Mineral reinforced PC / PBT alloy material with dimensional stability and warping resistance and preparation method of mineral reinforced PC / PBT alloy material

Abstract

The invention discloses a warp-resistant mineral reinforced PC / PBT alloy material with dimensional stability and a preparation method thereof, and relates to the technical field of polymer composite materials. The preparation method comprises the following steps: weighing polycarbonate, polybutylene terephthalate, ureido pyrimidone-polydimethylsiloxane, epoxy polyhedral oligomeric silsesquioxane, polyimide coated halloysite nanotubes, magnesium-aluminum hydrotalcite, perfluoroalkyl modified boron nitride nanosheets, liquid crystal polymer microfibers, modified PVA (Polyvinyl Alcohol) fibers and a silane coupling agent KH550 according to a ratio; the preparation method comprises the following steps: pre-mixing polycarbodiimide and a composite antioxidant to obtain a mixture, mixing, adding into a double-screw extruder, extruding and granulating, drying, carrying out injection molding, and standing at constant temperature and constant humidity to obtain the composite material. The invention has the significance of providing the PBT / PC alloy material with dimensional stability, warping resistance, low shrinkage rate, low hygroscopicity, creep resistance, impact resistance, arc resistance and chemical corrosion resistance for consumer-grade and industrial-grade underwater plastic parts.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer composite materials, and particularly to a dimensionally stable and warpage-resistant mineral-reinforced PC / PBT alloy material and a preparation method thereof. Background Art

[0002] In underwater environments such as rivers, lakes, reservoirs, and household swimming pools, the outer shells of electromechanical equipment, the housings of detection sensors, and diving components are constantly faced with complex and variable mechanical, chemical, and hygrothermal challenges. Existing underwater engineering plastics are mostly based on a single PC / PBT alloy material system of polycarbonate (PC) or polybutylene terephthalate (PBT), or are modified by simple blending, but their performance is difficult to meet the multiple stringent requirements of underwater scenarios for materials. To improve the above defects, prior art attempts to introduce mineral fillers (such as talc powder, glass fiber) or dynamic crosslinking agents for modification. However, the addition of a high proportion of mineral fillers can improve rigidity but causes a sharp drop in the toughness of the material, and uneven dispersion of the fillers leads to local stress concentration, which is prone to brittle fracture under complex deformation. In addition, traditional dynamic crosslinking networks are prone to hydrolysis failure in a long-term hygrothermal environment, and the dynamic self-adaptive ability decays with the extension of service time, unable to maintain the dimensional stability of the material. Surface coating modification (such as spraying fluorocarbon PC / PBT alloy materials) can temporarily improve hydrophobicity, but the bonding force between the coating and the alloy material matrix is weak, and it is prone to peeling under mechanical friction or temperature alternation, and it cannot resist medium penetration caused by underwater pressure fluctuations, making it difficult to achieve endogenous optimization of the bulk properties.

[0003] The current market demand for underwater engineering plastics has shifted from single-performance improvement to multi-dimensional collaborative strengthening. Especially for consumer-grade small devices, there is an urgent need for a low-cost material with high rigidity, warpage resistance, creep resistance, chemical corrosion resistance, and long-term dimensional stability. However, prior art is mostly limited to single-function optimization or exogenous repair, lacking a systematic solution to the multi-environment coupling effect (long-term water immersion, temperature alternation, mechanical load, chemical corrosion, arc shock), resulting in performance imbalance of materials in complex underwater environments, such as interface defects and performance imbalance, insufficient dynamic environmental adaptability, difficulty in coexistence of impact resistance and arc resistance, or mutual restriction between low moisture absorption and creep resistance. Therefore, there is an urgent need to develop a long-term reliable PC / PBT alloy material for various complex underwater environments. Summary of the Invention

[0004] The purpose of the present invention is to provide a dimensionally stable and warpage-resistant mineral-reinforced PC / PBT alloy material and a preparation method thereof to solve the problems raised in the background art.

