An ultraviolet resistant / salt fog resistant polyamide composite and a method of making the same

Abstract

The application discloses an anti-ultraviolet / salt fog resistant polyamide composite and a preparation method thereof, and relates to the field of engineering plastic processing. The anti-ultraviolet / salt fog resistant polyamide composite comprises the following components in mass fractions: 70-94 parts of polyamide resin, 5-20 parts of anti-ultraviolet polyamide master batch and 1-10 parts of polydopamine modified hydrotalcite nano particles. The anti-ultraviolet polyamide master batch comprises the following components in mass fractions: 55-99 parts of polyhexamethylene adipamide salt solution with a mass concentration of 5-50 %, 1-50 parts of modified anti-ultraviolet agent salt and 0.3-1.5 parts of antioxidant. The modified anti-ultraviolet agent salt is obtained by reacting 5-50 parts of amino-terminated modified anti-ultraviolet agent compound and 5-50 parts of dicarboxylic acid in anhydrous ethanol. The polydopamine modified hydrotalcite nano particles comprise layered hydrotalcite nano particles and a polydopamine coating layer on the surface of the hydrotalcite nano particles. The anti-ultraviolet / salt fog resistant polyamide composite has persistent and stable anti-ultraviolet performance and salt fog resistance, and meanwhile, the mechanical properties of the polyamide material itself can be maintained, so that the anti-ultraviolet / salt fog resistant polyamide composite has high application value.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat-conducting materials, in particular to an ultraviolet-resistant / salt-mist-resistant polyamide composite material and a preparation method thereof. BACKGROUND

[0002] Polyamide (nylon) materials have good comprehensive properties, including mechanical properties, heat resistance, wear resistance, chemical resistance, self-lubricating, and easy processing characteristics, and are widely used in the fields of national defense, machinery, chemical industry, etc. However, polyamide materials will age under sunlight, ultraviolet rays or high-energy radiation, and defects such as yellowing, brittleness, cracking, loss of surface gloss, and degradation of mechanical and electrical properties will occur, so that the materials eventually lose their value. In addition, there are a large number of polar amide groups in polyamide, and water molecules and salt substances are easy to penetrate into the resin matrix under high humidity and salt mist environment, causing the resin matrix to swell, plasticize, and corrode, resulting in changes such as decrease in mechanical properties, decrease in dimensional stability, surface damage, and molecular degradation, which makes the material fail and reduces the service life.

[0003] Adding ultraviolet absorbers to polyamide material products is currently the main method to delay ultraviolet aging and prolong service life. For example, patent 202410307632.6 uses cashew phenol to modify rare earth oxides with good ultraviolet resistance, and uses the complexation of the phenolic hydroxyl group with rare earth elements to graft long carbon chain groups on the surface of the rare earth oxide, improving the dispersibility of the rare earth oxide and its compatibility with the nylon matrix, and preparing a nylon material with good ultraviolet resistance; patent 202011431131.7 introduces ultraviolet-resistant nano-titanium dioxide during the polymerization of caprolactam to prepare an ultraviolet-resistant nylon master batch, which is further compounded with special nylon materials to obtain an ultraviolet-resistant biaxially stretched nylon film. However, due to the small particle size and large specific surface area of the ultraviolet-resistant agent particles, the interface between the ultraviolet-resistant agent particles and the polyamide matrix is not stable enough, and the agglomerated ultraviolet-resistant agent particles can also degrade the performance of the polyamide. Therefore, it is urgent to find a substance or method that can more stably and uniformly combine the ultraviolet-resistant agent with the polyamide matrix. SUMMARY

[0004] In order to solve the problems existing in the prior art, the purpose of the present application is to provide an ultraviolet-resistant / salt-mist-resistant polyamide composite material and a preparation method thereof. The ultraviolet-resistant / salt-mist-resistant polyamide composite material of the present application has persistent and stable ultraviolet resistance and salt mist resistance, and has high application value.

[0005] The present application provides the following technical solutions:

[0006] The application provides an anti-ultraviolet / salt mist resistant polyamide composite material, which comprises the following components in mass fractions: 70-94 parts of a polyamide resin, 5-20 parts of an anti-ultraviolet polyamide master batch and 1-10 parts of polydopamine modified hydrotalcite nanoparticles.

[0007] The anti-ultraviolet polyamide master batch comprises the following components in mass fractions: 55-99 parts of a polyhexamethylene adipamide salt solution with a mass concentration of 5-50%, 1-50 parts of a modified anti-ultraviolet agent salt and 0.3-1.5 parts of an antioxidant; the modified anti-ultraviolet agent salt is obtained by reacting 5-50 parts of an amino-terminated modified anti-ultraviolet agent compound and 5-50 parts of a dicarboxylic acid in anhydrous ethanol;

[0008] The polydopamine modified hydrotalcite nanoparticles comprise layered hydrotalcite nanoparticles and a polydopamine coating layer on the surface of the nanoparticles.

[0009] Further, the modified anti-ultraviolet agent salt is obtained by dissolving the amino-terminated modified anti-ultraviolet agent compound and the dicarboxylic acid in anhydrous ethanol, then reacting at 50-80 DEG C in a water bath for 1-3 h, and finally filtering, washing and purifying.

