CN117004216A

CN117004216A - A glass fiber reinforced thermally conductive polyamide composite material and its preparation method and application

Info

Publication number: CN117004216A
Application number: CN202210451024.3A
Authority: CN
Inventors: 黄逸伦; 王宇韬; 李长金; 高达利; 张师军; 吴长江; 尹华; 杨庆泉; 邵静波
Original assignee: Sinopec Beijing Chemical Research Institute Co ltd; China Petroleum and Chemical Corp
Current assignee: Sinopec Beijing Chemical Research Institute Co ltd; China Petroleum and Chemical Corp
Priority date: 2022-04-27
Filing date: 2022-04-27
Publication date: 2023-11-07

Abstract

The invention relates to a glass fiber reinforced thermally conductive polyamide composite material in the field of polymer composite materials and its preparation method and application. The glass fiber reinforced thermally conductive polyamide composite material, based on 100% of the weight of the composite material, contains the following components in weight percentage: polyamide resin 20-50%, glass fiber 10-50%, composite thermally conductive filler 30- 60%; the glass fiber reinforced thermally conductive polyamide composite material has excellent thermal conductivity, mechanical properties and flame retardant properties, low production cost, and is suitable for large-scale production.

Description

Glass fiber reinforced heat-conducting polyamide composite material and preparation method and application thereof

Technical Field

The invention relates to the field of polymer composite materials, in particular to a glass fiber reinforced heat conduction polyamide composite material, a preparation method and application thereof.

Background

With the rapid development of the consumer electronics industry, the integration level and performance of electronic components are higher and higher, and the heating value is also higher and higher, which promotes the demand for novel functional heat conducting materials. The heat conducting polymer composite material has wide application in the fields of circuit packaging, consumer electronics, LED lighting, communication equipment, energy storage, aerospace and the like, and compared with a heat conducting metal material and an inorganic nonmetallic material, the heat conducting polymer composite material has the advantages of low density, easiness in processing and forming, low price, good corrosion resistance, easiness in recycling and the like, so that the heat conducting polymer composite material is accepted by markets and consumers more and more, and particularly in the fields of consumer electronics, LED lighting, communication equipment shells and the like. Taking a mobile phone shell as an example, along with the great improvement of the performance of the mobile phone, the heating condition of electronic components in the mobile phone is more and more serious, and the mobile phone shell is required to rapidly radiate the internal heat, so that a heat conducting material is required; meanwhile, the high-performance mobile phone also needs to give consideration to the communication signal and the wireless charging function, and the metal material can influence the signal and the wireless charging function, so that the heat-conducting polymer composite material becomes a choice of a proper mobile phone shell material. As an electronic product shell material, excellent mechanical properties and flame retardant properties are required to be combined to realize more application scenes and better use effects.

Polyamide, also called nylon, is a thermoplastic polymer material containing amide groups on the molecular main chain, has excellent mechanical properties, processability, wear resistance, corrosion resistance and heat resistance, is nontoxic and recyclable, and is widely applied to various industries. However, the polyamide material itself has a low thermal conductivity of only 0.2 to 0.3. 0.3W m ^-1 K ^-1 It is not suitable for the casing of devices requiring high heat dissipation capability such as LED lighting and mobile phones. Chinese patent CN104140670a discloses a nylon composite material with high thermal conductivity and its preparation method, the composite material is composed of 40-80 parts nylon, 10-60 parts thermal conductive filler (expanded graphite) and 0-6 parts reinforcing filler (mesophase pitch), but the thermal conductive filler needs to be calcined at 500-950 ℃ and has complex process and high energy consumption, and the obtained nylon composite material has poor mechanical properties and tensile strength of only 49.7-66.3 MPa. Chinese patent CN108003607B discloses a flame-retardant heat-conducting nylon composite material and a preparation method thereof, wherein the composite material is prepared from 90-150 parts of nylon-6, 30-60 parts of heat-conducting filler, 10-15 parts of glass fiber, 30-70 parts of porcelain-forming filler, 0.2-0.5 part of coupling agent and 0.1-0.2 part of antioxidant, when an external fire disaster occurs, a ceramic polymer can be converted into a ceramic body with a compact structure, so that the external flame is prevented from invading to cause the combustion of internal materials, but the ceramic body has larger brittleness and does not have good mechanical property.

In the prior art, the heat-conducting polyamide composite material can be obtained by adding the heat-conducting filler, but the preparation of the composite material is difficult due to the limitation of the property of the filler, and the heat-conducting property, the mechanical property and the flame retardant property are difficult to balance, so that the heat-conducting polyamide composite material with excellent heat-conducting property, mechanical property and flame retardant property needs to be developed to meet the demands of market application.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a glass fiber reinforced heat conduction polyamide composite material. In particular to a glass fiber reinforced heat conduction polyamide composite material, a preparation method and application thereof. The composite material has excellent heat conducting performance, mechanical performance and flame retardant property, low production cost and is suitable for large-scale production.

According to the glass fiber reinforced heat-conducting polyamide composite material, the glass fiber and the composite heat-conducting filler are introduced through the preparation method of formula regulation and stepwise dispersion blending, so that the polyamide composite material with excellent heat conduction, mechanical and flame retardant properties is prepared, meanwhile, as different components of the glass fiber and the composite heat-conducting filler play a role in synergism, the dispersion is uniform, the heat conduction property is improved, the addition amount of the auxiliary agent is reduced, and the prepared polyamide composite material has excellent comprehensive properties and is widely applied to the fields of LED illumination, communication equipment, electric and electronic industry, household appliances, automobiles and the like.

One of the purposes of the invention is to provide a glass fiber reinforced heat conduction polyamide composite material, which comprises the following components in percentage by weight, based on 100% by weight of the composite material:

20-50% of polyamide resin; preferably 20-40%;

10-50%, preferably 10-30% of glass fibers;

30-60% of composite heat conducting filler; preferably 30-50%.

Wherein,

the polyamide resin may be used in an amount of 20 to 50%, preferably 20 to 40%; specifically, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50% or any value between the above values or a range of values between any two of the above values;

the glass fibers may be used in an amount of 10 to 50%, preferably 10 to 30%; specifically, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50% or any value or range of values between any two of the above values;

The dosage of the composite heat conducting filler can be 30-60%; preferably 30-50%; specifically, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60% or any value between the above values or a range of values between any two of the above values may be used.

In the glass fiber reinforced heat conductive polyamide composite material, the polyamide resin can be selected from one or a mixture of more of PA6, PA66, PA11, PA12, PA46, PA610, PA612 and PA 1010. Preferably, the polyamide resin has a relative viscosity of 1.6 to 3.5; more preferably, the relative viscosity is 1.8 to 2.4 (for example, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5 or any value between the above values or a range of values between any two of the above values). Specifically, at least one of the high gloss and high fluidity PA6 and the commercial PA6 product as disclosed in chinese patent CN102911355 a; meanwhile, the polyamide resin may be a composition of a low-viscosity polyamide resin and a high-medium-viscosity polyamide resin, and the relative viscosity of the polyamide composition is preferably 1.6 to 3.5 (for example, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5 or any value between the above values or a range of values between any two of the above values).

