Inorganic nano polymer water-based film and preparation method thereof

Abstract

The invention discloses an inorganic nano high-molecular water-based film and a preparation method, and relates to the field of nano materials, the inorganic nano high-molecular water-based film comprises fumed silica, silicon nitride, a leveling agent, an inorganic pigment filler and a functional auxiliary agent according to a specific mass percentage, the preparation method comprises the steps of raw material pretreatment, asymmetric gradient feeding, multi-mode dispersion grinding, gradient nitrogen replacement, performance verification, subpackaging and the like, the raw materials are optimized through plasma activation and low-temperature calcination, uniform mixing of components is promoted through asymmetric gradient feeding, and nano-scale particle size uniform dispersion is achieved through multi-mode dispersion grinding. The gas environment is effectively controlled through gradient nitrogen displacement, and the oxidation resistance and stability of the water-based film are improved. Compared with the prior art, the invention has the advantages of excellent performance stability, remarkably improved performance index and good oxidation resistance and stability; the cable has the advantages of high temperature resistance, low temperature resistance, strong acid and strong alkali resistance, wear resistance, compression resistance, static dissipation, antimagnetic sterilization, fire prevention, flame retardance and full-band infrared self-adaptive environment stealth.

Description

Technical Field

[0001] The present invention relates to chemical anti-corrosion coatings, high and low temperature resistance, acid and alkali resistance, thermal insulation and flame retardancy, wear resistance and pressure resistance, static dissipation, anti-magnetic and anti-nuclear radiation, intelligent materials, etc., including national defense and military industry, marine engineering and shipbuilding, petrochemical industry, fire safety, cultural relics protection, civilian fields, etc. It specifically refers to an inorganic nano-polymer water-based film and a preparation method. Background Art

[0002] As a new type of functional material, inorganic nanopolymer waterborne membranes combine the advantages of inorganic nanomaterials and polymer materials, exhibiting excellent mechanical properties, thermal stability, chemical stability, electromagnetic stability, and other unique functional properties, such as optical and electromagnetic properties. In the architectural decoration field, inorganic nanopolymer waterborne membranes can be used for the decoration and protection of walls, floors, and other surfaces. Their high hardness and wear resistance effectively resist the scratches and abrasions of daily use. Their excellent weather resistance ensures long-term outdoor use without fading or cracking. In the electronic packaging field, this material can be used to encapsulate electronic components, and its excellent insulation and thermal conductivity properties can improve the reliability and heat dissipation efficiency of electronic equipment. In the aerospace field, inorganic nanopolymer waterborne membranes are used for surface protection of aircraft, satellites, and other aircraft. Their lightweight and high strength characteristics help reduce the weight of aircraft, while their high temperature and radiation resistance adapt to extreme operating environments.

[0003] At present, there are some patents published in the field of inorganic nano-polymer water-based membranes. For example, the patent with publication number CN107936725A discloses a water-based laser film material, which is mainly prepared by simply mixing inorganic nanoparticles with polymers. However, this simple mixing method has the following shortcomings: (1) Uneven distribution of components: Due to the poor compatibility between inorganic nanoparticles and polymers, agglomeration is likely to occur during the mixing process, resulting in uneven distribution of components, which in turn affects the performance stability and consistency of the water-based membrane; (2) Simple and rough preparation process: The preparation process adopted in this patent is relatively simple, lacking fine control of key links such as raw material pretreatment and dispersion grinding. In terms of raw material pretreatment, the inorganic nanoparticles are not effectively surface modified, resulting in weak interfacial bonding between them and the polymer, affecting the mechanical properties of the water-based membrane.

[0004] For example, patent publication number CN103703036B proposes a monolayer membrane and a hydrophilic material including the monolayer membrane, and improves the dispersibility of inorganic nanoparticles by adding a dispersant. However, this method still has the following problems: (1) Limited dispersion effect: Although the addition of a dispersant can improve the dispersibility of inorganic nanoparticles to a certain extent, the effect of the dispersant is limited for some nanoparticles with high specific surface area and easy to agglomerate; (2) The influence of gases during the preparation process is not considered: During the preparation process, gases such as oxygen in the environment may react with the components of the aqueous membrane, affecting its performance. Summary of the Invention

