Low-VOC high-weather-resistance PCR-PP composite material and preparation method thereof

Abstract

The invention relates to the technical field of high polymer material auxiliaries, and discloses a low-VOC high-weather-resistance PCR-PP composite material and a preparation method thereof.The low-VOC high-weather-resistance PCR-PP composite material is prepared from, by weight, 5-15 parts of a main stable component containing a piperidine ring structure, 2-8 parts of aliphatic polyol with the hydroxyl value being 1600-1650 mgKOH / g, 10-30 parts of organic modified magnesium-aluminum hydrotalcite with the interlayer spacing larger than 2.6 nm, 5-15 parts of an auxiliary stable component containing a main stable component containing a main stable component containing a main stable component containing a main stable component containing a main stable component containing a main stable component containing a main stable component containing a main stable component containing a main stable Components are compounded through 110 deposition and 130 wetting, a hydrogen bond network coating layer with the thickness of 10-30 nm is formed in a 180-210 melting shear field, a physical pinning structure is constructed by means of intermolecular acting force among the components, diffusion activation energy of main stable components in a matrix is improved, migration loss is inhibited, and the bonding strength of the main stable components is improved. The alkaline active sites of the modified magnesium-aluminum hydrotalcite are used for in-situ neutralization of acidic oxidation intermediates generated by aging of regenerated polypropylene, so that an odor source is eliminated.

Description

Technical Field

[0001] This invention relates to a low-VOC, high-weather-resistant PCR-PP composite material and its preparation method, belonging to the field of polymer material additives technology. Background Technology

[0002] Current conventional formulations use hindered phenolic antioxidants and hindered amine light stabilizers to inhibit the thermo-oxidative degradation process of polymer chains. Polypropylene undergoes multiple thermal processing processes, which generate a large number of chain segment degradation products and are accompanied by an increase in free volume, resulting in a decrease in the diffusion energy barrier of the ingredients in the loose matrix.

[0003] Existing solutions lack displacement-constraining structures for additive molecules within the amorphous regions of the recycled matrix. Environmental temperature differences or long-term storage can cause additives to accumulate on the material surface, leading to whitening and blooming. Furthermore, photothermal-induced degradation of additive molecules on the surface produces sensory odor problems. Increasing the amount of additives or using macromolecular stabilizers to delay physical displacement can easily cause compatibility imbalances between the ingredients and the recycled matrix, resulting in phase separation of the additives during melt extrusion and affecting the stability of the material's mechanical properties. Besides the limitations of the additives' inherent properties or carrier morphology, systematic treatment solutions for recycled polypropylene also have shortcomings in their control logic. For example, [the following is an example from] authorization announcement number CN1121358. Chinese invention patent 70B discloses a method for purifying recycled polypropylene, which focuses on removing contaminants through high-energy-consuming physical means such as multi-stage solvent extraction, dissolution and filtration. Although this technology can purify the substrate to a certain extent, its process path depends on high-pressure circulation of solvent and completely ignores the inducing effect of microscopic defects in the recycled matrix on the migration of additives. Even after deep purification, the microscopic polarity imbalance problem caused by the recycled material after thermal processing still exists. This scheme lacks effective interfacial coupling logic to constrain stabilizer molecules, which leads to the stabilizer still being lost along loose channels during subsequent processing, making it difficult to balance the contradiction between low diffusion rate and high compatibility with the matrix.

[0004] Therefore, the technical problem to be solved by this invention is how to construct a coating layer with a pinning effect on the surface of an inorganic carrier through hydrogen bonding interactions between components while maintaining the chemical activity of the stabilizer, thereby increasing the diffusion activation energy of the adjuvant molecules in the loose matrix. Summary of the Invention

[0005] To address the problems mentioned in the background art, the technical solution of the present invention is as follows: a low-VOC, high-weather-resistant PCR-PP composite material, comprising the following components by weight: 5 to 15 parts of a main stabilizing component, wherein the main stabilizing component is a hindered amine light stabilizer containing a piperidine ring structure; 2 to 8 parts of a polyol component, wherein the polyol component has at least three hydroxyl groups and a hydroxyl value of to Aliphatic polyols; And 10 to 30 parts of a modified hydrotalcite-like carrier, wherein the modified hydrotalcite-like carrier has an interlayer spacing of [missing information]. Greater than Organically modified magnesium-aluminum hydrotalcite; The mass ratio of the polyol component to the main stabilizing component is: to The component has a microstructure formed by the following preparation procedure: a modified hydrotalcite-like carrier is placed in... to Preheated to the shear environment Add polyol components and dry mix them to allow the polyol components to be physically deposited on the edges of the sheets of the modified hydrotalcite-like carrier. Heat up to And a primary stabilizing component is introduced, which melts and wets the polyol component. The primary stabilizing component is in The dynamic viscosity at the following values ​​is to ; Finally, it is processed by a co-rotating twin-screw extruder. to Under the melting shear field, hydrogen bond networks are formed between the hydroxyl groups of the polyol component and the nitrogen atoms of the main stabilizing component, resulting in a network with a thickness of [thickness value missing] on the surface of the modified hydrotalcite-like carrier. to The coating layer is used to pin the main stabilizing component to the surface of the modified hydrotalcite carrier.