In the glass fiber reinforced heat-conducting polyamide composite material, the glass fiber can be at least one of alkali-free short glass fiber, long glass fiber and flat glass fiber; preferably, the glass fibers may be selected from alkali-free short glass fibers and/or long glass fibers;

preferably, the glass fibers may be selected from alkali-free short glass fibers, and the glass fibers may have a length of 1-6mm (e.g., may be 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, or any value therebetween or a range of values therebetween); the glass fibers may have a filament diameter of 9-20 μm (e.g., may be 9 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, or any value therebetween or a range of values therebetween);

or,

preferably, the glass fibers may be selected from long glass fibers, and the length of the glass fibers may be 6-25mm (e.g., may be 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 25mm, or any value therebetween or a range of values therebetween); the glass fibers may have a filament diameter of 9-20 μm (e.g., may be 9 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, or any value therebetween or a range of values therebetween).

The glass fiber is preferably at least one selected from alkali-free short glass fiber with the length of 1-6mm and the monofilament diameter of 9-20 mu m, and long glass fiber with the length of 6-25mm and the monofilament diameter of 9-20 mu m; the glass fibers are commercially available from a number of manufacturers, including Chongqing International company ER4301 brand products.

In the glass fiber reinforced heat-conducting polyamide composite material, the composite heat-conducting filler can comprise a heat-conducting main material and a heat-conducting auxiliary material, wherein the heat-conducting main material can be at least one selected from metal oxides and metal hydroxides, and the heat-conducting auxiliary material can be an inorganic nano material.

The composite heat-conducting filler can comprise the following components in percentage by weight, based on 100% of the amount of the composite heat-conducting filler:

50-98% of heat conducting main material, preferably 70-95%;

2-50%, preferably 5-30% of heat conducting auxiliary material.

The amount of the heat conducting main material can be 50-98%, preferably 70-95%; specifically, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 84%, 95%, 96%, 97%, 98% or any value between the above values or a range of values between any two of the above values may be used.

The amount of the heat conducting auxiliary material can be 2-50%, preferably 5-30%; specifically, the ratio may be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50% or any value between the above values or a range of values between any two of the above values, for example, 8% to 25%, etc.

Wherein,

the metal oxide may comprise at least one of large-sized metal oxide particles and small-sized metal oxide particles;

and/or the number of the groups of groups,

the metal oxide can be at least one selected from aluminum oxide, antimonous oxide, titanium dioxide and magnesium oxide, preferably selected from aluminum oxide and/or magnesium oxide.

Wherein,

the particle diameter of the large-sized metal oxide particles may be 10 μm to 100 μm (for example, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm, 30 μm, 34 μm, 38 μm, 40 μm, 44 μm, 48 μm, 52 μm, 56 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm or any value between the above values or a value range between any two of the above values), and is preferably 20 μm to 60 μm; and/or the number of the groups of groups,

The particle diameter of the small-sized metal oxide particles may be 100nm to 20 μm (for example, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm or any value between the above values or a range of values between any two of the above values), and is preferably 100nm to 10 μm; and/or the number of the groups of groups,

the metal hydroxide may comprise at least one of large-size metal hydroxide particles and small-size metal hydroxide particles; and/or the number of the groups of groups,

the metal hydroxide may be at least one selected from magnesium hydroxide, aluminum hydroxide, titanium hydroxide, and antimony hydroxide, preferably magnesium hydroxide and/or aluminum hydroxide.

And/or the number of the groups of groups,

the particle diameter of the large-size metal hydroxide particles may be 10 μm to 100 μm (e.g., 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm, 30 μm, 34 μm, 38 μm, 40 μm, 44 μm, 48 μm, 52 μm, 56 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm or any value between the above values or a value range between any two of the above values), and preferably 20 μm to 60 μm; and/or the number of the groups of groups,

The particle diameter of the small-sized metal hydroxide particles may be 100nm to 20. Mu.m (for example, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1. Mu.m, 2. Mu.m, 3. Mu.m, 4. Mu.m, 5. Mu.m, 6. Mu.m, 7. Mu.m, 8. Mu.m, 9. Mu.m, 10. Mu.m, 15. Mu.m, 20. Mu.m, or any value between the above values or a value range between any two of the above values), and is preferably 100nm to 10. Mu.m.

In the specific implementation, in the composite heat-conducting filler, the particle size of the metal oxide and the metal hydroxide can be 1-100 mu m; the metal oxide and the metal hydroxide may be specifically selected from at least one of alumina, antimony trioxide, titanium dioxide, magnesium oxide, aluminum hydroxide and magnesium hydroxide having a particle size of 1 μm to 100. Mu.m, preferably at least one of alumina, magnesium oxide, aluminum hydroxide and magnesium hydroxide having a particle size of 1 μm to 100. Mu.m, more preferably at least one of alumina, magnesium oxide, aluminum hydroxide and magnesium hydroxide having a particle size of 1 μm to 40. Mu.m.

In the composite heat-conducting filler, the inorganic nano material can be at least one selected from carbon nano tubes, modified carbon nano tubes, carbon black, crystalline flake graphite, graphene, boron nitride, boron carbide, aluminum nitride and silicon carbide. Wherein the modified carbon nanotube can be at least one selected from fluorine modified carbon nanotube, boron modified carbon nanotube, sulfur modified carbon nanotube and nitrogen modified carbon nanotube, preferably fluorine modified carbon nanotube.

Preferably, the fluorine element content of the fluorine-modified carbon nanotube may be 0 to 30% (e.g., 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30% or any value between the above values or a range between any two of the above values), and preferably 2 to 20%. The modified carbon nanotubes described above may be modified by various modification methods in the prior art. The fluorine modified carbon nanotube, boron modified carbon nanotube, sulfur modified carbon nanotube, nitrogen modified carbon nanotube and the like can be all the modified carbon nanotube products commercially available in the prior art.

More preferably, the particle size of the inorganic nanomaterial may be 1 μm to 100 μm (e.g., 1 μm, 2 μm, 4 μm, 6 μm, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm, 30 μm, 34 μm, 38 μm, 40 μm, 44 μm, 48 μm, 52 μm, 56 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, or any value between any two of the values described above); the inorganic nano material can be specifically selected from at least one of carbon nano tube, modified carbon nano tube, boron nitride, aluminum nitride and silicon carbide with the particle size of 1-100 mu m. Wherein,

The fluorine modified carbon nanotubes described in the present invention can be obtained by reacting components including fluorine-containing compounds and carbon nanotubes.

