Cycloolefin copolymer-based composite material for wafer transfer box as well as preparation method and application of cycloolefin copolymer-based composite material

Abstract

The invention discloses a cycloolefin copolymer-based composite material for a wafer transfer box as well as a preparation method and application of the cycloolefin copolymer-based composite material. The cycloolefin copolymer-based composite material comprises the following raw materials in percentage by weight: 70-89% of a cycloolefin copolymer, 3-20% of a toughening agent, 5-15% of a dynamic crosslinking compatilizer, 2-8% of carbon nanotubes, 0.1-0.4% of a main antioxidant, 0.05-0.3% of an auxiliary antioxidant and 0.1-1% of a surfactant. The dynamic connection compatibilizer is a polymer formed by connecting anhydride functionalized COC and epoxy functionalized SEBS through an epoxy-anhydride reaction, and the link bond has dynamic characteristics and can retain the thermoplasticity of the material. A dispersion method of solution-grinding-high-speed ultrasonic mixing is used for improving the dispersion degree and interface bonding of all components in a matrix, the composite material has conductive stability, high strength and toughness, low ion content and low gas release property, the surface of an injection molded part is free of pocking marks and melt flow marks, and the composite material can be applied to preparation of a front-open type wafer transmission box.

Description

Technical Field

[0001] This invention relates to the field of polymer composite material preparation, specifically to a cyclic olefin copolymer-based (COC) composite material for wafer transfer boxes and its preparation method. Background Technology

[0002] As a core component in semiconductor manufacturing that carries and protects wafers, wafer transfer boxes have stringent requirements for the comprehensive performance of the materials used: they must have excellent conductivity to avoid electrostatic damage to the wafer, high strength and toughness to ensure structural stability, low ion content and low gas release to prevent contamination of the environment in which the wafer is located, and the surface after injection molding must be free of pits and melt flow marks to meet the appearance and usage requirements of precision components.

[0003] Cyclo-Olefin copolymers (COCs) are preferred matrix resins for wafer transfer boxes due to their low ion content and low gas release properties. However, since COCs mainly refer to copolymers of norbornene and other olefins, the presence of numerous norbornene segments in the macromolecular chain leads to significant steric hindrance, making rotation within the molecular chain difficult and resulting in poor material toughness. Toughening agents are needed to enhance the toughness. CN118591873A discloses a polymer blend for microenvironment applications, using polyolefin elastomers and styrene-based elastomers to toughen COCs. However, due to the polarity differences between the different molecular chains, simple physical blending results in poor compatibility, easily leading to phase separation and fluctuations in the material's mechanical properties, and melt flow marks during injection molding. CN114479333A discloses a low-creep, high-toughness COC composite material and its preparation method, prepared through melt grafting. This material exhibits good compatibility with COCs, effectively toughening them while improving creep resistance. However, during the preparation of compatibilizers using this method, due to the randomness of the free radical initiator, in addition to the grafted products of COC-g-POE, a large number of POE self-crosslinking and COC self-crosslinking products are introduced, which loses the characteristic of thermoplastic materials being reprocessable. The generation of a large number of crosslinked structures is also not conducive to the dispersion of toughening agents and conductive fillers and other components in the matrix resin.

[0004] The resistivity of cyclic olefin copolymers is 10 17The above-mentioned materials require conductivity modification before they can be used in wafer cell products. Carbon nanotubes, with their excellent mechanical, electrical, and thermal properties, have broad application prospects in composite materials. However, in practical applications, carbon nanotubes are prone to agglomeration and uneven dispersion, leading to a significant decrease in the mechanical properties of composite materials containing carbon nanotubes. Poor dispersion of carbon nanotubes also results in numerous pits on the surface of the parts. The masterbatch method is a common means of optimizing filler dispersion. CN119912751A discloses a polypropylene material based on nanofiller toughening technology and its preparation process, utilizing a masterbatch method for secondary separation... Dispersed nano-silica involves first preparing a nano-silica masterbatch, then mixing it with other components. This improves the uniformity of nano-silica dispersion in composite materials and ensures the uniform dispersion of nanofillers in a polypropylene matrix. However, the masterbatch method requires multiple extrusion processes, which are cumbersome and significantly increase time and energy consumption. Furthermore, the extrusion process inevitably leads to thermal degradation of the resin matrix and breakage of carbon nanotubes, affecting the material's mechanical properties and electrical conductivity stability. Compared to other nanomaterials, the tubular structure of carbon nanotubes makes them more prone to entanglement, and carbon nanotube agglomeration can still be observed in composite materials prepared solely by the masterbatch method. Current technologies cannot simultaneously solve the three core problems of "compatibility, dispersibility, and surface quality" among the resin matrix, toughening agent, and carbon nanotubes. Summary of the Invention

