Thermoplastic engineering plastic and preparation method thereof

Abstract

The invention discloses a thermoplastic engineering plastic and a preparation method thereof, and the thermoplastic engineering plastic comprises the following components by weight: 83-93% of ABS resin, 3-10% of flake alumina and 3-4% of a processing aid; wherein the surface of the flaky aluminum oxide is connected with a lipophilic group. According to the invention, the surface-modified flaky aluminum oxide is adopted as a functional filler and is compounded with the ABS resin to prepare the ABS thermoplastic engineering plastic, and the flaky aluminum oxide can realize single-sheet stripping after being subjected to surface treatment, so that the characteristics of portability, impact resistance, weather resistance and great improvement of dimensional stability can be achieved only by using 3-10% of additive amount; meanwhile, the production cost of the ABS plastic and the increase amplitude of the overall weight are reduced due to the low filler addition amount, and no obvious adverse effect is generated on the mechanical property of the plastic; the preparation method does not need to change the forming processing technology of the existing ABS plastic, the production cost is low, and the product can be recycled.

Description

Technical Field

[0001] This application relates to the field of functional polymer materials, and more particularly to a thermoplastic engineering plastic and its preparation method. Background Technology

[0002] ABS plastic is a thermoplastic engineering plastic formed by a terpolymer of acrylonitrile (A), butadiene (B), and styrene (S). However, due to the inherent molecular structure of thermoplastics, ABS plastic typically has a high coefficient of thermal expansion, resulting in significant dimensional changes when heated. Currently, the main method to improve the dimensional stability of ABS plastic is filler modification, which involves adding functional fillers to the matrix resin to improve its dimensional stability. However, the percentage of functional fillers used is often too high, severely affecting the appearance and properties of the ABS plastic. Furthermore, some functional fillers are not directly compatible with the resin, requiring the addition of coupling agents, plasticizers, or graft copolymerization of ABS monomers such as polybutadiene and styrene. This process is cumbersome, technically demanding, requires significant equipment investment, and has high production costs. Summary of the Invention

[0003] In view of this, this application provides a thermoplastic engineering plastic and a method for preparing the same, which aims to improve the compatibility of fillers in resin to enhance the dimensional stability of ABS plastic, without changing the existing ABS plastic molding and processing technology and with lower production costs.

[0004] The embodiments of this application are implemented as follows: a thermoplastic engineering plastic of this application, by weight percentage, comprises: 83-93% ABS resin, 3-10% flake alumina and 3-4% processing aids;

[0005] The surface of the sheet-like alumina is connected with lipophilic groups.

[0006] In some embodiments, the sheet-like alumina has a long side and a short side; the length of the long side is a μm, the length of the short side is b μm, and the thickness of the sheet-like alumina is c μm, satisfying: 50 < (a + b) / c < 225, and 500 < (a × b) / c 2 <8000.

[0007] In some embodiments, the lipophilic group is selected from at least one of alkyl, aliphatic hydrocarbon, aromatic hydrocarbon, alkoxy, ester, and aliphatic ether groups.

[0008] In some embodiments, the sheet-like alumina further satisfies at least one of the following characteristics:

[0009] 1) The plate-like alumina has an α-phase single-crystal structure;

[0010] 2) The Mohs hardness of the sheet-like alumina is 8-10;

[0011] 3) 40 ≤ a / c ≤ 120;

[0012] 4) 15 ≤ a ≤ 30;

[0013] 5) 5 ≤ b ≤ 15;

[0014] 6) 0.2≤c≤0.4.

[0015] In some embodiments, the processing aid is selected from at least one of plasticizers, lubricants, and antioxidants.

[0016] In some embodiments, this application also provides a method for preparing a thermoplastic engineering plastic, comprising the following steps:

[0017] A flake-shaped alumina raw material, a surface modifier, and a catalyst are taken and reacted by heating and reflux to obtain flake-shaped alumina with lipophilic groups attached to its surface.

[0018] A thermoplastic engineering plastic is obtained by mixing and extruding flake-shaped alumina with oleophilic groups attached to its surface, ABS resin, and processing aids.

[0019] In some embodiments, the surface modifier is an isocyanate containing a lipophilic group; the lipophilic group is selected from at least one of alkyl, aliphatic hydrocarbon, aromatic hydrocarbon, alkoxy, ester, and aliphatic ether groups.

