Nylon having excellent heat conductivity and a method for producing the same

Abstract

The present application relates to a kind of nylon with excellent heat conduction performance and preparation method, belong to the technical field of nylon material.The nylon includes: nylon resin, modified heat-conducting filler, compatibilizer, antioxidant and lubricant.The preparation of modified heat-conducting filler includes: taking mixed material is placed in water and is stirred and ultrasonic dispersion, add aluminum nitrate hexahydrate and heat, dry after purification, obtain composite filler;Composite filler and ethanol are stirred and dispersed, add silane coupling agent and stir, dry after purification, obtain intermediate;Intermediate and ethanol are stirred and mixed, add styrene, monomer and initiator and heat stirring, dry after purification, obtain.The present application uses nylon resin as matrix, combines boron nitride, alumina and graphene nanosheet composite and carries out organic modification to it, and uses maleic anhydride grafted polypropylene as compatibilizer, effectively improves the heat conduction performance and comprehensive mechanical property of nylon pipe.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of nylon materials, and relates to a nylon with excellent heat conduction performance and a preparation method. BACKGROUND

[0002] In the category of engineering plastics, nylon resins (such as PA6 and PA66) are widely used due to their excellent mechanical strength, wear resistance, chemical resistance and processing performance. However, the thermal conductivity of pure nylon is relatively low, about 0.2-0.3 W / (m·K), which makes it difficult to meet the requirements of modern industry for high-efficiency heat dissipation of materials.

[0003] The molecular chain of the nylon resin contains strong polar amide groups, while the surface polarity of various heat-conducting fillers is significantly different: for example, the graphene nanosheet is mainly composed of non-polar sp 2 Carbon structure. This difference in polarity leads to insufficient interfacial compatibility between the filler and the nylon matrix, which easily causes uneven dispersion and aggregation of graphene. In addition, due to the lack of chemical bonding between the heat-conducting filler and the nylon, the interfacial bonding force is weak, which not only forms a thermal resistance layer at the interface, hindering the efficiency of heat transfer, but also reduces the mechanical properties of the composite material. At the same time, in the process of mixing multiple heat-conducting fillers, mutual stacking or repulsion may occur due to steric hindrance effects, leading to uneven distribution of fillers and affecting the continuity of the heat-conducting network. The problems of polarity mismatch between the heat-conducting filler and the nylon resin, weak interfacial bonding force, and geometric incompatibility have become the main obstacles to the improvement of the mechanical properties of the composite heat-conducting material and the nylon resin. SUMMARY

[0004] The purpose of the present application is to provide a nylon with excellent heat conduction performance and a preparation method. The present application uses nylon resin as the matrix, combined with boron nitride, aluminum oxide and graphene nanosheet as the composite heat-conducting filler. Boron nitride provides high thermal conductivity and chemical stability, aluminum oxide increases the heat conduction path, and graphene nanosheet significantly enhances the heat conduction effect. This combination effectively improves the heat conduction performance and comprehensive performance of the nylon tube. In addition, maleic anhydride grafted polypropylene is used as a compatibilizer to further improve the compatibility of the filler and the matrix and enhance the mechanical properties of the nylon tube.

[0005] The purpose of the present application can be achieved by the following technical solutions:

[0006] A nylon with excellent heat conduction performance comprises the following components by weight fraction:

[0007] Nylon resin 94-100 parts, modified heat-conducting filler 12-16 parts, compatibilizer 8-10 parts, antioxidant 0.6-1.2 parts, lubricant 0.4-0.6 parts.

[0008] As a preferred technical solution of the present application, the nylon resin is any one or a combination of more than one of nylon 6, nylon 66, nylon 610 and nylon 612; the examples and comparative examples use nylon 610: Hiprolon 70NN, Suzhou HANP High Polymer Material Co., Ltd.

[0009] As a preferred technical solution of the present application, the compatilizer is maleic anhydride grafted polypropylene.

[0010] As a preferred technical solution of the present application, the compatilizer is maleic anhydride grafted polypropylene.