The preparation method of the fluorine modified carbon nano tube specifically comprises the following steps: is prepared from the components including fluorine-containing compound and carbon nanotubes through reaction. Preferably, the fluorine-containing compound and the carbon nano tube are uniformly mixed before the reaction; preferably, the obtained heat conduction auxiliary material can be cleaned and ground after being cooled after the reaction. Preferably, the reaction temperature can be 350-500 ℃ and the reaction time can be 2-6 h.

Wherein,

the fluorine-containing compound can be at least one selected from polytetrafluoroethylene, polyvinylidene fluoride and polytrifluoroethylene; and/or the number of the groups of groups,

the ratio of the fluorine-containing compound to the carbon nanotube may be (1-100): 1 (for example, 1:1, 2:1, 4:1, 6:1, 8:1, 10:1, 15:1, 20:1, 30:1, 35:1, 40:1, 45:1, 50:1, 55:1, 60:1, 65:1, 70:1, 75:1, 80:1, 85:1, 90:1, 95:1, 100:1, or any value between the above values or a range of values between any two of the above values), and preferably (10-80): 1.

The preparation method of the composite heat-conducting filler can comprise the following steps: the heat-conducting composite filler is obtained by blending the components comprising the heat-conducting main material and the heat-conducting auxiliary material.

The preparation method of the composite heat-conducting filler specifically comprises the following steps: mixing the components including the heat conducting main material and the heat conducting auxiliary material according to the dosage, and stirring to obtain the composite heat conducting filler; preferably, the stirring speed is 1000 to 10000rpm, more preferably 3000 to 10000rpm, and the stirring time is 1 to 15 minutes, more preferably 3 to 10 minutes.

In the implementation of the present invention, in order to improve the impact resistance of the glass fiber reinforced heat conductive polyamide composite material, the glass fiber reinforced heat conductive polyamide composite material may further include a toughening agent; the toughening agent can be at least one selected from polyolefin copolymers, preferably from grafted polyolefin copolymers, more preferably from maleic anhydride grafted hydrogenated styrene-butadiene block copolymers, maleic anhydride grafted ethylene-octene copolymers, glycidyl methacrylate grafted ethylene copolymers;

preferably, the toughening agent may be used in an amount of 0 to 7% (e.g., 1%, 2%, 3%, 4%, 5%, 6%, 7% or any value therebetween or a range of values therebetween), preferably 1 to 5%, based on 100% by weight of the total glass fiber reinforced thermally conductive polyamide composite material.

In the implementation of the invention, in order to improve the compatibility of the heat conducting filler and the matrix resin and improve the mechanical property and the heat conducting property of the glass fiber reinforced heat conducting polyamide composite material, the glass fiber reinforced heat conducting polyamide composite material can further comprise a surface modifier; the surface modifier can improve the dispersion performance of the heat conducting filler in the matrix resin and make the binding force of the heat conducting filler and the matrix stronger, thereby achieving the purpose of improving the mechanical property and the heat conducting property of the heat conducting thermoplastic resin composite material. Wherein the surface modifier can be at least one selected from anhydride compounds, silane compounds and amide compounds, preferably at least one selected from maleic anhydride, silane coupling agents and polyvinylpyrrolidone; preferably, the surface modifier may be used in an amount of 0-2% (e.g., may be 0.01%, 0.04%, 0.1%, 0.3%, 0.5%, 0.7%, 0.9%, 1.0%, 1.2%, 1.3%, 1.5%, 1.7%, 1.9%, 2.0% or any value or range of values between any two of the foregoing) based on 100% by weight of the glass fiber reinforced thermally conductive polyamide composite, preferably 0.01-2%, more preferably 0.01-1.5%.

In the practice of the present invention,

in addition, the glass fiber reinforced heat-conducting polyamide composite material can also comprise other auxiliary agents such as antioxidants and the like which are common in the processing of the polyamide composite material. The antioxidant can be at least one selected from calcium stearate, hindered phenol compounds and phosphite compounds, and the antioxidant components can be used singly or in combination, and more preferably in combination, and are used for avoiding oxidation of the resin in the processing process; the hindered phenol compound and the phosphite compound can be antioxidant products commonly used in the field, such as antioxidant 1010, antioxidant 168, antioxidant 1098 and the like.

Preferably, the antioxidant may be used in an amount of 0-2% (e.g., may be 0.01%, 0.04%, 0.1%, 0.3%, 0.5%, 0.7%, 0.9%, 1.0%, 1.2%, 1.3%, 1.5%, 1.7%, 1.9%, 2.0% or any value between the above values or a range of values between any two of the above values), preferably 0.01-2%, more preferably 0.01-1%, based on 100% by weight of the total glass fiber reinforced thermally conductive polyamide composite material.

The second purpose of the invention is to provide a preparation method of the glass fiber reinforced heat conduction polyamide composite material, which comprises the following steps: the glass fiber reinforced heat conducting polyamide composite material is obtained by mixing (or in particular, graded mixing and compounding) and melt blending (or in particular, multiple melt blending) the components comprising the polyamide resin, the glass fiber and the composite heat conducting filler.

Specifically, the preparation method of the glass fiber reinforced heat conduction polyamide composite material can comprise the following steps:

uniformly mixing the components including the polyamide resin, the optional toughening agent and the optional antioxidant to obtain a mixed material;

step (2), putting the mixed material in the step (1) into a main feeding hopper by using a double-screw extruder with side feeding or continuous long fiber infiltration coating complete equipment, feeding glass fibers through a side feeding port, carrying out double-screw melt blending, extruding and granulating to obtain glass fiber reinforced polyamide resin slices;

uniformly mixing the components including the glass fiber reinforced polyamide resin obtained in the step (2), the composite heat conducting filler and the optional surface modifier, (preferably spraying the surface modifier while stirring) to obtain a mixed material;

and (4) melting and blending the mixed material obtained in the step (3) by using a double-screw extruder to obtain the glass fiber reinforced heat-conducting polyamide composite material.

Preferably, the polyamide resin requires a drying treatment at 60 to 120℃for 6 to 24 hours before mixing, and the drying treatment may be performed by a heating and drying apparatus commonly used in the art, such as a forced air drying oven;

The weight of the polyamide resin is 20-50%, preferably 20-40% based on 100% of the weight of the glass fiber reinforced heat conductive polyamide composite material; the weight of the glass fiber is 10-50%, preferably 10-30%; the weight of the composite heat conducting filler is 30-60%, preferably 30-50%.