[0020] In some embodiments, the surface modifier is selected from at least one of methyl methyl isocyanate, benzyl isocyanate, p-chlorophenyl isocyanate, 2-benzyl isocyanate, phenyl isocyanate, ethyl isocyanate, chloroethyl isocyanate, 3-ethylphenyl isocyanate, butyrate isocyanate, and ethoxyisocyanate.

[0021] In some embodiments, the mass ratio of the sheet-like alumina raw material, the surface modifier, and the catalyst is 20:(20-24):(1-2).

[0022] In some embodiments, the heating temperature is 75-95°C, and the reflux reaction time is 0.5-3 hours.

[0023] The beneficial effects of this application are as follows:

[0024] This application uses surface-modified flake alumina as a functional filler, and combines it with ABS resin to prepare ABS thermoplastic engineering plastic. Since the flake alumina can be peeled off in single pieces after surface treatment, only 3-10% of the addition amount is needed to achieve the characteristics of being lightweight, impact-resistant, weather-resistant, and having significantly improved dimensional stability. At the same time, the low amount of filler added reduces the production cost and the increase in overall weight of ABS plastic, and has no significant adverse effect on the mechanical properties of the plastic. The preparation method of this application does not require changes to the existing molding and processing technology of ABS plastic, has low production cost, and the product is recyclable. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a scanning electron microscope image of the sheet-like alumina used in Example 1 of this application;

[0027] Figure 2 This is another scanning electron microscope image of the sheet-like alumina used in Example 1 of this application;

[0028] Figure 3 This is a single-crystal diffraction pattern of the sheet-like alumina used in Example 1 of this application;

[0029] Figure 4 This is a microscopic image of the ABS thermoplastic engineering plastic prepared in Example 1 of this application. Detailed Implementation

[0030] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. In addition, in the description of this application, the term "including" means "including but not limited to". Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and conciseness and should not be construed as a hard limitation on the scope of the present invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single values ​​within that range. For example, it should be assumed that the description of a range from 1 to 6 specifically discloses subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the range referred to.

[0031] The inventors of this application have discovered that ABS resin possesses good toughness, low-temperature resistance, and heat and impact resistance. Its price is moderate, lower than PC, PA, and PPE, and it is widely used in household appliance housings, automotive interior and exterior trim, office supplies, kitchenware, instruments, building materials, and pipes. It is a high-performance, widely applied thermoplastic engineering plastic. However, ABS has poor internal stress and weak flexural and compressive strength. Although ABS parts typically have high tensile strength, their poor fatigue resistance prevents them from withstanding heavy loads for extended periods, hindering their wider market application. Furthermore, thermoplastics typically exhibit a high coefficient of thermal expansion due to their molecular structure, meaning they undergo significant dimensional changes when heated.

[0032] In terms of specific processability, the common methods for improving ABS materials currently fall into two main categories: filler modification and blending modification. First, blending modification primarily involves melt-extruding and blending two resins with certain compatibility to minimize the rubber content and adding N-substituted maleimide copolymers. Although N-substituted maleimide copolymers impart improved heat resistance and a low linear coefficient of thermal expansion, they do not provide sufficient impact resistance and crack at low temperatures, thus limiting their application and incurring high costs. Second, filler modification. Functional fillers are solid additives that, when added to the matrix resin, can improve its properties. Considering the cost of research and development and production, in the engineering plastics field, a widely accepted and common practice is to use fillers to improve the physical properties of molded parts. The addition of fillers can significantly improve the material's tensile strength, hardness, impact resistance, toughness, and flexural capacity, while effectively reducing creep and molding shrinkage. Common types of fillers include organic rigid particle reinforcement systems and inorganic rigid ionic systems. The former mainly includes SAN and PMMA, but due to their high cost, they are mostly confined to laboratory research. Inorganic particles such as carbon / graphite fibers, talc, clay, marble, limestone, and whisker-based inorganic crystalline salts such as barite and barium sulfate have entered a more widespread application stage. Fillers in resins can improve a specific property of composite materials. For example, to improve the excellent electrical conductivity and electromagnetic shielding properties of ABS resin, carbon materials such as graphene and carbon fibers can be added to the resin. The aforementioned inorganic fillers are generally selected at the micron / nanoscale level. Their high surface activation energy and large surface area can play a reinforcing role in the resin. However, due to their high surface energy, the particles are in a thermodynamically unstable state and are prone to agglomeration during processing, making them difficult to disperse uniformly in the matrix rubber. Furthermore, inorganic filler particles are hydrophilic and oleophobic, and have weak interfacial bonding with polymer resins, making them very easy to desorb from the resin, forming voids or pores, leading to a significant decrease in the mechanical properties of the composite material. Needle-shaped barium sulfate, magnesium salt whiskers, and needle-shaped calcium metasilicates are more easily broken by mechanical forces during processing and are even less adaptable. Current technologies for ABS dimensional stability research have the following shortcomings: 1. The filler percentage is too high. Currently, fillers account for 20-70% of the total plastic weight, meaning the main component of the plastic is filler rather than resin. This significantly diminishes the lightweight advantage of engineering plastics, resulting in poor appearance and texture, and making it difficult to process through extrusion or blow molding processes, especially for consumer products; 2. The process is complex. Inorganic fillers and resin cannot be directly mixed, requiring the addition of coupling agents and plasticizers, or separate graft copolymerization of ABS monomers such as polybutadiene and styrene. This process is cumbersome, difficult, and requires significant equipment investment, leading to high production costs. Furthermore, this method inevitably introduces different types of polymers and adhesives during molding, forming a difficult-to-separate polymer mixture that is hard to recycle.