[0011] As a preferred technical solution of the present application, maleic anhydride has greater polarity and contains double bonds in the molecular chain, and has higher reactivity, and is easy to react with polymers containing carboxyl, amine and carbonyl, carbon-carbon double bond and other functional groups.

[0012] As a preferred technical solution of the present application, the antioxidant is any one or a combination of more than one of antioxidant 1010, antioxidant 1076, antioxidant 1098 and antioxidant 168.

[0013] As a preferred technical solution of the present application, the lubricant is any one or a combination of more than one of stearate, polyethylene wax and oxidized polyethylene wax.

[0014] As a preferred technical solution of the present application, the preparation method of the modified heat-conducting filler comprises the following steps:

[0015] S1, the mixed material is placed in deionized water and stirred and ultrasonically dispersed, aluminum nitrate hexahydrate is added and mixed, then ammonia water is added and heated, cooled to room temperature, filtered, the solid is washed with water, placed in an oven and vacuum dried to obtain a composite filler;

[0016] S2, the composite filler and anhydrous ethanol are placed in a reaction kettle and stirred and dispersed, silane coupling agent is added and constant temperature stirring is performed, the solid is taken out by centrifugation and washed with alcohol, placed in an oven and vacuum dried to obtain an intermediate;

[0017] S3, the intermediate and anhydrous ethanol are placed in a reaction kettle and stirred and mixed, styrene, monomer and initiator are added and heated and stirred, the supernatant is removed by centrifugation, washed (for example, alcohol washing), placed in an oven and vacuum dried to obtain a modified heat-conducting filler.

[0018] As a preferred technical solution of the present application, in step S1, the stirring is at a speed of 300-500 r / min for 15-30 min. The ultrasonic dispersion is at a power of 100-120 W for 15-20 min. The heating is at 30-40℃ for 6-8 h. The water washing is with deionized water until the solid surface is neutral. The vacuum drying is at 80-90℃ until constant weight.

[0019] As a preferred technical solution of the present application, in step S1, the mass ratio of the mixed material, deionized water, ammonia water and aluminum nitrate hexahydrate is (18-20):(100-120):(70-80):(8-9). The concentration of the ammonia water is 14-18 wt%. The mixed material consists of graphene oxide and hexagonal boron nitride at a mass ratio of (1.2-1.5):(0.8-1.0).

[0020] As a preferred technical solution of the present application, in step S2, the stirring dispersion is at a speed of 700-1000 r / min for 10-15 min. The constant temperature stirring is at 60-65℃ for 4-5 h. The alcohol washing is with ethanol for 3-4 times. The vacuum drying is at 80-90℃ until constant weight.

[0021] As a preferred technical solution of the present application, in step S2, the mass ratio of the composite filler, anhydrous ethanol and silane coupling agent is (10-14):(40-50):(4.2-5.0). The silane coupling agent is any one or a combination of two of vinyltrimethoxysilane and vinyltriethoxysilane.

[0022] As a preferred technical solution of the present application, in step S3, the stirring mixing is at a speed of 500-800 r / min for 20-30 min. The heating stirring is at 60-70℃ for 4-6 h. The alcohol washing is with ethanol for 3 times. The vacuum drying is at 80-90℃ until constant weight.

[0023] As a preferred technical solution of the present application, in step S3, the mass ratio of the intermediate, anhydrous ethanol, styrene, monomer and initiator is (12-15):(50-60):(1.2-1.5):(0.8-0.9):(0.07-0.09). The monomer is any one or a combination of two of acrylic acid and methacrylic acid. The initiator is an azo compound. In the examples and comparative examples of the present application, the initiator uses initiator AIBN.

[0024] This invention discloses a method for preparing nylon with excellent thermal conductivity, comprising the following steps: mixing nylon resin, modified thermally conductive filler, compatibilizer, antioxidant and lubricant in an intensive kneading process, extruding in a twin-screw extruder, cooling and pelletizing to obtain the nylon.

