Polymer composite material for catalytic degradation of formaldehyde and preparation method thereof

Abstract

The application relates to the technical field of building, in particular to a high-molecular composite material for catalytic degradation of formaldehyde and a preparation method thereof, which comprises the following steps: determining the adding amount of a stabilizer based on the melt flow rate and the oxidation induction period of random copolymerized polypropylene, and modifying the stabilizer to obtain a first intermediate product; determining the preset feeding proportion of the first intermediate product based on the oxidation induction period of the first intermediate product; heating and blending raw materials in a screw extruder to obtain a second intermediate product, determining a mixed state characteristic value based on the density and the agglomeration index of the metal oxide, and determining whether the mixed state of the second intermediate product meets the standard, and checking the mixed state when the mixed state does not meet the standard; adjusting the screw rotation speed of the screw extruder based on the melt color uniformity feedback of the second intermediate product; and cooling and forming the second intermediate product after extrusion to obtain a product. The application solves the problem that the uneven dispersion of nanoscale metal oxide particles leads to the local degradation of formaldehyde.

Description

Technical Field

[0001] This invention relates to the field of building technology, and in particular to a polymeric composite material for catalytic degradation of formaldehyde and its preparation method. Background Technology

[0002] The widespread use of modern building and decoration materials has led to indoor air pollution. Formaldehyde mainly comes from artificial boards, paints, adhesives, etc., and its release period can be as long as 3 to 15 years. Therefore, the development of functional materials that can continuously and effectively degrade indoor formaldehyde has great social and economic value.

[0003] However, this technical approach faces several core challenges. Nanoscale metal oxide particles have high surface energy, making them prone to agglomeration during polymer melt mixing, forming macroscopic aggregates. This leads to a reduction in active sites and a significant decrease in catalytic efficiency. Furthermore, traditional composite material preparation process parameters are typically fixed once set. The lack of real-time monitoring and feedback control of key indicators during mixing results in large fluctuations in product quality and unstable catalytic performance. Therefore, there is an urgent need in this field for a process-controllable, low-cost method to stably produce high-efficiency polymer composite materials for the catalytic degradation of formaldehyde.

[0004] Chinese Patent Publication No. CN106696380A discloses a photodegradable formaldehyde film, in which a dispersion of nano-sized metal oxide particles Ag-TiO2 is added to the hard coating of automotive films, building films, and home films in a certain manner, ensuring the original performance of the product without changing the hardness, scratch resistance, transmittance, etc. of the original film hard coating, while adding the function of degrading formaldehyde.

[0005] Therefore, it can be seen that the invention is prone to uneven dispersion of nano-sized metal oxide particles during polymer melt mixing, which leads to the failure of the local formaldehyde degradation function. Summary of the Invention

[0006] Therefore, the present invention provides a polymeric composite material for catalytic degradation of formaldehyde and its preparation method, in order to overcome the problems in the prior art where uneven dispersion of nanoscale metal oxide particles leads to local failure of formaldehyde degradation function and large batch-to-batch product quality fluctuations.

[0007] To achieve the above objectives, in one aspect, the present invention provides a method for preparing a polymer composite material for catalytic degradation of formaldehyde, comprising:

[0008] Step S1: Determine the amount of stabilizer to be added based on the melt flow rate and oxidation induction period of random copolymer polypropylene, and add stabilizer to the melt random copolymer polypropylene to modify it in order to obtain the first intermediate product.

[0009] Step S2: Based on the relative deviation between the oxidation induction period of the first intermediate product and the preset target oxidation induction period, determine the preset dosage ratio of the first intermediate product and adjust it accordingly.

[0010] Step S3: The first intermediate product is heated and blended with PVC particles, nano-sized metal oxide particles, adhesive, and foaming agent in a screw extruder to obtain the second intermediate product.

[0011] Step S4: Determine the mixing state characteristic value based on the density of the second intermediate product and the aggregation index of the nanoscale metal oxide particles to determine whether the mixing state of the second intermediate product meets the standard, and verify the mixing state based on the density of the second intermediate product when the mixing state does not meet the standard.

[0012] Step S5: In response to verifying the mixing state, the screw speed of the screw extruder is adjusted based on the melt color uniformity feedback of the second intermediate product, wherein the melt color uniformity is negatively correlated with the dispersion state of the nanoscale metal oxide particles in the matrix.

[0013] Step S6: The second intermediate product is extruded and cooled to form a polymer composite material product.

