Basalt-reinforced halogen-free flame-retardant PA66MXD6 composite material and preparation method thereof

Abstract

The invention discloses a basalt reinforced halogen-free flame retardant PA66MXD6 composite material and a preparation method thereof, the composite material comprises the following components by weight: 25%-50% of PA66 resin, 20%-40% of MXD6 resin, 25%-40% of modified basalt fiber, 15%-20% of a compound flame retardant, 0.5%-5% of a flexibilizer, and 0.5%-2% of a lubricant. The composite material disclosed by the invention has the advantages of good mechanical property, good flame retardant property and balanced mechanical property and flame retardant property, and can be used in automobile electronic and electrical products with high-strength, halogen-free and flame-retardant requirements.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a basalt reinforced halogen-free flame-retardant PA66MXD6 composite material and a preparation method thereof. Background Art

[0002] With the increasing application of nylon materials in new energy vehicles, especially in electronic and electrical products, higher requirements are placed on the mechanical properties and flame retardant properties of the materials. PA66 is an important variety of polyamide materials, with the characteristics of toughness, wear resistance, self-lubrication, and a wide operating temperature range. MXD6 (poly(m-phenylenediamine adipamide)) is a crystalline semi-aromatic special nylon resin that can maintain high strength and high rigidity performance characteristics in a wide temperature range. It has a low water absorption rate among nylon materials, small dimensional changes after water absorption, and less reduction in mechanical strength.

[0003] In order to meet the needs of electronic and electrical products, the PA66 / MXD6 composite material prepared combines the mechanical properties of PA66 materials and the high rigidity, high modulus and excellent barrier properties of MXD6 materials. Although it has good comprehensive performance, it still needs to be enhanced, flame retardant and other modifications to meet the needs of electronic and electrical products in different fields for high strength and high flame retardancy of materials. Summary of the invention

[0004] Based on the deficiencies in the prior art, the purpose of the present invention is to provide a basalt reinforced halogen-free flame-retardant PA66MXD6 composite material and a preparation method thereof. The composite material has good mechanical properties, good flame retardant properties, and balanced mechanical properties and flame retardant properties, and can be used in automotive electronic and electrical product series that require high strength and halogen-free flame retardancy.

[0005] In order to achieve the above purpose, this application adopts the following technical solutions:

[0006] In the first aspect, the present invention provides a basalt reinforced halogen-free flame retardant PA66MXD6 composite material, which includes the following components by weight percentage: 25%-50% PA66 resin, 20%-40% MXD6 resin, 25%-40% modified basalt fiber, 15%-20% compound flame retardant, 0.5%-5% toughening agent, and 0.5%-2% lubricant.

[0007] In the above technical solution, the modified basalt fiber is a surface-treated continuous basalt fiber.

[0008] In the above technical scheme, the preparation method of the modified basalt fiber is: adding a certain amount of basalt fiber to an anhydrous ethanol solution of a certain concentration, stirring, ultrasonicating, filtering, and drying; adding the dried basalt fiber to an ethanol-water mixed solution containing a phthalate coupling agent, stirring and reacting at 80-100° C., filtering, separating, and drying to obtain the modified basalt fiber.

[0009] In the above technical solution, the compound flame retardant is a flame retardant masterbatch prepared by mixing a modified microencapsulated aluminum hypophosphite flame retardant and a zinc stannate flame retardant in a mass ratio of 2:1.

[0010] 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, and drying after the reaction to obtain the modified microencapsulated aluminum hypophosphite flame retardant.

[0011] In the above technical solution, the toughening agent is a toughening agent masterbatch prepared by mixing maleic anhydride modified polyolefin elastomer and nano titanium dioxide in a mass ratio of 2:1 and extruding the mixture through a screw.

[0012] In the above technical solution, the lubricant is pentaerythritol tetrastearate.

