High-thermal-conductivity chemical-resistant flame-retardant polycarbonate composite material and preparation method thereof

Abstract

The invention discloses a high-thermal-conductivity chemical-resistant flame-retardant polycarbonate composite material and a preparation method thereof. The high-thermal-conductivity chemical-resistant flame-retardant polycarbonate composite material is prepared from the following raw materials in parts by weight: 66 to 67 parts of polycarbonate, 20 to 20.5 parts of boron nitride, 3 to 3.05 parts of PTFE (Polytetrafluoroethylene) micro powder, 0.5 to 0.55 part of a silane coupling agent KH-550, 5 to 5.1 parts of a toughening agent S-2030, 2 to 2.05 parts of a toughening agent AX-8900, 0.2 to 0.25 part of a lubricating agent PETS (Polyethylene Terephthalate) P861 and 0.7 to 0.75 part of a lubricating agent MB 50-001. The method has the beneficial effect that the heat conduction efficiency of the composite material is improved.

Description

Technical Field

[0001] The present invention relates to a polycarbonate composite material, in particular to a high-thermal-conductivity, chemical-resistant and flame-retardant polycarbonate composite material and a preparation method thereof. Background Art

[0002] Polycarbonate (PC) is widely used due to its high mechanical strength and excellent electrical insulation properties. However, inherent drawbacks of PC include: 1. Low thermal conductivity (0.2 W / mK), which cannot meet the heat dissipation requirements of high-power devices; 2. Achieving flame retardancy requires the addition of large amounts of brominated flame retardants, sparking environmental and toxicity concerns; 3. High levels of thermally conductive fillers (such as AlN and Al2O3) lead to a sharp drop in toughness and difficulty in processing. Summary of the Invention

[0003] The technical problem to be solved by the present invention is that the thermal conductivity coefficient of existing polycarbonate and its composite materials is poor, and a high thermal conductivity, chemical resistance and flame retardant polycarbonate composite material and a preparation method thereof are provided.

[0004] To address the above technical problems, the present invention provides a technical solution: a highly thermally conductive, chemical-resistant, and flame-retardant polycarbonate composite material. The composite material comprises 66-67 parts by weight of polycarbonate, 20-20.5 parts by weight of boron nitride, 3-3.05 parts by weight of PTFE micropowder, 0.5-0.55 parts by weight of a silane coupling agent, KH-550, 5-5.1 parts by weight of a toughening agent, S-2030, 2-2.05 parts by weight of a toughening agent, AX-8900, 0.2-0.25 parts by weight of a lubricant, PETS P861, and 0.7-0.75 parts by weight of a lubricant, MB50-001. The composite material has at least one beneficial effect: the boron nitride forms a thermally conductive network, improving the thermal conductivity efficiency of the composite material. The silane coupling agent, KH-550, improves the interfacial compatibility and adhesion between the polycarbonate and boron nitride, enhancing the thermal conductivity efficiency (better interfacial contact thermal conductivity) and mechanical properties (e.g., tensile strength, flexural strength, and impact toughness) of the composite material. The dual-toughening system, comprised of tougheners S-2030 and AX-8900, effectively counteracts the brittleness associated with high filler content, improves filler dispersion, and enhances the mechanical properties of the composite material. Specifically, the notched impact strength reaches ≥18 kJ / m², a 300% increase compared to the untoughened system. The triple-lubrication system, comprised of PTFE micropowder, lubricant PETS P861, and lubricant MB50-001, reduces melt viscosity, improves extrusion flow, enhances demolding, and eliminates surface defects in the product. (PTFE micropowder reduces friction, while the combined lubrication of PETS P861 and MB50-001 reduces wear by 40% and demolding force by 35%).

[0005] As a preferred embodiment of a high-thermal-conductivity, chemical-resistant, flame-retardant polycarbonate composite material, its raw materials further include: 0.1-0.15 parts by weight of flame retardant FR-2025 and 0.5-0.55 parts by weight of flame retardant F-535. This advantageous effect is at least in that relatively low addition levels of FR-2025 and F-535 significantly improve the composite's flame retardancy (typically reaching UL94 V-0 rating) and help mitigate potential negative impacts on the composite's electrical properties and thermal stability. This also avoids the toxicity and corrosiveness of brominated flame retardants (RoHS / REACH compliance). PTFE micropowder has an anti-drip synergistic effect with FR-2025 and F-535, forming a fibrous web structure during combustion, completely eliminating melt droplets and preventing secondary ignition.

[0006] As a preferred embodiment of a high-thermal-conductivity, chemical-resistant, and flame-retardant polycarbonate composite material, its raw materials further include: 0.7-0.75 parts by weight of antioxidant 1010 and 0.3-0.35 parts by weight of antioxidant 168. This advantageous effect is at least that the antioxidant system formed by antioxidant 1010 and antioxidant 168 maintains a HDT at 1.82 MPa of ≥115°C and a performance retention rate of >85% after 3000 hours of heat aging.

[0007] As a preferred option for highly thermally conductive, chemically resistant, and flame-retardant polycarbonate composites, the boron nitride is spherical with a particle size of 1-2 μm. This beneficial effect is at least in that it helps form a more effective thermal conductivity network within the matrix while having a relatively less negative impact on melt flow and mechanical properties (especially impact resistance) compared to fillers with other shapes or larger particle sizes. Compared to flake boron nitride, spherical boron nitride provides a larger specific surface area, improving the thermal conductivity efficiency of the composite. Compared to angular boron nitride, spherical boron nitride can increase the melt flow index (330°C / 2.16 kg) by 50%.

[0008] As a preferred embodiment of a high-thermal-conductivity, chemical-resistant, and flame-retardant polycarbonate composite material, its raw materials include: 66 parts by weight of polycarbonate, 20 parts by weight of boron nitride, 0.1 parts by weight of flame retardant FR-2025, 0.5 parts by weight of flame retardant F-535, 3 parts by weight of PTFE micropowder, 0.5 parts by weight of silane coupling agent KH-550, 5 parts by weight of toughening agent S-2030, 2 parts by weight of toughening agent AX-8900, 0.7 parts by weight of antioxidant 1010, 0.3 parts by weight of antioxidant 168, 0.2 parts by weight of lubricant PETS P861, and 0.7 parts by weight of lubricant MB50-001. This embodiment provides at least one beneficial effect of providing a specific embodiment of a high-thermal-conductivity, chemical-resistant, and flame-retardant polycarbonate composite material.

[0009] Another technical solution provided by the present invention is a method for preparing the aforementioned high-thermal-conductivity, chemical-resistant, and flame-retardant polycarbonate composite material, comprising a high-temperature mixing step, a water bath cooling step, and a pelletizing step. This method has at least one beneficial effect: providing a specific embodiment for preparing the high-thermal-conductivity, chemical-resistant, and flame-retardant polycarbonate composite material.

[0010] As a preferred embodiment of the preparation method, in the high-temperature mixing step, the high temperature is 280-285° C. The beneficial effect is at least that each additive is evenly dispersed.

[0011] As a preferred embodiment of the preparation method, vacuum devolatilization is performed during the high-temperature mixing step, which has at least the beneficial effect of removing residual solvents and small molecules.

[0012] As a preferred embodiment of the preparation method, in the water bath cooling step, the water bath temperature is 20-30°C. DETAILED DESCRIPTION

[0013] The present invention will be further described in detail below through specific embodiments. It should be noted that the description of these embodiments is intended to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0014] Example 1: The raw materials for preparing high thermal conductivity, chemical resistance and flame retardant polycarbonate composite materials include: Polycarbonate (Wanhua; Clarnate® A1225) 66 kg; Spherical boron nitride (3M Company; particle size 1 μm) 20 kg; Flame retardant FR-2025 (3M Company; halogen-free flame retardant) 0.1 kg; Flame retardant F-535 (Arichem; sulfonate flame retardant) 0.5 kg; PTFE micropowder (3M Company; polytetrafluoroethylene micropowder) 3 kg; Silane coupling agent KH-550 (Dow Corning; γ-aminopropyltriethoxysilane) 0.5 kg; Toughening agent S-2030 (Mitsubishi Corporation; silicone acrylic rubber impact modifier) ​​5 kg; Toughening agent AX-8900 (Arkema; ​​ethylene acrylate glycidyl methacrylate) 2 kg; Antioxidant 1010 (BASF; pentaerythritol ester) 0.7 kg; Antioxidant 168 (BASF; phosphite antioxidant) 0.3 kg; Lubricant PETS P861 (formerly Corning; pentaerythritol stearate) 0.2 kg; Lubricant MB50-001 (DuPont; silicone masterbatch) 0.7 kg.

[0015] The preparation method of the high thermal conductivity, chemical resistance and flame retardant polycarbonate composite material includes: Step S1, preparing raw materials: providing the raw materials and mixing them in a high-speed mixer (mixing temperature: 60°C). The polycarbonate must be pre-dried before mixing (using a dehumidifying dryer with a dew point of -40°C for 4 hours).

[0016] Step S2, high-temperature mixing and kneading of raw materials: the mixed raw materials are passed through a shallow groove co-rotating twin-screw mixing and extrusion granulation unit for high-temperature mixing at 280° C., in order to evenly disperse the additives.

[0017] Among them, the shallow groove type co-rotating twin-screw compounding extrusion granulation unit has a built-in screw, which includes: high shear zone (kneading block), medium shear zone (reverse thread), and low shear zone (conveying element).

[0018] The screw speed is controlled at 250-350 rpm (highly filled systems require moderate speed increase to enhance dispersion).

[0019] Among them, vacuum devolatilization is required, and the vacuum is turned on with a vacuum degree of -0.08MPa to extract the residual solvent and small molecules.

[0020] Step S3, water bath cooling: the extruded wire is cooled in a water tank at a temperature of 20-30° C. The cooling water in the water tank is filtered through two filters, namely a 200 mesh filter and a 40 μm filter, to ensure that there are no obvious impurities in the water.

[0021] Step S4, pelletizing: After the material strips are dried by a hair dryer, they enter a herringbone knife pelletizer. The pelletizer adjusts the speed to control the particle diameter to about 2-3 mm and the length to 4-6 mm.

[0022] Performance characteristics:

[0023] Comparative Example 1: The raw materials for preparing high thermal conductivity, chemical resistance and flame retardant polycarbonate composite materials include: Polycarbonate (Wanhua; Clarnate® A1225) 69 kg; Spherical boron nitride (3M; particle size 1 μm) 10 kg; Flame retardant FR-2025 (3M Company; halogen-free flame retardant) 0.2 kg; Flame retardant F-535 (Arichem; sulfonate flame retardant) 1 kg; PTFE micropowder (3M Company; polytetrafluoroethylene micropowder) 5 kg; Silane coupling agent KH-550 (Dow Corning; γ-aminopropyltriethoxysilane) 1 kg; Toughening agent S-2030 (Mitsubishi Corporation; silicone acrylic rubber impact modifier) ​​8 kg; Toughening agent AX-8900 (Arkema; ​​ethylene acrylate glycidyl methacrylate) 3 kg; Antioxidant 1010 (BASF; pentaerythritol ester) 1 kg; Antioxidant 168 (BASF; phosphite antioxidant) 0.5 kg; Lubricant PETS P861 (formerly Corning; pentaerythritol stearate) 0.5 kg; Lubricant MB50-001 (DuPont; silicone masterbatch) 1 kg

[0024] The preparation method of the high thermal conductivity, chemical resistance and flame retardant polycarbonate composite material is the same as that in Example 1.

[0025] Performance characteristics:

[0026] Comparative Example 2: The raw materials for preparing high thermal conductivity, chemical resistance and flame retardant polycarbonate composite materials include: Polycarbonate (Wanhua; Clarnate® A1225) 65 kg; Spherical boron nitride (3M Company; particle size 1 μm) 30 kg; Flame retardant FR-2025 (3M Company; halogen-free flame retardant) 0.1 kg; Flame retardant F-535 (Arichem; sulfonate flame retardant) 0.5 kg; PTFE micropowder (3M Company; polytetrafluoroethylene micropowder) 2 kg; Silane coupling agent KH-550 (Dow Corning; γ-aminopropyltriethoxysilane) 0.3 kg; Toughening agent S-2030 (Mitsubishi Corporation; silicone acrylic rubber impact modifier) ​​2.5 kg; Toughening agent AX-8900 (Arkema; ​​ethylene acrylate glycidyl methacrylate) 1 kg; Antioxidant 1010 (BASF; pentaerythritol ester) 0.5 kg; Antioxidant 168 (BASF; phosphite antioxidant) 0.1 kg; Lubricant PETS P861 (formerly Corning; pentaerythritol stearate) 0.1 kg; Lubricant MB50-001 (DuPont; silicone masterbatch) 0.5 kg.