[0033] Therefore, this application provides a thermoplastic engineering plastic and a method for preparing the same, addressing the aforementioned problems. Detailed descriptions follow. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments.

[0034] This application provides a thermoplastic engineering plastic, which, by weight percentage, comprises: 83-93% ABS resin, 3-10% flake alumina, and 3-4% processing aids; wherein the surface of the flake alumina is attached with lipophilic groups.

[0035] Understandably, the enhanced interfacial bonding between the lamellar alumina surface and the matrix resin is due to the presence of lipophilic groups. This is because the introduction of these lipophilic groups improves the chemical affinity of the lamellar alumina surface, enabling it to adsorb and interact with lipophilic substances in the matrix resin. This chemical affinity improves interfacial compatibility and promotes intermolecular interactions, thereby strengthening the interfacial bonding. Simultaneously, the presence of these lipophilic groups modulates the surface energy of the lamellar alumina surface, bringing it closer to the surface energy of the matrix resin. This surface energy matching helps reduce the energy difference at the interface, thus… It reduces interfacial tension and enhances interfacial adhesion. Furthermore, the introduction of lipophilic groups can increase the surface roughness and surface area of ​​the lamellar alumina, providing more mechanical anchoring points. These mechanical anchoring points can increase the physical connection of the interface, enhance interfacial adhesion, and prevent interfacial peeling and shearing. In summary, only 3-10% of lamellar alumina is needed to achieve good modification functions. Since the distribution of lamellar alumina is more uniform, it can further improve the dimensional stability of ABS plastic. Moreover, the small amount has no adverse effect on other mechanical properties of ABS plastic, and the product can be directly recycled after use.

[0036] In some embodiments, the sheet-like alumina has a long side and a short side; the length of the long side is a μm, the length of the short side is b μm, and the thickness of the sheet-like alumina is c μm, satisfying: 50 < (a + b) / c < 225, and 500 < (a × b) / c 2 <8000; It should be noted that lamellar alumina is an alumina material with a lamellar morphology, resembling thin sheets or plate-like crystals. When describing the shape of lamellar alumina, its dimensions are often indicated by its long side and short side. The long side refers to the longer boundary line or edge of the lamellar alumina, usually in the length direction; the short side refers to the shorter boundary line or edge, usually in the width direction.

[0037] It is understandable that when 50 < (a + b) / c < 225 and 500 < (a × b) / c 2When the size ratio is less than 8000, the flake alumina exhibits the typical appearance of a two-dimensional material. The two-dimensional flake alumina can be randomly oriented within the ABS resin, making the difference between its longitudinal (mechine direction) and transverse (transverse direction) relatively equal. The two-dimensional flat structure makes the flake alumina less prone to bending, warping, or shrinkage. In particular, when the temperature changes, the dimensional change trends of the ABS resin and the flake alumina are relatively consistent, reducing the stress accumulation caused by the mismatch of thermal expansion, thus giving the ABS plastic good dimensional stability.