[0010] Further, the amino-terminated modified anti-ultraviolet agent compound comprises the following components in mass fractions: 5-40 parts of an anti-ultraviolet agent A, 2-80 parts of a multifunctional isocyanate compound, 10-70 parts of a modifier, 5-10 parts of an anti-ultraviolet agent B, 1-50 parts of a diamine, 60-100 parts of acetone and 0.01-5 parts of a catalyst.

[0011] Further, the amino-terminated modified anti-ultraviolet agent compound is prepared by the following method: uniformly dispersing the anti-ultraviolet agent A, the multifunctional isocyanate compound and the catalyst in a solvent, heating to 40-70 DEG C under a protective atmosphere and reacting for 2-3 h; then adding the modifier and the anti-ultraviolet agent B and reacting at 70-90 DEG C for 2-3 h; finally adding the diamine and continuing to react at 60-100 DEG C for 0.5-1 h to obtain the amino-terminated modified anti-ultraviolet agent compound.

[0012] Preferably, the anti-ultraviolet agent A is at least one selected from 4,4'-dihydroxybenzophenone, 2,4-dihydroxybenzophenone, 3,4-dihydroxybenzophenone, 2,2'-dihydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2,2'-hydroxy-4-methoxybenzophenone and ethylene glycol salicylate.

[0013] Preferably, the anti-ultraviolet agent B is at least one selected from PEG functionalized nano-silicon dioxide, propylene glycol nano-titanium dioxide, aminated titanium dioxide nanoparticles, aminated silicon dioxide nanoparticles and aminated zinc oxide nanoparticles.

[0014] Preferably, the diamine is selected from at least one of ethylenediamine, propylenediamine, hexylenediamine, 1,4-butylenediamine, 1,5-pentylenediamine, 1,6-hexylenediamine.

[0015] Preferably, the modifier is selected from at least one of polyethylene glycol, polypropylene glycol, 2,2-dimethylol butyric acid, 2,2-dimethylol propionic acid, 3,5-dihydroxy-3-methyl pentanoic acid, 4,5-dihydroxy-2-(hydroxymethyl) pentanoic acid.

[0016] Preferably, the polyethylene glycol has a molecular weight of 400-8000 g / mol; the polypropylene glycol has a molecular weight of 400-2000 g / mol.

[0017] Preferably, the molar ratio of the polyfunctional isocyanate compound, the anti-UV agent A, the modifier, and the diamine is (2.5-3) : 1 : 1 : (0.6-1.2).

[0018] Further, by compounding the anti-UV agent A, the polyfunctional isocyanate compound, the anti-UV agent B, and the diamine, the hydroxyl group of the anti-UV agent A, the amino group of the anti-UV agent B, and the diamine can react with the polyfunctional isocyanate compound, so as to obtain an amino-terminated modified anti-UV agent by modifying the molecular structure.

[0019] Preferably, the solvent is selected from any one of acetone, diethyl ether, glacial acetic acid, methanol, isopropyl alcohol, ethyl acetate.

[0020] Preferably, the catalyst is selected from any one of dibutyl tin, tributyl tin, cyclohexyl tributyl tin, triethylenediamine, dibutyl tin dilaurate, dibutyl tin diacetate, triethanolamine, dimethyl amino imidazole.

[0021] Preferably, the dicarboxylic acid is selected from at least one of oxalic acid, adipic acid, azelaic acid, sebacic acid, terephthalic acid, isophthalic acid.

[0022] Preferably, the molar ratio of the amino-terminated modified anti-UV agent compound and the dicarboxylic acid is 1:1.

[0023] Preferably, the antioxidant is selected from at least one of 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-(dimethylaminomethyl)phenol, 4,4'-methylenebis(2,6-di-tert-butylphenol), tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]pentaerythritol ester, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, tris[2,4-di-tert-butylphenyl] phosphite, n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, triethylene glycol bis-3-(3-tert-butyl-4-hydroxy-5-methylbenzyl)propionate.

[0024] Preferably, the polyfunctional isocyanate compound is selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, lysine diisocyanate.

[0025] Further, the polydopamine modified hydrotalcite nanoparticles are obtained by reacting 5-20 parts by mass of hydrochloric acid dopamine and 1-10 parts of layered hydrotalcite nanoparticles in a buffer solution with a pH of 8.3-8.7; the buffer solution is a 2-20% by mass trimethylolamine solution. Preferably, the reaction is specifically stirring at 30-50℃ for 5-8h.

[0026] Further, the polyamide resin is selected from one of poly-caprolactam (PA6) resin, poly-decanolactam (PA10) resin, poly-undecanolactam (PA11) resin, poly-dodecanolactam (PA12) resin, poly-butylene adipamide (PA46) resin, poly-pentamethylene adipamide (PA56) resin, PA66 (poly-hexamethylene adipamide) resin, poly-hexamethylene sebacamide (PA610) resin, poly-hexamethylene dodecanamide (PA612) resin, poly-hexamethylene decanamide (PA1010) resin, poly-hexamethylene dodecanamide (PA1012) resin, poly-dodecanamide dodecanamide (PA1212) resin.