[0005] To achieve the above purpose, the present invention provides the following technical solutions: A dimensionally stable and warpage-resistant mineral-reinforced PC / PBT alloy material, comprising the following raw material components by weight parts: Polycarbonate (PC) 55 - 65 parts; Polybutylene terephthalate (PBT) 35 - 45 parts; Ureidopyrimidinone-polydimethylsiloxane 6 - 9 parts; Epoxy-functionalized cage-like silsesquioxane 2 - 3 parts; Polyimide-coated halloysite nanotubes 6 - 10 parts; Magnesium aluminum hydrotalcite 3 - 5 parts; Perfluoroalkyl-modified boron nitride nanosheets 4 - 6 parts; Liquid crystal polymer microfibrils 2 - 4 parts; Modified PVA fibers 1.2 - 1.8 parts; Silane coupling agent KH550 0.2 - 0.3 parts; Polycarbodiimide 0.6 - 1 part; Compound antioxidant 0.3 - 0.5 part; Furthermore, the total weight parts of polycarbonate and polybutylene terephthalate are 100 parts; Furthermore, the weight ratio of ureidopyrimidinone-polydimethylsiloxane to epoxy-functionalized cage-like silsesquioxane is 3:1; Furthermore, the weight ratio of polyimide-coated halloysite nanotubes to magnesium aluminum hydrotalcite is 2:1; Furthermore, the compound antioxidant is a compound of antioxidant 1010 and antioxidant 168 in a ratio of 1:1.

[0006] Furthermore, the preparation steps of the ureidopyrimidinone-polydimethylsiloxane are as follows: A1. Under nitrogen protection, mix 2-amino-4-hydroxy-6-methylpyrimidine with hexamethylene diisocyanate, reflux and react at 110 - 130 °C for 12 - 14 h, add petroleum ether, filter by suction, and dry to obtain an isocyanate-terminated intermediate; The dosage ratio of 2-amino-4-hydroxy-6-methylpyrimidine to hexamethylene diisocyanate is 10 g:(64 - 72) g; A2. Dissolve amino-terminated polydimethylsiloxane in toluene, preheat at 80 - 90 °C for 15 min, add the isocyanate-terminated intermediate, and react under stirring at a speed of 500 - 800 r / min for 12 - 14 h. Cool the reaction solution to room temperature, precipitate in n-hexane, centrifuge, wash, and vacuum dry at 60 - 65 °C for 24 h to obtain ureidopyrimidinone-polydimethylsiloxane.

[0007] The dosage ratio of the amino-terminated polydimethylsiloxane, toluene, isocyanate-terminated intermediate and n-hexane is 100 g: 300 mL: (117 - 123) g: 1500 mL.

[0008] It should be noted that the ureidopyrimidinone-polydimethylsiloxane acts as a dynamic crosslinking agent and realizes multi-scale synergistic reinforcement in the PC / PBT alloy material through its unique dual functions. The ureidopyrimidinone unit forms a reversible physical crosslinking network through quadruple hydrogen bonds, endowing the material with self-healing ability and creep resistance. When external stress induces microcracks, the hydrogen bonds dissociate and recombine dynamically, effectively dissipating energy and inhibiting permanent deformation. The polydimethylsiloxane chain segments, relying on their low surface energy characteristics, form a hydrophobic barrier on the material surface and phase interface, significantly reducing the adsorption of water molecules and oily media, thereby improving chemical corrosion resistance and dimensional stability.

[0009] It should be noted again that the quadruple hydrogen bonds of ureidopyrimidinone form a dynamic hydrogen bond network with the polar groups (ester groups, hydroxyl groups) of the PC / PBT alloy material, enhancing the interface energy dissipation ability. At the same time, the dynamic hydrogen bond network of ureidopyrimidinone and the rigid tubular structure of the halloysite nanotubes wrapped with polyimide form a soft-hard interpenetrating framework, balancing the rigidity and toughness of the PC / PBT alloy material. The flexible chain segments of polydimethylsiloxane fill the intertubular voids of the halloysite nanotubes, blocking the water molecule penetration path, keeping the material with a low moisture absorption rate, and optimizing the performance of the PC / PBT alloy material in the underwater environment.

[0010] Furthermore, the preparation steps of the polyimide-wrapped halloysite nanotubes are as follows: B1. Mix the halloysite nanotubes with hydrochloric acid solution, ultrasonically disperse for 30 - 45 min, stir at 60 °C for 2 - 3 h, centrifuge, wash until neutral, and dry at 80 - 90 °C for 12 - 14 h to obtain the pickled halloysite nanotubes; The concentration of the hydrochloric acid solution is (2.4 - 3) mol / L; The dosage ratio of the halloysite nanotubes to hydrochloric acid is (80 - 120) g: 500 mL; B2. Dissolve pyromellitic dianhydride and 4,4'-diaminodiphenyl ether in N-methylpyrrolidone in an ice-water bath at 0 - 5 °C, add the pickled halloysite nanotubes, ultrasonically disperse for 1 h, and raise the temperature to 45 - 49 °C to react for 4 h to form a crude slurry of halloysite nanotubes coated with polyamic acid; The dosage ratio of the pickled halloysite nanotubes, pyromellitic dianhydride, 4,4'-diaminodiphenyl ether, and N-methylpyrrolidone is 100 g: (35 - 45) g: (34 - 36) g: 1000 mL; It should be noted that controlling the polycondensation temperature below 50 °C can avoid premature imidization of polyamic acid.

