PET / PBT alloy and preparation method thereof

Abstract

The invention discloses a PET / PBT (Polyethylene Terephthalate / Polybutylene Terephthalate) alloy and a preparation method thereof. The PET / PBT alloy is prepared from the following raw materials: PET resin, PBT resin, flame-retardant ACR (Acrylics) resin, GMA-g-EMA-g-SiO2, epoxy POSS (Polyhedral Oligomeric Silsesquioxane), modified copper chromite black, modified tin oxide and a phosphite antioxidant. The PET / PBT alloy has excellent mechanical property, flame retardant property, low dielectric property and laser forming property, and can be widely applied to the field of communication requiring laser forming property.

Description

Technical Field

[0001] The present invention belongs to the field of materials, and particularly relates to a PET / PBT alloy and a preparation method thereof. Background Art

[0002] Laser direct structuring (LDS) functional materials are a kind of special engineering plastics modified based on metal compounds or complexes. Through the synergistic effect of laser activation and electroless plating technology, metal conductive circuits can be precisely constructed on the surface of three-dimensional injection-molded parts to form molded interconnected devices (3D-MIDs) with a three-dimensional circuit structure. Its manufacturing process mainly includes five core links: first, a functional base material is prepared through material formulation design and modification, and then injection-molded into a three-dimensional structural part; a preset area is selectively activated by laser to form catalytic active points, and then the precise deposition of a metal layer is achieved through an electroless plating process; finally, device integration is completed through surface spraying and electronic component assembly. This technology breaks through the physical limitations of traditional two-dimensional circuit boards and shows significant advantages in fields such as 5G communication antennas, smart wearable devices, micro medical sensors, Internet of Things terminals, and unmanned aerial vehicle navigation systems, promoting the innovation of smart devices towards the integration of structure and function, lightweight, and miniaturization.

[0003] The blending of PET and PBT can bring out the synergistic effect of the two, and its advantages are as follows: the high strength and heat resistance (higher glass transition temperature) of PET are complementary to the fast crystallinity and processing fluidity of PBT. After blending, it can not only improve the rigidity and dimensional stability of the material, but also solve the problem of long molding cycle caused by the slow crystallization rate of pure PET. At the same time, it reduces the defect of easy warping of pure PBT, and the comprehensive mechanical properties are more balanced; in addition, the chemical structures of the two are similar, with good compatibility, and the blending process is relatively simple and the cost is controllable.

[0004] At present, a number of technical solutions have been formed for the research on PET / PBT alloys. Chinese Patent CN105623206A discloses a polyester composition for NMT with LDS function and its preparation method. The polyester composition for NMT with LDS function mainly consists of the following raw materials by mass: 40-90 parts of polyester; 10-40 parts of PCT resin; 0.1-5 parts of transesterification inhibitor; 10-40 parts of glass fiber; 3-30 parts of inorganic whiskers; 3-15 parts of LDS auxiliary agent; 0.3-5 parts of heat oxygen stabilizer; 3-15 parts of toughening agent. Chinese Patent CN116390988A discloses a thermoplastic composition, which includes: (a) about 1 wt% to about 99 wt% of at least one crystalline polyester; (b) about 1 wt% to about 99 wt% of a polycarbonate copolymer; (c) about 10 wt% to about 50 wt% of reinforcing filler; and (d) about 1 wt% to about 10 wt% of a laser direct structuring (LDS) additive. In a specific aspect, the at least one crystalline polyester includes polybutylene terephthalate (PBT), and the polycarbonate copolymer includes a polycarbonate-siloxane (PC-Si) copolymer. Chinese Patent CN104629273A discloses a polyester composite material that can be simultaneously applied to NMT process and LDS process, including the following components in weight percentages: 30%-70% of PBT resin, 3%-20% of polyolefin, 1%-15% of metal compound, 0.05%-0.5% of antioxidant, 0.1%-2.0% of demolding agent, 10%-40% of glass fiber. It is worth noting that the above technical solutions all focus on realizing the laser activation function through metal oxides, but none of them specifically regulate the dielectric properties of the materials. This technical gap may limit the application expansion of the materials in fields sensitive to dielectric characteristics such as high-frequency electronic devices. Summary of the Invention

[0005] Based on this, one of the purposes of the present invention is to provide a PET / PBT alloy, which has excellent mechanical properties, flame retardant properties, low dielectric properties and laser forming properties, and can be widely applied to the communication field that requires laser forming properties.

[0006] The specific technical solutions to achieve the above invention purposes are as follows.

[0007] A PET / PBT alloy is prepared from the following raw materials in parts by weight:

[0008] 70-90 parts of PET resin,

[0009] 10-30 parts of PBT resin,

[0010] The total weight parts of the PET resin and the PBT resin are 100 parts,

[0011]

[0012] The GMA-g-EMA-g-SiO2 is ethylene-methyl acrylate copolymer grafted with glycidyl methacrylate and silica.

[0013] In some embodiments, the PET / PBT alloy is prepared from the following raw materials in parts by weight:

[0014] PET resin 75 - 85 parts,

[0015] PBT resin 15 - 25 parts,

[0016] The sum of the parts by weight of the PET resin and the PBT resin is 100 parts.

[0017]

[0018] In some embodiments, the PET / PBT alloy is prepared from the following raw materials in parts by weight:

[0019] PET resin 78 - 82 parts,

[0020] PBT resin 18 - 22 parts,

[0021] The sum of the parts by weight of the PET resin and the PBT resin is 100 parts.

[0022]

[0023] In some embodiments, the intrinsic viscosity of the PET resin is 0.65 dL / g - 0.75 dL / g, measured according to the standard of GB / T 1632.5 - 2008, and the solvent is 2-chlorophenol; the intrinsic viscosity of the PBT resin is 0.8 dL / g - 0.9 dL / g, measured according to the standard of GB / T 1632.5 - 2008, and the solvent is 2-chlorophenol.

[0024] In some embodiments, the modified copper chromite black is obtained by organically modifying copper chromite black with γ-(2,3-epoxypropoxy)propyltrimethoxysilane; the modified tin oxide is obtained by organically modifying tin oxide with γ-(2,3-epoxypropoxy)propyltrimethoxysilane; the phosphite antioxidant is tetra(2,4-di-tert-butylphenyl)-4,4'-biphenyldiphosphite.

[0025] In some embodiments, the preparation method of the flame-retardant ACR resin comprises the following steps:

[0026] (1) Mix 90 g to 96 g of octamethylcyclotetrasiloxane, 7 g to 11 g of γ-methacryloxypropyltrimethoxysilane, 2 g to 3 g of dodecylbenzenesulfonic acid, and 150 mL to 200 mL of deionized water, and perform pre-emulsification for 0.3 h to 0.7 h at a stirring speed of 300 rpm to 500 rpm. Then add 0.9 g to 1.3 g of dodecylbenzenesulfonic acid and 400 mL to 600 mL of deionized water, heat in a constant temperature water bath to 75°C to 95°C, and maintain a rotation speed of 150 rpm to 250 rpm. After reacting for 2 h to 4 h, cool down to obtain a polysiloxane core emulsion; adjust the pH value of the polysiloxane core emulsion to 7.8 to 8.2 using a 2 wt% to 4 wt% sodium hydroxide solution. After adjustment, add 1.7 g to 2.7 g of potassium persulfate dropwise to the polysiloxane core emulsion;

[0027] (2) Mix 80 g to 90 g of diethyl methylphosphonate acrylate, 140 g to 180 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide grafted acrylate monomer, 2 g to 3 g of sodium dodecyl sulfate, and 300 mL to 500 mL of deionized water, and perform pre-emulsification for 0.3 h to 0.7 h at a stirring speed of 300 rpm to 500 rpm. Then add dropwise to the polysiloxane core emulsion obtained in the above step (1) whose temperature has been raised to 75°C to 85°C. After adding dropwise, add 1.1 g to 1.5 g of potassium persulfate as a supplement. After reacting for 2 h to 4 h, cool down, discharge, demulsify, and filter to obtain the product.

[0028] In some of the embodiments, the preparation method of the GMA-g-EMA-g-SiO2 includes the following steps: Add 100 g of SiO2 containing amino groups to 500 mL to 700 mL of N,N-dimethylformamide, and perform ultrasonic treatment for 10 min to 20 min to obtain a uniform dispersion; dissolve 60 g to 80 g of GMA-g-EMA in 200 mL to 400 mL of N,N-dimethylformamide to obtain an N,N-dimethylformamide solution of GMA-g-EMA; stir the dispersion at a rotation speed of 300 rpm to 500 rpm, and slowly add dropwise the N,N-dimethylformamide solution of GMA-g-EMA at 85°C to 95°C, and keep the reaction conditions unchanged for condensation reflux for 10 h to 14 h; centrifuge the reacted solution, wash with absolute ethanol, and dry at 55°C to 65°C for 10 h to 14 h to obtain GMA-g-EMA-g-SiO2.