[0025] The beneficial effects of this invention are:

[0026] This invention uses nylon resin as the matrix and creatively employs a composite thermally conductive filler system of boron nitride, alumina, and graphene nanosheets. Boron nitride ensures good thermal conductivity and chemical stability, alumina filler increases thermal conductivity pathways, and graphene nanosheets enhance thermal conductivity with their extremely high thermal conductivity. The combination of these three components significantly improves thermal conductivity and enhances the overall performance of the nylon tube. Maleic anhydride-grafted polypropylene is used as a compatibilizer to improve the compatibility between the filler and the matrix, thereby improving the mechanical properties of the nylon tube. Compared with existing nylon tube technologies, this invention has significant advantages in improving thermal conductivity and optimizing overall material performance, and is expected to provide high-performance thermally conductive pipe solutions for related fields. Detailed Implementation

[0027] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following detailed description of the specific implementation methods, structures, features and effects of the present invention, in conjunction with embodiments, is provided below.

[0028] Maleic anhydride-grafted polypropylene, model 18722, Arkema, France.

[0029] Polyethylene wax, polymer grade polyethylene wax, CRALENE, Euroceras GmbH, Germany.

[0030] Example 1

[0031] A nylon with excellent thermal conductivity comprises the following components in parts by weight:

[0032] The mixture contains 94 parts nylon resin, 12 parts modified thermally conductive filler, 8 parts compatibilizer, 0.6 parts antioxidant, and 0.4 parts lubricant.

[0033] The nylon resin is nylon 610; the compatibilizer is maleic anhydride-grafted polypropylene; the antioxidant is antioxidant 1010; and the lubricant is polyethylene wax.

[0034] The preparation method of the modified thermally conductive filler includes the following steps:

[0035] S1. The mixed material is placed in deionized water and stirred at 300 r / min for 15 min, then sonicated at 100 W for 15 min. Aluminum nitrate hexahydrate is added and mixed, followed by ammonia water. The mixture is heated at 30℃ for 6 h, cooled to room temperature, and filtered. The solid is washed with deionized water until the surface is neutral, placed in an oven, and vacuum dried at 80℃ to constant weight to obtain the composite filler. The mass ratio of the mixed material, deionized water, ammonia water, and aluminum nitrate hexahydrate is 18:100:70:8; the concentration of the ammonia water is 14 wt%; the mixed material is composed of graphene oxide and hexagonal boron nitride in a mass ratio of 1.2:0.8.

[0036] S2. Place the composite filler and anhydrous ethanol in a reaction vessel, stir at 700 r / min for 10 min, add silane coupling agent, heat to 60℃ and stir for 4 h, centrifuge, take the solid, wash 3 times with ethanol, place in an oven, and vacuum dry at 80℃ to constant weight to obtain an intermediate; the mass ratio of the composite filler, anhydrous ethanol and silane coupling agent is 10:40:4.2; the silane coupling agent is vinyltrimethoxysilane;

[0037] S3. The intermediate and anhydrous ethanol were placed in a reaction vessel and stirred at 500 r / min for 20 min. Styrene, monomer and initiator were added and stirred at 60℃ for 4 h. After centrifugation to remove the supernatant, the mixture was washed three times with ethanol and placed in an oven to be vacuum dried at 80℃ to constant weight to obtain the modified thermally conductive filler. The mass ratio of the intermediate, anhydrous ethanol, styrene, monomer and initiator was 12:50:1.2:0.8:0.07. The monomer was acrylic acid.

[0038] A method for preparing nylon with excellent thermal conductivity includes the following steps: mixing nylon resin, modified thermally conductive filler, compatibilizer, antioxidant and lubricant in an intensive kneading process and then melt-extruding the mixture in a twin-screw extruder. During extrusion, the temperatures of heating zones 1 to 10 and the die head are 220℃, 260℃, 260℃, 260℃, 260℃, 255℃, 250℃, 250℃, 250℃, and 250℃ respectively. The mixture is then cooled and pelletized to obtain the final product.

[0039] Example 2

[0040] A nylon with excellent thermal conductivity comprises the following components in parts by weight:

[0041] The mixture contains 97 parts nylon resin, 14 parts modified thermally conductive filler, 9 parts compatibilizer, 0.9 parts antioxidant, and 0.5 parts lubricant.

