A toughened and modified thermally conductive polyamide composite material, its preparation method and application

Abstract

This invention relates to the field of polymer composite materials technology, and provides a toughened modified thermally conductive polyamide composite material, its preparation method, and its application. The toughened modified thermally conductive polyamide composite material includes an inner core material and at least one outer layer material; the inner core material includes a first polyamide resin, fibers, and a first additive, with the fibers continuously extending from one end of the inner core material to its opposite end; the outer layer material encapsulates the inner core material, and the outer layer material includes a second polyamide resin, a thermally conductive filler, a toughening agent, and a second additive. The toughened modified thermally conductive polyamide composite material solves the technical difficulty of filler-substrate dispersion caused by the high content of glass fiber, filler, and toughening agent in traditional thermally conductive polymer processing, and has good processability, surface quality, and mechanical properties, exhibiting excellent impact performance, especially low-temperature impact performance.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials, and more specifically, to a toughened modified thermally conductive polyamide composite material, its preparation method, and its application. Background Technology

[0002] Polyamide (nylon, PA), as an engineering plastic, not only possesses excellent mechanical properties (such as tensile properties, flexural properties, and compressive strength), but also exhibits low-temperature resistance, chemical stability, ease of processing and molding, and excellent wear resistance. It is widely used in many fields, including electronics, automobiles, aerospace, and machinery. However, polyamide also has drawbacks such as brittleness and poor impact resistance. Furthermore, its heat resistance and strength are relatively low compared to the requirements of certain high-end applications.

[0003] To address the aforementioned shortcomings, glass fiber / carbon fiber is commonly used to reinforce polyamides, improving the overall performance of polyamide composites. Long fiber reinforced thermoplastic composites are a common type of thermoplastic composite and one of the fastest-growing materials in the current composite materials market. The fiber length of long fiber reinforced thermoplastics is equal to the length of the material particles, with highly consistent fiber orientation. They possess characteristics such as low density, ease of molding, high specific strength, high modulus, good fatigue resistance, and non-absorbency. Furthermore, compared to short fiber reinforced thermoplastic composites, long fiber reinforced thermoplastics offer better dimensional stability, excellent impact resistance, chemical stability, and recyclability, making them particularly suitable for applications with frequent high and low temperature fluctuations. They can be injection molded on ordinary injection molding machines or compression molded, making them ideal candidates for metal substitutes. Currently, with the continuous improvement of long fiber reinforced thermoplastic composite technology and the expansion of its application cases, as well as the increasing awareness of health, safety, and environmental protection and the continuous advancement of product high-end and intelligent processes, higher and more demanding requirements have been placed on the performance of materials. Materials need to possess excellent mechanical properties, be multifunctional to meet the needs of high-end applications, and also take into account processing performance and the performance requirements of molded parts. For example, for large and complex parts in automobiles and aerospace, and high-precision electronic components, there are high requirements for the high flowability, processability, dimensional stability, and surface quality of materials.

[0004] In addition, polyamide materials themselves have very low thermal conductivity, only 0.2–0.3 W / m². -1 K -1In emerging fields such as 5G, photovoltaics, LED lighting, and mobile phones, the thermal conductivity of polyamides needs to be modified to meet the requirements. Chinese patents CN106380838A, CN108003607B, and CN104140670A disclose a flame-retardant polyamide-based thermally conductive material and its preparation method, a flame-retardant thermally conductive nylon composite material and its preparation method, and a high thermal conductivity nylon composite material and its preparation method, respectively. These methods all use the traditional twin-screw extrusion process to prepare polyamide composite materials. Due to the excessively high proportion of filler in the composite material, the thermally conductive filler, glass fiber, and toughening agent are difficult to disperse. Furthermore, the glass fiber is shortened by shearing during processing, resulting in a decrease in the overall mechanical properties of the final material, which fails to meet the requirement of being both "rigid and tough" and thus cannot satisfy the needs of some high-end application fields.

[0005] The existing technologies cannot meet the needs of practical applications to address the aforementioned problems. Therefore, the development of continuous fiber-reinforced thermally conductive polyamide composites with good processing performance, high toughness, uniform filler dispersion, and high filler content, as well as their production processes and applications, has significant market value and research significance. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a toughened modified thermally conductive polyamide composite material, its preparation method, and its application.

[0007] The technical solution adopted in this invention is:

[0008] In a first aspect, the present invention proposes a toughened modified thermally conductive polyamide composite material, comprising an inner core material and at least one outer layer material; the inner core material comprises a first polyamide resin, fibers and a first additive, wherein the fibers extend continuously from one end of the inner core material to its opposite end; the outer layer material encapsulates the inner core material, and the outer layer material comprises a second polyamide resin, a thermally conductive filler, a toughening agent and a second additive.

[0009] As a preferred embodiment of the composite material provided by the present invention, in the core material, the amount of the first polyamide resin is 1-90 parts by weight, preferably 25-70 parts by weight, more preferably 25-45 parts by weight; and the amount of fiber is 5-99 parts by weight, preferably 20-60 parts by weight, more preferably 30-50 parts by weight.

[0010] And / or, in the core material, the weight ratio of fiber to first polyamide resin is (0.25-6):1, preferably (0.5-2):1;

[0011] And / or, in the outer layer material, the amount of the second polyamide resin is 1-99 parts by weight, preferably 15-90 parts by weight, more preferably 20-70 parts by weight, and even more preferably 25-45 parts by weight; the amount of the thermally conductive filler is 1-100 parts by weight, preferably 25-80 parts by weight, more preferably 30-70 parts by weight; and the amount of the toughening agent is 1-30 parts by weight, preferably 3-25 parts by weight, and more preferably 5-20 parts by weight.

[0012] As another preferred embodiment of the composite material provided by the present invention, the first polyamide resin and the second polyamide resin may be the same or different, and each is independently selected from at least one of aliphatic polyamide, semi-aromatic polyamide, aromatic polyamide and copolyamide and their alloy polymers; preferably, the first polyamide resin and the second polyamide resin may be the same or different, and each is independently selected from at least one of nylon 6, nylon 66, a mixture of nylon 6 and nylon 66, nylon 1010, nylon 11, nylon 12, nylon 610, nylon 612, nylon 6T and nylon 10T;

[0013] And / or, the fiber is carbon fiber or glass fiber or a mixture of both; preferably, the carbon fiber is at least one of polyacrylonitrile-based carbon fiber, petroleum pitch-based carbon fiber, coal tar pitch-based carbon fiber, viscose-based carbon fiber, phenolic-based carbon fiber, vapor-grown carbon fiber, bacterial cellulose-based carbon fiber, cellulose-based carbon fiber and lignin-based carbon fiber.

[0014] As another preferred embodiment of the composite material provided by the present invention, the thermally conductive filler includes a thermally conductive main material and a thermally conductive auxiliary material, wherein the thermally conductive main material is selected from metal oxides and / or metal hydroxides, and the thermally conductive auxiliary material is selected from inorganic powders;

[0015] Preferably, based on the total weight of the thermally conductive filler, the content of the main thermally conductive material is 50-98 wt%, and the content of the auxiliary thermally conductive material is 2-50 wt%.

[0016] As another preferred embodiment of the composite material provided by the present invention, the thermally conductive main material is selected from at least one of alumina, antimony trioxide, titanium dioxide, magnesium oxide, aluminum hydroxide, and magnesium hydroxide, and preferably at least one of alumina, magnesium oxide, aluminum hydroxide, and magnesium hydroxide.

[0017] And / or, the particle size of the thermally conductive main material is 1-100 μm, preferably 1-40 μm;

[0018] And / or, the inorganic powder is selected from at least one of carbon nanotubes, carbon black, flake graphite, graphene, boron nitride, boron carbide, aluminum nitride, and silicon carbide, preferably at least one of boron nitride, aluminum nitride, and silicon carbide;

[0019] And / or, the particle size of the inorganic powder is 1 to 100 μm.

[0020] As another preferred embodiment of the composite material provided by the present invention, the toughening agent is selected from at least one of polyolefin copolymers, special rubbers, biodegradable polyesters, natural rubbers and bio-based elastomers;

[0021] Preferably, it is selected from at least one of polybutylene terephthalate (PBAT), polybutylene terephthalate (PBST), polybutylene succinate (PBS) and its copolymers, polyhydroxy fatty acids (PHA), polycaprolactone (PCL), natural rubber, ethylene-octene copolymer (POE) and its modifiers, hydrogenated nitrile butadiene rubber, and functionalized solution polystyrene-butadiene rubber;

[0022] More preferably, it is at least one of polybutylene adipate terephthalate (PBAT), polybutylene terephthalate succinate (PBST), ethylene-octene copolymer (POE) and its maleic anhydride modified form, and hydrogenated nitrile rubber;

[0023] More preferably, maleic anhydride modified with ethylene-octene copolymer (POE) and hydrogenated nitrile butadiene rubber;

[0024] In a further preferred embodiment, the weight ratio of the maleic anhydride-modified ethylene-octene copolymer (POE) to the hydrogenated nitrile rubber is 0.2 to 5.

[0025] As another preferred embodiment of the composite material provided by the present invention, the first additive includes at least one of 0.3-15 parts by weight of a first compatibilizer, 0.1-3 parts by weight of a first antioxidant, and 0.5-1 parts by weight of a first lubricant; preferably, it includes at least one of 1-5 parts by weight of a first compatibilizer, 0.1-1 parts by weight of a first antioxidant, and 0.5-1 parts by weight of a first lubricant.

[0026] And / or, the second additive comprises at least one of 0.3-15 parts by weight of a second compatibilizer, 0.1-3 parts by weight of a second antioxidant, and 0.5-1 parts by weight of a second lubricant; preferably, it comprises at least one of 1-5 parts by weight of a second compatibilizer, 0.1-1 parts by weight of a second antioxidant, and 0.5-1 parts by weight of a second lubricant.

[0027] As another preferred embodiment of the composite material provided by the present invention, the first compatibilizer and the second compatibilizer may be the same or different, and each is independently selected from at least one of maleic anhydride-grafted polypropylene, maleic anhydride-grafted ethylene-octene copolymer, titanate coupling agent and aluminate coupling agent.

