Glass fiber reinforced PA12-PA6T composite material and preparation method thereof

Abstract

The invention discloses a glass fiber reinforced PA12-PA6T composite material and a preparation method thereof, the composite material comprises the following components by weight: 40%-65% of PA12 resin, 10%-15% of PA6T resin, 10%-20% of glass fiber, 10%-20% of a compound flame retardant, 5%-10% of a CTI improver, 1.5%-5% of an antioxidant, and 1.5%-5% of a compatilizer. According to the invention, the PA12 / PA6T composite material is reinforced and modified by using the surface-modified glass fiber, the glass fiber can be uniformly dispersed in the resin and has good interfacial compatibility with the resin, and the mechanical properties are also improved. The compounded flame retardant has good dispersity in resin, a combustion carbon layer is migrated to the surface of a resin carbon layer, and the combustion carbon layer and the resin carbon layer are combined to form a more compact carbon layer, so that heat conduction between a polymer and a heat source is more favorably blocked, the flame retardance of the composite material is effectively improved, and the glowing filament of the material is obviously improved. And the compounded CTI auxiliary agent can enable the resin to be stacked in a discontinuous form, and is beneficial to improving the tracking index of the material.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a glass fiber reinforced PA12-PA6T composite material and a preparation method thereof. Background Art

[0002] Nylon (PA) 12 is a semi-crystalline polymer with good wear resistance, thermal stability and mechanical properties. Among PA products, PA12 has the lowest melting temperature, low water absorption and shrinkage, and is used in automotive connectors, terminals, sheaths, fuse boxes, lamp holders, cable ties and other automotive electrical appliances. With the development of automotive electrical products, people's demand for automotive electrical products has become wider, and there is an urgent need for modified nylon materials with high strength, high heat resistance, halogen-free flame retardancy and other enhanced properties. Summary of the invention

[0003] Based on the deficiencies of the prior art, the object of the present invention is to provide a glass fiber reinforced PA12-PA6T composite material and a preparation method thereof, wherein the composite material has the characteristics of good flame retardancy and a high tracking index.

[0004] In order to achieve the above purpose, this application adopts the following technical solutions:

[0005] In the first aspect, the present invention provides a glass fiber reinforced PA12-PA6T composite material, which includes the following components by weight percentage: 40%-65% PA12 resin, 10%-15% PA6T resin, 10%-20% glass fiber, 10%-20% compound flame retardant, 5%-10% CTI enhancer, 1.5%-5% antioxidant, and 1.5%-5% compatibilizer.

[0006] In the above technical solution, the glass fiber is a glass fiber treated with surface silane.

[0007] In the above technical solution, the compound flame retardant is a flame retardant masterbatch prepared by mixing the modified microencapsulated aluminum hypophosphite flame retardant and the MCA flame retardant in a mass ratio of 2:1.

[0008] In the above technical scheme, the preparation method of the modified microencapsulated aluminum hypophosphite flame retardant is: mixing melamine formaldehyde prepolymer and ammonium polyphosphate in a mass ratio of 1: (2 to 3) to obtain a suspension; subjecting the suspension to an in-situ polymerization reaction at a temperature of 100° C. to 120° C. for 6 to 12 hours, and then drying to obtain the modified microencapsulated aluminum hypophosphite flame retardant.

[0009] In the above technical solution, the CTI enhancer is prepared by mixing modified boehmite and zinc borate in a mass ratio of 2:1.

[0010] In the above technical scheme, the preparation method of the modified boehmite is: weigh a certain mass of boehmite, add 0.5-2.5% of the mass of the boehmite diluted with isopropanol phthalate coupling agent, stir and mix at high speed and then dry to obtain the modified boehmite.

[0011] In the above technical solution, the antioxidant is at least one of hindered phenol antioxidants.

[0012] In the above technical solution, the compatibilizer is at least one of maleic anhydride grafted polypropylene copolymer and maleic anhydride grafted polyethylene copolymer.

[0013] In a second aspect, the present invention provides a method for preparing the composite material, comprising the following steps:

[0014] S1: drying the PA12 resin, PA6T resin, glass fiber, compound flame retardant, CTI enhancer, antioxidant and compatibilizer;

[0015] S2: premixing the dried PA12 resin, PA6T resin, compound flame retardant, CTI enhancer, antioxidant and compatibilizer to obtain an initial mixture;

[0016] S3: The initial mixture is fed into the main feeder hopper of a twin-screw extruder, and conveyed by its own gravity and the main feeder screw. At the same time, the dried glass fiber is added to the side feeder hopper, and conveyed to the screw cavity of the twin-screw extruder by the side feeder screw. After heating and melting by the heated barrel and screw shearing, and extrusion granulation, the composite material is obtained.