[0038] In some embodiments, the lamellar alumina is an α-phase single-crystal structure. It is understood that α-phase single-crystal lamellar alumina typically has high purity, free from impurities and defects, making it more reliable and stable in applications, providing consistent performance. Furthermore, α-phase single-crystal lamellar alumina possesses excellent physical properties, such as high hardness, high melting point, high thermal conductivity, and excellent electrical insulation. In addition, α-phase single-crystal lamellar alumina has a uniform crystal structure and grain distribution, which allows for better control of the material's properties and characteristics in applications. Moreover, α-phase single-crystal lamellar alumina has high strength and rigidity, capable of withstanding significant forces and pressures, resulting in good mechanical properties in plastics. α-phase single-crystal lamellar alumina also has a high melting point and thermal stability, maintaining stable physical properties at high temperatures.

[0039] In some embodiments, the Mohs hardness of the flake alumina is 8 to 10, preferably 9; the flake alumina has excellent chemical stability, extremely high hardness and smooth surface, and simultaneously satisfies the requirements of high surface hardness and high smoothness, wear resistance and impact resistance, which can further improve the mechanical properties of ABS plastic.

[0040] In some embodiments, the lamellar alumina further satisfies: 40 ≤ a / c ≤ 120; where a / c can characterize the aspect ratio of the lamellar alumina. When a / c meets the above range, the lamellar alumina exhibits a higher aspect ratio, which can further improve the rigidity and strength of the lamellar alumina; it can also increase the contact area between the lamellar alumina and the matrix resin, which helps to increase the interfacial bonding force and improve the interfacial strength and durability of the composite material. The value of a / c can be any one of 40, 50, 60, 80, and 120, or a range between any two values.

[0041] In some embodiments, the flake alumina further satisfies: 15 ≤ a ≤ 30; for example, a can be any one of 15, 20, 25, 30 or a range between any two values.

[0042] In some embodiments, the flake alumina further satisfies: 5 ≤ b ≤ 15; for example, b can be any one of 5, 7, 9, 11, 15 or a range between any two values.

[0043] In some embodiments, the flake alumina further satisfies: 0.2 ≤ c ≤ 0.4; for example, c can be any one of 0.2, 0.25, 0.3, 0.35, 0.4 or a range between any two values.

[0044] It is understandable that when the long side, short side, and thickness of the flake alumina meet the above dimensional range, the dimensional stability of ABS plastic can be significantly improved. As an inorganic filler, combined with targeted dispersion and modification processes, it can effectively solve the problem of poor dimensional stability of thermoplastic plastics.

[0045] In some embodiments, the lipophilic group is selected from at least one of alkyl, aliphatic hydrocarbon, aromatic hydrocarbon, alkoxy, ester, and aliphatic ether groups. Understandably, the introduction of lipophilic groups can increase the interfacial compatibility between lamellar alumina and the matrix material. This means that the lipophilic groups can adsorb and interact with lipophilic substances in the matrix material, reducing interfacial energy differences and improving interfacial compatibility and interaction capabilities. The presence of lipophilic groups can also enhance the interfacial bonding force between lamellar alumina and the matrix material. The lipophilic groups can form strong physical or chemical bonds with the matrix material, increasing interfacial adhesion and bonding strength, thereby enhancing the overall performance and durability of the composite material. The introduction of lipophilic groups can also improve the dispersibility of lamellar alumina. The lipophilic groups can interact with solvents or dispersants in the matrix material, making it easier for lamellar alumina to disperse in the matrix material, reducing agglomeration and deposition, and improving the uniformity and stability of the material. The presence of lipophilic groups can also improve the durability of lamellar alumina. The lipophilic groups can form a protective interfacial layer, preventing the lamellar alumina from contacting the external environment, reducing oxidation, corrosion, and degradation, and extending the material's service life. Of course, different types of lipophilic groups have different chemical properties and functions, and appropriate lipophilic groups can be selected according to specific needs. For example, alkyl and aliphatic hydrocarbon groups can improve the wear resistance and heat resistance of materials, aromatic hydrocarbon groups can improve the chemical resistance of materials, alkoxy groups and ester groups can improve the softness and processability of materials, and aliphatic ether groups can improve the weather resistance and aging resistance of materials.