[0005] This invention provides a cyclic olefin copolymer for wafer transfer boxes and its preparation method. Using dynamic covalent bonds as a bridge, it specifically connects the COC and SEBS molecular chains, solving the two-phase compatibility problem while ensuring the thermoplastic properties of the material due to the use of dynamic bonds. Surface treatment of carbon nanotubes reduces their tendency to agglomerate. A multi-stage dispersion process involving "solution-grinding-ultrasonic assistance" addresses the agglomeration problem of carbon nanotubes, ultimately obtaining a composite material with uniform conductivity, high strength and toughness, low ion content, low gas release, and no pitting or flow marks on the injection-molded surface.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A cyclic olefin copolymer-based composite material for wafer transport boxes comprises the following components:

[0008] 70-89 wt% cyclic olefin copolymers; preferably 75-85 wt%;

[0009] Toughening agent 3-20 wt%; preferably 5-15 wt%;

[0010] Dynamic linker compatibilizer 5-15 wt%; preferably 6-10 wt%;

[0011] Carbon nanotubes 2-8 wt%; preferably 3-6 wt%;

[0012] The main antioxidant is 0.1-0.4 wt%; preferably 0.2-0.3 wt%.

[0013] The auxiliary antioxidant is 0.05-0.3 wt%; preferably 0.1-0.2 wt%.

[0014] Surfactant 0.1-1 wt%; preferably 0.3-0.7 wt%.

[0015] The cyclic olefin copolymer described in this invention is designated as Topas 6013.

[0016] The toughening agent described in this invention includes a styrene-based thermoplastic elastomer, specifically a hydrogenated styrene / butadiene block copolymer (SEBS).

[0017] Preferably, the styrene content of the styrene-based thermoplastic elastomer is 20-40 wt%, more preferably 27-33 wt%.

[0018] Preferably, in order to achieve a better toughening effect, the glass transition temperature of the polybutadiene soft segment in the SEBS is less than -60°C; to ensure that the toughening agent is uniformly dispersed in the matrix, the selected toughening agent has a weight-average molecular weight of 15-25w, which matches the viscosity of the cyclic olefin copolymer base material.

[0019] The preparation method of the dynamic link compatibilizer of the present invention includes the following steps:

[0020] (1) Preparation of COC-g-MAH: Cycloolefin copolymer, maleic anhydride and free radical initiator are mixed and reacted in a twin-screw extruder;

[0021] (2) Preparation of SEBS-g-GMA: SEBS, glycidyl methacrylate and free radical initiator are mixed and reacted in a twin-screw extruder;

[0022] (3) Preparation of dynamic bonding compatibilizer: COC-g-MAH, SEBS-g-GMA and transesterification catalyst are mixed and reacted in a twin-screw extruder.

[0023] In step (1) of this invention, the cyclic olefin copolymer is Topas 6013.

[0024] In step (1) of the present invention, the weight ratio of the cyclic olefin copolymer to maleic anhydride is 1:0.04-0.08.

[0025] In step (1) of this invention, the amount of free radical initiator is 0.2-0.5 wt% of the weight of the cyclic olefin copolymer.

[0026] In step (1) of this invention, maleic anhydride is grafted onto the COC molecular chain by free radical initiation.

[0027] In step (1) of the present invention, the temperature of the feeding section of the twin-screw extruder is 200-230°C, the temperature of the melting section is 240-270°C, the temperature of the plasticizing section is 240-270°C, and the temperature of the extrusion section is 240-270°C.

[0028] Preferably, step (1) of the present invention further includes a granulation step after extrusion.

[0029] In step (2) of this invention, SEBS is Kronen's G1651.

[0030] In step (2) of this invention, the weight ratio of SEBS to glycidyl methacrylate is 1:0.04-0.08.