0-7% by weight, preferably 1-5% by weight, of toughening agent can be added in the step (1) based on 100% by weight of the glass fiber reinforced heat conducting polyamide composite material;

the step (3) may further comprise 0-2%, preferably 0.01-2%, more preferably 0.01-1.5% by weight of a surface modifier, based on 100% by weight of the glass fiber reinforced heat conductive polyamide composite material;

other commonly used components, such as 0-2%, preferably 0.01-2%, more preferably 0.01-1% of antioxidant by weight percent based on 100% of the weight of the glass fiber reinforced heat conductive polyamide composite material, can be added into the composite material;

the materials in the step (1) can be mixed evenly by adopting a manual stirring or mechanical stirring mode, for example, the materials are stirred evenly in a high-speed stirrer at 500-20000 rpm for 1-10 minutes or the materials are stirred manually for 1-10 minutes;

The melt blending in the step (2) is carried out on a twin-screw extruder or continuous long fiber infiltration coating complete equipment, the melt blending temperature can be 200-245 ℃, the twin-screw extruder can be a common twin-screw extruder, the mixed material is put into the twin-screw extruder, the rotating speed of the screw can be set to be 60-150 rpm, the main feeding speed can be 5-20 rpm, the temperature of each section of the twin-screw extruder from one section to six sections can be 200-245 ℃, the molten extrusion is carried out through the twin-screw extruder, the molten extrusion is carried out into strips, the cooling forming is carried out through a water tank, and then the strips enter a granulator for granulating, thus obtaining the glass fiber reinforced polyamide resin.

The materials in the step (3) can be mixed by adopting a manual stirring or mechanical stirring mode to uniformly mix the glass fiber reinforced polyamide resin, the composite heat conducting filler and the surface modifier, for example, the surface modifier is sprayed while stirring in a high-speed stirrer, the rotating speed can be 500-20000 rpm, the stirring time can be 1-10 minutes, or the surface modifier is sprayed while stirring manually, and the stirring time can be 1-10 minutes;

the melt blending in the step (4) is carried out on a double-screw extruder, the melt blending temperature is 200-245 ℃, the double-screw extruder can be a common double-screw extruder, the mixed material is put into the double-screw extruder, the screw rotating speed is set to be 60-150 rpm, the main feeding speed is 5-20 rpm, the temperature of each section of the double-screw extruder from one section to six sections is 200-245 ℃, the glass fiber reinforced heat conduction polyamide composite material is obtained through the melt extrusion of the double-screw extruder, the drawing and the cooling molding of a water tank, and then the glass fiber reinforced heat conduction polyamide composite material is obtained through the granulating of a granulator.

The glass fiber reinforced heat conducting polyamide composite material obtained by the preparation method has excellent comprehensive performance, and the heat conductivity of the composite material is 0.8-5.5. 5.5W m ^-1 K ^-1 The tensile strength is 55-120 MPa, and the notch impact strength is 3-15 KJ m ^-2 The bending strength is 80-150 MPa; preferably, the thermal conductivity of the composite material is 1.0-4.0W m ^-1 K ^-1 The tensile strength is 65-120 MPa, and the notch impact strength is 5-10 KJ m ^-2 The bending strength is 90-150 MPa. The composite material has excellent heat conducting performance, mechanical performance and flame retardant property, is easy to process by injection molding, and is very suitable for being used as engineering plastics for shells of LED illumination, communication equipment, electric and electronic industry, household appliances, new energy automobiles and the like.

The third object of the present invention is to provide an application of the glass fiber reinforced heat conductive polyamide composite material according to one of the objects of the present invention or the glass fiber reinforced heat conductive polyamide composite material prepared by the preparation method according to the second object of the present invention, preferably an application in the fields of LED lighting, communication equipment, electric and electronic industry, household appliances, automobiles (such as new energy automobiles) and the like, particularly an application on a housing material.

According to the invention, the heat conduction auxiliary material and the heat conduction main material are mixed to obtain the composite heat conduction filler, and the obtained composite heat conduction filler is uniformly distributed in the polyamide resin, so that a high-efficiency heat conduction network can be formed, the heat conduction main material and the heat conduction auxiliary material exert a synergistic effect, and the heat conduction performance, the mechanical performance and the flame retardant performance of the polyamide resin composite material are comprehensively improved. Meanwhile, the heat conduction auxiliary material has the effect of reinforcing and toughening, and can further generate a synergistic effect when being used for compounding glass fibers and composite materials, thereby being beneficial to improving the mechanical properties of the composite materials.

Compared with the method for adding the heat conducting filler commonly used in the prior art, the invention provides the composite heat conducting filler, and the thermoplastic resin composite material with high heat conduction, high mechanical property and flame retardant property is prepared. The composite heat conducting filler solves the difficulty that the heat conduction, the high mechanical property and the flame retardant property cannot be considered in the prior art, and has unexpected outstanding effects.

Compared with the prior art, the invention has the following beneficial effects:

(1) In the invention, glass fiber and composite heat conducting filler are adopted to replace common heat conducting filler, in the combined formula, the glass fiber can form a skeleton heat conducting network, and the composite heat conducting filler is uniformly dispersed among the skeleton heat conducting networks of the glass fiber, so that the synergistic effect can be exerted to improve the heat conducting performance of polyamide resin, and the mechanical property of the composite material can be comprehensively improved;

(2) In the invention, a preparation method of stepwise dispersion blending is adopted, namely, the glass fiber reinforced polyamide resin is prepared by firstly mixing the polyamide resin and the additive and adding glass fibers through a double-screw extruder, then the glass fiber reinforced polyamide resin and the composite heat-conducting filler are mixed at the same time of spraying the surface modifier, and the glass fiber reinforced heat-conducting polyamide composite material is prepared through a double-screw extruder. Compared with common one-time blending, the preparation method of the composite material has the beneficial effects of improving the filling proportion of the glass fiber and the composite heat-conducting filler, improving the dispersion uniformity of the glass fiber and the composite heat-conducting filler and the like;

(3) The glass fiber reinforced heat-conducting polyamide composite material provided by the invention has excellent comprehensive performance, can be prepared by adopting a double-screw extruder, has a simple preparation process and low production cost, is suitable for large-scale production, is easy to process and form, and has a wide application prospect.

Drawings

FIG. 1 is a flow chart of a preparation process of a glass fiber reinforced heat conducting polyamide composite material provided by the invention;

fig. 2 is a cross-sectional electron micrograph of the glass fiber-reinforced thermally conductive polyamide composite material obtained in example 1, and it can be seen that the glass fibers form a skeleton structure in the polyamide resin, and the composite thermally conductive filler composed of spherical magnesium oxide particles and boron nitride is uniformly dispersed in the polyamide resin matrix.

Detailed Description

The present invention is described in detail below with reference to specific embodiments, and it should be noted that the following embodiments are only for further description of the present invention and should not be construed as limiting the scope of the present invention, and some insubstantial modifications and adjustments of the present invention by those skilled in the art from the present disclosure are still within the scope of the present invention.

The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.