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

[0014] S1: drying the PA66 resin, MXD6 resin, modified basalt fiber, compound flame retardant, toughening agent and lubricant;

[0015] S2: premixing the dried PA66 resin, MXD6 resin, toughening agent and lubricant to obtain an initial mixture;

[0016] S3: The initial mixture is put into the main feeder hopper of a twin-screw extruder, and is transported by its own gravity and the main feeder screw. At the same time, the dried modified basalt fiber and the compound flame retardant are added to the side feeder hopper, and are transported to the screw cavity of the twin-screw extruder through the side feeder screw. After heating and melting by the heating 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 245-265° C., and the main engine speed is 300-350 rpm.

[0018] The beneficial effects of the present invention are as follows: the present invention couples and modifies the surface of basalt fiber, and the reinforcing agent can enhance and modify the PA66 / MXD6 composite material. The surface-coupled modified basalt fiber can be evenly dispersed in the PA66 / MXD6 resin, and has good interface compatibility with the resin, so that the mechanical properties of the PA66 / MXD6 composite material are greatly 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. After the flame retardant is compounded, the small amount of addition also reduces the effect of the flame retardant on the mechanical properties. The toughening agent masterbatch compounded with maleic anhydride modified polyolefin elastomer and nano titanium dioxide has good compatibility with the matrix resin, and has a better toughness modification effect when added to the PA66 / MXD6 system. At the same time, the added lubricant can also make the fiber and the flame retardant evenly dispersed in the matrix, effectively improving the mechanical properties and flame retardant properties of the composite 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] The present invention provides a basalt reinforced halogen-free flame-retardant PA66MXD6 composite material, which comprises the following components by weight percentage: 25%-50% of PA66 resin, 20%-40% of MXD6 resin, 25%-40% of modified basalt fiber, 15%-20% of compound flame retardant, 0.5%-5% of toughening agent, and 0.5%-2% of lubricant.

[0022] The modified basalt fiber is a surface-treated continuous basalt fiber, and the preparation method is as follows: adding a certain amount of basalt fiber to an anhydrous ethanol solution of a certain concentration, stirring, ultrasonicating, filtering, and drying; adding the dried basalt fiber to an ethanol-water mixed solution containing a phthalate coupling agent, stirring and reacting at 80-100° C., filtering, separating, and drying, so as to obtain the modified basalt fiber.

[0023] As one embodiment, the preparation method of modified basalt fiber is as follows: adding a certain amount of basalt fiber to an anhydrous ethanol solution of a certain concentration, stirring at room temperature for 4-8 hours, ultrasonicating, filtering, and drying for standby use. Adding the dried basalt fiber to an ethanol-water mixed solution containing a phthalate coupling agent, stirring at 80°C for 4-8 hours, filtering, separating, and drying in a vacuum oven at 80°C for 12 hours to obtain the modified basalt fiber.

[0024] The compound flame retardant is a flame retardant masterbatch prepared by mixing a modified microencapsulated aluminum hypophosphite flame retardant and a zinc stannate flame retardant in a mass ratio of 2:1. The preparation method of the modified microencapsulated aluminum hypophosphite flame retardant is as follows: a 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°C to 120°C, and dried after the reaction is completed, thereby obtaining the modified microencapsulated aluminum hypophosphite flame retardant.

[0025] As one of the embodiments, 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 to 3) are mixed 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 placed in a 100°C oven for drying to obtain the modified microencapsulated aluminum hypophosphite flame retardant.

[0026] The toughening agent is a toughening agent masterbatch prepared by mixing maleic anhydride modified polyolefin elastomer and nano titanium dioxide in a mass ratio of 2:1 and extruding the mixture through a screw.

[0027] The lubricant is pentaerythritol tetrastearate.

[0028] The present invention also provides a method for preparing a basalt reinforced halogen-free flame-retardant PA66MXD6 composite material, comprising the following steps:

[0029] S1: drying the PA66 resin, MXD6 resin, modified basalt fiber, compound flame retardant, toughening agent and lubricant (100° C., 4 h);

[0030] S2: premixing the dried PA66 resin, MXD6 resin, toughening agent and lubricant 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 modified basalt fiber and the compound flame retardant are added to the side feeder hopper, and are transported to the screw cavity of the twin-screw extruder by 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 245-265°C, and the main engine speed is 300-350rpm.