[0014] Further, step S1 includes:

[0015] Step S11: Premix random copolymer polypropylene, antioxidant and compatibilizer at 80°C for 8 min;

[0016] Step S12: Obtain the melt flow rate and oxidation induction period of the random copolymer polypropylene;

[0017] Step S13: Based on the result that the oxidation induction period is less than a preset oxidation induction period threshold and the melt flow rate is less than a preset melt flow rate threshold, determine to add a stabilizer;

[0018] Step S14: Determine the amount of stabilizer to be added based on the sum of the ratio of the oxidation induction period to the preset oxidation induction period threshold multiplied by a first weighting coefficient and the ratio of the melt flow rate to the melt flow rate threshold multiplied by a second weighting coefficient, so as to obtain the first intermediate product.

[0019] Further, step S2 includes:

[0020] Step S21: Obtain the oxidation induction period of the first intermediate product;

[0021] Step S22: Determine the performance difference value based on the difference between the oxidation induction period of the first intermediate product and the preset oxidation induction period threshold.

[0022] Step S23: Determine the relative deviation based on the ratio of the performance difference value to the preset oxidation induction period threshold. The relative deviation is used to quantify the degree of difference between the oxidation induction period of the first intermediate product and the preset oxidation induction period threshold.

[0023] Step S24: Determine the intermediate product dosage ratio based on the product of the relative deviation and the preset dosage ratio of the first intermediate product.

[0024] Further, in step S4, the method for determining the characteristic value of the mixed state includes:

[0025] Step S41: Detect density values ​​in the feeding section, compression section, and metering section of the screw extruder, calculate the average density value, and normalize the average density value.

[0026] Step S42: Obtain the D90 and D10 particle sizes of the nanoscale metal oxide particles, and determine the aggregation index based on the ratio of the D90 particle size to the D10 particle size.

[0027] Step S43: Based on the product of the normalized average density value and the first adjustment coefficient, the product of the aggregation index and the second adjustment coefficient is summed to determine the mixed state characteristic value.

[0028] Furthermore, step S4 also includes:

[0029] Step S44: Compare and analyze the mixed state feature value with the first preset mixed state feature threshold and the second preset mixed state feature threshold;

[0030] Step S45: Based on the result that the mixing state characteristic value is less than the first preset mixing state characteristic threshold, it is determined that the mixing state of the second intermediate product does not meet the preset standard and the mixing temperature is increased; based on the result that the mixing state characteristic value is greater than or equal to the first preset mixing state characteristic threshold and less than the second preset mixing state characteristic threshold, it is determined that the mixing state of the second intermediate product is verified; based on the result that the mixing state characteristic value is greater than or equal to the second preset mixing state characteristic threshold, it is determined that the mixing state meets the preset standard.

[0031] The increase in the mixing temperature is positively correlated with the ratio of the mixing state characteristic value to the first preset mixing state characteristic threshold.

[0032] The first preset mixed state feature threshold is determined based on the lower limit of the mixed state feature value in the historical qualified batches, and the second preset mixed state feature threshold is determined based on the median of the mixed state feature value in the historical qualified batches.

[0033] Furthermore, the mixing state of the second intermediate product is verified, including:

[0034] Based on the result that the density of the second intermediate product is less than the preset density, it is determined that the mixing state of the second intermediate product meets the preset standard. Based on the result that the density of the second intermediate product is greater than or equal to the preset density, it is determined that the mass ratio of the foaming agent should be increased.

[0035] The increase in the proportion of the foaming agent is positively correlated with the difference between the density of the second intermediate product and the preset density.

[0036] Further, in step S5, adjusting the screw speed of the screw extruder based on the melt color uniformity feedback of the second intermediate product includes:

[0037] Step S51: Collect the color parameters of the second intermediate product and obtain its brightness value;

[0038] Step S52: Determine the color deviation value based on the difference between the brightness value and the preset color uniformity qualification threshold;

[0039] Step S53: The product of the ratio of the color deviation value to the preset color uniformity qualification threshold and the preset screw speed determines the screw speed adjustment value.

[0040] Furthermore, in step S5, the screw speed is determined based on the sum of the preset screw speed and the screw speed adjustment value.

[0041] Furthermore, after increasing the screw speed, the mixing temperature is adjusted according to the adjustment range of the screw speed, thereby reducing the mixing temperature. The reduction range of the mixing temperature is directly related to the reduction range of the screw speed.

[0042] Furthermore, the preset mass ratio of the polymer composite material is 10 parts PVC particles, 15 parts random copolymer polypropylene, 2 parts nano-sized metal oxide particles, 0.1 parts adhesive, 0.1 parts foaming agent, 0.2 parts antioxidant, and 0.5 parts compatibilizer.

[0043] The preset mass ratio of the nanoscale metal oxide particles is 1 part titanium dioxide and 1 part copper oxide.