[0011] B3. Coarsely coat the halloysite nanotubes coated with polyamic acid evenly in a mold, heat it at a gradient of 60 °C / h to 300 °C, keep it warm for 2 h, cool it and demold it, mechanically crush it, and pass through a 200-mesh sieve to obtain halloysite nanotubes wrapped with polyimide; For every 100 g of the slurry of the coarsely coated halloysite nanotubes with polyamic acid, coat 500 cm 3 of the mold.

[0012] It should be noted that the hollow tube cavity structure with a high aspect ratio of halloysite nanotubes forms a three-dimensional network in the PC / PBT alloy material matrix. The physical cross-linking points restrict the hygrothermal expansion movement of molecular chains. The hollow tube cavity can capture some water molecules, reducing the water absorption of the matrix. Moreover, the tube wall composed of silicate itself has low hygroscopicity. The halloysite nanotubes with a nanoscale particle size dispersed in the PC / PBT alloy material can increase the tortuosity of water molecule diffusion, significantly reducing the hygroscopicity. The rigid aromatic ring structure of the polyimide coating layer has a strong interfacial bond with the PC / PBT alloy material matrix, effectively transmitting the load and hindering the propagation of microcracks. At the same time, the conjugated structure of the rigid aromatic ring and imide in the polyimide molecular chain results in a uniform electron cloud distribution and low surface energy. Its smooth surface and chemical inertness make it naturally hydrophobic. The strong electronegativity of the perfluoroalkyl chain in the perfluoroalkyl-modified boron nitride combines with the π electron cloud of the polyimide aromatic ring through dipole-π interaction and van der Waals force. In addition, the silanol groups of halloysite nanotubes form dynamic coordination bonds with Mg2+ / Al released by magnesium aluminum hydrotalcite 3+ through ion-dipole interaction, dynamically cross-linking and balancing the cross-linking density of the PC / PBT alloy material, relieving the crystallization shrinkage stress of PBT, and maintaining dimensional stability. As previously mentioned, the dynamic hydrogen bond network of ureidopyrimidinone preferentially breaks and dissipates energy under impact load, while the rigid skeleton of the halloysite nanotubes wrapped with polyimide bears the residual stress. The two form a soft-hard alternating energy dissipation system, improving the impact strength while having excellent flexural modulus. In summary, the halloysite nanotubes wrapped with polyimide become the key functional component with dimensional stability, environmental aging resistance, high strength and toughness in the PC / PBT alloy material.

[0013] It should be noted that the epoxy groups on the cage structure of the epoxy-functionalized cage-like octasiloxane undergo ring-opening reactions with the terminal hydroxyl groups of PC and the carboxyl groups of PBT, respectively, forming ether bonds and ester bonds, and forming covalent bonds. At the same time, the epoxy groups can undergo ring-opening reactions with the secondary amino groups in the ureidopyrimidinone-polydimethylsiloxane structure, forming stable C-N covalent bonds, constituting a flexible interface layer, inhibiting stress concentration and microcrack propagation at the two-phase interface, both inhibiting the phase separation of PC and PBT and releasing internal stress through interface slip, further reducing warpage deformation. At the same time, the epoxy-functionalized cage-like octasiloxane can assist magnesium aluminum hydrotalcite in capturing the acidic small molecules generated by the degradation of the PC / PBT alloy material, delaying material aging.

[0014] It should be noted that in the PC / PBT alloy material, magnesium aluminum hydrotalcite exchanges and adsorbs phenolic substances generated by the trace hydrolysis of PC through interlayer CO3 2- to neutralize acidic by-products to maintain the matrix stability of the PC / PBT alloy material. Its lamellar structure is oriented along the flow direction during the melt processing, forming a bionic laminated reinforcement network with liquid crystal polymer microfibrils, and reducing the shrinkage rate and warping tendency by physically blocking the hygrothermal expansion movement of molecular chains.

[0015] It should be noted that in the PC / PBT alloy material, perfluoroalkyl-modified boron nitride nanosheets construct a low surface energy barrier on the material surface through perfluoroalkyl chain segments, cooperate with the polyimide coating layer of halloysite nanotubes wrapped by polyimide to be hydrophobic, and block the water molecule penetration path; the high thermal conductivity of its boron nitride substrate is coupled with the oriented structure of liquid crystal polymer microfibrils to establish a fast heat conduction belt-like channel, evenly disperse local thermal stress, and resist arc impact.

[0016] It should be noted that in the PC / PBT alloy material, liquid crystal polymer microfibrils spontaneously form a highly oriented rigid skeleton in the shear flow field during processing and extrusion. Its negative thermal expansion coefficient partially offsets the positive thermal expansion coefficient of the PC / PBT alloy material matrix, reducing the volume shrinkage during the cooling and crystallization process of the PC / PBT alloy material. At the same time, through the dynamic hydrogen bond network cross-linking of the hydroxyl groups at the microfibril ends and ureidopyrimidinone-polydimethylsiloxane, an energy dissipation system is constructed, enabling the PC / PBT alloy material to have both high modulus and toughness under impact stress.

[0017] A preparation method of a dimensionally stable and warpage-resistant mineral-reinforced PC / PBT alloy material comprises the following steps: S1. Weigh the raw materials according to the ratio and premix to obtain a mixture, add it to a mixer, stir at a speed of 800 - 1000 r / min at 50 °C for 15 - 30 min, add it to a twin-screw extruder, set the temperature range at 160 - 265 °C, and the screw speed at 300 - 400 r / min, and melt-extrude and pelletize to obtain pellets; The temperature range of 160 - 265 °C of the twin-screw extruder is specifically divided as follows: the temperature of the first zone is 160 °C, the temperature of the second zone is 190 °C, the temperature of the third zone is 230 °C, the temperature of the fourth zone is 240 °C, the temperature of the fifth zone is 250 °C, the temperature of the sixth zone is 245 °C, the temperature of the seventh zone is 260 °C, the temperature of the eighth zone is 265 °C, the temperature of the ninth zone is 250 °C, the temperature of the tenth zone is 245 °C, the temperature of the eleventh zone is 240 °C, the die head temperature is 250 °C, and the screw speed is 300 r / min.

[0018] S2. After drying the pellet at 100 - 120 °C for 3 - 4 h, add it to the injection molding machine barrel. Set the temperature of the injection molding machine barrel at 260 - 275 °C, the mold temperature at 80 °C, and the holding pressure at 80 MPa, and perform injection molding to obtain the crude product. S3. Place the crude product in a constant temperature and humidity chamber at 25 °C and 50% humidity, and let it stand for 48 h to obtain the product.

[0019] Compared with the prior art, the present invention has the following beneficial effects: Through mineral reinforcement and interface co - design, the present invention significantly improves the comprehensive performance of the dimension - stable and warpage - resistant mineral - reinforced PC / PBT alloy material in complex underwater environments, and provides a PBT / PC alloy material for consumer - grade and industrial - grade underwater plastic components, which integrates the advantages of dimension stability, warpage resistance, low shrinkage rate, low hygroscopicity, creep resistance, impact resistance, arc resistance, and chemical corrosion resistance. Specific Embodiments

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0021] The sources and parameters of some materials are shown in Table 1:

[0022] (1) The preparation steps of ureidopyrimidinone - polydimethylsiloxane are as follows: A1. Under nitrogen protection, mix 10 g of 2 - amino - 4 - hydroxy - 6 - methylpyrimidine with 65 g of hexamethylene diisocyanate, reflux at 120 °C for 12 h, add petroleum ether, perform suction filtration, and dry to obtain the isocyanate - terminated intermediate. A2. Dissolve 100 g of amino - terminated polydimethylsiloxane in 300 mL of toluene, preheat at 80 °C for 15 min, add 120 g of the isocyanate - terminated intermediate, react at a stirring speed of 600 r / min for 12 h, cool the reaction solution to room temperature, precipitate it in 1500 mL of n - hexane, perform centrifugation, washing, and vacuum dry at 60 °C for 24 h to obtain ureidopyrimidinone - polydimethylsiloxane.

[0023] (2) The preparation steps of polyimide - coated halloysite nanotubes are as follows: B1. Mix 120 g of halloysite nanotubes with 600 mL of a hydrochloric acid solution with a concentration of 3 mol / L, perform ultrasonic dispersion for 30 min, stir at 60 °C for 2 h, perform centrifugation, wash until neutral, and dry at 80 °C for 12 h to obtain the pickled halloysite nanotubes. B2. At 0 °C in an ice-water bath, dissolve 40 g of pyromellitic dianhydride and 35 g of 4,4'-diaminodiphenyl ether in 1000 mL of N-methylpyrrolidone. Add 100 g of acid-washed halloysite nanotubes, ultrasonically disperse for 1 h, raise the temperature to 45 °C and react for 4 h to form a crude slurry of halloysite nanotubes coated with polyamic acid; B3. Uniformly coat 100 g of the crude halloysite nanotubes coated with polyamic acid on a 500 cm 3 mold, raise the temperature to 300 °C at a gradient of 60 °C / h, keep warm for 2 h, cool and demold, mechanically crush, and pass through a 200-mesh sieve to obtain halloysite nanotubes wrapped with polyimide; Example 1

[0024] A dimensionally stable and warp-resistant mineral-reinforced PC / PBT alloy material, comprising the following raw material components by weight: Polycarbonate (PC) 60 parts; Polybutylene terephthalate (PBT) 40 parts; Ureidopyrimidinone-polydimethylsiloxane 7.5 parts; Epoxy-functionalized cage-like octasilsesquioxane 2.5 parts; Halloysite nanotubes wrapped with polyimide 8 parts; Magnesium aluminum hydrotalcite 4 parts; Perfluoroalkyl-modified boron nitride nanosheets 5 parts; Liquid crystal polymer microfibrils 3 parts; Modified PVA fibers 1.6 parts; Silane coupling agent KH550 0.25 parts; Polycarbodiimide 0.8 parts; Antioxidant 1010 0.2 parts; Antioxidant 168 0.2 parts; A preparation method of a dimensionally stable and warp-resistant mineral-reinforced PC / PBT alloy material, comprising the following steps: S1. Weigh the raw materials according to the ratio and premix to obtain a mixture. Add it to a mixer and stir at 800 r / min at 50 °C for 15 min. Then add it to a twin-screw extruder. Set the temperature of zone 1 to 160 °C, zone 2 to 190 °C, zone 3 to 230 °C, zone 4 to 240 °C, zone 5 to 250 °C, zone 6 to 245 °C, zone 7 to 260 °C, zone 8 to 265 °C, zone 9 to 250 °C, zone 10 to 245 °C, zone 11 to 240 °C, and the die temperature to 250 °C. The screw speed is 300 r / min. Melt and extrude to granulate to obtain pellets; S2. After drying the pellet at 100 °C for 4 h, add it to the barrel of the injection molding machine. Set the barrel temperature of the injection molding machine to 270 °C, the mold temperature to 80 °C, and the holding pressure to 80 MPa, and perform injection molding to obtain the crude product; S3. Place the crude product in a constant temperature and humidity chamber at 25 °C and 50% humidity, and let it stand for 48 h to obtain the product. Example 2

[0025] A dimensionally stable and warpage-resistant mineral-reinforced PC / PBT alloy material comprises the following raw material components by weight: 55 parts of polycarbonate (PC); 45 parts of polybutylene terephthalate (PBT); 6 parts of ureidopyrimidinone-polydimethylsiloxane; 2 parts of epoxy-functionalized cage-like octasilsesquioxane; 6 parts of polyimide-coated halloysite nanotubes; 3 parts of magnesium aluminum hydrotalcite; 4 parts of perfluoroalkyl-modified boron nitride nanosheets; 2 parts of liquid crystal polymer microfibers; 1.2 parts of modified PVA fibers; 0.2 part of silane coupling agent KH550; 0.6 part of polycarbodiimide; 0.15 part of antioxidant 1010; 0.15 part of antioxidant 168; A preparation method of a dimensionally stable and warpage-resistant mineral-reinforced PC / PBT alloy material comprises the following steps: S1. Weigh the raw materials according to the ratio and premix to obtain a mixture. Add it to a mixer and stir at 50 °C at a speed of 800 r / min for 15 min. Then add it to a twin-screw extruder. Set the temperature of zone 1 to 160 °C, zone 2 to 190 °C, zone 3 to 230 °C, zone 4 to 240 °C, zone 5 to 250 °C, zone 6 to 245 °C, zone 7 to 260 °C, zone 8 to 265 °C, zone 9 to 250 °C, zone 10 to 245 °C, zone 11 to 240 °C, and the die temperature to 250 °C. Set the screw speed to 300 r / min and perform melt extrusion granulation to obtain pellets; S2. After drying the pellet at 100 °C for 4 h, add it to the barrel of the injection molding machine. Set the barrel temperature of the injection molding machine to 270 °C, the mold temperature to 80 °C, and the holding pressure to 80 MPa, and perform injection molding to obtain the crude product; S3. Place the crude product in a constant temperature and humidity chamber at 25 °C and 50% humidity, and let it stand for 48 h to obtain the product. Example 3

[0026] A dimensionally stable and warpage-resistant mineral-reinforced PC / PBT alloy material, comprising the following raw material components by weight parts: Polycarbonate (PC) 65 parts; Polybutylene terephthalate (PBT) 35 parts; Ureidopyrimidinone-polydimethylsiloxane 9 parts; Epoxy-functionalized cage-like octasilsesquioxane 3 parts; Polyimide-coated halloysite nanotubes 10 parts; Magnesium aluminum hydrotalcite 5 parts; Perfluoroalkyl-modified boron nitride nanosheets 6 parts; Liquid crystal polymer microfibrils 4 parts; Modified PVA fibers 1.8 parts; Silane coupling agent KH550 0.3 parts; Polycarbodiimide 1 part; Antioxidant 1010 0.25 parts; Antioxidant 168 0.25 parts; A preparation method of a dimensionally stable and warpage-resistant mineral-reinforced PC / PBT alloy material, comprising the following steps: S1. Weigh the raw materials according to the ratio and premix them to obtain a mixture. Add the mixture to a mixer and stir at a speed of 800 r / min at 50 °C for 15 min. Then add it to a twin-screw extruder. Set the temperature of zone 1 to 160 °C, zone 2 to 190 °C, zone 3 to 230 °C, zone 4 to 240 °C, zone 5 to 250 °C, zone 6 to 245 °C, zone 7 to 260 °C, zone 8 to 265 °C, zone 9 to 250 °C, zone 10 to 245 °C, zone 11 to 240 °C, and the die temperature to 250 °C. Set the screw speed to 300 r / min, melt extrude and pelletize to obtain pellets; S2. After drying the pellets at 100 °C for 4 h, add them to the barrel of an injection molding machine. Set the temperature of the barrel of the injection molding machine to 270 °C, the mold temperature to 80 °C, and the holding pressure to 80 MPa, and injection mold to obtain a crude product; S3. Place the crude product in a constant temperature and humidity chamber at 25 °C and 50% humidity and let it stand for 48 h to obtain the product.

[0027] Comparative Example 1 The difference between this comparative example and Example 1 is that ureidopyrimidinone-polydimethylsiloxane is not added.

[0028] Comparative Example 2 The difference between this comparative example and Example 1 is that polyimide-coated halloysite nanotubes are not added.

[0029] Test: I. Mechanical properties Tensile strength and elongation at break: "GB / T 1040.1-2018 Plastics - Determination of tensile properties - Part 1: General principles" Flexural strength: "GB / T 9341-2008 Plastics - Determination of flexural properties" Impact strength: "GB / T 1843-2008 Plastics - Determination of izod impact strength" The test results are shown in Table 2: It can be seen from Table 2 that the mechanical properties of the samples in Examples 1-3 are significantly better than those in Comparative Examples 1-2. The synergistic effect of the dynamic hydrogen bond network of ureidopyrimidinone-polydimethylsiloxane and the rigid skeleton of polyimide-coated halloysite nanotubes improves the toughness and rigidity of the material.

[0030] II. Dimensional stability Coefficient of linear thermal expansion (CLTE): "ISO 11359-2:2021 Plastics - Thermomechanical analysis (TMA) - Part 2: Determination of coefficient of linear thermal expansion and glass transition temperature" Creep strain: "ISO 899-1:2017 Plastics - Determination of creep properties - Part 1: Tensile creep" Moisture absorption rate: "ASTM D570-98 Standard Test Method for Water Absorption of Plastics" The test results are shown in Table 3:

[0031] It can be seen from Table 3 that the dimensional stability of the samples in Examples 1-3 is significantly better than that in Comparative Examples 1-2. The synergistic effect of polyimide-coated halloysite nanotubes and liquid crystal polymer microfibrils significantly reduces the coefficient of linear thermal expansion and moisture absorption rate of Examples 1-3; ureidopyrimidinone-polydimethylsiloxane significantly inhibits creep.