[0017] In the above technical solution, the processing temperature of the twin-screw extruder is controlled at 280-310° C., and the main engine speed is 300-350 rpm.

[0018] The beneficial effects of the present invention are as follows: the present invention uses surface-modified glass fiber to enhance and modify the PA12 / PA6T composite material, the glass fiber can be evenly dispersed in the resin, and has good interface compatibility with the resin, and the mechanical properties are also improved. The compounded flame retardant has good dispersibility in the resin, and the burning carbon layer migrates to the surface of the resin carbon layer. The two combine to form a denser carbon layer, which is more conducive to blocking the heat conduction between the polymer and the heat source, effectively improving the flame retardancy of the composite material, and significantly improving the glow wire of the material. The compounded CTI additive can make the resin accumulate in a discontinuous form, which helps to improve the leakage tracking index of the material. DETAILED DESCRIPTION

[0019] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. The present invention can be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that this disclosure will be thorough and complete, and the concept of the present invention will be fully conveyed to those skilled in the art, and the present invention will only be limited by the claims.

[0020] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0021] An embodiment of the present invention provides a glass fiber reinforced PA12-PA6T composite material and a preparation method thereof. The composite material includes the following components by weight percentage: 40%-65% PA12 resin, 10%-15% PA6T resin, 10%-20% glass fiber, 10%-20% compound flame retardant, 5%-10% CTI enhancer, 1.5%-5% antioxidant, and 1.5%-5% compatibilizer.

[0022] The glass fiber is a glass fiber with surface treated with silane.

[0023] The compound flame retardant is a flame retardant masterbatch prepared by mixing a modified microencapsulated aluminum hypophosphite flame retardant and an MCA flame retardant in a mass ratio of 2:1.

[0024] The preparation method of the modified microencapsulated aluminum hypophosphite flame retardant is as follows: melamine formaldehyde prepolymer and ammonium polyphosphate in a mass ratio of 1:(2-3) are mixed to obtain a suspension; the suspension is subjected to an in-situ polymerization reaction at a temperature of 100-120°C for 6-12 hours, and then dried to obtain the modified microencapsulated aluminum hypophosphite flame retardant.

[0025] The CTI enhancer is prepared by mixing modified boehmite and zinc borate in a mass ratio of 2:1. The preparation method of the modified boehmite is as follows: weigh a certain mass of boehmite, add phthalate coupling agent diluted with isopropanol accounting for 0.5-2.5% of the mass of the boehmite, stir and mix at high speed and then dry to obtain the modified boehmite.

[0026] The antioxidant is at least one of hindered phenol antioxidants.

[0027] The compatibilizer is at least one of maleic anhydride grafted polypropylene copolymer and maleic anhydride grafted polyethylene copolymer.

[0028] The embodiment of the present invention also provides a method for preparing a glass fiber reinforced PA12-PA6T composite material, comprising the following steps:

[0029] S1: drying the PA12 resin, PA6T resin, glass fiber, compound flame retardant, CTI enhancer, antioxidant and compatibilizer;

[0030] S2: premixing the dried PA12 resin, PA6T resin, compound flame retardant, CTI enhancer, antioxidant and compatibilizer to obtain an initial mixture;

[0031] S3: The initial mixture is put into the main feeder hopper of the twin-screw extruder, and is transported by its own gravity and the main feeder screw. At the same time, the dried glass fiber is added to the side feeder hopper and transported to the screw cavity of the twin-screw extruder through the side feeder screw. After heating, melting, extrusion and granulation by heating the barrel and screw shearing, the composite material of the present invention is obtained.

[0032] Among them, the processing temperature of the twin-screw extruder is controlled at 280-310°C, and the main engine speed is

[0033] 300~350rpm.

[0034] The glass fiber reinforced PA12-PA6T composite material and the preparation method of the present invention will be described in detail below in combination with embodiments, comparative examples and experimental data.

[0035] Sources of components in each embodiment and comparative example:

[0036] PA12 resin: Evonik Group of Germany, PA12 grade, L1940.

