High-air-tightness nano-injection-molding polyethylene terephthalate composite material and application thereof

Abstract

The application belongs to the field of composite materials and discloses a high-air-tightness nano-injection-molding polyethylene terephthalate composite material and application thereof. The composite material comprises the following components in percentage by weight: PCR PET 22-83%; PBT 3-7%; cyclic PBT 1-3%; polyaryl sulfone 2-8%; reactive toughening agent 1-8%; antioxidant 0-1%; release agent 0-1%; glass fiber 10-50%. The composite material can realize high PCR content, has high air tightness and high aluminum-plastic bonding force, and is smoothly stripped and stable in process. The problem of insufficient air tightness of the current PET nano-injection-molding material is solved.

Description

Technical Field

[0001] This invention belongs to the field of composite materials, and specifically relates to a high airtightness nano-injection molded polyethylene terephthalate composite material and its application. Background Technology

[0002] Nano-injection molding of mid-frames has become a mainstream technology for mid-to-high-end mobile phones in recent years. Whether it's an aluminum alloy mid-frame, stainless steel mid-frame, or titanium alloy mid-frame, antenna cut-out strips can be designed using nano-injection molding. Polybutylene terephthalate (PBT) is currently the most widely used plastic material in nano-injection molding due to its excellent overall performance. In addition, polyphenylene sulfide (PPS) and high-temperature polyamide (PPA) are also used in some products. With increasing environmental awareness and the promulgation of relevant regulations, the environmental requirements for raw materials in consumer electronics products are gradually increasing. Plastic products made from recycled consumer raw materials (PCR) are becoming increasingly popular in the market. However, for the plastic materials used in nano-injection molding, whether PBT, PPS, or PPA, the lack of a single large-scale consumer market and the scarcity of PCR raw materials make it difficult to produce PCR-type products.

[0003] Some companies achieve PCR in their final PBT products by adding a portion of PCR-grade polyethylene terephthalate (PET). However, this method yields a low PCR content, generally not exceeding 20%. Otherwise, due to the slow crystallization and susceptibility to thermal decomposition of PET, defects such as difficulty in injection molding and demolding, and decreased material performance can occur, severely impacting product performance. An improved method is to use specially modified PET as the main component to replace PBT, achieving a high PCR content. However, PET-based materials suffer from insufficient airtightness during use. Airtightness directly relates to the final waterproof performance of the product, and with the increasing trend of higher waterproof ratings in consumer electronics, existing PET products cannot fully meet the waterproof performance requirements. Summary of the Invention

[0004] To overcome the shortcomings and deficiencies of the prior art, the primary objective of this invention is to provide a high-airtightness nano-injection molded polyethylene terephthalate (PET) composite material that achieves high PCR content while possessing high airtightness and high aluminum-plastic bonding strength, and exhibits smooth demolding and stable processing. This solves the problem of insufficient airtightness in current PET nano-injection molding materials.

[0005] Another objective of this invention is to provide a method for preparing the above-mentioned high airtightness nano-injection molded polyethylene terephthalate composite material.

[0006] Another objective of this invention is to provide the application of the above-mentioned high airtightness nano-injection molded polyethylene terephthalate composite material in smartphones and consumer electronics products.

[0007] The objective of this invention is achieved through the following solution:

[0008] A high-airtightness nano-injection molded PET composite material, comprising the following components by weight percentage:

[0009] PCR PET 22%-83%;

[0010] PBT 3%-7%;

[0011] Circular PBT 1%-3%;

[0012] Polyarylsulfone (PPSU) 2%-8%;

[0013] Reactive toughening agents 1%-8%;

[0014] Antioxidant 0-1%;

[0015] Release agent 0-1%;

[0016] 10%-50% glass fiber.

[0017] Preferably, the above-mentioned high airtightness nano-injection molded PET composite material comprises the following components by weight percentage:

[0018] PCR PET: 39%-67.6%;

[0019] PBT 4%-6%;

[0020] Circular PBT 2%;

[0021] Polyarylsulfone (PPSU) 4%-6%;

[0022] Reactive toughening agents 2%-6%;

[0023] Antioxidant 0.2%-0.5%;

[0024] Release agent 0.2%-0.5%;

[0025] 20%-40% glass fiber.

[0026] Preferably, the PCR PET has a melting point of 245-260℃ and an intrinsic viscosity of 0.7-0.9 dL / g.

[0027] Preferably, the intrinsic viscosity of the PBT is 0.6-0.8 dL / g.

