High-gloss spraying-free weather-resistant PMMA / ASA alloy material as well as preparation method and application thereof

Abstract

The invention discloses a high-gloss spraying-free weather-resistant PMMA / ASA alloy material as well as a preparation method and application thereof. The alloy material is prepared from various raw materials such as PMMA resin, ASA resin, purple B, AP blue, a compatilizer, an antioxidant and an ultraviolet light absorber. Wherein the purple B and the AP blue cooperate to form the high-quality spraying-free mirror surface highlight black powder, so that the material is endowed with high-gloss spraying-free characteristics; all the raw materials are matched with one another, so that the comprehensive performance of the alloy is improved, for example, the compatilizer enhances the compatibility of the resin, and the antioxidant and the ultraviolet light absorber improve the weather resistance. During preparation, part of the raw materials are premixed firstly, then processed by a twin-screw extruder at specific parameters such as temperature and rotating speed, and finally extruded, granulated and dried to obtain a finished product. Compared with the prior art, the alloy material is high in glossiness, excellent in weather resistance, good in comprehensive performance and simple and efficient in preparation process, and can be widely applied to the fields of automobile parts, electronic product shells, building decoration materials and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly to a high-gloss spray-free weather-resistant PMMA / ASA alloy material, its preparation method and application. Background Art

[0002] Alloy materials made of polymethyl methacrylate (PMMA) and acrylonitrile-styrene-acrylate copolymer (ASA) are widely used in fields such as automobiles and electronics. However, existing PMMA / ASA alloy materials have many problems.

[0003] In terms of gloss, the gloss of ordinary spray-free PMMA / ASA alloy materials is insufficient, making it difficult to meet the requirements for the appearance texture of high-end products. In automotive exterior applications, it cannot present a high-class gloss effect, affecting the overall aesthetics of the product. In terms of weather resistance, when existing alloy materials are exposed to harsh environments such as ultraviolet rays, high temperatures, and humidity for a long time, problems such as fading, color change, and embrittlement are likely to occur. For automotive parts used outdoors, after long-term exposure to sunlight and rain, the color will gradually fade, and the mechanical properties will decline, shortening the service life of the parts.

[0004] In addition, in the prior art, the development of PMMA / ASA alloy materials has mainly focused on the improvement of heat resistance and impact resistance. For example, Chinese Patent CN117777634A improves the Vicat softening temperature of the material by adding a methylacrylamide-modified heat-resistant masterbatch, but sacrifices the surface blackness; Chinese Patent CN118344699A uses an ABS / PMMA composite system to improve scratch resistance, but the gloss only reaches 83-93 GU, making it difficult to meet the requirements of high-end mirror surfaces; Chinese Patent CN119463394A introduces silicone to improve processing performance, but does not solve the problem of synergistic optimization of deep black tone and high gloss.

[0005] The disclosure of the above background art content is only used to assist in understanding the inventive concept and technical solution of the present invention, and it does not necessarily belong to the prior art of this patent application. Without clear evidence indicating that the above content was publicly available on the filing date of this patent application, the above background art should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0006] The present invention aims to solve the technical problems existing in the existing PMMA / ASA alloy material technology, and provides a high-gloss spray-free weather-resistant PMMA / ASA alloy material, its preparation method and application to meet the market demand for high-performance materials.

[0007] For the convenience of accurate understanding, the following are the accurate definitions of technical terms that will appear in the following text:

[0008] "PMMA" refers to: polymethyl methacrylate;

[0009] "ASA" refers to: acrylonitrile-styrene-acrylate copolymer;

[0010] "Purple B" refers to: Solvent Violet 13, which is an anthraquinone organic solvent dye;

[0011] "AP Blue" refers to: Solvent Blue 36, which is an anthraquinone organic solvent dye;

[0012] "SMA" refers to: styrene-maleic anhydride copolymer;

[0013] "MBS" refers to: methyl methacrylate-butadiene-styrene copolymer.

[0014] To this end, the present invention adopts the following technical solutions:

[0015] A high-gloss spray-free weather-resistant PMMA / ASA alloy material, comprising the following raw materials in parts by weight:

[0016] PMMA resin: 40 - 65 parts, ASA resin: 20 - 40 parts, Purple B: 0.1 - 0.5 parts, AP Blue: 0.05 - 0.3 parts, compatibilizer: 3 - 10 parts, antioxidant: 0.2 - 1.5 parts, ultraviolet absorber: 0.5 - 2.5 parts, lubricant: 0.3 - 1.2 parts, scratch-resistant agent 1 - 4 parts.

[0017] Preferably, the melt index of the PMMA resin is 5 - 20 g / 10 min, measured under the conditions of 230°C / 3.8 kg, and the acrylate rubber content of the ASA resin is 50 - 70 wt%.

[0018] Preferably, the compatibilizer is composed of SMA and MBS mixed in a weight ratio of 1:0.5 - 1:2.

[0019] Preferably, the antioxidant is composed of a hindered phenol antioxidant and a phosphite antioxidant mixed in a weight ratio of 1:0.8 - 1.2.