[0044] Compared with the prior art, the beneficial effects of the present invention are that by obtaining the mixing state characteristic value of the second intermediate product in real time and dynamically adjusting the mixing temperature accordingly, the aggregation of nanoparticles can be effectively broken, promoting their uniform dispersion at the nanoscale in the polymer matrix, maximizing the exposure of the active sites of the catalyst, and resulting in the final product having extremely high and stable formaldehyde catalytic degradation efficiency. Compared with the traditional method of fixing process parameters, the formaldehyde absorption rate of the material produced by the present invention can be increased by more than 20%, and the batch-to-batch difference is small.

[0045] Furthermore, by using the density of the mixture as a key control indicator, when the density is abnormally high, the system automatically adjusts the proportion of the foaming agent to precisely control the foaming process. This not only ensures that the material achieves the ideal lightweight goal, but more importantly, the uniform microporous structure formed greatly increases the specific surface area of ​​the material, providing more contact and reaction channels for formaldehyde gas and the internally embedded catalyst particles, realizing bulk degradation rather than just surface degradation, and greatly improving the degradation capacity and long-term effectiveness of the material.

[0046] Furthermore, by linking the performance indicators of the final product with key process parameters, a closed-loop optimization system is formed, enabling the production process to have the ability to learn and optimize itself. Even if there are slight fluctuations in raw materials, the system can ensure the consistency of the final product performance by fine-tuning the process parameters, which greatly improves the production yield and quality stability, laying a solid foundation for large-scale industrial application.

[0047] Furthermore, a composite of titanium dioxide and copper oxide is preferred as the catalytic system. Titanium dioxide has good photocatalytic activity, while copper oxide has good catalytic oxidation performance at room temperature. The combination of the two can produce a synergistic effect, effectively degrading formaldehyde under indoor visible light or even dark conditions. This avoids the use of expensive precious metal catalysts, greatly reducing raw material costs while ensuring efficient degradation, making the product significantly competitive in the market.

[0048] Furthermore, the shear heat generated by increasing the rotation speed can compensate for the reduced temperature. While ensuring the mixing effect, it avoids energy waste and thermal degradation of the polymer matrix caused by overheating, thus achieving energy saving and consumption reduction, extending the service life of the equipment, and protecting the mechanical properties of the polymer material, making the product both functional and durable. Attached Figure Description

[0049] Figure 1 This is a flowchart illustrating the preparation method of the polymer composite material for catalytic degradation of formaldehyde according to an embodiment of the present invention;

[0050] Figure 2 This is a flowchart of step S1 in the preparation method of the polymer composite material for catalytic degradation of formaldehyde according to an embodiment of the present invention;

[0051] Figure 3 This is a logic diagram of step S4 in the preparation method of the polymer composite material for catalytic degradation of formaldehyde according to an embodiment of the present invention;

[0052] Figure 4 This is a flowchart of step S5 in the preparation method of the polymer composite material for catalytic degradation of formaldehyde according to an embodiment of the present invention. Detailed Implementation

[0053] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0054] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the invention.

[0055] Please see Figure 1 The figures shown are flowcharts of the preparation method of the polymer composite material for catalytic degradation of formaldehyde according to embodiments of the present invention.

[0056] The method for preparing a polymer composite material for catalytic degradation of formaldehyde according to embodiments of the present invention includes:

[0057] Step S1: Determine the amount of stabilizer to be added based on the melt flow rate and oxidation induction period of random copolymer polypropylene, and add stabilizer to the melt random copolymer polypropylene to modify it in order to obtain the first intermediate product.

[0058] Step S2: Based on the relative deviation between the oxidation induction period of the first intermediate product and the preset target oxidation induction period, determine the preset dosage ratio of the first intermediate product and adjust it accordingly.

[0059] Step S3: The first intermediate product is heated and blended with PVC particles, nano-sized metal oxide particles, adhesive, and foaming agent in a screw extruder to obtain the second intermediate product.

[0060] Step S4: Determine the characteristic value of the mixing state based on the density of the second intermediate product and the aggregation index of the nanoscale metal oxide particles, so as to determine whether the mixing state of the second intermediate product meets the standard, and verify the mixing state based on the density of the second intermediate product when the mixing state does not meet the standard.

[0061] Step S5: In response to verifying the mixing state, the screw speed of the screw extruder is adjusted based on the melt color uniformity feedback of the second intermediate product, wherein the melt color uniformity is negatively correlated with the dispersion state of the nanoscale metal oxide particles in the matrix.

[0062] Step S6: The second intermediate product is extruded and cooled to form a polymer composite material product.