[0031] In step (2) of this invention, the amount of free radical initiator is 0.2-0.5 wt% of the weight of SEBS.

[0032] In step (2) of the present invention, glycidyl methacrylate is grafted onto the SEBS molecular chain by free radical initiation.

[0033] In step (2) of the present invention, the temperature of the feeding section of the twin-screw extruder is 160-200°C, the temperature of the melting section is 180-210°C, the temperature of the plasticizing section is 180-210°C, and the temperature of the extrusion section is 180-210°C.

[0034] Preferably, step (2) of the present invention further includes a granulation step after extrusion.

[0035] In step (3) of the present invention, the weight ratio of COC-g-MAH to SEBS-g-GMA is 1:1.5 to 2.

[0036] In step (3) of this invention, the amount of transesterification catalyst used is 0.05-0.1 wt% of the sum of the weights of COC-g-MAH and SEBS-g-GMA.

[0037] In step (3) of the present invention, under the catalysis of the transesterification catalyst, the epoxy group reacts with the acid anhydride group to specifically link the COC and SEBS molecular chains, and the covalent bond has dynamic characteristics. The dynamic link compatibilizer still has the characteristics of thermoplastic material.

[0038] In step (3) of the present invention, the temperature of the feeding section of the twin-screw extruder is 200-230°C, the temperature of the melting section is 240-270°C, the temperature of the plasticizing section is 240-270°C, and the temperature of the extrusion section is 240-270°C.

[0039] Preferably, step (3) of the present invention further includes a granulation step after extrusion.

[0040] The free radical initiator described in this invention includes one or more of peroxide initiators and azo compound initiators.

[0041] The transesterification catalyst of the present invention includes zinc methacrylate and / or zinc acetylacetone.

[0042] The preparation method of the dynamic bonding compatibilizer of the present invention adopts a reactive extrusion process, in which COC and maleic anhydride are reacted under the action of a free radical initiator to obtain anhydride-functionalized COC; SEBS and glycidyl methacrylate are reacted under the action of an initiator to introduce epoxy groups into the butadiene segments of SEBS to obtain epoxy-functionalized SEBS; the two functionalized resins are mixed and then an ester exchange catalyst is added to catalyze the reaction between epoxy groups and anhydride groups to form a "COC-dynamic covalent bond-SEBS" bridging structure. This dynamic covalent bond exhibits dynamic exchangeability under zinc ion catalysis. The bond breaks upon heating, which facilitates melt processing, and the bond recombines upon cooling to restore the interfacial bonding strength, thus solving phase separation while retaining the thermoplasticity of the material.

[0043] Carbon nanotubes with an aspect ratio of less than 1000 are preferred to reduce carbon nanotube aggregation. The wafer transfer box industry has extremely stringent requirements for material cleanliness; therefore, the preferred carbon nanotubes have iron and cobalt ion residues of less than 800 ppm. More preferably, the carbon nanotubes are surface modified to reduce their tendency to aggregate.

[0044] Preferably, a method for surface modification of carbon nanotubes includes the following steps: dispersing CNTs in an acidic solution for oxidation treatment, and adding a silane coupling agent for reaction.

[0045] In the preparation method of carbon nanotubes described in this invention, the acidic solution is concentrated sulfuric acid or a hydrochloric acid-nitric acid mixture. Active groups such as hydroxyl and / or carboxyl groups are introduced through oxidation treatment.

[0046] In the preparation method of carbon nanotubes described in this invention, the active end of the silane coupling agent reacts with the hydroxyl and / or carboxyl groups on the CNT surface to graft organic segments with excellent compatibility with the COC matrix onto the CNT surface, thereby reducing the tendency of CNTs to aggregate in the matrix resin.

[0047] The processing method of solution-grinding-ultrasonic assisted dispersion is adopted. Solution dispersion enables the additives to be uniformly attached to the surface of COC particles, enhancing the surface activity of COC. Grinding dispersion enables the carbon nanotubes to be tightly bonded to COC, making the electrical properties of the product more stable. After high-speed mixing in a high-speed mixer, it is used in conjunction with an ultrasonic dispersion device during the extrusion process. Under the synergistic effect of ultrasonic vibration and screw shearing, the dispersion of carbon nanotubes is further refined.

[0048] By using a special solution-grinding-ultrasonic dispersion process to improve the conductive filler and the composite material, it can be used to prepare the shell structure of a wafer transport box, which is configured to hold and transport semiconductor wafers.

