Low-emission heat-conducting reinforced PET (polyethylene terephthalate) material and preparation method thereof

Abstract

The invention provides a low-emission heat-conducting reinforced PET material and a preparation method thereof, and belongs to the technical field of high polymer material modification. The material comprises the following components in parts by weight: 10-60 parts of PET; 5-50 parts of a reinforcing filler; 1-5 parts of zeolite; 1 to 5 parts of MOF; 5-20 parts of a heat-conducting filler; 0.1 to 2 parts of a toughening agent; 0.5 to 5 parts of a coupling agent; and 0.1 to 2 parts of an antioxidant. Wherein 1-2 parts of zeolite and 1-2 parts of MOF are compounded to form a low-emission adsorption system; the heat-conducting filler comprises a one-dimensional heat-conducting filler and a two-dimensional heat-conducting filler which are compounded to form a heat-conducting network. Through the synergistic effect of the low-emission adsorption system and the three-dimensional heat conduction network, the technical contradiction that the high heat conduction performance and the low emission performance of the material are difficult to consider at the same time is successfully solved. The obtained material simultaneously meets the requirements of high rigidity, high heat conductivity, low emission and the like, has excellent comprehensive performance, and is particularly suitable for workpieces with strict requirements on heat dissipation and cleanliness, such as automobile lamp brackets, camera shells and the like. The preparation process is simple and suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of polymer material modification technology, and in particular to a low-emission thermally conductive reinforced PET material and its preparation method. Background Technology

[0002] PET (polyethylene terephthalate) is a common linear aromatic polyester with excellent mechanical properties, chemical stability, and processability. With the development of new energy vehicles, the increasing number of cameras on vehicles, and the development and use of driver assistance systems, the requirements for materials are not only high in terms of mechanical properties, but also in terms of low heat emission and low fogging. At the same time, the increasing number of automotive lights and ambient lights generates a large amount of heat during operation. Surrounding components such as brackets and decorative rings need to dissipate this heat to ensure safe operation, placing higher demands on the thermal conductivity of materials. Current technologies struggle to achieve a balance between high thermal conductivity and low heat emission while maintaining the good mechanical properties of the PET matrix.

[0003] Therefore, there is an urgent need in this field to develop a PET composite material that can simultaneously meet the comprehensive performance requirements of high rigidity, high thermal conductivity, and low energy dissipation. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a low-emission, high-thermal-conductivity glass fiber reinforced PET composite material. This material not only possesses excellent mechanical strength and heat resistance, but more importantly, it can synergistically achieve superior performance in terms of low emission (low fogging) and high thermal conductivity, thus meeting the stringent material requirements of the modern automotive industry, especially for high-end headlights, camera mounts, and components near the windshield.

[0005] To achieve the above objectives, the present invention provides a low-emission thermally conductive reinforced PET material, comprising, by weight: PET: 10-60 parts; Reinforcing filler: 5-50 parts; Zeolite: 1-5 parts; MOF: 1-5 parts; Thermally conductive filler: 5-20 parts; Toughening agent: 0.1-2 parts; Coupling agent: 0.5-5 parts; Antioxidant: 0.1-2 parts; Among them, 1-5 parts of zeolite and 1-5 parts of MOF are combined to form a low-emission adsorption system; The thermally conductive filler includes one-dimensional thermally conductive filler and two-dimensional thermally conductive filler, which together form a thermally conductive network.

[0006] Furthermore, the reinforcing filler is alkali-free glass fiber with a diameter of 10-30 μm.

[0007] Furthermore, the zeolite is any one or a combination of at least two of the following: natural zeolite and artificial zeolite.

[0008] Furthermore, the MOF is any one or a combination of at least two of Zr-based UiO-66 and Al-based MIL-53.

[0009] Furthermore, the thermally conductive filler includes one-dimensional thermally conductive filler and two-dimensional thermally conductive filler; The mass ratio range of one-dimensional and two-dimensional thermally conductive fillers is 3:1 to 1:3.

[0010] The one-dimensional thermally conductive filler is a carbon nanotube; The two-dimensional thermally conductive filler is expanded graphite, graphene sheets, boron nitride, or aluminum nitride.

[0011] Furthermore, the toughening agent includes any one or a combination of at least two of the following: methyl methacrylate-butadiene-styrene copolymer, maleic anhydride-grafted ethylene-octene copolymer elastomer, ethylene-butyl acrylate-glycidyl methacrylate copolymer, ethylene-methyl acrylate-glycidyl methacrylate copolymer, or methyl methacrylate-styrene-silicone copolymer.

[0012] Furthermore, the coupling agent includes any one or a combination of at least two of silane coupling agents, titanate coupling agents, or aluminate coupling agents.