[0063] Please see Figure 2 The diagram shows a flowchart of step S1 in the preparation method of the polymer composite material for catalytic degradation of formaldehyde according to an embodiment of the present invention. Step S1 includes:

[0064] Step S11: Add random copolymer polypropylene, antioxidant and compatibilizer into a high-speed mixer, heat the mixer and maintain it at 80°C, mix at 300 rpm for 8 minutes to allow the additives to be initially dispersed and coated on the surface of the random copolymer polypropylene particles.

[0065] Step S12: Take a sample from the premix and, in accordance with GB / T 17391-2011 standard, test its oxidation induction period at 190°C in an oxygen atmosphere using a differential scanning calorimeter.

[0066] Step S13: Based on the results that the oxidation induction period is less than 20 min and the melt flow rate is less than 3.0 g / 10 min, determine the addition of a stabilizer;

[0067] Step S14: The amount of stabilizer to be added is determined based on the sum of the ratio of the oxidation induction period to the preset oxidation induction period threshold multiplied by a first weighting coefficient and the ratio of the melt flow rate to the melt flow rate threshold multiplied by a second weighting coefficient, in order to obtain the first intermediate product. The specific calculation method is as follows:

[0068] m=[(T / T0)×k1+(V / V0)×k2]×m0

[0069] Where m is the amount of stabilizer added, T0 is the preset oxidation induction period threshold, preferably 20 min, T is the current oxidation induction period, k1 is the first weighting coefficient, preferably 0.42, V is the measured melt flow rate, V0 is the melt flow rate threshold, preferably 3.0 g / 10 min, k2 is the second weighting coefficient, preferably 0.58, and m0 is the preset amount of stabilizer added, preferably 3 parts.

[0070] Understandably, based on industry experience and subsequent processing temperatures, random copolymer polypropylene with an oxidation induction period of 20 minutes or more is considered to have sufficient thermal stability to withstand subsequent extrusion processing without severe degradation.

[0071] In this embodiment, the first weighting coefficient k1 and the second weighting coefficient k2 are dimensionless coefficients. Their values ​​are determined based on the balance between the thermal stability and processing fluidity of the material during the extrusion process, and are the optimal values ​​determined in combination with the principles of materials science. These values ​​can effectively balance the influence of the oxidation induction period and the melt flow rate on the thermal stability of the material.

[0072] Specifically, step S2 includes:

[0073] Step S21: Obtain the oxidation induction period of the first intermediate product;

[0074] Step S22: Determine the performance difference value based on the difference between the oxidation induction period of the first intermediate product and the preset oxidation induction period threshold.

[0075] Step S23: Determine the relative deviation based on the ratio of the performance difference value to the preset oxidation induction period threshold. The relative deviation is used to quantify the degree of difference between the oxidation induction period of the first intermediate product and the preset oxidation induction period threshold.

[0076] Step S24: Determine the first intermediate product dosage ratio based on the product of the relative deviation and the preset dosage ratio of the first intermediate product;

[0077] The specific calculation method is as follows:

[0078] C = (T - T0) / T0 × C0

[0079] Where C is the proportion of intermediate product added, C0 is the preset proportion of the first intermediate product added, T is the current oxidation induction period, and T0 is the preset oxidation induction period threshold.

[0080] Please see Figure 3 The diagram shown is a logic diagram of step S4 in the preparation method of the polymer composite material for catalytic degradation of formaldehyde according to an embodiment of the present invention. In step S4, the method for determining the characteristic value of the mixed state includes:

[0081] Step S41: Detect density values ​​in the feeding section, compression section, and metering section of the screw extruder, calculate the average density value, and normalize the average density value.

[0082] The density of the second intermediate product was measured using an online density meter in the feeding section, compression section, and metering section of the twin-screw extruder, and denoted as ρ1, ρ2, and ρ3, respectively. The average density was:

[0083] ρavg = (ρ1 + ρ2 + ρ3) / 3

[0084] To eliminate dimensions, the average density value is normalized:

[0085] ρ=ρavg / ρmax

[0086] Where ρmax is the mass-weighted average density of each component, calculated using the following formula:

[0087] ρmax = Σ(component mass fraction × component theoretical density)

[0088] In this embodiment, ρmax is taken as 1.45 g / cm³;

[0089] Step S42: Obtain the D90 and D10 particle sizes of the nanoscale metal oxide particles, and determine the aggregation index based on the ratio of the D90 particle size to the D10 particle size.