[0028] Preferably, the cyclic PBT is cyclic butylene terephthalate (CBT), which has a degree of polymerization of less than 10 repeating units.

[0029] Preferably, the PPSU is a powdered raw material with a particle size of less than 100 mesh.

[0030] Preferably, the reactive toughening agent is a toughening agent containing glycidyl ether, and more preferably, it is a copolymer of ethylene methyl acrylate methacrylate glycidyl ether.

[0031] The antioxidant is at least one of hindered phenolic antioxidants and phosphite antioxidants, preferably antioxidant 1010; the release agent is at least one of polyvinyl alcohol and long-chain fatty acid esters, preferably PETS.

[0032] A method for preparing the above-mentioned high airtightness nano-injection molded PET composite material includes the following steps: mixing the components and extruding and granulating them through an extruder at a granulation temperature of 200-280℃.

[0033] The aforementioned high airtightness nano-injection molded PET composite materials are used in the manufacture of mobile phones and consumer electronics products, especially in the application of nano-injection molded aluminum alloy frames.

[0034] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0035] The PET composite material of this invention can achieve high PCR content while possessing high airtightness and high aluminum-plastic bonding strength, and exhibits smooth demolding and stable processing. Furthermore, the preparation method of this invention is simple and easy to implement, making it suitable for large-scale production. Attached Figure Description

[0036] Figure 1 This is a structural diagram of the plastic test component, where 1 represents the aluminum alloy part and 2 represents the plastic part.

[0037] Figure 2 A schematic diagram of the structure of the plastic-aluminum alloy test component used for airtightness testing. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto. Unless otherwise specified in the embodiments, the conditions are performed according to conventional conditions or the manufacturer's recommended conditions. Reagents or instruments used without specified manufacturers are all commercially available conventional products. Specifically: PCR PET was Linuo PCR PET810-NA (viscosity 0.8 dL / g), low-viscosity PET was Sinopec FC510A (viscosity 0.67 dL / g), PBT was Changchun Chemical 1200-211D (viscosity 0.75 dL / g), cyclic PBT was Cyclics CBT100, PPSU was Solvay Radel R-5000, glass fiber was Chongqing International ECS3031H, ethylene methyl acrylate glycidyl ether copolymer was Arkema AX8900, antioxidant 1010 was Tianjin Lianlong 1010, and the release agent pentaerythritol tetrastearate (PETS) was purchased from Hubei Longxin Chemical Co., Ltd.

[0039] All materials used in the examples were purchased and used directly without any processing. The PPSU powder in the examples was purchased and then ground, with the particle size range of the ground PPSU being less than 100 mesh.

[0040] The tensile strength in the following examples was tested using the ISO 527 standard method, and the notched impact strength was tested using the ISO 180 standard method.

[0041] The aluminum alloy nano-injection molded sample used in this invention is prepared by the following process: 6061 aluminum material, with dimensions of 45mm in length, 18mm in width, and 1.6mm in thickness; T-treatment process: sequentially alkali washing with NaOH solution (1mol / L, 20 seconds), hydrochloric acid etching (1mol / L, 4 minutes), and immersion in ammonia solution (T-treatment solution, 0.6mol / L, 2 minutes). Then, the sample is cleaned with water and dried to obtain an aluminum sample sheet with nanopores on the surface.

[0042] Preparation of the plastic-metal test assembly used in this invention:

[0043] In this invention, a plastic-metal test assembly is prepared according to the method described in Japanese Taisei Chemical Patent US8057890(B2). Specifically, as follows: Figure 1 This is a schematic diagram of the overall structure of the plastic-metal test component. The metal sheet measures 18mm × 45mm × 1.6mm, the plastic part measures 10mm × 45mm × 3mm, and the bonding area between the plastic and metal is 0.5cm². 2 In all experiments, the same injection molding conditions were maintained: barrel temperature 265-280℃ and mold temperature 150℃. PET composite material was injected onto a metal sheet to obtain a plastic-metal test part.

[0044] Plastic-metal bonding strength test:

[0045] The plastic-metal adhesion test standard used in this invention refers to the standard in Japanese Taisei Chemical Patent US8057890(B2), where the bonding area between the plastic and metal is 0.5 cm². 2 A biaxial tensile test was performed on the plastic-metal test component.