The heat conductive thermoplastic resin composite material of the present invention was tested according to the following criteria:

tensile strength: GB/T1040-2006.

Flexural strength, flexural modulus: GB/T9341-2008.

Test method of impact properties (cantilever beam): GB-/T1843-2008.

UL-94 vertical burn test: GB/T2408-2008. The specific classification criteria for the UL-94 test are shown below.

Grade HB: the lowest flame retardant rating in the UL-94 standard. It is required that for samples 3 to 13 mm thick, the burn rate is less than 40 mm per minute; for samples less than 3 millimeters thick, the burn rate is less than 70 millimeters per minute; or extinguished before the 100 mm mark.

If the sample cannot reach HB level, it is stepless (No Rating, NR).

The starting materials used in the examples and comparative examples:

nylon 6 (PA 6): high fluidity PA6 with relative viscosity of 1.9-2.2, provided by Baling petrochemical industry;

glass fiber: ER4301H, alkali-free glass fiber, diameter 17 μm, linear density 2400tex, manufactured by Chongqing International composite Material Co., ltd;

silane coupling agent: KH561, purchased from alaa Ding Gongsi;

heat conducting main material, magnesia powder: the particle size was 4 μm from Shanghai hundred chart high New Material technologies Co., ltd;

heat conducting main material, magnesium hydroxide powder: the particle size was 10 μm, purchased from Shanghai hundred chart high New Material technologies Co., ltd;

Heat conducting auxiliary material, boron nitride powder (BN): the particle size was 10 μm, purchased from Shanghai hundred chart high New Material technologies Co., ltd;

heat conducting auxiliary material, modified carbon nano tube: and (5) homemade in a laboratory. The preparation method of the fluorine modified carbon nano tube serving as the specific heat conduction auxiliary material comprises the following steps: the heat conducting auxiliary material is obtained by reacting fluorine-containing compound with commercial carbon nano tube.

At least one of polytetrafluoroethylene, polyvinylidene fluoride and polytrifluoroethylene is uniformly mixed with carbon nano tubes, the mixture is placed in a crucible, then the reaction time is 2 to 6 hours at the temperature of 350 to 500 ℃, after the reaction is finished, a mixture sample is naturally cooled, deionized water is used for cleaning and grinding, and the multi-wall carbon nano tube powder grafted by fluorine atoms can be obtained. For example, uniformly mixing carbon nanotubes (multi-wall carbon nanotubes, flotube 9000, manufactured by Tianney technology Co., ltd.) and polytetrafluoroethylene according to a mass ratio of 1:20, reacting at 450 ℃ for 3 hours, naturally cooling a mixture sample after the reaction, and cleaning with deionized water to obtain fluorine atom grafted multi-wall carbon nanotube powder with fluorine element content of 2.1%, namely the fluorine modified carbon nanotubes for later use.

Toughening agent POE-g-MAH, brand CMG5805, preferably Yi Rong;

Calcium stearate, available from alaa Ding Gongsi;

antioxidant 1010, available from BASF corporation;

antioxidant 168, available from BASF corporation.

The raw materials used in examples and comparative examples, if not particularly limited, are all as disclosed in the prior art, and are, for example, available directly or prepared according to the preparation methods disclosed in the prior art.

The glass fiber reinforced heat conduction polyamide composite material provided by the embodiment of the invention adopts the following preparation method:

(1) Placing the high-fluidity PA6 into a forced air drying oven for drying for 12 hours, wherein the drying temperature is 80 ℃;

(2) Placing 20-50% of dry PA6, 0-7% of POE toughening agent and 0.01-2% of composite antioxidant (compounded by calcium stearate, antioxidant 1010 and antioxidant 168 in a weight ratio of 0.5:1:1) in a high-speed stirrer, uniformly mixing at a rotating speed of 10000rpm for 5 minutes, and obtaining a mixed material;

(3) Putting the mixed materials into a double-screw extruder, setting the rotating speed of the screw to 80rpm, setting the main feeding speed to 10rpm, setting the temperature of a first area of the double-screw extruder to 220 ℃, setting the temperature of a second area of the double-screw extruder to 235 ℃, setting the temperature of a third area of the double-screw extruder to 240 ℃, setting the temperature of a fourth area of the double-screw extruder to 240 ℃, setting the temperature of a fifth area of the double-screw extruder to 240 ℃, setting the temperature of a sixth area of the double-screw extruder to 235 ℃, adding alkali-free glass fibers with the total mass of 10-30% into a glass fiber feeding port of the extruder, melting and extruding the glass fiber into strips, cooling and molding the strips through a water tank, and then granulating the strips by a granulator to obtain glass fiber reinforced polyamide resin slices;

(4) Spraying silane coupling agent accounting for 0.01-2% of the total mass into 30-60% of composite heat conducting filler (magnesium oxide with the particle size of 4 mu m and/or magnesium hydroxide with the particle size of 10 mu m are used as heat conducting main materials, boron nitride or modified carbon nano tubes with the particle size of 10 mu m are used as heat conducting auxiliary materials) while stirring, and uniformly mixing the composite heat conducting filler with the glass fiber reinforced polyamide resin slices in a stirrer at the rotating speed of 1000rpm for 5 minutes to obtain a mixed material;

(5) The mixed materials are put into a double-screw extruder, the rotating speed of the screw is set to be 80rpm, the main feeding speed is set to be 10rpm, the temperature of a first area of the double-screw extruder is 220 ℃, the temperature of a second area of the double-screw extruder is 235 ℃, the temperature of a third area of the double-screw extruder is 240 ℃, the temperature of a fourth area of the double-screw extruder is 240 ℃, the temperature of a fifth area of the double-screw extruder is 240 ℃, the temperature of a sixth area of the double-screw extruder is 235 ℃, the double-screw extruder is used for melting extrusion, drawing into strips, cooling and molding are carried out through a water tank, and then the strips enter a granulator for granulating, so that the glass fiber reinforced heat-conducting polyamide composite material is obtained.

Examples 1 to 10:

examples 1-10 provided glass fiber reinforced thermally conductive polyamide composites of different raw material ratios, the mass fractions of the components in each example being shown in table 1.