[0020] Preferably, the ultraviolet absorber is composed of 2-(2H-benzotriazol-2-yl)-4,6-ditert-amylphenol and a hindered amine light stabilizer mixed in a weight ratio of 3 - 5:1.

[0021] Preferably, the lubricant is composed of zinc stearate and polyethylene wax mixed in a weight ratio of 1 - 2:1 - 2.

[0022] Preferably, the scratch-resistant agent is a core-shell structure composite of polyester-modified silicone-coated nano-silica, wherein the molecular weight of the polyester-modified silicone is 4000-6000, the content of the polyester-modified silicone is 60-80 wt%, and the particle size of the nano-silica is 20-50 nm.

[0023] A preparation method of a high-gloss spray-free weather-resistant PMMA / ASA alloy material comprises the following steps:

[0024] S1. Premix PMMA resin, ASA resin, Violet B, AP Blue, and a compatibilizer to obtain a premix.

[0025] S2. Add the premix, an antioxidant, an ultraviolet absorber, a lubricant, and a scratch-resistant agent to a twin-screw extruder, control the temperature of the first zone at 180-190 °C, the temperature of the second to fourth zones at 200-230 °C, the temperature of the fifth to seventh zones at 220-240 °C, the die head temperature at 210-230 °C, the screw speed at 300-600 rpm, and the vacuum degree at -0.08 to -0.12 MPa.

[0026] S3. Dry after extrusion granulation to obtain the alloy material.

[0027] Preferably, the premixing time in step S1 is 5-15 min, and the mixing speed is 500-1000 rpm; the residence time of the material in the extruder in step S2 is 1.5-3 min, and the shear rate is 2000-4000 s -1 。

[0028] The present invention also provides an application of the high-gloss spray-free weather-resistant PMMA / ASA alloy material as described above in automotive parts, electronic product housings, or building decoration materials.

[0029] A high-gloss spray-free weather-resistant PMMA / ASA alloy material, its preparation method and application provided by the present invention significantly improve the performance of the material through the selection and synergistic effect of specific raw materials and process parameters. The following is an explanation from the perspectives of technical principles and parameter necessity:

[0030] Technical principles:

[0031] 1. The functions and synergistic effects of the raw materials of the alloy material:

[0032] PMMA resin and ASA resin: PMMA resin serves as the continuous phase, endowing the material with high light transmittance, surface hardness, and certain weather resistance. Its melt index of 5 - 20 g / 10min (measured under the conditions of 230°C / 3.8 kg) ensures appropriate fluidity during the processing, facilitating uniform mixing with other raw materials and molding, and avoiding molecular chain breakage under high shear. In ASA resin, the acrylate rubber phase acts as the dispersed phase, absorbing impact energy through a core-shell structure (rubber core + styrene-acrylonitrile shell), endowing it with excellent weather resistance, impact resistance, and good coloring properties. As the main matrix resins of the alloy, they provide the basic physical property framework for the material. The ester group structure (-COOCH3) of PMMA resin forms a hydrogen bond network with the acrylate in ASA, enhancing the interfacial bonding force; the nitrile group (-CN) in ASA resin forms a dipole-dipole interaction with the ester group of PMMA, inhibiting phase separation and increasing the impact strength; the properties of the two complement each other, laying the foundation for the comprehensive performance of the alloy material.

[0033] Violet B and AP Blue: Violet B (Solvent Violet 13) and AP Blue (Solvent Blue 36) are added as anthraquinone organic solvent dyes in a specific proportion. The conjugated double bonds (λmax = 580 nm) in the anthraquinone structure of Violet B form π-π stacking with the styrene unit of ASA, and are adsorbed on the surface of the rubber phase directionally, reducing light scattering. Its small molecular weight and high diffusion coefficient in the melt enable rapid and uniform dispersion. The amino group (-NH2) on the anthraquinone skeleton of AP Blue forms a hydrogen bond with the ester group of PMMA, inhibiting dye migration. When compounded with Violet B, the complementary absorption bands cover the entire spectrum of 400 - 700 nm, the reflectance drops below 5%, and the L value ≤ 5, with a significant synergistic effect. They cooperate with each other in the alloy system. The molecular structures of Violet B and AP Blue endow them with unique light absorption and reflection characteristics, enabling precise adjustment of the color and gloss of the material, forming a high-quality mirror-like high-gloss black powder effect without spraying, endowing the alloy material with a high-gloss appearance, and eliminating the need for the spraying process, simplifying the production process and reducing environmental pollution.

[0034] Compatibilizer: SMA contains polar maleic anhydride groups. The anhydride groups undergo an ester exchange reaction with the ester groups of PMMA to form a graft copolymer, reducing the interfacial tension. It can also interact with the polar groups in PMMA resin and ASA resin, enhancing the compatibility between different resins; MBS has a core-shell structure, and its rubber phase can toughen the alloy and improve the processing fluidity of the alloy at the same time. The two act synergistically, reducing the interfacial tension between PMMA resin and ASA resin, promoting the uniform dispersion and mutual fusion of the two resins, improving the mechanical properties and processing properties of the alloy, making the phases of the alloy combine more tightly, avoiding phase separation, and thus enhancing the overall performance.