[0037] PA6T resin: Qingdao Sanlibennuo New Materials Co., Ltd., polyhexamethylene terephthalamide / caprolactam (1132).

[0038] Glass fiber: Glass fiber treated with surface silane. The glass fiber was purchased from Jushi Group Co., Ltd., model ECS10-03-568H, and the treatment method was as follows: 20 mL of KH550 silane coupling agent was dissolved in 980 mL of anhydrous ethanol to prepare a silane coupling agent solution with a volume fraction of 2%; 10% mass fraction of glass fiber was added to the silane coupling agent solution, stirred at 80-100°C for 4-6h, filtered out, placed in a vacuum drying oven at 80-100°C for drying and cooling, and obtained glass fiber treated with surface silane.

[0039] Compound flame retardant: A flame retardant masterbatch prepared by mixing modified microencapsulated aluminum hypophosphite flame retardant and MCA flame retardant in a mass ratio of 2:1.

[0040] The preparation method of the modified microencapsulated aluminum hypophosphite flame retardant is as follows:

[0041] (1) A certain amount of urea and formaldehyde solution (urea: formaldehyde solution mass ratio 1:3-5) are mixed and stirred until dissolved, and the pH is adjusted to 8-9 with a 10% sodium bicarbonate solution, and the temperature is raised to 70°C for reaction for 1.5 hours to obtain a melamine formaldehyde prepolymer.

[0042] (2) Mixing melamine formaldehyde prepolymer and ammonium polyphosphate in a mass ratio of 1:2 to obtain a suspension.

[0043] (3) The suspension is subjected to an in-situ polymerization reaction at 100° C. for 12 hours and then dried to obtain a modified microencapsulated aluminum hypophosphite flame retardant.

[0044] Among them, urea / formaldehyde solution / ammonium polyphosphate: Sinopharm Chemical Reagent Co., Ltd. MCA flame retardant: Jiangsu Uninode New Materials Co., Ltd., melamine cyanurate.

[0045] CTI enhancer: modified boehmite and zinc borate are mixed in a mass ratio of 2:1. The preparation method of modified boehmite is as follows: weigh a certain mass of boehmite, add phthalate coupling agent diluted with isopropanol accounting for 0.5-2.5% of the mass of boehmite, stir and mix at high speed and then dry to obtain modified boehmite. Boehmite: Weihai Baidexin New Materials Co., Ltd., nano boehmite. Zinc borate: Jiangsu Weiguan New Materials Co., Ltd., anhydrous zinc borate.

[0046] Antioxidant: Antioxidant RIANOX 1010, Tianjin Li'anlong New Materials Co., Ltd.

[0047] Compatibilizer: Maleic anhydride grafted polypropylene copolymer PP-g-MAH, Jiayirong Polymer (Shanghai) Co., Ltd.

[0048] Examples 1-3 and Comparative Examples 1-2

[0049] A method for preparing a glass fiber reinforced PA12-PA6T composite material comprises the following steps:

[0050] (1) Accurately weigh each component;

[0051] The formulas of each embodiment and comparative example are as follows:

[0052] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 PA12 resin 42.5 48 51.5 65 62 PA6T resin 10 10 10 10 10 Fiberglass 20 15 10 20 20 Compound flame retardant 15 17.5 12.5 / / CTI Enhancer 7.5 5.0 10 / 3.0 Antioxidants 2.5 3.0 3.0 2.5 2.5 Compatibilizer 2.5 1.5 3.0 2.5 2.5

[0053] (2) Premixing the PA12 resin and PA6T resin after drying (120° C., 4 h), the compound flame retardant, the CTI enhancer, the antioxidant, and the compatibilizer to obtain an initial mixture;

[0054] (3) The initial mixture is put into the main feeding hopper of the twin-screw extruder, and conveyed by its own gravity and the screw of the first feeding zone of the twin-screw extruder. At the same time, the dried glass fiber is added to the hopper of the side feeder, and conveyed to the screw cavity of the twin-screw extruder by the screw of the side feeder. After heating and melting by heating the barrel and screw shearing, extrusion and granulation, the composite materials of Examples 1-3 and Comparative Examples 1-2 are finally obtained. The processing temperature of the twin-screw extruder is controlled at 280-310°C, and the main engine speed is 300-350rpm.