TABLE 1 mass fraction tables of the components of the Polyamide composite materials of the examples

Comparative example 1:

(2) Placing 32% of dry PA6, 59% of heat conduction main material (magnesium oxide with the particle size of 4 mu m), 6% of heat conduction auxiliary material (boron nitride with the particle size of 10 mu m), 2% of POE toughening agent, 0.3% of composite antioxidant (compounded by calcium stearate, antioxidant 1010 and antioxidant 168 in a mass ratio of 0.5:1:1) and 0.7% of silane coupling agent into a high-speed stirrer, uniformly mixing at the rotating speed of 10000rpm for 5 minutes, and obtaining a mixed material;

(3) The mixed materials are put into a double-screw extruder, the rotating speed of the screw is set to be 80rpm, the main feeding speed is set to be 10rpm, the temperature of a first area of the double-screw extruder is 220 ℃, the temperature of a second area of the double-screw extruder is 235 ℃, the temperature of a third area of the double-screw extruder is 240 ℃, the temperature of a fourth area of the double-screw extruder is 240 ℃, the temperature of a fifth area of the double-screw extruder is 240 ℃, the temperature of a sixth area of the double-screw extruder is 235 ℃, the double-screw extruder is used for melting extrusion, the double-screw extruder is pulled into strips, the strips are cooled and formed through a water tank, and then the strips enter a granulator for granulating, so that the polyamide composite material is obtained.

Comparative example 2:

(2) Placing dry PA6 accounting for 32% of the total mass, 59% of heat conducting main material (magnesium hydroxide with the particle size of 10 mu m), 6% of heat conducting auxiliary material (boron nitride with the particle size of 10 mu m), 2% of POE toughening agent, 0.3% of composite antioxidant (compounded by calcium stearate, antioxidant 1010 and antioxidant 168 according to the ratio of 0.5:1:1) and 0.7% of silane coupling agent into a high-speed stirrer, uniformly mixing, wherein the rotating speed is 10000rpm, and the stirring time is 5 minutes, so as to obtain a mixed material;

Comparative example 3:

(2) Placing dried PA6 accounting for 32 percent of the total mass, POE toughening agent accounting for 2 percent of the total mass, composite antioxidant accounting for 0.3 percent (compounded by calcium stearate, antioxidant 1010 and antioxidant 168 according to the ratio of 0.5:1:1) and silane coupling agent accounting for 0.7 percent into a high-speed stirrer, uniformly mixing at the rotating speed of 10000rpm for 5 minutes, and obtaining a mixed material;

(3) The mixed materials are put into a double-screw extruder, the rotating speed of the screw is set to be 80rpm, the main feeding speed is set to be 10rpm, the temperature of a first area of the double-screw extruder is 220 ℃, the temperature of a second area of the double-screw extruder is 235 ℃, the temperature of a third area of the double-screw extruder is 240 ℃, the temperature of a fourth area of the double-screw extruder is 240 ℃, the temperature of a fifth area of the double-screw extruder is 240 ℃, the temperature of a sixth area of the double-screw extruder is 235 ℃, alkali-free glass fiber with 65% of the total mass is added into a glass fiber feeding port of the extruder, the glass fiber is melted and extruded through the double-screw extruder, drawn into strips, cooled and molded through a water tank, and then the strips enter a granulator for granulating, so as to obtain the polyamide composite material.

Comparative example 4:

(2) Placing dry PA6 accounting for 32% of the total mass, 4% of heat conduction auxiliary materials (boron nitride with the particle size of 10 mu m), 2% of POE toughening agents, 0.3% of composite antioxidants (compounded by calcium stearate, antioxidant 1010 and antioxidant 168 according to the ratio of 0.5:1:1) and 0.7% of silane coupling agents into a high-speed stirrer, uniformly mixing at the rotating speed of 10000rpm for 5 minutes, and obtaining a mixed material;

(3) The mixed materials are put into a double-screw extruder, the rotating speed of the screw is set to be 80rpm, the main feeding speed is set to be 10rpm, the temperature of a first area of the double-screw extruder is 220 ℃, the temperature of a second area of the double-screw extruder is 235 ℃, the temperature of a third area of the double-screw extruder is 240 ℃, the temperature of a fourth area of the double-screw extruder is 240 ℃, the temperature of a fifth area of the double-screw extruder is 240 ℃, the temperature of a sixth area of the double-screw extruder is 235 ℃, alkali-free glass fiber accounting for 61% of the total mass of the glass fiber is added into a glass fiber feeding port of the extruder, and the glass fiber is melted and extruded through the double-screw extruder, drawn into strips, cooled and molded through a water tank, and then enters a granulator for granulating, so as to obtain the polyamide composite material.

Comparative example 5:

(2) Mixing dry PA6 accounting for 32% of the total mass, POE toughening agent accounting for 2% of the total mass and composite antioxidant accounting for 0.3% of the total mass (compounded by calcium stearate, antioxidant 1010 and antioxidant 168 in a mass ratio of 0.5:1:1) uniformly in a high-speed stirrer at a rotating speed of 10000rpm for 5 minutes to obtain a mixed material;

(3) The mixed materials are put into a double-screw extruder, the rotating speed of the screw is set to 80rpm, the main feeding speed is set to 10rpm, the temperature of a first area of the double-screw extruder is 220 ℃, the temperature of a second area of the double-screw extruder is 235 ℃, the temperature of a third area of the double-screw extruder is 240 ℃, the temperature of a fourth area of the double-screw extruder is 240 ℃, the temperature of a fifth area of the double-screw extruder is 240 ℃, the temperature of a sixth area of the double-screw extruder is 235 ℃, alkali-free glass fiber accounting for 21% of the total mass of the glass fiber is added into a glass fiber feeding port of the extruder, and the glass fiber is melted and extruded through the double-screw extruder, drawn into strips, cooled and molded through a water tank, and then enters a granulator for granulating, so as to obtain the polyamide composite material.

(4) Spraying silane coupling agent with the total mass of 0.7% into 44% of heat conducting filler (magnesium oxide with the particle size of 4 mu m) while stirring, and uniformly mixing the silane coupling agent and the polyamide composite material in a stirrer at the rotating speed of 1000rpm for 5 minutes to obtain a mixed material;

(5) The mixed materials are put into a double-screw extruder, the rotating speed of the screw is set to be 80rpm, the main feeding speed is set to be 10rpm, the temperature of a first area of the double-screw extruder is 220 ℃, the temperature of a second area of the double-screw extruder is 235 ℃, the temperature of a third area of the double-screw extruder is 240 ℃, the temperature of a fourth area of the double-screw extruder is 240 ℃, the temperature of a fifth area of the double-screw extruder is 240 ℃, the temperature of a sixth area of the double-screw extruder is 235 ℃, the double-screw extruder is used for melting extrusion, the double-screw extruder is pulled into strips, the strips are cooled and formed through a water tank, and then the strips enter a granulator for granulating, so that the polyamide composite material is obtained.

Comparative example 6:

(2) Placing 32% of dry PA6, 40% of heat conduction main material (magnesium oxide with the particle size of 4 mu m), 4% of heat conduction auxiliary material (boron nitride with the particle size of 10 mu m), 2% of POE toughening agent, 0.3% of composite antioxidant (compounded by calcium stearate, antioxidant 1010 and antioxidant 168 in a mass ratio of 0.5:1:1) and 0.7% of silane coupling agent into a high-speed stirrer, uniformly mixing at the rotating speed of 10000rpm for 5 minutes, and obtaining a mixed material;

Comparative examples 1-6 provide polyamide composites having different raw material ratios, and the mass fractions of the components in each comparative example are shown in table 2.