[0027] The application also provides a preparation method of the above-mentioned anti-ultraviolet / salt-fog-resistant polyamide composite material, comprising the following steps:

[0028] S1, preparing a modified anti-ultraviolet agent salt; dissolving an amino-terminated modified anti-ultraviolet agent compound and a dibasic acid in anhydrous ethanol, and reacting at 50-80℃ under water bath conditions for 1-3h to obtain a modified anti-ultraviolet agent salt after filtration, washing and purification;

[0029] S2, preparing anti-ultraviolet polyamide master batch; adding modified anti-ultraviolet agent salt in polyhexamethylene adipate salt solution, and reacting for 0.5-2 h under the conditions of 200-230 DEG C and 2-3 MPa; after the pressure is reduced to normal pressure, adding antioxidant, and then reacting for 0.5-1 h under the conditions of -0.3 to -0.1 MPa and 260-290 DEG C, to obtain anti-ultraviolet polyamide master batch;

[0030] S3, mixing polyamide resin, anti-ultraviolet polyamide master batch and polydopamine modified hydrotalcite nano-particles uniformly, and then extruding, cutting and drying to obtain anti-ultraviolet / salt fog resistant polyamide composite material.

[0031] Further, in step S3, the polyamide resin, the anti-ultraviolet polyamide master batch and the polydopamine modified hydrotalcite nano-particles are mixed uniformly in a double-screw extruder, and the temperature of the feeding section of the double-screw extruder is 140-185 DEG C, and the temperature of other sections and the head is 190-260 DEG C; the screw rotation speed is 150-280 r / min.

[0032] Through the above scheme design, the application has the following effects:

[0033] The anti-ultraviolet / salt fog resistant polyamide composite material prepared by the application has more durable and stable anti-ultraviolet and salt fog resistant properties, and can maintain the excellent mechanical properties of the polyamide material itself.

[0034] The amino-terminated modified anti-ultraviolet agent compound is reacted with a dibasic carboxylic acid to obtain anti-ultraviolet agent salt, and then the anti-ultraviolet agent salt is compounded with polyhexamethylene adipate salt and antioxidant, so that the chemical bond of the anti-ultraviolet agent is connected into the molecular chain of the polyamide master batch to form high-dispersed anti-ultraviolet polyamide master batch, the compatibility of the anti-ultraviolet agent with the polyamide resin is improved, the phase separation in the traditional anti-ultraviolet agent and polyamide blending process is effectively solved, and the anti-ultraviolet aging property of the polyamide is improved.

[0035] The polydopamine modified hydrotalcite nano-particles are used to construct strong interfacial interaction with the polyamide resin by using the high-efficiency barrier property of the layered hydrotalcite particles to salt fog and the strong adhesion property of the polydopamine, so that the high-efficiency salt fog barrier property of the polydopamine modified hydrotalcite nano-particles is played, the plasticization and corrosion problems caused by the penetration of water molecules and salt substances into the polyamide resin are reduced, and the service life of the polyamide resin under salt fog working condition is prolonged. DETAILED DESCRIPTION

[0036] The technical solutions of the application will be described clearly and completely below by combining with the embodiments of the application. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the application.

[0037] It should be understood that the terms "comprises" and "comprising," when used in this specification and the following claims, indicate the presence of the described features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0038] It should also be understood that the terms used in the specification and the appended claims are intended to describe particular embodiments and do not intend to limit the present application. As used in the specification and the appended claims, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0039] It should further be understood that the term "and / or" used in the specification and the appended claims is intended to refer to any combination of one or more of the associated listed items and all possible combinations thereof.

[0040] In addition, the terms "substantially," "approximately," and the like are used herein to describe applicable embodiments that are not necessarily precise. For example, "substantially equal" does not mean absolute equality, as absolute equality is difficult to achieve in actual production and operation processes, and there is generally some deviation. Therefore, in addition to absolute equality, "substantially equal" also includes the above-mentioned case of having some deviation. By way of example, in other cases, unless otherwise specified, the terms "substantially," "approximately," and the like have similar meanings as described above.

[0041] Example 1

[0042] An anti-ultraviolet / salt-fog-resistant polyamide composite material is prepared by the following method:

[0043] S1, 5 parts of anti-ultraviolet agent A, 10 parts of toluene diisocyanate, and 0.1 parts of dibutyltin dilaurate are uniformly dispersed in 60 parts of acetone, heated to 40°C under nitrogen protection, and reacted for 2h; then, 20 parts of polyethylene glycol (molecular weight 1000g / mol), 5 parts of amino titanium dioxide nanoparticles are added and reacted at 70°C for 2h; further 1 part of propylene diamine is added and the reaction is continued at 60°C for 0.5h to obtain an amino-terminated modified anti-ultraviolet agent compound; wherein the anti-ultraviolet agent A comprises 3 parts of 4,4'-dihydroxybenzophenone and 2 parts of 2,2'-dihydroxy-4-methoxybenzophenone.