[0049] The preparation method of the cyclic olefin copolymer-based composite material for wafer transport boxes according to the present invention includes the following steps: according to the proportion,

[0050] S1. Dissolve the surfactant, primary antioxidant, and secondary antioxidant in acetone, disperse them uniformly on the surface of the cyclic olefin copolymer, and remove the solvent by heating;

[0051] S2. Mix and grind the product from S1 with carbon nanotubes to obtain powder;

[0052] S3. Mix the S1 product, S2 product, toughening agent, and dynamic bonding compatibilizer evenly;

[0053] S4. The product from S3 is extruded and granulated using a twin-screw extruder.

[0054] In S1 of this invention, the surface activity of the matrix resin is improved, and the additives are uniformly adhered to the surface of the resin particles.

[0055] Preferably, the acetone dissolving aid is dissolved under ultrasound for 3-5 minutes to ensure complete dissolution;

[0056] Preferably, the COC resin particles are dried in a vacuum oven at a temperature of 60°C;

[0057] In the present invention, the weight ratio of carbon nanotubes to the product of S1 in S2 is 1:0.8-1.2.

[0058] In S2 of this invention, the grinding is performed using a horizontal grinding machine.

[0059] In S2 of this invention, the grinding speed is 1500-200 rpm and the grinding time is 20-30 min.

[0060] As a preferred embodiment, in S3 of the present invention, a high-speed mixer is used for mixing; preferably, the high-speed mixer speed is 3000-3500 rpm; the mixing temperature is 60-70℃; and the mixing time is 5-8 min.

[0061] As a preferred embodiment, in step S4, the ultrasonic dispersion device located at the die head of the twin-screw extruder is activated.

[0062] Preferably, the ultrasonic power of the ultrasonic dispersion device is 300-500W, and the ultrasonic frequency is set to 20-30kHz.

[0063] As a preferred embodiment, the temperature of the feeding section of the twin-screw extruder is 200–230°C.

[0064] As a preferred embodiment, the temperature of the melting section of the twin-screw extruder is 240–270°C.

[0065] As a preferred embodiment, the temperature of the plasticizing section of the twin-screw extruder is 240–270°C.

[0066] As a preferred embodiment, the temperature of the extrusion section of the twin-screw extruder is 240–270°C.

[0067] As a preferred embodiment, the extrusion process further includes a granulation step.

[0068] The beneficial effects of this invention include:

[0069] (1) High efficiency of modified additives: Dynamic crosslinking compatibilizers achieve stable compatibilization by specifically covalently linking COC and SEBS molecular chains. Compared with traditional methods, the interfacial bonding strength of materials is improved and the impact strength is increased by 60%-90%.

[0070] (2) Both conductivity uniformity and surface quality are taken into account: The multi-stage dispersion process of "chemical modification of carbon nanotubes + solution-grinding dispersion-ultrasonic assisted extrusion" combined with dynamic bonding compatibilizer to optimize the matrix interface improves the uniformity of CNT dispersion by more than 40%, the volume resistivity fluctuation is less than 10%, and there are no pits on the surface of the injection molded parts; the exchangeable characteristics of dynamic bonds can also eliminate stress concentration during injection molding and avoid the generation of melt flow marks.

[0071] (3) Comprehensive performance meets semiconductor requirements: Using COC with low ion content and low gas release as the matrix, no additional ions are introduced into each component, the ion content of the final product is less than 1 ppm, and the gas release at 25℃ for 24 hours is less than 0.1 mg / cm³. 2 It also possesses high strength (tensile strength greater than 52MPa) and high toughness (impact strength greater than 7.5Kj / m). 2 It meets the requirements for use of wafer cassettes and can be used to prepare wafer transport carriers, including front-opening wafer transport cassettes and wafer baskets. Detailed Implementation

[0072] To facilitate understanding of the present invention, the following description, in conjunction with embodiments, will further illustrate the invention. It should be understood that the following embodiments are merely for a better understanding of the invention and do not imply that the invention is limited to these embodiments.

[0073] The materials and instruments used in this invention are as follows:

[0074] Twin-screw extruder: Nanjing Ruya, Model: Ruya 26 extruder.