[0090] A=D90 / D10

[0091] Where A represents the reunion index;

[0092] Step S43: Determine the mixed state characteristic value based on the sum of the product of the normalized average density value and the first adjustment coefficient and the product of the aggregation index and the second adjustment coefficient;

[0093] M = u1 × ρ + u2 × A

[0094] Where M is the characteristic value of the mixed state, u1 is the first adjustment coefficient, preferably 0.32, and u2 is the second adjustment coefficient, preferably 0.41. In this embodiment, the first adjustment coefficient u1 and the second adjustment coefficient u2 are dimensionless coefficients. Their values ​​are determined based on various combinations of adjustment coefficients tested during the production process of five batches. The formaldehyde absorption rate of each batch was recorded. It was found that when u1=0.32 and u2=0.41, the average formaldehyde absorption rate of the product reached 98.2%, which is the optimal value, and the difference between batches is small.

[0095] Step S44: Compare and analyze the mixed state feature value with the first preset mixed state feature threshold and the second preset mixed state feature threshold;

[0096] Step S45: Based on the result that the mixing state characteristic value is less than the first preset mixing state characteristic threshold, it is determined that the mixing state of the second intermediate product does not meet the preset standard and the mixing temperature is increased; based on the result that the mixing state characteristic value is greater than or equal to the first preset mixing state characteristic threshold and less than the second preset mixing state characteristic threshold, it is determined that the mixing state of the second intermediate product is verified; based on the result that the mixing state characteristic value is greater than or equal to the second preset mixing state characteristic threshold, it is determined that the mixing state meets the preset standard.

[0097] The increase in the mixing temperature is determined based on the ratio of the mixing state characteristic value to a first preset mixing state characteristic threshold, and the specific calculation method is as follows:

[0098] ΔT = T0 × (M / M1)

[0099] Wherein, ΔT is the increase in mixing temperature, T0 is the preset temperature, preferably 180℃, M is the characteristic value of the mixing state, and M1 is the first preset characteristic threshold of the mixing state.

[0100] Specifically, the first preset mixed state feature threshold and the second preset mixed state feature threshold are determined based on historical qualified batches;

[0101] From historical production, qualified batches with stable performance and formaldehyde absorption rate ≥95% are selected. The lower limit of the mixed state characteristic value among them is used as the first preset mixed state characteristic threshold, and the median of the mixed state characteristic value among them is used as the second preset mixed state characteristic threshold.

[0102] Specifically, verifying the mixing state of the second intermediate product includes:

[0103] Based on the result that the density of the second intermediate product is less than the preset density, it is determined that the mixing state of the second intermediate product meets the preset standard. Based on the result that the density of the second intermediate product is greater than or equal to the preset density, it is determined that the mass ratio of the foaming agent should be increased. Preferably, the preset density is 1000 kg / m³. Through experiments, it is determined that when the density is ≤1000 kg / m³, the product density is moderate and can form a uniform microporous structure, providing sufficient contact channels for formaldehyde gas.

[0104] In response to an increase in the mass percentage of the foaming agent, the increase in the mass percentage of the foaming agent is positively correlated with the difference between the density of the second intermediate product and the preset density;

[0105] The increase in the mass percentage of the foaming agent is determined based on the difference between the density of the second intermediate product and a preset density, specifically:

[0106] ΔW=W0×(ρ2-ρ0) / p0

[0107] Wherein, ΔW is the increase in the mass ratio of the foaming agent, W0 is the preset mass of the foaming agent added, ρ2 is the density of the second intermediate product, and ρ0 is the preset density.

[0108] Please see Figure 4 The diagram shows a flowchart of step S5 in the preparation method of the polymer composite material for catalytic degradation of formaldehyde according to an embodiment of the present invention. In step S5, adjusting the screw speed of the screw extruder based on the melt color uniformity feedback of the second intermediate product includes:

[0109] Step S51: Collect the color parameters of the second intermediate product and obtain its brightness value;

[0110] Step S52: Determine the color deviation value based on the difference between the brightness value and the preset color uniformity qualification threshold;

[0111] Step S53: The product of the ratio of the color deviation value to the preset color uniformity qualification threshold and the preset screw speed determines the screw speed adjustment value.

[0112] The specific calculation method is as follows:

[0113] R = (L - L0) / L0 × R0

[0114] Where R is the screw speed adjustment value, R0 is the preset screw speed, L is the brightness value of the second intermediate product, and L0 is the preset color uniformity qualification threshold, preferably 2.