[0046] In some embodiments, the processing aid is selected from at least one of plasticizers, lubricants, and antioxidants; it is understood that plasticizers can increase the ductility and flexibility of materials, making them softer and easier to process. This helps improve the plasticity and formability of materials, making them easier to perform various processing operations, such as extrusion, injection molding, and calendering. Lubricants can form a lubricating film between materials, reducing friction and wear. This helps improve the wear resistance and durability of materials, extending their service life.

[0047] In some embodiments, a method for preparing a thermoplastic engineering plastic is also provided, comprising the following steps:

[0048] A flake-shaped alumina raw material, a surface modifier, and a catalyst are taken and reacted by heating and reflux to obtain flake-shaped alumina with lipophilic groups attached to its surface.

[0049] A thermoplastic engineering plastic is obtained by mixing and extruding flake-shaped alumina with oleophilic groups attached to its surface, ABS resin, and processing aids.

[0050] It is understood that the method in this embodiment uses surface-modified flake alumina as a functional filler, which is then combined with ABS resin to prepare ABS / alumina composite plastic. This achieves the inherent characteristics of ABS material—lightweight, reliable, impact-resistant, and weather-resistant—while significantly improving dimensional stability. Furthermore, it offers advantages such as no need to change existing ABS molding processes, lower production costs, and product recyclability. The flake alumina, after surface modification, can achieve uniform dispersion in the ABS resin matrix. The preparation method can fully utilize existing equipment and processes, resulting in a simple process and low production costs. Compared to general fillers such as calcium carbonate or carbon nanotubes, the pre-treated surface of alumina allows for non-agglomeration, uniform dispersion, and coverage of a larger area. The specially modified alumina surface has chemically cross-linked lipophilic groups, resulting in strong interfacial bonding with the matrix resin. Additionally, the pearlescent properties of the flake alumina can further enhance the appearance and texture of the plastic product.

[0051] In some embodiments, the surface modifier is an isocyanate containing a lipophilic group; the lipophilic group is selected from at least one of alkyl, aliphatic hydrocarbon, aromatic hydrocarbon, alkoxy, ester, and aliphatic ether groups.

[0052] Understandably, surface modification of flake-shaped alumina with isocyanates containing lipophilic groups improves various functional indices of ABS plastics, especially dimensional stability. Isocyanates crosslink with the abundant adsorbed hydroxyl groups on the surface of nanomaterial alumina, while the lipophilic groups at the other end of the isocyanate, such as benzene rings, alkyl groups, and epoxy groups, facilitate its binding within the plastic. After treatment with the hydrophobic groups of isocyanate, only a small amount of alumina is needed. The lipophilic and hydrophobic groups bind and disperse with the ABS matrix, fundamentally solving the agglomeration problem and significantly improving the filling effect. This allows the two-dimensional flake-shaped alumina to be evenly distributed in the plastic despite its disorder, thereby reducing transverse and longitudinal differences and achieving dimensional stability. Alumina can be added directly after pretreatment, peeling off individual flakes; a small amount is sufficient to achieve uniform distribution. Since nano-flake-shaped alumina can be peeled off individually with appropriate treatment, a small amount of addition can achieve the desired effect. The low addition amount results in minimal increase in product production cost and weight, with no significant adverse effects on mechanical properties. The method used in this embodiment forms an alumina and ABS blend, which contains only a single type of resin and inorganic filler. It can be recycled without component separation, thus meeting environmental protection requirements.

[0053] In some embodiments, the surface modifier is selected from at least one of methyl methyl isocyanate, benzyl isocyanate, p-chlorophenyl isocyanate, 2-benzyl isocyanate, phenyl isocyanate, ethyl isocyanate, chloroethyl isocyanate, 3-ethylphenyl isocyanate, butyrate isocyanate, and ethoxyisocyanate; wherein the surface modifier is a monoisocyanate to prevent large-area crosslinking caused by multiple CNO bonds.

[0054] In some embodiments, the mass ratio of the flake alumina raw material, the surface modifier, and the catalyst is 20:(20-24):(1-2). Preferably, the mass ratio of the flake alumina raw material, the surface modifier, and the catalyst is 20:22:2.

[0055] In some embodiments, the heating temperature is 75-95°C, and the reflux reaction time is 0.5-3 hours.