[0029] Another object of the present invention is to provide a preparation method of the above PET / PBT alloy.

[0030] The specific technical solutions for achieving the above invention object include the following.

[0031] A preparation method of a PET / PBT alloy, comprising the following steps:

[0032] (1) Place the PET resin and PBT resin at a temperature of 110°C to 120°C and dry for 2 hours to 4 hours, then cool; add the cooled PET resin, PBT resin, flame-retardant ACR resin and phosphite antioxidant to a blender for mixing;

[0033] (2) Add the GMA-g-EMA-g-SiO2, epoxy POSS, modified copper chromite black, and modified tin oxide to another high-speed blender for mixing;

[0034] (3) Add the mixture prepared in step (1) to a parallel twin-screw extruder through a feeder, and add the mixture prepared in step (2) laterally (for example, in the third zone) of the parallel twin-screw extruder (a total of eight zones) for melt extrusion and pelletization. The process parameters include: the temperature of the first zone is 240°C to 260°C, the temperature of the second zone is 245°C to 265°C, the temperature of the third zone is 245°C to 265°C, the temperature of the fourth zone is 250°C to 270°C, the temperature of the fifth zone is 250°C to 270°C, the temperature of the sixth zone is 255°C to 275°C, the temperature of the seventh zone is 260°C to 280°C, the temperature of the eighth zone is 260°C to 280°C, the die temperature is 255°C to 275°C, and the screw speed is 400 rpm to 800 rpm.

[0035] In some embodiments, the preparation method of the PET / PBT alloy comprises the following steps:

[0036] (1) Place the PET resin and PBT resin at a temperature of 113°C to 117°C and dry for 1.5 hours to 3.5 hours, then cool; add the cooled PET resin, PBT resin, flame-retardant ACR resin and phosphite antioxidant to a blender for mixing;

[0037] (2) Add the GMA-g-EMA-g-SiO2, epoxy POSS, modified copper chromite black, and modified tin oxide to another high-speed blender for mixing;

[0038] (3) Add the mixture prepared in step (1) into a parallel twin-screw extruder through a feeder, and add the mixture prepared in step (2) laterally (for example, in the third zone) of the parallel twin-screw extruder (with a total of eight zones) for melt extrusion and granulation. The process parameters include: the temperature of the first zone is 245°C to 255°C, the temperature of the second zone is 250°C to 260°C, the temperature of the third zone is 250°C to 260°C, the temperature of the fourth zone is 255°C to 265°C, the temperature of the fifth zone is 255°C to 265°C, the temperature of the sixth zone is 260°C to 270°C, the temperature of the seventh zone is 265°C to 275°C, the temperature of the eighth zone is 265°C to 275°C, the die head temperature is 260°C to 270°C, and the screw speed is 500 rpm to 700 rpm.

[0039] In some of the embodiments, the screw shape of the parallel twin-screw extruder is single-threaded; the ratio of the screw length L to the diameter D, L / D, is 35 to 55; and there is more than 1 (including 1) kneading block zone and more than 1 (including 1) reverse-thread zone on the screw.

[0040] In some of the embodiments, the ratio of the screw length L to the diameter D, L / D, is 40 to 50; and there are 2 kneading block zones and 1 reverse-thread zone on the screw.

[0041] In some of the embodiments, in step (1) and / or step (2), the mixer is a high-speed mixer with a rotation speed of 500 revolutions per minute to 1500 revolutions per minute.

[0042] The functions of the respective raw materials of the PET / PBT alloy of the present invention are as follows:

[0043] The present invention improves the flame retardancy of the PET / PBT alloy by compounding and using a flame retardant ACR resin, GMA-g-EMA-g-SiO2, and epoxy POSS. Among them, (1) for the flame retardant ACR resin, by utilizing the synergistic flame retardant effect of P-Si and the toughening structure characteristics of ACR, siloxane is selected as the core layer, phosphorus-containing acrylate monomer as the shell layer, and silane coupling agent (γ-methacryloxypropyltrimethoxysilane) as the crosslinking agent. By inhibiting the generation and growth of microcracks, the impact performance of the material is improved. At the same time, the flame retardant ACR resin can play a role in flame retarding the PET / PBT alloy in the gas phase and condensed phase; (2) GMA-g-EMA-g-SiO2 is prepared by grafting ethylene-methyl acrylate copolymer grafted glycidyl methacrylate (GMA-g-EMA) onto the surface of nano-SiO2, obtaining a nano-SiO2 with amphiphilic properties. The methyl acrylate structural unit of this GMA-g-EMA-g-SiO2 has good compatibility with the PET / PBT alloy, and the epoxy group can react with the terminal hydroxyl groups of the PET resin and PBT resin, improving the interfacial adhesion and compatibility of the PET resin and PBT resin. At the same time, GMA-g-EMA-g-SiO2 can form a continuous silicon-containing carbon layer at the interface, inhibiting the decomposition of the PET resin and PBT resin, playing a role in synergistic flame retardancy; (3) As a typical organosilicon-based flame retardant, epoxy POSS can effectively flame retard the PET / PBT alloy in its compound flame retardant system. The terminal groups of epoxy POSS contain epoxy groups, and these epoxy groups can react with the terminal hydroxyl groups of the PET resin and PBT resin, thereby improving the dispersibility and compatibility of epoxy POSS in the PET resin and PBT resin materials, and ultimately enhancing the flame retardancy of the PET / PBT alloy. Epoxy POSS has low dielectric properties. Under the condition that the test frequency is 5 GHz, its dielectric constant is only 2.1 - 2.4. This characteristic mainly stems from the unique cage-like three-dimensional structure of POSS. The center of this structure is an inorganic core composed of alternating silicon-oxygen (Si-O) connections, and the silicon atoms at the eight vertices are respectively connected with organic substituents (R groups). This cage-like structure allows for a large space inside the molecule, making it impossible for molecules to be closely packed, thereby reducing the degree of molecular polarization. When an electric field acts, the molecules are difficult to be polarized, and the dielectric constant decreases accordingly. The Si-O bond has a relatively high bond energy of 445.2 kJ / mol. In contrast, the bond energy of the C-C bond is 350.7 kJ / mol, and the bond energy of the C-O bond is 359.1 kJ / mol. The Si-O bond is more difficult to be broken. Therefore, in an electric field, the vibration and rotation of the Si-O bond are less affected, and the response to the electric field weakens, which further reduces the dielectric constant.

[0044] The present invention innovatively constructs a laser direct structuring (LDS) enhancement system based on interfacial chemical bonding and functional synergy. The core breakthrough lies in: through double interfacial modification of copper chromite black and tin oxide with γ-(2,3-epoxypropoxy) propyltrimethoxysilane, the synergistic effect of laser activation - electroless metallization of PET / PBT alloy is realized. The innovation of the principle is reflected in: (1) the nano-dispersion mechanism induced by chemical bonding: the epoxy groups of the modified filler undergo ring-opening reactions with the terminal hydroxyl groups of the PET / PBT alloy to form a covalent crosslinking network, breaking through the limitation of weak interfacial interactions in traditional physical blending, enabling copper chromite black / tin oxide to achieve nano-scale uniform dispersion (particle size <50 nm) in the matrix, and eliminating the heterogeneity of laser absorption; (2) the dual laser-catalytic response characteristics of copper chromite black: the d-d electron transition characteristics of its spinel crystal structure precisely match the 1064 nm laser wavelength, and through the local surface plasmon resonance effect, the photon energy is efficiently converted into heat energy, inducing the formation of micron-scale activation pits on the PET / PBT alloy matrix; simultaneously, the exposed CuCr2O4(111) crystal plane can serve as a highly active catalytic site, reducing the reduction activation energy of Cu 2+ in the electroless plating solution from 0.85 eV to 0.28 eV, driving the preferential nucleation and epitaxial growth of metal ions on the laser track; (3) the construction of a pre-conductive network of tin oxide: SnO2 forms a continuous electron transport channel (carrier density >10 18 cm -3 ) through the modified interface, and forms an Ohmic contact interface with gradient energy level matching with the deposited metal during the electroless plating process, reducing the metal / matrix interface resistance to the level of 10 -4 Ω·cm 2 , which is 3 orders of magnitude lower than that of the traditional system. The technological breakthrough is manifested as: under the synergistic action of the two components, the metal deposition rate of the laser track is increased to 8 μm / min (240% higher than that of the single-component system), and the fine line resolution breaks through 15 μm line width, providing a disruptive solution for the micro-interconnection of precision electronic devices such as 5G millimeter-wave antennas.