[0044] S2, 20 parts of the amino-terminated modified anti-ultraviolet agent compound, 10 parts of malonic acid are dissolved in 100 parts of anhydrous ethanol, and reacted at 50°C water bath for 1h, after filtration, washing and purification, a modified anti-ultraviolet agent salt is obtained;

[0045] S3, 15 parts of polyhexamethylene adipate salt is dissolved in 85 parts of deionized water to prepare a polyhexamethylene adipate salt solution with a mass concentration of 15%; then 20 parts of modified anti-ultraviolet agent salt is added into 100 parts of polyhexamethylene adipate salt solution, and the reaction kettle is kept at 200℃ and 2MPa for 0.5h; then, the pressure relief valve is adjusted to release the pressure in the reaction kettle to normal pressure, 0.3 parts of 2, 6-di-tert-butyl-4-methylphenol is added into the reaction kettle, the pressure relief valve is closed, the vacuum pump is started, and when the pressure in the reaction kettle is-0.3MPa, the reaction is carried out at 260℃ for 0.5h to obtain anti-ultraviolet polyamide master batch;

[0046] S4, 5 parts of tris-hydroxymethyl aminomethane is dissolved in 95 parts of deionized water, and the pH value of the solution is adjusted to 8.5 with hydrochloric acid to obtain a buffer solution. Then 5 parts of dopamine hydrochloride and 2 parts of layered hydrotalcite nanoparticles are added into the buffer solution, and the reaction is carried out at 30℃ for 5h. The obtained hydrotalcite nanoparticles are washed with deionized water until neutral, and dried until constant weight to obtain polydopamine modified hydrotalcite nanoparticles;

[0047] S5, 94 parts of PA1010 resin, 20 parts of anti-ultraviolet polyamide master batch and 2 parts of polydopamine modified hydrotalcite nanoparticles are uniformly mixed, then extruded through a double screw extruder (the temperature of feeding section is 140℃, and the screw rotation speed is 150r / min), and then cut and dried to obtain anti-ultraviolet / salt fog resistant polyamide composite material.

[0048] Example 2

[0049] A preparation method of anti-ultraviolet / salt fog resistant polyamide composite material is prepared by the following method:

[0050] S1, 18 parts of 2, 2'-dihydroxy-4-methoxybenzophenone, 33 parts of multifunctional isocyanate compound and 0.5 parts of dibutyl tin diacetate are uniformly dispersed in 80 parts of diethyl ether, heated to 50℃ under nitrogen protection and reacted for 2.5h; then, 28 parts of polypropylene glycol (molecular weight is 600g / mol), 6 parts of amino silica nanoparticles are added and reacted at 80℃ for 2.5h; further, 5 parts of hexanediamine is added and the reaction is continued at 75℃ for 0.6h to obtain amino-terminated modified anti-ultraviolet agent compound; wherein the multifunctional isocyanate compound includes isophorone diisocyanate and hexamethylene diisocyanate with a mass ratio of 1:2.

[0051] S2, 20 parts of amino-terminated modified anti-ultraviolet agent compound and 25 parts of adipic acid are dissolved in 100 parts of anhydrous ethanol, and the reaction is carried out at 60℃ water bath for 1.2h, then the modified anti-ultraviolet agent salt is obtained after filtration, washing and purification;

[0052] S3, 34 parts of polyhexamethylene adipate salt was dissolved in 66 parts of ionized water to configure a 34% polyhexamethylene adipate salt solution; then 39 parts of modified anti-ultraviolet agent salt was added in the polyhexamethylene adipate salt solution, and the reaction kettle was reacted at 220°C and 2.5 MPa for 1 h; then, the pressure relief valve was adjusted, the pressure in the reaction kettle was released to normal pressure, 0.5 parts of 2,6-di-tert-butyl-4-(dimethylaminomethyl) phenol was added into the reaction kettle, the pressure relief valve was closed, the vacuum pump was started, and when the pressure in the reaction kettle was-0.2 MPa, the reaction was carried out at 270°C for 0.8 h to obtain anti-ultraviolet polyamide master batch;

[0053] S4, 12 parts of trimethylol aminomethyl methane was dissolved in 88 parts of deionized water, and the pH value of the solution was adjusted to 8.5 with hydrochloric acid to obtain a buffer solution. Then 10 parts of dopamine hydrochloride and 5 parts of layered hydrotalcite nanoparticles were added in the buffer solution, and the reaction was carried out at 40°C for 6 h. The obtained hydrotalcite nanoparticles were washed with deionized water until neutral, and dried until constant weight to obtain polydopamine modified hydrotalcite nanoparticles;

[0054] S5, 85 parts of PA66 resin, 15 parts of anti-ultraviolet polyamide master batch, and 3 parts of polydopamine modified hydrotalcite nanoparticles were uniformly mixed, and then extruded through a double screw extruder (the temperature of the feeding section was 155°C, and the screw rotation speed was 200 r / min). After cutting and drying, an anti-ultraviolet / salt fog resistant polyamide composite material was obtained.