[0056] In some embodiments, the preparation method of this embodiment further includes:

[0057] (1) First, add an appropriate amount of flake alumina raw material into a beaker containing 8-15 times the mass of deionized water, disperse it using an ultrasonic disperser for 10-30 minutes, and then filter it. The flake alumina raw material is a commercially available product, which is artificially synthesized and has high purity. Its structural feature is an α-phase single crystal structure. Its morphological feature is a single piece, presenting a typical appearance of a two-dimensional material.

[0058] (2) Add 300 mL of a mixture of anhydrous ethanol and water (in a volume ratio of 1:3) to a 500 mL two-necked flask, then add dried flake alumina raw material, then add surface modifier and catalyst diethyl stannate (DBTDL), heat and reflux in a water bath at 75-95 °C for 0.5-3 h, filter while hot and wash with hot water, then dry to constant weight. The -N=C=O group in the isocyanate reacts with the -OH group of alumina in a nucleophilic reaction, causing the two to crosslink. The lipophilic group at the other end is also crosslinked, thus obtaining flake alumina with lipophilic groups attached to the surface.

[0059] (3) Weigh 83-93% ABS resin, 3%-10% surface-modified flake alumina, and 3-4% processing aids by weight percentage. Mix them in a high-speed mixer at 60-80℃ for 20 minutes. After mixing, remove impurities by sieve and dry for later use.

[0060] (4) Extrusion molding: The above raw materials are added to a twin-screw extruder for extrusion granulation. The resulting particles are dried at 80°C for 5 hours and then injection molded to obtain plastic finished product samples. The samples are placed at 25°C for 24 hours and then various performance tests are performed.

[0061] It should be noted that this application proposes a simple and low-cost method to simultaneously solve the problems of high shrinkage rate and high tensile and deformation modulus of ABS engineering plastic products, thereby greatly improving their dimensional stability. The method in this embodiment uses modified lamellar alumina with high aspect ratio, high hardness, high chemical stability, and smooth surface as a functional filler. It directly uses functional materials for co-extrusion without changing the existing production line structure, and can improve dimensional stability. It does not require changes to the existing ABS processing technology, and the process is simple, low-cost, and has excellent overall performance.

[0062] To enable those skilled in the art to clearly understand the above-described implementation details and operations, and to demonstrate the significant improvement in the performance of the thermoplastic engineering plastic and its preparation method in the embodiments of this application, the above technical solutions are illustrated below through multiple embodiments.

[0063] A thermoplastic engineering plastic is provided, comprising Examples 1-10 and Comparative Examples 1-5. Comparative Example 1 is pure ABS resin, Comparative Example 2 uses calcium carbonate as filler, Comparative Example 3 uses unmodified flake alumina, and the dimensions of the flake alumina in Comparative Examples 4 and 5 do not satisfy 50 < (a+b) / c < 225 and 500 < (a×b) / c 2 The range is <8000.

[0064] The preparation processes of Examples 1-10 are as follows:

[0065] (1) First, add the flake alumina raw material to a beaker containing 10 times its weight of deionized water, disperse it using an ultrasonic disperser for 20 minutes, and then filter it.

[0066] (2) Add 300 mL of a mixed solution of anhydrous ethanol and water (in a volume ratio of 1:3) to a 500 mL two-necked flask, then add dried flake alumina raw material, then add surface modifier and diethylstannate, heat to hot reflux reaction, filter while hot and wash with hot water, then dry to constant weight to obtain surface modified flake alumina;

[0067] (3) Mix ABS resin, flake alumina and processing aids at 70°C for 20 minutes using a high-speed mixer. After mixing, remove impurities by sieving and dry for later use.

[0068] (4) The mixed components are added to a twin-screw extruder for extrusion granulation. The resulting particles are dried at 80°C for 5 hours and then injection molded to obtain thermoplastic engineering plastics.

[0069] The specific process parameters for Examples 1-10 are shown in Table 1.

[0070] Table 1

[0071]

[0072] The specific components of each embodiment and comparative example are shown in Table 2, where wt% represents the weight percentage content; the specific dimensional parameters of the sheet alumina of each embodiment and comparative example are shown in Table 3.