[0013] Furthermore, the silane coupling agent includes any one or a combination of at least two of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, or γ-glycidoxypropyltriethoxysilane; the titanate coupling agent includes isopropyl dioleoyloxy (dioctylphosphoyloxy) titanate.

[0014] Furthermore, the antioxidant includes any one or a combination of at least two of the following: hindered phenolic antioxidants, hindered amine antioxidants, phosphite antioxidants, or thioester antioxidants.

[0015] This invention also proposes a method for preparing a low-emission, thermally conductive reinforced PET material, comprising the following steps: S1: Weigh the raw material components according to the weight ratio of claim 1, and mix PET, zeolite, MOF, thermally conductive filler, toughening agent, coupling agent and antioxidant evenly in a high-speed mixer; S2: Feed the mixture into a twin-screw extruder and melt-mix it at 240-280℃; S3: During melt mixing, the reinforcing filler is added using a side-feeding method at a speed of 200-400 r / min. S4: The melt obtained after melt mixing is melt extruded, water-cooled, and pelletized to obtain the composite material; wherein the length-to-diameter ratio of the screw of the twin-screw extruder is in the range of 30-50, and the screw speed of the extruder is in the range of 400-700 r / min.

[0016] Compared with the prior art, the advantages of the present invention are: 1. This invention employs a low-emission adsorption system composed of zeolite and MOF, utilizing the complementarity of their porous structure and surface chemistry to efficiently and synergistically adsorb and lock small-molecule volatiles generated during the processing and use of PET, controlling the emission of small molecules and significantly reducing the fogging value at the source, thus giving the material low emission properties. Simultaneously, the invention combines a three-dimensional thermally conductive network constructed from one-dimensional and two-dimensional thermally conductive fillers through surface-to-surface and point-to-point composite processes, endowing the material with excellent thermal conductivity. While achieving efficient thermal conductivity, the introduction of the adsorbent does not significantly disrupt the thermal conductivity pathway, successfully resolving the traditional contradiction between "high thermal conductivity" and "low emission," achieving an excellent balance between mechanical properties, thermal conductivity, and low emission performance, making it suitable for applications such as automotive lights and ambient lighting.

[0017] 2. The material preparation method of this invention has a simple process, and the equipment used is all common equipment in the polymer modification industry. The process parameters are easy to control, which is very suitable for large-scale industrial production and has extremely high market promotion value. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be further described below.

[0019] This invention presents five embodiments of low-emission thermally conductive reinforced PET materials and three comparative examples.

[0020] The intrinsic viscosity of the PET material used in the following examples and comparative examples is 0.8 dl / g. The reinforcing filler used in the following examples and comparative examples is alkali-free glass fiber with a diameter of 13 μm.

[0021] The MOF used in the following examples and comparative examples is Zr-based UiO-66, which is commercially available.

[0022] The one-dimensional thermally conductive filler used in the following examples and comparative examples is carbon nanotube, and the two-dimensional thermally conductive filler is boron nitride sheet.

[0023] The toughening agents used in the following examples and comparative examples include any one or a combination of at least two of the following: methyl methacrylate-butadiene-styrene copolymer, maleic anhydride-grafted ethylene-octene copolymer elastomer, ethylene-butyl acrylate-glycidyl methacrylate copolymer, ethylene-methyl acrylate-glycidyl methacrylate copolymer, or methyl methacrylate-styrene-silicone copolymer.

[0024] The coupling agents used in the following examples and comparative examples are silane coupling agents, including any one or a combination of at least two of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, or γ-glycidoxypropyltriethoxysilane.

[0025] The antioxidants used in the following examples and comparative examples include any one or a combination of at least two of hindered phenolic antioxidants, hindered amine antioxidants, phosphite antioxidants, or thioester antioxidants.

[0026] Comparative Example 1 (excluding MOF, one-dimensional thermally conductive filler and two-dimensional thermally conductive filler) A PET modified material, by weight, comprises the following components: PET: 64 parts; reinforcing filler (glass fiber): 30 parts; zeolite: 3 parts; toughening agent: 0.7 parts; coupling agent: 2 parts; antioxidant: 0.3 parts.

[0027] Comparative Example 2 (excluding zeolite and two-dimensional thermally conductive filler) A PET modified material, by weight, comprises the following components: PET: 49 parts; Reinforcing filler (glass fiber): 30 parts; MOF: 3 parts; One-dimensional thermally conductive filler: 15 parts; Toughening agent: 0.7 parts; Coupling agent: 2 parts; Antioxidant: 0.3 parts.

[0028] Comparative Example 3 (excluding MOF and one-dimensional thermally conductive filler) A PET modified material, by weight, comprises the following components: PET: 49 parts; Reinforcing filler (glass fiber): 30 parts; Zeolite: 3 parts; Two-dimensional thermally conductive filler: 15 parts; Toughening agent: 0.7 parts; Coupling agent: 2 parts; Antioxidant: 0.3 parts.