[0033] The basalt reinforced halogen-free flame-retardant PA66 / MXD6 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.

[0034] Examples 1-3 and Comparative Examples 1-3

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

[0036] PA66 resin: Pingdingshan Engineering Plastics Co., Ltd., EPR27.

[0037] MXD6 resin: Sinochem Plastics Co., Ltd., ZYMX-5001.

[0038] Modified basalt fiber: Modified basalt fiber is a surface-treated continuous basalt fiber. The preparation method is as follows: add basalt fiber to anhydrous ethanol solution (basalt fiber 10-20wt%), stir at room temperature for 8h, ultrasonicate and filter, and dry for standby use. Add the dried basalt fiber to an ethanol-water mixed solution (volume ratio 9:1) containing 2wt% phthalate coupling agent, stir and react at 80℃ for 8h, filter, separate, and dry in a vacuum oven at 80℃ for 12h to obtain modified basalt fiber. Phthalate coupling agent: NDZ-201 Nanjing Daoning Chemical Co., Ltd.

[0039] Ordinary basalt fiber: Jiangsu Tianlong Basalt Continuous Fiber Co., Ltd., basalt fiber chopped yarn.

[0040] Compound flame retardant: A flame retardant masterbatch prepared by mixing modified microencapsulated aluminum hypophosphite flame retardant and zinc stannate flame retardant in a mass ratio of 2:1.

[0041] The preparation method of the modified microencapsulated aluminum hypophosphite flame retardant is as follows:

[0042] (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.

[0043] (2) Mixing melamine formaldehyde prepolymer and ammonium polyphosphate in a mass ratio of 1:2 to obtain a suspension.

[0044] (3) The suspension is subjected to an in-situ polymerization reaction at 100° C. for 12 hours, and then placed in an oven at 100° C. for drying to obtain a modified microencapsulated aluminum hypophosphite flame retardant.

[0045] Among them, urea / formaldehyde solution / ammonium polyphosphate: Sinopharm Chemical Reagent Co., Ltd. Zinc stannate flame retardant: Wujiang Runtai Fine Chemical Co., Ltd.

[0046] Toughening agent: Maleic anhydride modified polyolefin elastomer and nano titanium dioxide are mixed in a mass ratio of 2:1 and extruded by screw to make toughening agent masterbatch. Among them, maleic anhydride modified polyolefin elastomer: Jiayirong Polymer (Shanghai) Co., Ltd., maleic anhydride grafted ethylene octene copolymer POE-g-MAH. Nano titanium dioxide: DuPont R-103.

[0047] Lubricant: Pentaerythritol stearate, Lonza Chemical Co., Ltd., PETS.

[0048] The preparation method of the composite materials of Examples 1-3 and Comparative Examples 1-4 comprises the following steps:

[0049] (1) Accurately weigh each component;

[0050] The formulas of each embodiment and comparative example are as follows:

[0051]

[0052]

[0053] (2) premixing the PA66 resin and MXD6 resin after drying (100° C., 4 h), a toughening agent, and a lubricant to obtain an initial mixture;

[0054] (3) The initial mixed material is put into the main feeding hopper of the twin-screw extruder, and is transported by its own gravity and the screw of the first feeding zone of the twin-screw extruder. At the same time, the treated modified basalt fiber and the compounded flame retardant masterbatch are added to the hopper of the side feeder, and are transported to the screw cavity of the twin-screw extruder through 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 1-4 are finally obtained. The processing temperature of the twin-screw extruder is controlled at 245-265°C, and the main engine speed is 300-350rpm.