[0006] Preferably, the main stabilizing component further includes hindered phenolic antioxidants, and the mass ratio of hindered amine light stabilizers to hindered phenolic antioxidants is [missing information]. to Aliphatic polyols have a purity of not less than [amount missing]. And the melting point is to Pentaerythritol; wherein, the total molar amount of hydroxyl groups in the polyol component Total molar amount of nitrogen atoms in the main stable component The following stoichiometric ratio rules must be met: ,in, Let be the interfacial hydrogen bond saturation coefficient of the components, and The value is between 3 and 8 to ensure that the polyol component, as the main stabilizing component, provides an excess of hydrogen bonding sites.

[0007] Preferably, the interlayer modifying anions of the modified hydrotalcite support are selected from stearate, dodecylbenzenesulfonate, or combinations thereof; the particle size of the modified hydrotalcite support... for to Specific surface area is to .

[0008] Preferably, the coating layer has a dual-layer interface physical structure, which includes an inner anchoring layer composed of polyol components adsorbed on the surface of the modified hydrotalcite carrier, and an outer associating layer composed of main stabilizing components covering the inner anchoring layer.

[0009] Preferably, the main stable component is in The dynamic viscosity in the molten state is to This allows the main stabilizing component to be completely wetted and coated on the physical deposition surface of the polyol component in the melting shear field.

[0010] Preferably, the modified hydrotalcite carrier has alkaline active sites distributed on its surface. These alkaline active sites capture acidic oxidation intermediates generated by the thermo-oxidative aging of regenerated polypropylene through physical adsorption. The acidic oxidation intermediates include carboxylic acids and aldehydes.

[0011] Preferably, the components are in The thermal weight loss rate under the conditions is maintained at to between.

[0012] Preferably, the component is a particle size obtained by physical blending and melt compounding. to Micro powder.

[0013] Preferably, the hydrogen bond network forms a semi-compatible transition phase in the polypropylene matrix. The modulus of the semi-compatible transition phase is between that of the modified hydrotalcite carrier and the polypropylene matrix. The main stabilizing component is confined within the coating layer on the surface of the modified hydrotalcite carrier through the hydrogen bond network. Its diffusion activation energy in the recycled polypropylene matrix is ​​higher than that of the main stabilizing component in the free state.

[0014] A method for preparing a low-VOC, high-weather-resistant PCR-PP composite material includes the following steps: Step 1101, the modified hydrotalcite carrier is placed in... to Preheated to the shear environment Add polyol components and dry mix them to allow the polyol components to be physically deposited on the edges of the sheets of the modified hydrotalcite-like carrier. Step 1102, heat up to A main stabilizing component is introduced, which melts and wets the polyol component on the surface of the modified hydrotalcite carrier. Step 1103: The obtained pre-compound compound is fed into a co-rotating twin-screw extruder. to Melt extrusion is performed under a temperature gradient, causing hydrogen bond networks to form between the hydroxyl groups of the polyol component and the nitrogen atoms of the main stabilizing component, forming a layer with a thickness of [thickness missing] on the surface of the modified hydrotalcite-like carrier. to The coating layer.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. In the low-volatility luminescent and thermal stabilization of recycled polypropylene, the high-density hydroxyl groups in the molecular anchoring agent form hydrogen bonds with the basic nitrogen atoms in the main stabilizing component, inducing the formation of a hydrogen bond network coating layer with a specific spatial conformation on the surface of the modified hydrotalcite-like carrier. This transforms the stabilizer molecules from a conventional free diffusion state to an elastically constrained state bound by hydrogen bond forces. This coating structure increases the diffusion activation energy required for the stabilizer molecules to transition in the porous matrix of recycled polypropylene, reduces the migration rate and volatilization loss of the main stabilizing component during high-temperature processing or long-term storage, and enables small molecule components to achieve the low-volatility performance of macromolecular additives without sacrificing compatibility. This solves the problem of rapid depletion of additives in recycled polypropylene due to matrix defects.

[0016] 2. Modified hydrotalcite exhibits interlayer structure expansion after organic anion modification. Combined with the physical pinning effect of edge active sites on hydrogen bond clusters, it constructs a microscopic chemical reaction field inside the recycled polypropylene matrix. When acidic oxidation intermediates are generated during the thermo-oxidative aging process of recycled polypropylene, the stabilizer molecules anchored around the hydrotalcite immediately play a scavenging role. The generated acidic products are adsorbed and neutralized in situ by the interlayer alkaline sites, realizing the transformation from single-function protection to active elimination of odor sources and inhibiting the whitening or blooming phenomenon of products.

[0017] 3. Molecular anchoring agents, main stabilizing components, and modified hydrotalcite-like materials form an organic coating structure through polar correlation, establishing a semi-compatible transition interface with a modulus gradient between the inorganic carrier and the non-polar polypropylene matrix. Due to the physical flexibility of the hydrogen bond network coating layer, it alleviates the interfacial tension between hard inorganic particles and polymer chain segments, eliminates stress concentration points caused by conventional inorganic powders, improves the thermal stability of the material, avoids secondary damage to the toughness of recycled materials caused by additives, and maintains the overall mechanical property stability of the material. Attached Figure Description

[0018] Figure 1 This is a flowchart of the stepwise compounding and preparation process of the low-volatile luminescent and thermally stable components of the present invention; Figure 2 This is a flowchart illustrating the raw material composition and preparation process of the low-volatile luminescent and thermally stable component masterbatch of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to specific embodiments. The following embodiments are intended to explain and illustrate this invention, and are not intended to limit the scope of protection of this invention.

[0020] This invention provides a low-VOC, high-weather-resistant PCR-PP composite material and its preparation method. By constructing a hydrogen-bonded network coating structure at the component level, the diffusion rate of stabilizer molecules in the regenerated polypropylene matrix is ​​inhibited. The components include a main stabilizing component, a molecular anchoring agent, and an inorganic trapping carrier. The inorganic trapping carrier is an organically modified magnesium-aluminum hydrotalcite, and the interlayer spacing of this modified hydrotalcite carrier is [not specified]. Greater than nm; particle size of the carrier for to Specific surface area is to The interlayer modification anions are stearate, dodecylbenzenesulfonate, or a combination thereof; the support surface has basic active sites distributed to capture acidic oxidation intermediates generated during the thermo-oxidative aging of recycled polypropylene through physical adsorption; the acidic oxidation intermediates include carboxylic acids and aldehydes; the support, by weight, constitutes [amount missing]. portion to Parts; Modified hydrotalcite-like carrier native median diameter for to In step 1103, during the co-rotating twin-screw extrusion process, the specific energy consumption is controlled within... to This allows the main stabilizing component to form a thickness of [missing information] on the support surface. to The continuous coating structure, with its thickness determined by high-magnification observation of the edges of ultrathin slices using transmission electron microscopy combined with nitrogen elemental scanning results, resulted in a final micropowder powder obtained through melt composite and pelletizing. The powder underwent secondary granulation, resulting in a particle size distribution within [specific parameters missing]. to The molecular anchoring agent is an aliphatic polyol with at least three hydroxyl groups, specifically one with a purity of not less than [a certain percentage]. And the melting point is to Pentaerythritol, the polyol with a hydroxyl value of mgKOH / g to mgKOH / g, the molecular anchoring agent is, by weight, the component. portion to The mass ratio of the molecular anchoring agent to the main stabilizing component is [value missing]. to .

[0021] The main stabilizing component includes a hindered amine light stabilizer containing a piperidine ring structure; in some embodiments, the main stabilizing component further includes a hindered phenolic antioxidant, wherein the mass ratio of the hindered amine light stabilizer to the hindered phenolic antioxidant is [missing information]. to The main stable component is in The lower dynamic viscosity is Pa·s to Pa·s, in The dynamic viscosity in the molten state is Pa·s to Pa·s; The main stable component is, by weight, the component. portion to The component has a microstructure formed by the following preparation procedure, in which a modified hydrotalcite-like carrier is placed... rpm to Preheat to rpm under shear conditions Add polyol components and dry mix; the polyol components are physically deposited on the edges of the modified hydrotalcite-like carrier sheets; heat to... The main stabilizing component is introduced; the main stabilizing component melts and wets the polyol component; finally, it is extruded through a co-rotating twin-screw extruder. to Extrusion under a melt shear field; this process enables the formation of a hydrogen bond network between the hydroxyl groups of the polyol component and the nitrogen atoms of the main stabilizing component; a thickness of [missing information] is generated on the surface of the modified hydrotalcite-like carrier. nm to A nm-sized coating layer; the main stabilizing component is pinned to the surface of a modified hydrotalcite-like carrier; in engineering experiments to determine the internal proportions of the main stabilizing component, the mass ratio of hindered amine light stabilizer to hindered phenolic antioxidant was set at [value missing]. to The selection logic for this range lies in utilizing the hindered phenolic effect on the decomposition of peroxides in the early stages of thermo-oxidative degradation to provide a chemical environmental shield for the main stabilizing component to maintain a polar association state on the surface of the modified hydrotalcite-like carrier; when the mass ratio is lower than At this time, excessive phenolic components interfere with the binding of hindered amine molecules to pentaerythritol hydroxyl groups due to intermolecular hydrogen bond competition, resulting in a reduction in coating thickness. Below nm and causing excessive thermal weight loss; when the mass ratio is higher than... In the absence of phenolic components to quench free radicals, the basic nitrogen atom of the hindered amine molecule is susceptible to electrophilic attack from the residual catalyst in the regenerated polypropylene, leading to early failure of the pinned structure; experimental measurements show that... At a given mass ratio, the interfacial bonding energy of the components within the amorphous region of recycled polypropylene reaches its maximum value, enabling the material to... The oxidation induction period at high temperature is extended to More than 10 minutes.

[0022] In the melt extrusion process of step 1103, the screw assembly of the co-rotating twin-screw extruder is configured with at least three sets of staggered angles. The kneading block, by adjusting the screw speed, maintains the specific energy consumption of the material in the extrusion chamber at a certain level. to Within this range; this specific energy consumption range provides the critical shear pressure required to form a hydrogen bond network, ensuring that the molten main stable component can overcome the polar repulsion force on the surface of the modified hydrotalcite-like carrier and achieve wetting and coating; when the specific energy consumption is lower than When the shear strength is insufficient to drive effective collisions between the polyol component and the molecular chains of the main stable component, the coating layer exhibits a discontinuous distribution; when the specific energy consumption is higher than... At this time, excessive thermal shearing triggers localized thermal degradation of the piperidine ring of the hindered amine molecule; this energy balance control ensures that the particle size of the final micropowder component remains stable within a certain range. to Between these elements, a long-lasting photothermal stable fortress is constructed within the recycled polypropylene matrix; the component ratio satisfies the following stoichiometric ratio rule: ,in, The hydrogen bond saturation coefficient at the component interface. Values to ; This represents the total molar amount of hydroxyl groups in the polyol component, expressed in mol. Molar amount of total nitrogen atoms in the main stabilizing component, in mol; this ratio ensures that the polyol component provides excess hydrogen bonding sites for the main stabilizing component; interfacial hydrogen bond saturation coefficient. The calibration was based on the real-time readings of the absorbance tester for the carboxyl content of the raw material and the moisture analyzer, with a calibration coefficient. The value varies with the specific surface area of ​​the modified hydrotalcite carrier. The increase is positively correlated with the measurement of the carrier's specific surface area. Select, among which For calibration coefficients, The specific surface area of ​​the modified hydrotalcite carrier is given in units of... Moisture compensation coefficient The value is determined based on the moisture content of the raw material. Confirmed, moisture content for to hour Set as ,in This is the moisture compensation coefficient. This represents the percentage of moisture content by mass of recycled polypropylene feedstock, in units of... By increasing the proportion of polyol components to offset the competitive occupation of hydrogen bond sites by water, the hydrogen bond network coating layer can be made more efficient under different operating conditions. The above refers to the physical pinning thickness.

[0023] This component is produced through physical blending and melt compounding, with a particle size of [missing information]. to Micro powder; components in Under these conditions, the rate of thermal weight loss remains at to Between; a hydrogen bond network forms a semi-compatible transition phase in the polypropylene matrix; the modulus of this semi-compatible transition phase is between that of the modified hydrotalcite-like carrier and the polypropylene matrix; the main stabilizing component is confined within the surface coating layer of the modified hydrotalcite-like carrier through the hydrogen bond network; its diffusion activation energy in the recycled polypropylene matrix is ​​higher than that of the main stabilizing component in the free state; this structure increases the diffusion activation energy required for the stabilizer molecules to transition in the porous recycled polypropylene matrix, and reduces the migration rate of the main stabilizing component during high-temperature processing or long-term storage; the method for preparing this low-volatility luminescent and thermally stable component includes the following steps: Step 1101, the modified hydrotalcite-like carrier is placed in rpm to Preheat to rpm under shear conditions Add polyol components and dry mix to physically deposit the polyol components onto the edges of the modified hydrotalcite-like carrier sheets; Step 1102, heat to The main stabilizing component is introduced, causing it to melt and wet the polyol component on the surface of the modified hydrotalcite-like carrier; in step 1103, the obtained pre-compound is fed into a co-rotating twin-screw extruder. to Melt extrusion under a temperature gradient allows the hydroxyl groups of the polyol component to form a hydrogen bond network with the nitrogen atoms of the main stabilizing component, creating a layer with a thickness of [thickness value missing] on the surface of the modified hydrotalcite-like carrier. nm to A coating layer of nm.

[0024] Example 1: When recycled polypropylene products are in Under the above environmental temperature conditions, the degradation products of the matrix lead to an increase in free volume. Conventional hindered amine stabilizer molecules migrate along the channels to the surface of the product, causing blooming and emitting an odor. The low-volatility, photoluminescent, and thermally stable component of this invention, in specific embodiments, is derived from... Layer spacing for nm modified hydrotalcite-like carrier, Hydroxyl value Pentaerythritol at mgKOH / g and The main stabilizing component consists of pentaerythritol deposited at the edge of the modified hydrotalcite-like carrier lamellae. At the specified temperature, hindered amine molecules in the main stable component undergo polar association with pentaerythritol hydroxyl groups, and under the action of the melt shear field, produce a thickness of [missing information]. nm to A hydrogen bond network coating layer of nm.

[0025] By controlling the component ratio, the interfacial hydrogen bond saturation coefficient can be adjusted. Value , In the formula, The hydrogen bond saturation coefficient at the interface. This refers to the total molar amount of hydroxyl groups in the polyol component, expressed in mol. The total molar amount of nitrogen atoms in the main stabilizing component is expressed in mol. Nitrogen atoms in the main stabilizing component are bound by pentaerythritol hydroxyl groups, increasing the diffusion displacement resistance of the main stabilizing component within the amorphous region of the matrix. Measurements show that this component... thermal weight loss rate at temperature No additives are precipitated on the surface of recycled polypropylene products. The alkaline sites of the modified hydrotalcite carrier capture carboxylic acids in the degradation products of recycled polypropylene, and the additive molecules maintain stable distribution in the matrix.

[0026] Example 2: Differential scanning calorimetry and a constant-temperature aging oven were used to simulate the service condition of recycled polypropylene products under high-temperature storage conditions in summer. The original data used in the experiment came from a laboratory physical experimental platform, in which the co-rotating twin-screw extruder had a length-to-diameter ratio of... The specifications are as follows, and the temperature control accuracy is... The preparation process is as follows: the micro powder components obtained in steps 1101 to 1103 are prepared according to... A certain mass fraction was added to the recycled polypropylene matrix, and the mixture was melt-blended using a co-rotating twin-screw extruder. The granulation temperature was set at [temperature value missing]. to Within the range, injection molding to a thickness of The test sample was mm in size; the substrate in the test group contained a mass fraction of The calcium stearate residue was used to simulate the interference of metal salt catalysts in the actual regeneration process.

[0027] The experimental design included a control group and an experimental group with gradient changes. Control group 1 consisted of hindered amine light stabilizer 944 directly added to recycled polypropylene, while control group 2 was a simple physical blend of hindered amine light stabilizer 944 and unmodified magnesium-aluminum hydrotalcite. The core parameter was the interfacial hydrogen bond saturation coefficient. The underlying logic lies in balancing the hydrogen bond energy between stabilizer molecules with the dispersion kinetics of the components in the matrix. When the value is in the lower range, the nitrogen atoms on the surface of the hindered amine molecule cannot be sufficiently passivated, resulting in the evaporation rate being controlled by molecular thermal motion; when As the value increases, the hydrogen bond cluster density increases, and the hindered amine molecules are confined within the coating layer on the surface of the modified hydrotalcite-like carrier; the interfacial hydrogen bond saturation coefficient... The calculation method is as follows: ,in, The hydrogen bond saturation coefficient at the interface. This refers to the total molar amount of hydroxyl groups in the polyol component, expressed in mol. The total molar amount of nitrogen atoms in the main stable component, expressed in mol.