[0035] Antioxidants: Hindered phenol antioxidants can capture free radicals generated during the oxidation of polymers, interrupt the oxidation chain reaction, and play a role in inhibiting oxidation; phosphite antioxidants mainly decompose hydroperoxides and convert them into stable compounds, thereby preventing the polymer from accelerating aging due to the accumulation of hydroperoxides. The combination of the two plays a role in different oxidation stages, jointly inhibiting the oxidation reaction of the alloy during processing and use, effectively extending the service life of the alloy material, and improving the stability of the material.

[0036] UV absorbers: 2-(2H-benzotriazol-2-yl)-4,6-ditert-amylphenol can strongly absorb ultraviolet light and convert it into heat energy and emit it, thereby protecting the polymer from ultraviolet damage; hindered amine light stabilizers effectively inhibit photooxidation reactions through various ways such as capturing free radicals, decomposing hydroperoxides, and quenching excited state molecules. The two work together to play a complementary role in absorbing ultraviolet light and inhibiting photooxidation, significantly improving the weather resistance of the alloy material, making it not prone to problems such as fading and aging during long-term use in outdoor environments.

[0037] Lubricants: Zinc stearate has good internal lubrication, which can reduce the friction between polymer molecular chains and improve the fluidity of the polymer; polyethylene wax has good external lubrication, which can form a lubricating film on the surface of the polymer and reduce the friction coefficient between the polymer and the processing equipment. The combination of the two improves the fluidity of the material during the alloy processing, facilitates the uniform dispersion and plasticization of the material in the twin-screw extruder, reduces the adhesion of the material to the equipment, improves production efficiency, and at the same time makes the surface of the product smoother and improves the appearance quality of the product.

[0038] Scratch-resistant agents: Polyester-modified silicone has good wear resistance and smoothness characteristics, and can form a protective film with certain elasticity and lubricity on the surface of the alloy; nano-silica has a small particle size and high hardness, and is evenly dispersed in the polyester-modified silicone, enhancing the hardness and wear resistance of the composite structure. This core-shell structure composite as a scratch-resistant agent is evenly dispersed in the alloy material, which can effectively improve the surface hardness and scratch resistance of the alloy, making the alloy material not prone to scratches during use and maintaining a good appearance.

[0039] 2. Technical effects of the selection of process parameters for each step of the preparation process:

[0040] Pre-mixing step (S1): Premix PMMA resin, ASA resin, Violet B, AP Blue, and compatibilizer. Control the mixing time within 5 - 15 min and the mixing speed at 500 - 1000 rpm. Appropriate mixing time and speed ensure the initial uniform dispersion of these raw materials, bringing each component closer to each other at the microscopic level, creating good conditions for further mixing and reaction in the twin-screw extruder. Shorter mixing time and too low speed may lead to uneven mixing of raw materials, affecting the performance consistency of the final alloy material; while too long mixing time and too high speed may cause degradation or agglomeration of some raw materials, also having an adverse impact on performance.

[0041] Twin-screw extruder processing step (S2): Add the premix, antioxidant, ultraviolet absorber, lubricant, and scratch-resistant agent into the twin-screw extruder, and precisely control the temperature of each zone, screw speed, vacuum degree, residence time of the material, and shear rate.

[0042] Temperature control: Set the temperature of the first zone at 180 - 190 °C. This temperature is slightly lower than the melting points of PMMA resin and ASA resin. The main purpose is to preliminarily soften the material, avoid premature melting of ASA, and facilitate the subsequent conveying and mixing by the screw. The temperature of the second to fourth zones is 200 - 230 °C to achieve two-phase melt blending; the temperature of the fifth to seventh zones is 220 - 240 °C to promote the transesterification reaction of SMA. These temperature ranges fully melt PMMA resin and ASA resin, while promoting the uniform mixing and interaction of each additive with the resin. At this gradient temperature, the compatibilizer can better diffuse to the interface of the two resins, enhancing compatibility; the antioxidant and ultraviolet absorber can be evenly dispersed in the resin matrix, playing their stabilizing and protective roles. The die temperature is 210 - 230 °C, ensuring that the extruded material has good fluidity for easy molding and guaranteeing the surface quality of the product.

[0043] Screw speed, vacuum degree, residence time, and shear rate: The screw speed is 300 - 600 rpm, providing sufficient shear force and conveying capacity to fully mix and plasticize the material in the extruder. Appropriate screw speed can ensure the uniform dispersion of each raw material in the molten state, avoiding local concentration unevenness. The vacuum degree is controlled at -0.08 to -0.12 MPa, which can effectively remove moisture, volatiles, and small molecule gases generated during the mixing process in the material, preventing defects such as bubbles and silver streaks in the product, and improving the quality and performance of the product. The residence time of the material in the extruder is 1.5 - 3 min, ensuring that each raw material has enough time for physical mixing and chemical reaction to form a stable alloy structure. The shear rate is 2000 - 4000 s-1. Within this range, it can not only fully mix and plasticize the material but also prevent the polymer molecular chain from breaking due to excessive shear force, affecting the performance of the material.

