Nylon composition as well as preparation method and application thereof

Abstract

The invention discloses a nylon composition as well as a preparation method and application thereof, and relates to the technical field of high polymer materials. The invention provides a nylon composition. The nylon composition comprises the following components in parts by weight: 20-70 parts of nylon resin, 3-15 parts of glass fibers, 30-60 parts of crystalline flake graphite, 0.5-6 parts of petroleum resin and 0.2-0.8 part of a silane coupling agent, the apparent density of the crystalline flake graphite is greater than or equal to 0.8 g / mL, and the mesh number of the crystalline flake graphite is 200-1000. The nylon resin, the glass fiber, the crystalline flake graphite, the petroleum resin and other components cooperate with one another, so that the processability is better, and the prepared nylon composition is better in appearance and heat-conducting property.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a nylon composition, its preparation method, and its application. Background Technology

[0002] As electronic and electrical equipment becomes smaller and more integrated, the energy density and output power of energy storage devices continue to increase, making thermal management a crucial aspect of ensuring efficient and safe operation. Heat dissipation materials must simultaneously meet requirements for thermal conductivity, appearance quality, and mechanical strength, and are widely used in electronics, automobiles, and other fields. While traditional metal heat dissipation materials offer excellent thermal conductivity, they suffer from drawbacks such as heavy weight, complex processing, and high cost. Thermally conductive nylon (PA), with its advantages of low density, ease of processing, and high design freedom, has become an important direction for replacing aluminum with plastics; however, its overall performance still falls short of meeting the stringent requirements of high-end heat dissipation scenarios. Currently, most thermally conductive nylons on the market use high filler content (approximately 50%) to construct the thermally conductive network, leading to deterioration in material processing performance: difficulty in stringing during extrusion granulation, poor flowability during final injection molding, and appearance defects such as flow marks and silver streaks in the finished products; at the same time, the high filler content limits the improvement of thermal conductivity. While existing technologies have improved interfacial bonding through methods such as coupling agent modification, they have not fundamentally resolved the contradiction between high filler content and processing performance, failing to simultaneously meet the comprehensive requirements of high thermal conductivity and good appearance, thus restricting the application of thermally conductive nylon in high-end heat dissipation fields.

[0003] Therefore, the poor processing performance, poor appearance, and low upper limit of thermal conductivity of thermally conductive nylon remain technical challenges that urgently need to be addressed in this field. Summary of the Invention

[0004] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a nylon composition with good appearance, high thermal conductivity and excellent processing performance, as well as its preparation method and application.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a nylon composition comprising the following components in parts by weight: 20-70 parts nylon resin, 3-15 parts glass fiber, 30-60 parts flake graphite, 0.5-6 parts petroleum resin, and 0.2-0.8 parts silane coupling agent; wherein the loose bulk density of the flake graphite is ≥0.8 g / mL, and the mesh size of the flake graphite is 200-1000 mesh.

[0006] Preferably, the nylon resin has a weight percentage of not less than 20% based on the total weight of the nylon composition.

[0007] The addition of petroleum resin in this invention has two advantages. First, petroleum resin is a small molecule with short chain segments. When added to PA resin, it can intercalate within the PA molecular chains, reducing friction between molecular chains and providing good lubrication. This slows down the crystallization rate of nylon, thereby significantly improving the melt flowability and processing performance of the material. Second, petroleum resin has a low melting point. After melting, it can coat the surface of flake graphite, further reducing friction between the flake graphite flakes and promoting dispersion. The flake graphite described in this invention has a high thermal conductivity, above 150 W / (m·K). This invention further limits the loose packing density and mesh size of the flake graphite. The inventors have found that flake graphite under the above-defined limits can achieve a high proportion of filling during feeding, synergistically with components such as petroleum resin, resulting in better processing performance, and the prepared nylon composition has better appearance and thermal conductivity.

[0008] Preferably, the nylon composition comprises the following components in parts by weight: 40-50 parts nylon resin, 8-12 parts glass fiber, 40-50 parts flake graphite, 2-4 parts petroleum resin, and 0.3-0.6 parts silane coupling agent.

[0009] Optionally, the nylon resin is in the range of 20 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 61 parts, 65 parts, 68 parts, and 70 parts by weight, or any two of these values; the glass fiber is in the range of 3 parts, 5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, 9.5 parts, 10 parts, 12 parts, and 15 parts by weight, or any two of these values; the flake graphite... The weight parts are 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, or any two of these values; the weight parts of the petroleum resin are 0.5 parts, 1 part, 2 parts, 3 parts, 4 parts, 4.5 parts, 5 parts, 6 parts, or any two of these values; the weight parts of the silane coupling agent are 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, or any two of these values.

[0010] Preferably, the loose packing density of the flake graphite is 1-1.6 g / mL, and the mesh size of the flake graphite is 500-700 mesh.

[0011] Optionally, the loose packing density of the flake graphite is one or any two of the following: 0.8 g / mL, 1.0 g / mL, 1.2 g / mL, 1.5 g / mL, 1.8 g / mL, and 2.0 g / mL; optionally, the loose packing density of the thermally conductive filler flake graphite is obtained by testing using the vibrating sieve method in GB / T 31057.1-2014.

[0012] Optionally, the mesh size of the flake graphite is one or any two of the following: 200 mesh, 300 mesh, 400 mesh, 500 mesh, 600 mesh, 700 mesh, 800 mesh, and 1000 mesh; optionally, the mesh size of the flake graphite is obtained by testing according to the ISO 13320 laser diffraction particle size analysis method.

[0013] Preferably, the flake graphite with a bulk density ≥ 0.8 g / mL is obtained by pressing. The mesh size of the flake graphite remains almost unchanged before and after pressing.

[0014] Preferably, the petroleum resin is at least one of the following: aliphatic resin (C5) and its maleic anhydride graft, alicyclic resin (DCPD) and its maleic anhydride graft, aromatic resin (C9) and its maleic anhydride graft, aliphatic / aromatic copolymer resin (C5 / C9) and its maleic anhydride graft, hydrogenated C5 petroleum resin, and hydrogenated C9 petroleum resin.

[0015] Preferably, the petroleum resin is at least one of hydrogenated C5 petroleum resin and hydrogenated C9 petroleum resin.

[0016] Preferably, the nylon resin is at least one of nylon 6, nylon 66, nylon 56, nylon 610, nylon 1010 or nylon 12; and / or, the relative viscosity of the nylon resin is 1.5-2.5; the relative viscosity of the nylon resin is measured according to ISO 307:2007 standard.

[0017] Preferably, the silane coupling agent is at least one of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimeth(eth)oxysilane.

[0018] Preferably, the glass fiber is chopped alkali-free glass fiber; and / or, the glass fiber has an average length of 50-600 μm and an average diameter of 8-15 μm.

[0019] Optionally, the glass fiber is tested as follows: the sample is calcined in a muffle furnace at 650°C for 1 h to obtain ash, which is then dispersed in water and observed and tested with an optical microscope to measure the length and diameter of the glass fibers in the ash. A total of 200 fibers are counted and the average value is taken.

[0020] Preferably, the nylon composition further includes 0.1-3 parts of a processing aid, wherein the processing aid is at least one selected from antioxidants and lubricants. For example, 0.1-1 parts of antioxidant and 0.1-1 parts of lubricant.

[0021] Preferably, the antioxidant is at least one of hindered phenolic antioxidants, hindered amine antioxidants, divalent sulfur antioxidants, and phosphite antioxidants. Specifically, the antioxidant includes, but is not limited to, at least one of N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine (antioxidant 1098), tris[2,4-di-tert-butylphenyl]phosphite (antioxidant 168), and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010).

[0022] Preferably, the lubricant includes at least one of stearate, ethylene acrylate copolymer, or montan ester lubricant.

[0023] Furthermore, the present invention provides a method for preparing the aforementioned nylon composition, comprising the following steps: (1) Weigh each component according to the stated weight proportions; (2) Nylon resin, petroleum resin, processing aid and silane coupling agent are mixed evenly and then added to the main feeding system of a twin-screw extruder. Flake graphite is added to the first side feeding system of the twin-screw double-sided feeding machine and glass fiber is added to the second side feeding system of the twin-screw double-sided feeding machine. After melt blending, the mixture is extruded and granulated to obtain the nylon composition.

[0024] Preferably, the present invention provides a method for preparing the nylon composition, comprising the following steps: (1) Weigh each component according to the stated weight proportions; (2) Nylon resin, petroleum resin and processing aid are mixed evenly and then added to the main feeding system of a twin-screw extruder. Flake graphite with silane coupling agent on its surface is added to the first side feeding system of the twin-screw double-sided feeder. Glass fiber is added to the second side feeding system of the twin-screw double-sided feeder. After melt blending, the mixture is extruded and granulated to obtain the nylon composition.

[0025] Preferably, the flake graphite and silane coupling agent are mixed and then pressed to obtain the flake graphite with the silane coupling agent modified on the surface.

[0026] The pressing pressure is determined based on the loose packing density of the flake graphite, as long as the loose packing density is ≥0.8 g / mL. Optionally, the pressing pressure is 10-300 MPa; the pressing is performed using a roller pressing process.

[0027] Preferably, the set temperature of the melt extrusion is 80-300℃; the screw speed of the extruder for melt extrusion is 250-450 rpm, and the length-to-diameter ratio of the screw is 36-48:1.

[0028] Furthermore, the present invention provides applications of the nylon composition in the fields of electronics, electrical appliances, and automobiles; specifically, the present invention provides applications of the nylon composition in automotive headlight heat dissipation modules, servo motor drive heat dissipation modules, lithium battery brackets, security monitoring cameras, etc.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows: the nylon resin, glass fiber, flake graphite, petroleum resin and other components of the present invention work synergistically, resulting in better processing performance, and the nylon composition prepared has better appearance and thermal conductivity. Detailed Implementation

[0030] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments. The purpose is to provide a detailed understanding of the invention, not to limit it. All other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. Unless otherwise specified, the experimental reagents and instruments designed in the embodiments and comparative examples of this invention are commonly used reagents and instruments, all of which are commercially available. Unless otherwise specified, the experimental methods used in the embodiments and comparative examples are conventional methods; and unless otherwise specified, the raw materials used in parallel experiments are from the same batch.

[0031] The raw materials of this invention will now be further described, but are not limited to the following raw materials: Nylon resin-1: PA6, PA6 J1600, relative viscosity 1.6, polymerization cis; Nylon Resin-2: PA66, PA66 U2500 NC01, relative viscosity 2.0, Invista; Nylon Resin-3: PA6, HY-2500A, relative viscosity 2.5, Haiyang Chemical Fiber; Glass fiber: chopped alkali-free glass fiber, ECS10-03-568H, diameter 10μm, Jushi Group; Petroleum Resin-1: Hydrogenated C5 petroleum resin, Shanghai Tongcheng; Petroleum Resin-2: Maleic Anhydride Grafted C5 Petroleum Resin, Shanghai Tongcheng; Petroleum Resin-3: C9 Petroleum Resin, Shanghai Tongcheng; Silane coupling agent: KH550, γ-aminopropyltriethoxysilane, commercially available; Flake graphite-1: 200 mesh, loose bulk density ≤0.5g / mL, grade 299, manufacturer: Qingdao Fukang; Flake graphite-2: 500 mesh, loose packing density ≤0.5g / mL, grade 599, manufacturer: Qingdao Fukang; Flake graphite-3: 800 mesh, loose density ≤0.5g / mL, grade 899, manufacturer: Qingdao Fukang; Flake graphite-4: 80 mesh, loose packing density ≤0.5g / mL, grade 199, manufacturer: Qingdao Fukang; Flake graphite-5: 1200 mesh, loose bulk density ≤0.5g / mL, grade 1299, manufacturer: Qingdao Fukang; Flake graphite-6: self-made, the loose bulk density of the flake graphite is 0.8 g / mL, and the mesh size of the flake graphite is 200 mesh; The preparation method is as follows: silane coupling agent is added to flake graphite-1, and the flake graphite with silane coupling agent on the surface is obtained by rolling process; the pressing pressure is 80 MPa, and the weight ratio of silane coupling agent to flake graphite is 1:100.

[0032] Flake graphite-7: Self-made flake graphite with a silane coupling agent on its surface, wherein the loose bulk density of the flake graphite is 1.2 g / mL and the mesh size of the flake graphite is 200 mesh; The preparation method is the same as that of flake graphite-6, except that the rolling pressure is different, specifically 200 MPa.

[0033] Flake graphite-8: Self-made flake graphite with a surface modified with a silane coupling agent, wherein the loose bulk density of the flake graphite is 1.5 g / mL and the mesh size of the flake graphite is 200 mesh; The preparation method is the same as that of flake graphite-6, except that the rolling pressure is different, specifically 240 MPa.

[0034] Flake graphite-9: Self-made flake graphite with a surface modified with a silane coupling agent, wherein the loose bulk density of the flake graphite is 1.9 g / mL and the mesh size of the flake graphite is 200 mesh; The preparation method is the same as that of flake graphite-6, except that the rolling pressure is different, specifically 300 MPa.

