, comparative example 4 uses unmodified pearl pigment and metal powder, and the pearl pigment has poor compatibility with the metal powder and polyamide base resin, so that the prepared polyamide 66/6 material is easy to have poor injection molding phenomena such as flow marks, weld marks and the like in the processing process; compared with the comparative example 5, in the comparative example 5, no polymerization inhibitor benzoic acid is added, the prepared polyamide material has excessively high intrinsic viscosity, excessively low melt index and poor processability, and poor injection molding phenomena such as flow marks, welding marks and the like are easy to occur in the processing process; example 7 in comparison with comparative example 6, comparative example 6 prepared a spray-free polyamide 66/6 material by a common blending method using a polyamide 66/6 resin, which affects the compatibility between each raw material component and polyamide 66/6, thus resulting in lower tensile properties than example 7, and is prone to poor injection molding phenomena such as flow marks, weld marks and the like during processing.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. The spraying-free polyamide 66/6 material is characterized by being prepared from the following raw materials in parts by weight:

50 parts of hexamethylene diamine, namely, hexamethylene diamine,

62.9 parts of adipic acid, namely,

5-15 parts of caprolactam,

1-10 parts of modified montmorillonite,

0.1 to 3 parts of modified pearlescent pigment,

0.1 to 3 parts of modified metal powder,

0.01 to 1 part of benzoic acid,

0.1 to 2 parts of toluene diisocyanate,

0.1-0.6 part of antioxidant;

the modified montmorillonite is obtained by reacting sodium montmorillonite and caprolactam in a mass ratio of 1: 0.03-0.05;

the modified pearlescent pigment is obtained by reacting pearlescent pigment, succinic anhydride and gamma-aminopropyltriethoxysilane in a mass ratio of 1: 0.15-0.25: 0.4-0.5, and the molar numbers of the succinic anhydride and the gamma-aminopropyltriethoxysilane are equal; the pearlescent pigment is one or a mixture of more than two of natural fish scale pearlescent pigment, bismuth oxychloride crystalline pearlescent pigment, mica coated pearlescent pigment, silicon dioxide coated pearlescent pigment, aluminum silicate coated pearlescent pigment, aluminum borate coated pearlescent pigment and bismuth oxide coated pearlescent pigment;

the modified metal powder is obtained by reacting metal powder, succinic anhydride and gamma-aminopropyltriethoxysilane according to the mass ratio of 1: 0.15-0.25: 0.4-0.5, and the molar numbers of the succinic anhydride and the gamma-aminopropyltriethoxysilane are equal; the metal powder is one or a mixture of more than two of aluminum powder, copper powder, silver powder, zinc powder and gold powder;

the preparation method of the modified montmorillonite comprises the following steps: dispersing the sodium montmorillonite in distilled water at the temperature of 75-85 ℃ to obtain montmorillonite water suspension, dissolving caprolactam and concentrated hydrochloric acid in distilled water at the temperature of 55-65 ℃ to obtain caprolactam solution, pouring the caprolactam solution into the montmorillonite water suspension, stirring at the temperature of 85-95 ℃ for 3-5 hours, and performing suction filtration to obtain the modified montmorillonite;

the preparation method of the modified pearlescent pigment comprises the following steps: dispersing the succinic anhydride and the gamma-aminopropyltriethoxysilane in N, N-dimethylformamide, stirring for 2-4 hours at 55-65 ℃, adding N, N-dimethylformamide suspension of pearlescent pigment subjected to ultrasonic dispersion into the system, simultaneously adding distilled water, stirring for 2-4 hours at 55-65 ℃, washing with ethanol, and performing centrifugal separation to obtain the modified pearlescent pigment;

the preparation method of the modified metal powder comprises the following steps: dispersing the succinic anhydride and the gamma-aminopropyltriethoxysilane in N, N-dimethylformamide, stirring for 2-4 hours at 55-65 ℃, adding N, N-dimethylformamide suspension of ultrasonically dispersed metal powder into the system, simultaneously adding distilled water, stirring for 2-4 hours at 55-65 ℃, washing with ethanol, and performing centrifugal separation to obtain the modified metal powder;

the preparation method of the spray-free polyamide 66/6 material comprises the following steps:

2. The spray-free polyamide 66/6 material of claim 1, wherein the spray-free polyamide 66/6 material is prepared from the following raw materials in parts by weight:

50 parts of hexamethylene diamine, namely, hexamethylene diamine,

62.9 parts of adipic acid, namely,

9-15 parts of caprolactam,

3-10 parts of modified montmorillonite,

0.3 to 3 parts of modified pearlescent pigment,

0.3 to 3 parts of modified metal powder,

0.1 to 1 part of benzoic acid,

0.3 to 2 parts of toluene diisocyanate,

0.15-0.5 part of antioxidant.

3. The spray-free polyamide 66/6 material of claim 1 or 2, wherein the spray-free polyamide 66/6 material is prepared from the following raw materials in parts by weight:

50 parts of hexamethylene diamine, namely, hexamethylene diamine,

62.9 parts of adipic acid, namely,

9-11 parts of caprolactam,

4-7 parts of modified montmorillonite,

0.5 to 1 portion of modified pearlescent pigment,

0.5 to 1 part of modified metal powder,

0.2 to 0.6 part of benzoic acid,

0.5 to 1 part of toluene diisocyanate,

0.18-0.44 parts of antioxidant.

4. The spray-free polyamide 66/6 material of claim 1 or 2, wherein the antioxidant consists of a primary antioxidant and a secondary antioxidant; the main antioxidant is one or a mixture of more than two of tetra (beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid) pentaerythritol ester, N '-1, 6-hexamethylene-bis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionamide ], N' -bis (2,2,6, 6-tetramethyl-4-piperidyl) -1, 3-benzenedicarboxamide; the auxiliary antioxidant is one or a mixture of more than two of tris (2, 4-di-tert-butylphenyl) phosphite, bis (2, 4-di-tert-butylphenyl) pentaerythritol diphosphite and bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite.

5. The spray-free polyamide 66/6 material according to claim 1 or 2, wherein the pearlescent pigment is a silica-coated pearlescent pigment; and/or the presence of a catalyst in the reaction mixture,

the metal powder is aluminum powder; and/or the presence of a catalyst in the reaction mixture,

the antioxidant comprises a main antioxidant and an auxiliary antioxidant, wherein the main antioxidant is N, N' -bis (2,2,6, 6-tetramethyl-4-piperidyl) -1, 3-benzenedicarboxamide, and the auxiliary antioxidant is bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate.

6. The spray-free polyamide 66/6 material according to claim 1 or 2, wherein the pearlescent pigment has a particle size of 5 to 300 μm; and/or the presence of a catalyst in the reaction mixture,

the particle size of the metal powder is 5-300 mu m; and/or the presence of a catalyst in the reaction mixture,

the spray-free polyamide 66/6 material has an intrinsic viscosity of 1.2-1.8 dL/g and a melting temperature of 240-253 ℃.

7. The spray-free polyamide 66/6 material of claim 6, wherein the pearlescent pigment has a particle size of 10-30 μm.

8. The spray-free polyamide 66/6 material of claim 6, wherein the metal powder has a particle size of 10-30 μm.

9. A method for preparing the spray-free polyamide 66/6 material according to any one of claims 1-8, comprising the steps of:

10. The method of claim 9, comprising the steps of: