Preparation method of low-VOC-release PCR-PP (Polymerase Chain Reaction-Polypropylene) inorganic ingredient

Abstract

The invention relates to the technical field of high polymer material ingredients, and discloses a preparation method of a low-VOC-release PCR-PP inorganic ingredient, which comprises the following steps: mixing a mesoporous structure inorganic carrier with a molten organic plugging component, and driving the organic plugging component to fill the pore channel of the inorganic carrier through a shearing force field; establishing an asymmetric temperature gradient on an interface, and driving a polar group to move to a deep layer of a pore channel by using a pressure difference so as to construct a space shielding layer; monitoring the cooling process of the organic plugging component, applying a transient high-frequency shear pulse to a crystallization initial critical zone, inducing a macromolecular chain to form an extended chain crystal embedded into an inorganic carrier crystal lattice, and constructing a physical topology anchoring structure. And space shielding and rigid locking of volatile organic compounds are realized.

Description

Technical Field

[0001] This invention relates to a method for preparing PCR-PP inorganic ingredients containing low VOC release, belonging to the field of polymer material formulation technology. Background Technology

[0002] Currently, the application of post-consumer recycled polypropylene (PCR-PP) in the manufacture of high-performance composite materials is continuously increasing in resource recycling technologies. To improve the mechanical strength and thermal stability of the material, inorganic powders such as talc and sepiolite are usually added to the polymer matrix as ingredients. According to existing technologies, the surface of inorganic carriers is often modified with silane or titanate coupling agents to improve the interfacial wettability between inorganic components and organic resins. However, when processing PCR-PP matrices with high odor, traditional surface modification methods face thermal stability obstacles. Because PCR-PP produces a strong thermal degradation effect at extrusion processing temperatures of 180 to 220°C, the organic modified layer on the carrier surface undergoes secondary pyrolysis and releases small molecule volatiles. At this time, the inorganic ingredients not only cannot effectively capture impurities in the matrix, but also generate new sources of volatile organic compound release.

[0003] To address these issues, the industry has attempted to suppress emissions by increasing the adsorption capacity of porous materials or enhancing the vacuum devolatilization capability of production lines. Analysis has revealed that blindly increasing the adsorbent content can easily trigger bidirectional migration within the physical pores. During the thermal aging cycle of the final product, adsorbate molecules undergo secondary desorption. Furthermore, conventional processes struggle to eliminate the thermo-pressure repulsion effect generated by gases within the mesopores at high temperatures, resulting in modified components only depositing on the outer surface of the particles and failing to penetrate deep into the pores for physical locking. Existing technologies also have shortcomings in dynamic process control methods. For example, Chinese invention patent application CN120329659A discloses a low-VOC polypropylene composite material and its preparation process, which involves adding fluorene-based silicone oil benzophenone-coated talc to a polypropylene matrix. Powdered activated carbon is conventionally melt-blended with activated carbon in a twin-screw extruder to reduce volatile organic compound (VOC) emissions. However, analysis of the process reveals that the method relies solely on the static physical adsorption mechanism of the multi-level pore structure of activated carbon to capture VOC components. There is a fundamental mismatch between the characteristics of conventional high-temperature extrusion processes and the static surface thermodynamic adsorption principle. Without active surface pore pressure control and deep crystallization anchoring intervention, the high-temperature shear flow field easily destroys the fragile interface structure of the simple blend. Controlling the path at the overall material mixing level cannot overcome the thermal expansion and repulsion effect of the gas inside the mesopores at high temperatures. It is also impossible to build a rigid physical barrier in the deep pores of inorganic materials to resist the violent thermal movement of polymer chains. This leads to irreversible secondary desorption and escape of small molecules adsorbed in the shallow pores under subsequent thermal stress or alternating hot and cold conditions.

[0004] Therefore, the technical problem to be solved by this invention is how to provide a technical solution that can overcome the thermal pressure repulsion effect inside the pores, realize the directional anchoring of functional components in the deep pores of the inorganic carrier, and prevent the secondary escape of captured molecules. Summary of the Invention

[0005] To address the problems in the background art, the technical solution of the present invention is as follows: A method for preparing PCR-PP inorganic ingredients containing low VOC release, comprising the following steps:

[0006] Step S101: Place the inorganic carrier with a mesoporous structure into a mixing device equipped with shear blades, add the organic plugging component in a molten state to the mixing device, adjust the rotation frequency of the shear blades to 1000Hz to 3000Hz to generate a shear force field, and drive the organic plugging component to wet the surface of the inorganic carrier and fill into the mesoporous channels of the inorganic carrier by the shear force field.

[0007] Step S102: Control the flow of external cooling medium to the outer wall of the mixing equipment so that the cooling rate of the outer surface of the inorganic carrier is higher than the cooling rate inside the mesoporous channel to establish an asymmetric temperature gradient. Use the asymmetric temperature gradient to induce the residual gas inside the mesoporous channel to generate a pressure difference of 0.05MPa to 0.15MPa pointing to the depth of the channel. The pressure difference drives the polar groups in the organic blocking component to move to the depth of the mesoporous channel to construct a spatial shielding layer.

[0008] Step S103: Monitor the cooling curve of the organic blocking component. When the temperature of the organic blocking component drops to the crystallization initiation critical zone temperature determined by the starting point of the cooling curve deviating from the baseline, apply a transient high-frequency shear pulse lasting 2s to 10s to the mixing equipment. The shear rate of the transient high-frequency shear pulse is greater than or equal to the reciprocal of the relaxation time of the macromolecular chain of the organic blocking component at the crystallization initiation critical zone temperature. This induces the macromolecular chain to crystallize oriented along the wall of the mesoporous channel to construct extended chain crystals embedded in the inorganic carrier lattice, forming a physical topological anchoring structure.

[0009] Preferably, the inorganic carrier is selected from wollastonite, talc, or magnesium hydroxide, and the average pore size of the inorganic carrier is 10 nm to 50 nm, and the specific surface area is 150 m² / g to 300 m² / g; the organic plugging component is selected from polyethylene wax, polypropylene wax, or Fischer-Tropsch wax, and its dropping point temperature is 105 °C to 155 °C, and its viscosity at 140 °C is 10 mPa·s to 500 mPa·s.

[0010] Preferably, before step S101, the method further includes: modifying the inner wall of the mesoporous channels of the inorganic carrier with aluminate or titanate to construct chemical anchoring points, so as to reduce the capillary resistance when the organic blocking components penetrate into the mesoporous channels.

[0011] Preferably, in step S102, the circulation speed of the cooling medium is adjusted so that the radial outer cooling rate of the inorganic carrier is 5 K / s to 15 K / s higher than the central axial cooling rate.

[0012] Preferably, in step S103, the frequency of the transient high-frequency shear pulse is 50Hz to 200Hz, and the force of the transient high-frequency shear pulse is...

[0013] Preferably, the organic plugging component contains 0.5% to 3.0% by mass of a nucleating agent, which generates heterogeneous crystal origins under the action of transient high-frequency shear pulses, increasing the distribution density of extended chain crystals in the mesoporous channels.

[0014] Preferably, the shear rate γ of the transient high-frequency shear pulse satisfies the following formula: γ≥1 / τ, where τ is the relaxation time of the organic plugging component at the crystallization initiation critical temperature.

[0015] Preferably, after completing step S103, a modified inorganic compound is generated; the method further includes: mixing the modified inorganic compound with recycled polypropylene resin, which serves as the matrix of the composite material, at a mass ratio of 1:5 to 1:20, and performing melt blending.

[0016] Preferably, during melt blending, the vacuum exhaust pressure is controlled between -0.08 MPa and -0.1 MPa to remove residual volatile organic compounds from the blended product.

[0017] Preferably, the thickness of the physical barrier layer formed at the mesoporous pore opening by the physical topological anchoring structure is not less than 50 nm.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. In the preparation of PCR-PP inorganic ingredients containing low VOC release, an asymmetric temperature gradient is established between the thermal shear expansion stage of the inorganic carrier and the introduction stage of the adsorption components. The volume contraction of the gas inside the mesopore due to exogenous rapid cooling generates a surface negative pressure pointing towards the depth of the pores. This negative pressure driving force overcomes the diffusion resistance and thermal expansion repulsion effect of the adsorption medium at the capillary opening, achieving precise enrichment and spatial isolation of targeted adsorption groups in the depth of the mesopores. This avoids the ineffective adhesion of active ingredients to the outer surface of the inorganic powder and their oxidation and pyrolysis in subsequent high-temperature processing, and eliminates the background of volatiles in the ingredients themselves.

[0020] 2. By combining the transient high-frequency shear pulse applied in the critical region of the polymer plugging layer crystallization initiation, the macromolecular chains in the semi-viscous flow state are driven to flow along the mesoporous pore walls to induce orientation crystallization. The straightened chain crystals constructed thereby are embedded in the depressions of the inorganic lattice to form a physical topological riveting structure. The orientation internal stress generated by this structure effectively compensates for the thermal shrinkage mismatch between the organic plugging phase and the inorganic pore wall, eliminates the micro-annular leakage channels caused by interface peeling, and ensures that the captured volatile molecules are rigidly locked in the inner cavity of the ingredient throughout the entire product life cycle.

[0021] 3. By coupling the thermal shear rheological field generated by mechanochemical activation with the dynamic response logic based on pore topology feature retrieval, the differences in the surface geometric distribution of the inorganic carrier are translated into deterministic process control boundaries. This ensures that each batch of material achieves millisecond-level engagement at the transient micro-negative pressure suction window and phase change blocking node. This high degree of coordination between the physical execution path and the surface fluid response enhances the system's strong batch consistency and engineering robustness, enabling inorganic batching to actively capture and permanently imprison residual small molecules in recycled polypropylene without relying on additional vacuum devolatilization equipment. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating the core steps and process flow for preparing low-VOC-release PCR-PP inorganic ingredients according to the present invention.

[0023] Figure 2 This is a diagram showing the interactive architecture between the core control module of this invention and peripheral testing and production equipment.

[0024] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0026] A method for preparing PCR-PP inorganic ingredients containing low VOC release includes the following steps:

[0027] Step S101: Place the inorganic carrier with a mesoporous structure into a mixing device equipped with shear blades, add the organic plugging component in a molten state into the mixing device, adjust the rotation frequency of the shear blades to 1000Hz to 3000Hz to generate a shear force field, and drive the organic plugging component to wet the surface of the inorganic carrier and fill into the mesoporous channels of the inorganic carrier by the shear force field.

[0028] Step S102: Control the flow of external cooling medium to the outer wall of the mixing equipment so that the cooling rate of the outer surface of the inorganic carrier is higher than the cooling rate inside the mesoporous channel to establish an asymmetric temperature gradient. Use the asymmetric temperature gradient to induce the residual gas inside the mesoporous channel to generate a pressure difference of 0.05MPa to 0.15MPa pointing to the depth of the channel. The pressure difference drives the polar groups in the organic blocking component to move to the depth of the mesoporous channel to construct a spatial shielding layer.

[0029] Step S103: Monitor the cooling curve of the organic blocking component. When the temperature of the organic blocking component drops to the crystallization initiation critical zone temperature determined by the starting point of the cooling curve deviating from the baseline, apply a transient high-frequency shear pulse lasting 2s to 10s in the mixing equipment. The shear rate of the transient high-frequency shear pulse is greater than or equal to the reciprocal of the relaxation time of the macromolecular chain of the organic blocking component at the crystallization initiation critical zone temperature. This induces the macromolecular chain to crystallize oriented along the wall of the mesoporous channel to construct extended chain crystals embedded in the inorganic carrier lattice, forming a physical topological anchoring structure.

[0030] Preferably, the inorganic carrier is selected from wollastonite, talc, or magnesium hydroxide, and the average pore size of the inorganic carrier is 10 nm to 50 nm, and the specific surface area is 150 m² / g to 300 m² / g; the organic plugging component is selected from polyethylene wax, polypropylene wax, or Fischer-Tropsch wax, and its dropping point temperature is 105 °C to 155 °C, and its viscosity at 140 °C is 10 mPa·s to 500 mPa·s.

[0031] Preferably, before step S101, the method further includes: modifying the inner wall of the mesoporous channels of the inorganic carrier with aluminate or titanate to construct chemical anchoring points, so as to reduce the capillary resistance when the organic blocking components penetrate into the mesoporous channels.

[0032] Preferably, in step S102, the circulation speed of the cooling medium is adjusted so that the radial outer cooling rate of the inorganic carrier is 5 K / s to 15 K / s higher than the central axial cooling rate.

[0033] Preferably, in step S103, the frequency of the transient high-frequency shear pulse is 50Hz to 200Hz, and the force of the transient high-frequency shear pulse is...

[0034] Preferably, the organic plugging component contains 0.5% to 3.0% by mass of a nucleating agent, which generates heterogeneous crystal origins under the action of transient high-frequency shear pulses, increasing the distribution density of extended chain crystals in the mesoporous channels.

[0035] Preferably, the shear rate γ of the transient high-frequency shear pulse satisfies the following formula: γ≥1 / τ, where τ is the relaxation time of the organic plugging component at the crystallization initiation critical temperature.

[0036] Preferably, after completing step S103, a modified inorganic compound is generated; the method further includes: mixing the modified inorganic compound with recycled polypropylene resin, which serves as the matrix of the composite material, at a mass ratio of 1:5 to 1:20, and performing melt blending.

[0037] Preferably, during melt blending, the vacuum exhaust pressure is controlled between -0.08 MPa and -0.1 MPa to remove residual volatile organic compounds from the blended product.

[0038] Preferably, the thickness of the physical barrier layer formed at the mesoporous pore opening by the physical topological anchoring structure is not less than 50 nm.

[0039] Example 1: In the high-temperature modification of post-consumer recycled polypropylene matrix used in automotive interior parts manufacturing, there is a high concentration of free aldehydes and ketones emitted due to polymer self-degradation. Traditional surface treatment processes suffer from interfacial thermodynamic mismatch under these conditions. The low molecular weight organic modification layer covering the inorganic carrier surface undergoes secondary pyrolysis in the extrusion thermal field at 180°C to 220°C. Simultaneously, the pre-adsorbed guest molecules inside the mesopores migrate outward due to thermal expansion and repulsive forces, causing the ingredients to lose their ability to capture volatile organic compounds and transform into a new source of persistent odor emission. An inorganic carrier with a mesoporous structure and an average pore size of 10nm to 50nm is placed in a mixing device equipped with shear blades. Adding to this mixing device... The molten organic plugging component is used to generate a shear force field by adjusting the rotation frequency of the shear blades to 1000Hz to 3000Hz. This shear force field drives the organic plugging component to wet the surface of the inorganic carrier and fill the mesoporous channels of the inorganic carrier. The external cooling medium is controlled to flow to the outer wall of the mixing equipment, so that the cooling rate of the outer surface of the inorganic carrier is higher than that of the interior of the mesoporous channels to establish an asymmetric temperature gradient. This asymmetric temperature gradient induces the residual gas inside the mesoporous channels to shrink in volume due to local rapid cooling, generating a pressure difference of 0.05MPa to 0.15MPa pointing towards the depth of the channels. This pressure difference directly drives the polar groups in the organic plugging component to overcome the thermal expansion of the orifice and repel the airflow, moving into the depth of the mesoporous channels to construct a spatial shielding layer.

[0040] The cooling curve of the organic plugging component is monitored. When the temperature of the organic plugging component drops to the critical temperature of crystallization initiation determined by the starting point of the cooling curve deviating from the baseline, a transient high-frequency shear pulse lasting 2 to 10 seconds is applied to the mixing equipment. The shear rate γ of this transient high-frequency shear pulse is set to satisfy the formula γ ≥ 1 / τ, where τ is the relaxation time of the organic plugging component at the critical temperature of crystallization initiation. This high-frequency shear pulse changes the thermodynamic disordered contraction path of the macromolecular chains in the semi-viscous flow state, inducing the macromolecular chains to crystallize oriented along the walls of the mesoporous channels to construct extended chain crystals embedded in the inorganic carrier lattice, forming a physical topological anchoring structure. According to the transient heat conduction law, the rate of frictional heat dissipation at the microscale interface is dominated by the thermal diffusivity of the material. The inorganic carrier has a higher thermal conductivity than the organic polymer, and the mesoporous pore walls provide a high specific surface area. The transient high-frequency shear pulse inputs mechanical heat energy in a short time. The inorganic framework conducts and absorbs the pulse, setting the pulse duration to 2s to 10s, so that the local temperature rise cycle at the interface is lower than the relaxation time of the semi-viscous flow macromolecular main chain thermal fracture. Shear heat generation is derived through the transient thermal conduction effect of the inorganic framework, avoiding secondary pyrolysis of the organic blocking components. The extended chain crystal forms a physical barrier layer with a thickness of not less than 50nm at the mesoporous channel opening. The orientation internal stress generated by this layer compensates for the shrinkage mismatch that occurs during the phase transformation crystallization stage, cuts off the micro-annular leakage channels formed by interface peeling. When the modified inorganic material is subsequently melt-blended with recycled polypropylene resin at a mass ratio of 1:5 to 1:20, the deeply anchored polar groups capture the small odor molecules released by the polymer matrix in situ. After cooling and molding, the physical topological anchoring structure maintains the spatial shielding and rigid locking of volatile organic compounds, so that the overall carbon emission index of the composite material meets the emission standards of the closed space.

[0041] Example 2: In a standardized testing environment for evaluating the volatile organic compound (VOC) emission characteristics of recycled polypropylene composites, traditional surface-modified inorganic fillers experienced thermal shrinkage mismatch after high-temperature extrusion, leading to the reopening of mesopores. A co-rotating twin-screw extruder was selected as the mixing equipment, with a screw length-to-diameter ratio of 40:1. The extruder was equipped with an independent zoned water-cooled temperature control module, achieving a temperature control accuracy of 0.1℃. Porous silica with an average pore size of 32.5 nm was selected as the inorganic carrier with a mesoporous structure. Maleic anhydride-grafted polypropylene with a melt index of 1.2 g / 10 min was selected as the organic blocking component. Test data were obtained from samples with a detection limit of 0. Gas chromatography-mass spectrometry (GC-MS) with a concentration of 0.01 mg / m³ and a transmission electron microscope (TEM) with a resolution of 0.5 nm were used. The duration of the transient high-frequency shear pulse was set to balance the degree of macromolecular chain orientation and crystallization with the technical state of excessive shearing leading to chain breakage. When the organic plugging component was in a semi-viscous flow state, a shear pulse was applied to change the arrangement of the molecular chains along the pore wall. The relaxation time τ of the organic plugging component at the crystallization initiation critical temperature of 125.5℃ was determined to be 0.005 s. Based on the shear rate γ satisfying the formula γ≥1 / τ, the shear rate threshold was determined. The duration of the transient high-frequency shear pulse was set to 6 s. Control and experimental groups were set up. The boundary effects of process parameters were determined. The control group used a conventional natural cooling process to prepare the ingredients. The experimental group established an asymmetric temperature gradient corresponding to the pore pressure difference gradient based on the difference in cooling medium flow rate. The measurement data showed that when the pore pressure difference was outside the lower limit of 0.02 MPa, the transmission electron microscope image showed that the organic plugging layer remained at the mesopore opening, and the physical barrier layer thickness was 12.4 nm. The gas chromatography-mass spectrometry recorded that the emission of aldehydes and ketones from the complex was 15.6 mg / m³. When the pore pressure difference was 0.05 MPa, the polar groups moved into the deeper layers of the pores, and the physical barrier layer thickness increased to 51 nm. At 2 nm, the volatile emission rate decreased to 4.3 mg / m³. When the pore pressure difference increased to 0.10 MPa and a shear force field with a rotation frequency of 2100 Hz was applied, the physical barrier layer thickness reached a saturation state of 85.6 nm, and the volatile emission rate decreased to 1.1 mg / m³. When the pressure difference increased to 0.18 MPa, which exceeded the range, the deep gas compression rebound expansion caused the physical barrier layer to rupture, and the volatile emission rate rebounded to 8.9 mg / m³. This set of nonlinear data verified that the pressure difference of 0.05 MPa to 0.15 MPa caused by the temperature gradient constitutes the working window for deep anchoring of polar groups.

[0042] A partially missing control group was constructed by stripping transient high-frequency shear pulse characteristics. Background alkane stray gas with a concentration of 0.5 mg / m³ was actively injected into the sampling path of a gas chromatography-mass spectrometry (GC-MS) system to simulate volatile disturbance noise in an industrial workshop. Maintaining a pressure difference of 0.10 MPa but without applying a shear pulse satisfying the set shear rate formula, the physical barrier layer thickness was measured to be 80.5 nm. After stray gas disturbance and thermal cycling aging tests, the baseline of volatile emission data showed broadband fluctuations, with the emission value drifting from an initial 1.5 mg / m³ to 8.3 mg / m³. Transmission electron microscopy images showed a 3.5 nm wide annular stripping gap at the aperture. In the experimental group, which included the application of a transient high-frequency shear pulse lasting 6 s with a shear rate of 250 / s, macromolecular chains formed extended chain crystals embedded in the inorganic carrier lattice along the pore walls. Under the influence of impurities and thermal aging, a smooth detection baseline was output, with the emission value maintained at 1.2 mg / m³. No interfacial peeling was detected. The comparative data showed a synergistic effect of pressure difference-driven deep sealing and pulse shear induction in the crystallization critical zone. The pressure difference provided the space occupation basis, and the pulse shear generated orientation internal stress to compensate for the phase transformation shrinkage mismatch. The combination of the two cut off the leakage channels of the interfacial micro-annulus and filtered out background emission disturbances. The quantitative analysis data of gas emission showed that the modified inorganic material prepared by shear force field driving, asymmetric temperature gradient induced pressure reduction and high-frequency shear pulse intervention in the crystallization critical zone, after being blended with recycled polypropylene resin, maintained the emission of free aldehyde and ketone volatiles below 1.5 mg / m³. The physical topological anchoring structure of the extended chain crystal maintained the rigid locking state of the mesoporous interface, and the output of low emission parameters of volatile organic compounds of polymer system was shown.

[0043] Example 3: In the test environment for evaluating the volatile organic compound emission characteristics of recycled polypropylene composites, the technical problem of thermal shrinkage mismatch after high-temperature extrusion of surface-modified inorganic fillers leading to the reopening of mesopores was encountered. A co-rotating twin-screw extruder was selected as the mixing equipment, with the screw length-to-diameter ratio set to 40:1. The mixing equipment was equipped with an independent zoned water-cooled temperature control module, achieving a temperature control accuracy of 0.1℃. Porous silica with an average pore size of 32.5nm was selected as the inorganic carrier with a mesoporous structure, and maleic anhydride-grafted polypropylene with a melt index of 1.2g / 10min was selected as the organic blocking component. Gas chromatography-mass spectrometry with a detection limit of 0.01mg / m³ and transmission electron microscopy with a resolution of 0.5nm were selected to output test data.

[0044] The duration of the transient high-frequency shear pulse was determined based on the technical requirements of balancing the crystallization perfection of the macromolecular chain orientation and avoiding excessive shearing that could lead to chain breakage. When the organic plugging component was in a semi-viscous flow state, a shear pulse was applied to change the arrangement of the molecular chains along the mesopore walls. The relaxation time τ of the organic plugging component at the crystallization initiation critical temperature of 125.5℃ was measured to be 0.005s. Based on the shear rate γ satisfying the formula γ≥1 / τ, the shear rate threshold was determined, and the duration of the transient high-frequency shear pulse was set to 6s. Boundary effects of process parameters were measured using an out-of-range control group and the sample group of this invention. The out-of-range control group used a natural cooling process to prepare the feed. The sample group of this invention established a pore pressure difference gradient corresponding to an asymmetric temperature gradient based on the difference in cooling medium flow rate. The measured data showed that when the pore pressure difference was outside the lower limit of 0.02MPa, the transmission electron microscope image showed that the organic plugging layer remained at the mesopore opening, and the physical barrier layer thickness was measured to be 12.4nm. Gas chromatography-mass spectrometry (GC-MS) recorded the emission of aldehydes and ketones from the complex as 15.6 mg / m³. When the pore pressure difference was 0.05 MPa, polar groups migrated deeper into the pores, and the physical barrier layer thickness increased to 51.2 nm. GC-MS then recorded the emission of volatiles as decreasing to 4.3 mg / m³. When the pore pressure difference increased to 0.10 MPa and a shear field with a rotation frequency of 2100 Hz was applied, the physical barrier layer thickness reached [missing value]. At a saturated state of 85.6 nm, the gas chromatography-mass spectrometry (GC-MS) recorded a decrease in volatile emissions to 1.1 mg / m³. When the pressure difference increased to 0.18 MPa, which was outside the range, the deep gas compression rebound expansion caused the physical barrier layer to rupture, and the GC-MS recorded a rebound in volatile emissions to 8.9 mg / m³. This set of measurement data confirms that the pressure difference of 0.05 MPa to 0.15 MPa caused by the temperature gradient constitutes the working window for deep anchoring of polar groups.

[0045] The low-VOC-emission PCR-PP inorganic compound obtained in the aforementioned steps was fed into a twin-screw extruder at a mass ratio of 1:10 with recycled polypropylene resin. The mixture was melt-blended at 190°C, and the resulting composite material was obtained by water-cooling, stretching, and pelletizing. Quantitative analysis of gas emissions confirmed that the inorganic compound prepared by the steps of shear force field driving, asymmetric temperature gradient induced pressure reduction, and transient high-frequency shear pulse in the critical region of crystallization initiation, after being blended with recycled polypropylene resin, maintained the emission of free aldehydes and ketones below 1.5 mg / m³. The physical topological anchoring structure constructed by the extended chain crystals maintained the rigid closed state of the mesoporous interface, resulting in low emission characteristics of volatile organic compounds in the composite material system.

[0046] Example 4: When the system faces fluctuations in the rheological properties of raw materials across batches and interference from ambient temperature, samples of organic plugging components from a specified batch are extracted and input into a combined rotational rheometer and differential scanning calorimeter testing platform. The cooling rate is set to match the flow rate of the cooling medium on the outer wall of the mixing equipment. The continuous change sequence of the sample's storage modulus and heat flow rate with decreasing temperature is recorded. The tangent line on the heat flow rate curve corresponding to the extension line of the melting plateau is taken as the baseline of the cooling curve. The corresponding temperature calibration is performed when the heat flow rate signal deviates from this cooling curve baseline and the difference reaches 0.1 W / g. The crystallization initiation critical temperature is used as the starting temperature. Dynamic small-amplitude oscillatory shear at frequencies from 0.1 Hz to 100 Hz is applied at this temperature. The angular frequency ω at the intersection of the storage modulus and the loss modulus is extracted. The relaxation time is determined according to the formula τ = 1 / ω, where τ is the relaxation time and ω is the angular frequency. Based on the principles of energy conservation and fluid shear heating, static testing and calibration of crystallization thermodynamic parameters require shear heat compensation before application to continuous mixing conditions. The control module loads the shear heat compensation relationship, including equipment speed and melt apparent viscosity, and dynamically executes the temperature... Set as the static calibration temperature of the critical region for crystallization initiation. Subtract the shear temperature rise compensation value ΔT, which is calculated using the formula ΔT=k⋅N⋅η. In the formula, k represents the dimensionless characteristic heat dissipation coefficient related to the heat exchange efficiency of the extruder cooling water jacket, N records the measured real-time screw speed, and η represents the apparent viscosity of the organic plugging component under the current flow field. The dynamic execution temperature is continuously updated by collecting the real-time speed and viscosity fluctuations of the mixing equipment. This is used as the threshold for triggering transient high-frequency shear pulses in continuous production.

[0047] Organic plugging components, calibrated rheologically and thermodynamically, were introduced into a test section mixing device equipped with distributed temperature sensors and micro pressure transmitters. Based on capillary condensation and the fluid state equation in confined spaces, the pressure of the deep fluid in the mesoporous channels drifted with the temperature gradient inside and outside the pores and changes in pore volume. A high-frequency thermocouple array with a measurement accuracy of 0.1℃ was installed on the cavity wall and at the central screw axis of the mixing unit. A cavity total pressure sensor with an accuracy of 0.001MPa was installed at the exhaust valve port. The global temperature drop curve and total pressure drop parameters of the cavity were simultaneously collected during the adjustment of the cooling medium flow rate. The porosity and average pore size characteristic values ​​of the inorganic carrier were simultaneously measured using a nitrogen adsorption instrument. The collected parameters were input into a built-in confined fluid PVT nonlinear inverse algorithm to calculate the equivalent deep negative pressure value generated by the cooling and contraction of residual gas in the surface channels. The control module used the inverse algorithm to output the equivalent deep negative pressure value to replace the direct measurement data by the physical probe and adjust the cooling... The initial flow rate of the medium is 10 L / min, and the rotation frequency of the shear blade is maintained. The temperature time series of the outer surface of the inorganic carrier and the inside of the mesoporous channel are collected simultaneously. The temperature time series is smoothed according to the built-in filtering algorithm, and the difference in cooling rate between the outer surface and the inside is calculated. A fitting function is established between the difference in cooling rate and the channel pressure difference collected by the micro pressure transmitter. The flow rate of the cooling medium is adjusted until the channel pressure difference output by the fitting function is in the set range of 0.05 MPa to 0.15 MPa. This flow rate is locked as the standard control parameter. Based on the locked flow rate and the previously calibrated crystallization initiation critical zone temperature and relaxation time τ, the controller triggers a transient high-frequency shear pulse that meets the constraint condition of formula γ≥1 / τ during continuous production, where γ is the shear rate and τ is the previously measured relaxation time. The output presents a stable spatial shielding layer and a physical topological anchoring structure containing low VOC-releasing PCR-PP inorganic feed.

[0048] Example 5: When facing the switching of the physical pore size of the inorganic carrier, the system injects the inorganic carrier to be tested and the organic plugging component in a molten state into the airtightness testing mixing unit. Miniature temperature sensors and pressure probes are respectively configured at the mesopore orifice and the deep layer of the pore. The flow rate of the external cooling medium is adjusted to generate a continuous cooling rate difference sequence covering the range of 0.1℃ / s to 5.0℃ / s. The transient pressure difference signal output by the pressure probe in the deep layer of the pore is collected at each cooling rate difference level. The continuous cooling rate difference sequence and the corresponding transient pressure difference signal are input into a preset polynomial regression model using the least squares algorithm. The function coefficient value when the fitting error converges to the preset minimum value is extracted to establish a fitting function between the cooling rate difference and the pore pressure difference.

[0049] During continuous mixing production, the control module extracts the temperature difference between the outer surface of the inorganic carrier and the inside of the mesoporous channels, which is obtained in real time by the distributed temperature sensor, and inputs it into the fitting function. It calculates and outputs the corresponding real-time channel pressure difference estimate. Based on the numerical deviation between the real-time channel pressure difference estimate and the set range of 0.05MPa to 0.15MPa, a flow rate adjustment command is generated to control the flow of the external cooling medium to the outer wall of the mixing equipment. This maintains the physical state of the residual gas volume contraction inside the mesoporous channels induced by the asymmetric temperature gradient within the pressure difference range of 0.05MPa to 0.15MPa, thus preparing a low-VOC-release PCR-PP inorganic ingredient with a spatial shielding layer.