[0035] Flake graphite-10: Self-made flake graphite with a silane coupling agent on its surface, wherein the loose bulk density of the flake graphite is 0.8 g / mL and the mesh size of the flake graphite is 500 mesh; The preparation method is the same as that of flake graphite-6, except that the flake graphite is selected differently, specifically flake graphite-2.

[0036] Flake graphite-11: Self-made flake graphite with a surface modified with a silane coupling agent, wherein the loose bulk density of the flake graphite is 0.8 g / mL and the mesh size of the flake graphite is 800 mesh; The preparation method is the same as that of flake graphite-6, except that the flake graphite is selected differently, specifically flake graphite-3.

[0037] Flake Graphite-12: Self-made flake graphite without surface modification of silane coupling agent, wherein the loose bulk density of the flake graphite is 0.8 g / mL and the mesh size of the flake graphite is 200 mesh; The preparation method is as follows: flake graphite-1 is pressed by a roll pressing process to obtain the flake graphite; the pressing pressure is 80 MPa.

[0038] Flake graphite-13: Self-made flake graphite with a silane coupling agent on its surface, wherein the loose bulk density of the flake graphite is 0.8 g / mL and the mesh size of the flake graphite is 80 mesh; The preparation method is the same as that of flake graphite-6, except that the flake graphite is selected differently, specifically flake graphite-4.

[0039] Flake graphite-14: Self-made flake graphite with a surface modified with a silane coupling agent, wherein the loose bulk density of the flake graphite is 0.8 g / mL and the mesh size of the flake graphite is 1200 mesh; The preparation method is the same as that of flake graphite-6, except that the flake graphite is selected differently, specifically flake graphite-5.

[0040] Lubricant: Mondan ester, TR044W, commercially available; Antioxidant: A compound of IRGANOX 1098 and Revonox 608 in a 1:1 mass ratio, commercially available.

[0041] Examples and Comparative Examples This invention provides a nylon composition, the components and weight parts of which are shown in Tables 1-2. The preparation method of the nylon composition is as follows: (1) Weigh each component according to the stated weight proportions; (2) Nylon resin, petroleum resin and processing aid are mixed evenly and then added to the main feeding system of a twin-screw extruder. Surface-modified silane coupling agent flake graphite is added to the first side feeding system of the twin-screw double-sided feeding machine. Glass fiber is added to the second side feeding system of the twin-screw double-sided feeding machine. After melt blending, the mixture is extruded and granulated to obtain the nylon composition. The melt extrusion temperatures are as follows: PA66: 100℃-160℃-250℃-250℃-240℃-240℃-230℃-230℃-250℃-260℃; PA6: 80℃-120℃-200℃-200℃-190℃-190℃-180℃-180℃-180℃-200℃-220℃.

[0042] The screw speed of the melt extrusion extruder is 300 rpm, and the length-to-diameter ratio of the screw is 48:1.

[0043] Example 9 provides a nylon composition, the components and weight parts of which are shown in Tables 1-2. The preparation method of the nylon composition is as follows: (1) Weigh each component according to the stated weight proportions; (2) Nylon resin, petroleum resin, processing aids and silane coupling agent are mixed evenly and then added to the main feeding system of a twin-screw extruder. Flake graphite is added to the first side feeding system of the twin-screw double-sided feeding machine and glass fiber is added to the second side feeding system of the twin-screw double-sided feeding machine. After melt blending, the mixture is extruded and granulated to obtain the nylon composition. The process parameters are the same as those in other embodiments.

[0044] Table 1 Table 2 Performance testing (1) Melt flow rate: After drying the nylon compositions prepared in the examples and comparative examples in an oven at 120°C for 4 hours, the melt flow rate was tested according to ISO 1133-1:2022 standard, with PA66 at 280°C / 5Kg and PA6 at 260°C / 5Kg.

[0045] (2) Thermal conductivity test: After drying the nylon compositions prepared in the examples and comparative examples in an oven at 120°C for 4 hours, injection molded 125*13*1.6mm strips, cut 10*10*1.6mm blocks, and tested the thermal conductivity according to ASTM E1461-13 (2022) standard.

[0046] (3) Surface condition: After drying the nylon compositions prepared in the examples and comparative examples in an oven at 120°C for 4 hours, 2.0 mm thick color plates were injection molded. The surface gloss at 60° was tested according to ISO 2813-2014, and the surface condition was observed with the naked eye. Grade 1 is smooth surface with no agglomeration, Grade 2 is smooth surface with a very small amount of agglomeration, and Grade 3 is rough surface with obvious agglomeration.

