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CN-121975314-A - Polyamide composition and preparation method and application thereof

CN121975314ACN 121975314 ACN121975314 ACN 121975314ACN-121975314-A

Abstract

The invention discloses a polyamide composition, a preparation method and application thereof. The polyamide composition comprises, by weight, 33-72 parts of polyamide resin, 0.5-3 parts of an anti-hydrolysis agent, 20-45 parts of a reinforcing filler and 0.5-3 parts of a hindered phenol antioxidant, wherein the anti-hydrolysis agent comprises at least two of an oxazoline anti-hydrolysis agent, a carbodiimide anti-hydrolysis agent, a hindered amine anti-hydrolysis agent or an epoxy anti-hydrolysis agent, the molecular weight of the hindered phenol antioxidant is more than or equal to 500, and the phenolic hydroxyl content is more than or equal to 3.38mmol/g. According to the invention, the hindered phenol antioxidant with specific molecular weight and phenolic hydroxyl content and the specific anti-hydrolysis agent are added into the polyamide resin, so that the retention rate of heat retention viscosity and the retention rate of ageing property of the polyamide composition can be effectively improved, and the welding tensile strength is higher, and the polyamide composition is particularly suitable for water heater liner materials.

Inventors

  • JIANG XI
  • DING CHAO
  • YE SHIBING
  • WU CHANGBO
  • ZHOU CHENXU
  • ZHOU HUALONG
  • XU HONGJI

Assignees

  • 金发科技股份有限公司

Dates

Publication Date
20260505
Application Date
20260123

Claims (10)

  1. 1. A polyamide composition characterized by comprising the following components in parts by weight: 33-72 parts of polyamide resin; 0.5-3 parts of an anti-hydrolysis agent; 20-45 parts of reinforcing filler; 0.5-3 parts of hindered phenol antioxidant; Wherein the hydrolysis inhibitor comprises at least two of oxazoline hydrolysis inhibitor, carbodiimide hydrolysis inhibitor, hindered amine hydrolysis inhibitor or epoxy hydrolysis inhibitor, and the molecular weight of the hindered phenol antioxidant is more than or equal to 500, and the phenolic hydroxyl content is more than or equal to 3.38mmol/g.
  2. 2. The polyamide composition according to claim 1, wherein the hindered phenol antioxidant has a molecular weight of 650-1200 and a phenolic hydroxyl group content of 3.4-4.5 mmol/g, preferably the hindered phenol antioxidant has a molecular weight of 720-1000 and a phenolic hydroxyl group content of 3.5-4.2 mmol/g.
  3. 3. The polyamide composition of claim 1 wherein the carbodiimide type hydrolysis resistance agent comprises one or more of dicyclohexylcarbodiimide, N '-diisopropylcarbodiimide, 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride, or N, N' -bis (2, 6-diisopropylphenyl) carbodiimide, the epoxy type hydrolysis resistance agent comprises one or more of phenylglycidyl ether, triglycidyl isocyanate, or 3-glycidyletheroxy propyl trimethoxysilane, the oxazoline hydrolysis resistance agent comprises oxazoline and 2,2 '-bis (2-oxazoline), and the hindered amine type hydrolysis resistance agent comprises N, N' -bis- (2, 6-tetramethyl-4-piperidinyl) -1, 6-hexamethylenediamine and/or 2, 6-tetramethyl-4-piperidinol.
  4. 4. The polyamide composition according to claim 1, wherein the hydrolysis inhibitor is a carbodiimide hydrolysis inhibitor and a hindered amine hydrolysis inhibitor, and preferably the mass ratio of the carbodiimide hydrolysis inhibitor to the hindered amine hydrolysis inhibitor in the hydrolysis inhibitor is (0.3-3): 1.
  5. 5. The polyamide composition according to claim 1, wherein the polyamide resin has an amino end group content of 20 to 90mmol/kg, preferably 30 to 50mmol/kg.
  6. 6. The polyamide composition according to claim 1, wherein the reinforcing filler comprises one or more of glass fiber, carbon fiber, basalt fiber or aramid fiber, preferably the reinforcing filler has an average diameter of 10 to 13 μm.
  7. 7. Polyamide composition according to claim 1, characterized in that it comprises the following components in parts by weight: 40-70 parts of polyamide resin; 0.8-2 parts of an anti-hydrolysis agent; 22-40 parts of reinforcing filler; 0.6-1.5 parts of hindered phenol antioxidant.
  8. 8. A process for the preparation of a polyamide composition according to any one of claims 1 to 7, comprising the steps of: S1, uniformly mixing other components except the reinforcing filler according to a proportion to obtain a premix; S2, feeding the premix in the step S1 into an extruder through a main feeding port, feeding glass fibers into the extruder through a side feeding port, and carrying out melt blending, extrusion and granulation to obtain the polyamide composition.
  9. 9. Use of the polyamide composition according to any one of claims 1 to 7 for the preparation of electronic appliances, household appliances.
  10. 10. A water heater, comprising a liner body made from the polyamide composition of any one of claims 1-7.