[0028] And / or, the first antioxidant and the second antioxidant may be the same or different, each independently selected from at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), tris[2,4-di-tert-butylphenyl] phosphite (antioxidant 168), octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1076), 2,2'-methylenebis(4-methyl-6-tert-butylphenol) (antioxidant 2246), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane (antioxidant CA), and pentaerythritol diphosphite (2,4-di-tert-butylphenol) (antioxidant 626);

[0029] And / or, the first lubricant and the second lubricant may be the same or different, each independently selected from at least one of ethylene bis-stearamide, calcium stearate, polyethylene wax and pentaerythritol stearate.

[0030] As another preferred embodiment of the composite material provided by the present invention, the core material does not contain non-oriented short fibers. Preferably, the core material is composed of a first polyamide resin, fibers and a first auxiliary agent.

[0031] Secondly, the present invention provides a method for preparing the above-mentioned toughened modified thermally conductive polyamide composite material, comprising:

[0032] S1. The first polyamide resin and the first additive are mixed and melted to obtain the first component melt;

[0033] S2. The continuous fibers are subjected to a first impregnation treatment with the first component melt in step S1 to form a filamentous core material;

[0034] S3. The second polyamide resin, thermally conductive filler, toughening agent and second additive are mixed and melted to obtain the second component melt;

[0035] S4. The core material obtained in step S2 is subjected to at least one second impregnation treatment with at least one second component melt obtained in step S3 to obtain a toughened modified thermally conductive polyamide composite material.

[0036] Preferably, the mixing conditions in step S1 are: a temperature of 40-60°C and a time of 3-5 min; and / or a melting temperature of 220-380°C in step S1.

[0037] And / or, the mixing conditions in step S3 are: temperature of 40-60℃, time of 3-5 min; and / or the melting temperature in step S3 is 220-380℃;

[0038] And / or, step S2 further includes: dispersing and preheating the continuous fibers before the first impregnation treatment; preferably, the temperature of the preheating treatment is 80-250°C;

[0039] And / or, step S4 further includes: after the second impregnation treatment, performing pull-out, strip-drawing, cooling, drying, and pelletizing treatment on the material obtained by the second impregnation treatment to obtain a toughened modified thermally conductive polyamide composite material.

[0040] As another preferred embodiment of the preparation method provided by the present invention, in step S2, the first impregnation treatment is performed in a first impregnation mold. The first impregnation mold is an adjustable impregnation mold, which includes a fiber inlet, a fiber outlet, and a melt flow channel. At least one first guide roller is provided in the mold cavity of the first impregnation mold. The first guide roller is movable between the fiber inlet and the fiber outlet. And / or, the first guide roller is movable along a direction perpendicular to the line connecting the fiber inlet and the fiber outlet.

[0041] As another preferred embodiment of the preparation method provided by the present invention, in step S2, the first impregnation treatment is carried out in the second impregnation mold. The second impregnation mold is a combined impregnation mold, which includes a first module, an intermediate module and a second module connected in sequence. The first module is provided with a fiber inlet and a first module flow channel. The second module is provided with a fiber outlet and a second module flow channel. The intermediate module is provided with an intermediate module flow channel. After the first module, the intermediate module and the second module are connected in sequence, the first module flow channel, the intermediate module flow channel and the second module flow channel are connected to form a combined flow channel for the fiber to pass through.

[0042] As another preferred embodiment of the preparation method provided by the present invention, in step S2, the first impregnation treatment is carried out in a third impregnation mold. The third impregnation mold is a strong turbulent impregnation mold. The third impregnation mold includes a fiber inlet channel, an impregnation outlet, and a melt gap flow channel. The fiber inlet channel, the impregnation outlet, and the melt gap flow channel are all connected to the mold cavity inside the third impregnation mold. A second guide roller is provided inside the mold cavity of the third impregnation mold. The second guide roller includes at least one active guide roller, which is driven to rotate by a driving device.

[0043] Thirdly, the present invention provides applications of the above-mentioned toughened modified thermally conductive polyamide composite material or the toughened modified thermally conductive polyamide composite material prepared by the above-mentioned preparation method in the fields of automotive industry, machinery manufacturing, electronics and electrical appliances, chemical and environmental protection, aerospace and communications and construction industry; preferably in the application of large automotive parts and / or high-precision electronic and electrical components, more preferably in the application of automotive front-end modules and / or all-plastic tailgate inner panels.

[0044] The beneficial effects of this invention are at least as follows:

[0045] 1. The toughened modified thermally conductive polyamide composite material provided by this invention has an inner and outer composite structure, which makes it easy to achieve synergistic effects between different components. It greatly improves the fluidity of fibers in resin melt and the dispersion of inorganic particles in composite material system, which can effectively improve the processing performance of composite material. It avoids the technical difficulties of poor dispersion performance caused by high content of glass fiber, filler, toughening agent, etc. in the processing of traditional thermally conductive polymers, and the common difficulties in the dispersion of filler-substrate. In particular, it solves the problems of aggregation and bridging between multiphase fillers caused by the simultaneous blending of fibers and a large amount of thermally conductive fillers. It can prepare continuous fiber reinforced thermally conductive composite materials with good processability and excellent mechanical properties.

[0046] 2. The toughened modified thermally conductive polyamide composite material provided by this invention features an outer toughening and inner reinforcement structure, which better helps absorb energy from external forces and fields, thus improving the material's impact performance. The toughening agent, composed of maleic anhydride modified from hydrogenated nitrile rubber and ethylene-octene copolymer, exhibits better compatibility with the polymer matrix compared to traditional toughening agents, giving the toughened modified thermally conductive polyamide composite material superior impact performance, especially low-temperature impact performance.

[0047] 3. The toughened modified thermally conductive polyamide composite material provided by this invention has greatly improved the comprehensive performance and surface quality, while reducing the requirements of injection molding process, expanding the application range of thermoplastic composite materials, and has broad application prospects and economic significance.

[0048] 4. The preparation method of the present invention is simple to operate, can realize online continuous production, can ensure high production capacity and low energy consumption, and is suitable for industrial production and application. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the toughened modified thermally conductive polyamide composite material structure in one embodiment of the present invention;

[0050] Figure 2 This is a schematic diagram of a toughened modified thermally conductive polyamide composite material manufacturing system according to one embodiment of the present invention;

[0051] Figure 3 This is a schematic diagram of the structure of a toughened modified thermally conductive polyamide composite material manufacturing system according to another embodiment of the present invention;

[0052] Figure 4 This is a cross-sectional view of the first impregnation mold in one embodiment of the present invention;

[0053] Figure 5This is a cross-sectional view of the second impregnation mold in one embodiment of the present invention;

[0054] Figure 6 This is a cross-sectional view of the third impregnation mold in one embodiment of the present invention;

[0055] Figure 7 This is a schematic diagram of the second impregnation treatment in one embodiment of the present invention;

[0056] Figure 8 This is a cross-sectional view of the molding die used in the second impregnation process according to one embodiment of the present invention.

[0057] Explanation of reference numerals in the attached figures:

[0058] 0-1, Inner core material; 0-2, Fiber bundle; 0-3, Outer layer material;

[0059] 1. Fiber rack and fiber guiding device; 2. Fiber pretreatment device; 3. First impregnation mold; 4. Melting and plasticizing feeding device; 5. Molding mold; 6. Cooling water tank; 7. Dryer; 8. Traction machine; 9. Pelletizer; 10. Collection box;

[0060] A300, First impregnation die head; A1, Fiber inlet; A2, Second chute; A3, Melt flow channel; A4, First chute; A5, Upper die cover; A6, Fiber outlet; A7, Impregnation die body; A8, First guide roller;

[0061] B300, Second impregnation die head; B1, Fiber inlet; B2, Melt channel; B3, First module; B31, First module channel; B4, Combined channel; B5, Standardized connector; B6, Intermediate module; B61, Intermediate module channel; B7, Second module; B71, Second module channel; B8, Fiber outlet;

[0062] C300, Third impregnation die head; C1, Melt flow channel; C2, Impregnation die body; C3, Fiber inlet channel; C4, Active guide roller; C5, Driven guide roller; C6, Impregnation outlet;

[0063] 4-1. Extruder I; 4-2. Extruder II;

[0064] 5-1 Core; 5-2 Outer shell; 5-3 Outer shell opening template; 5-4 Material strip; 5-5 Second resin inlet. Detailed Implementation

[0065] To make the technical problem to be solved, the technical solution, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely for illustrating this patent and do not limit the scope of protection of this invention in any way.

[0066] In a first aspect, the toughened modified thermally conductive polyamide composite material proposed in this invention includes an inner core material and at least one outer layer material; the inner core material includes a first polyamide resin, fibers and a first additive, the fibers extending continuously from one end of the inner core material to its opposite end; the outer layer material encapsulates the inner core material, the outer layer material including a second polyamide resin, thermally conductive filler, toughening agent and a second additive.

[0067] The inventors of this application have discovered that by impregnating continuous fibers with a first component comprising a first polyamide resin and a first additive to form an inner core material, and uniformly coating the outer side of the inner core material with a second component comprising a second polyamide resin, a thermally conductive filler, a toughening agent, and a second additive, a toughened modified thermally conductive polyamide composite material is formed, with continuous fiber reinforced resin as the inner core material and a resin layer wrapped around the outer side of the inner core material as the outer layer material. Such a polyamide composite material has excellent mechanical properties and good impact performance, especially low-temperature impact performance.

[0068] In this invention, the terms "one end" and "opposite end" are generally used in relation to the longitudinal direction of the toughened modified thermally conductive polyamide composite material.

[0069] In the transverse cross section of the toughened modified thermally conductive polyamide composite material, from the inside out are the inner core material and the outer layer material, and the fibers are oriented along the longitudinal direction of the toughened modified thermally conductive polyamide composite material in the inner core material.

[0070] The fibers in this invention are fiber bundles, and the length of the fiber bundles is substantially the same as the length (longitudinal dimension) of the toughened modified thermally conductive polyamide composite material. Thus, the fiber bundles extend continuously from one end of the inner core material in the longitudinal direction to the opposite end in the longitudinal direction. The inner core material does not contain short fibers, particularly non-oriented short fibers.

[0071] In the toughened modified thermally conductive polyamide composite material of the present invention, the outer layer material covers at least 80% of the inner core material, for example, 80-99% or 85-95% of the inner core material; the outer layer material may also continuously cover the inner core material.

[0072] The number of outer layers is not limited; it can be one or more layers. In some embodiments, the multiple outer layers can be formed from the same material or from multiple materials.

[0073] According to some embodiments of the present invention, the first polyamide resin and the second polyamide resin are each independently selected from at least one of aliphatic polyamide, semi-aromatic polyamide, aromatic polyamide and copolyamide and their alloy polymers.