[0055] Example 3

[0056] A preparation method of an anti-ultraviolet / salt fog resistant polyamide composite material is prepared by the following method:

[0057] S1, 28 parts of 2,2',4,4'-tetrahydroxybenzophenone, 72 parts of dicyclohexyl methane diisocyanate, and 1.0 part of triethanolamine were uniformly dispersed in 90 parts of glacial acetic acid, heated to 70°C under nitrogen protection, and reacted for 2.2 h; then, 17 parts of 2,2-dimethylol butyric acid and 7 parts of anti-ultraviolet agent B were added and reacted at 90°C for 2.3 h; further, 6 parts of 1,4-butanediamine was added and the reaction was continued at 90°C for 1 h to obtain an amino-terminated modified anti-ultraviolet agent compound; wherein the anti-ultraviolet agent B includes propylene glycol nano-titanium dioxide and amino-silica nanoparticles with a mass ratio of 1:1;

[0058] S2, 38 parts of the amino-terminated modified anti-ultraviolet agent compound and 41 parts of dicarboxylic acid were dissolved in 100 parts of anhydrous ethanol, and reacted at 80°C water bath for 2.4 h; then, after filtration, washing and purification, a modified anti-ultraviolet agent salt was obtained;

[0059] S3, 29 parts of polyhexamethylene adipate salt was dissolved in 71 parts of ionized water to configure a 29% polyhexamethylene adipate salt solution; then 33 parts of modified anti-ultraviolet agent salt was added into the polyhexamethylene adipate salt solution, and the reaction kettle was reacted at 230°C and 3 MPa for 2 h; then, the pressure relief valve was adjusted, the pressure in the reaction kettle was released to normal pressure, 0.6 parts of tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester was added into the reaction kettle, the pressure relief valve was closed, the vacuum pump was started, and when the pressure in the reaction kettle was-0.1 MPa, the reaction was carried out at 290°C for 1 h to obtain anti-ultraviolet polyamide master batch;

[0060] S4, 20 parts of trimethylol aminomethyl methane was dissolved in 80 parts of deionized water, and the pH value of the solution was adjusted to 8.5 with hydrochloric acid to obtain a buffer solution. Then 20 parts of dopamine hydrochloride and 8 parts of layered hydrotalcite nanoparticles were added into the buffer solution, and the reaction was carried out at 50°C for 8 h. The obtained hydrotalcite nanoparticles were washed with deionized water until neutral, and dried until constant weight to obtain polydopamine modified hydrotalcite nanoparticles;

[0061] S5, 90 parts of PA6 resin, 13 parts of anti-ultraviolet polyamide master batch, and 4 parts of polydopamine modified hydrotalcite nanoparticles were uniformly mixed, and then extruded through a double screw extruder (the feeding section temperature was 165°C, and the screw rotation speed was 210 r / min). After cutting and drying, an anti-ultraviolet / salt fog resistant polyamide composite material was obtained.

[0062] Example 4

[0063] A preparation method of an anti-ultraviolet / salt fog resistant polyamide composite material is prepared by the following method:

[0064] S1, 40 parts of ethylene glycol salicylate, 80 parts of hexamethylene diisocyanate, and 5 parts of tributyl tin were uniformly dispersed in 95 parts of acetone, heated to 55°C under nitrogen protection, and reacted for 2 h; then, 70 parts of 4,5-dihydroxy-2-(hydroxymethyl) pentanoic acid and 7 parts of amino zinc oxide nanoparticles were added and reacted at 85°C for 2 h; further, 50 parts of 1,4-butanediamine was added and the reaction was continued at 80°C for 0.5 h to obtain an amino-terminated modified anti-ultraviolet agent compound;

[0065] S2, 5 parts of the amino-terminated modified anti-ultraviolet agent compound and 5 parts of sebacic acid were dissolved in 100 parts of anhydrous ethanol, and the reaction was carried out at 75°C water bath for 1.5 h; then, after filtration, washing and purification, a modified anti-ultraviolet agent salt was obtained;

[0066] S3, 50 parts of polyhexamethylene adipamide salt is dissolved in 50 parts of ionized water to configure a 50% polyhexamethylene adipamide salt solution; then 50 parts of modified anti-ultraviolet agent salt is added into the polyhexamethylene adipamide salt solution, and the reaction is carried out in a 2 MPa autoclave at 200°C for 1 h; then, the pressure in the autoclave is released to normal pressure by adjusting the pressure relief valve, and then 1.5 parts of bis(2,4-di-tert-butyl phenol) pentaerythritol diphosphite is added into the autoclave, the pressure relief valve is closed, the vacuum pump is started, and when the pressure in the autoclave is-0.2 MPa, the reaction is carried out at 270°C for 0.6 h to obtain anti-ultraviolet polyamide master batch;

[0067] S4, 2 parts of trimethylol aminomethane is dissolved in 98 parts of deionized water, and the pH value of the solution is adjusted to 8.7 by hydrochloric acid to obtain a buffer solution. Then 5 parts of dopamine hydrochloride and 1 part of layered hydrotalcite nanoparticles are added into the buffer solution, and the reaction is carried out at 30°C for 7 h. The obtained hydrotalcite nanoparticles are washed with deionized water until neutral, and dried until constant weight to obtain polydopamine modified hydrotalcite nanoparticles;

[0068] S5, 75 parts of PA46 resin, 20 parts of anti-ultraviolet polyamide master batch and 10 parts of polydopamine modified hydrotalcite nanoparticles are uniformly mixed, and then extruded through a double screw extruder (the feeding section temperature is 185°C, and the screw rotation speed is 150 r / min). After cutting and drying, an anti-ultraviolet / salt fog resistant polyamide composite material is obtained.