[0073] Table 2

[0074]

[0075] In Examples 1 and 5, the processing aid consisted of 1 wt% stearic acid, 1.5 wt% 1010 antioxidant, and 1.5 wt% polyethylene wax; in Examples 2, 3, and 6, the processing aid consisted of 1 wt% stearic acid, 1 wt% calcium stearate, 1 wt% 1010 antioxidant, and 1 wt% polyethylene wax; in Examples 4 and Examples 8 and 10, the processing aid consisted of 1 wt% stearic acid, 1 wt% 1010 antioxidant, and 1 wt% polyethylene wax; in Examples 7 and 9, the processing aid consisted of 1 wt% calcium stearate, 1 wt% 1010 antioxidant, and 1.5 wt% polyethylene wax; and in Comparative Examples 2-5, the processing aid was the same as in Example 1.

[0076] The dimensional parameters of the lamellar alumina in Examples 1-10 and Comparative Examples 1-5 are shown in Table 3. The long side a, short side b, and thickness c were obtained as follows: multiple sets of electron microscope (SEM) images of the lamellar alumina were taken using a scanning electron microscope (SEM). A lamellar alumina with a complete morphology was selected from the images, and the dimensions of the longest and shortest visible sides were measured and taken as a and b, respectively. Thickness c could be directly obtained from the SEM images. The long side a, short side b, and thickness c were each obtained by averaging 10 sets of measured data.

[0077] Table 3

[0078] a μm b μm c μm a / c (a+b) / c (a x b) / c 2 ]] Example 1 20 5 0.2 100 125 2500 Example 2 15 6 0.25 60 84 1440 Example 3 17 10 0.38 45 71 1177 Example 4 29 12 0.32 91 128 3398 Example 5 25 7 0.28 89 114 2232 Example 6 19 5 0.25 76 96 1520 Example 7 28 15 0.25 112 172 6720 Example 8 22 8 0.22 100 136 3636 Example 9 17 8 0.38 45 66 942 Example 10 24 7 0.25 96 124 2688 Comparative Example 1 / / / / / / Comparative Example 2 / / / / / / Comparative Example 3 17 5 0.38 45 66 589 Comparative Example 4 12 10 0.6 20 37 333 Comparative Example 5 31 11 0.9 34 47 421

[0079] Scanning electron microscope images of the sheet-like alumina used in Example 1 are as follows: Figure 1 and Figure 2 As shown, from Figure 1 and Figure 2 It can be seen that the average long side of the sheet-like alumina is about 20 μm, and the thickness is about 200 nm. The ratio of diameter to thickness is close to 100, which shows the morphological characteristics of a large diameter-to-thickness ratio and a smooth surface without obvious defects. Figure 3 This is a single-crystal diffraction photograph of the sheet-like alumina in Example 1. The single-crystal diffraction spot shows that the sheet-like alumina has a single-crystal structure. Figure 4 The image shown is a microscopic observation of the ABS thermoplastic engineering plastic of Example 1. When magnified 160 times, the distribution of flake-like alumina is visible, with uniform distribution in both the longitudinal and transverse directions.

[0080] Further performance tests were conducted on the engineering plastics of Examples 1-10 and Comparative Examples 1-5. The test structures are shown in Table 4. The tensile strength test method was GB / T 1040.4-2006; the flexural strength test method was GB / T 8812.2-2007; the melt flow rate test method was GB / T 3682.1-2018; the warping test method was GB 4677.5-84; the shrinkage test method was DIN 16901; and the cantilever beam impact strength test method was GB / T 1843-2008.

[0081] Table 4

[0082]

[0083]

[0084] As shown in Table 4, based on the performance test results of Examples 1-10 and Comparative Example 1, the unmodified pure ABS resin exhibits good toughness and resistance to bending and tensile stress. However, due to poor internal stress, its warping and dimensional stability in the TD and MD directions are relatively poor. Comparing Examples 1-10 with Comparative Examples 2-5, it is evident that filler modification can alter the internal stress of the resin and improve its dimensional stability. Compared to the commonly used ABS calcium carbonate composite film (Comparative Example 2), with an inorganic filler content of 20%, the warping is only 0.65%, failing to achieve ideal performance due to calcium carbonate agglomeration. In Example 1, adding 3 wt% flake alumina to the resin had no significant adverse effects on tensile strength, flexural strength, and melt flow rate. The addition of modified flake alumina significantly improved the shrinkage rate and warping, two important dimensional stability parameters, with the TD to MD ratio approaching 1:1. Although the mechanical properties of the product improved when the flake alumina content reached 10 parts in Example 5, the impact strength decreased. Considering both performance and cost, an optimal addition of 3-10 wt% flake alumina is recommended. The alumina used in Comparative Examples 3-5 had a smaller diameter-to-thickness ratio, resulting in limited bridging forces between the alumina and lipophilic groups, thus leading to a reduction in mechanical properties.