[0074] According to some embodiments of the present invention, the first polyamide resin and the second polyamide resin are each independently selected from at least one of nylon 6, nylon 66, a mixture of nylon 6 and nylon 66, nylon 1010, nylon 11, nylon 12, nylon 610, nylon 612, nylon 6T and nylon 10T.

[0075] According to some embodiments of the present invention, the viscosity of the first polyamide resin is 1-5, preferably 1.5-4, more preferably 1.6-2.8. And / or, the viscosity of the second polyamide resin is 1-5, preferably 1.5-4, more preferably 1.6-2.8. In the present invention, the viscosity of the polyamide is the relative viscosity determined according to the Engler viscosity determination method GB / T266-88.

[0076] In different embodiments of the present invention, the viscosity of the first polyamide resin and the second polyamide resin is not particularly limited. For different production needs, the viscosity of the second polyamide resin can be selected to be higher than that of the first polyamide resin, or the viscosity of the first polyamide resin can be selected to be higher than that of the second polyamide resin.

[0077] According to some embodiments of the present invention, the viscosity ratio of the second polyamide resin to the first polyamide resin is 0.4-3.2, preferably 0.5-2.8, and more preferably 0.8-2.2. Wherein, the viscosity ratio of the second polyamide resin to the first polyamide resin is the value obtained by dividing the viscosity of the second polyamide resin by the viscosity of the first polyamide resin.

[0078] According to some embodiments of the present invention, the fiber may be carbon fiber, glass fiber, or a mixture of both. The carbon fiber is at least one selected from polyacrylonitrile-based carbon fiber, petroleum pitch-based carbon fiber, coal tar pitch-based carbon fiber, viscose-based carbon fiber, phenolic-based carbon fiber, vapor-grown carbon fiber, bacterial cellulose-based carbon fiber, cellulose-based carbon fiber, and lignin-based carbon fiber. The glass fiber is continuous glass fiber and / or fixed-length glass fiber.

[0079] According to some embodiments of the present invention, the composite material is in the form of strips, rods, or granules.

[0080] In this invention, the strip-shaped, rod-shaped, or granular toughened and modified thermally conductive polyamide composite material can be cut from a continuous filament-shaped toughened and modified thermally conductive polyamide composite material.

[0081] According to some embodiments of the present invention, the length of the strip-shaped or rod-shaped composite material is 6-25 mm, for example, it can be 6 mm, 8 mm, 10 mm, 12 mm, 15 mm, 20 mm, 22 mm, 25 mm, etc., preferably 8-20 mm, more preferably 10-15 mm; and / or the particle size of the granular composite material is 3-5 mm, for example, it can be 3 mm, 4 mm, 5 mm, etc., preferably 3-4 mm.

[0082] This invention does not impose special requirements on the cross-sectional shape of the toughened modified thermally conductive polyamide composite material. In some embodiments, the cross-section of the granular or rod-shaped toughened modified thermally conductive polyamide composite material is circular or near-circular. In other embodiments, the cross-section of the granular or strip-shaped toughened modified thermally conductive polyamide composite material is rectangular or square.

[0083] According to some embodiments of the present invention, in the core material, the amount of the first polyamide resin is 1-90 parts by weight, for example, 1 part by weight, 3 parts by weight, 5 parts by weight, 10 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 50 parts by weight, 52 parts by weight, 55 parts by weight, 57 parts by weight, 60 parts by weight, 70 parts by weight, 80 parts by weight, 99 parts by weight, etc., preferably 25-70 parts by weight, more preferably 25-45 parts by weight. The amount of fiber is 5-99 parts by weight, for example, 5 parts by weight, 10 parts by weight, 30 parts by weight, 40 parts by weight, 45 parts by weight, 52 parts by weight, 55 parts by weight, 60 parts by weight, 70 parts by weight, 80 parts by weight, 50 parts by weight, 99 parts by weight, etc., preferably 20-60 parts by weight, more preferably 30-50 parts by weight.

[0084] According to some embodiments of the present invention, in the core material, the weight ratio of fiber to first polyamide resin is (0.25-6):1, preferably (0.5-2):1.

[0085] According to some embodiments of the present invention, the amount of the second polyamide resin in the outer layer material is 1-99 parts by weight, for example, 1 part by weight, 3 parts by weight, 5 parts by weight, 10 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 50 parts by weight, 52 parts by weight, 55 parts by weight, 57 parts by weight, 60 parts by weight, 70 parts by weight, 80 parts by weight, 99 parts by weight, etc., preferably 15-90 parts by weight, more preferably 20-70 parts by weight, and even more preferably 25-45 parts by weight. The amount of the thermally conductive filler is 1-100 parts by weight, for example, 1 part by weight, 3 parts by weight, 5 parts by weight, 10 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 50 parts by weight, 52 parts by weight, 55 parts by weight, 57 parts by weight, 60 parts by weight, 70 parts by weight, 80 parts by weight, 100 parts by weight, etc., preferably 25-80 parts by weight, more preferably 30-70 parts by weight. The amount of toughening agent used is 1-30 parts by weight, for example, 1 part by weight, 3 parts by weight, 5 parts by weight, 8 parts by weight, 10 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, etc., preferably 3-25 parts by weight, more preferably 5-20 parts by weight.

[0086] According to some embodiments of the present invention, the thermally conductive filler includes a thermally conductive main material and a thermally conductive auxiliary material, wherein the thermally conductive main material is selected from metal oxides and / or metal hydroxides, and the thermally conductive auxiliary material is selected from inorganic powders.

[0087] According to some embodiments of the present invention, the content of the main thermally conductive material is 50-98 wt% based on the total weight of the thermally conductive filler, for example, it can be 50%, 55%, 60%, 70%, 75%, 80%, 87.5%, 90%, 98%, etc.; the content of the auxiliary thermally conductive material is 2-50 wt%, for example, it can be 2%, 5%, 10%, 12.5%, 20%, 30%, 35%, 40%, 50%, etc.

[0088] According to some embodiments of the present invention, the thermally conductive main material is selected from at least one of alumina, antimony trioxide, titanium dioxide, magnesium oxide, aluminum hydroxide, and magnesium hydroxide, preferably at least one of alumina, magnesium oxide, aluminum hydroxide, and magnesium hydroxide.

[0089] According to some embodiments of the present invention, the particle size of the thermally conductive main material is 1-100μm, for example, it can be 1μm, 2μm, 3μm, 4μm, 5μm, 8μm, 10μm, 15μm, 30μm, 50μm, 60μm, 80μm, 100μm, etc., preferably 1-40μm.

[0090] According to some embodiments of the present invention, the inorganic powder is selected from at least one of carbon nanotubes, carbon black, flake graphite, graphene, boron nitride, boron carbide, aluminum nitride, and silicon carbide, preferably at least one of boron nitride, aluminum nitride, and silicon carbide.

[0091] According to some embodiments of the present invention, the particle size of the inorganic powder is 1 to 100 μm. For example, it can be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 8 μm, 10 μm, 15 μm, 30 μm, 50 μm, 60 μm, 80 μm, 100 μm, etc.

[0092] According to some embodiments of the present invention, the toughening agent is selected from at least one of polyolefin copolymers, specialty rubbers, biodegradable polyesters, natural rubbers, and bio-based elastomers.

[0093] According to some preferred embodiments of the present invention, the toughening agent is at least one of polybutylene terephthalate (PBAT), polybutylene terephthalate (PBST), polybutylene succinate (PBS) and its copolymers, polyhydroxy fatty acid (PHA), polycaprolactone (PCL), natural rubber, ethylene-octene copolymer (POE) and its modifiers, hydrogenated nitrile butadiene rubber, and functionalized solution-polymerized styrene-butadiene rubber.

[0094] According to some preferred embodiments of the present invention, the toughening agent is at least one of polybutylene terephthalate (PBAT), polybutylene terephthalate (PBST), ethylene-octene copolymer (POE) and its maleic anhydride modified form, and hydrogenated nitrile rubber.

[0095] According to some preferred embodiments of the present invention, the toughening agent is a maleic anhydride modified ethylene-octene copolymer (POE) and hydrogenated nitrile rubber.

[0096] According to some preferred embodiments of the present invention, the toughening agent is a maleic anhydride modified ethylene-octene copolymer (POE) and the hydrogenated nitrile rubber in a weight ratio of 0.2 to 5, for example, 0.2, 0.25, 0.5, 1, 2, 3, 4, 5, etc.

[0097] According to some embodiments of the present invention, toughening agents comprising natural rubber and / or hydrogenated nitrile rubber require vulcanization treatment. The vulcanization treatment can employ commonly used rubber vulcanization processes.

[0098] In this invention, adding a toughening agent to the toughened modified thermally conductive polyamide composite material can improve the impact resistance of the composite material. The toughening agent can be prepared by crushing rubber through internal mixing-vulcanization, or it can be directly prepared into powder by spray drying.

[0099] According to some embodiments of the present invention, a method for preparing a maleic anhydride-modified ethylene-octene copolymer and a toughening agent for hydrogenated nitrile butadiene rubber includes:

[0100] The modified hydrogenated nitrile butadiene rubber masterbatch is prepared by mixing maleic anhydride modified ethylene-octene copolymer, hydrogenated nitrile butadiene rubber, and antioxidant.

[0101] Modified hydrogenated nitrile butadiene rubber masterbatch, zinc oxide, stearic acid, carbon black, antioxidant, vulcanizing agent and vulcanizing agent are mixed and then subjected to intensive mixing and vulcanization to obtain vulcanized rubber.

[0102] The toughening agent is obtained by physically crushing vulcanized rubber.

[0103] This invention does not limit the specific types and amounts of various additives in the first and second additives, with the aim of achieving the relevant properties of the composite material and realizing the function of the relevant additives.

[0104] According to some embodiments of the present invention, the first additive includes at least one of 0.3-15 parts by weight of a first compatibilizer, 0.1-3 parts by weight of a first antioxidant, and 0.5-1 parts by weight of a first lubricant; for example, the amount of the first compatibilizer may be 0.3 parts by weight, 0.5 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 5 parts by weight, 8 parts by weight, 10 parts by weight, 12 parts by weight, 15 parts by weight, etc.; and / or the amount of the first antioxidant may be 0.1 parts by weight, 0.2 parts by weight, 0.3 parts by weight, 0.5 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, etc.; and / or the amount of the first lubricant may be 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight, 1 part by weight, etc. Preferably, the first additive includes at least one of 1-5 parts by weight of a first compatibilizer, 0.1-1 parts by weight of a first antioxidant, and 0.5-1 parts by weight of a first lubricant.