[0027] The preparation method of the high thermal conductivity, chemical resistance and flame retardant polycarbonate composite material is the same as that in Example 1.

[0028] Performance characteristics:

[0029] Comparison results of Example 1, Comparative Example 1 and Comparative Example 2: Example 1 is significantly better than Comparative Example 1 and Comparative Example 2.

[0030] Disadvantages of Comparative Example 1 compared to Example 1: The thermal conductivity is severely degraded (core functionality is lost). The heat deformation temperature decreases, increasing the risk of deformation in high-temperature environments.

[0031] Comparative Example 2 has disadvantages compared to Example 1: The high amount of boron nitride used results in a significant increase in economic costs, reduced material fluidity, and increased processing difficulty. Notched impact strength is severely reduced, long-term thermal-oxidative stability is insufficient, increasing the risk of embrittlement, and mechanical properties are mediocre.

[0032] Example 1 solves the traditional pain points of "brittleness, stickiness, and flammability" of highly filled PC systems through the four-dimensional innovation of "thermal network design-interface engineering-toughening synergy-processing lubrication". It has significant technical advantages in the field of electronic heat dissipation. Its performance parameters are close to the level of PEEK thermally conductive modified materials, and the economic cost is only 1 / 5 of the latter, which has high commercial value.

[0033] The above merely describes the embodiments of the present invention, and while the description is relatively specific and detailed, it should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A high thermal conductivity, chemical resistance and flame retardant polycarbonate composite material, characterized in that: The raw materials for preparing the composite include: 66-67 parts by weight of polycarbonate, 20-20.5 parts by weight of boron nitride, 3-3.05 parts by weight of PTFE micropowder, 0.5-0.55 parts by weight of silane coupling agent KH-550, 5-5.1 parts by weight of toughening agent S-2030, 2-2.05 parts by weight of toughening agent AX-8900, 0.2-0.25 parts by weight of lubricant PETS P861, and 0.7-0.75 parts by weight of lubricant MB50-001.

2. The high thermal conductivity, chemical resistance and flame retardant polycarbonate composite material according to claim 1, characterized in that: The raw materials for its preparation further include: 0.1-0.15 parts by weight of flame retardant FR-2025 and 0.5-0.55 parts by weight of flame retardant F-535.

3. The high thermal conductivity, chemical resistance and flame retardant polycarbonate composite material according to claim 1, characterized in that: The raw materials for its preparation further include: 0.7-0.75 parts by weight of antioxidant 1010 and 0.3-0.35 parts by weight of antioxidant 168.

4. The high thermal conductivity, chemical resistance and flame retardant polycarbonate composite material according to claim 2 or 3, characterized in that: The raw materials for its preparation include: 66 parts by weight of polycarbonate, 20 parts by weight of boron nitride, 0.1 parts by weight of flame retardant FR-2025, 0.5 parts by weight of flame retardant F-535, 3 parts by weight of PTFE micropowder, 0.5 parts by weight of silane coupling agent KH-550, 5 parts by weight of toughening agent S-2030, 2 parts by weight of toughening agent AX-8900, 0.7 parts by weight of antioxidant 1010, 0.3 parts by weight of antioxidant 168, 0.2 parts by weight of lubricant PETSP861, and 0.7 parts by weight of lubricant MB50-001.

5. The high thermal conductivity, chemical resistance and flame retardant polycarbonate composite material according to any one of claims 1 to 4, characterized in that: The boron nitride is spherical boron nitride with a particle size of 1-2 μm.

6. A method for preparing the high thermal conductivity, chemical resistance and flame retardant polycarbonate composite material according to any one of claims 1 to 5, characterized in that: include: High temperature mixing step, water bath cooling step and pelletizing step.

7. The preparation method according to claim 6, characterized in that In the high temperature mixing step, the high temperature is 280-285°C.

8. The preparation method according to claim 6, characterized in that During the high temperature mixing step, vacuum devolatilization is performed The preparation method according to claim 6, characterized in that During the water bath cooling step, the water bath temperature was 20-30°C.

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