[0055] The materials obtained in Examples 1-3 and Comparative Examples 1-4 were tested for performance, and the test results are shown in the following table:

[0056]

[0057] As can be seen from the above table, in Examples 1 to 3 of the present invention, basalt-reinforced halogen-free flame-retardant PA66 / MXD6 composite materials are developed by using different proportions of PA66 resin, MXD6 resin, modified basalt fiber, compounded flame retardant, toughening agent, and lubricant. Basalt fiber is an inorganic, environmentally friendly, green, high-performance fiber material with the characteristics of high elastic modulus, high tensile strength, high wear resistance, excellent high temperature resistance, and acid and alkali resistance. After the basalt fiber is modified by a phthalate coupling agent, the surface structure of the fiber can be effectively improved. The surface of the modified basalt is connected with an oleophilic group, which improves its compatibility with the PA66 / MXD6 polymer, thereby playing a reinforcing role and improving the rigidity of the composite material. The dense carbon layer formed by the modified microencapsulated aluminum hypophosphite flame retardant and the zinc stannate flame retardant can block the heat conduction between the polymer and the heat source, effectively improving the flame retardancy of the composite material. The compounded flame retardant can also reduce the overall addition amount of the flame retardant and reduce the negative impact of the flame retardant on the mechanical properties and electrical properties of the material. The compounded toughening agent can have very good compatibility with PA66 / MXD6, and can be added to nylon to exert a better toughness modification effect, slowing down the strength decline of the PA66 / MXD6 system. The added compatibilizer can also improve the compatibility of the two-phase interface in the alloy, thereby improving the uniform dispersion of basalt fiber and flame retardant in the resin and improving the impact performance of the material. The basalt reinforced halogen-free flame-retardant PA66 / MXD6 composite material of the present invention has good mechanical properties, good flame retardant properties, and balanced mechanical properties and flame retardant properties, and can be used in automotive electronic and electrical product series that require high strength and halogen-free flame retardancy.

[0058] 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 basalt reinforced halogen-free flame-retardant PA66MXD6 composite material, characterized by: Calculated by weight percentage, the composition includes: 25%-50% PA66 resin, 20%-40% MXD6 resin, 25%-40% modified basalt fiber, 15%-20% compound flame retardant, 0.5%-5% toughening agent, and 0.5%-2% lubricant.

2. The composite material according to claim 1, characterized in that: The modified basalt fiber is a surface-treated continuous basalt fiber.

3. The composite material according to claim 1, characterized in that: The preparation method of the modified basalt fiber is as follows: adding a certain amount of basalt fiber to an anhydrous ethanol solution of a certain concentration, stirring, ultrasonicating, filtering, and drying; adding the dried basalt fiber to an ethanol-water mixed solution containing a phthalate coupling agent, stirring and reacting at 80-100° C., filtering, separating, and drying to obtain the modified basalt fiber.

4. 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 a zinc stannate flame retardant in a mass ratio of 2:

1.

5. The composite material according to claim 4, 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., and dried after the reaction is completed, so as to obtain the modified microencapsulated aluminum hypophosphite flame retardant.

6. The composite material according to claim 1, characterized in that: The toughening agent is a toughening agent masterbatch prepared by mixing maleic anhydride modified polyolefin elastomer and nano titanium dioxide in a mass ratio of 2:1 and extruding the mixture through a screw.

7. The composite material according to claim 1, characterized in that: The lubricant is pentaerythritol tetrastearate.

8. The method for preparing the composite material according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: drying the PA66 resin, MXD6 resin, modified basalt fiber, compound flame retardant, toughening agent and lubricant; S2: premixing the dried PA66 resin, MXD6 resin, toughening agent and lubricant to obtain an initial mixture; S3: The initial mixture is put into the main feeder hopper of a twin-screw extruder, and is transported by its own gravity and the main feeder screw. At the same time, the dried modified basalt fiber and the compound flame retardant are added to the side feeder hopper, and are transported to the screw cavity of the twin-screw extruder through the side feeder screw. After heating and melting by the heating barrel and screw shearing, and extrusion granulation, the composite material is obtained.

9. The preparation method according to claim 8, characterized in that: The processing temperature of the twin-screw extruder is controlled at 245-265° C., and the main engine speed is 300-350 rpm.

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