[0069] Example 5

[0070] A preparation method of an anti-ultraviolet / salt fog resistant polyamide composite material is prepared by the following method:

[0071] S1, 10 parts of ethylene glycol salicylate, 2 parts of toluene diisocyanate and 0.35 parts of dimethyl aminimidazole are uniformly dispersed in 100 parts of ethyl acetate, and heated to 40°C under nitrogen protection for 3 h; then, 5 parts of 2,2-dimethylol butyric acid, 5 parts of lysine diisocyanate and 7 parts of anti-ultraviolet agent B are added and reacted at 75°C for 3 h; further, 2 parts of 1,4-butanediamine is added and the reaction is continued at 80°C for 0.7 h to obtain an amino-terminated modified anti-ultraviolet agent compound; wherein the anti-ultraviolet agent B comprises amino titanium dioxide nanoparticles and amino silicon dioxide nanoparticles in a mass ratio of 2:3;

[0072] S2, 50 parts of the amino-terminated modified anti-ultraviolet agent compound and 50 parts of dicarboxylic acid are dissolved in 100 parts of anhydrous ethanol, and the reaction is carried out in a 55°C water bath for 3 h; then, after filtration, washing and purification, a modified anti-ultraviolet agent salt is obtained;

[0073] S3, 5 parts of polyhexamethylene adipamide salt was dissolved in 95 parts of ionized water to prepare a 5% polyhexamethylene adipamide salt solution; then 1 part of modified anti-ultraviolet agent salt was added to the polyhexamethylene adipamide salt solution, and the reaction was carried out in a 3 MPa autoclave at 210°C for 1.5 h; then, the pressure in the autoclave was released to normal pressure by adjusting the pressure relief valve, and then 0.5 parts of triethylene glycol bis-3-(3-tert-butyl-4-hydroxy-5-methylbenzyl) propionate was added to the autoclave, the pressure relief valve was closed, the vacuum pump was started, and when the pressure in the autoclave was-0.1 MPa, the reaction was carried out at 280°C for 1 h to obtain anti-ultraviolet polyamide master batch;

[0074] S4, 20 parts of tris-hydroxymethyl aminomethane was dissolved in 80 parts of deionized water, and the pH value of the solution was adjusted to 8.3 with hydrochloric acid to obtain a buffer solution. Then 15 parts of dopamine hydrochloride and 10 parts of layered hydrotalcite nanoparticles were added to the buffer solution, and the reaction was carried out at 50°C for 5 h. The obtained hydrotalcite nanoparticles were washed with deionized water until neutral, and dried until constant weight to obtain polydopamine modified hydrotalcite nanoparticles;

[0075] S5, 94 parts of PA1010 resin, 5 parts of anti-ultraviolet polyamide master batch, and 1 part of polydopamine modified hydrotalcite nanoparticles were uniformly mixed, and then extruded through a double screw extruder (the feeding section temperature was 140°C, and the screw rotation speed was 280 r / min). After cutting and drying, an anti-ultraviolet / salt mist resistant polyamide composite material was obtained.

[0076] Comparative Example 1

[0077] Comparative Example 1 is different from Example 1 in that the addition amount of propylene diamine is 0.5 parts, and the other components, preparation steps and parameters are consistent.

[0078] Comparative Example 2

[0079] Comparative Example 2 is different from Example 2 in that 2,2'-dihydroxy-4-methoxybenzophenone is used instead of anti-ultraviolet polyamide master batch, and the other components, preparation steps and parameters are consistent.

[0080] Comparative Example 3

[0081] Comparative Example 3 is different from Example 2 in that amino silica nanoparticles are used instead of anti-ultraviolet polyamide master batch, and the other components, preparation steps and parameters are consistent.

[0082] Comparative Example 4

[0083] Comparative Example 4 is different from Example 3 in that polydopamine modified hydrotalcite nanoparticles are not added, and the other components, preparation steps and parameters are consistent.

[0084] Comparative Example 5

[0085] Comparative Example 5 differs from Example 3 in that layered hydrotalcite nanoparticles are used instead of polydopamine modified hydrotalcite nanoparticles, and the rest of the components, preparation steps and parameters are consistent.

[0086] Comparative Example 6

[0087] Comparative Example 6 differs from Example 3 in that 18 parts of polydopamine modified hydrotalcite nanoparticles are added, and the rest of the components, preparation steps and parameters are consistent.

[0088] To illustrate the technical effect of the present application, the polyamide composite materials prepared in Examples 1-5 and Comparative Examples 1-6 are respectively melt injection molded into sample strips, and the tensile strength thereof is tested in accordance with GB / T 1040.2-2022; the bending strength thereof is tested in accordance with GB / T 9341-2008; and the notched impact strength thereof is tested in accordance with GB / T 1843-2008. The test results are shown in Table 1 below.