[0055] The composite materials prepared in Examples 1-3 and Comparative Examples 1-2 were tested for performance, and the test results are shown in the following table:

[0056]

[0057]

[0058] As can be seen from the above table, in Examples 1 to 3 of the present invention, PA12 / PA6T composite materials are developed by different proportions of PA12 resin, PA6T resin, glass fiber, compound flame retardant, CTI enhancer, antioxidant, and compatibilizer. The surface-treated glass fiber plays a reinforcing role and improves the mechanical properties of the composite material; the appropriate amount of compound flame retardant forms a dense carbon layer to block the heat conduction between the polymer and the heat source, effectively improving the flame retardancy of the composite material, enabling the material to pass through 850°C glow wire and improve the resistance to leakage tracking; the boehmite and zinc borate with a flaky structure are compounded in a certain proportion as a CTI enhancer, distributed in the matrix resin, so that the resin is accumulated in a discontinuous form, interrupting the carbonization path, and improving the CTI value of the composite material; the added maleic anhydride graft copolymer compatibilizer can improve the compatibility of the two-phase interface in the alloy, so that the uniform dispersion of glass fiber, flame retardant, and CTI enhancer in the resin is improved, and the impact performance of the material is improved; the antioxidant improves the antioxidant performance of the composition during processing and the anti-aging performance during use. The glass fiber reinforced PA12-PA6T composite material of the present invention has good mechanical properties, good flame retardant properties, high glow wire temperature, high leakage tracking index, balanced mechanical properties and flame retardant properties, and can be used in automotive electrical products requiring high strength, high heat resistance, etc.

[0059] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A glass fiber reinforced PA12-PA6T composite material, characterized in that: Calculated by weight percentage, the composition includes: 40%-65% PA12 resin, 10%-15% PA6T resin, 10%-20% glass fiber, 10%-20% compound flame retardant, 5%-10% CTI enhancer, 1.5%-5% antioxidant and 1.5%-5% compatibilizer.

2. The composite material according to claim 1, characterized in that: The glass fiber is a glass fiber treated with silane on the surface.

3. The composite material according to claim 1, characterized in that: The compound flame retardant is a flame retardant masterbatch prepared by mixing a modified microencapsulated aluminum hypophosphite flame retardant and an MCA flame retardant in a mass ratio of 2:

1.

4. The composite material according to claim 3, characterized in that: The preparation method of the modified microencapsulated aluminum hypophosphite flame retardant is as follows: melamine formaldehyde prepolymer and ammonium polyphosphate are mixed in a mass ratio of 1:(2-3) to obtain a suspension; the suspension is subjected to an in-situ polymerization reaction at a temperature of 100° C. to 120° C. for 6 to 12 hours, and then dried to obtain the modified microencapsulated aluminum hypophosphite flame retardant.

5. The composite material according to claim 1, characterized in that: The CTI enhancer is prepared by mixing modified boehmite and zinc borate in a mass ratio of 2:

1.

6. The composite material according to claim 5, characterized in that: The preparation method of the modified boehmite is as follows: weigh a certain mass of boehmite, add phthalate coupling agent diluted with isopropanol accounting for 0.5-2.5% of the mass of the boehmite, stir and mix at high speed and then dry to obtain the modified boehmite.

7. The composite material according to claim 1, characterized in that: The antioxidant is at least one of hindered phenol antioxidants.

8. The composite material according to claim 1, characterized in that: The compatibilizer is at least one of maleic anhydride grafted polypropylene copolymer and maleic anhydride grafted polyethylene copolymer.

9. The method for preparing the composite material according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: drying the PA12 resin, PA6T resin, glass fiber, compound flame retardant, CTI enhancer, antioxidant and compatibilizer; S2: premixing the dried PA12 resin, PA6T resin, compound flame retardant, CTI enhancer, antioxidant and compatibilizer to obtain an initial mixture; S3: The initial mixture is fed into the main feeder hopper of a twin-screw extruder, and conveyed by its own gravity and the main feeder screw. At the same time, the dried glass fiber is added to the side feeder hopper, and conveyed to the screw cavity of the twin-screw extruder by the side feeder screw. After heating and melting by the heated barrel and screw shearing, and extrusion granulation, the composite material is obtained.

10. The preparation method according to claim 9, characterized in that: The processing temperature of the twin-screw extruder is controlled at 280-310° C., and the main engine speed is 300-350 rpm.

Images