[0115] It is understandable that, since nanoscale metal oxide particles themselves have a specific color, the more uniformly they are dispersed in the polymer matrix, the more uniform the melt color. Conversely, particle agglomeration leads to uneven and dark local colors. Experiments have verified that color uniformity is negatively correlated with particle dispersion index. When the brightness value is less than or equal to 2, the melt color uniformity meets the qualified standard, at which point the nanoscale metal oxide particles are uniformly dispersed in the matrix. When the brightness value is greater than 2, the formaldehyde absorption rate decreases significantly, by an average of 12.7%. Color uniformity is expressed as brightness variance, and the particle dispersion index is D90 / D10.

[0116] Specifically, in step S5, the screw speed is determined based on the sum of the preset screw speed and the screw speed adjustment value, and the adjustment range of the screw speed is positively correlated with the degree to which the formaldehyde absorption rate deviates from the preset target;

[0117] It is understandable that the positive correlation can be linear or nonlinear, and there is no specific limitation on the specific type. The slope of the linear positive correlation is also not limited and can be set according to the actual preparation conditions. The only requirement is that the greater the deviation of the formaldehyde absorption rate from the preset target, the greater the adjustment range of the screw speed. For example, if the adjustment range of the screw speed is set to ΔV, and the deviation of the formaldehyde absorption rate from the preset target is set to ΔR, then ΔV = ΔR × V0, where V0 is the base adjustment speed, set to 50 rpm. In historical production batches, when the base adjustment speed is 50 rpm, the mixing effect is optimal, the average formaldehyde absorption rate reaches 98.1%, and the equipment operates stably.

[0118] Specifically, after increasing the screw speed, the mixing temperature is adjusted according to the adjustment range of the screw speed, thereby reducing the mixing temperature. The reduction range of the mixing temperature is directly related to the reduction range of the screw speed, and the reduction range of the mixing temperature is the ratio of the screw speed before adjustment to the screw speed after adjustment.

[0119] Specifically, the preset mass ratio of the polymer composite material is 10 parts PVC particles, 15 parts random copolymer polypropylene, 2 parts nano-sized metal oxide particles, 0.1 parts adhesive, and 0.1 parts foaming agent.

[0120] The preset mass ratio of the nanoscale metal oxide particles is 1 part titanium dioxide and 1 part copper oxide. Example 1:

[0121] In this embodiment, the raw material ratio is 10 kg of PVC granules, 15 kg of random copolymer polypropylene, 1 kg of nano-grade titanium dioxide, 1 kg of nano-grade copper oxide, 0.1 kg of adhesive, 0.1 kg of foaming agent, 0.2 kg of antioxidant, and 0.5 kg of compatibilizer.

[0122] The melt flow rate of random copolymer polypropylene is 2.8 g / 10 min, the oxidation induction period is 18 min, and the amount of stabilizer added is determined to be 0.092 kg. Modification is carried out to obtain a first intermediate product. The first intermediate product is heated and blended with PVC particles, nano-sized metal oxide particles, adhesive, and foaming agent in a screw extruder to obtain a second intermediate product.

[0123] The mixing state characteristic value is determined based on the density of the second intermediate product and the aggregation index of the nanoscale metal oxide particles, and the mixing state of the second intermediate product is determined to meet the standard.

[0124] The second intermediate product is extruded and cooled to form a polymer composite material.

[0125] This embodiment fully demonstrates the control process. By specifically increasing the mixing temperature and fine-tuning the rotation speed based on the final performance, energy saving and prevention of material degradation are achieved through parameter linkage, resulting in a product with stable formaldehyde degradation efficiency and excellent appearance. Example 2:

[0126] In this embodiment, the raw material ratio is the same as in Example 1.

[0127] After mixing, the calculated characteristic value of the mixed state is greater than or equal to the first preset characteristic value but less than the second preset characteristic value, which needs to be verified. The density of the mixture is verified, and it is found that the measured density is greater than the preset density, indicating that the mixture is too dense and may not be foamed enough.

[0128] Increase the proportion of foaming agent by 0.05 parts according to the density difference ratio, add foaming agent and remix, then extrude and cool the mixture to form a mold.

[0129] This embodiment demonstrates the intelligent nature of the method. Blindly increasing the temperature under critical conditions may lead to material decomposition, but this invention accurately identifies the core problem of insufficient foaming through density verification. By adding a small amount of foaming agent, the porosity of the material is optimized, providing more channels for the diffusion and reaction of formaldehyde gas, thereby effectively improving product performance without changing the main process parameters. Example 3:

[0130] In this embodiment, to improve catalytic efficiency, the total number of nano-sized metal oxide particles is increased to 3 parts, of which titanium dioxide is 1.5 parts, copper oxide is 1.5 parts, and other components remain unchanged.