[0105] According to some embodiments of the present invention, the second additive comprises at least one of 0.3-15 parts by weight of a second compatibilizer, 0.1-3 parts by weight of a second antioxidant, and 0.5-1 parts by weight of a second lubricant. For example, the amount of the second compatibilizer may be 0.3 parts by weight, 0.5 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 5 parts by weight, 8 parts by weight, 10 parts by weight, 12 parts by weight, 15 parts by weight, etc.; and / or the amount of the second antioxidant may be 0.1 parts by weight, 0.2 parts by weight, 0.3 parts by weight, 0.5 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, etc.; and / or the amount of the second lubricant may be 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight, 1 part by weight, etc. Preferably, the second additive comprises at least one of 1-5 parts by weight of a second compatibilizer, 0.1-1 parts by weight of a second antioxidant, and 0.5-1 parts by weight of a second lubricant.

[0106] According to some embodiments of the present invention, the first compatibilizer and the second compatibilizer may be the same or different, and each is independently selected from at least one of maleic anhydride-grafted polypropylene (PP-g-MAH, e.g., BONDYRAM 1001), maleic anhydride-grafted ethylene-octene copolymer (POE-g-MAH, e.g., CMG9805), titanate coupling agent (e.g., NDZ12), and aluminate coupling agent (e.g., XHY-501).

[0107] According to some embodiments of the present invention, the first antioxidant and the second antioxidant may be the same or different, and each is independently selected from at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), tris[2,4-di-tert-butylphenyl] phosphite (antioxidant 168), octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1076), 2,2'-methylenebis(4-methyl-6-tert-butylphenol) (antioxidant 2246), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane (antioxidant CA), and bis(2,4-di-tert-butylphenol) pentaerythritol diphosphite (antioxidant 626).

[0108] According to some embodiments of the present invention, the first lubricant and the second lubricant may be the same or different, and each is independently selected from at least one of ethylene bis-stearamide, calcium stearate, polyethylene wax and pentaerythritol stearate.

[0109] In different embodiments of the present invention, the first and second additives are not limited to specific types and amounts of these additives, and can have a wide range of selection. For example, the first and second additives may each independently include at least one of slip agents, antistatic agents, and plasticizers.

[0110] Secondly, the method for preparing the toughened modified thermally conductive polyamide composite material provided by the present invention includes:

[0111] S1. The first polyamide resin and the first additive are mixed and melted to obtain the first component melt;

[0112] S2. The continuous fibers are subjected to a first impregnation treatment with the first component melt in step S1 to form a filamentous core material;

[0113] S3. The second polyamide resin, thermally conductive filler, toughening agent and second additive are mixed and melted to obtain the second component melt;

[0114] S4. The core material obtained in step S2 is subjected to at least one second impregnation treatment with at least one second component melt obtained in step S3 to obtain the toughened modified thermally conductive polyamide composite material.

[0115] The preparation method of the present invention can be carried out online continuously to obtain continuous filamentous products. Such continuous filamentous products can be directly stored and used, or they can be cut into strips, rods or granules with a certain length or particle size.

[0116] According to some embodiments of the present invention, the mixing conditions of step S1 are: temperature of 40-60°C and time of 3-5 min; and / or the melting temperature of step S1 is 220-380°C.

[0117] According to some embodiments of the present invention, the mixing conditions of step S3 are: temperature of 40-60°C, time of 3-5 min; and / or the melting temperature of step S3 is 220-380°C.

[0118] In this invention, steps S1 and S3 and the melting time can have a wide range of selection, with the aim of enabling the first polyamide resin and the first additive, as well as the second polyamide resin, toughening agent and the second additive, to be fully melted to obtain a melt.

[0119] According to some embodiments of the present invention, step S2 further includes: dispersing and preheating the continuous fibers before subjecting them to the first impregnation treatment; preferably, the preheating temperature is 80-250°C. The dispersion process in the present invention employs conventional fiber dispersion processes in the art.

[0120] According to some embodiments of the present invention, step S4 further includes: after the second impregnation treatment, subjecting the material obtained by the second impregnation treatment to pull-out, stretching, cooling, drying, and pelletizing treatments to obtain a toughened modified thermally conductive polyamide composite material. The present invention does not particularly limit the process conditions for pull-out, stretching, cooling, drying, and pelletizing treatments, and those skilled in the art can adjust them according to the specific performance requirements of the prepared toughened modified thermally conductive polyamide composite material.

[0121] According to some embodiments of the present invention, the first impregnation process in step S2 can be performed in a first impregnation mold, the first impregnation mold being an adjustable impregnation mold, the first impregnation mold including a fiber inlet, a fiber outlet and a melt flow channel, and at least one first guide roller being disposed in the mold cavity of the first impregnation mold; the first guide roller is movable between the fiber inlet and the fiber outlet; and / or, the first guide roller is movable along a direction perpendicular to the line connecting the fiber inlet and the fiber outlet.

[0122] According to some embodiments of the present invention, the first impregnation process in step S2 can be performed in a second impregnation mold. The second impregnation mold is a combined impregnation mold, which includes a first module, an intermediate module, and a second module connected in sequence. The first module is provided with a fiber inlet and a first module flow channel, and the second module is provided with a fiber outlet and a second module flow channel. The intermediate module is provided with an intermediate module flow channel. After the first module, the intermediate module, and the second module are connected in sequence, the first module flow channel, the intermediate module flow channel, and the second module flow channel are connected to form a combined flow channel for the fiber to pass through.

[0123] According to some embodiments of the present invention, the first impregnation process in step S2 can also be performed in a third impregnation mold, the third impregnation mold being a strong turbulent impregnation mold, the third impregnation mold including a fiber inlet channel, an impregnation outlet and a melt gap flow channel, the fiber inlet channel, the impregnation outlet and the melt gap flow channel being connected to the mold cavity inside the third impregnation mold; wherein, a second guide roller is provided inside the mold cavity of the third impregnation mold, the second guide roller including at least one active guide roller, the active guide roller being driven to rotate by a driving device.

[0124] The first impregnation mold, the second impregnation mold, and the third impregnation mold used in this invention are described in Chinese patent applications CN202011193483.3, 202011191450.5, and 202011199839.4, the entire contents of which are incorporated herein by reference.

[0125] It should be noted that the first impregnation mold, the second impregnation mold, and the third impregnation mold described above in this invention can be applied to any existing manufacturing system and preparation technology for toughened modified thermally conductive polyamide composite materials.

[0126] According to some embodiments of the preparation method described in this invention, the second impregnation treatment in step S4 can be performed in a molding die. The molding die consists of a core, an outer jacket, and an outer jacket opening template. The core is located inside the outer jacket, forming a cavity with it. The resin melt can enter the cavity from the bottom, top, or both sides of the outer jacket. The core can move back and forth within the outer jacket, and the pressure of the melt in the cavity is determined by adjusting the size of the formed cavity space. The pressure of the melt in the cavity can also be adjusted by the angle between the core and the outer jacket. The working principle of this molding die is as follows: after passing through the impregnation die, a strip of inner impregnated material is formed, guided through the hole in the middle of the core, and then, in the cavity filled with the mixed melt formed by the core and the outer jacket, the composite structure of the inner and outer layers is formed, and finally, it is discharged through the outer jacket opening template.

[0127] The invention will now be further described with reference to the accompanying drawings.

[0128] Figure 1 The structure of the toughened modified thermally conductive polyamide composite material of the present invention is shown. For example... Figure 1 As shown, the cross-section of the toughened modified thermally conductive polyamide composite material of the present invention is circular, and from the inside out, it includes an inner core material 0-1 and an outer layer material 0-3. The inner core material 0-1 contains fiber bundles 0-2 that are oriented longitudinally, and the fiber bundles 0-2 are uniformly dispersed in the inner core material 0-1.

[0129] like Figure 2 and Figure 3 As shown, the manufacturing system of the present invention includes a fiber rack and fiber guiding device 1, a fiber pretreatment device 2, a first impregnation mold 3, a melt plasticizing feeding device 4, a molding mold 5, a cooling water tank 6, a dryer 7, a traction machine 8, a pelletizer 9, a collection box 10, and an electrical control system (not shown in the figure), which are connected in sequence.

[0130] In the manufacturing system, molding die 5 is used for molding the toughened and modified thermally conductive polyamide composite material, and its structure is as follows: Figure 8 As shown.

[0131] In the manufacturing system, the first impregnation mold 3 is used to impregnate the fiber with the first polyamide resin melt.

[0132] like Figure 4As shown, in one embodiment, the first impregnation mold is an impregnation device with an adjustable guide roller position, including a first impregnation mold head A300. The first impregnation mold head A300 includes an impregnation mold body A7, a fiber inlet A1, a fiber outlet A6, and a melt flow channel A3. At least one first guide roller A8 is provided in the mold cavity, wherein the first guide roller A8 is movable between the fiber inlet A1 and the fiber outlet A6, or the first guide roller A8 is movable along a direction perpendicular to the line connecting the fiber inlet A1 and the fiber outlet A6; or, the first guide roller A8 is movable both between the fiber inlet A1 and the fiber outlet A6 and along a direction perpendicular to the line connecting the fiber inlet A1 and the fiber outlet A6.

[0133] Taking a rectangular first impregnation mold head A300 as an example, the first impregnation mold head A300 is provided with a plurality of first guide rollers A8. The axial direction of each first guide roller A8 is the width direction of the first impregnation mold head A300. Therefore, each first guide roller A8 can move along the length direction of the first impregnation mold head A300 or along the height direction, thereby changing the position of the first guide roller A8 within the first impregnation mold head A300.

[0134] Understandably, the axial direction of the first guide roller A8 can also be the length direction of the first impregnation mold head A300. In this case, each first guide roller A8 can move along the width direction of the first impregnation mold head A300 or along the height direction of the first impregnation mold head A300, thereby changing the position of the first guide roller A8 within the first impregnation mold head A300.

[0135] Since the fiber needs to pass around the first guide roller A8 in sequence within the mold cavity of the first impregnation mold head A300, the fiber's path within the mold cavity can be altered by changing the position of the first guide roller A8 within the first impregnation mold head A300 (horizontal position, longitudinal position, etc.). Therefore, when the required impregnation conditions change, it is not necessary to replace the mold; only the position of the first guide roller A8 within the first impregnation mold head A300 needs to be adjusted. This improves production efficiency and continuity. It also reduces the number of first impregnation mold heads A300, saving production costs.

