CN-121160079-B - Modified PA6 material and preparation method thereof

CN121160079BCN 121160079 BCN121160079 BCN 121160079BCN-121160079-B

Abstract

The invention belongs to the technical field of modified copolymerized nylon, and particularly relates to a modified PA6 material and a preparation method thereof. The invention aims to solve the problems that the conventional copolymerization modified PA6 material is strong in hygroscopicity and does not have high insulativity. The invention discloses a preparation method of a modified PA6 material, which comprises the steps of mixing and copolymerizing caprolactam and laurolactam to obtain a PA6/12 random copolymer, pre-blending modified graphene oxide, boron nitride nanosheets and polyamide oligomers to obtain a composite suspension, coating the surface of the PA6/12 random copolymer, feeding the PA6/12 random copolymer into an extruder, completely melting the PA6 random copolymer, adding the composite suspension, uniformly mixing the PA6 random copolymer, adding a flame retardant auxiliary agent, and finally extruding the PA6 random copolymer to obtain the modified PA6 material. The modified PA6 material prepared by the invention has low water absorption and good insulativity, and is not easy to leak and trace in a high-temperature working scene.

Inventors

WENG HAOXUAN
Qi Dahao
SHEN XINGLIAN

Assignees

江苏达威新材料技术有限公司

Dates

Publication Date: 20260508
Application Date: 20251021

Claims (3)

1. A preparation method of a modified PA6 material is characterized by comprising the following steps: mixing caprolactam and laurolactam according to a molar ratio of 85:15, and carrying out copolymerization reaction to obtain a PA6/12 random copolymer; Carrying out surface coating treatment on the PA6/12 random copolymer and modified hydrotalcite; wherein the modified hydrotalcite is obtained by treating aluminum-magnesium hydrotalcite powder with sodium stearate; 100 parts of the PA6/12 random copolymer is fed into an extruder, a composite suspension is added after melting, the temperature is raised at the later stage of extrusion, 15 parts of flame retardant auxiliary agent is added, and the modified PA6 material is obtained after extrusion; According to the operation sequence of the extruder barrel, the feeding sequence is that a first barrel is a main feeding port, the operation temperature is 260 ℃, the PA6/12 random copolymer subjected to surface coating treatment is added, a second barrel to a fourth barrel are melt plasticizing areas, the composite suspension is added in a fifth barrel area through a metering pump, a sixth barrel is a conventional stretching shearing treatment part, a seventh barrel is a side feeding port, the flame retardant auxiliary is added and mixed, the operation temperature is increased to 280 ℃, an eighth barrel is a conventional stretching shearing treatment part, a ninth barrel is an exhaust area, the operation pressure is 0.1atm, and the tenth barrel to the twelfth barrel are homogenizing pressure areas, and finally melt is extruded through weak shearing force; The composite suspension comprises polyamide oligomer, boron nitride nano-sheets and modified graphene oxide; the surface coating treatment process comprises mixing the PA6/12 random copolymer and the modified hydrotalcite for 5-10min under stirring; dispersing graphene oxide in deionized water, adding ethylenediamine, performing water bath reaction, and washing and drying the obtained solid product to obtain the modified graphene oxide; the preparation method of the composite suspension comprises the steps of heating the polyamide oligomer, adding the modified graphene oxide dispersion liquid into the heated polyamide oligomer, adding the boron nitride nanosheets after ultrasonic homogenization, and carrying out vacuum treatment after uniform mixing to obtain the composite suspension; The flame retardant auxiliary comprises melamine phosphate and zinc borate, wherein the polyamide oligomer is a hydroxyl-terminated PA6 oligomer; The addition mass ratio of the PA6/12 random copolymer to the composite suspension is 100:25-35.
2. The method of claim 1, wherein the copolymerization reaction is carried out at a temperature of 260-280 ℃.
3. A modified PA6 material is characterized in that the modified PA6 material is prepared by the preparation method of any one of claims 1-2.