[0028] Table 1: Comparison of performance data of different component ratios in recycled polypropylene As shown in Table 1, the thermal weight loss rate of control group 1 reached [a certain value] due to the lack of a physical constraint structure. With the increase in the interfacial hydrogen bond saturation coefficient from Increase to The thickness of the coating layer is from nm increased to nm, thermal weight loss rate from Down to This trend indicates that the nitrogen atoms in the main stabilizing component are bound by the pentaerythritol hydroxyl groups, increasing the diffusion activation energy required for the transition of the auxiliary molecules to the surface; when the coefficient Set as That is, below the lower limit of the range, the hydroxyl sites are insufficient to form a continuous hydrogen bond network, causing the thermal weight loss rate to rebound to [a certain value]. Slight blooming occurred; in the comparative experiment verifying the synergistic effect of the components within the main stabilizing component, the mass ratios were set as follows: , , , and Five parallel sample groups were used to evaluate the ability of each sample group to retain the mechanical properties of recycled polypropylene using isothermal aging tests; the test data showed that as the mass ratio increased from... Increase to Recycled polypropylene after undergoing Hour Tensile strength retention rate after hot air aging from Upgraded to This nonlinear performance growth demonstrates the sacrificial protection mechanism of hindered phenolic antioxidants for the hydrogen bond coating layer, namely, that the phenolic components preferentially consume the free radicals that diffuse from the matrix to the carrier interface, thereby maintaining the effective loading density of hindered amine molecules in the hydrogen bond network; when the ratio deviates from the defined optimal window, the rate of decrease in the elongation at break of the sample accelerates.

[0029] Performance data also reflects the upper limit of the value range, when the coefficient Increase to Subsequently, excessive polyols led to a polarity imbalance between the components and the polypropylene matrix, causing the notched impact strength of the recycled polypropylene sample to decrease. Descending to Furthermore, the side reaction between excess hydroxyl groups and residual catalyst caused the odor level to rise to [a higher level]. Level; proved the interfacial hydrogen bond saturation coefficient defined by this invention. The range of values ​​represents the optimal window for achieving synergistic effects between photothermal stability and matrix compatibility. Experimental results confirm that the alkaline active sites on the surface of the modified hydrotalcite-like carrier, by capturing acidic degradation intermediates and combining the fixation effect of the hydrogen bond coating layer on the stabilizer, inhibited the loss of additives and eliminated the characteristic odor of recycled materials.

[0030] Example 3: This example combines Figures 1 to 2 This document describes a low-VOC, high-weather-resistant PCR-PP composite material and its preparation method. Figure 1 As shown, the preparation process is horizontally divided into five logical units: raw material preparation, high-speed mixer, pre-compound system, twin-screw extruder, and finished product components. The vertical execution path begins with the preparation of three core components in the raw material preparation stage. The modified hydrotalcite carrier is put into the high-speed mixer and preheated to 110°C under shear conditions. The polyol component pentaerythritol is added. After dry mixing and deposition, the system is heated to 130°C and the main stabilizing component is introduced. At this temperature, melt wetting and compounding are carried out and the pre-compound is output. Then, the pre-compound is fed into the twin-screw extruder and melt shearing processing is completed in the temperature gradient range of 180°C to 210°C, so that hydrogen bond networks are formed between the components. Finally, the finished micro powder component with a particle size of 3μm to 5μm is obtained through the granulation process.

[0031] like Figure 2 As shown, the raw material side of this process system includes component A, which provides long-lasting light stability (i.e., a high molecular weight hindered amine light stabilizer), component B, which inhibits thermo-oxidative degradation (i.e., an antioxidant), component C, which neutralizes acidic substances (i.e., an acid scavenger), and a matrix, i.e., a polypropylene carrier resin, used to carry the dispersing agent. The above four types of raw materials are weighed in a specific weight ratio and then physically mixed in a high-speed mixing stage to form a uniform premix. The premix is ​​fed into a twin-screw extruder for plasticizing, dispersing, and pelletizing to complete melt extrusion granulation. After the product undergoes dehydration and sealing and drying packaging, a low-volatility, light- and heat-stable component masterbatch is finally obtained as a high-performance additive for recycled polypropylene.

[0032] Example 4: For a sample containing a mass fraction of The regenerated polypropylene material from the metal oxide catalyst, prepared using the method described in this invention, involves preheating the modified hydrotalcite-like support in a high-speed mixer to [temperature missing]. This temperature is used to activate the thermal motion of stearic acid modified segments and expose edge basic sites; the temperature is then increased to... The addition of a main stabilizing component softens the hindered amine light stabilizer 944, allowing it to penetrate the interlayer of the modified hydrotalcite-like carrier. The hydroxyl groups of pentaerythritol act as proton donors, forming hydrogen bond clusters with the nitrogen atoms of the hindered amine molecules. Under the high shear field of a co-rotating twin-screw extruder, a thickness of [thickness value missing] is generated. A coating layer of nm.