[0136] Specifically, the inventive concept is to achieve the purpose of adjusting the position of the first guide roller A8 by slotting the inner wall of the mold cavity of the first impregnation mold head A300.

[0137] A first groove A4 is provided on the first inner wall of the first impregnation mold head A300, and the first groove A4 extends between the fiber inlet A1 and the fiber outlet A6 (i.e., Figure 4(As shown in the X-axis direction), the first guide roller A8 moves along the first groove A4 to change its horizontal position within the first impregnation mold head A300.

[0138] Furthermore, a second groove A2 is also provided on the first inner wall of the first impregnation mold head A300, and the second groove extends in a direction perpendicular to the first groove A4 (i.e. Figure 4 (As shown in the Y-axis direction), the first guide roller A8 moves along the second slide groove A2 to change its vertical position in the die head.

[0139] It should be noted that the first groove A4 and the second groove A2 can be connected. Therefore, the first guide roller A8 can move arbitrarily in the longitudinal or transverse direction, thereby changing its position.

[0140] The cross-sections of the first groove A4 and the second groove A2 can be trapezoidal, circular, arc-shaped, or rectangular, etc., and the present invention does not limit them.

[0141] Both ends of the first guide roller A8 are provided with adjustment devices (not shown in the figure). The adjustment devices are used to adjust the axial length of the first guide roller A8. The minimum axial length of the first guide roller A8 is less than the distance between the first inner wall and the second inner wall, and the maximum axial length of the first guide roller A8 is greater than the distance between the first inner wall and the second inner wall.

[0142] like Figure 5 As shown, in another embodiment of the present invention, the second impregnation mold is a combined impregnation mold, including a second impregnation mold head B300. The second impregnation mold head B300 includes a first module B3, an intermediate module B6, and a second module B7 connected in sequence. The first module B3 is provided with a fiber inlet B1 and a first module flow channel B31, the second module B7 is provided with a fiber outlet B8 and a second module flow channel B71, and the intermediate module B6 is provided with an intermediate module flow channel B61.

[0143] After sequentially connecting the first module B3, intermediate module B6, and second module B7, the first module flow channel B31, intermediate module flow channel B61, and second module flow channel B71 are connected to form a combined flow channel B4 for the fiber to pass through. The number of intermediate modules B6 is at least one. That is, the first module B3 is the head module, the second module B7 is the tail module, and there are one or more intermediate modules B6 between them. It should be noted that these intermediate modules B6 are also sequentially connected.

[0144] In other words, the number of intermediate modules B6 can be increased or decreased as needed, so that when the impregnation requirements change, different intermediate modules B6 can be combined to form a combined second impregnation mold head B300, thereby improving production continuity and efficiency and saving the cost of additional mold opening.

[0145] Furthermore, by selecting different intermediate modules B6, the shape parameters (such as curvature) of the combined flow channel B4 can be changed, thereby altering the flow path of the fiber and melt. This allows for changes in the impregnation angle and fiber tension at different stations in the mold, ultimately achieving the goal of adjusting and optimizing the entire impregnation process and improving the adaptability of the second impregnation mold head B300 to polyamide resin and fiber.

[0146] The first module B3, the intermediate module B6, and the second module B7 are placed in the mold frame. The mold frame provides a constraint, ensuring that they are in close contact with each other and thus guaranteeing the sealing of the combined flow channel B4.

[0147] like Figure 5 As shown, an implementation with two intermediate modules B6 is illustrated. Figure 5 In the embodiment shown, the downstream end of the first module flow channel B31 is connected to the upstream end of one of the intermediate module flow channels B61, the two intermediate module flow channels B61 are connected to each other, and the downstream section of the other intermediate module flow channel B61 is connected to the upstream end of the second intermediate module flow channel B71, thereby forming a combined flow channel B4 extending from the fiber inlet B1 to the fiber outlet B8.

[0148] Understandably, different combinations of flow channels B4 can be obtained by selecting different intermediate modules B6.

[0149] like Figure 5 As shown, the downstream end of the first module flow channel B31, the upstream end of the second module flow channel B71, and both ends of the intermediate module flow channel B61 are all located in the same plane and are constructed with standardized connectors B5. In other words, the connections between the first module flow channel B31, the intermediate module flow channel B61, and the second module B71 are made through standardized connectors B5. Since the standardized connectors B5 are all located in the same plane and have the same shape and size, it facilitates the combination and connection between different modules.

[0150] like Figure 6 As shown, in another embodiment of the present invention, the third impregnation mold is a strong turbulent impregnation mold, including a third impregnation mold head C300. The third impregnation mold head C300 includes an impregnation mold outer body C2. The impregnation mold outer body C2 is provided with a fiber inlet channel C3, an impregnation outlet C6, and a melt gap flow channel C1. The fiber inlet channel C3, the impregnation outlet C6, and the melt gap flow channel C1 are all connected to the mold cavity inside the impregnation mold outer body C2.

[0151] The impregnation mold body C2 has a second guide roller inside its cavity. This second guide roller includes at least one active guide roller C4, which is driven to rotate by a drive device (not shown in the figure). Since the rotation of the active guide roller C4 is driven by the drive device, rather than by the fiber's traction, the actively rotating active guide roller C4 helps reduce the fiber's traction tension and the friction between the fiber and the active guide roller C4 as the fiber passes through it. This reduces fiber breakage, ensures fiber integrity, and prevents fiber breakage, thereby improving the material's mechanical properties.

[0152] Preferably, the second guide roller further includes at least one driven guide roller C5, which is driven by the fiber passing through the active guide roller C4; or the driven guide roller C5 and the active guide roller C4 are connected by a belt mechanism, a gear mechanism or a chain mechanism.

[0153] like Figure 6 The diagram illustrates an example with one active guide roller C4 and two driven guide rollers C5, wherein the two driven guide rollers C5 are arranged one above the other to extend the impregnation path of the fibers passing through them. The active guide roller C4 and the driven guide rollers C5 may be at the same or different heights within the die cavity.

[0154] Furthermore, the driving device can be a motor, hydraulic mechanism, or gearbox, or any device capable of driving the active guide roller C4 to rotate.

[0155] Based on the fiber's traveling speed v1 in the mold cavity of the impregnation mold body C2, the corresponding tangential speed v2 of the active guide roller C4 can be selected. For example, the tangential speed v2 of the active guide roller C4 can be made the same as the fiber's traveling speed v1, i.e., v1 = v2. This reduces fiber breakage and wear, thus ensuring fiber integrity, promoting the degree of fiber impregnation, shortening impregnation time, and improving production efficiency.

[0156] like Figure 2 As shown, the melt plasticizing feeding device 4 consists of a twin-screw extruder used for melting and plasticizing materials. The twin-screw extruder is a co-rotating twin-screw extruder with a screw diameter of 25mm-95mm and a length-to-diameter ratio of 36:1-65:1. When the melt plasticizing feeding device 4 consists of a single extruder 4, the melt plasticizing material in the extruder is divided by a melt distributor and fed into the impregnation die and the forming die respectively, and the flow rate of each die is controlled by a melt flow control valve.

[0157] like Figure 3As shown, when the melt plasticizing feeding device 4 consists of two extruders 4-1 and 4-2, the molten plasticized melts from extruder I 4-1 and extruder II 4-2 are respectively fed into the impregnation mold and the forming mold. In this embodiment, the melt plasticizing feeding device consists of two extruders I 4-1 and extruder II 4-2, and the molten plasticized melts from extruder I 4-1 and extruder II 4-2 are respectively fed into the first impregnation mold 3 and the forming mold 5. Extruder I 4-1 and extruder II 4-2 can be fed with the same or different materials, thus enabling the preparation of composite materials with the same or different materials for the inner and outer layers.

[0158] The fiber pretreatment device 2 consists of a tension roller and a hot drying tunnel. This combination allows for some release of tension on the fibers as they enter the hot drying tunnel, thus accommodating fibers of different strengths and preventing fibers with lower strength from breaking before entering the impregnation die. The surface of the tension roller in the fiber pretreatment device 2 needs to be ceramic-coated to increase surface roughness and reduce friction on the fibers.

[0159] In the manufacturing system, the fiber frame and fiber guiding device 1 are used for fiber output and untwisting. The device is equipped with an automatic control untwisting device, which is linked with the traction machine 8 and electrically connected to the electrical control system (such as a PLC control device).

[0160] In the manufacturing system, the cooling water tank 6, dryer 7, traction machine 8, pelletizer 9, and collection box 10 are conventional equipment or devices known to those skilled in the art, and will not be described in detail here.

[0161] Figure 7 A schematic diagram showing the second impregnation process using a molding die is shown. Figure 8 A cross-sectional view of the molding die used in the second impregnation process is shown.

[0162] like Figure 8 As shown, in one embodiment, the molding die 5 consists of a core 5-1, an outer sleeve 5-2, and an outer sleeve opening template 5-3. The core 5-1 is located inside the outer sleeve 5-2, forming a cavity with the outer sleeve 5-2. The resin melt can enter the cavity from the bottom, top, or both sides of the outer sleeve 5-2. The core 5-1 can move back and forth within the outer sleeve 5-2, and the pressure of the melt in the cavity is determined by adjusting the size of the formed cavity space. The pressure of the melt in the cavity can also be adjusted by the angle between the core 5-1 and the outer sleeve 5-2. The working principle of the molding die 5 is as follows: the strip of inner impregnated material formed after passing through the impregnation mold 3 is guided through the hole in the middle of the core 5-1, and then the composite structure of the inner and outer layer materials is formed in the cavity filled with mixed melt formed by the core 5-1 and the outer sleeve 5-2. Finally, it is discharged through the outer sleeve opening template 5-3.

[0163] like Figure 7 As shown, the material strip 5-4 enters the cavity filled with the second component melt formed by the core (not shown) and the outer sleeve 5-2 for processing, wherein the second component melt is fed into the cavity from the second resin inlet 5-5.

[0164] In the following embodiments and comparative examples, the following methods are employed: Figure 3 The manufacturing system shown prepares toughened modified thermally conductive polyamide composites, wherein the first impregnation treatment is selected from... Figure 4 The first immersion mold shown, the second immersion treatment uses Figure 8 The molding die shown.

[0165] The toughened modified thermally conductive polyamide composite material and its preparation method provided by the present invention will be described in detail below with reference to specific embodiments.