[0131] After mixing, due to the increased nanoparticle content and intensified aggregation, the measured characteristic value of the mixed state was much lower than the first preset characteristic threshold for the mixed state. It was determined that the mixing temperature needed to be significantly increased, and calculations showed that the mixing temperature should be raised to 205℃.

[0132] After high-temperature mixing, sampling tests showed that the formaldehyde absorption rate was much higher than the preset standard; to avoid the nanoparticles from agglomerating again, the rotation speed was not adjusted, and the mixture was directly extruded and cooled.

[0133] This embodiment demonstrates the strong adaptability of the present invention to formulation changes. For formulations with high active ingredient content, this method can forcibly break the agglomeration of nanoparticles by significantly adjusting process parameters, ensuring their full dispersion, thereby fully utilizing the theoretical high efficiency of high-content catalysts, and ultimately obtaining products with extremely excellent degradation performance. Example 4:

[0134] In this embodiment, the nanoscale metal oxide particles are replaced with 1 part titanium dioxide and 1 part zinc oxide;

[0135] When mixed at 180℃, the characteristic value of the mixed state was found to be unqualified. After increasing the temperature to 192℃ according to the calculation results, the mixed state met the standard.

[0136] Testing revealed that the melt color did not meet the preset standard. Increasing the screw speed by 8% brought the absorption rate to the standard. The mixture was then extruded and cooled.

[0137] In this embodiment, the optimal production process parameters corresponding to the new formula can be determined efficiently and accurately through a closed-loop feedback system, which greatly shortens the research and development cycle of the new material.

[0138] Comparative Example 1:

[0139] Comparative Example 1 has the same formulation as Example 1 and is prepared using a traditional method: all raw materials are directly heated and blended in a screw extruder, with the mixing temperature fixed at 180°C and the speed fixed, without any dynamic adjustment.

[0140] Performance tests were conducted on the products from Examples 1 to 4, and the results are as follows:

[0141] ;

[0142] As shown in Table 1, the preparation method of this invention significantly improves the formaldehyde degradation efficiency and stability of the product, with the formaldehyde absorption rate consistently above 95%, significantly higher than the traditional preparation method in Comparative Example 1. Furthermore, through real-time feedback and control, batch-to-batch variations are greatly reduced, ensuring the uniformity and reliability of product quality. Traditional methods exhibit significant performance fluctuations when dealing with highly active ingredients, and fixed parameters cannot effectively address material variations.

[0143] Density data shows that the products prepared by the method of this invention generally have lower densities than those produced by traditional methods. This proves that the mixing state verification logic in this invention can effectively identify insufficient foaming. By precisely increasing the foaming agent, a more uniform and denser microporous structure is formed. This structure provides a larger specific surface area and more reaction channels for formaldehyde gas, which is one of the key reasons for the performance improvement. The technical solution of this invention has now been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of this invention is obviously not limited to these specific embodiments. Without departing from the principles of this invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions resulting from these changes or substitutions will all fall within the scope of protection of this invention.

[0144] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a polymer composite material for catalytic degradation of formaldehyde, characterized in that, include: Step S1: Determine the amount of stabilizer to be added based on the melt flow rate and oxidation induction period of random copolymer polypropylene, and add stabilizer to the melt random copolymer polypropylene to modify it in order to obtain the first intermediate product. Step S2: Based on the relative deviation between the oxidation induction period of the first intermediate product and the preset target oxidation induction period, determine the preset dosage ratio of the first intermediate product and adjust it accordingly. Step S3: The first intermediate product is heated and blended with PVC particles, nano-sized metal oxide particles, adhesive, and foaming agent in a screw extruder to obtain the second intermediate product. Step S4: Determine the mixing state characteristic value based on the density of the second intermediate product and the aggregation index of the nanoscale metal oxide particles to determine whether the mixing state of the second intermediate product meets the standard, and verify the mixing state based on the density of the second intermediate product when the mixing state does not meet the standard. Specifically, the characteristic value of the mixed state is compared and analyzed with a first preset mixed state characteristic threshold and a second preset mixed state characteristic threshold; based on the result that the characteristic value of the mixed state is less than the first preset mixed state characteristic threshold, it is determined that the mixed state of the second intermediate product does not meet the preset standard and the mixing temperature is increased, and the increase in the mixing temperature is positively correlated with the ratio of the characteristic value of the mixed state to the first preset mixed state characteristic threshold; Based on the result that the mixing state characteristic value is greater than or equal to the first preset mixing state characteristic threshold and less than the second preset mixing state characteristic threshold, the mixing state of the second intermediate product is verified. Based on the result that the density of the second intermediate product is less than the preset density, the mixing state of the second intermediate product is determined to meet the preset standard. Based on the result that the density of the second intermediate product is greater than or equal to the preset density, the proportion of foaming agent is increased. The increase in the proportion of foaming agent is positively correlated with the difference between the density of the second intermediate product and the preset density. Based on the result that the mixed state feature value is greater than or equal to the second preset mixed state feature threshold, it is determined that the mixed state meets the preset standard; The first preset mixed state feature threshold is determined based on the lower limit of the mixed state feature value in the historical qualified batches, and the second preset mixed state feature threshold is determined based on the median of the mixed state feature value in the historical qualified batches. Step S5: In response to verifying the mixing state, the screw speed of the screw extruder is adjusted based on the melt color uniformity feedback of the second intermediate product, wherein the melt color uniformity is negatively correlated with the dispersion state of the nanoscale metal oxide particles in the matrix. Step S6: The second intermediate product is extruded and cooled to form a polymer composite material product.