[0045] Tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenyldiphosphite, as an efficient phosphite antioxidant, plays a synergistic antioxidant role through multiple mechanisms in the blending process of PET / PBT alloy. Among them, the phosphite group in the antioxidant molecule can preferentially react with the hydroperoxides (ROOH) generated during the processing, convert them into stable alcohols (ROH), and block the propagation of free radical chain oxidation reactions; the steric hindrance effect of the biphenyl rigid skeleton and four 2,4-di-tert-butylphenyl groups endows it with excellent thermal stability (decomposition temperature >350 °C), and it can still maintain structural integrity during the high-temperature melting processing of PET / PBT alloy; at the same time, the phosphorus atom in the molecule captures metal ion impurities (such as residual catalysts) through coordination, inhibiting metal-catalyzed oxidation reactions.

[0046] Compared with the prior art, the PET / PBT alloy provided by the present invention and its preparation method have the following beneficial effects:

[0047] 1. In the present invention, the flame retardant performance of the PET / PBT alloy is improved by compounding and using a flame retardant ACR resin, GMA-g-EMA-g-SiO2, and epoxy POSS. The laser direct moldability of the PET / PBT alloy is improved by compounding and using modified copper chromite black and modified tin oxide. At the same time, the low dielectric performance of the PET / PBT alloy is achieved through epoxy POSS, and the compatibility and toughness of the PET / PBT alloy are improved by GMA-g-EMA-g-SiO2. Moreover, the epoxy groups of GMA-g-EMA-g-SiO2, modified copper chromite black, and modified tin oxide can react with the terminal hydroxyl groups of the PET / PBT alloy, improving the dispersibility and compatibility of the modified copper chromite black and modified tin oxide in the PET / PBT alloy material, thereby improving the mechanical properties, flame retardant performance, low dielectric performance, and laser molding performance of the PET / PBT alloy. The phosphite antioxidant tetra(2,4-di-tert-butylphenyl)-4,4'-biphenyldiphosphite is used to improve the thermal stability and antioxidant properties of the PET / PBT alloy during processing and use.

[0048] 2. The preparation method of the PET / PBT alloy of the present invention has a simple process, is easy to control, has low requirements for equipment, and the equipment used is all general polymer processing equipment, with low investment, which is conducive to industrial production. Brief Description of the Drawings

[0049] Figure 1 It is the process flow chart of the preparation of the PET / PBT alloy of the present invention. Detailed Embodiments

[0050] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the drawings. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosed content of the present invention more thorough and comprehensive.

[0051] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention are only for the purpose of describing specific embodiments and are not used to limit the present invention. The term "and / or" used in the present invention includes any and all combinations of one or more of the related listed items.

[0052] The reaction mechanism of the PET / PBT alloy of the present invention is as follows (please refer to the process flow chart for the preparation process in Figure 1 ):

[0053]

[0054] Among them, R1 is PET resin or PBT resin; R2 is GMA-g-EMA-g-SiO2, or modified copper chromite black, or modified tin oxide.

[0055] It can be seen from the above reaction formula that the epoxy groups of GMA-g-EMA-g-SiO2, modified copper chromite black, and modified tin oxide can react with the terminal hydroxyl groups of PET resin and PBT resin, improving the dispersibility and compatibility of modified copper chromite black and modified tin oxide in the PET / PBT alloy material, thereby preparing a PET / PBT alloy with excellent mechanical properties, flame retardancy, low dielectric properties, and laser forming properties.

[0056] The raw materials used in the examples and comparative examples of the present invention are as follows:

[0057] PET resin with an intrinsic viscosity of 0.7 dL / g, purchased from Xinjiang Blueshirt Tunhe Technology Co., Ltd.

[0058] PBT resin with an intrinsic viscosity of 0.85 dL / g, purchased from Xinjiang Blueshirt Tunhe Technology Co., Ltd.

[0059] Octamethylcyclotetrasiloxane, purchased from Zhongshan Dixin Chemical Co., Ltd.

[0060] γ-Methacryloxypropyltrimethoxysilane, purchased from Hubei Jusheng Technology Co., Ltd.

[0061] Dodecylbenzenesulfonic acid, purchased from Guangzhou Yuanda New Materials Co., Ltd.

[0062] Sodium hydroxide, purchased from Sinopharm Chemical Reagent Co., Ltd.

[0063] Diethyl methylphosphonate acrylate, purchased from Zhengzhou Alpha Chemical Co., Ltd.

[0064] 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide grafted acrylate monomer, purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.

[0065] Sodium dodecyl sulfate, purchased from Hunan Yunbang Biotechnology Co., Ltd.

[0066] Potassium persulfate, purchased from Sinopharm Chemical Reagent Co., Ltd.

[0067] SiO2 with terminal amino groups, purchased from Hubei Huifu Nanomaterials Co., Ltd.

[0068] N,N-Dimethylformamide, purchased from Changzhou Wanyirun Chemical Co., Ltd.

[0069] GMA-g-EMA, purchased from Shenyang Ketong Plastic Co., Ltd.

[0070] Absolute ethanol, purchased from Sinopharm Chemical Reagent Co., Ltd.

[0071] Epoxy-functional POSS with epoxy groups at the end groups, selected from Hybrid Plastics Company, USA.

[0072] Modified basic copper phosphate, purchased from Hubei Xin Hongli Chemical Co., Ltd.

[0073] Modified tin oxide, purchased from Nanjing Kailinston Chemical Technology Co., Ltd.

[0074] Tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenyldiphosphite, purchased from Hubei Xinkang Pharmaceutical Chemical Co., Ltd.

[0075] The preparation method of the flame-retardant ACR resin used in the following examples and comparative examples includes the following steps:

[0076] (1) Mix 93 g of octamethylcyclotetrasiloxane, 9 g of γ-methacryloxypropyltrimethoxysilane, 2.5 g of dodecylbenzenesulfonic acid and 175 mL of deionized water, and carry out pre-emulsification for 0.5 h at a stirring speed of 400 rpm. Then add 1.1 g of dodecylbenzenesulfonic acid and 500 mL of deionized water, heat in a constant temperature water bath to 85 °C, and maintain the rotation speed at 200 rpm. After reacting for 3 h, cool down to obtain a polysiloxane core emulsion; adjust the pH value of the polysiloxane core emulsion to 8.0 with 3 wt% sodium hydroxide solution. After adjustment, add 2.2 g of potassium persulfate dropwise to the polysiloxane core emulsion;

[0077] (2) Mix 85 g of diethyl methylphosphonate acrylate, 160 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide grafted acrylate monomer, 2.5 g of sodium dodecyl sulfate and 400 mL of deionized water, and carry out pre-emulsification for 0.5 h at a stirring speed of 400 rpm, and then dropwise add it to the polysiloxane core emulsion obtained in the above step (1) whose temperature has been raised to 80 °C. After the dropping is completed, add 1.3 g of potassium persulfate, cool down and discharge after reacting for 3 h, demulsify, and filter to obtain.

[0078] The preparation method of GMA-g-EMA-g-SiO2 used in the following examples and comparative examples includes the following steps: Add 100 g of SiO2 containing amino groups to 600 mL of N,N-dimethylformamide, and ultrasonically treat for 15 min to obtain a uniform dispersion; Dissolve 70 g of GMA-g-EMA in 300 mL of N,N-dimethylformamide to obtain an N,N-dimethylformamide solution of GMA-g-EMA; Stir the dispersion at a speed of 400 rpm, and slowly drop the N,N-dimethylformamide solution of GMA-g-EMA at 90 °C, and keep the reaction conditions unchanged for reflux condensation for 12 h; Centrifuge the reaction solution, wash with absolute ethanol, and dry at 60 °C for 12 h to obtain GMA-g-EMA-g-SiO2.

[0079] The present invention will be described in detail below with reference to the accompanying drawings and specific examples.

[0080] Example 1 PET / PBT alloy and its preparation method

[0081] The PET / PBT alloy of this example is prepared from the following raw materials by weight:

[0082]

[0083]

[0084] The phosphite antioxidant is tetra(2,4-di-tert-butylphenyl)-4,4'-biphenyldiphosphite.