[0075] Injection molding machine: Haitian Plastics Machinery, model MA2500Ⅲ / 1000.

[0076] Tabletop high-speed centrifuge: Titan, model YTGL001-15K

[0077] Cyclic olefin copolymer: Topas 6013, melt index 12 g / 10 min (260℃, 2.16 kg).

[0078] Carbon nanotubes: Tiannai Technology.

[0079] Toughening agent: Kraton, SEBS G1651.

[0080] Antioxidant: Ciba Specialty Chemicals, Switzerland, Antioxidant 1010.

[0081] Free radical initiator: bis(tert-butylperoxyisopropylbenzene) (BIPB), 99% purity, Akema.

[0082] Ester exchange catalyst: Zinc methacrylate, 99% purity, Akema.

[0083] Maleic anhydride: Adamas, 98% purity. Glycidyl methacrylate: Adamas, 98% purity.

[0084] Preparation Example 1

[0085] Dynamic linker compatibilizer is prepared through the following steps:

[0086] Preparation of S1.COC-g-MAH: COC-g-MAH (COC grafted with maleic anhydride)

[0087] Ingredients: 1kg COCTopas 6013, 60g maleic anhydride, 3.7g free radical initiator (diisopropylbenzene peroxide).

[0088] Mixing: The raw materials are added to a twin-screw extruder for free radical grafting. The temperature of the feeding section of the twin-screw extruder is 220℃, the temperature of the melting section is 240℃, the temperature of the plasticizing section is 250℃, and the temperature of the extrusion section is 250℃. The screw speed is 300 rpm. After pelleting, COC-g-MAH particles are obtained.

[0089] S2.SEBS-g-GMA (SEBS-grafted glycidyl methacrylate)

[0090] Ingredients: SEBSG1651 1kg, glycidyl methacrylate 60g, free radical initiator 3.7g.

[0091] Compounding: The raw materials are added to a twin-screw extruder for free radical grafting. The temperature of the twin-screw extruder is 170℃ in the feeding section, 190℃ in the melting section, 190℃ in the plasticizing section, and 190℃ in the extrusion section; the screw speed is 300 rpm. After pelleting, SEBS-g-GMA particles are obtained.

[0092] S3. Dynamically linked compatibilizer (COC-g-MAH / SEBS-g-GMA)

[0093] Ingredients: COC-g-MAH 500g: SEBS-g-GMA 900g (1:1.8 in this example). Transesterification catalyst (zinc methacrylate) 5.5g.

[0094] Mixing: The temperature of the feeding section of the twin-screw extruder is 220℃, the temperature of the melting section is 250℃, the temperature of the plasticizing section is 250℃, and the temperature of the extrusion section is 250℃; the screw speed is 300 rpm, and the dynamic bonding compatibilizer is obtained after pelleting.

[0095] Preparation Example 2

[0096] Surface chemical modification of carbon nanotubes

[0097] S1. Acid oxidation: Disperse 100g of CNT in a mixture of 180mL of 98% concentrated sulfuric acid and 60mL of 68% concentrated nitric acid (volume ratio 3:1), sonicate for 30min (room temperature), then sonicate at 50℃ for 6h. Centrifuge, wash with deionized water until pH≈7, and vacuum dry at 80℃ to constant weight.

[0098] S2. Silane Coupling: Oxidized CNTs and γ-aminopropyltriethoxysilane (APTES) 1 wt% were stirred at 80°C for 2 h in a mixed solvent of ethanol-water (95:5) to allow the active end of the silane to react with the hydroxyl / carboxyl groups on the surface of the CNTs to form organic segments that are affinity for the COC matrix.

[0099] Example 1

[0100] In this embodiment, a cyclic olefin copolymer-based composite material for wafer transfer boxes is prepared. By weight, the composite material includes 80 parts of cyclic olefin copolymer, 5 parts of surface-modified carbon nanotubes, 8.2 parts of toughening agent, 6 parts of dynamic bonding compatibilizer, 0.2 parts of antioxidant 1010, 0.1 parts of auxiliary antioxidant, and 0.5 parts of surfactant.

[0101] S1. Dissolve 2g of antioxidant 1010, 1g of co-antioxidant 168, and 5g of surfactant sodium dodecylbenzenesulfonate in 50ml of acetone solution. Add 700g of COC Topas 6013 particles and stir for 10min. Then dry at 60 degrees Celsius for later use.