[0029] Example 1 A low-emission, thermally conductive reinforced PET material, comprising, by weight: PET: 49 parts; Reinforcing filler (glass fiber): 30 parts; Zeolite: 1.5 parts; MOF: 1.5 parts; One-dimensional thermally conductive filler: 8 parts; Two-dimensional thermally conductive filler: 7 parts; Toughening agent: 0.7 parts; Coupling agent: 2 parts; Antioxidant: 0.3 parts.

[0030] Example 2 A low-emission, thermally conductive reinforced PET material, comprising, by weight: PET: 48 parts; Reinforcing filler (glass fiber): 30 parts; Zeolite: 2 parts; MOF: 2 parts; One-dimensional thermally conductive filler: 10 parts; Two-dimensional thermally conductive filler: 5 parts; Toughening agent: 0.7 parts; Coupling agent: 2 parts; Antioxidant: 0.3 parts.

[0031] Example 3 A low-emission, thermally conductive reinforced PET material, comprising, by weight: PET: 46 parts; Reinforcing filler (glass fiber): 30 parts; Zeolite: 3 parts; MOF: 3 parts; One-dimensional thermally conductive filler: 5 parts; Two-dimensional thermally conductive filler: 10 parts; Toughening agent: 0.7 parts; Coupling agent: 2 parts; Antioxidant: 0.3 parts.

[0032] Example 4 A low-emission, thermally conductive reinforced PET material, comprising, by weight: PET: 41 parts; Reinforcing filler (glass fiber): 30 parts; Zeolite: 3 parts; MOF: 3 parts; One-dimensional thermally conductive filler: 10 parts; Two-dimensional thermally conductive filler: 10 parts; Toughening agent: 0.7 parts; Coupling agent: 2 parts; Antioxidant: 0.3 parts.

[0033] Example 5 A low-emission, thermally conductive reinforced PET material, comprising, by weight: PET: 51 parts; Reinforcing filler (glass fiber): 30 parts; Zeolite: 3 parts; MOF: 3 parts; One-dimensional thermally conductive filler: 5 parts; Two-dimensional thermally conductive filler: 5 parts; Toughening agent: 0.7 parts; Coupling agent: 2 parts; Antioxidant: 0.3 parts.

[0034] The preparation methods for the PET modified materials in Examples 1-5 and Comparative Examples 1-3 are the same, as detailed below: S1: Weigh the raw material components according to the weight ratio of each embodiment or comparative example, and mix PET, zeolite, MOF, thermally conductive filler, toughening agent, coupling agent and antioxidant evenly in a high-speed mixer; S2: The mixture is fed into a twin-screw extruder and melt-mixed at 250, 255, 265, 265, 265, 260, 255, 250, 250°C. S3: During melt mixing, the reinforcing filler is added by side feeding at a speed of 300 r / min; S4: The melt obtained after melt mixing is melt extruded, water-cooled, and pelletized to obtain the composite material; wherein the twin-screw extruder has a screw length-to-diameter ratio of 36 and an extruder screw speed of 550 r / min.

[0035] The PET materials obtained in Comparative Examples 1-3 and Examples 1-5 were subjected to tensile property tests, flexural property tests, impact property tests, heat resistance tests, fogging tests, and thermal conductivity tests, respectively.

[0036] The testing methods and standards used are as follows: (1) Tensile properties: The tensile strength (MPa) of the material is tested according to the method in ISO 527.

[0037] (2) Bending properties: The bending modulus (MPa) and bending strength (MPa) of the material are tested according to the method in ISO 178.

[0038] (3) Impact performance: The notched impact strength of the simply supported beam of the material was tested according to the method in ISO 179, and the ambient temperature was 23℃.

[0039] (4) Heat resistance: The heat distortion temperature of the material shall be tested in accordance with the method in ISO 75.

[0040] (5) Atomization: Tested according to the optical method in SAE J1756.

[0041] (6) Thermal conductivity: Tested according to ASTM E1461.

[0042] The final test results of the reinforced PET materials of Comparative Examples 1-3 and Examples 1-5 are shown in Table 1 below: Table 1

[0043] The test results in Table 1 show that: Comparative Example 1 (zeolite only, no thermally conductive filler): mediocre heat dissipation performance and extremely poor thermal conductivity.

[0044] Comparative Example 2 (MOF only, one-dimensional filler only): Limited improvement in heat dissipation, imperfect heat conduction network, and low thermal conductivity.

[0045] Comparative Example 3 (zeolite only, two-dimensional filler only): its emission performance is better than that of Comparative Example 1, but its thermal conductivity and atomization performance are significantly lower than those of the embodiments of the present invention.