[0085] In summary, this embodiment uses pretreated nano-alumina as a functional filler to prepare ABS engineering plastic with dimensional stability. Using pretreated single-crystal α-phase nano-lamellar alumina can increase the MD and TD ratio to nearly 1. A very small amount can simultaneously improve cantilever impact strength, load deformation temperature, tensile strength, impact modulus, reduce deformation, and decrease flexural warping. This method is simple, inexpensive, and meets environmental requirements. Furthermore, the lamellar alumina can be uniformly distributed within the ABS resin. Utilizing the high hardness and high aspect ratio of nano-lamellar alumina, through targeted modification processes, the lamellar alumina can be uniformly dispersed and stacked during the thermoplasticization of ABS resin. The inherent properties and orientation of the lamellar alumina enhance the performance of the ABS plastic.

[0086] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0087] The products and preparation methods provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A thermoplastic engineering plastic, characterized in that, By weight percentage, it includes: 83-93% ABS resin, 3-10% flake alumina and 3-4% processing aids; The surface of the sheet-like alumina is connected with lipophilic groups.

2. The thermoplastic engineering plastic according to claim 1, characterized in that, The sheet-like alumina has a long side and a short side; the length of the long side is a μm, the length of the short side is b μm, and the thickness of the sheet-like alumina is c μm, satisfying: 50 < (a + b) / c < 225, and 500 < (a × b) / c 2 <8000.

3. The thermoplastic engineering plastic according to claim 1, characterized in that, The lipophilic group is selected from at least one of alkyl, aliphatic hydrocarbon, aromatic hydrocarbon, alkoxy, ester, and aliphatic ether groups.

4. The thermoplastic engineering plastic according to claim 2, characterized in that, The lamellar alumina further satisfies at least one of the following characteristics: 1) The plate-like alumina has an α-phase single-crystal structure; 2) The Mohs hardness of the sheet-like alumina is 8-10; 3) 40 ≤ a / c ≤ 120; 4)15≤a≤30； 5)5≤b≤15； 6)0.2≤c≤0.4。 5. The thermoplastic engineering plastic according to claim 1, characterized in that, The processing aid is selected from at least one of plasticizers, lubricants, and antioxidants.

6. A method for preparing the thermoplastic engineering plastic according to any one of claims 1-5, characterized in that, Includes the following steps: A flake-shaped alumina raw material, a surface modifier, and a catalyst are taken and reacted by heating and reflux to obtain flake-shaped alumina with lipophilic groups attached to its surface. A thermoplastic engineering plastic is obtained by mixing and extruding flake-shaped alumina with oleophilic groups attached to its surface, ABS resin, and processing aids.

7. The method for preparing the thermoplastic engineering plastic according to claim 6, characterized in that, The surface modifier is an isocyanate containing a lipophilic group; the lipophilic group is selected from at least one of alkyl, aliphatic hydrocarbon, aromatic hydrocarbon, alkoxy, ester, and aliphatic ether groups.

8. The method for preparing thermoplastic engineering plastic according to claim 7, characterized in that, The surface modifier is selected from at least one of methyl methyl isocyanate, benzyl isocyanate, p-chlorophenyl isocyanate, 2-benzyl isocyanate, phenyl isocyanate, ethyl isocyanate, chloroethyl isocyanate, 3-ethylphenyl isocyanate, butyrate isocyanate, and ethoxyisocyanate.

9. The method for preparing the thermoplastic engineering plastic according to claim 6, characterized in that, The mass ratio of the sheet-like alumina raw material, the surface modifier, and the catalyst is 20:(20-24):(1-2).

10. The method for preparing the thermoplastic engineering plastic according to claim 6, characterized in that, The heating temperature is 75-95℃, and the reflux reaction time is 0.5-3h.

Images