A polyamide composite material and its preparation method and application

Abstract

The present invention belongs to the technical field of engineering plastics, and specifically relates to a polyamide composite material, a preparation method thereof, and an application thereof. The polyamide composite material comprises the following components in parts by weight: 50-100 parts of nylon resin, 1-10 parts of epoxy resin, 0.1-5 parts of polyol, 2-10 parts of zinc ion ionomer, and 5-30 parts of glass fiber. The polyamide composite material prepared by the present invention can effectively improve the thermal stability of the material and avoid the degradation of the material at high temperature, so that the composite material can still maintain a high weld mark strength and excellent resilience and mechanical properties under high temperature and high humidity environment, and has a broader material application space.

Description

Technical Field

[0001] The invention belongs to the technical field of engineering plastics, and specifically relates to a polyamide composite material and a preparation method and application thereof. Background Art

[0002] Nylon is widely used as an engineering material in various fields. With the continuous improvement of technology, the variety of products is increasing. However, with the development of modern high technology, products with durability, chemical resistance and complex structural design are gradually increasing, which puts higher requirements on the comprehensive performance of materials. While the material needs to meet the characteristics of high strength and high heat resistance, it must also maintain good comprehensive performance under high temperature, high humidity and high stress conditions. As one of the representatives of high-strength and high-heat-resistant materials, nylon has the disadvantage of easy water absorption. After water absorption, the thermal stability, dimensional stability and performance retention rate of the material will decrease to varying degrees, which will bring certain resistance during use. In order to further expand its application, colleagues in the industry have also conducted different related research.

[0003] Chinese patent CN110791085A discloses a method of using carboxyl compounds to improve the weld strength in glass fiber reinforced nylon materials, but since carboxyl compounds are acidic substances, they have a significant impact on the strength of the material. Chinese patent CN115536798A discloses a method of using polyols as reaction components in polyurethane materials to prepare polyurethane composite materials, but the injection weld marks of the prepared polyurethane composite materials are very different from those of polyamide materials.

[0004] Therefore, in polyamide modification, materials that can meet the requirements of high weld mark and high resilience in a specific environment are rarely encountered. In order to fill the current technical gap, this patent provides a technical solution. Summary of the invention

[0005] The present invention aims to provide a polyamide composite material and a preparation method and application thereof. The polyamide composite material prepared by the present invention can still maintain good weld mark strength and excellent material resilience after being exposed to high temperature and high humidity environment.

[0006] In order to achieve the above purpose, the present invention adopts the following technical scheme: a polyamide composite material, comprising the following components in parts by weight: 50-100 parts of nylon resin, 1-10 parts of epoxy resin, 0.1-5 parts of polyol, 2-10 parts of zinc ionomer, and 5-30 parts of glass fiber.

[0007] Preferably, the polyamide composite material comprises the following components in parts by weight: 68-80 parts of nylon resin, 5-8 parts of epoxy resin, 1.0-1.5 parts of polyol, 5-7 parts of zinc ionomer, and 20-25 parts of glass fiber.

[0008] Preferably, the terminal amino group content of the nylon resin is 45 to 110 mmol / kg.

[0009] Preferably, the terminal amino group content of the nylon resin is 45 to 85 mmol / kg.

[0010] The test method for the terminal amino group content of the nylon resin of the present invention is: dissolving the nylon resin in 2.2.2-trifluoroethanol and titrating the amino group with a 0.02 mol / L hydrochloric acid aqueous solution.

[0011] Preferably, the relative viscosity of the nylon resin is 2.6-2.7. The relative viscosity of the nylon resin of the present invention is tested according to ISO 307 (using concentrated sulfuric acid as a solvent and dissolving at room temperature).

[0012] Preferably, the nylon resin includes at least one of PA66, PA610 and PA1010.

[0013] Preferably, the mass ratio of the epoxy resin, the polyol and the zinc ionomer is (1-10):(0.1-5):(2-10).

[0014] Preferably, the zinc ionomer is a salinyl thermoplastic ionomer; the melt flow rate of the zinc ionomer under the test conditions of 190°C and 2.16kg is 0.3-10g / 10min. The melt flow rate of the zinc ionomer of the present invention is carried out according to the ASTM D1238-2010 version test standard.

[0015] Preferably, the zinc ion ionomer has a melt flow rate of 0.5-1.5 g / 10 min under test conditions of 190° C. and 2.16 kg.

[0016] More preferably, the zinc ionomer has a melt flow rate of 0.8-1.3 g / 10 min under the test conditions of 190° C. and 2.16 kg.