Description

Polyamide composition and preparation method and application thereof Technical Field The invention relates to the technical field of engineering plastics, in particular to a polyamide composition, a preparation method and application thereof. Background The metal enamel liner of the electric water heater is already mature in the industry, but the metal enamel liner has the problems of water leakage caused by metal corrosion after long-time use, leakage risk caused by the fact that the liner body is made of metal materials, and influence on water quality caused by a large amount of water scales after long-time use of the enamel liner. Polyamide resins have excellent toughness and electrical insulation properties, but polyamide resins themselves are not high in strength and insufficient in heat resistance, and the problems of insufficient strength and heat resistance are usually solved by adding reinforcing fillers into the polyamide resins, so that glass fiber reinforced polyamide materials have better rigidity and toughness, and are one of the most preferred materials for replacing steel with plastic. However, the injection molding period of the liner of the electric water heater is longer, and the conventional glass fiber reinforced polyamide material is easy to degrade in the injection molding process, so that the problems of air marks on the appearance of a finished piece, mold scales on a mold and the like are caused, and the application requirements cannot be met. Disclosure of Invention The invention provides a polyamide composition for overcoming the defect that glass fiber reinforced polyamide materials are easy to degrade in the injection molding cycle of an electric water heater liner in the prior art. It is another object of the present invention to provide a process for preparing the polyamide composition. It is a further object of the present invention to provide the use of said polyamide composition. In order to achieve the above purpose, the invention adopts the following technical scheme: a polyamide composition comprising the following components in parts by weight: 33-72 parts of polyamide resin; 0.5-3 parts of an anti-hydrolysis agent; 20-45 parts of reinforcing filler; 0.5-3 parts of hindered phenol antioxidant; Wherein the hydrolysis inhibitor comprises at least two of oxazoline hydrolysis inhibitor, carbodiimide hydrolysis inhibitor, hindered amine hydrolysis inhibitor or epoxy hydrolysis inhibitor, and the molecular weight of the hindered phenol antioxidant is more than or equal to 500, and the phenolic hydroxyl content is more than or equal to 3.38mmol/g. The invention provides a polyamide composition, which can effectively improve the retention rate of heat retention viscosity number, namely the degradation resistance of a material is improved in a long injection molding period, the viscosity number is kept better, the aging performance retention rate and the welding tensile strength are higher, and particularly, a specific antioxidant can capture free radicals in a system to prevent degradation, and meanwhile, the hydrolysis inhibitor can neutralize amino and carboxyl generated by the rupture of an amide bond in the polyamide resin, so that the comprehensive performance of the polyamide composition is improved under the combined action of the antioxidant and the hydrolysis inhibitor. In the polyamide composition of the present invention, the polyamide resin content is preferably not less than 35% by weight, and preferably not less than 40% by weight. Preferably, the amino end content of the polyamide resin is 20-90 mmol/kg. More preferably, the amino end group content of the polyamide resin is 30-50 mmol/kg. Specifically, the amino-terminated content of the polyamide resin is determined by a potentiometric titration method. Specifically, the potentiometric titration method is to weigh 1.0g (0.0001 g accurately) of polyamide resin into a titration cup, add 50mL of trifluoroethanol, heat and stir at 65 ℃ until the polyamide resin is completely dissolved, insert an electrode and a titration head after the polyamide resin is completely dissolved, titrate to an end point by using a hydrochloric acid standard solution (0.1 mol/L) after the potential is stable (titration is carried out, meanwhile, a change curve of pH with the titration volume is recorded, the corresponding volume of a curve jump point is the end point), record the volume Vc of the consumed hydrochloric acid standard solution, and pass through the end amino content= (Vc-V 0) multiplied by C multiplied by 1000/m, wherein C is the concentration of the hydrochloric acid standard solution, vc is the volume of the hydrochloric acid standard solution consumed by a sample, V0 is the volume of the hydrochloric acid standard solution consumed by blank trifluoroethanol, and m is the mass of the sample. Preferably, the relative viscosity of the polyamide resin is 1.6-3.0. Specifically, the polyamide resin has a relative viscosity ac