[0042] The nylon resin is nylon 610; the compatibilizer is maleic anhydride-grafted polypropylene; the antioxidant is antioxidant 1010; and the lubricant is polyethylene wax.

[0043] The preparation method of the modified thermally conductive filler includes the following steps:

[0044] S1. The mixed material was placed in deionized water and stirred at 400 r / min for 22 min, then sonicated at 110 W for 18 min. Aluminum nitrate hexahydrate was added and mixed, followed by ammonia water. The mixture was heated at 35℃ for 7 h, cooled to room temperature, and filtered. The solid was washed with deionized water until the surface was neutral, placed in an oven, and vacuum dried at 85℃ to constant weight to obtain the composite filler. The mass ratio of the mixed material, deionized water, ammonia water, and aluminum nitrate hexahydrate was 19:110:75:8.5; the concentration of the ammonia water was 16 wt%; the mixed material was composed of graphene oxide and hexagonal boron nitride in a mass ratio of 1.4:0.9.

[0045] S2. The composite filler and anhydrous ethanol are placed in a reaction vessel and stirred at 850 r / min for 12 min. A silane coupling agent is added, and the mixture is heated to 62℃ and stirred for 4.5 h. The solid is centrifuged, washed three times with ethanol, placed in an oven, and vacuum dried at 85℃ to constant weight to obtain an intermediate. The mass ratio of the composite filler, anhydrous ethanol, and silane coupling agent is 12:45:4.6. The silane coupling agent is vinyltrimethoxysilane.

[0046] S3. The intermediate and anhydrous ethanol were placed in a reaction vessel and stirred at 650 r / min for 25 min. Styrene, monomer and initiator were added and stirred at 65℃ for 5 h. After centrifugation to remove the supernatant, the mixture was washed three times with ethanol and placed in an oven to be vacuum dried at 85℃ to constant weight to obtain the modified thermally conductive filler. The mass ratio of the intermediate, anhydrous ethanol, styrene, monomer and initiator was 14:55:1.4:0.85:0.08. The monomer was acrylic acid.

[0047] A method for preparing nylon with excellent thermal conductivity includes the following steps: mixing nylon resin, modified thermally conductive filler, compatibilizer, antioxidant and lubricant in an intensive kneading process and then melt-extruding the mixture in a twin-screw extruder. During extrusion, the temperatures of heating zones 1 to 10 and the die head are 220℃, 260℃, 260℃, 260℃, 260℃, 255℃, 250℃, 250℃, 250℃, and 250℃ respectively. The mixture is then cooled and pelletized to obtain the final product.

[0048] Example 3

[0049] A nylon with excellent thermal conductivity comprises the following components in parts by weight:

[0050] 100 parts nylon resin, 16 parts modified thermally conductive filler, 10 parts compatibilizer, 1.2 parts antioxidant, and 0.6 parts lubricant;

[0051] The nylon resin is nylon 610; the compatibilizer is maleic anhydride-grafted polypropylene; the antioxidant is antioxidant 1010; and the lubricant is polyethylene wax.

[0052] The preparation method of the modified thermally conductive filler includes the following steps:

[0053] S1. The mixed material is placed in deionized water and stirred at 500 r / min for 30 min, then sonicated at 120 W for 20 min. Aluminum nitrate hexahydrate is added and mixed, followed by ammonia water. The mixture is heated at 40℃ for 8 h, cooled to room temperature, and filtered. The solid is washed with deionized water until the surface is neutral, placed in an oven, and vacuum dried at 90℃ to constant weight to obtain the composite filler. The mass ratio of the mixed material, deionized water, ammonia water, and aluminum nitrate hexahydrate is 20:120:80:9; the concentration of the ammonia water is 18 wt%; the mixed material is composed of graphene oxide and hexagonal boron nitride in a mass ratio of 1.5:1.0.