[0102] S2. Take 50g of surface-modified carbon nanotubes and 100g of product S1 and grind them in a horizontal grinder for 25 minutes at a speed of 1500 rpm.

[0103] S3. Add the materials obtained in S1 and S2, along with 82g of toughening agent SEBS G1651 and 80g of dynamic bonding compatibilizer, to a high-speed mixer for high-speed mixing at 3200 rpm and 65°C for 5 minutes.

[0104] S4. The material is fed into the twin-screw extruder, and ultrasonic assisted dispersion is turned on with a power of 400W and a frequency of 25kHz. The temperature of the mixing and feeding section is 220℃, the temperature of the melting section is 240℃, the temperature of the plasticizing section is 250℃, the temperature of the extrusion section is 250℃, and the screw speed is 300rpm.

[0105] S5. Add the granulated material into the injection molding machine. Set the barrel temperature of the injection molding machine to 240-270℃, the mold temperature to 80℃, and the injection pressure to 100MPa.

[0106] Example 2

[0107] In this embodiment, a cyclic olefin copolymer-based composite material for wafer transfer boxes is prepared. By weight, the composite material includes 78 parts of cyclic olefin copolymer, 5 parts of surface-modified carbon nanotubes, 8.2 parts of toughening agent, 8 parts of dynamic bonding compatibilizer, 0.2 parts of antioxidant 1010, 0.1 parts of auxiliary antioxidant, and 0.5 parts of surfactant.

[0108] S1. Dissolve 2g of antioxidant 1010, 1g of co-antioxidant 168, and 5g of surfactant sodium dodecylbenzenesulfonate in 50ml of acetone solution. Add 680g of COC Topas 6013 particles and stir for 10min. Then dry at 60 degrees Celsius for later use.

[0109] S2. Take 50g of surface-modified carbon nanotubes and 100g of product S1 and grind them in a horizontal grinder for 25 minutes at a speed of 1500 rpm.

[0110] S3. Add the materials obtained in S1 and S2, along with 82g of toughening agent SEBS G1651 and 60g of dynamic bonding compatibilizer, to a high-speed mixer for high-speed mixing at 3200 rpm and 65℃.

[0111] S4. The material is fed into the twin-screw extruder, and ultrasonic assisted dispersion is turned on with a power of 400W and a frequency of 25kHz. The temperature of the mixing and feeding section is 200℃, the temperature of the melting section is 220℃, the temperature of the plasticizing section is 250℃, the temperature of the extrusion section is 250℃, and the screw speed is 300rpm.

[0112] S5. Add the granulated material into the injection molding machine. Set the barrel temperature of the injection molding machine to 240-270℃, the mold temperature to 80℃, and the injection pressure to 100MPa.

[0113] Example 3

[0114] In this embodiment, a cyclic olefin copolymer-based composite material for wafer transfer boxes is prepared. By weight, the composite material includes 76 parts of cyclic olefin copolymer, 5 parts of surface-modified carbon nanotubes, 8.2 parts of toughening agent, 10 parts of dynamic bonding compatibilizer, 0.2 parts of antioxidant 1010, 0.1 parts of auxiliary antioxidant, and 0.5 parts of surfactant.

[0115] S1. Dissolve 2g of antioxidant 1010, 1g of co-antioxidant 168, and 5g of surfactant sodium dodecylbenzenesulfonate in 50ml of acetone solution. Add 660g of COC Topas 6013 particles and stir for 10min. Then dry at 60 degrees Celsius for later use.

[0116] S2. Take 50g of surface-modified carbon nanotubes and 100g of product S1 and grind them in a horizontal grinder for 25 minutes at a speed of 1500 rpm.

[0117] S3. Add the materials obtained in S1 and S2, along with 82g of toughening agent SEBS G1651 and 100g of dynamic bonding compatibilizer, to a high-speed mixer for high-speed mixing at 3200 rpm and 65℃.

[0118] S4. The material is fed into the twin-screw extruder, and ultrasonic assisted dispersion is turned on with a power of 400W and a frequency of 25kHz. The temperature of the mixing and feeding section is 200℃, the temperature of the melting section is 220℃, the temperature of the plasticizing section is 250℃, the temperature of the extrusion section is 250℃, and the screw speed is 300rpm.