[0044] Drying step (S3) after extrusion granulation: After extrusion granulation, drying is carried out to remove the moisture absorbed by the material during processing and the residual volatile substances. The drying treatment can improve the stability of the alloy material and avoid affecting the performance of the product due to the presence of moisture or volatiles during subsequent forming processing or use, such as reducing the mechanical properties of the product and causing surface defects.

[0045] The technical advantages of the present invention compared with the prior art are as follows:

[0046] 1. High gloss and paint-free performance advantages: The gloss of existing ordinary paint-free PMMA / ASA alloy materials is difficult to meet the requirements of high-end products. Usually, an additional spraying process is required to improve the appearance effect, which not only increases costs but also causes environmental pollution. By precisely controlling the addition amounts of Violet B and AP Blue and utilizing their unique optical properties, the present invention achieves a paint-free high gloss effect. This high gloss is achieved through the synergistic effect of the two dyes at the molecular level, which can accurately adjust the reflection and absorption of light by the material, forming a high-quality mirror-like high gloss effect, providing a more textured appearance for the product, having significant application advantages in fields such as automotive parts and electronic product casings, and enhancing the market competitiveness of the product.

[0047] 2. Improvement in excellent weather resistance: Traditional PMMA / ASA alloy materials have deficiencies in weather resistance. When exposed to harsh environments such as ultraviolet rays, high temperature, and humidity for a long time, problems such as fading, aging, and performance degradation are likely to occur. The present invention uses 2-(2H-benzotriazol-2-yl)-4,6-ditert-amylphenol and a hindered amine light stabilizer compounded in a specific ratio as an ultraviolet absorber, which synergistically acts with an antioxidant to construct a multi-level protection system. The ultraviolet absorber effectively absorbs ultraviolet rays and inhibits the photo-oxidation reaction, while the antioxidant prevents the oxidation and aging of the material during processing and use. This synergistic protection mechanism significantly improves the weather resistance of the alloy material, enabling it to maintain good color stability, mechanical properties, and appearance quality during long-term outdoor use, greatly extending the service life of the product, reducing maintenance and replacement costs, and having important application value in fields such as building decoration materials and automotive parts used outdoors.

[0048] 3. Good comprehensive performance optimization: In the prior art, it is often difficult for PMMA / ASA alloy materials to balance multiple properties simultaneously. For example, increasing hardness may reduce impact resistance, and improving weather resistance may affect processing performance. In the present invention, through careful screening and design of the raw material formula, the synergistic effect between various raw materials realizes the optimization of comprehensive performance. The compatibilizer enhances the compatibility between PMMA resin and ASA resin, improving the mechanical properties of the alloy; the unique core-shell structure design of the scratch-resistant agent significantly enhances the surface hardness and scratch resistance of the material; the lubricant improves the processing performance, making the material more smooth during processing and simultaneously enhancing the surface quality of the product. This optimization of comprehensive performance enables the alloy material of the present invention to exhibit excellent performance in multiple fields, meet the diverse needs of different application scenarios, and broaden the application scope of the material. When applied to the production of automotive parts, the performance of the relevant automotive parts reaches: density 1.12 - 1.17 g / cm 3 , melt flow rate ≥ 6 g / 10 min, flexural strength ≥ 65 Mpa, flexural modulus ≥ 2000 Mpa, tensile strength ≥ 45 Mpa, impact strength ≥ 8 kJ / m 2 , blackness L value ≤ 5, color difference △E of samples for each total irradiation amount ≤ 3.0, and there should be no obvious changes on the surface of the test pieces, especially changes in color or gloss, and no deformation, shrinkage, etc. (total irradiation amount ≥ 1240.8 KJ / m 2 ).

[0049] 4. Advantages of efficient preparation process: In terms of the preparation process, the method of the present invention has significant advantages. Precise control of parameters such as the pre-mixing time, mixing speed, and the temperature, screw speed, vacuum degree, material residence time, and shear rate of the twin-screw extruder ensures the full mixing, uniform dispersion, and stable reaction of various raw materials. Compared with some complex existing preparation processes, the process parameters of the present invention are easy to control, the operation is simple, and large-scale industrial production can be achieved. Moreover, through the optimization of these parameters, the production efficiency is effectively improved, the energy consumption and scrap rate during the production process are reduced, the production cost is lowered, the economic benefits of the enterprise are increased, and the price competitiveness of the product in the market is enhanced. Detailed implementation mode

[0050] The features and technical advantages of the present invention have been broadly described above so as to better understand the detailed description of the present invention. Other features and advantages of the present invention will be described below. Those skilled in the art should understand that the disclosed concepts and specific embodiments can be easily used as a basis to modify or design other structures to achieve the same purpose of the present invention. Those skilled in the art should also recognize that such equivalent configurations do not deviate from the spirit and scope of the present invention. The novel features considered to be the characteristics of the present invention, its structural and operational methods, as well as further purposes and advantages. However, it should be deeply understood that each feature provided is only for description and illustration, and is not intended to limit the definition of the present invention.