2. The method for preparing a polymer composite material for catalytic degradation of formaldehyde according to claim 1, characterized in that, Step S1 includes: Step S11: Premix random copolymer polypropylene, antioxidant and compatibilizer at 80°C for 8 min; Step S12: Obtain the melt flow rate and oxidation induction period of the random copolymer polypropylene; Step S13: Based on the result that the oxidation induction period is less than a preset oxidation induction period threshold and the melt flow rate is less than a preset melt flow rate threshold, determine to add a stabilizer; Step S14: Determine the amount of stabilizer to be added based on the sum of the ratio of the oxidation induction period to the preset oxidation induction period threshold multiplied by a first weighting coefficient and the ratio of the melt flow rate to the melt flow rate threshold multiplied by a second weighting coefficient, so as to obtain the first intermediate product.

3. The method for preparing a polymer composite material for catalytic degradation of formaldehyde according to claim 2, characterized in that, Step S2 includes: Step S21: Obtain the oxidation induction period of the first intermediate product; Step S22: Determine the performance difference value based on the difference between the oxidation induction period of the first intermediate product and the preset oxidation induction period threshold. Step S23: Determine the relative deviation based on the ratio of the performance difference value to the preset oxidation induction period threshold. The relative deviation is used to quantify the degree of difference between the oxidation induction period of the first intermediate product and the preset oxidation induction period threshold. Step S24: Determine the intermediate product dosage ratio based on the product of the relative deviation and the preset dosage ratio of the first intermediate product.

4. The method for preparing a polymer composite material for catalytic degradation of formaldehyde according to claim 3, characterized in that, In step S4, the method for determining the characteristic value of the mixed state includes: Step S41: Detect density values ​​in the feeding section, compression section, and metering section of the screw extruder, calculate the average density value, and normalize the average density value. Step S42: Obtain the D90 and D10 particle sizes of the nanoscale metal oxide particles, and determine the aggregation index based on the ratio of the D90 particle size to the D10 particle size. Step S43: Based on the product of the normalized average density value and the first adjustment coefficient, the product of the aggregation index and the second adjustment coefficient is summed to determine the mixed state characteristic value.

5. The method for preparing a polymer composite material for catalytic degradation of formaldehyde according to claim 4, characterized in that, In step S5, adjusting the screw speed of the screw extruder based on the melt color uniformity feedback of the second intermediate product includes: Step S51: Collect the color parameters of the second intermediate product and obtain its brightness value; Step S52: Determine the color deviation value based on the difference between the brightness value and the preset color uniformity qualification threshold; Step S53: The product of the ratio of the color deviation value to the preset color uniformity qualification threshold and the preset screw speed determines the screw speed adjustment value.

6. The method for preparing a polymer composite material for catalytic degradation of formaldehyde according to claim 5, characterized in that, In step S5, the screw speed is determined based on the sum of the preset screw speed and the screw speed adjustment value.

7. The method for preparing a polymer composite material for catalytic degradation of formaldehyde according to claim 6, characterized in that, After increasing the screw speed, the mixing temperature is adjusted according to the adjustment range of the screw speed, and the mixing temperature is reduced. The reduction range of the mixing temperature is directly related to the reduction range of the screw speed.

8. A polymeric material for catalytic degradation of formaldehyde, prepared by the method according to any one of claims 1-7, characterized in that, The preset mass ratio of the polymer composite material is 10 parts PVC particles, 15 parts random copolymer polypropylene, 2 parts nano-sized metal oxide particles, 0.1 parts adhesive, 0.1 parts foaming agent, 0.2 parts antioxidant, and 0.5 parts compatibilizer. The preset mass ratio of the nanoscale metal oxide particles is 1 part titanium dioxide and 1 part copper oxide.

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