[0032] III. Environmental resistance Underwater pressure cycle simulation test: The specimens are dried in an oven at 50 °C for 4 h, weighed after cooling to room temperature, deionized water at 25 °C is injected into the high-pressure water tank, and the pressure change parameters are set: 0.1 - 0.5 MPa, pressure change frequency 0.1 Hz. After 7 days, they are cleaned and dried, and tested: Sealability: Visual inspection Moisture absorption rate change (ΔW): Gravimetric method Tensile strength retention rate after underwater pressure cycle: "GB / T 1040.1-2018 Plastics - Determination of tensile properties - Part 1: General principles" Formula: Tensile strength retention rate after underwater pressure cycle = Tensile strength after corrosion / Original tensile strength × 100% The test results are shown in Table 4:

[0033] As can be seen from Table 4, the samples of Examples 1-3 have high adaptability to underwater pressure shock.

[0034] IV. Chemical corrosion resistance Oil / coolant immersion (mass loss Δm): "ASTM D543-21 Standard Practice for Evaluating the Chemical Resistance of Plastics" Tensile strength retention rate after chemical corrosion: "GB / T 1040.1-2018 Plastics - Determination of tensile properties - Part 1: General principles" Formula: Tensile strength retention rate after chemical corrosion = Tensile strength after corrosion / Original tensile strength × 100% The test results are shown in Table 5:

[0035] As can be seen from Table 5, the samples of Examples 1-3 have excellent chemical corrosion resistance.

[0036] V. Electrical properties (arc resistance) Comparative tracking index (CTI): "GB / T 4207-2022 Determination of Comparative Tracking Index and Proof Tracking Index of Solid Insulating Materials" Proof tracking index (PTI): "GB / T 4207-2022 Determination of Comparative Tracking Index and Proof Tracking Index of Solid Insulating Materials" The test results of Table 2 are shown in Table 6:

[0037] As can be seen from Table 6, the samples of Examples 1-3 have excellent arc breakdown resistance and meet the performance safety requirements of underwater equipment.

[0038] In the description of the specification, the description of reference terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0039] The above content is only an example and illustration of the present invention. Those skilled in the art of the present technology make various modifications or supplements to the described specific embodiments or use similar methods to replace them. As long as they do not deviate from the invention or exceed the scope defined by the claims of the present invention, they should fall within the protection scope of the present invention.

Claims

1. A dimensionally stable and warpage-resistant mineral-reinforced PC / PBT alloy material, characterized in that: Comprising the following raw material components by weight portions: Polycarbonate 55 - 65 parts; Polybutylene terephthalate 35 - 45 parts; Ureidopyrimidinone - polydimethylsiloxane 6 - 9 parts; Epoxy - caged silsesquioxane 2 - 3 parts; Polyimide - coated halloysite nanotubes 6 - 10 parts; Magnesium - aluminum hydrotalcite 3 - 5 parts; Perfluoroalkane - modified boron nitride nanosheets 4 - 6 parts; Liquid crystal polymer microfibers 2 - 4 parts; Modified PVA fibers 1.2 - 1.8 parts; Silane coupling agent KH550 0.2 - 0.3 parts; Polycarbodiimide 0.6 - 1 part; Compound antioxidant 0.3 - 0.5 part.

2. The dimensionally stable and warpage-resistant mineral-reinforced PC / PBT alloy material according to claim 1, wherein: The total weight portions of the polycarbonate and polybutylene terephthalate are 100 parts.

3. A dimensionally stable and warpage-resistant mineral-reinforced PC / PBT alloy material according to claim 1, characterized in that: The weight ratio of the ureidopyrimidinone - polydimethylsiloxane to the epoxidized epoxy - caged silsesquioxane is 3:

1.

4. A dimensionally stable and warpage-resistant mineral-reinforced PC / PBT alloy material according to claim 1, characterized in that: The weight ratio of the polyimide - coated halloysite nanotubes to the magnesium - aluminum hydrotalcite is 2:

1.