[0047] Table 3 As can be seen from the table above, the nylon composition prepared in the embodiments of the present invention has good processing performance, and the nylon composition prepared has good appearance and thermal conductivity. The melt flow rate of the nylon composition prepared in the embodiments of the present invention is >6.0g / 10min, the thermal conductivity is ≥8.0W / (m·K), the surface gloss is >50GU, and the surface is smooth when observed with the naked eye.

[0048] As can be seen from Examples 1-3, different nylon resins can simultaneously achieve good appearance and thermal conductivity.

[0049] As can be seen from the comparison of Examples 1, 4-8, and Comparative Examples 1-4, the mesh size and loose packing density of the flake graphite affect the appearance and thermal conductivity of the final nylon composition. When the loose packing density of the flake graphite is 1-1.6 g / mL and the mesh size is 500-700 mesh, the nylon composition exhibits better appearance and thermal conductivity. Specifically, Comparative Example 1 has too low a mesh size, resulting in too small a contact area between the flakes and hindering the formation of proper thermal conductivity pathways; Comparative Example 2 has too high a mesh size, leading to poor dispersion, appearance, and thermal conductivity; and Comparative Examples 3-4, when flake graphite is used directly, exhibit poor processing performance, as well as poor appearance and thermal conductivity.

[0050] As can be seen from the comparison of Examples 1 and Examples 11-13, the appearance and thermal conductivity are better when there are 40-50 parts of nylon resin, 8-12 parts of glass fiber, 40-50 parts of flake graphite, 2-4 parts of petroleum resin and 0.3-0.6 parts of silane coupling agent.

[0051] As can be seen from the comparison of Example 1 and Comparative Examples 5-6, too little petroleum resin results in poor processing performance, while excessive petroleum resin results in better processing performance but poor thermal conductivity.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A nylon composition, characterized in that, The product comprises the following components in parts by weight: 20-70 parts nylon resin, 3-15 parts glass fiber, 30-60 parts flake graphite, 0.5-6 parts petroleum resin, and 0.2-0.8 parts silane coupling agent; wherein the loose bulk density of the flake graphite is ≥0.8 g / mL, and the mesh size of the flake graphite is 200-1000 mesh.

2. The nylon composition according to claim 1, characterized in that, It includes the following components in parts by weight: 40-50 parts nylon resin, 8-12 parts glass fiber, 40-50 parts flake graphite, 2-4 parts petroleum resin, and 0.3-0.6 parts silane coupling agent.

3. The nylon composition according to claim 1, characterized in that, The loose packing density of the flake graphite is 1-1.6 g / mL, and the mesh size of the flake graphite is 500-700 mesh.

4. The nylon composition according to claim 1, characterized in that, The petroleum resin is at least one of the following: aliphatic resin and its maleic anhydride graft, alicyclic resin and its maleic anhydride graft, aromatic resin and its maleic anhydride graft, aliphatic / aromatic copolymer resin and its maleic anhydride graft, hydrogenated C5 petroleum resin, and hydrogenated C9 petroleum resin.

5. The nylon composition according to claim 1, characterized in that, The nylon resin is at least one of nylon 6, nylon 66, nylon 56, nylon 610, nylon 1010 or nylon 12; and / or, the relative viscosity of the nylon resin is 1.5-2.

5.

6. The nylon composition according to claim 1, characterized in that, The glass fiber is a chopped alkali-free glass fiber; and / or, the glass fiber has an average length of 50-600 μm and an average diameter of 8-15 μm.

7. The nylon composition according to claim 1, characterized in that, It also includes 0.1-3 parts of processing aids, wherein the processing aids are at least one of antioxidants and lubricants.

8. A method for preparing a nylon composition according to any one of claims 1-7, characterized in that, Includes the following steps: (1) Weigh each component according to the stated weight proportions; (2) Nylon resin, petroleum resin, processing aid and silane coupling agent are mixed evenly and then added to the main feeding system of a twin-screw extruder. Flake graphite is added to the first side feeding system of the twin-screw double-sided feeding machine and glass fiber is added to the second side feeding system of the twin-screw double-sided feeding machine. After melt blending, the mixture is extruded and granulated to obtain the nylon composition.

9. The application of a nylon composition as described in any one of claims 1-7 in the fields of electronics, electrical appliances, and automobiles.

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