[0085] Please refer to Figure 1 , The preparation method of the PET / PBT alloy of this example includes the following steps:

[0086] (1) Place the PET resin and PBT resin at a temperature of 110 °C and dry for 4 hours, then cool; Add the cooled PET resin, PBT resin, flame-retardant ACR resin, and phosphite antioxidant to a blender for mixing;

[0087] (2) Add the GMA-g-EMA-g-SiO2, epoxy POSS, modified copper chromite black, and modified tin oxide to another high-speed blender for mixing;

[0088] (3) Add the mixture prepared in step (1) into a parallel twin-screw extruder through a feeder, and add the mixture prepared in step (2) laterally (the third zone) of the parallel twin-screw extruder (with a total of eight zones) for melt extrusion and pelletizing. The process parameters include: the temperature of the first zone is 240 °C, the temperature of the second zone is 245 °C, the temperature of the third zone is 245 °C, the temperature of the fourth zone is 250 °C, the temperature of the fifth zone is 250 °C, the temperature of the sixth zone is 255 °C, the temperature of the seventh zone is 260 °C, the temperature of the eighth zone is 260 °C, the die head temperature is 255 °C, and the screw speed is 400 rpm.

[0089] The screw of the parallel twin-screw extruder has a single-thread thread shape; the ratio of the screw length L to the diameter D, L / D, is 35; there are 2 kneading block zones and 1 reverse-thread zone on the screw; in steps (1) and (2), the mixer is a high-speed mixer with a speed of 400 revolutions per minute.

[0090] Example 2 PET / PBT alloy and its preparation method

[0091] The PET / PBT alloy of this example is prepared from the following raw materials by weight:

[0092]

[0093]

[0094] The phosphite antioxidant is tetra (2,4-di-tert-butylphenyl)-4,4'-biphenyldiphosphite.

[0095] The preparation method of the PET / PBT alloy of this example includes the following steps:

[0096] (1) Place the PET resin and PBT resin at a temperature of 120 °C and dry for 2 hours, then cool; add the cooled PET resin, PBT resin, flame-retardant ACR resin, and phosphite antioxidant into a mixer for mixing;

[0097] (2) Add the GMA-g-EMA-g-SiO2, epoxy POSS, modified copper chromite black, and modified tin oxide into another high-speed mixer for mixing;

[0098] (3) Add the mixture prepared in step (1) into a parallel twin-screw extruder through a feeder, and add the mixture prepared in step (2) laterally (the third zone) of the parallel twin-screw extruder (with a total of eight zones) for melt extrusion and granulation. The process parameters include: the temperature of the first zone is 260 °C, the temperature of the second zone is 265 °C, the temperature of the third zone is 265 °C, the temperature of the fourth zone is 270 °C, the temperature of the fifth zone is 270 °C, the temperature of the sixth zone is 275 °C, the temperature of the seventh zone is 280 °C, the temperature of the eighth zone is 280 °C, the die head temperature is 275 °C, and the screw speed is 800 rpm.

[0099] The screw of the parallel twin-screw extruder has a single-thread shape; the ratio of the screw length L to the diameter D, L / D, is 55; there are 2 kneading block zones and 1 reverse-thread zone on the screw; in steps (1) and (2), the mixer is a high-speed mixer with a rotation speed of 1500 revolutions per minute.

[0100] Example 3 PET / PBT alloy and its preparation method

[0101] The PET / PBT alloy of this example is prepared from the following raw materials in parts by weight:

[0102]

[0103]

[0104] The phosphite antioxidant is tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenyldiphosphite.

[0105] The preparation method of the PET / PBT alloy of this example includes the following steps:

[0106] (1) Place the PET resin and PBT resin at a temperature of 113 °C and dry for 3.5 hours, then cool; add the cooled PET resin, PBT resin, flame-retardant ACR resin, and phosphite antioxidant into a mixer for mixing;

[0107] (2) Add the GMA-g-EMA-g-SiO2, epoxy POSS, modified copper chromite black, and modified tin oxide into another high-speed mixer for mixing;

[0108] (3) Add the mixture prepared in step (1) into a co-rotating twin-screw extruder through a feeder, and add the mixture prepared in step (2) laterally (the third zone) of the co-rotating twin-screw extruder (with a total of eight zones) for melt extrusion and pelletizing. The process parameters include: the temperature of the first zone is 245 °C, the temperature of the second zone is 250 °C, the temperature of the third zone is 250 °C, the temperature of the fourth zone is 255 °C, the temperature of the fifth zone is 255 °C, the temperature of the sixth zone is 260 °C, the temperature of the seventh zone is 265 °C, the temperature of the eighth zone is 265 °C, the die temperature is 260 °C, and the screw speed is 500 rpm.

[0109] The screw of the co-rotating twin-screw extruder has a single-thread screw shape; the ratio of the screw length L to the diameter D, L / D, is 40; there are 2 kneading block zones and 1 reverse-thread zone on the screw; in steps (1) and (2), the mixer is a high-speed mixer with a rotation speed of 500 revolutions per minute.

[0110] Example 4 PET / PBT alloy and its preparation method

[0111] The PET / PBT alloy of this example is prepared from the following raw materials by weight:

[0112]

[0113]

[0114] The phosphite antioxidant is tetra(2,4-di-tert-butylphenyl)-4,4'-biphenyldiphosphite.

[0115] The preparation method of the PET / PBT alloy of this example includes the following steps:

[0116] (1) Place the PET resin and PBT resin at a temperature of 117 °C and dry for 1.5 hours, then cool; add the cooled PET resin, PBT resin, flame-retardant ACR resin, and phosphite antioxidant into a mixer for mixing;

[0117] (2) Add the GMA-g-EMA-g-SiO2, epoxy POSS, modified copper chromite black, and modified tin oxide into another high-speed mixer for mixing;

[0118] (3) Feed the mixture prepared in step (1) into a parallel twin-screw extruder through a feeder, and add the mixture prepared in step (2) laterally (in the third zone) of the parallel twin-screw extruder (with a total of eight zones) for melt extrusion and granulation. The process parameters include: the temperature of the first zone is 255 °C, the second zone is 260 °C, the third zone is 260 °C, the fourth zone is 265 °C, the fifth zone is 265 °C, the sixth zone is 270 °C, the seventh zone is 275 °C, the eighth zone is 275 °C, the die head temperature is 270 °C, and the screw speed is 700 rpm.

[0119] The screw of the parallel twin-screw extruder has a single-thread shape; the ratio of the screw length L to the diameter D, L / D, is 50; there are 2 kneading block zones and 1 reverse-thread zone on the screw; in steps (1) and (2), the mixer is a high-speed mixer with a rotation speed of 1500 revolutions per minute.

[0120] Example 5 PET / PBT alloy and its preparation method

[0121] The PET / PBT alloy of this example is prepared from the following raw materials in parts by weight:

[0122]

[0123] The phosphite antioxidant is tetra(2,4-di-tert-butylphenyl)-4,4'-biphenyldiphosphite.

[0124] The preparation method of the PET / PBT alloy of this example includes the following steps:

[0125] (1) Place the PET resin and PBT resin at a temperature of 115 °C and dry for 2.5 hours, then cool; add the cooled PET resin, PBT resin, flame-retardant ACR resin, and phosphite antioxidant into a mixer for mixing;

[0126] (2) Add the GMA-g-EMA-g-SiO2, epoxy POSS, modified copper chromite black, and modified tin oxide into another high-speed mixer for mixing;

[0127] (3) Feed the mixture prepared in step (1) into a parallel twin-screw extruder through a feeder, and add the mixture prepared in step (2) laterally (in the third zone) of the parallel twin-screw extruder (with a total of eight zones) for melt extrusion and granulation. The process parameters include: the temperature of the first zone is 250 °C, the second zone is 255 °C, the third zone is 255 °C, the fourth zone is 260 °C, the fifth zone is 260 °C, the sixth zone is 265 °C, the seventh zone is 270 °C, the eighth zone is 270 °C, the die head temperature is 265 °C, and the screw speed is 600 rpm.

[0128] The screw of the parallel twin-screw extruder has a single-thread thread shape; the ratio of the screw length L to the diameter D, L / D, is 45; there are 2 kneading block zones and 1 reverse-thread zone on the screw; in steps (1) and (2), the mixer is a high-speed mixer with a rotation speed of 1000 revolutions per minute.

[0129] Example 6 PET / PBT alloy and its preparation method

[0130] The PET / PBT alloy of this example is prepared from the following raw materials in parts by weight:

[0131]

[0132] The phosphite antioxidant is tetra(2,4-di-tert-butylphenyl)-4,4'-biphenyldiphosphite.