[0054] S2. Place the composite filler and anhydrous ethanol in a reaction vessel, stir at 1000 r / min for 15 min, add silane coupling agent, heat to 65℃ and stir for 5 h, centrifuge, take the solid, wash 4 times with ethanol, place in an oven, and vacuum dry at 90℃ to constant weight to obtain an intermediate; the mass ratio of the composite filler, anhydrous ethanol and silane coupling agent is 14:50:5.0; the silane coupling agent is vinyltrimethoxysilane;

[0055] S3. The intermediate and anhydrous ethanol were placed in a reaction vessel and stirred at 800 r / min for 30 min. Styrene, monomer and initiator were added and stirred at 70℃ for 6 h. After centrifugation to remove the supernatant, the mixture was washed three times with ethanol and placed in an oven to be vacuum dried at 90℃ to constant weight to obtain the modified thermally conductive filler. The mass ratio of the intermediate, anhydrous ethanol, styrene, monomer and initiator was 15:60:1.5:0.9:0.09. The monomer was acrylic acid.

[0056] A method for preparing nylon with excellent thermal conductivity includes the following steps: mixing nylon resin, modified thermally conductive filler, compatibilizer, antioxidant and lubricant in an intensive kneading process and then melt-extruding the mixture in a twin-screw extruder. During extrusion, the temperatures of heating zones 1 to 10 and the die head are 220℃, 260℃, 260℃, 260℃, 260℃, 255℃, 250℃, 250℃, 250℃, and 250℃ respectively. The mixture is then cooled and pelletized to obtain the final product.

[0057] Example 4

[0058] Compared with Example 3, Example 4 differs in that the monomer in step S3 is composed of acrylic acid and methacrylic acid in a 1:1 ratio; all other aspects are the same.

[0059] Comparative Example 1

[0060] Compared with Example 3, Comparative Example 1 differs in step S1;

[0061] Step S1: After mixing deionized water and aluminum nitrate hexahydrate, ammonia water is added and the mixture is heated at 40°C for 8 hours. The mixture is then stirred at 500 r / min for 30 minutes and ultrasonicated at 120 W for 20 minutes. After cooling to room temperature, the mixture is filtered. The solid is washed with deionized water until the surface is neutral. The solid is then placed in an oven and vacuum dried at 90°C to constant weight to obtain the composite filler. The mass ratio of the mixture, deionized water, ammonia water, and aluminum nitrate hexahydrate is 20:120:80:9. The concentration of the ammonia water is 18 wt%. The mixture is composed of graphene oxide and hexagonal boron nitride in a mass ratio of 1.5:1.0.

[0062] Everything else is the same.

[0063] Comparative Example 2

[0064] Compared with Example 3, Comparative Example 2 differs in that it does not use a silane coupling agent, but is otherwise identical.

[0065] Comparative Example 3

[0066] Compared with Example 3, Comparative Example 2 differs in that styrene is used instead of the monomer, while all other aspects are the same.

[0067] Comparative Example 4

[0068] Compared with Example 3, Comparative Example 2 differs in that no compatibilizer is added, but all other aspects are the same.

[0069] The nylon materials prepared in Examples 1-4 and Comparative Examples 1-4 were subjected to performance tests. The impact strength test was conducted according to ASTM D256, and the thermal conductivity test was conducted according to ASTM E1461.

[0070] Table 1 Performance Test Results

[0071] Impact strength (KJ / m 2 )]]> Thermal conductivity (W / MK) Example 1 9.9 1.79 Example 2 9.7 1.82 Example 3 10.2 1.88 Example 4 9.5 1.86 Comparative Example 1 8.8 1.32 Comparative Example 2 9.1 1.54 Comparative Example 3 8.7 1.61 Comparative Example 4 6.4 1.25

[0072] As can be seen from the test results in Table 1, compared with Comparative Examples 1-4, the present invention uses acrylic acid / methacrylic acid and styrene as coating modified thermally conductive fillers, which can significantly enhance the thermal conductivity and mechanical strength of composite nylon materials.

[0073] The comparison results of Examples 1-4 and Comparative Examples 1-4 in Table 1 show that the compatibilizer used in this invention can not only graft with the carboxyl groups of the modified thermally conductive filler, but also form chemical grafts with nylon resin. The in-situ generation of alumina on graphene / boron nitride can reduce particle accumulation and increase dispersibility. The vinyl groups in the silane coupling agent can increase the organic coating rate, while the carboxyl groups present in acrylic acid / methacrylic acid can improve the compatibility between the thermally conductive filler and nylon resin through hydrogen bonding. This is beneficial to promoting good dispersion of the modified thermally conductive filler in the nylon substrate and improving the thermal conductivity and mechanical strength of the composite nylon material.