[0005] In response to the above-mentioned problems existing in the prior art, the present invention aims to provide an inorganic nano-polymer water-based membrane and its preparation method to solve the following problems: (1) Improving the uniformity of component distribution: By optimizing the component formula and improving the preparation process, inorganic nanoparticles such as fumed silica and silicon nitride are made compatible and uniformly distributed with the polymer matrix. By forming a hexagonal dome structure and using multivariate linear and nonlinear models to determine the variable coefficients, the performance stability, scientificity and consistency of the water-based membrane are improved. (2) Achieving uniform dispersion of nano-scale particles: Using a multimodal dispersion grinding process, combining grinding beads of different specifications and different grinding parameters, the raw materials are finely ground to achieve uniform dispersion of nano-scale particles, give full play to the nano-effect of inorganic nanoparticles, and improve the mechanical properties and optical properties of the water-based membrane. (3) Effectively controlling the gas environment during the preparation process: Through a gradient nitrogen replacement process, different nitrogen replacement methods are used at different stages to effectively remove harmful gases such as oxygen during the preparation process, reduce the reaction probability of the water-based membrane with gas, and improve its oxidation resistance and stability.

[0006] Specifically, the technical solution provided by the present invention is: an inorganic nano-polymer water-based film, comprising the following components in percentage by weight: 25.8%-34.8% fumed silica, 27.8%-35.8% silicon nitride, 4%-8% leveling agent, 21.4%-29.4% inorganic pigment and filler, and 4%-9% functional auxiliary agent;

[0007] The preparation method of the inorganic nano-polymer aqueous membrane includes the following steps: S1, raw material pretreatment; S2, asymmetric gradient feeding; S3, multimodal dispersion grinding; S4, gradient nitrogen replacement; S5, performance verification and packaging.

[0008] Furthermore, the composition includes the following components in percentage by mass: 27.8%-32.8% of fumed silica, 29.8%-33.8% of silicon nitride, 5-7% of a leveling agent, 23.4%-27.4% of an inorganic pigment and filler, and 5-8% of a functional auxiliary agent.

[0009] Furthermore, the components include the following mass percentages: 30.8% fumed silica, 31.8% silicon nitride, 6% leveling agent, 25.4% pure inorganic pigments and fillers, and 7% functional auxiliary agents. This ratio varies greatly in products with different uses.

[0010] Furthermore, S1 also includes: S1.1, plasma activation of fumed silica, using a DBD plasma processor, power setting 380W±20W; argon / oxygen mixture ratio 4:1, gas flow rate 15SLM; processing time 105s±15s, electrode spacing 6mm; surface energy after treatment reaches above 72.5mN / m; S1.2, low-temperature calcination of silicon nitride, from room temperature to 120°C and holding for 30 minutes, then to 280°C and holding for 60 minutes, then to 400°C and holding for 120 minutes; nitrogen protection flow rate 8L / min, furnace pressure slightly positive pressure 0.02Mpa; cooling to below 80°C, discharging, and sealed storage;

[0011] Furthermore, S2 also includes: S2.1, preparation of continuous phase, first add 70% of the base material, D50 = 800nm, then add all the leveling agent, maintain the temperature at 45℃±1℃, stir at 800rpm, and pre-disperse for 30min; S2.2, preparation of dispersed phase: the remaining 30% of the base material is mixed with the functional auxiliary agent, D50 = 150nm, 0.1% of the silane coupling agent is added, the temperature is controlled at 30℃±1℃, and ultrasonic treatment is performed at 40kHz / 300W and maintained for 15min.

[0012] Furthermore, S3 also includes: S3.1, primary dispersion, transferring the two-phase material into a basket grinder, Φ1.0mm zirconium oxide grinding beads with a filling rate of 65%, a linear speed of 8m / s, a temperature ≤35℃, a time of 30min, and a 5-min interval to detect the fineness ≤50μm; S3.2, precision grinding, replacing the composite grinding beads, the composite grinding beads have a specification of ZrO2 / Si3N4=7:3, Φ0.3mm, the linear speed is increased to 15m / s, the temperature is controlled at 40℃±1℃, the vacuum degree is -0.08Mpa and maintained for 60min; sampling is taken every 15min to detect the particle size distribution to ensure that D90≤800nm; S3.3, nano-level fine grinding, using Φ0.1mm pure silicon nitride grinding beads, a linear speed of 22m / s, a temperature of 45-48℃, a high vacuum of -0.095Mpa and a holding time of 90min, and the final fineness D100≤200nm.

[0013] Furthermore, S4 also includes: S4.1, normal pressure replacement stage, nitrogen purity ≥99.999%, dew point ≤-70℃, flow rate 20L / min and holding time 30min, synchronous stirring speed 400rpm; S4.2, pulse pressurization replacement, pressure 0.3MPa, pulse frequency 0.5Hz, flow rate reduced to 8L / min, time 45min, temperature maintained at 45℃±2℃; S4.3, negative pressure and high temperature replacement, the system is evacuated to -0.08Mpa, nitrogen is preheated to 60℃±2℃, replacement time is 60min, and the final oxygen content is ≤50ppm.

[0014] Furthermore, S5 also includes: S5.1, online detection, 25℃ viscosity test meets 1500-1800cP at 25℃, fineness test meets scraper fineness meter ≤5μm; pH value 8.5-9.0; S5.2, packaging process, nitrogen protection packaging, residual oxygen ≤0.5%, use special packaging barrels with oxygen content indicator, storage temperature 10-30℃, keep away from light.

[0015] The advantages of the present invention over the prior art are: (1) Excellent performance stability: Due to the uniform distribution of components and uniform dispersion of nano-scale particles, the inorganic nano-polymer water-based membrane prepared by the present invention has excellent performance stability. Under different environmental conditions, its hardness, wear resistance, optical properties and other indicators can remain stable, meeting the strict requirements of high-end application fields for material performance; (2) Significantly improved performance indicators: Through a sophisticated preparation process, the present invention achieves a good combination of inorganic nanoparticles and polymer matrix, fully exerts the nano effect, and significantly improves the mechanical properties and optical properties of the water-based membrane, with higher hardness, better wear resistance and more excellent optical transmittance, which can meet some application scenarios with extremely high performance requirements; (3) Good oxidation resistance and stability: The gradient nitrogen replacement process effectively controls the gas environment during the preparation process, reduces the reaction probability of the water-based membrane with oxygen, and improves its oxidation resistance and stability. During long-term storage and use, the water-based membrane of the present invention is not easily oxidized and deteriorated, can maintain good performance, and extend the service life of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is a flow chart of a method for preparing an inorganic nano-polymer water-based membrane. DETAILED DESCRIPTION

[0017] Example 1

[0018] like Figure 1As shown, this embodiment provides an inorganic nano-polymer water-based film, including the following components in mass percentage: 25.8%-34.8% of fumed silica, 27.8%-35.8% of silicon nitride, 4-8% of leveling agent, 21.4%-29.4% of inorganic pigments and fillers, and 4-9% of functional auxiliary agents.

[0019] Further preferred component mass percentages are: fumed silica 27.8%-32.8%, silicon nitride 29.8%-

[0020] 33.8%, leveling agent 5-7%, inorganic pigments and fillers 23.4%-27.4%, functional auxiliary agents 5-8%. A further preferred component weight percentage is: 30.8% fumed silica, 31.8% silicon nitride, 6% leveling agent, 25.4% pure inorganic pigments and fillers, and 7% functional auxiliary agents.

[0021] Accordingly, a method for preparing an inorganic nanopolymer aqueous film comprises the following steps:

[0022] S1. Raw material pretreatment

[0023] S1.1. Plasma Activation of Fumed Silica: A DBD plasma processor was used, with a power setting of 380W ± 20W, an argon / oxygen mixture ratio of 4:1, a gas flow rate of 15 SLM, a treatment time of 105s ± 15s, and an electrode spacing of 6mm. The surface energy after treatment reached over 72.5 mN / m. Plasma activation of the fumed silica introduces active groups onto its surface, improving its interfacial bonding with the polymer matrix and promoting uniform distribution of the components.

[0024] S1.2. Low-temperature calcination of silicon nitride: Heat from room temperature to 120°C and hold for 30 minutes, then to 280°C and hold for 60 minutes, then to 400°C and hold for 120 minutes. Use a nitrogen protection flow rate of 8 L / min and a slightly positive pressure of 0.02 MPa in the furnace. Cool to below 80°C, discharge, and seal for storage. Low-temperature calcination removes impurities and moisture from the silicon nitride surface, improves its surface properties, and enhances its compatibility with the polymer matrix.