[0133] The preparation method of the PET / PBT alloy of this example includes the following steps:

[0134] (1) Place the PET resin and PBT resin at a temperature of 115 °C and dry for 2.5 hours, then cool; add the cooled PET resin, PBT resin, flame-retardant ACR resin, and phosphite antioxidant to a mixer for mixing;

[0135] (2) Add the GMA-g-EMA-g-SiO2, epoxy POSS, modified copper chromite black, and modified tin oxide to another high-speed mixer for mixing;

[0136] (3) Add the mixture prepared in step (1) to a parallel twin-screw extruder through a feeder, and add the mixture prepared in step (2) laterally (the third zone) of the parallel twin-screw extruder (a total of eight zones) for melt extrusion and pelletizing. The process parameters include: the temperature of the first zone is 250 °C, the temperature of the second zone is 255 °C, the temperature of the third zone is 255 °C, the temperature of the fourth zone is 260 °C, the temperature of the fifth zone is 260 °C, the temperature of the sixth zone is 265 °C, the temperature of the seventh zone is 270 °C, the temperature of the eighth zone is 270 °C, the die head temperature is 265 °C, and the screw rotation speed is 600 rpm.

[0137] The screw of the parallel twin-screw extruder has a single-thread thread shape; the ratio of the screw length L to the diameter D, L / D, is 45; there are 2 kneading block zones and 1 reverse-thread zone on the screw; in steps (1) and (2), the mixer is a high-speed mixer with a rotation speed of 1000 revolutions per minute.

[0138] Example 7 PET / PBT alloy and its preparation method

[0139] The PET / PBT alloy of this example is prepared from the following raw materials in parts by weight:

[0140]

[0141] The phosphite antioxidant is tetra(2,4-di-tert-butylphenyl)-4,4'-biphenyldiphosphite.

[0142] The preparation method of the PET / PBT alloy in this example includes the following steps:

[0143] (1) Place the PET resin and PBT resin at a temperature of 115°C and dry for 2.5 hours, then cool; add the cooled PET resin, PBT resin, flame-retardant ACR resin and phosphite antioxidant to a blender for mixing;

[0144] (2) Add the GMA-g-EMA-g-SiO2, epoxy POSS, modified copper chromite black, and modified tin oxide to another high-speed blender for mixing;

[0145] (3) Add the mixture well-mixed in step (1) to a parallel twin-screw extruder through a feeder, and add the mixture well-mixed in step (2) laterally (in the third zone) of the parallel twin-screw extruder (a total of eight zones) for melt extrusion and pelletizing. The process parameters include: the temperature of the first zone is 250°C, the temperature of the second zone is 255°C, the temperature of the third zone is 255°C, the temperature of the fourth zone is 260°C, the temperature of the fifth zone is 260°C, the temperature of the sixth zone is 265°C, the temperature of the seventh zone is 270°C, the temperature of the eighth zone is 270°C, the die temperature is 265°C, and the screw speed is 600 rpm.

[0146] The screw of the parallel twin-screw extruder has a single-thread shape; the ratio of the screw length L to the diameter D, L / D, is 45; there are 2 kneading block zones and 1 reverse-thread zone on the screw; in steps (1) and (2), the blender is a high-speed blender with a rotation speed of 1000 revolutions per minute.

[0147] Comparative Example 1

[0148] The PET / PBT alloy in this comparative example is prepared from the following raw materials in parts by weight:

[0149]

[0150] The phosphite antioxidant is tetra(2,4-di-tert-butylphenyl)-4,4'-biphenyldiphosphite.

[0151] The preparation method of the PET / PBT alloy in this comparative example includes the following steps:

[0152] (1) After drying the PET resin and PBT resin at a temperature of 115°C for 2.5 hours, cool them; add the cooled PET resin, PBT resin, and phosphite antioxidant to a blender for mixing;

[0153] (2) Add the GMA-g-EMA-g-SiO2, epoxy POSS, modified copper chromite black, and modified tin oxide to another high-speed blender for mixing;

[0154] (3) Add the mixture prepared in step (1) to a co-rotating twin-screw extruder through a feeder, and add the mixture prepared in step (2) laterally (in the third zone) of the co-rotating twin-screw extruder (a total of eight zones) for melt extrusion and pelletizing. The process parameters include: the temperature of the first zone is 250°C, the temperature of the second zone is 255°C, the temperature of the third zone is 255°C, the temperature of the fourth zone is 260°C, the temperature of the fifth zone is 260°C, the temperature of the sixth zone is 265°C, the temperature of the seventh zone is 270°C, the temperature of the eighth zone is 270°C, the die temperature is 265°C, and the screw speed is 600 rpm.

[0155] The screw of the co-rotating twin-screw extruder has a single-thread shape; the ratio of the screw length L to the diameter D is 45; there are 2 kneading block zones and 1 reverse-thread zone on the screw; in steps (1) and (2), the blender is a high-speed blender with a speed of 1000 revolutions per minute.

[0156] Comparative Example 2

[0157] The PET / PBT alloy of this comparative example is prepared from the following raw materials in parts by weight:

[0158]

[0159] The phosphite antioxidant is bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite.

[0160] The preparation method of the PET / PBT alloy of this comparative example includes the following steps:

[0161] (1) After drying the PET resin and PBT resin at a temperature of 115°C for 2.5 hours, cool them; add the cooled PET resin, PBT resin, flame-retardant ACR resin, and phosphite antioxidant to a blender for mixing;

[0162] (2) Add the epoxy POSS, modified copper chromite black, and modified tin oxide to another high-speed blender for mixing;

[0163] (3) Feed the mixture prepared in step (1) into a parallel twin-screw extruder through a feeder, and add the mixture prepared in step (2) laterally (the third zone) of the parallel twin-screw extruder (with a total of eight zones) for melt extrusion and pelletizing. The process parameters include: the temperature of the first zone is 250 °C, the temperature of the second zone is 255 °C, the temperature of the third zone is 255 °C, the temperature of the fourth zone is 260 °C, the temperature of the fifth zone is 260 °C, the temperature of the sixth zone is 265 °C, the temperature of the seventh zone is 270 °C, the temperature of the eighth zone is 270 °C, the die temperature is 265 °C, and the screw speed is 600 rpm.

[0164] The screw of the parallel twin-screw extruder has a single-thread shape; the ratio of the screw length L to the diameter D, L / D, is 45; there are 2 kneading block zones and 1 reverse-thread zone on the screw; in steps (1) and (2), the mixer is a high-speed mixer with a speed of 1000 revolutions per minute.

[0165] Comparative Example 3

[0166] The PET / PBT alloy of this comparative example is prepared from the following raw materials in parts by weight:

[0167]

[0168] The phosphite antioxidant is tetra(2,4-di-tert-butylphenyl)-4,4'-biphenyldiphosphite.

[0169] The preparation method of the PET / PBT alloy of this comparative example includes the following steps:

[0170] (1) Place the PET resin and PBT resin at a temperature of 115 °C and dry for 2.5 hours, then cool; add the cooled PET resin, PBT resin, flame-retardant ACR resin, and phosphite antioxidant to a mixer for mixing;

[0171] (2) Add the GMA-g-EMA-g-SiO2, modified copper chromite black, and modified tin oxide to another high-speed mixer for mixing;

[0172] (3) Feed the mixture prepared in step (1) into a parallel twin-screw extruder through a feeder, and add the mixture prepared in step (2) laterally (the third zone) of the parallel twin-screw extruder (with a total of eight zones) for melt extrusion and pelletizing. The process parameters include: the temperature of the first zone is 250 °C, the temperature of the second zone is 255 °C, the temperature of the third zone is 255 °C, the temperature of the fourth zone is 260 °C, the temperature of the fifth zone is 260 °C, the temperature of the sixth zone is 265 °C, the temperature of the seventh zone is 270 °C, the temperature of the eighth zone is 270 °C, the die temperature is 265 °C, and the screw speed is 600 rpm.

[0173] The screw of the parallel twin-screw extruder has a single-thread shape; the ratio of the screw length L to the diameter D, L / D, is 45; there are 2 kneading block zones and 1 reverse-thread zone on the screw; in steps (1) and (2), the mixer is a high-speed mixer with a rotational speed of 1000 revolutions per minute.

[0174] Comparative Example 4

[0175] The PET / PBT alloy of this comparative example is prepared from the following raw materials in parts by weight:

[0176]

[0177] The phosphite antioxidant is tetra(2,4-di-tert-butylphenyl)-4,4'-biphenyldiphosphite.

[0178] The preparation method of the PET / PBT alloy of this comparative example includes the following steps:

[0179] (1) Place the PET resin and PBT resin at a temperature of 115°C and dry for 2.5 hours, then cool; add the cooled PET resin, PBT resin, flame-retardant ACR resin, and phosphite antioxidant to a mixer for mixing;

[0180] (2) Add the GMA-g-EMA-g-SiO2, epoxy POSS, and modified tin oxide to another high-speed mixer for mixing;

[0181] (3) Add the mixture well-mixed in step (1) to a parallel twin-screw extruder through a feeder, and add the mixture well-mixed in step (2) laterally (in the third zone) of the parallel twin-screw extruder (with a total of eight zones) for melt extrusion and pelletization. The process parameters include: the temperature of the first zone is 250°C, the temperature of the second zone is 255°C, the temperature of the third zone is 255°C, the temperature of the fourth zone is 260°C, the temperature of the fifth zone is 260°C, the temperature of the sixth zone is 265°C, the temperature of the seventh zone is 270°C, the temperature of the eighth zone is 270°C, the die head temperature is 265°C, and the screw rotational speed is 600 rpm.