[0033] Based on diffusion coefficient With temperature The diffusion activation energy is calculated using the following formula based on the varying test data. : ,in, This is the diffusion coefficient, in units of... , Pre-exponential factors, in units of , The activation energy is for diffusion, and the unit is 1. , Let be the ideal gas constant, and take the value of . , Absolute temperature, unit: Calculations showed that the free hindered amine molecules in the regenerated polypropylene matrix... for After the formation of the hydrogen bond network coating layer, the main stable component Upgraded to ;exist UV aging in hours and Changes in the yellow index of the sample after constant temperature cycling test for Furthermore, electron microscopy observations showed that the coating structure on the surface of the modified hydrotalcite-like carrier particles remained intact, and no additives were enriched at the phase interface. The main stabilizing component was pinned to the carrier surface and the residual catalyst in the matrix was physically isolated by the temperature-separated pre-compounding procedure.

[0034] Example 5: Under conditions where the oxidation degree of different batches of recycled polypropylene raw materials fluctuates, in order to eliminate the influence of raw material component differences on the coating quality, infrared spectroscopy was used to determine the oxidation degree of the raw materials at a wavenumber of [wavenumber missing]. The carbonyl peak intensity at the specified position is used to calculate the oxidation degree parameter of the raw material based on the measured absorbance. This allows for adjustment of the feeding ratio of the molecular anchoring agent and the main stabilizing component, thereby increasing the interfacial hydrogen bond saturation coefficient. The value of the parameter varies with the degree of oxidation. The adjusted saturation coefficient satisfies the formula. ,in, The adjusted interfacial hydrogen bond saturation coefficient. The preset base coefficient has a value of , The calibration coefficient is in units of 1000 ppm. Its value varies with the specific surface area of ​​the modified hydrotalcite carrier. to Choose from, A dimensionless parameter for characterizing the carboxyl content of raw materials.

[0035] The components were prepared according to the calibrated component ratios using steps 1101 to 1103. After equilibration at various temperature zones in a co-rotating twin-screw extruder, the components were melt-compounded with the corresponding batch of recycled polypropylene raw materials. The rheological state of the material under shear field was determined by monitoring the pressure fluctuations at the melt pump output. When the measured thermal weight loss rate of the product was within a certain range... to Within the specified range, the hydrogen bond network on the surface of the modified hydrotalcite carrier is in a dynamic saturated state. The thickness of the hydrogen bond coating layer varies with the chemical properties of the raw materials, reducing the frequency of degradation reactions between the residual catalyst and the main stabilizing component in the recycled polypropylene. Under different material conditions from different recycled sources, the pinning stability of the main stabilizing component in the amorphous region of the matrix is ​​maintained.

[0036] Example 6: In scenarios involving high humidity production and fluctuating raw material moisture content, to eliminate the impact of residual moisture on the quality of hydrogen bond network coating formation, a moisture meter was used to obtain the initial moisture content of the recycled polypropylene raw material. This moisture analyzer has The quality resolution is mg and the measurement repeatability deviation is no higher than mg. Based on the measured moisture content Introducing a moisture compensation coefficient Hydrogen bond saturation coefficient at the interface Online correction is performed, and the corrected interface hydrogen bond saturation coefficient satisfies the formula. ,in, This is the corrected interfacial hydrogen bond saturation coefficient. The basic saturation coefficient is determined based on the degree of oxidation. This is the moisture compensation coefficient, and its value ranges from... to between, The percentage of water content by mass of recycled polypropylene feedstock, in units of... .

[0037] Simultaneous calibration coefficients The value is determined by measuring the specific surface area of ​​the modified hydrotalcite carrier. Determined, satisfying the relation , The calibration coefficient is in units of 1000 ppm. , The specific surface area of ​​the modified hydrotalcite carrier is given in units of... This process is used to adjust the flow ratio of the molecular anchoring agent to the main stabilizing component, so that the hydrogen bonding sites cover the nitrogen atoms of the hindered amine molecule; the preparation program in steps 1101 to 1103 is started, and the temperature of the feeding section of the co-rotating twin-screw extruder is set at... to The space between the two sections is used to remove free moisture from the raw materials, maintains stable pressure in the melting section, and allows the product to... The thermal weight loss rate under the conditions is at to Within the specified range, the coating thickness on the surface of the modified hydrotalcite carrier is [value missing]. The thickness of the hydrogen bond coating varies with the water content of the raw material, and the main stabilizing component maintains pinning stability in the amorphous region of the matrix.

[0038] 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.