[0051] In an embodiment of the specific implementation manner of the present invention, the high-gloss spray-free weather-resistant PMMA / ASA alloy material includes the following raw materials in parts by weight:

[0052] PMMA resin: 40 - 65 parts, ASA resin: 20 - 40 parts, Violet B: 0.1 - 0.5 part, AP Blue: 0.05 - 0.3 part, compatibilizer: 3 - 10 parts, antioxidant: 0.2 - 1.5 parts, ultraviolet absorber: 0.5 - 2.5 parts, lubricant: 0.3 - 1.2 parts, scratch-resistant agent: 1 - 4 parts.

[0053] The melt index of the PMMA resin is 5 - 20 g / 10 min, measured under the conditions of 230 °C / 3.8 kg, and the acrylate rubber content of the ASA resin is 50 - 70 wt%.

[0054] The compatibilizer is composed of SMA and MBS mixed in a weight ratio of 1:0.5 - 1:2.

[0055] The antioxidant is composed of a hindered phenol antioxidant and a phosphite antioxidant mixed in a weight ratio of 1:0.8 - 1.2.

[0056] The ultraviolet absorber is composed of 2-(2H-benzotriazol-2-yl)-4,6-ditert-amylphenol and a hindered amine light stabilizer mixed in a weight ratio of 3 - 5:1.

[0057] The lubricant is composed of zinc stearate and polyethylene wax mixed in a weight ratio of 1 - 2:1 - 2.

[0058] The scratch-resistant agent is a core-shell structure composite of polyester-modified silicone-coated nano-silica, wherein the molecular weight of the polyester-modified silicone is 4000 - 6000, the content of the polyester-modified silicone is 60 - 80 wt%, and the particle size of the nano-silica is 20 - 50 nm.

[0059] The preparation method of the high-gloss spray-free weather-resistant PMMA / ASA alloy material includes the following steps:

[0060] S1. Premixing PMMA resin, ASA resin, purple B, AP blue and compatibilizer to obtain a premix;

[0061] S2. The premix, antioxidant, UV absorber, lubricant and scratch resistant agent are added to a twin-screw extruder, and the temperature of zone 1 is controlled at 180-190°C, the temperature of zones 2 to 4 at 200-230°C, the temperature of zones 5 to 7 at 220-240°C, the die temperature at 210-230°C, the screw speed at 300-600rpm, and the vacuum degree at -0.08 to -0.12MPa;

[0062] S3. After extrusion granulation, drying is performed to obtain an alloy material.

[0063] The premixing time in step S1 is 5-15 minutes, and the mixing speed is 500-1000 rpm; the residence time of the material in the extruder in step S2 is 1.5-3 minutes, and the shear rate is 2000-4000s -1 .

[0064] Examples 1-5

[0065] A high-gloss spray-free weather-resistant PMMA / ASA alloy material, comprising the following raw materials:

[0066] PMMA resin, ASA resin, purple B, AP blue, compatibilizer, antioxidant, ultraviolet absorber, lubricant, anti-scratch agent. The specific weight parts of raw materials are shown in Table 1.

[0067] The melt index of the PMMA resin is 12 g / 10 min, measured at 230° C. / 3.8 kg, and the acrylate rubber content of the ASA resin is 60 wt %.

[0068] The compatibilizer is composed of SMA and MBS mixed in a weight ratio of 1:1.

[0069] The antioxidant is a mixture of a hindered phenol antioxidant and a phosphite antioxidant in a weight ratio of 1:1.

[0070] The ultraviolet absorber is composed of 2-(2H-benzotriazole-2-yl)-4,6-di-tert-amylphenol and a hindered amine light stabilizer mixed in a weight ratio of 4:1.

[0071] The lubricant is a mixture of zinc stearate and polyethylene wax in a weight ratio of 1:1.

[0072] The scratch-resistant agent is a core-shell structure composite of polyester-modified organic silicon coated with nano-silicon dioxide, wherein the molecular weight of the polyester-modified organic silicon is 5000, the content of the polyester-modified organic silicon is 70wt%, and the particle size of the nano-silicon dioxide is 35nm.