[0119] S5. Add the granulated material into the injection molding machine. Set the barrel temperature of the injection molding machine to 240-270℃, the mold temperature to 80℃, and the injection pressure to 100MPa.

[0120] Comparative Example 1

[0121] The only difference between this comparative example and Example 1 is that this comparative example does not use a dynamic bonding compatibilizer, and the dynamic bonding toughening agent is replaced with a mixture of COC-g-MAH and SEBS-g-GMA (mixing ratio 1:1.8). By weight, the composite material comprises 80 parts of COC Topas 6013, 5 parts of surface-modified carbon nanotubes, 8.2 parts of toughening agent, 6 parts of the mixture of COC-g-MAH and SEBS-g-GMA (mixing ratio 1:1.8), 0.2 parts of antioxidant 1010, 0.1 parts of auxiliary antioxidant, and 0.5 parts of surfactant.

[0122] Comparative Example 2

[0123] Compared with Example 1, this comparative example was prepared using a traditional blending modification method, the specific preparation method of which is as follows:

[0124] (1) Add 800g of cyclic olefin copolymer, 50g of surface-modified carbon nanotubes, 82g of toughening agent, 60g of dynamic link compatibilizer, 2g of antioxidant 1010, 1g of auxiliary antioxidant, and 5g of surfactant to a high-speed mixer and mix evenly.

[0125] (2) The uniformly mixed material is added to a twin-screw extruder for mixing, filtering, extrusion, underwater granulation and drying to obtain a resin composite material; the temperature of the mixing and feeding section is 200℃, the temperature of the melting section is 220℃, the temperature of the plasticizing section is 250℃, the temperature of the extrusion section is 250℃, and the screw speed is 300rpm; during extrusion granulation, the die head temperature is 250℃.

[0126] Comparative Example 3

[0127] Compared with Example 1, this comparative example uses unmodified carbon nanotubes instead of surface-modified carbon nanotubes, while the amounts of other raw materials and preparation methods are the same as in Example 1.

[0128] The mechanical properties of the composite materials prepared in the examples and comparative examples are shown in Table 1 below:

[0129] Table 1. Mechanical property data of examples and comparative examples

[0130]

[0131] As shown in the table above, the cyclic olefin copolymer-based composite material for wafer cassettes provided by this invention exhibits high tensile and impact strength. Examples 1, 2, and 3 added different amounts of dynamic linking compatibilizer. Increasing the amount of dynamic linking compatibilizer significantly improved both elongation at break and impact strength. Compared to Comparative Example 1, the addition of the dynamic linking compatibilizer improved the compatibility between the toughening agent and the matrix, and the impact strength reached 9 KJ / m. 2 This meets the mechanical requirements of wafer carrier applications. By using a dynamic bonding compatibilizer and a multi-stage dispersion processing method, the surface morphology of the part is improved, with no flow marks or pitting. In Comparative Example 1, the poor compatibility between the toughening agent and the matrix resin resulted in obvious flow marks on the part surface. Compared to Example 1, Comparative Example 2 did not use the solution-grinding-ultrasonic assisted dispersion processing method, resulting in poor dispersion of the components within the matrix, significant differences in mechanical properties, and obvious flow marks on the injection-molded part surface, as well as pitting caused by carbon nanotube agglomeration. Comparative Example 3 did not use surface-modified carbon nanotubes, leading to easy agglomeration of the carbon nanotubes themselves, poor dispersion in the polymer matrix, and stress concentration points formed by carbon nanotube agglomeration, reducing impact strength and resulting in pitting on the part surface.

[0132] Table 2 shows a comparison of the resistivity of each embodiment with that of the comparative embodiment. The embodiments show lower resistivity and more stable conductivity.