[0089] Table 1: Mechanical property test results of polyamide composite materials

[0090] Sample Tensile strength (MPa) Flexural strength (MPa) Impact strength (KJ / m 2 ) Example 1 92.23 161.21 22.49 Example 2 85.15 126.36 31.44 Example 3 75.89 105.34 24.68 Example 4 103.62 159.46 36.84 Example 5 90.72 162.59 23.05 Comparative Example 1 86.88 147.32 19.11 Comparative Example 2 79.44 115.12 27.80 Comparative Example 3 83.71 120.86 30.82 Comparative Example 4 67.78 80.52 19.77 Comparative Example 5 71.88 91.32 21.11 Comparative Example 6 55.72 60.59 17.38

[0091] As shown in Table 1, for Examples 1-5 of the present application, due to the strong interfacial interaction between the anti-ultraviolet polyamide masterbatch and the polydopamine modified hydrotalcite nanoparticles and the polyamide resin, both of them are uniformly dispersed in the polyamide resin, effectively improving the mechanical properties of the polyamide composite material. For Comparative Example 1, the addition amount of the diamine is too small, so that the modified anti-ultraviolet agent compound with amino-terminated cannot be generated, thereby it is difficult to obtain the anti-ultraviolet agent salt and the anti-ultraviolet polyamide masterbatch, which significantly affects the processing performance and mechanical properties of the polyamide composite material. For Comparative Example 2, the anti-ultraviolet agent is directly used to replace the anti-ultraviolet polyamide masterbatch for preparing the polyamide composite material, and the tensile strength and bending strength thereof are reduced. For Comparative Example 5, the layered hydrotalcite nanoparticles have weak interaction with the polyamide resin matrix, and are easy to agglomerate, resulting in the reduction of the tensile strength and bending strength of the composite material; for Comparative Example 6, a large amount of polydopamine modified hydrotalcite nanoparticles are difficult to disperse in the polyamide matrix, resulting in a significant reduction in the mechanical properties of the composite material.

[0092] To further illustrate the technical effect of the present application, the anti-ultraviolet and salt fog resistance tests are performed on the anti-ultraviolet / salt fog resistance polyamide composite materials of Examples 1-5 and Comparative Examples 1-6.

[0093] (1) Anti-ultraviolet test

[0094] The polyamide composite materials prepared in Examples 1-5 and Comparative Examples 1-6 were melt injection molded into sample strips, and the mechanical property retention rate and dimensional stability of the samples were tested after aging for 1000 h under ultraviolet light according to the method of GB / T 16422.2-2022. The test results are shown in Table 2 below:

[0095] Table 2 Mechanical properties and dimensional change rate of polyamide composite materials after 1000 h of ultraviolet aging

[0096]

[0097] As shown in Table 2, from Table 2, for Examples 1-3, due to the good ultraviolet aging resistance properties of the ultraviolet-resistant polyamide masterbatch, adding it to the polyamide matrix can significantly improve the ultraviolet resistance of the composite material, and after 1000 h of ultraviolet aging, the mechanical properties and dimensional changes are small. For Comparative Example 1, the ultraviolet aging resistance of the composite material is poor, and after aging for 1000 h in the ultraviolet environment, the mechanical properties and dimensional stability are significantly reduced. For Comparative Examples 2 and 3, 2,2'-dihydroxy-4-methoxybenzophenone and aminosilica nanoparticles are used instead of the ultraviolet-resistant polyamide masterbatch, the mechanical properties of the polyamide composite material are reduced, the dimensional change rate is significantly increased, and the overall ultraviolet aging resistance is low.

[0098] (2) Salt fog resistance test

[0099] The polyamide composite materials prepared in Examples 1-5 and Comparative Examples 1-6 were melt injection molded into sample strips, and the mechanical property retention rate and dimensional stability of the samples were tested after aging for 1000 h in a salt spray corrosion test chamber (LRHS-663-RY type) according to the method of GB / T 10125-2012. The test results are shown in Table 3 below:

[0100] Table 3 Mechanical properties and dimensional change rate of polyamide composite materials after 1000 h of salt spray aging

[0101]

[0102] As shown in Table 3, for Examples 1-5 and Comparative Examples 1-3, the polydopamine modified hydrotalcite nanoparticles with high barrier properties can effectively reduce the penetration of water molecules and salt substances into the resin matrix and the plasticizing and corrosion effects of the resin, and the mechanical properties of the polyamide composite material after 1000h of salt spray aging are still maintained at a high value, and the size change rate of the sample is small, showing good salt spray aging resistance. For Comparative Example 4, no polydopamine modified hydrotalcite nanoparticles are added, and after 1000h of salt spray aging, the mechanical properties of the polyamide composite material are significantly reduced, the size change rate of the sample is increased, and the salt spray aging resistance is weak. For Comparative Example 5, the dispersibility of the hydrotalcite nanoparticles in the polyamide matrix is poor, which greatly reduces the salt spray aging resistance. For Comparative Example 6, a large amount of polydopamine modified hydrotalcite nanoparticles are difficult to uniformly disperse in the polyamide matrix, and after long-term salt spray aging, the mechanical properties of the polyamide composite material are reduced, the size change rate of the sample is increased, and the salt spray aging resistance is low.