[0025] S2, asymmetric gradient feeding

[0026] S2.1. Preparation of the continuous phase: First, add 70% of the base material (D50 = 800 nm), then add all the leveling agent. Maintain the temperature at 45°C ± 1°C, stir at 800 rpm, and pre-disperse for 30 minutes. Preparing the continuous phase first provides a stable matrix environment for the subsequent addition of the dispersed phase, facilitating uniform mixing of the components.

[0027] S2.2, Dispersed Phase Preparation: Mix the remaining 30% base material with the functional additive to a D50 of 150 nm. Add 0.1% silane coupling agent. Control the temperature at 30°C ± 1°C and ultrasonicate at 40 kHz / 300 W for 15 minutes. Using a finer particle size and ultrasonication in the dispersed phase preparation facilitates uniform dispersion of the functional additive in the base material, improving the performance of the waterborne membrane.

[0028] S3, Multimodal Dispersion Grinding

[0029] S3.1. Primary Dispersion: Transfer the two-phase materials into a basket mill with a 65% fill rate of 1.0 mm zirconia grinding beads, a linear speed of 8 m / s, a temperature ≤ 35°C, a grinding time of 30 minutes, and a 5-minute interval to check for a fineness of ≤ 50 μm. Use larger-sized grinding beads for primary dispersion to quickly reduce the particle size and improve dispersion efficiency.

[0030] S3.2 Precision Grinding: Replace composite grinding beads with ZrO2 / Si3N4 = 7:3, Φ0.3mm, and increase the linear speed to 15m / s. Maintain the temperature at 40°C ± 1°C and the vacuum at -0.08MPa for 60 minutes. Samples are taken every 15 minutes to test the particle size distribution, ensuring D90 ≤ 800nm. Precision grinding uses composite grinding beads and a higher linear speed to further refine the material particle size and improve dispersion uniformity.

[0031] S3.3, Nano-level Fine Grinding: Use Φ0.1mm pure silicon nitride grinding beads, a linear speed of 22m / s, a temperature of 45-48°C, a high vacuum of -0.095MPa for 90 minutes, and a final fineness of D100 ≤ 200nm. Nano-level fine grinding uses extremely fine grinding beads and a high vacuum environment to achieve uniform dispersion of nano-scale particles and fully utilize the nano-effect.

[0032] S4, gradient nitrogen replacement

[0033] S4.1. Atmospheric pressure displacement stage: Nitrogen purity ≥ 99.999%, dew point ≤ -70°C, flow rate 20 L / min for 30 minutes, simultaneous stirring speed 400 rpm. High-purity nitrogen is used during the atmospheric pressure displacement stage to rapidly displace most of the air in the reaction system.

[0034] S4.2, Pulse pressure displacement: Pressure 0.3 MPa, pulse frequency 0.5 Hz, flow rate reduced to 8 L / min, duration 45 minutes, temperature maintained at 45°C ± 2°C. Pulse pressure displacement further removes residual air through pressure changes, improving the displacement effect.

[0035] S4.3, Negative Pressure, High-Temperature Replacement: Evacuate the system to -0.08 MPa, preheat nitrogen to 60°C ± 2°C, and perform a 60-minute replacement. The final oxygen content should be ≤ 50 ppm. Negative Pressure, High-Temperature Replacement thoroughly removes harmful gases such as oxygen under high temperature and negative pressure conditions, ensuring the oxidation resistance and stability of the waterborne membrane.

[0036] S5. Performance Verification and Repackaging

[0037] S5.1. Online testing: Viscosity testing at 25°C must meet the requirements of 1500-1800 cP, fineness testing must meet the requirements of a scraper fineness meter of ≤5 μm, and pH value must be 8.5-9.0. Through online testing, the performance indicators of water-based membranes are monitored in real time to ensure that product quality meets requirements.

[0038] S5.2. Packaging: Nitrogen-filled packaging, residual oxygen ≤ 0.5%, using dedicated packaging barrels with oxygen indicator. Store at 10-30°C in the dark. Nitrogen-filled packaging and dedicated packaging barrels further prevent the water-based membrane from coming into contact with oxygen during storage, ensuring long-term product stability.