[0039] 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 low-VOC, high-weather-resistant PCR-PP composite material, characterized in that, By weight, it includes the following components: 5 to 15 parts of the main stabilizing component, which is a hindered amine light stabilizer containing a piperidine ring structure; 2 to 8 parts of a polyol component, wherein the polyol component has at least three hydroxyl groups and a hydroxyl value of to Aliphatic polyols; And 10 to 30 parts of a modified hydrotalcite-like carrier, wherein the modified hydrotalcite-like carrier has an interlayer spacing of [missing information]. Greater than Organically modified magnesium-aluminum hydrotalcite; The mass ratio of the polyol component to the main stabilizing component is: to The component has a microstructure formed by the following preparation procedure: a modified hydrotalcite-like carrier is placed in... to Preheated to the shear environment Add polyol components and dry mix them to allow the polyol components to be physically deposited on the edges of the sheets of the modified hydrotalcite-like carrier. Heat up to And a primary stabilizing component is introduced, which melts and wets the polyol component. The primary stabilizing component is in The dynamic viscosity at the following values ​​is to ; Finally, it is processed by a co-rotating twin-screw extruder. to Under the melting shear field, hydrogen bond networks are formed between the hydroxyl groups of the polyol component and the nitrogen atoms of the main stabilizing component, resulting in a network with a thickness of [thickness value missing] on the surface of the modified hydrotalcite-like carrier. to The coating layer is used to pin the main stabilizing component to the surface of the modified hydrotalcite carrier.

2. The low-VOC, high-weather-resistant PCR-PP composite material according to claim 1, characterized in that, The main stabilizing component also includes hindered phenolic antioxidants, and the mass ratio of hindered amine light stabilizers to hindered phenolic antioxidants is [missing information]. to Aliphatic polyols have a purity of not less than [amount missing]. And the melting point is to Pentaerythritol; wherein, the total molar amount of hydroxyl groups in the polyol component Total molar amount of nitrogen atoms in the main stable component The following stoichiometric ratio rules must be met: ,in, Let be the interfacial hydrogen bond saturation coefficient of the components, and The value ranges from 3 to 8.

3. The low-VOC, high-weather-resistant PCR-PP composite material according to claim 1, characterized in that, The interlayer modifying anions of the modified hydrotalcite support are selected from stearate, dodecylbenzenesulfonate, or combinations thereof; Particle size of modified hydrotalcite carrier for to Specific surface area is to .

4. The low-VOC, high-weather-resistant PCR-PP composite material according to claim 1, characterized in that, The coating layer exhibits a dual-layer interface physical structure, which includes an internal anchoring layer composed of polyol components adsorbed on the surface of the modified hydrotalcite-like carrier, and an external associating layer composed of main stabilizing components covering the outside of the internal anchoring layer.

5. The low-VOC, high-weather-resistant PCR-PP composite material according to claim 1, characterized in that, The main stable component in The dynamic viscosity in the molten state is to This allows the main stabilizing component to be completely wetted and coated on the physical deposition surface of the polyol component in the melting shear field.

6. The low-VOC, high-weather-resistant PCR-PP composite material according to claim 1, characterized in that, The modified hydrotalcite carrier has alkaline active sites distributed on its surface. These alkaline active sites capture acidic oxidation intermediates generated by the thermo-oxidative aging of regenerated polypropylene through physical adsorption. The acidic oxidation intermediates include carboxylic acids and aldehydes.

7. The low-VOC, high-weather-resistant PCR-PP composite material according to claim 1, characterized in that, Components in The thermal weight loss rate under the conditions is maintained at to between.

8. The low-VOC, high-weather-resistant PCR-PP composite material according to claim 1, characterized in that, The components are made by physical blending and melt compounding, resulting in a particle size of [missing information]. to Micro powder.

9. The low-VOC, high-weather-resistant PCR-PP composite material according to claim 1, characterized in that, Hydrogen bond networks form a semi-compatible transition phase in the polypropylene matrix. The modulus of the semi-compatible transition phase is between that of the modified hydrotalcite carrier and the polypropylene matrix. The main stabilizing component is confined within the coating layer on the surface of the modified hydrotalcite carrier through the hydrogen bond network. Its diffusion activation energy in the recycled polypropylene matrix is ​​higher than that of the main stabilizing component in the free state.

10. A method for preparing a low-VOC, high-weather-resistant PCR-PP composite material, characterized in that, The preparation of the low-VOC, high-weather-resistant PCR-PP composite material according to claim 1 includes the following steps: Step 1101, the modified hydrotalcite carrier is placed in... to Preheated to the shear environment Add polyol components and dry mix them to allow the polyol components to be physically deposited on the edges of the sheets of the modified hydrotalcite-like carrier. Step 1102, heat up to A main stabilizing component is introduced, which melts and wets the polyol component on the surface of the modified hydrotalcite carrier. Step 1103: The obtained pre-compound compound is fed into a co-rotating twin-screw extruder. to Melt extrusion is performed under a temperature gradient, causing hydrogen bond networks to form between the hydroxyl groups of the polyol component and the nitrogen atoms of the main stabilizing component, forming a layer with a thickness of [thickness missing] on the surface of the modified hydrotalcite-like carrier. to The coating layer.

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