Description

Modified PA6 material and preparation method thereof Technical Field The invention belongs to the technical field of modified copolymerized nylon, and particularly relates to a modified PA6 material and a preparation method thereof. Background Nylon materials are one of the most widely used and most productive engineering plastics, including PA6, PA66, PA46, etc., and have important application value in various fields due to their excellent tensile strength, abrasion resistance, chemical resistance and relatively low cost. Among them, PA6 (polycaprolactam) is a typical nylon material, and its molecular chain contains a large amount of polar amide groups, which are easily absorbed by water during use, resulting in slow decrease of rigidity and strength over a certain period of time. Meanwhile, PA6 is susceptible to swelling after water absorption, resulting in dimensional changes of parts, which is a fatal defect for applications requiring high precision (e.g., electronic connectors, precision gears). Therefore, the modified PA6 material gradually replaces the basic PA6 material, and is focused by industry, such as copolymerization modified PA6, composite modified PA6 and the like, and the mechanical property and the functionality of the modified PA6 material are improved to a certain extent. The modified PA6 material has been widely used in the fields of new energy automobiles, new construction, advanced manufacturing industry and the like. Although the modification technology of PA6 is already quite mature, there are some key technical problems. Although the copolymerization modification can reduce the water absorption, this is usually at the expense of heat resistance or increased cost. In fiber reinforced composite materials, even if the PA6 matrix is low in hygroscopicity, poor interfaces between fibers and the matrix can become capillary channels for moisture permeation, and the problem of hygroscopicity is reintroduced, and furthermore, in order to improve the mechanical property of modified PA6, the addition of various fillers limits the composite functionality, nano fillers or powdery auxiliary agents are extremely easy to agglomerate in a melt to form stress concentration points, and the material property is weakened instead. Meanwhile, inorganic fillers are naturally incompatible with organic PA6 matrices, and efficient compatibilizer techniques must be relied upon to build a robust interface bond. In particular, in the field of insulating assembly used in the fields of high-voltage battery modules, precision engineering appliances and the like, the conventional modified PA6 material has insulativity, but also has obvious electric leakage tracking during long-term high-temperature and high-voltage operation. In order to solve the problems of strong hygroscopicity and no high insulativity of the conventional copolymerization modified PA6 material, a modified PA6 material and a preparation method thereof are provided. Disclosure of Invention The invention aims to provide a modified PA6 material and a preparation method thereof. The invention discloses a preparation method of a modified PA6 material, which comprises the steps of mixing and copolymerizing caprolactam and laurolactam to obtain a PA6/12 random copolymer, pre-blending modified graphene oxide, boron nitride nanosheets and polyamide oligomers to obtain a composite suspension, coating the surface of the PA6/12 random copolymer, feeding the PA6/12 random copolymer into an extruder, completely melting the PA6 random copolymer, adding the composite suspension, uniformly mixing the PA6 random copolymer, adding a flame retardant auxiliary agent, and finally extruding the PA6 random copolymer to obtain the modified PA6 material. In order to achieve the above purpose, the present invention provides the following technical solutions: The preparation method of the modified PA6 material comprises the following steps: Unless otherwise specified, parts in the present invention refer to parts by mass. And (3) under the protection of nitrogen, mixing caprolactam and laurolactam according to a molar ratio of 85:15, heating to 260-280 ℃ by taking oxalic acid as an initiator, and reacting for 12 hours under the operating pressure of 1.5 MPa. Extruding the polymer melt into strips, cooling, extracting with hot water to remove unreacted monomers and oligomers, and drying to obtain the PA6/12 random copolymer. 100 Parts of PA6/12 random copolymer and 2 parts of modified hydrotalcite are mixed for 5-10min at a rotating speed of 1500rpm, and surface coating treatment is carried out. The preparation method of the modified hydrotalcite comprises dispersing 100 parts of aluminum-magnesium hydrotalcite powder in ethanol, dripping sodium stearate solution, stirring for 4 hours at 70 ℃, washing the obtained solid product with hot water and ethanol, and drying to obtain the modified hydrotalcite. Wherein the ratio of magnesium to aluminum in the aluminum-magnesium hydr