[0017] Preferably, the epoxy equivalent value of the epoxy resin is 1080-4500 g / eq.

[0018] Preferably, the epoxy equivalent value of the epoxy resin is 1300-4000 g / eq. The epoxy equivalent value of the epoxy resin of the present invention is tested according to GB / T 4612-2008.

[0019] Preferably, the polyol is pentaerythritol and / or dipentaerythritol.

[0020] Preferably, the glass fiber is alkali-free glass fiber.

[0021] Preferably, the polyamide composite material further comprises 1-5 parts of an auxiliary agent, wherein the auxiliary agent comprises at least one of a lubricant, a nucleating agent, an antistatic agent, and an antioxidant. The lubricant selected in the present invention can be selected from stearates, the nucleating agent can be selected from sodium fatty acids, the antistatic agent can be selected from ethoxylated fatty amines, and the antioxidant can be selected from phenolic antioxidants and other conventional components in the art.

[0022] In the polyamide composite material of the present invention, the content of the nylon resin is not less than 45%.

[0023] Preferably, the content of the nylon resin is above 60%.

[0024] The present invention adds epoxy resin, polyol and zinc ion ionomer to the polyamide material, and the epoxy group of the epoxy resin is combined with the amino group at the end of the polyamide resin molecular chain to form a micro-crosslinking structure, so that the intermolecular force is improved, and the surface density of the material is effectively improved, so that the material is effectively protected from the influence of the external environment and the thermal stability of the prepared material is enhanced; the hydroxyl group of the polyol in the formula system can chelate the zinc ion ionomer, inhibit the degradation of the nylon resin, and can give play to its own advantages to improve the toughness of the material, so as to effectively protect the material from the influence of the external high temperature and high humidity environment; at the same time, when heated, the thermal stability of the polyamide composite material can be better improved under the effect of overall synergy, so as to improve the weld mark strength of the material in a high temperature and high humidity environment and make the material have excellent resilience.

[0025] The present invention also claims a method for preparing the polyamide composite material, comprising the following steps:

[0026] All components except glass fiber are premixed, then melt-mixed with the glass fiber, and extruded and granulated to obtain the polyamide composite material.

[0027] Preferably, the melt mixing is performed using a twin-screw extruder, wherein the screw length-to-diameter ratio of the twin-screw extruder is 40-48:1.

[0028] Preferably, the glass fibers are fed from the side of a twin screw extruder.

[0029] Preferably, the temperature of the melt mixing is 230-260° C., and the rotation speed is 200-550 rpm.

[0030] The present invention also claims protection for an application of the polyamide composite material in the fields of electronics, new energy and industrial construction, specifically including new energy high-voltage connectors, photovoltaic end plates, building thermal insulation protective layers, etc.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The present invention can effectively improve the thermal stability of the prepared material and avoid degradation of the material at high temperature through the interaction between nylon resin, epoxy resin, polyol and zinc ion ionomer, so that the composite material can still maintain high weld mark strength and excellent resilience and mechanical properties in a high temperature and high humidity environment, and has a broader material application space. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] In the examples and comparative examples, the experimental methods used are conventional methods unless otherwise specified. Unless otherwise specified, the antioxidants are commercially available, and the same antioxidants are used in parallel experiments.

[0035] The raw materials used in the examples and comparative examples are shown in Table 1.

[0036] Table 1

[0037]

[0038]

[0039] Examples 1 to 11 and Comparative Examples 1 to 5

[0040] The components and weight proportions of the polyamide composite materials of Examples 1 to 11 and Comparative Examples 1 to 5 are shown in Table 2-3.

[0041] The preparation method of the polyamide composite material of Examples 1 to 11 and Comparative Examples 1 to 5 comprises the following steps:

[0042] All components except glass fiber are premixed, put into a twin-screw extruder for melt mixing, glass fiber side feeding, and extrusion granulation to obtain the polyamide composite material; wherein the twin-screw extruder has a screw length-to-diameter ratio of 40 to 48:1, a barrel temperature of 230 to 260°C, and a screw speed of 200 to 550 rpm.

[0043] Table 2 Component dosage (parts by weight)

[0044]

[0045] Table 3 Component dosage in comparative example (parts by weight)

[0046]

[0047]

[0048] Performance Testing

[0049] The polypropylene composite materials prepared in Examples 1 to 11 and Comparative Examples 1 to 5 were subjected to relevant performance tests. The test methods and standards are as follows. The experimental results are shown in Table 4.