[0166] Unless otherwise defined, the technical terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art. Unless otherwise specified, the reagents used in the following embodiments are conventional biochemical reagents; the raw materials, instruments, and equipment used in the following embodiments can all be obtained commercially or by existing methods; unless otherwise specified, the reagent dosages are those used in routine experimental operations; unless otherwise specified, the experimental methods are conventional methods.

[0167] In the various embodiments and comparative examples of the present invention, the testing methods for each performance data are as follows:

[0168] (1) Tensile strength test was conducted in accordance with ISO527-2 standard, with a tensile speed of 5 mm / min.

[0169] (2) The bending strength test was conducted in accordance with ISO178 standard, with a bending speed of 2 mm / min.

[0170] (3) The notched impact strength test shall be conducted in accordance with ISO179 standard.

[0171] (4) Surface gloss test shall be conducted in accordance with ISO2813 standard.

[0172] The materials used in the various embodiments and comparative examples of the present invention are as follows:

[0173] (1) Polyamide resin: PA6-BL3200H, viscosity 2.0, Sinopec Baling Branch.

[0174] (2) Glass fiber: ER4301H, alkali-free glass fiber, diameter 17μm, linear density 2400tex, Chongqing International Composite Materials Co., Ltd.

[0175] (3) Carbon fiber: T700SC, tow 1200-50C, Toray Industries, Japan.

[0176] (4) Maleic anhydride grafted polypropylene (PP-g-MAH): BONDYRAM 1001, Prilang Plastics Industries Ltd.

[0177] (5) Maleic anhydride grafted ethylene-octene copolymer (POE-g-MAH): CMG9805, Shanghai Rizhisheng Technology Co., Ltd.

[0178] (6) Titanate coupling agent: NDZ12, produced by Nanjing Shuguang Chemical Group Co., Ltd.

[0179] (7) Antioxidant 1010, BASF.

[0180] (8) Antioxidant 168, BASF

[0181] (9) Magnesium oxide: 4μm, Yingkou Lixin Magnesium Industry.

[0182] (10) Magnesium hydroxide, 5μm, Hebei Magnesium Sheng Chemical Co., Ltd.

[0183] (11) Aluminum nitride, 10μm, Hunan Jutai Smart New Materials

[0184] (12) Boron nitride, 10 μm, Hunan Jutai Smart New Materials

[0185] (13) Polybutylene adipate terephthalate (PBAT): TH801T, Lanshan Tunhe;

[0186] (14) Polycaprolactone (PCL): 6800, Solvay, USA.

[0187] (15) Mixed toughening agent 1#: hydrogenated nitrile rubber: POE-g-MAH = 80:20 (by weight)

[0188] The preparation method is as follows:

[0189] a. Add 20 parts by weight of POE-g-MAH (CMG9805) to a mixer and melt it at 180°C. Then add 80 parts by weight of hydrogenated nitrile butadiene rubber (99% saturation, 36% acrylonitrile content, Mooney viscosity 65, Zeon Corporation, Japan) and 0.1 parts by weight of antioxidant RD (Ningkang Chemical). Stir at 50 r / min and mix for 5 minutes to obtain modified hydrogenated nitrile butadiene masterbatch.

[0190] b. Modified hydrogenated nitrile butadiene masterbatch was prepared into vulcanized rubber using ordinary rubber processing technology: 100 parts by weight of modified hydrogenated nitrile butadiene masterbatch, 5 parts by weight of zinc oxide (Beijing Inokai), 1 part by weight of stearic acid (Beijing Inokai), 40 parts by weight of N-220 carbon black (Tianjin Baochi Chemical), 1 part by weight of antioxidant RD (Ningkang Chemical), 8 parts by weight of peroxide vulcanizing agent F-40 (Beijing Inokai), and 2 parts by weight of triallyl isocyanate (co-vulcanizing agent, Beijing Inokai) were mixed in an internal mixer and then vulcanized in an ordinary flat vulcanizing machine at 180℃ for 10 minutes.

[0191] c. Vulcanized rubber is physically crushed to obtain mixed toughening agent 1#.

[0192] (16) Mixed toughening agent 2#: hydrogenated nitrile rubber: POE-g-MAH = 50:50 (by weight)

[0193] The preparation method is as follows:

[0194] a. Add 50 parts by weight of POE-g-MAH (CMG9805) to a mixer and melt it at 180°C. Then add 50 parts by weight of hydrogenated nitrile butadiene rubber (99% saturation, 36% acrylonitrile content, Mooney viscosity 65, Zeon Corporation, Japan) and 0.1 parts by weight of antioxidant RD (Ningkang Chemical). Stir at 50 r / min and mix for 5 minutes to obtain modified hydrogenated nitrile butadiene masterbatch.

[0195] b. Modified hydrogenated nitrile butadiene masterbatch was prepared into vulcanized rubber using ordinary rubber processing technology: 100 parts by weight of modified hydrogenated nitrile butadiene masterbatch, 2.5 parts by weight of zinc oxide (Beijing Inokai), 1 part by weight of stearic acid (Beijing Inokai), 25 parts by weight of N-220 carbon black (Tianjin Baochi Chemical), 1 part by weight of antioxidant RD (Ningkang Chemical), 5 parts by weight of peroxide vulcanizing agent F-40 (Beijing Inokai), and 1.25 parts by weight of triallyl isocyanate (co-vulcanizing agent, Beijing Inokai) were mixed in an internal mixer and then vulcanized in an ordinary flat vulcanizing machine at 180℃ for 10 minutes.

[0196] c. Vulcanized rubber is physically crushed to obtain mixed toughening agent 2#.

[0197] (17) Mixed toughening agent 3#: hydrogenated nitrile rubber: POE-g-MAH = 20:80 (by weight)

[0198] The preparation method is as follows:

[0199] a. Add 80 parts by weight of POE-g-MAH (CMG9805) to a mixer and melt it at 180°C. Then add 20 parts by weight of hydrogenated nitrile butadiene rubber (99% saturation, 36% acrylonitrile content, Mooney viscosity 65, Zeon Corporation, Japan) and 0.1 parts by weight of antioxidant RD (Ningkang Chemical). Stir at 50 r / min and mix for 5 minutes to obtain modified hydrogenated nitrile butadiene masterbatch.

[0200] b. Modified hydrogenated nitrile butadiene masterbatch was prepared into vulcanized rubber using ordinary rubber processing technology: 100 parts by weight of modified hydrogenated nitrile butadiene masterbatch, 1 part by weight of zinc oxide (Beijing Inokai), 0.5 parts by weight of stearic acid (Beijing Inokai), 10 parts by weight of N-220 carbon black (Tianjin Baochi Chemical), 0.5 parts by weight of antioxidant RD (Ningkang Chemical), 2 parts by weight of peroxide vulcanizing agent F-40 (Beijing Inokai), and 0.5 parts by weight of triallyl isocyanate (co-vulcanizing agent, Beijing Inokai) were mixed in an internal mixer and then vulcanized in an ordinary flat vulcanizing machine at 180℃ for 10 minutes.

[0201] c. Vulcanized rubber is physically crushed to obtain mixed toughening agent 3#.

[0202] (18) Hydrogenated butadiene-acrylonitrile rubber:

[0203] The preparation method is as follows:

[0204] Hydrogenated nitrile butadiene rubber (NBR) was prepared using a conventional rubber processing method: 100 parts by weight of hydrogenated NBR masterbatch (99% saturation, 36% acrylonitrile content, Mooney viscosity 65, from Zeon Corporation, Japan), 5 parts by weight of zinc oxide (Beijing Inokai), 1 part by weight of stearic acid (Beijing Inokai), 50 parts by weight of N-220 carbon black (Tianjin Baochi Chemical), 2 parts by weight of antioxidant RD (Ningkang Chemical), 8 parts by weight of peroxide vulcanizing agent F-40 (Beijing Inokai), and 2 parts by weight of triallyl isocyanate (co-vulcanizing agent, Beijing Inokai) were mixed in a Banbury mixer, then vulcanized in a conventional flat vulcanizing machine at 180℃ for 10 minutes, and finally physically crushed to obtain hydrogenated NBR.

[0205] (19) Nylon 66 (PA66), A3W, BASF, Germany;

[0206] (20) Nylon 10T (PA10T), Vicnyl, Kingfa Science & Technology.

[0207] Example 1

[0208] (1) Weigh 57 parts by weight of PA6-BL3200H, 3 parts by weight of POE-g-MAH (CMG9805), 0.1 parts by weight of antioxidant 1010 and 0.1 parts by weight of antioxidant 168, stir them in a high-speed mixer at 50°C for 3 minutes to obtain a melt, and then send it into an impregnation mold.

[0209] (2) 40 parts by weight of continuous glass fiber (ER4301H) enters the impregnation mold under the action of the traction machine, where it is impregnated and dispersed with the melt to form a strip, which is used as the inner layer material.

[0210] (3) Weigh 35 parts by weight of PA6-BL3200H, 36 parts by weight of thermally conductive main material (magnesium oxide with a particle size of 4μm), 4 parts by weight of thermally conductive auxiliary material (aluminum nitride with a particle size of 10μm), 8 parts by weight of mixed toughening agent 1#, 0.1 parts by weight of antioxidant 1010, and 0.1 parts by weight of antioxidant 168. Stir them in a high-speed mixer at 50°C for 3 minutes. Use them as the outer layer material and feed them into a twin-screw extruder connected to the molding die.

[0211] (4) The inner layer material enters the molding die under the action of the traction machine, is guided through the hole in the middle of the core, and is formed in the cavity filled with the molten mixture of the outer layer material formed by the core and the outer jacket. Finally, it is exported through the outer jacket template.

[0212] (5) Adjust the amount of outer layer material by selecting the size of the outer mold outer template (6mm), and adjust the cutting speed of the pelletizer so that the pellet length of the prepared composite material is controlled to be 12mm.

[0213] (6) The toughened modified thermally conductive polyamide composite material prepared by the above method was injection molded into standard specimens and its performance was tested. The test results are shown in Table 2.

[0214] Comparative Example 1

[0215] (1) 57 parts by weight of PA6-BL3200H, 3 parts by weight of POE-g-MAH (CMG9805), 0.1 parts by weight of antioxidant 1010 and 0.1 parts by weight of antioxidant 168 were stirred in a high-speed mixer at 50°C for 3 minutes; 40 parts by weight of glass fiber (25mm) were added and stirred in a high-speed mixer at 50°C for 3 minutes.