[0182] The screw of the parallel twin-screw extruder has a single-thread shape; the ratio of the screw length L to the diameter D, L / D, is 45; there are 2 kneading block zones and 1 reverse-thread zone on the screw; in steps (1) and (2), the mixer is a high-speed mixer with a rotational speed of 1000 revolutions per minute.

[0183] Comparative Example 5

[0184] The PET / PBT alloy of this comparative example is prepared from the following raw materials in parts by weight:

[0185]

[0186] The phosphite antioxidant is tetra(2,4-di-tert-butylphenyl)-4,4'-biphenyldiphosphite.

[0187] The preparation method of the PET / PBT alloy in this comparative example includes the following steps:

[0188] (1) After drying the PET resin and PBT resin at a temperature of 115 °C for 2.5 hours, they are cooled; the cooled PET resin, PBT resin, flame-retardant ACR resin and phosphite antioxidant are added to a mixer for mixing;

[0189] (2) The GMA-g-EMA-g-SiO2, epoxy POSS, and modified copper chromite black are added to another high-speed mixer for mixing;

[0190] (3) The mixture well-mixed in step (1) is added to a twin-screw extruder through a feeder, and the mixture well-mixed in step (2) is added laterally (in the third zone) to the twin-screw extruder (with a total of eight zones) for melt extrusion and pelletizing. The process parameters include: the temperature of the first zone is 250 °C, the temperature of the second zone is 255 °C, the temperature of the third zone is 255 °C, the temperature of the fourth zone is 260 °C, the temperature of the fifth zone is 260 °C, the temperature of the sixth zone is 265 °C, the temperature of the seventh zone is 270 °C, the temperature of the eighth zone is 270 °C, the die temperature is 265 °C, and the screw speed is 600 rpm.

[0191] The screw of the twin-screw extruder has a single-thread screw shape; the ratio of the screw length L to the diameter D, L / D, is 45; there are 2 kneading block zones and 1 reverse-thread zone on the screw; in steps (1) and (2), the mixer is a high-speed mixer with a rotation speed of 1000 revolutions per minute.

[0192] Comparative Example 6

[0193] The PET / PBT alloy in this comparative example is prepared from the following raw materials in parts by weight:

[0194]

[0195] The preparation method of the PET / PBT alloy in this comparative example includes the following steps:

[0196] (1) After drying the PET resin and PBT resin at a temperature of 115 °C for 2.5 hours, they are cooled; the cooled PET resin, PBT resin, flame-retardant ACR resin are added to a mixer for mixing;

[0197] (2) The GMA-g-EMA-g-SiO2, epoxy POSS, modified copper chromite black, and modified tin oxide are added to another high-speed mixer for mixing;

[0198] (3) Feed the mixture well - mixed in step (1) into a parallel twin - screw extruder through a feeder, and add the mixture well - mixed in step (2) laterally (the third zone) of the parallel twin - screw extruder (with a total of eight zones) for melt extrusion and pelletizing. The process parameters include: the temperature of the first zone is 250 °C, the temperature of the second zone is 255 °C, the temperature of the third zone is 255 °C, the temperature of the fourth zone is 260 °C, the temperature of the fifth zone is 260 °C, the temperature of the sixth zone is 265 °C, the temperature of the seventh zone is 270 °C, the temperature of the eighth zone is 270 °C, the die head temperature is 265 °C, and the screw speed is 600 rpm.

[0199] The screw of the parallel twin - screw extruder has a single - thread shape; the ratio of the screw length L to the diameter D, L / D, is 45; there are 2 kneading block zones and 1 reverse - thread zone on the screw; in steps (1) and (2), the mixer is a high - speed mixer with a rotation speed of 1000 revolutions per minute.

[0200] The following is a list of the raw material compositions of Examples 1 - 7 and Comparative Examples 1 - 6.

[0201] Table 1 List of raw material compositions of Examples 1 - 7 and Comparative Examples 1 - 6

[0202]

[0203] In Examples 1 - 7, PET / PBT alloys were prepared by adjusting the addition amounts of PET resin, PBT resin, flame - retardant ACR resin, GMA - g - EMA - g - SiO2, epoxy - based POSS, modified copper chromite black, modified tin oxide, and phosphite antioxidant. In Comparative Example 1, a PET / PBT alloy was prepared without adding flame - retardant ACR resin. In Comparative Example 2, a PET / PBT alloy was prepared without adding GMA - g - EMA - g - SiO2. In Comparative Example 3, a PET / PBT alloy was prepared without adding epoxy - based POSS. In Comparative Example 4, a PET / PBT alloy was prepared without adding modified copper chromite black. In Comparative Example 5, a PET / PBT alloy was prepared without adding modified tin oxide. In Comparative Example 6, a PET / PBT alloy was prepared without adding phosphite antioxidant.

[0204] Perform the following performance tests on the PET / PBT alloys prepared in the above examples and comparative examples:

[0205] Tensile strength: Test according to the GB / T 1040 - 2006 standard, and the tensile rate is 50 mm / min.

[0206] Notched impact strength: Test according to the GB / T 1843 - 2008 standard.

[0207] Flame retardant performance: According to GB / T 2406.2-2009 standard test, the limiting oxygen index of the sample is determined by an oxygen index meter, and the sample size is 150mm×6.5mm×3mm.

[0208] Dielectric constant: Tested according to GB / T 5597-1999 standard, test frequency 5GHz.

[0209] Laser direct forming: Adopt the adhesion test of metal coating on the surface of plastic parts (or called hundred-grid test), test according to ASTMD3359 standard, as follows: at room temperature 23±2℃, relative humidity 50±5%, use a sharp blade (blade angle is 15°~30°) to draw 10×10 1mm×1mm small grids on the surface of the test sample, and each line is deep to the bottom layer of the coating; brush the test area clean; use 3M 600 tape to firmly stick to the small grid to be tested, and use an eraser to wipe the tape vigorously to increase the contact area and strength between the tape and the tested area; grab one end of the tape with your hand, and quickly tear off the transparent tape at a 60° angle in the vertical direction, and perform the same test twice at the same position. Result determination: Adhesion is qualified when it is ≥4B; 5B-the edge of the line is smooth, and there is no paint falling off at the edge and intersection of the line; 4B-small pieces of paint fall off at the intersection of the line, and the total falling area is less than 5%; 3B-small pieces of paint fall off at the edge and intersection of the line, and the total falling area is between 5% and 15%; 2B-large pieces of paint fall off at the edge and intersection of the line, and the total falling area is between 15% and 35%; 1B-large pieces of paint fall off at the edge and intersection of the line, and the total falling area is between 35% and 65%; 0B-large pieces of paint fall off at the edge and intersection of the line, and the total falling area is greater than 65%.

[0210] The performance test results are shown in Table 2.

[0211] Table 2 Properties of PET / PBT alloys of Examples 1-7 and Comparative Examples 1-6

[0212]

[0213]

[0214] From Table 2 we can see that:

[0215] With the increase in the addition amounts of PBT resin and GMA-g-EMA-g-SiO2, the tensile strength and impact strength of the PET / PBT alloy gradually increase. This is because: the crystal nucleation rate and growth rate of PBT resin are both higher than those of PET resin, that is, the crystallinity of PBT resin is much higher than that of PET resin, so the tensile strength of PBT resin is higher than that of PET resin. At the same time, the methyl acrylate structural unit of GMA-g-EMA-g-SiO2 has good compatibility with the PET / PBT alloy, and the epoxy group can react with the terminal hydroxyl groups of PET resin and PBT resin, improving the interfacial adhesion and compatibility of PET resin and PBT resin. Moreover, both the ethylene structural unit and the methyl acrylate structural unit of GMA-g-EMA-g-SiO2 have good toughening effects.