[0073] Table 1 Numerical values of the weight parts of the raw materials of the alloy materials described in Examples 1-5

[0074] Raw material components Example 1 Example 2 Example 3 Example 4 Example 5 PMMA resin 50 55 60 45 65 ASA resin 30 25 20 35 25 Violet B 0.3 0.2 0.4 0.1 0.5 AP Blue 0.2 0.3 0.1 0.3 0.05 Compatibilizer 5 4 6 3 8 Antioxidant 0.5 0.4 0.6 0.4 0.2 Ultraviolet absorber 1.2 1.0 1.5 0.5 2.0 Lubricant 0.6 0.5 0.8 0.3 1.0 Scratch resistance agent 3 2 3 1 4

[0075] The preparation method of the alloy materials described in Examples 1-5 includes the following steps:

[0076] S1. Premix PMMA resin, ASA resin, Violet B, AP Blue, and compatibilizer. The premixing time is 10 min and the mixing speed is 800 rpm; obtain the premixed material;

[0077] S2. Add the premixed material, antioxidant, ultraviolet absorber, lubricant, and scratch-resistant agent to a twin-screw extruder. Control the temperature of zone 1 at 185°C, the temperatures of zones 2-4 at 215°C, the temperatures of zones 5-7 at 230°C, the die head temperature at 220°C, the screw speed at 500 rpm, and the vacuum degree at -0.1 MPa; the residence time of the material in the extruder is 2 min, and the shear rate is 3000 s -1 ;

[0078] S3. After extrusion granulation, dry to obtain the alloy material.

[0079] Comparative Example 1

[0080] A high-gloss spray-free weather-resistant PMMA / ASA alloy material, the difference in the raw material composition from that of Example 5 is that the compatibilizer is replaced with PMMA resin of equal weight; the preparation method is the same as that of Example 5.

[0081] Comparative Example 2

[0082] A high-gloss spray-free weather-resistant PMMA / ASA alloy material, the difference in the raw material composition from that of Example 5 is that the antioxidant is replaced with PMMA resin of equal weight; the preparation method is the same as that of Example 5.

[0083] Comparative Example 3

[0084] A high-gloss spray-free weather-resistant PMMA / ASA alloy material, the difference in the raw material composition from that of Example 5 is that the ultraviolet absorber is replaced with PMMA resin of equal weight; the preparation method is the same as that of Example 5.

[0085] Comparative Example 4

[0086] A high-gloss spray-free weather-resistant PMMA / ASA alloy material, the difference in the raw material composition from that of Example 5 is that the lubricant is replaced with PMMA resin of equal weight; the preparation method is the same as that of Example 5.

[0087] Comparative Example 5

[0088] A high-gloss spray-free weather-resistant PMMA / ASA alloy material, the difference in the raw material composition from that of Example 5 is that the scratch-resistant agent is replaced with PMMA resin of equal weight; the preparation method is the same as that of Example 5.

[0089] Performance index detection tests were carried out on the alloy materials prepared in Examples 1-5 and Comparative Examples 1-5. The specific detection items and methods are as follows:

[0090] 1. Density: The pycnometer method was used and tested according to the standard of GB / T1033.1-2008. The prepared alloy material was made into a regular specimen and placed in a pycnometer, and its mass in a liquid with a known density was measured, and the material density was calculated through calculation.

[0091] 2. Melt flow rate: A melt flow rate instrument was used and tested according to the standard of GB / T3682.1-2018 at 230 °C and a load of 3.8 kg. Record the mass of the extruded material within 10 min, and the unit is g / 10 min.

[0092] 3. Bending strength and bending modulus: According to the standard of GB / T9341-2008, the three-point bending method was adopted. The specimen was processed into a size of 80 mm × 10 mm × 4 mm and tested on a universal material testing machine. The span was 64 mm and the bending speed was 2 mm / min. Record the force and displacement data during the bending process, and calculate the bending strength and bending modulus.

[0093] 4. Tensile strength: According to the standard of GB / T1040.2-2006, the specimen was made into a dumbbell shape and tensile tested on a universal material testing machine at a tensile speed of 50 mm / min. Record the maximum force during the tensile process and calculate the tensile strength.

[0094] 5. Impact strength: According to the standard of GB / T1043.1-2008, the simply supported beam notched impact test was adopted. The specimen was processed into a size of 80 mm × 10 mm × 4 mm, with an A-type notch opened, and a 4J pendulum was used for impact testing. Record the energy at the time of impact failure, and the unit is kJ / m 2 .

[0095] 6. Blackness L value: A spectrophotometer was used and tested according to the standard of GB / T7921-2008. The surface of the specimen was polished flat, and the blackness L value under a specific light source was measured. The smaller the L value, the greater the blackness.

[0096] 7. Color difference △E and surface change: The specimen was exposed to an environment with a total irradiation dose ≥ 1240.8 KJ / m 2 . The color difference △E before and after irradiation was measured using a color difference meter, and at the same time, whether there were obvious changes on the surface of the specimen was observed, including color, gloss, deformation, shrinkage, etc.

[0097] The results of the detection tests for the above performance indicators are shown in Table 2.

[0098] Table 2 Results of the Detection Tests for the Performance Indicators of the Alloy Materials Prepared in Examples 1-5

[0099]

[0100] Note: "-" indicates not detected.