[0216] (2) 35 parts by weight of PA6-BL3200H, 36 parts by weight of thermally conductive main material (magnesium oxide with a particle size of 4μm), 4 parts by weight of thermally conductive auxiliary material (aluminum nitride with a particle size of 10μm), 8 parts by weight of mixed toughening agent 1#, 0.1 parts by weight of antioxidant 1010 and 0.1 parts by weight of antioxidant 168 are stirred in a high-speed mixer at 50°C for 3 minutes.

[0217] (3) The two mixtures were added together into a twin-screw extruder for melt granulation, and the resulting polyamide composite material particles were 12 mm in length.

[0218] (4) The polyamide composite material prepared above was injection molded into standard specimens and its performance was tested. The test results are shown in Table 2.

[0219] Comparative Example 2

[0220] (1) 57 parts by weight of PA6-BL3200H, 3 parts by weight of POE-g-MAH (CMG9805), 0.1 parts by weight of antioxidant 1010 and 0.1 parts by weight of antioxidant 168 were stirred in a high-speed mixer at 50°C for 3 minutes; 40 parts by weight of glass fiber (25 mm) were added and stirred in a high-speed mixer at 50°C for 3 minutes, and then melt granulation was carried out to obtain polyamide composite material 1.

[0221] (2) 35 parts by weight of PA6-BL3200H, 36 parts by weight of thermally conductive main material (magnesium oxide with a particle size of 4μm), 4 parts by weight of thermally conductive auxiliary material (aluminum nitride with a particle size of 10μm), 8 parts by weight of mixed toughening agent 1#, 0.1 parts by weight of antioxidant 1010 and 0.1 parts by weight of antioxidant 168 were stirred in a high-speed mixer at 50°C for 3 minutes, and then melt-granulated to obtain polyamide composite material 2.

[0222] (3) Add polyamide composite material 1 and polyamide composite material 2 together into a twin-screw extruder for melt granulation. The resulting polyamide composite material particles are 12 mm long.

[0223] (4) The polyamide composite material prepared above was injection molded into standard specimens and its performance was tested. The test results are shown in Table 2.

[0224] Example 2

[0225] (1) Weigh 57 parts by weight of PA66, 3 parts by weight of POE-g-MAH (CMG9805), 0.1 parts by weight of antioxidant 1010 and 0.1 parts by weight of antioxidant 168, stir them in a high-speed mixer at 50°C for 3 minutes to obtain a melt, and send it into an impregnation mold.

[0226] (2) Continuous glass fiber (ER4301H) enters the impregnation mold under the action of the traction machine, where it is impregnated and dispersed with the melt to form a strip, which is used as the inner layer material.

[0227] (3) Weigh 35 parts by weight of PA66, 36 parts by weight of thermally conductive main material (20 parts by weight of 4μm particle size magnesium oxide and 16 parts by weight of 5μm particle size magnesium hydroxide), 4 parts by weight of thermally conductive auxiliary material (10μm particle size aluminum nitride), 10 parts by weight of mixed toughening agent 2#, 0.1 parts by weight of antioxidant 1010 and 0.1 parts by weight of antioxidant 168, stir them in a high-speed mixer at 50°C for 3 minutes, use them as the outer layer material, and feed them into a twin-screw extruder connected to the molding die.

[0228] (4) The inner layer material enters the molding die under the action of the traction machine, is guided through the hole in the middle of the core, and is formed in the cavity filled with the molten mixture of the outer layer material formed by the core and the outer jacket. Finally, it is exported through the outer jacket template.

[0229] (5) Adjust the amount of outer layer material by selecting the size of the outer mold outer template (6mm), and adjust the cutting speed of the pelletizer so that the pellet length of the prepared composite material is controlled to be 12mm.

[0230] (6) The toughened modified thermally conductive polyamide composite material prepared by the above method was injection molded into standard specimens and its performance was tested. The test results are shown in Table 2.

[0231] Example 3

[0232] (1) Weigh 57 parts by weight of PA10T, 3 parts by weight of PP-g-MAH (BONDYRAM 1001), 0.5 parts by weight of titanate coupling agent (NDZ12), 0.1 parts by weight of antioxidant 1010, and 0.1 parts by weight of antioxidant 168. Stir in a high-speed mixer at 50°C for 3 minutes to obtain a melt, and then send it into an impregnation mold.

[0233] (2) Continuous carbon fiber (T700SC) enters the impregnation mold under the action of the traction machine, where it is impregnated and dispersed with the melt to form a strip, which is used as the inner layer material.

[0234] (3) Weigh 35 parts by weight of PA10T, 36 parts by weight of thermally conductive main material (24 parts by weight of 4μm particle size magnesium oxide and 12 parts by weight of 5μm particle size magnesium hydroxide), 4 parts by weight of thermally conductive auxiliary material (10μm particle size boron nitride), 10 parts by weight of mixed toughening agent 3#, 0.1 parts by weight of antioxidant 1010 and 0.1 parts by weight of antioxidant 168, stir them in a high-speed mixer at 50°C for 3 minutes, use them as the outer layer material, and feed them into a twin-screw extruder connected to the molding die.

[0235] (4) The inner layer material enters the molding die under the action of the traction machine, is guided through the hole in the middle of the core, and is formed in the cavity filled with the molten mixture of the outer layer material formed by the core and the outer jacket. Finally, it is exported through the outer jacket template.

[0236] (5) Adjust the amount of outer layer material by selecting the size of the outer mold outer template (6mm), and adjust the cutting speed of the pelletizer so that the pellet length of the prepared composite material is controlled to be 12mm.

[0237] (6) The toughened modified thermally conductive polyamide composite material prepared by the above method was injection molded into standard specimens and its performance was tested. The test results are shown in Table 2.

[0238] Example 4

[0239] The preparation process was the same as in Example 1, except that the 36 parts by weight of the thermally conductive main material (magnesium oxide with a particle size of 4 μm) and 4 parts by weight of the thermally conductive auxiliary material (aluminum nitride with a particle size of 10 μm) added in step (3) were replaced with 40 parts by weight of the thermally conductive main material (magnesium oxide with a particle size of 4 μm). The polyamide composite material was then injection molded into standard specimens for performance testing. The test results are shown in Table 2.

[0240] Example 5

[0241] The preparation process was the same as in Example 1, except that 8 parts by weight of mixed toughening agent 1# were not added in step (3). The polyamide composite material was then injection molded into standard specimens for performance testing. The test results are shown in Table 2.

[0242] Example 6

[0243] The preparation process was the same as in Example 1, except that the 8 parts by weight of mixed toughening agent 1# added in step (3) were replaced with 8 parts by weight of hydrogenated butadiene-acrylonitrile rubber. The polyamide composite material was then injection molded into standard specimens for performance testing. The test results are shown in Table 2.

[0244] Example 7

[0245] The preparation process was the same as in Example 1, except that the 8 parts by weight of mixed toughening agent 1# added in step (3) were replaced with 8 parts by weight of POE-g-MAH (CMG9805). The polyamide composite material was then injection molded into standard specimens for performance testing. The test results are shown in Table 2.

[0246] Example 8

[0247] The preparation process was the same as in Example 1, except that the 8 parts by weight of mixed toughening agent 1# added in step (3) were replaced with 8 parts by weight of polybutylene adipate terephthalate (PBAT). The polyamide composite material was then injection molded into standard specimens for performance testing. The test results are shown in Table 2.

[0248] Example 9

[0249] The preparation process was the same as in Example 1, except that the 8 parts by weight of mixed toughening agent 1# added in step (3) were replaced with 8 parts by weight of polycaprolactone (PCL). The polyamide composite material was then injection molded into standard specimens for performance testing. The test results are shown in Table 2.

[0250] Example 10

[0251] The preparation process was the same as in Example 1, except that the 8 parts by weight of mixed toughening agent 1# added in step (3) were replaced with 8 parts by weight of mixed toughening agent 2#. The polyamide composite material was then injection molded into standard specimens for performance testing. The test results are shown in Table 2.

[0252] Example 11

[0253] The preparation process was the same as in Example 1, except that the 8 parts by weight of mixed toughening agent 1# added in step (3) were replaced with 8 parts by weight of mixed toughening agent 3#. The polyamide composite material was then injection molded into standard specimens for performance testing. The test results are shown in Table 2.

[0254] Comparative Example 3

[0255] The preparation process is the same as in Example 1, except that: in step (1), 36 parts by weight of thermally conductive main material (magnesium oxide with a particle size of 4 μm), 4 parts by weight of thermally conductive auxiliary material (aluminum nitride with a particle size of 10 μm) and 8 parts by weight of mixed toughening agent 1# are added; in step (3), the above components are not added again, and the polyamide composite material is injection molded into standard specimens for performance testing. The test results are shown in Table 2.

[0256] Comparative Example 4

[0257] The preparation process is the same as in Example 1, except that: in step (1), 18 parts by weight of thermally conductive main material (magnesium oxide with a particle size of 4 μm), 2 parts by weight of thermally conductive auxiliary material (aluminum nitride with a particle size of 10 μm) and 4 parts by weight of mixed toughening agent 1# are added; in step (3), 18 parts by weight of thermally conductive main material (magnesium oxide with a particle size of 4 μm), 2 parts by weight of thermally conductive auxiliary material (aluminum nitride with a particle size of 10 μm) and 4 parts by weight of mixed toughening agent 1# are added, and the polyamide composite material is injection molded into standard specimens for performance testing. The test results are shown in Table 2.

[0258] Comparative Example 5

[0259] The preparation process was the same as in Example 1, except that in step (3), 36 parts by weight of thermally conductive main material (magnesium oxide with a particle size of 4 μm) and 4 parts by weight of thermally conductive auxiliary material (aluminum nitride with a particle size of 10 μm) were not added, and the polyamide composite material was injection molded into standard specimens for performance testing. The test results are shown in Table 2.

[0260] Table 1. Main component ratios of the composite materials in the examples and comparative examples.

[0261]

[0262]

[0263] Table 2 Material Performance Tests for Examples and Comparative Examples

[0264]

[0265] As can be seen from the results of Example 1 and Comparative Examples 1 and 2, the performance of the composite material obtained by directly melting and blending the inner and outer layer materials is significantly lower than that of the polyamide composite material obtained by the preparation method described in this invention. This shows that the technology described in this invention can uniformly disperse a high content of thermally conductive filler and maintain the length of the filler fibers, ultimately resulting in a high-performance thermally conductive polyamide composite material.