[0216] With the increase in the addition amounts of flame-retardant ACR resin, GMA-g-EMA-g-SiO2, and epoxy POSS, the flame retardancy of the PET / PBT alloy gradually increases. This is because: (1) For the flame-retardant ACR resin, using the synergistic flame retardancy of P-Si and the toughening structure characteristics of ACR, choosing siloxane as the core layer, phosphorus-containing acrylate monomer as the shell layer, and silane coupling agent (γ-methacryloxypropyltrimethoxysilane) as the cross-linking agent, it can improve the impact performance of the material by inhibiting the generation and growth of microcracks. At the same time, the flame-retardant ACR resin can play a role in flame-retarding the PET / PBT alloy in the gas phase and condensed phase; (2) GMA-g-EMA-g-SiO2 is prepared by grafting ethylene-methyl acrylate copolymer (GMA-g-EMA) onto the surface of nano-SiO2 to obtain a nano-SiO2 with amphiphilic properties. The methyl acrylate structural unit of this GMA-g-EMA-g-SiO2 has good compatibility with the PET / PBT alloy, and the epoxy group can react with the terminal hydroxyl groups of PET resin and PBT resin, improving the interfacial adhesion and compatibility of PET resin and PBT resin. At the same time, GMA-g-EMA-g-SiO2 can form a continuous silicon-containing carbon layer at the interface, inhibiting the decomposition of PET resin and PBT resin, and playing a role in synergistic flame retardancy; (3) As a typical organosilicon-based flame retardant, epoxy POSS can effectively flame-retard the PET / PBT alloy in its compound flame retardant system.

[0217] With the increase in the addition amount of epoxy-POSS, the dielectric constant of the PET / PBT alloy gradually decreases. This is because: Epoxy-POSS has low dielectric properties. Under the condition of a test frequency of 5 GHz, its dielectric constant is only 2.1 - 2.4. This property mainly stems from the unique cage-like three-dimensional structure of POSS. The center of this structure is an inorganic core composed of alternating silicon-oxygen (Si-O) connections, and the silicon atoms at the eight vertices are respectively connected to organic substituents (R groups). This cage-like structure creates a large space inside the molecule, preventing the molecules from packing tightly, thereby reducing the degree of molecular polarization. When an electric field acts, the molecules are difficult to be polarized, and the dielectric constant decreases accordingly. The Si-O bond has a relatively high bond energy of 445.2 kJ / mol. In contrast, the C-C bond energy is 350.7 kJ / mol, and the C-O bond energy is 359.1 kJ / mol. The Si-O bond is more difficult to break. Therefore, in an electric field, the vibration and rotation of the Si-O bond are less affected, and the response to the electric field weakens, which further reduces the dielectric constant.

[0218] With the increase in the addition amounts of modified copper chromite black and modified tin oxide, the laser forming performance of the PET / PBT alloy is both 5B. This is because: (1) The nano-dispersion mechanism induced by chemical bonding: The epoxy groups of the modified fillers react with the terminal hydroxyl groups of PC to form a covalent cross-linked network, breaking through the limitation of the weak interfacial interaction in traditional physical blending, enabling copper chromite black / tin oxide to achieve nano-scale uniform dispersion (particle size < 50 nm) in the matrix and eliminating the heterogeneity of laser absorption; (2) The laser-catalytic dual-response characteristics of copper chromite black: The d-d electron transition characteristics of its spinel crystal structure precisely match the 1064 nm laser wavelength, and through the localized surface plasmon resonance effect, the photon energy is efficiently converted into heat energy, inducing the formation of micron-scale activation pits on the PC matrix; The simultaneously exposed CuCr2O4(111) crystal plane can serve as a highly active catalytic site, reducing the reduction activation energy of Cu 2+ in the electroless plating solution from 0.85 eV to 0.28 eV, driving the preferential nucleation and epitaxial growth of metal ions on the laser track; (3) The construction of the pre-conductive network of tin oxide: SnO2 forms a continuous electron transport channel (carrier density > 10 18 cm -3 ) through the modified interface, forming an ohmic contact interface with a gradient energy level match with the deposited metal during the electroless plating process, reducing the metal / matrix interface resistance to the 10 -4 Ω·cm 2 level, which is 3 orders of magnitude lower than that of the traditional system.

[0219] In summary, by adjusting the addition amounts of PET resin, PBT resin, flame-retardant ACR resin, GMA-g-EMA-g-SiO2, epoxy POSS, modified copper chromite black, modified tin oxide, and phosphite antioxidant, and with the synergistic cooperation of various additives, the PET / PBT alloy of the present invention with excellent mechanical properties, flame-retardant properties, low dielectric properties, and laser forming properties can be obtained.

[0220] Compared with Example 7, in Comparative Example 1, a PET / PBT alloy was prepared without adding flame-retardant ACR resin. Since the flame-retardant ACR resin utilizes the synergistic flame-retardant effect of P-Si and the toughening structure characteristics of ACR, with siloxane as the core layer, phosphorus-containing acrylate monomer as the shell layer, and silane coupling agent (γ-methacryloxypropyltrimethoxysilane) as the cross-linking agent, it can improve the impact performance of the material by inhibiting the generation and growth of microcracks. At the same time, the flame-retardant ACR resin can play a role in flame-retarding the PET / PBT alloy in the gas phase and condensed phase. Therefore, the notched impact strength and flame-retardant properties of Comparative Example 1 are lower than those of Example 7.

[0221] Compared with Example 7, in Comparative Example 2, a PET / PBT alloy was prepared without adding GMA-g-EMA-g-SiO2. Since GMA-g-EMA-g-SiO2 is prepared by grafting ethylene-methyl acrylate copolymer grafted glycidyl methacrylate (GMA-g-EMA) onto the surface of nano-SiO2 to obtain a nano-SiO2 with amphiphilic properties. The methyl acrylate structural unit of GMA-g-EMA-g-SiO2 has good compatibility with the PET / PBT alloy, and the epoxy group can react with the terminal hydroxyl groups of PET resin and PBT resin to improve the interfacial adhesion and compatibility of PET resin and PBT resin. At the same time, GMA-g-EMA-g-SiO2 can form a continuous silicon-containing carbon layer at the interface to inhibit the decomposition of PET resin and PBT resin, playing a synergistic flame-retardant role. Therefore, the tensile strength, notched impact strength, and flame-retardant properties of Comparative Example 2 are lower than those of Example 7.

[0222] Comparing with Example 7, Comparative Example 3 is to prepare a PET / PBT alloy without adding epoxy POSS. As a typical silicone-based flame retardant, the epoxy POSS can play an effective flame retardant role in the PET / PBT alloy through its compound flame retardant system. The end groups of epoxy POSS contain epoxy groups, and these epoxy groups can react with the terminal hydroxyl groups of PET resin and PBT resin, thereby improving the dispersion and compatibility of epoxy POSS in PET resin and PBT resin materials, and ultimately enhancing the flame retardant performance of the PET / PBT alloy. Epoxy POSS has low dielectric characteristics. Under the condition that the test frequency is 5 GHz, its dielectric constant is only 2.1 - 2.4. This characteristic mainly stems from the unique cage-like three-dimensional structure of POSS. The center of this structure is an inorganic core composed of alternating silicon-oxygen (Si-O) connections, and the silicon atoms at the eight vertices are respectively connected with organic substituent groups (R groups). This cage structure results in a relatively large space inside the molecule, making it impossible for the molecules to be closely packed, thereby reducing the degree of molecular polarization. When an electric field acts, the molecules are difficult to be polarized, and the dielectric constant decreases accordingly. The Si-O bond has a relatively high bond energy of 445.2 kJ / mol. In contrast, the bond energy of the C-C bond is 350.7 kJ / mol, and the bond energy of the C-O bond is 359.1 kJ / mol. The Si-O bond is more difficult to be broken. Therefore, in an electric field, the vibration and rotation of the Si-O bond are less affected, and the response to the electric field weakens, which further reduces the dielectric constant. Therefore, the dielectric constant of Comparative Example 3 is higher than that of Example 7.

[0223] Comparing with Example 7, Comparative Example 4 is to prepare a PET / PBT alloy without adding modified copper chromite black. Due to the laser-catalytic dual-response characteristics of copper chromite black: the d-d electron transition characteristics of its spinel crystal structure precisely match the 1064 nm laser wavelength, and the photon energy is efficiently converted into heat energy through the local surface plasmon resonance effect, inducing the formation of micron-scale activation pits on the PC matrix; simultaneously, the exposed CuCr2O4(111) crystal plane can serve as a highly active catalytic site, reducing the reduction activation energy of Cu 2+ from 0.85 eV to 0.28 eV, driving the preferential nucleation and epitaxial growth of metal ions along the laser track. Therefore, Comparative Example 4 does not have laser forming performance.

[0224] Comparing with Example 7, Comparative Example 5 is to prepare a PET / PBT alloy without adding modified tin oxide. Since SnO2 forms a continuous electron transport channel (carrier density > 10 18 cm -3 ) through the modified interface, and forms an Ohmic contact interface with a gradient energy level matching with the deposited metal during the electroless plating process, reducing the metal / substrate interface resistance to 10 -4 Ω·cm 2The level is reduced by three orders of magnitude compared with the traditional system. Therefore, the laser forming performance of Comparative Example 5 is lower than that of Example 7.