[0101] As can be seen from Table 2 above, the densities of Examples 1-5 are all in the range of 1.12-1.17 g / cm 3 This is because the densities of PMMA resin and ASA resin themselves are similar, and the dosages of other additives are relatively small, having little impact on the overall density. Although fine-tuning of the raw material ratios in different examples will cause small changes in density, they are still within the specified range, indicating that the formulation design is reasonable, the mixing uniformity among raw materials is good, and no obvious phase separation or abnormal density occurs.

[0102] The melt flow rate of all examples is ≥6 g / 10 min. This benefits from the melt index range of PMMA resin and the function of the lubricant. The lubricant reduces the friction between polymer molecular chains and the friction coefficient between the polymer and processing equipment, making the material have good fluidity during processing. The melt index of PMMA resin affects the melt fluidity, and an increase in its content usually increases the melt flow rate. For example, in Example 5, the content of PMMA resin is the highest, and the melt flow rate is also the largest. At the same time, it also shows that the interaction among raw materials does not have an adverse effect on melt flow, ensuring the forming performance of the material during processing.

[0103] PMMA resin and ASA resin provide basic rigidity, and the compatibilizer enhances the compatibility between the two resins, making the internal structure of the material more uniform and compact, and improving the ability to resist bending deformation. The nano-silica in the scratch-resistant agent also plays a reinforcing role. It is evenly dispersed in the resin matrix, hindering the expansion of cracks during bending, thereby improving the bending strength and bending modulus. Judging from the data, as the content of ASA resin increases, such as in Example 5, the bending performance is improved, indicating that ASA resin plays a positive role in enhancing the rigidity of the material.

[0104] The molecular structures of PMMA resin and ASA resin endow the material with certain tensile properties. The addition of antioxidants and ultraviolet absorbers stabilizes the molecular structure of the material, reduces the breakage of molecular chains during processing and use, and helps to maintain the tensile strength. The compatibilizer enhances the interfacial bonding force between different phases, enabling the material to better transmit stress during the stretching process and improving the tensile strength. The relatively high contents of PMMA resin and ASA resin in Example 5, along with the synergistic effect of various additives, result in the highest tensile strength. This further demonstrates the important influence of the matrix resin content on the tensile properties.

[0105] The acrylate rubber phase in ASA resin can absorb energy when subjected to impact, playing a toughening role. As part of the compatibilizer, the rubber phase of MBS also helps to improve the impact toughness of the material. The core-shell structure composite of the scratch-resistant agent can also disperse the impact energy to a certain extent, preventing the generation and propagation of cracks. With the increase in the content of ASA resin and MBS, the proportion of related raw materials such as ASA resin in Example 5 makes the synergistic effect optimal in enhancing the impact resistance performance.

[0106] Purple B and AP Blue are added in a specific ratio and are evenly dispersed in the alloy system. Their light absorption and reflection characteristics make the material exhibit high blackness. By precisely controlling the dosages of the two dyes, the ideal blackness effect is achieved, meeting the requirements for the appearance color of automotive parts. The relatively high contents of Purple B and AP Blue in Example 2 result in a blackness L value of 4.2, indicating that appropriately increasing the dye dosage helps to further improve the blackness. At the same time, the differences among different examples illustrate the importance of precisely controlling the dye dosage for the blackness.

[0107] Under the condition that the total irradiation dose ≥ 1240.8 KJ / m 2 , the color difference △E of the specimens for each total irradiation dose is ≤ 3.0, and there are no obvious changes on the surface of the specimens. This benefits from the synergistic effect of antioxidants and ultraviolet absorbers, which effectively inhibit the photo-oxidation reaction and the aging degradation of the material, protecting the molecular structure and color stability of the material. The protective film formed by the scratch-resistant agent on the surface also helps to reduce the influence of irradiation on the surface, preventing color and gloss changes as well as deformation, shrinkage, etc.

[0108] From the experimental data of Comparative Examples 1-5, it can be seen that the mechanical property indexes such as flexural strength, flexural modulus, and tensile strength of Comparative Example 1 (without compatibilizer) decreased significantly compared with those of the Examples. For example, the flexural strength dropped to 65.2 MPa, the flexural modulus decreased to 2100 MPa, and the tensile strength decreased to 47.0 MPa. This is because the absence of the compatibilizer led to a decrease in the compatibility between PMMA and ASA resins, a weakening of the interfacial bonding force, and phase separation, making the internal structure of the material uneven and unable to effectively resist external forces. The color difference △E of Comparative Example 2 (without antioxidant) increased significantly, reaching 3.5, indicating that after the absence of the antioxidant, the material was more prone to oxidation under irradiation, the color stability became worse, and the weather resistance deteriorated. The color difference △E of Comparative Example 3 (without ultraviolet absorber) was even higher, reaching 4.2, and fading and cracks appeared on the surface, indicating that the ultraviolet absorber was crucial for resisting photooxidation, and without it, the material could not protect its molecular structure and color. The melt flow rate of Comparative Example 4 (without lubricant) decreased significantly to 11.8 g / 10 min, indicating that the lubricant was indispensable for improving the processing fluidity and surface quality. Multiple mechanical properties of Comparative Example 5 (without scratch-resistant agent) decreased, and the impact strength decreased to 8.6 kJ / m 2 , showing the key role of the scratch-resistant agent in improving the surface durability of the material.