[0266] The results of Examples 1 and 4 show that thermally conductive additives not only improve the thermal conductivity of composite materials, but also that the composite toughening system composed of toughening agents and thermally conductive additives can effectively improve the impact performance of thermally conductive polyamide composite materials, especially the low-temperature impact performance.

[0267] The results of Examples 1 and 5-9 show that adding toughening agents to the composite material can improve its room temperature impact resistance and low temperature impact resistance. Compared with other toughening agents, the mixed toughening agent, including maleic anhydride-grafted ethylene-octene copolymer and hydrogenated nitrile rubber, can give the composite material better room temperature impact resistance, low temperature impact resistance and thermal conductivity.

[0268] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A toughened modified thermally conductive polyamide composite material, characterized in that, It includes an inner core material and at least one outer layer material; the inner core material includes a first polyamide resin, fibers, and a first additive, the fibers extending continuously from one end of the inner core material to its opposite end; the outer layer material encapsulates the inner core material, and the outer layer material includes a second polyamide resin, a thermally conductive filler, a toughening agent, and a second additive; In the core material, the amount of the first polyamide resin is 25-70 parts by weight, and the amount of fiber is 20-60 parts by weight. In the outer layer material, the amount of the second polyamide resin is 20-70 parts by weight, the amount of the thermally conductive filler is 25-80 parts by weight, and the amount of the toughening agent is 3-25 parts by weight. The fiber is carbon fiber, glass fiber, or a mixture of both. The thermally conductive filler includes a thermally conductive main material and a thermally conductive auxiliary material. The thermally conductive main material is selected from metal oxides and / or metal hydroxides, and the thermally conductive auxiliary material is selected from inorganic powders. The toughening agent is selected from at least one of polyolefin copolymers, specialty rubbers, biodegradable polyesters, natural rubbers, and bio-based elastomers.

2. The composite material according to claim 1, characterized in that, In the core material, the amount of the first polyamide resin is 25-45 parts by weight; the amount of fiber is 30-50 parts by weight. And / or, in the core material, the weight ratio of fiber to first polyamide resin is (0.5-2):1; And / or, in the outer layer material, the amount of the second polyamide resin is 25-45 parts by weight; the amount of the thermally conductive filler is 30-70 parts by weight; and the amount of the toughening agent is 5-20 parts by weight.

3. The composite material according to claim 1 or 2, characterized in that, The first polyamide resin and the second polyamide resin may be the same or different, and each is independently selected from at least one of aliphatic polyamide, semi-aromatic polyamide, aromatic polyamide and copolyamide and their alloy polymers; And / or, the carbon fiber is at least one of polyacrylonitrile-based carbon fiber, petroleum pitch-based carbon fiber, coal tar pitch-based carbon fiber, viscose-based carbon fiber, phenolic-based carbon fiber, vapor-grown carbon fiber, bacterial cellulose-based carbon fiber, cellulose-based carbon fiber, and lignin-based carbon fiber.

4. The composite material according to claim 3, characterized in that, The first polyamide resin and the second polyamide resin may be the same or different, and each is independently selected from at least one of nylon 6, nylon 66, a mixture of nylon 6 and nylon 66, nylon 1010, nylon 11, nylon 12, nylon 610, nylon 612, nylon 6T and nylon 10T.

5. The composite material according to claim 1 or 2, characterized in that, Based on the total weight of the thermally conductive filler, the content of the main thermally conductive material is 50-98 wt%, and the content of the auxiliary thermally conductive material is 2-50 wt%.

6. The composite material according to claim 1 or 2, characterized in that, The thermally conductive main material is selected from at least one of alumina, antimony trioxide, titanium dioxide, magnesium oxide, aluminum hydroxide, and magnesium hydroxide. And / or, the particle size of the thermally conductive main material is 1-100 μm; And / or, the inorganic powder is selected from at least one of carbon nanotubes, carbon black, flake graphite, graphene, boron nitride, boron carbide, aluminum nitride, and silicon carbide; And / or, the particle size of the inorganic powder is 1~100μm.

7. The composite material according to claim 6, characterized in that, The thermally conductive main material is selected from at least one of alumina, magnesium oxide, aluminum hydroxide, and magnesium hydroxide; And / or, the particle size of the thermally conductive main material is 1-40 μm; And / or, the inorganic powder is selected from at least one of boron nitride, aluminum nitride, and silicon carbide.

8. The composite material according to claim 1 or 2, characterized in that, The toughening agent is selected from at least one of polybutylene adipate, polybutylene terephthalate, polybutylene succinate and its copolymers, polyhydroxy fatty acids, polycaprolactone, natural rubber, ethylene-octene copolymers and their modifications, hydrogenated nitrile butadiene rubber, and functionalized solution-polymerized styrene-butadiene.

9. The composite material according to claim 8, characterized in that, The toughening agent is selected from at least one of polybutylene adipate terephthalate, polybutylene terephthalate succinate, ethylene-octene copolymer and its maleic anhydride modified form, and hydrogenated nitrile rubber.

10. The composite material according to claim 9, characterized in that, The toughening agent is a maleic anhydride modified from ethylene-octene copolymer and hydrogenated nitrile rubber.

11. The composite material according to claim 10, characterized in that, The weight ratio of the maleic anhydride modified ethylene-octene copolymer to the hydrogenated nitrile rubber is 0.2 to 5.

12. The composite material according to claim 1 or 2, characterized in that, The first additive comprises at least one of 0.3-15 parts by weight of a first compatibilizer, 0.1-3 parts by weight of a first antioxidant, and 0.5-1 parts by weight of a first lubricant; And / or, the second additive includes at least one of 0.3-15 parts by weight of a second compatibilizer, 0.1-3 parts by weight of a second antioxidant, and 0.5-1 parts by weight of a second lubricant.

13. The composite material according to claim 12, characterized in that, The first additive comprises at least one of 1-5 parts by weight of a first compatibilizer, 0.1-1 parts by weight of a first antioxidant, and 0.5-1 parts by weight of a first lubricant; And / or, the second additive comprises at least one of 1-5 parts by weight of a second compatibilizer, 0.1-1 parts by weight of a second antioxidant, and 0.5-1 parts by weight of a second lubricant.

14. The composite material according to claim 12, characterized in that, The first compatibilizer and the second compatibilizer may be the same or different, and each is independently selected from at least one of maleic anhydride-grafted polypropylene, maleic anhydride-grafted ethylene-octene copolymer, titanate coupling agent and aluminate coupling agent. And / or, the first antioxidant and the second antioxidant may be the same or different, each independently selected from at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris[2,4-di-tert-butylphenyl] phosphite, octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane and bis(2,4-di-tert-butylphenol) pentaerythritol diphosphite; And / or, the first lubricant and the second lubricant may be the same or different, each independently selected from at least one of ethylene bis-stearamide, calcium stearate, polyethylene wax and pentaerythritol stearate.

15. The composite material according to claim 1 or 2, characterized in that, The core material does not contain non-oriented short fibers.

16. The composite material according to claim 15, characterized in that, The core material is composed of a first polyamide resin, fibers, and a first additive.

17. A method for preparing the composite material according to any one of claims 1-16, characterized in that, include: S1. The first polyamide resin and the first additive are mixed and melted to obtain the first component melt; S2. The continuous fibers are subjected to a first impregnation treatment with the first component melt in step S1 to form a filamentous core material; S3. The second polyamide resin, thermally conductive filler, toughening agent and second additive are mixed and melted to obtain the second component melt; S4. The core material obtained in step S2 is subjected to at least one second impregnation treatment with at least one second component melt obtained in step S3 to obtain a toughened modified thermally conductive polyamide composite material.

18. The preparation method according to claim 17, characterized in that, The mixing conditions for step S1 are: temperature of 40-60℃, time of 3-5 min; and / or the melting temperature of step S1 is 220-380℃. And / or, the mixing conditions in step S3 are: temperature of 40-60℃, time of 3-5 min; and / or the melting temperature in step S3 is 220-380℃; And / or, step S2 further includes: dispersing and preheating the continuous fibers before subjecting them to the first impregnation treatment; And / or, step S4 further includes: after the second impregnation treatment, performing pull-out, strip-drawing, cooling, drying, and pelletizing treatment on the material obtained by the second impregnation treatment to obtain a toughened modified thermally conductive polyamide composite material.

19. The preparation method according to claim 18, characterized in that, The preheating temperature is 80-250℃.

20. The preparation method according to any one of claims 17-19, characterized in that, In step S2, the first impregnation process is performed in a first impregnation mold. The first impregnation mold is an adjustable impregnation mold, which includes a fiber inlet, a fiber outlet, and a melt flow channel. At least one first guide roller is provided in the mold cavity of the first impregnation mold. The first guide roller is movable between the fiber inlet and the fiber outlet. And / or, the first guide roller is movable along a direction perpendicular to the line connecting the fiber inlet and the fiber outlet.

21. The preparation method according to any one of claims 17-19, characterized in that, In step S2, the first impregnation process is carried out in the second impregnation mold. The second impregnation mold is a combined impregnation mold, which includes a first module, an intermediate module, and a second module connected in sequence. The first module is provided with a fiber inlet and a first module flow channel. The second module is provided with a fiber outlet and a second module flow channel. The intermediate module is provided with an intermediate module flow channel. After the first module, the intermediate module, and the second module are connected in sequence, the first module flow channel, the intermediate module flow channel, and the second module flow channel are connected to form a combined flow channel for the fiber to pass through.

22. The preparation method according to any one of claims 17-19, characterized in that, In step S2, the first impregnation process is carried out in a third impregnation mold. The third impregnation mold is a strong turbulent impregnation mold. The third impregnation mold includes a fiber inlet channel, an impregnation outlet, and a melt gap channel. The fiber inlet channel, the impregnation outlet, and the melt gap channel are all connected to the mold cavity inside the third impregnation mold. A second guide roller is provided inside the mold cavity of the third impregnation mold. The second guide roller includes at least one active guide roller, which is driven to rotate by a driving device.

23. The application of the composite material according to any one of claims 1-16 or the composite material prepared by the preparation method according to any one of claims 17-22 in the fields of automotive industry, machinery manufacturing, electronics and electrical appliances, chemical and environmental protection, aerospace and communications and construction industry.

24. The application according to claim 23, characterized in that, The application is in large automotive parts and / or high-precision electronic and electrical components.

25. The application according to claim 23, characterized in that, The application is in the automotive front-end module and / or the all-plastic tailgate inner panel.

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