[0039] Example 2

[0040] like Figure 1 As shown, this embodiment provides an inorganic nanopolymer water-based membrane. Essentially, it is a single-component inorganic polymer copolymer. It boasts the advantages of high technology, pollution-free operation, multifunctionality, asset-lightness, low cost, and wide application. It is suitable for use in defense and military industries, marine engineering, petrochemicals, consumer appliances, road transportation, building materials and decoration, and other fields. The material can sustainably withstand temperatures ranging from -196°C to 2300°C. It can be used as a primer or topcoat in atmospheric environments and is suitable for use on properly treated carbon steel, aluminum alloy, stainless steel, cement, and ceramic substrates. It can withstand temperatures up to 1600°C and intermittently up to 2300°C. It can be used on hot substrates up to 250°C and is applicable to a variety of metal surfaces and firebrick surfaces, providing long-term corrosion protection. It is suitable for use in corrosion protection projects for the interior and exterior walls of most chemical liquid pipelines and gas and liquid storage tanks, demonstrating exceptionally strong resistance to high temperatures, corrosion, and aging. It maintains its corrosion resistance for extended periods in environments with strong ultraviolet rays, high salt spray, and chlorine corrosion, and resists fading. The product specifications for this product vary depending on the product type and model. The main product varieties include: facial mask, middle mask, base mask. The main product models include: colorless water-based membrane material, red water-based membrane material, yellow-blue-green water-based membrane material. The performance parameters of the products are shown in Table 1:

[0041]

[0042]

[0043] Table 1 Product performance parameters

[0044] Example 3

[0045] like Figure 1 As shown, this embodiment provides a specific implementation method of the surface treatment of this material, and its treatment standards are as follows

[0046] As shown in Table 2:

[0047]

[0048] Table 2 Surface treatment standards

[0049] This product can be applied to surfaces using the following methods: (1) Spray: Use air spray. (2) Brush: Recommended for pre-coating and small area coating to achieve a specified dry film thickness. Airless spraying guidance parameters: Nozzle diameter (mm): 1.0mm; Nozzle pressure (minimum): 150 bar / 2100 psi.

[0050] The drying and curing time of this product is determined based on temperature and relative humidity. The relative humidity is less than 60% and the dry film thickness is within the average dry film thickness range. Surface (touch) dry: The state where there is no fingerprint residue or no adhesion when lightly pressed with a finger. Walk-on dry: The shortest time in which the coating can be walked on normally without leaving permanent footprints, marks or other physical damage. Details are shown in Table 3:

[0051]

[0052] Table 3 Drying and curing time comparison table

[0053] Heat resistance of this product:

[0054] (1) Continuous temperature

[0055] Dry, 1200℃ in atmospheric environment.

[0056] (2) Substrate

[0057] Continuous: 1200°C, Peak: 2000C.

[0058] At temperatures above this level, the protective performance is not affected, but the aesthetics may be affected.

[0059] In terms of product compatibility, this product can be used with different primers and topcoats according to different actual exposure conditions during use:

[0060] (1) Previous coating: epoxy resin, itself;

[0061] (2) Next coating: Self-storage

[0062] This product should be stored in accordance with national regulations in a dry, cool, well-ventilated environment away from heat and ignition sources. Keep the container tightly closed and handle with care. Do not exceed a storage temperature of 30°C. The inorganic polymer copolymer anti-corrosion coating has a shelf life of three months at 15°C. In some markets, the listed shelf life may be shortened to comply with local regulations. This is the minimum shelf life and subsequent testing is required to confirm quality.

[0063] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. An inorganic nanopolymer water-based membrane, characterized in that The invention comprises the following components in percentage by mass: 25.8%-34.8% of fumed silica, 27.8%-35.8% of silicon nitride, 4%-8% of a leveling agent, 21.4%-29.4% of an inorganic pigment and filler, and 4%-9% of a functional auxiliary agent; The preparation method of the inorganic nano-polymer aqueous membrane includes the following steps: S1, raw material pretreatment; S2, asymmetric gradient feeding; S3, multimodal dispersion grinding; S4, gradient nitrogen replacement; S5, performance verification and packaging.