TABLE 2 comparative polyamide composite materials component mass fraction tables

The prepared composite materials were made into standard bars by using an injection molding apparatus, and the heat conductive properties, mechanical properties and flame retardant properties of the polyamide composite materials provided in examples 1 to 7 and comparative examples 1 to 6 were tested, and the results are shown in Table 3.

Table 3 results of the performance test of the polyamide composite materials prepared in examples and comparative examples

As can be seen from the data of examples 1 to 7 and comparative examples 1 to 6 and table 3, the addition of the glass fiber, the composite heat conductive filler and the toughening agent can have a great influence on the heat conduction, mechanical properties, flame retardance and other properties of the composite material, and particularly, the addition of the glass fiber can obviously improve the mechanical properties of the composite material, and the addition of the glass fiber, the heat conduction main material and the heat conduction auxiliary material affects the interaction among the components of the composite material, so that the comprehensive properties of the composite material are improved, and the polyamide composite material with good mechanical properties, high heat conduction properties and flame retardance can be realized.

Comparing examples 1-10 of the present invention with comparative examples 1 and 2, it can be seen that the addition of glass fibers can significantly improve the mechanical properties of the composite material, in particular the tensile strength, flexural strength and impact strength.

In the present invention, examples 1 to 10 are compared with comparative examples 3 and 4, comparative example 3 is a common glass fiber reinforced polyamide resin, and comparative example 4 is a polyamide resin having a heat conductive auxiliary material added thereto based on comparative example 3, and although such a method can improve the mechanical properties of the polyamide resin, they cannot have excellent heat conductive properties and flame retardant properties, and thus cannot meet the use requirements.

Compared with comparative example 5, examples 3-5, 8 and 9 of the present invention are common glass fiber reinforced heat conducting methods (only glass fiber and magnesia are added as heat conducting fillers), and although the method can also improve the mechanical and heat conducting properties of polyamide resin, the method can not realize high heat conduction and flame retardant property, which means that the addition of proper heat conducting auxiliary materials with high heat conducting properties can not only greatly improve the heat conducting properties (up to about 100 percent) of the composite material, but also play a role in improving the flame retardant property, because the heat conducting auxiliary materials are inorganic nano materials, and can play a role in flame retardant. Meanwhile, when the modified carbon nano tube is used as a heat conduction auxiliary material, a better heat conduction network can be formed between the heat conduction main materials, so that the composite material has better heat conduction performance.

In comparison with comparative example 6, the formulation of comparative example 6 was the same as that of example 1, but the processing was different, and in comparative example 6, a heat conductive filler, glass fiber and other auxiliary agents were added by one-time twin-screw extrusion. As can be seen from comparison of experimental data results, the mechanical properties and the heat conducting properties of comparative example 6 are lower than those of example 1, because the example adopts the preparation method of stepwise dispersion blending, the beneficial effects of more uniformly dispersing the heat conducting filler, glass fiber and other auxiliary agents in the polyamide resin can be realized.

As can be seen from the section electron microscope photograph of the glass fiber reinforced heat-conducting polyamide composite material of the embodiment 1 shown in fig. 2, the glass fiber forms a skeleton structure in the polyamide resin, the composite heat-conducting filler consisting of spherical magnesium oxide particles and boron nitride is uniformly dispersed in the polyamide resin matrix, and different components interact and are closely connected to form a high-efficiency and stable heat-conducting network, and meanwhile, the heat-conducting auxiliary material is favorable for uniformly dispersing the composite heat-conducting filler, so that the comprehensive mechanical property of the composite material is improved.

Claims

1. A glass fiber reinforced thermally conductive polyamide composite material, based on 100% of the weight of the composite material, containing the following components in weight percentage:

Polyamide resin 20-50%, preferably 20-40%;

Glass fiber 10-50%, preferably 10-30%;

Composite thermally conductive filler 30-60%; preferably 30-50%.

2. The glass fiber reinforced thermally conductive polyamide composite material according to claim 1, characterized in that:

The polyamide resin is selected from one or a mixture of more than one of PA6, PA66, PA11, PA12, PA46, PA610, PA612 and PA1010;

Preferably, the relative viscosity of the polyamide resin is 1.6-3.5; more preferably, the relative viscosity is 1.8-2.4.

3. The glass fiber reinforced thermally conductive polyamide composite material according to claim 1, characterized in that:

The glass fiber is selected from at least one of alkali-free short glass fiber, long glass fiber and flat glass fiber; preferably, the glass fiber is selected from alkali-free short glass fiber and/or long glass fiber;

Preferably, the glass fiber is selected from alkali-free short glass fibers, the length of the glass fiber is 1-6 mm; the single filament diameter of the glass fiber is 9-20 μm;

Preferably, the glass fiber is selected from long glass fibers, the length of the glass fiber is 6-25 mm; the single filament diameter of the glass fiber is 9-20 μm.

4. The glass fiber reinforced thermally conductive polyamide composite material according to claim 1, characterized in that:

The composite thermally conductive filler includes a thermally conductive main material and a thermally conductive auxiliary material, the thermally conductive main material is selected from at least one of metal oxides and metal hydroxides, and the thermally conductive auxiliary material is selected from inorganic nanomaterials.

5. The glass fiber reinforced thermally conductive polyamide composite material according to claim 1, characterized in that:

Based on the dosage of the composite thermally conductive filler being 100%, the composite thermally conductive filler includes the following components in weight percent:

The thermal conductive main material is 50-98%, preferably 70-95%;

The thermal conductive auxiliary material is 2-50%, preferably 5-30%.

6. The glass fiber reinforced thermally conductive polyamide composite material according to claim 4, characterized in that:

The metal oxide includes at least one of large-sized metal oxide particles and small-sized metal oxide particles; the particle size of the large-sized metal oxide particles is preferably 10 μm to 100 μm, and more preferably 20 μm to 60 μm. ; The particle size of the small-sized metal oxide particles is preferably 100 nm to 20 μm, more preferably 100 nm to 10 μm;

and / or,

The metal oxide is selected from at least one of alumina, antimony trioxide, titanium dioxide, and magnesium oxide, and is preferably selected from alumina and/or magnesium oxide.

7. The glass fiber reinforced thermally conductive polyamide composite material according to claim 4, characterized in that:

The metal hydroxide includes at least one of large-size metal hydroxide particles and small-size metal hydroxide particles; the particle size of the large-size metal hydroxide particles is preferably 10 μm to 100 μm, more preferably It is 20 μm to 60 μm; the particle size of the small-sized metal hydroxide particles is preferably 100 nm to 20 μm, and more preferably 100 nm to 10 μm;

and / or,

The metal hydroxide is selected from at least one of magnesium hydroxide, aluminum hydroxide, titanium hydroxide, and antimony hydroxide, and is preferably selected from magnesium hydroxide and/or aluminum hydroxide.