[0046] The fabrication of the plastic-aluminum alloy test piece used for the airtightness test is as follows: Figure 2 The diagram shows the structure. The aluminum alloy sheet measures 18mm × 45mm × 1.6mm, and the plastic part is a circle with a diameter of 60mm and a thickness of 2mm. The plastic part is injection molded and combined with the aluminum alloy. The barrel temperature is 265-280℃, and the mold temperature is 150℃. The testing equipment is a ZQJ-3000 from Zhongke Keyi, and the test gas is helium.

[0047] The processing performance test method is as follows: Using a single-gate 60*60*2mm mold, injection temperature 270°C, mold temperature 150°C, and a molding cycle of 40 seconds, 13 molds were continuously injected. The first 3 molds were discarded, and counting started from the 4th mold. If all 10 molds could automatically demold, the processing performance was excellent. If the 7th-9th molds could automatically demold, the processing performance was average. If the 0th-6th molds could automatically demold, the processing performance was poor.

[0048] Examples 1-11

[0049] The PET composite materials in Examples 1-11 were all prepared by the following steps: weighing the components according to the applicable weight percentage (%), mixing the components, and granulating them using a twin-screw extruder to obtain the PET composite at a granulation temperature of 240-280℃. The weight percentage (%) of each component in Examples 1-11 and the various properties of the prepared PET composite materials are shown in Table 1 below.

[0050] Table 1. Weight percentage (%) of raw materials for PET composite materials, along with product performance and processing properties.

[0051]

[0052] As shown in Table 1, when cyclic PBT is not used, although the bonding strength and processing performance of aluminum can meet production requirements (it is generally believed that 35MPa can meet most production needs), the airtightness of the product is insufficient (it is generally believed that airtightness reaches E...). -9 (The order of magnitude is sufficient to meet the requirements). When a certain amount of cyclic PBT was added (Examples 8-10), the airtightness was significantly improved, while maintaining the bonding strength and processing performance of the aluminum metal.

[0053] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A high-airtightness nano-injection molded PET composite material, characterized in that... The components include the following weight percentages: PCR PET 22%-83%; PBT 3%-7%; Circular PBT 1%-3%; PPSU 2%-8%; Reactive toughening agents 1%-8%; Antioxidant 0-1%; Release agent 0-1%; 10%-50% glass fiber.

2. The high airtightness nano-injection molded PET composite material according to claim 1, characterized in that... The components include the following weight percentages: PCR PET: 39%-67.6%; PBT 4%-6%; Circular PBT 2%; PPSU 4%-6%; Reactive toughening agents 2%-6%; Antioxidant 0.2%-0.5%; Release agent 0.2%-0.5%; 20%-40% glass fiber.

3. The high airtightness nano-injection molded PET composite material according to claim 1 or 2, characterized in that: The cyclic PBT is cyclic butylene terephthalate, with a degree of polymerization of less than 10.

4. The high airtightness nano-injection molded PET composite material according to claim 1 or 2, characterized in that: The PCR PET has a melting point of 245-260℃ and an intrinsic viscosity of 0.7-0.9 dL / g.

5. The high airtightness nano-injection molded PET composite material according to claim 1 or 2, characterized in that: The intrinsic viscosity of the PBT is 0.6-0.8 dL / g.

6. The high airtightness nano-injection molded PET composite material according to claim 1 or 2, characterized in that: The PPSU is a powdered raw material with a particle size of less than 100 mesh.

7. The high airtightness nano-injection molded PET composite material according to claim 1 or 2, characterized in that: The reactive toughening agent is a toughening agent containing glycidyl ether; The antioxidant is at least one of hindered phenolic antioxidants and phosphite antioxidants; the release agent is at least one of polyvinyl alcohol and long-chain fatty acid esters.

8. The high airtightness nano-injection molded PET composite material according to claim 7, characterized in that: The reactive toughening agent is an ethylene methyl acrylate glycidyl ether copolymer.

9. The high airtightness nano-injection molded PET composite material according to claim 7, characterized in that: The antioxidant is antioxidant 1010; the mold release agent is PETS.

10. A method for preparing a high-airtightness nano-injection molded PET composite material according to any one of claims 1-9, characterized in that... The process includes the following steps: mixing the components and extruding them into granules using an extruder at a granulation temperature of 200-280℃.

11. The application of the high airtightness nano-injection molded PET composite material according to any one of claims 1-9 in the manufacture of consumer electronics products.

12. The application of the high airtightness nano-injection molded PET composite material according to any one of claims 1-9 in nano-injection molded aluminum alloy frames.

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