2. An inorganic nano-polymer aqueous film according to claim 1, characterized in that: The invention comprises the following components in percentage by mass: 27.8%-32.8% of fumed silicon dioxide, 29.8%-33.8% of silicon nitride, 5-7% of a leveling agent, 23.4%-27.4% of an inorganic pigment and filler, and 5-8% of a functional auxiliary agent.

3. An inorganic nano-polymer aqueous film according to claim 2, characterized in that: The invention comprises the following components in percentage by mass: 30.8% of fumed silica, 31.8% of silicon nitride, 6% of a leveling agent, 25.4% of a pure inorganic pigment and filler, and 7% of a functional auxiliary agent.

4. A method for preparing an inorganic nanopolymer aqueous film according to claim 1, characterized in that The S1 also includes: S1.

1. Plasma activation of fumed silica using a DBD plasma processor with a power setting of 380W ± 20W, an argon / oxygen mixture ratio of 4:1, a gas flow rate of 15 SLM, a treatment time of 105s ± 15s, and an electrode spacing of 6mm. The surface energy after treatment reached over 72.5mN / m. S1.

2. Calcinate silicon nitride at low temperature from room temperature to 120°C and maintain for 30 minutes, then to 280°C and maintain for 60 minutes, then to 400°C and maintain for 120 minutes; nitrogen protection flow rate 8L / min, furnace pressure slightly positive pressure 0.02Mpa; cool to below 80°C, discharge, and seal for storage.

5. A method for preparing an inorganic nanopolymer aqueous film according to claim 1, characterized in that S2 also includes: S2.1, continuous phase preparation, first adding 70% base material, D50 = 800nm, then adding all the leveling agent, maintaining the temperature at 45℃±1℃, stirring at 800rpm, and pre-dispersing for 30min; S2.

2. Preparation of dispersed phase: the remaining 30% base material was mixed with the functional auxiliary agent, D50 = 150nm, 0.1% silane coupling agent was added, the temperature was controlled at 30°C ± 1°C, and ultrasonic treatment was performed at 40kHz / 300W for 15 minutes.

6. A method for preparing an inorganic nanopolymer aqueous film according to claim 1, characterized in that S3 also includes: S3.

1. Primary dispersion: transfer the two-phase materials into a basket mill with a filling rate of 65% using Φ1.0 mm zirconium oxide grinding beads, a linear speed of 8 m / s, a temperature ≤ 35°C, a time of 30 min, and a fineness check every 5 min to ≤ 50 μm. S3.2, precision grinding, replace composite grinding beads, composite grinding beads with specifications of ZrO2 / Si3N4=7:3, Φ0.3mm, increase linear speed to 15m / s, control temperature at 40℃±1℃, vacuum degree -0.08Mpa and maintain for 60min; sample every 15min to test particle size distribution, ensure D90≤800nm; S3.3, nano-level fine grinding, use Φ0.1mm pure silicon nitride grinding beads, linear speed 22m / s, temperature 45-48℃, high vacuum -0.095Mpa and hold time 90min, final fineness D100≤200nm.

7. A method for preparing an inorganic nanopolymer aqueous film according to claim 1, characterized in that The S4 also includes: S4.

1. At atmospheric pressure replacement stage, nitrogen purity ≥ 99.999%, dew point ≤ -70°C, flow rate 20 L / min and hold time 30 min, synchronous stirring speed 400 rpm; S4.

2. Pulse pressure displacement, pressure 0.3 MPa, pulse frequency 0.5 Hz, flow rate reduced to 8 L / min, time 45 min, temperature maintained at 45°C ± 2°C; S4.

3. Negative pressure and high temperature replacement: evacuate the system to -0.08 MPa, preheat nitrogen to 60°C ± 2°C, replace for 60 minutes, and the final oxygen content is ≤50 ppm.

8. A method for preparing an inorganic nano-polymer aqueous film according to claim 1, characterized in that The S5 also includes: S5.1, online testing, 25 ℃ viscosity test 25 ℃ meet 1500-1800 cP, fineness test meet scraper fineness meter ≤ 5μm; pH value 8.5-9.0; S5.

2. Repackaging process: nitrogen-filled packaging, residual oxygen ≤ 0.5%, use special packaging barrels with oxygen content indicator, storage temperature 10-30℃, keep away from light.

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