[0046] As can be seen, Comparative Examples 1-3 respectively demonstrate the limitations of using zeolite, MOF or single-dimensional thermally conductive filler, and their overall performance (especially the balance between atomization value and thermal conductivity) is not ideal.

[0047] Examples 1-5 of this invention (zeolite / MOF composite, multidimensional thermally conductive filler) all exhibit excellent comprehensive performance, especially in terms of simultaneous and significant improvement in atomization retention rate and thermal conductivity. All examples meet the requirements of atomization test gloss retention rate ≥80%, thermal conductivity ≥0.8 W / m·K, and flexural modulus ≥10,500 MPa. This fully demonstrates that under the synergistic effect of the zeolite / MOF composite adsorption system and the multidimensional thermally conductive network construction system, even with changes in PET content, type and proportion of thermally conductive filler, the material can still stably achieve an excellent balance between low emission and high thermal conductivity, and the mechanical properties remain at a high level.

[0048] The above are merely preferred embodiments of the present invention and do not constitute any limitation on the present invention. Any equivalent substitutions or modifications made by those skilled in the art to the technical solutions and content disclosed in the present invention without departing from the scope of the present invention shall be deemed to have remained within the protection scope of the present invention.

Claims

1. A low-emission thermally enhanced PET material, characterized in that, By weight parts, including: PET: 10-60 parts; reinforcing filler: 5-50 parts; Zeolite: 1-5 parts; MOF: 1-5 parts; thermal conductive filler: 5-20 parts; toughening agent: 0.1-2 parts; coupling agent: 0.5-5 parts; antioxidant: 0.1-2 parts; Among them, 1-5 parts of zeolite and 1-5 parts of MOF are compounded to form a low-emission adsorption system; The thermal conductive filler includes one-dimensional thermal conductive filler and two-dimensional thermal conductive filler, and is compounded to form a thermal conductive network.

2. The low-emissivity, thermally enhanced PET material of claim 1, wherein, The reinforcing filler is alkali-free glass fiber with a diameter of 10-30 um.

3. The low-emissivity, thermally enhanced PET material of claim 1, wherein, The zeolite is any one or a combination of at least two of natural zeolite and artificial zeolite.

4. The low-emissivity, thermally enhanced PET material of claim 1, wherein, The MOF is any one or a combination of at least two of Zr-based UiO-66 and Al-based MIL-53.

5. The low-emissivity, thermally enhanced PET material of claim 1, wherein, The thermal conductive filler includes one-dimensional thermal conductive filler and two-dimensional thermal conductive filler; The one-dimensional thermal conductive filler is carbon nanotube; The two-dimensional thermal conductive filler is expanded graphite, graphene sheet, boron nitride or aluminum nitride; The mass ratio of the one-dimensional thermal conductive filler and the two-dimensional thermal conductive filler ranges from 3:1 to 1:

3.

6. The low-emissivity, thermally enhanced PET material of claim 1, wherein, The toughening agent includes any one or a combination of at least two of methyl methacrylate-butadiene-styrene copolymer, maleic anhydride grafted ethylene-octene copolymer elastomer, ethylene-butyl acrylate-glycidyl methacrylate copolymer, ethylene-methyl methacrylate-glycidyl methacrylate copolymer or methyl methacrylate-styrene-silicone copolymer.

7. The low-emissivity, thermally enhanced PET material of claim 1, wherein, The coupling agent includes any one or a combination of at least two of silane coupling agent, titanate coupling agent or aluminate coupling agent.

8. The low-emissivity, thermally enhanced PET material of claim 7, wherein, The silane coupling agent includes any one or a combination of at least two of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidyl ether propyltrimethoxysilane or γ-glycidyl ether propyltriethoxysilane.

9. The low-emissivity, thermally enhanced PET material of claim 1, wherein, The antioxidant includes any one or a combination of at least two of hindered phenolic antioxidant, hindered amine antioxidant, phosphite antioxidant or sulfur ester antioxidant.

10. A method of preparing a low-emission thermally-conductive enhanced PET material, characterized in that, The method comprises the following steps: S1: weigh the raw material components according to the weight ratio of claim 1, and mix the PET, zeolite, MOF, thermal conductive filler, toughening agent, coupling agent and antioxidant uniformly in a high-speed mixer; S2: put the mixed material into a double-screw extruder and melt mix at 240-280℃; S3: during melt mixing, the reinforcing filler is added by side feeding at a speed of 200-400 r / min S4: melt extrude, water cool and pelletize the melt obtained after melt mixing to obtain the composite material; wherein the length-diameter ratio of the screw of the double-screw extruder ranges from 30 to 50, and the screw speed of the extruder ranges from 400 to 700 r / min.

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