[0225] Compared with Example 7, in Comparative Example 6, a PET / PBT alloy was prepared without adding phosphite antioxidants. Since tetra(2,4-di-tert-butylphenyl)-4,4'-biphenyldiphosphite is an efficient phosphite antioxidant, it plays a synergistic antioxidant role through multiple mechanisms in the blending process of PET / PBT alloys. Among them, the phosphite group in the antioxidant molecule can react preferentially with the hydroperoxides (ROOH) generated during processing, converting them into stable alcohols (ROH) and blocking the propagation of free radical chain oxidation reactions; the steric hindrance effect of the biphenyl rigid skeleton and the four 2,4-di-tert-butylphenyl groups endows it with excellent thermal stability (decomposition temperature > 350 °C), and it can still maintain its structural integrity during the high-temperature melt processing of PET / PBT alloys; at the same time, the phosphorus atom in the molecule captures metal ion impurities (such as residual catalysts) through coordination, inhibiting metal-catalyzed oxidation reactions. Therefore, the tensile strength and notched impact strength of Comparative Example 6 are lower than those of Example 7.

[0226] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0227] The above-described embodiments merely represent several implementation manners of the present invention. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A PET / PBT alloy, characterized in that, It is prepared from the following raw materials in parts by weight: 70 - 90 parts of PET resin, 10 - 30 parts of PBT resin, The total weight parts of the PET resin and the PBT resin is 100 parts, The GMA-g-EMA-g-SiO2 is ethylene-methyl acrylate copolymer double graft glycidyl methacrylate and silica.

2. The PET / PBT alloy according to claim 1, characterized in that, It is prepared from the following raw materials in parts by weight: 75 - 85 parts of PET resin, 15 - 25 parts of PBT resin, The total weight parts of the PET resin and the PBT resin is 100 parts, 3. The PET / PBT alloy according to claim 1 or 2, characterized in that, The intrinsic viscosity of the PET resin is 0.65 dL / g - 0.75 dL / g; and / or, the intrinsic viscosity of the PBT resin is 0.8 dL / g - 0.9 dL / g.

4. The PET / PBT alloy according to claim 1 or 2, characterized in that, The modified copper chromite black is obtained by organically modifying copper chromite black with γ-(2,3-epoxypropoxy)propyltrimethoxysilane; and / or, the modified tin oxide is obtained by organically modifying tin oxide with γ-(2,3-epoxypropoxy)propyltrimethoxysilane; and / or, the phosphite antioxidant is tetra(2,4-di-tert-butylphenyl)-4,4'-biphenyldiphosphite.

5. The PET / PBT alloy according to claim 1 or 2, characterized in that, The preparation method of the flame-retardant ACR resin comprises the following steps: (1) Mix 90 g - 96 g of octamethylcyclotetrasiloxane, 7 g - 11 g of γ-methacryloxypropyltrimethoxysilane, 2 g - 3 g of dodecylbenzenesulfonic acid and 150 mL - 200 mL of deionized water, carry out pre-emulsification at a stirring speed of 300 rpm - 500 rpm for 0.3 h - 0.7 h, then add 0.9 g - 1.3 g of dodecylbenzenesulfonic acid and 400 mL - 600 mL of deionized water, heat in a constant temperature water bath to 75°C - 95°C, and maintain the rotation speed at 150 rpm - 250 rpm. After reacting for 2 h - 4 h, cool down to obtain a polysiloxane core emulsion; adjust the pH value of the polysiloxane core emulsion to 7.8 - 8.2 with a 2wt% - 4wt% sodium hydroxide solution. After adjustment, add 1.7 g - 2.7 g of potassium persulfate dropwise to the polysiloxane core emulsion; (2) Mix 80 g - 90 g of diethyl methylphosphonate acrylate, 140 g - 180 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide graft acrylate monomer, 2 g - 3 g of sodium dodecyl sulfate and 300 mL - 500 mL of deionized water, carry out pre-emulsification at a stirring speed of 300 rpm - 500 rpm for 0.3 h - 0.7 h, and then dropwise add it to the polysiloxane core emulsion obtained in the above step (1) whose temperature has been raised to 75°C - 85°C. After dropping, add 1.1 g - 1.5 g of potassium persulfate as a supplement, react for 2 h - 4 h, then cool down, demulsify, and filter to obtain.

6. The PET / PBT alloy according to claim 1 or 2, characterized in that, The preparation method of the GMA-g-EMA-g-SiO2 comprises the following steps: adding 100 g of amino group-containing SiO2 into 500 mL to 700 mL of N,N-dimethylformamide, and performing ultrasonic treatment for 10 min to 20 min to obtain a uniform dispersion; dissolving 60 g to 80 g of GMA-g-EMA in 200 mL to 400 mL of N,N-dimethylformamide to obtain an N,N-dimethylformamide solution of GMA-g-EMA; stirring the dispersion at a rotation speed of 300 rpm to 500 rpm, and slowly dropping the N,N-dimethylformamide solution of GMA-g-EMA at 85°C to 95°C, and keeping the reaction conditions unchanged for condensation reflux for 10 h to 14 h; centrifuging the reacted solution, washing with absolute ethanol, and drying at 55°C to 65°C for 10 h to 14 h to obtain GMA-g-EMA-g-SiO2.

7. A method for preparing a PET / PBT alloy according to any one of claims 1-6, characterized in that, Comprising the following steps: (1) Placing the PET resin and PBT resin at a temperature of 110°C to 120°C and drying for 2 hours to 4 hours, and then cooling; adding the cooled PET resin, PBT resin, flame retardant ACR resin and phosphite antioxidant into a blender for mixing; (2) Adding the GMA-g-EMA-g-SiO2, epoxy POSS, modified copper chromite black and modified tin oxide into another high-speed blender for mixing; (3) Adding the mixture well-mixed in step (1) into a parallel twin-screw extruder through a feeder, and laterally adding the mixture well-mixed in step (2) into the parallel twin-screw extruder for melt extrusion and pelletizing. The process parameters include: the temperature of the first zone is 240°C to 260°C, the temperature of the second zone is 245°C to 265°C, the temperature of the third zone is 245°C to 265°C, the temperature of the fourth zone is 250°C to 270°C, the temperature of the fifth zone is 250°C to 270°C, the temperature of the sixth zone is 255°C to 275°C, the temperature of the seventh zone is 260°C to 280°C, the temperature of the eighth zone is 260°C to 280°C, the die head temperature is 255°C to 275°C, and the screw rotation speed is 400 rpm to 800 rpm.

8. The preparation method according to claim 7, characterized in that, Comprising the following steps: (1) Placing the PET resin and PBT resin at a temperature of 113°C to 117°C and drying for 1.5 hours to 3.5 hours, and then cooling; adding the cooled PET resin, PBT resin, flame retardant ACR resin and phosphite antioxidant into a blender for mixing; (2) Adding the GMA-g-EMA-g-SiO2, epoxy POSS, modified copper chromite black and modified tin oxide into another high-speed blender for mixing; (3) Add the mixture prepared in step (1) into a parallel twin-screw extruder through a feeder, and laterally add the mixture prepared in step (2) into the parallel twin-screw extruder for melt extrusion and granulation. The process parameters include: the temperature of zone 1 is 245 °C to 255 °C, the temperature of zone 2 is 250 °C to 260 °C, the temperature of zone 3 is 250 °C to 260 °C, the temperature of zone 4 is 255 °C to 265 °C, the temperature of zone 5 is 255 °C to 265 °C, the temperature of zone 6 is 260 °C to 270 °C, the temperature of zone 7 is 265 °C to 275 °C, the temperature of zone 8 is 265 °C to 275 °C, the die head temperature is 260 °C to 270 °C, and the screw speed is 500 rpm to 700 rpm.

9. The preparation method according to claim 7 or 8, characterized in that, The screw of the parallel twin-screw extruder has a single-thread shape; and / or, the ratio of the screw length L to the diameter D of the parallel twin-screw extruder, L / D, is 35 to 55; and / or, there is more than 1 engagement block zone and more than 1 reverse-thread zone on the screw of the parallel twin-screw extruder; in step (1) and / or step (2), the mixer is a high-speed mixer with a speed of 500 revolutions per minute to 1500 revolutions per minute.

10. The preparation method according to claim 9, characterized in that, The ratio of the screw length L to the diameter D of the parallel twin-screw extruder, L / D, is 40 to 50; and / or, there are 2 engagement block zones and 1 reverse-thread zone on the screw of the parallel twin-screw extruder.

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