[0050] Weld mark strength test:

[0051] The prepared material was injected into a 280T injection molding machine at 275°C, rated speed of 55%, and pressure of 50 bar to form a tensile weld line specimen. After the prepared specimen was dried at 120°C for 4 hours, a tensile weld line strength test was performed as the initial value. At the same time, the sample was taken out and placed in an environmental box with 90% humidity and 95°C for 200 hours, and then taken out and treated at 23°C and 50% humidity for 0.5h for a tensile weld line strength test. The ratio of the two is the weld line performance retention rate of the material.

[0052] Rebound resistance test:

[0053] According to the UL94-2014 standard, after injection molding a 125*10*1mm sample in a 50% humidity, 23°C environment for 24 hours, fold the sample 180 degrees, place 5kg weights on both ends of the sample, place it in a 100-degree environment for 100 hours, remove the weights, and test the angle formed by the sample. The larger the angle, the better the rebound performance. Among them, 0-30 degrees is level 1, 31-60 degrees is level 2, and more than 60 degrees is level 3.

[0054] Table 4 Performance test results

[0055]

[0056]

[0057] From the data in Table 4, it can be seen that the polyamide composite material prepared in the embodiment of the present invention has a high weld mark strength retention rate under high temperature and high humidity environment, and has excellent resilience. Among them, the weld mark strength retention rate can be maintained in the range of 70-78%, and the resilience can be maintained at level 2-3.

[0058] The weight fraction of epoxy resin added in Comparative Example 1 is not appropriate, and the weight fraction of zinc ionomer added in Comparative Example 2 is not appropriate. The weld mark strength retention rate of the obtained polyamide composite material in a high temperature and high humidity environment is lower than that of the embodiment, and the resilience thereof is deteriorated; no zinc ionomer is added in Comparative Example 3, and non-zinc ion ionomer is used to replace zinc ionomer in Comparative Example 4. The weld mark strength retention rate and resilience of the obtained polyamide composite material are worse than those of the embodiment; other resins (ethylene-octene copolymer) are used to replace epoxy resin in Comparative Example 5. The weld mark strength retention rate of the obtained composite material in a high temperature and high humidity environment is poor, and the resilience thereof is also poor.

[0059] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A polyamide composite material, characterized in that: The invention comprises the following components in parts by weight: 50-100 parts of nylon resin, 1-10 parts of epoxy resin, 0.1-5 parts of polyol, 2-10 parts of zinc ionomer, and 5-30 parts of glass fiber; The terminal amino group content of the nylon resin is 45-110 mmol / kg; The relative viscosity of the nylon resin is 2.6-2.7; the relative viscosity of the nylon resin is tested according to ISO 307, using concentrated sulfuric acid as a solvent and dissolving at room temperature; The zinc ionomer is a salin-based thermoplastic ionomer; The epoxy equivalent value of the epoxy resin is 1080-4500 g / eq; The polyol is pentaerythritol and / or dipentaerythritol.

2. The polyamide composite material according to claim 1, characterized in that: The invention comprises the following components in parts by weight: 68-80 parts of nylon resin, 5-8 parts of epoxy resin, 1.0-1.5 parts of polyol, 5-7 parts of zinc ionomer and 20-25 parts of glass fiber.

3. The polyamide composite material according to claim 1, characterized in that: The nylon resin includes at least one of PA66, PA610 and PA1010.

4. The polyamide composite material according to claim 1, characterized in that: The zinc ion ionomer has a melt flow rate of 0.3-10 g / 10 min under the test conditions of 190° C. and 2.16 kg.

5. The polyamide composite material according to claim 1, characterized in that: The glass fiber is alkali-free glass fiber.

6. The polyamide composite material according to claim 1, characterized in that: The polyamide composite material further comprises 1-5 parts of auxiliary agents, wherein the auxiliary agents comprise at least one of lubricants, nucleating agents, antistatic agents and antioxidants.

7. A method for preparing a polyamide composite material according to any one of claims 1 to 6, characterized in that: The following steps are involved: All components except glass fiber are premixed, then melt-mixed with the glass fiber, and extruded and granulated to obtain the polyamide composite material.

8. The preparation method according to claim 7, characterized in that: At least one of the following (1) to (3): (1) The melt mixing is performed using a twin-screw extruder, wherein the screw length-to-diameter ratio of the twin-screw extruder is 40-48:1; (2) The glass fiber is fed from the side of the twin-screw extruder; (3) The temperature of the melt mixing is 230-260°C and the rotation speed is 200-550 rpm.

9. Use of the polyamide composite material according to any one of claims 1 to 6 in the fields of electronics and electrical, new energy and industrial construction.

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