[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any indirect modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A nylon with excellent thermal conductivity, characterized in that, The composition by weight is as follows: 94-100 parts nylon resin, 12-16 parts modified thermally conductive filler, 8-10 parts compatibilizer, 0.6-1.2 parts antioxidant, and 0.4-0.6 parts lubricant; The preparation method of modified thermally conductive filler includes the following steps: S1. Take the mixed material, stir and ultrasonically disperse it in water, add aluminum nitrate hexahydrate, mix well, then add ammonia water and heat, cool and filter, take the solid, wash and dry it to obtain the composite filler; wherein, the mixed material includes graphene oxide and hexagonal boron nitride; S2. Stir and disperse the composite filler and ethanol, add silane coupling agent and stir, centrifuge to collect the solid, wash and dry to obtain the intermediate; S3. Mix the intermediate and ethanol, add styrene, monomer and initiator, heat and stir, centrifuge to remove the supernatant, wash and dry to obtain the modified thermally conductive filler. The monomer is any one or a combination of two of acrylic acid and methacrylic acid.

2. The nylon with excellent thermal conductivity according to claim 1, characterized in that: The nylon resin is any one or a combination of nylon 6, nylon 66, nylon 610 and nylon 612; the compatibilizer is maleic anhydride-grafted polypropylene.

3. The nylon with excellent thermal conductivity according to claim 1, characterized in that: The antioxidant is any one or more of antioxidant 1010, antioxidant 1076, antioxidant 1098 and antioxidant 168; the lubricant is any one or more of stearate, polyethylene wax and oxidized polyethylene wax.

4. The nylon with excellent thermal conductivity according to claim 1, characterized in that: In step S1, the stirring is performed at a rate of 300-500 r / min for 15-30 min; the ultrasonic dispersion is performed at a power of 100-120 W for 15-20 min.

5. The nylon with excellent thermal conductivity according to claim 1, characterized in that: In step S1, the mass ratio of the mixed material, deionized water, ammonia water and aluminum nitrate hexahydrate is (18-20):(100-120):(70-80):(8-9); the concentration of the ammonia water is 14-18 wt%; the mixed material is composed of graphene oxide and hexagonal boron nitride in a mass ratio of (1.2-1.5):(0.8-1.0).

6. The nylon with excellent thermal conductivity according to claim 1, characterized in that: In step S2, the stirring and dispersion is carried out by stirring at a speed of 700-1000 r / min for 10-15 min; the addition of silane coupling agent and stirring is carried out by heating to 60-65℃ and stirring for 4-5 h.

7. The nylon with excellent thermal conductivity according to claim 1, characterized in that: In step S2, the mass ratio of the composite filler, ethanol and silane coupling agent is (10-14):(40-50):(4.2-5.0); the silane coupling agent is any one or a combination of two of vinyltrimethoxysilane and vinyltriethoxysilane.

8. The nylon with excellent thermal conductivity according to claim 1, characterized in that: In step S3, the stirring and mixing is carried out at a speed of 500-800 r / min for 20-30 min; the heating and stirring is carried out at 60-70℃ for 4-6 h; and the drying is carried out under vacuum at 80-90℃ until constant weight.

9. A nylon with excellent thermal conductivity according to claim 1, characterized in that: In step S3, the mass ratio of the intermediate, ethanol, styrene, monomer and initiator is (12-15):(50-60):(1.2-1.5):(0.8-0.9):(0.07-0.09).

10. A method for preparing nylon with excellent thermal conductivity as described in any one of claims 1 to 9, characterized in that, The preparation method includes the following steps: mixing nylon resin, modified thermally conductive filler, compatibilizer, antioxidant and lubricant in an intensive kneading process, extruding, cooling and pelletizing the mixture in a twin-screw extruder to obtain the final product.