[0109] Through the analysis of the performance test data of the alloy materials in Examples 1-5, it can be seen that the performance indexes of the alloy materials prepared by the present invention all meet the production requirements. The change in the proportion of different raw materials has a significant impact on the material performance, and there is a synergistic effect among the raw materials. PMMA resin and ASA resin, as the matrix resins, lay the basic performance of the material; additives such as compatibilizer, antioxidant, ultraviolet absorber, lubricant, and scratch-resistant agent play key roles in enhancing compatibility, stabilizing the molecular structure, improving the processing performance, and improving scratch resistance and weather resistance, respectively. The experiments of Comparative Examples 1-5 fully verify the synergism and necessity among the additives in the formula design of the present invention. The lack of any additive will cause a significant deterioration in the corresponding performance of the material. The formula design and preparation process of the present invention are reasonable and feasible, and the produced alloy materials have excellent performance and are applicable to fields such as automotive parts, electronic product casings, and building decoration materials.

[0110] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several alternatives or modifications can be made to these described embodiments, and these alternative or modification methods should all be regarded as belonging to the protection scope of the present invention.

Claims

1. A high-gloss spray-free weather-resistant PMMA / ASA alloy material, characterized in that, Comprising the following raw materials in parts by weight: PMMA resin: 40 - 65 parts, ASA resin: 20 - 40 parts, Violet B: 0.1 - 0.5 parts, AP Blue: 0.05 - 0.3 parts, compatibilizer: 3 - 10 parts, antioxidant: 0.2 - 1.5 parts, ultraviolet absorber: 0.5 - 2.5 parts, lubricant: 0.3 - 1.2 parts, scratch resistance agent: 1 - 4 parts.

2. A high-gloss spray-free weather-resistant PMMA / ASA alloy material according to claim 1, characterized in that, The melt index of the PMMA resin is 5 - 20 g / 10 min, measured under the conditions of 230°C / 3.8 kg, and the acrylate rubber content of the ASA resin is 50 - 70 wt%.

3. A high-gloss spray-free weather-resistant PMMA / ASA alloy material according to claim 1, characterized in that, The compatibilizer is composed of SMA and MBS mixed in a weight ratio of 1:0.5 - 1:

2.

4. A high-gloss spray-free weather-resistant PMMA / ASA alloy material according to claim 1, characterized in that, The antioxidant is composed of a hindered phenol antioxidant and a phosphite antioxidant mixed in a weight ratio of 1:0.8 - 1.

2.

5. A high-gloss spray-free weather-resistant PMMA / ASA alloy material according to claim 1, characterized in that, The ultraviolet absorber is composed of 2-(2H-benzotriazol-2-yl)-4,6-ditert-amylphenol and a hindered amine light stabilizer mixed in a weight ratio of 3 - 5:

1.

6. A high-gloss spray-free weather-resistant PMMA / ASA alloy material according to claim 1, characterized in that The lubricant is composed of zinc stearate and polyethylene wax mixed in a weight ratio of 1 - 2:1 - 2.

7. A high-gloss spray-free weather-resistant PMMA / ASA alloy material according to claim 1, characterized in that, The scratch resistance agent is a core-shell structure composite of polyester-modified silicone-coated nano-silica, wherein the molecular weight of the polyester-modified silicone is 4000 - 6000, the content of the polyester-modified silicone is 60 - 80 wt%, and the particle size of the nano-silica is 20 - 50 nm.

8. A method for preparing a high-gloss spray-free weather-resistant PMMA / ASA alloy material according to any one of claims 1 - 7, comprising the following steps: S1. Premix the PMMA resin, ASA resin, Violet B, AP Blue, and compatibilizer to obtain a premix. S2. Add the premix, antioxidant, ultraviolet absorber, lubricant, and scratch resistance agent to a twin-screw extruder, control the temperature of zone 1 at 180 - 190°C, the temperature of zones 2 - 4 at 200 - 230°C, the temperature of zones 5 - 7 at 220 - 240°C, the die head temperature at 210 - 230°C, the screw speed at 300 - 600 rpm, and the vacuum degree at -0.08 to -0.12 MPa. S3. Dry after extrusion granulation to obtain the alloy material.

9. The preparation method of a high-gloss spray-free weather-resistant PMMA / ASA alloy material according to claim 8, characterized in that, In the step S1, the pre-mixing time is 5 - 15 min and the mixing rotation speed is 500 - 1000 rpm; in the step S2, the residence time of the material in the extruder is 1.5 - 3 min and the shear rate is 2000 - 4000 s -1 .

10. An application of a high-gloss spray-free weather-resistant PMMA / ASA alloy material produced by the method according to any one of claims 8 - 9 in automotive parts, electronic product housings, or building decoration materials.

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