[0050] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing PCR-PP inorganic ingredients containing low VOC release, characterized in that, Includes the following steps: Step S101: Place the inorganic carrier with a mesoporous structure into a mixing device equipped with shear blades, add the organic plugging component in a molten state to the mixing device, adjust the rotation frequency of the shear blades to 1000Hz to 3000Hz to generate a shear force field, and drive the organic plugging component to wet the surface of the inorganic carrier and fill into the mesoporous channels of the inorganic carrier by the shear force field. Step S102: Control the flow of external cooling medium to the outer wall of the mixing equipment so that the cooling rate of the outer surface of the inorganic carrier is higher than the cooling rate inside the mesoporous channel to establish an asymmetric temperature gradient. Use the asymmetric temperature gradient to induce the residual gas inside the mesoporous channel to generate a pressure difference of 0.05MPa to 0.15MPa pointing to the depth of the channel. The pressure difference drives the polar groups in the organic blocking component to move to the depth of the mesoporous channel to construct a spatial shielding layer. Step S103: Monitor the cooling curve of the organic blocking component. When the temperature of the organic blocking component drops to the crystallization initiation critical zone temperature determined by the starting point of the cooling curve deviating from the baseline, apply a transient high-frequency shear pulse lasting 2s to 10s to the mixing equipment. The shear rate of the transient high-frequency shear pulse is greater than or equal to the reciprocal of the relaxation time of the macromolecular chain of the organic blocking component at the crystallization initiation critical zone temperature. This induces the macromolecular chain to crystallize oriented along the wall of the mesoporous channel to construct extended chain crystals embedded in the inorganic carrier lattice, forming a physical topological anchoring structure.

2. The preparation method of a low-VOC-release PCR-PP inorganic ingredient according to claim 1, characterized in that, The inorganic carrier is selected from wollastonite, talc, or magnesium hydroxide, with an average pore size of 10 nm to 50 nm and a specific surface area of ​​150 m² / g to 300 m² / g; the organic plugging component is selected from polyethylene wax, polypropylene wax, or Fischer-Tropsch wax, with a dropping point temperature of 105 °C to 155 °C and a viscosity of 10 mPa·s to 500 mPa·s at 140 °C.

3. The preparation method of a low-VOC-release PCR-PP inorganic ingredient according to claim 1, characterized in that, Before step S101, the method further includes: modifying the inner wall of the mesoporous channels of the inorganic carrier with aluminate or titanate to construct chemical anchoring points, so as to reduce the capillary resistance when the organic blocking components penetrate into the mesoporous channels.

4. The preparation method of a low-VOC-release PCR-PP inorganic ingredient according to claim 1, characterized in that, In step S102, the circulation speed of the cooling medium is adjusted so that the radial outer cooling rate of the inorganic carrier is 5 K / s to 15 K / s higher than the central axial cooling rate.

5. The preparation method of a low-VOC-release PCR-PP inorganic ingredient according to claim 1, characterized in that, In step S103, the frequency of the transient high-frequency shear pulse is 50Hz to 200Hz, and the force of the transient high-frequency shear pulse is...

6. The preparation method of a low-VOC-release PCR-PP inorganic ingredient according to claim 1, characterized in that, The organic plugging component contains 0.5% to 3.0% by mass of nucleating agent. Under the action of transient high-frequency shear pulse, the nucleating agent generates heterogeneous crystal origins, increasing the distribution density of extended chain crystals in the mesoporous channels.

7. The preparation method of a low-VOC-release PCR-PP inorganic ingredient according to claim 1, characterized in that, The shear rate γ of the transient high-frequency shear pulse satisfies the following formula: γ≥1 / τ, where τ is the relaxation time of the organic plugging component at the critical temperature of crystallization initiation.

8. The preparation method of a low-VOC-release PCR-PP inorganic ingredient according to claim 1, characterized in that, After completing step S103, a modified inorganic compound is generated; the method further includes: mixing the modified inorganic compound with recycled polypropylene resin, which serves as the matrix of the composite material, at a mass ratio of 1:5 to 1:20, and performing melt blending.

9. The preparation method of a low-VOC-release PCR-PP inorganic ingredient according to claim 8, characterized in that, During melt blending, the vacuum exhaust pressure is controlled between -0.08 MPa and -0.1 MPa to remove residual volatile organic compounds from the blended product.

10. The preparation method of a low-VOC-release PCR-PP inorganic ingredient according to claim 1, characterized in that, The thickness of the physical barrier layer formed at the mesoporous pore opening by the physical topological anchoring structure is not less than 50 nm.

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