[0133] Table 2. Electrical performance data of the examples and comparative examples

[0134] Volume resistivity Ω·cm resistivity fluctuation % Example 1 <![CDATA[8.1*10 5 ]]> ±5 Example 2 <![CDATA[7.2*10 5 ]]> ±8 Example 3 <![CDATA[6.1*10 5 ]]> ±6 Comparative Example 1 <![CDATA[6.0*10 6 ]]> ±8 Comparative Example 2 <![CDATA[7.2*10 5 ~3.1*10 7 ]]> ±42 Comparative Example 3 <![CDATA[4.1*10 6 ~5.2*10 8 ]]> ±60

[0135] In summary, the composite material for wafer transport boxes provided by this invention uses cyclic olefin copolymers as the base material, imparting high cleanliness and low gas release to the modified material. Dynamically linking compatibilizers improve the compatibility between the matrix and toughening agents, thereby increasing the impact strength of the composite material and improving melt flow marks on the injection molded parts. By incorporating surface-modified carbon nanotubes, this invention not only improves the antistatic properties of the modified material but also introduces segments with good compatibility with the COC matrix to enhance the dispersion of carbon nanotubes in the matrix, reducing carbon nanotube agglomeration. This effectively dissipates static electricity generated during wafer transport, protecting the wafer from electrostatic contamination. The use of a "solution-grinding-ultrasonic assisted extrusion" processing method ensures stable dispersion of each component additive, guaranteeing product quality stability and uniformity.

[0136] Finally, it should be noted that the above embodiments are only used to describe preferred embodiments 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 various modifications and improvements made to the technical solutions of the present invention by means of modifications or equivalent substitutions should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A cyclic olefin copolymer based composite material for wafer carrier, comprising the following components: cyclic olefin copolymer 70-89wt%; preferably 75-85wt%; toughening agent 3-20wt%; preferably 5-15wt%; dynamic linking compatibilizer 5-15wt%; preferably 6-10wt%; carbon nanotube 2-8wt%; preferably 3-6wt%; primary antioxidant 0.1-0.4wt%; preferably 0.2-0.3wt%; secondary antioxidant 0.05-0.3wt%; preferably 0.1-0.2wt%; surfactant 0.1-1wt%; preferably 0.3-0.7wt%. The cyclic olefin copolymer is Topas 6013. The toughening agent comprises styrene-based thermoplastic elastomer which is hydrogenated styrene / butadiene block copolymer SEBS; preferably, the styrene content of the styrene-based thermoplastic elastomer is 20-40wt%, preferably 27-33wt%. The method for preparing the dynamic linking compatibilizer comprises the following steps: (1) COC-g-MAH preparation: mixing cyclic olefin copolymer, maleic anhydride and free radical initiator, and reacting in a twin-screw extruder; (2) SEBS-g-GMA preparation: mixing SEBS, glycidyl methacrylate and free radical initiator, and reacting in a twin-screw extruder; (3) dynamic linking compatibilizer preparation: mixing COC-g-MAH, SEBS-g-GMA and transesterification catalyst, and reacting in a twin-screw extruder. In the step (1), the cyclic olefin copolymer is Topas 6013; and / or, the weight ratio of cyclic olefin copolymer to maleic anhydride is 1:0.04-0.

08.

2. The composite material of claim 1, wherein, In the step (2), the SEBS is Kraton G1651; and / or, the weight ratio of SEBS to glycidyl methacrylate is 1:0.04-0.

08.

3. The composite material according to claim 1 or 2, characterized in that, In the step (3), the weight ratio of COC-g-MAH to SEBS-g-GMA is 1:1.5-2.

4. The composite material according to any one of claims 1 to 3, characterized in that, The surface modification method of the carbon nanotube comprises the following steps: dispersing carbon nanotube in acidic solution for oxidation treatment, and adding silane coupling agent for reaction. According to the proportion, S1. Dissolve the surfactant, primary antioxidant and secondary antioxidant in acetone, and uniformly disperse on the surface of cyclic olefin copolymer, and remove the solvent by heating; S2. Mix and grind the product of S1 and carbon nanotube to obtain powder; S3. Mix and uniformly disperse the product of S1, the product of S2, toughening agent and dynamic linking compatibilizer; 5. The composite material according to any one of claims 1 to 4, characterized in that, S4. Extrude and granulate the product of S3 by a twin-screw extruder.

6. The composite material according to any one of claims 1 to 5, characterized in that, 10. Use of the composite material of claim 1 or the composite material prepared by the method of any one of claims 2-9 for preparing wafer carrier, including front opening wafer carrier and wafer basket.

7. The composite material according to any one of claims 1 to 6, wherein ​ 8. The composite material according to any one of claims 1 to 7, characterized in that, ​ 9. A method of making the composite material of any one of claims 1-8, comprising the steps of: ​ ​ ​ ​ ​

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