5. A dimensionally stable and warpage-resistant mineral-reinforced PC / PBT alloy material according to claim 1, characterized in that: The compound antioxidant is a compound of antioxidant 1010 and antioxidant 168 in a ratio of 1:

1.

6. A dimensionally stable and warpage-resistant mineral-reinforced PC / PBT alloy material according to claim 1, characterized in that: The preparation steps of the ureidopyrimidinone - polydimethylsiloxane are as follows: A1. Under nitrogen protection, mix 2 - amino - 4 - hydroxy - 6 - methylpyrimidine with hexamethylene diisocyanate, reflux and react at 110 - 130 °C for 12 - 14 h, add petroleum ether, filter by suction, and dry to obtain an isocyanate - terminated intermediate; The dosage ratio of the 2 - amino - 4 - hydroxy - 6 - methylpyrimidine to the hexamethylene diisocyanate is 10 g:(64 - 72) g; A2. Dissolve the amino - terminated polydimethylsiloxane in toluene, pre - heat at 80 - 90 °C for 15 min, add the isocyanate - terminated intermediate, react under stirring at a speed of 500 - 800 r / min for 12 - 14 h, cool the reaction solution to room temperature, precipitate in n - hexane, centrifuge, wash, and vacuum - dry at 60 - 65 °C for 24 h to obtain ureidopyrimidinone - polydimethylsiloxane.

7. A dimensionally stable and warpage-resistant mineral-reinforced PC / PBT alloy material according to claim 6, characterized in that: In the step A2, the dosage ratio of the amino - terminated polydimethylsiloxane, toluene, isocyanate - terminated intermediate, and n - hexane is 100 g:300 mL:(117 - 123) g:1500 mL.

8. A dimensionally stable and warpage-resistant mineral-reinforced PC / PBT alloy material according to claim 1, characterized in that: The preparation steps of the polyimide - coated halloysite nanotubes are as follows: B1. Mix the halloysite nanotubes with a hydrochloric acid solution, ultrasonically disperse for 30 - 45 min, stir at 60 °C for 2 - 3 h, centrifuge, wash until neutral, and dry at 80 - 90 °C for 12 - 14 h to obtain pickled halloysite nanotubes; The concentration of the hydrochloric acid solution is (2.4 - 3) mol / L; The dosage ratio of the halloysite nanotubes to the hydrochloric acid is (80 - 120) g:500 mL; B2. Under an ice - water bath at 0 - 5 °C, dissolve pyromellitic dianhydride and 4,4 - diamino - diphenyl ether in N - methylpyrrolidone, add the pickled halloysite nanotubes, ultrasonically disperse for 1 h, raise the temperature to 45 - 49 °C and react for 4 h to form a crude slurry of polyamic acid - coated halloysite nanotubes; B3. Uniformly coat the crude polyamic acid-coated halloysite nanotubes in a mold, heat them up to 300 °C at a gradient of 60 °C / h, hold for 2 h, cool and demold, mechanically crush, and pass through a 200-mesh sieve to obtain halloysite nanotubes wrapped with polyimide; 500 cm of the coating is applied to every 100 g of the crude polyamic acid-coated halloysite nanotube slurry 3 mold.

9. The dimensionally stable and warpage-resistant mineral-reinforced PC / PBT alloy material according to claim 8, wherein: In the step B2, the dosage ratio of the pickled halloysite nanotubes, pyromellitic dianhydride, 4,4'-diaminodiphenyl ether, and N-methylpyrrolidone is 100 g: (35-45) g: (34-36) g: 1000 mL.

10. A preparation method of a dimensionally stable and warpage-resistant mineral-reinforced PC / PBT alloy material according to any one of claims 1-9, comprising the following steps: S1. Weigh the raw materials according to the ratio and premix them to obtain a mixture. Add it to a mixer and stir at a speed of 800-1000 r / min at 50 °C for 15-30 min. Then add it to a twin-screw extruder, set the temperature range at 160-265 °C, and the screw speed at 300-400 r / min, and melt and extrude to granulate to obtain pellets; S2. After drying the pellets at 100-120 °C for 3-4 h, add them to the barrel of an injection molding machine. Set the temperature of the barrel of the injection molding machine at 260-275 °C, the mold temperature at 80 °C, and the holding pressure at 80 MPa, and injection mold to obtain a crude product; S3. Place the crude product in a constant temperature and humidity box at a temperature of 25 °C and a humidity of 50%, and let it stand for 48 h to obtain the product.

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