8. The glass fiber reinforced thermally conductive polyamide composite material according to claim 4, characterized in that:

In the composite thermally conductive filler, the metal oxide and metal hydroxide are selected from at least one of alumina, antimony trioxide, titanium dioxide, magnesium oxide, aluminum hydroxide, and magnesium hydroxide with a particle size of 1 μm to 100 μm. One, preferably at least one selected from aluminum oxide, magnesium oxide, aluminum hydroxide, and magnesium hydroxide with a particle size of 1 μm to 100 μm, more preferably aluminum oxide, magnesium oxide, and aluminum hydroxide with a particle size of 1 μm to 40 μm. , at least one of magnesium hydroxide.

9. The glass fiber reinforced thermally conductive polyamide composite material according to claim 4, characterized in that:

In the composite thermally conductive filler, the inorganic nanomaterial is selected from at least one of carbon nanotubes, modified carbon nanotubes, carbon black, flake graphite, graphene, boron nitride, boron carbide, aluminum nitride, and silicon carbide. One; the modified carbon nanotubes are preferably at least one of fluorine-modified carbon nanotubes, boron-modified carbon nanotubes, sulfur-modified carbon nanotubes, and nitrogen-modified carbon nanotubes, and more preferably fluorine-modified carbon nanotubes. carbon nanotubes; preferably, the mass percentage of fluorine element in the fluorine-modified carbon nanotubes is 0 to 30%, preferably 2 to 20%.

10. The glass fiber reinforced thermally conductive polyamide composite material according to claim 4, characterized in that:

The particle size of the inorganic nanomaterial is 1 μm to 100 μm;

Preferably, the inorganic nanomaterial is preferably selected from at least one of carbon nanotubes, modified carbon nanotubes, boron nitride, aluminum nitride, and silicon carbide with a particle size of 1 μm to 100 μm.

11. The glass fiber reinforced thermally conductive polyamide composite material according to claim 9, characterized in that:

The fluorine-modified carbon nanotubes are obtained by reacting components including fluorine-containing compounds and carbon nanotubes; preferably, the components including the fluorine-containing compounds and carbon nanotubes are reacted before the reaction. Mix evenly; preferably, the reaction temperature is 350-500°C, and the reaction time is 2-6 hours.

12. The glass fiber reinforced thermally conductive polyamide composite material according to claim 11, characterized in that:

The fluorine-containing compound is selected from at least one of polytetrafluoroethylene, polyvinylidene fluoride, polychlorodifluoroethylene, and polychlorotrifluoroethylene; and/or,

The usage ratio of the fluorine-containing compound and the carbon nanotube is (1-100):1, preferably (10-80):1.

13. The glass fiber reinforced thermally conductive polyamide composite material according to any one of claims 1 to 12, characterized in that:

The preparation method of the composite thermally conductive filler includes the following steps: blending components including a thermally conductive main material and a thermally conductive auxiliary material to obtain the thermally conductive composite filler.

14. The glass fiber reinforced thermally conductive polyamide composite material according to claim 13, characterized in that:

The preparation method of the composite thermally conductive filler includes the following steps: mixing components including the thermally conductive main material and the thermally conductive auxiliary material, and stirring to obtain the composite thermally conductive filler; the preferred stirring speed is 1000-10000rpm, and the preferred stirring time is 1-15min.

15. The glass fiber reinforced thermally conductive polyamide composite material according to claim 1, characterized in that it also contains a toughening agent; the toughening agent is selected from polyolefin copolymers, preferably from grafted polyolefin copolymers. material, more preferably selected from the group consisting of maleic anhydride-grafted hydrogenated styrene-butadiene block copolymer, maleic anhydride-grafted ethylene-octene copolymer, and glycidyl methacrylate-grafted vinyl copolymer. at least one;

Preferably, based on the total weight of the glass fiber reinforced thermally conductive polyamide composite material being 100%, the amount of the toughening agent is 0-7%, preferably 1-5%.

16. The glass fiber reinforced thermally conductive polyamide composite material according to claim 1, characterized in that it also contains a surface modifier; the surface modifier is selected from at least one of anhydride compounds, silane compounds, and amide compounds. , preferably at least one selected from maleic anhydride, silane coupling agent, and polyvinylpyrrolidone;

Preferably, based on the total weight of the glass fiber reinforced thermally conductive polyamide composite material being 100%, the amount of the surface modifier is 0-2%, preferably 0.01-1.5%.

17. The glass fiber reinforced thermally conductive polyamide composite material according to claim 1, characterized in that it also contains an antioxidant; the antioxidant is preferably selected from calcium stearate, hindered phenolic compounds, and phosphites. at least one of the compounds;

Preferably, based on the total weight of the glass fiber reinforced thermally conductive polyamide composite material being 100%, the amount of the antioxidant is 0-2%, preferably 0.01-1%.

18. The glass fiber reinforced thermally conductive polyamide composite material according to any one of claims 1 to 17, characterized in that the thermal conductivity of the glass fiber reinforced thermally conductive polyamide composite material is 0.8 to 5.5W m ^-1 K ^{- 1} .

19. The method for preparing a glass fiber reinforced thermally conductive polyamide composite material according to any one of claims 1 to 18, characterized by comprising the following steps: combining the polyamide resin, glass fiber and composite thermally conductive filler After the included components are mixed and melt-blended, the glass fiber reinforced thermally conductive polyamide composite material is obtained.

20. The preparation method of glass fiber reinforced thermally conductive polyamide composite material according to claim 19, characterized by comprising the following steps:

Step (1), mix the components including the polyamide resin, optional toughening agent, and optional antioxidant evenly to obtain a mixed material;

Step (2), preferably a twin-screw extruder with side feeding or a complete set of continuous long fiber infiltration coating equipment; put the mixed material described in step (1) into the main feeding hopper, and the glass fiber passes through the side feeding port After feeding in materials, melting, blending, extrusion and granulation, glass fiber reinforced polyamide resin is obtained;

Step (3): Mix the components including the glass fiber reinforced polyamide resin, composite thermally conductive filler, and optional surface modifier obtained in step (2) evenly to obtain a mixed material;

Step (4): After melting and blending the mixed materials obtained in step (3), the glass fiber reinforced thermally conductive polyamide composite material is obtained.

21. Application of the glass fiber reinforced thermally conductive polyamide composite material according to any one of claims 1 to 18 or the glass fiber reinforced thermally conductive polyamide composite material prepared according to the preparation method according to claim 19 or 20, preferably in Applications in LED lighting, communication equipment, electrical and electronic industries, household appliances, and automobiles.