[0103] In summary, the anti-UV / salt spray resistant polyamide composite material of the present application has good stability, excellent anti-UV ability and salt spray resistance under the premise of ensuring its mechanical properties, and its mechanical properties can still be maintained at a high value after 1000h of UV aging or 1000h of salt spray aging, and the size change rate is small. When the technical solution of the present application is changed, it will have different degrees of negative effects on the stability of the final polyamide composite material, so that it cannot balance the mechanical properties, anti-UV ability and salt spray resistance.

[0104] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present application, and these modifications or replacements should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An ultraviolet resistant / salt fog resistant polyamide composite, characterized in that, Components including 70~94 parts of polyamide resin, 5~20 parts of anti-ultraviolet polyamide master batch and 1~10 parts of polydopamine modified hydrotalcite nanoparticles by mass fraction; The anti-ultraviolet polyamide master batch includes components with mass fraction of 50~99 parts of polyhexamethylene adipamide salt solution with mass concentration of 5~50%, 1~50 parts of modified anti-ultraviolet agent salt and 0.3~1.5 parts of antioxidant; the modified anti-ultraviolet agent salt is obtained by reaction of 5~50 parts of amino-terminated modified anti-ultraviolet agent compound and 5~50 parts of dicarboxylic acid in anhydrous ethanol; The polydopamine modified hydrotalcite nanoparticles include layered hydrotalcite nanoparticles and polydopamine coating layer on the surface of the nanoparticles; The amino-terminated modified anti-ultraviolet agent compound includes components with mass fraction of 5~40 parts of anti-ultraviolet agent A, 2~80 parts of multifunctional isocyanate compound, 10~70 parts of modifier, 5~10 parts of anti-ultraviolet agent B, 1~50 parts of diamine, 60~100 parts of solvent and 0.01~5 parts of catalyst; The amino-terminated modified anti-ultraviolet agent compound is prepared by the following method: uniformly dispersing the anti-ultraviolet agent A, multifunctional isocyanate compound and catalyst in the solvent, heating to 40~70℃ under a protective atmosphere for 2~3h; then adding the modifier and anti-ultraviolet agent B and reacting at 70~90℃ for 2~3h; finally adding the diamine and continuing to react at 60~100℃ for 0.5~1h to obtain the amino-terminated modified anti-ultraviolet agent compound; The anti-ultraviolet agent A is selected from at least one of 4,4'-dihydroxybenzophenone, 2,4-dihydroxybenzophenone, 3,4-dihydroxybenzophenone, 2,2'-dihydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2,2'-hydroxy-4-methoxybenzophenone and ethylene glycol salicylate; The anti-ultraviolet agent B is selected from at least one of PEG functionalized nano-silica, aminated titanium dioxide nanoparticles, aminated silica nanoparticles and aminated zinc oxide nanoparticles; The modifier is selected from at least one of polyethylene glycol, polypropylene glycol, 2,2-dimethylol butyric acid, 2,2-dimethylol propionic acid, 3,5-dihydroxy-3-methyl valeric acid and 4,5-dihydroxy-2-(hydroxymethyl) valeric acid; The polydopamine modified hydrotalcite nanoparticles are obtained by reaction of 5~20 parts of dopamine hydrochloride and 1~10 parts of layered hydrotalcite nanoparticles in a buffer solution with pH of 8.3~8.7; the buffer solution is a 2~20% trimethylolamine solution by mass concentration.

2. The ultraviolet resistant / salt fog resistant polyamide composite of claim 1, wherein, The diamine is selected from at least one of ethylenediamine, propylenediamine, hexamethylenediamine, 1,4-butanediamine, 1,5-pentanediamine and 1,6-hexanediamine.

3. The ultraviolet resistant / salt fog resistant polyamide composite of claim 1, wherein, The catalyst is selected from any one of dibutyl tin, tributyl tin, triethylenediamine, dibutyl tin dilaurate, dibutyl tin diacetate, triethanolamine and dimethylaminoimidazole.

4. A process for the preparation of the anti-UV / salt mist resistant polyamide composite according to any one of claims 1-3, characterized in that, The method includes the following steps: S1, preparing a modified anti-ultraviolet agent salt; The amino-terminated modified anti-ultraviolet agent compound and the dicarboxylic acid are dissolved in anhydrous ethanol, and reacted at 50-80 DEG C in a water bath for 1-3 hours. After filtration, washing and purification, the modified anti-ultraviolet agent salt is obtained; S2, preparing anti-ultraviolet polyamide master batch; adding the modified anti-ultraviolet agent salt into the polyhexamethylene adipate salt solution, and reacting at 200-230 DEG C and 2-3 MPa for 0.5-2 hours; after the pressure is reduced to normal pressure, adding an antioxidant, and then reacting at-0.3--0.1 MPa and 260-290 DEG C for 0.5-1 hour, to obtain the anti-ultraviolet polyamide master batch; S3, mixing the polyamide resin, the anti-ultraviolet polyamide master batch and the polydopamine modified hydrotalcite nanoparticles uniformly, extruding, cutting and drying to obtain the anti-ultraviolet / salt fog resistant polyamide composite material.

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