PVC composite material based on in-situ reaction compatibilization and lamellar filler dispersion regulation and preparation method and application thereof

Abstract

The present application relates to the field of polymer material modification and polymer composite material preparation, and in particular to PVC composite material based on in-situ reaction compatibilization and layered filler dispersion control, and its preparation method and application. The PVC composite material comprises the following components by weight: 100 parts of polyvinyl chloride resin; 10-30 parts of chlorinated polyethylene; 5-15 parts of polyolefin elastomer; 1-5 parts of bentonite; 0.5-2 parts of ordinary epoxy resin; 0.5-3 parts of hydrogenated bisphenol A epoxy resin; 0.5-3 parts of acrylic acid; and 0.05-1 parts of initiator. The present application controls the pretreatment of layered filler, the reaction of polyolefin elastomer and the step-by-step control of the final mixing process of the multiphase system, so that different functional components play a role in different stages, thereby improving the dispersion state of bentonite in the system and the interfacial bonding between the phases of the polymer, and improving the toughness of the material while maintaining good rigidity, processing performance and insulation performance.

Description

Technical Field

[0001] This invention relates to the field of polymer material modification and polymer composite material preparation, specifically to PVC composite materials based on in-situ reaction compatibilization and layered filler dispersion regulation, their preparation methods, and applications. Background Technology

[0002] Polyvinyl chloride (PVC) is widely used in building profiles, pipes, sheets, wire and cable sheaths, automotive interiors, and insulation components due to its abundant raw material sources, low cost, good flame retardancy, excellent chemical corrosion resistance, and diverse processing methods. Especially in outdoor building materials and electrical insulation, PVC combines economy and functionality, maintaining a stable foundation for long-term industrial applications. However, rigid PVC has significant drawbacks: firstly, its high molecular chain rigidity, strong notch sensitivity, and low elongation at break make it prone to brittle fracture under impact, bending, or low-temperature service conditions; secondly, PVC is susceptible to dehydrochlorination degradation during heating, light exposure, and long-term outdoor service, leading to molecular chain breakage, color changes, and mechanical property degradation, thus limiting its further application in high-impact, high-weather-resistance environments.

[0003] To improve the brittleness of PVC, existing technologies typically involve blending with elastomers for toughening, such as chlorinated polyethylene (CPE), ethylene-octene copolymers or polyolefin elastomers (POE), acrylate elastomers, and MBS. Among these, CPE is commonly used as an industrially mature PVC toughening agent due to its relatively close polarity to PVC; while POE is used to further improve the material's impact resistance due to its excellent elasticity and outstanding low-temperature toughness.

[0004] However, the existing toughening routes generally have the following technical bottlenecks: (1) It is difficult to balance toughness and rigidity: Although the addition of elastomers can improve impact strength and elongation at break, it usually causes a decrease in tensile strength, flexural modulus, surface hardness and heat deformation capacity. Especially in rigid PVC systems, as the content of flexible components such as CPE and POE increases, the system as a whole tends to soften, making it difficult to meet the requirements of high toughness and high rigidity at the same time, forming the common problem of "toughening means reducing rigidity". (2) Insufficient compatibility between non-polar elastomers and PVC: PVC is a strongly polar polymer, while polyolefin elastomers such as POE have low polarity. The interfacial compatibility between the two is poor, and phase separation is easy to occur, resulting in low stress transfer efficiency and many interfacial defects, which in turn affects mechanical properties and long-term stability. Although CPE can play an interfacial transition role to a certain extent, it is still difficult to fundamentally solve the interfacial bonding problem of multiphase systems by simply relying on physical blending. (3) Inorganic nanofillers are prone to agglomeration and have difficulty exerting a reinforcing effect: Using inorganic fillers such as bentonite, montmorillonite, and nano silica to reinforce and modify PVC is a common approach to improve rigidity, dimensional stability, and aging resistance. Among them, bentonite has a layered silicate structure, which theoretically can exert excellent reinforcing and barrier effects after intercalation or exfoliation dispersion. However, in practical applications, the interlayer forces of bentonite are strong, and it is easy to agglomerate in organic polymers. If the interface is not properly treated, it will not only be difficult to improve the performance, but will also introduce defects, weakening the toughness and processing fluidity of the material. (4) Traditional epoxy modification has a shortcoming in weather resistance: In the existing technology, epoxy resin is often used in PVC thermal stabilization or reactive compatibilization systems to absorb HCl released during the degradation process through epoxy groups, or to react with carboxyl-containing components to form a certain interface bond. However, commonly used bisphenol A type epoxy resin contains an aromatic ring structure, which is prone to photo-oxidation reaction under the combined action of ultraviolet light, oxygen, and heat, leading to yellowing, surface aging, and performance degradation of the material. Therefore, simply using conventional bisphenol A epoxy resin is insufficient to meet the requirements of high weather-resistant PVC materials for long-term outdoor use. (5) Existing processes are mostly simple one-step blending methods, which are difficult to precisely control the microstructure: Currently, most PVC blending modification schemes adopt one-step feeding extrusion or internal mixing blending methods, which simultaneously add PVC, elastomers, fillers and additives into the equipment for direct processing. This method is simple, but it is difficult to simultaneously achieve the effective opening of the bentonite interlayer structure, the reactive grafting of elastomers such as POE, the interfacial chemical bridging between multiple components, and the stable construction of the final microstructure. Therefore, the one-step method can often only obtain ordinary physical blending systems, with insufficient ambiguity of the phase interface inside the material, and the nanofillers are prone to agglomeration, ultimately making it difficult to achieve the synergistic unity of "high toughness, high rigidity and high weather resistance".

[0005] In summary, existing PVC modification technologies still present significant contradictions in their ability to toughen, strengthen, improve compatibility, and enhance weather resistance. There is an urgent need to develop a new material system and preparation process to significantly improve the toughness, weather resistance, and long-term service stability of PVC while maintaining or increasing its rigidity. Therefore, this invention provides PVC composite materials based on in-situ reaction compatibilization and layered filler dispersion regulation, along with their preparation methods and applications. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide PVC composite materials based on in-situ reaction compatibilization and layered filler dispersion control, as well as their preparation methods and applications. The aim is to improve the dispersion state of bentonite in the system and the interfacial bonding between polymer phases by step-by-step controlling the pretreatment of layered fillers, the reaction of polyolefin elastomers, and the final mixing process of the multiphase system. This improves the material's toughness while maintaining good rigidity, processability, and insulation properties.

[0007] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: In a first aspect, a PVC composite material based on in-situ reaction compatibilization and layered filler dispersion regulation, the PVC composite material comprising the following components in parts by weight: 100 parts of polyvinyl chloride resin; 10-30 parts of chlorinated polyethylene; 5-15 parts of polyolefin elastomer; 1-5 parts bentonite; 0.5 to 2 parts of ordinary epoxy resin; 0.5 to 3 parts of hydrogenated bisphenol A epoxy resin; Acrylic acid 0.5 to 3 parts; Initiator 0.05 to 1 part.

[0008] Based on the above technical solution, the present invention can be further improved as follows.

[0009] Furthermore, the polyolefin elastomer is a polyoctene-ethylene copolymer (POE). The initiator is at least one of dicumyl peroxide, benzoyl peroxide, di-tert-butyl peroxide, and azobisisobutyronitrile; The hydrogenated bisphenol A epoxy resin is a hydrogenated bisphenol A type diglycidyl ether epoxy resin.

[0010] Furthermore, the bentonite is at least one of sodium-based bentonite, calcium-based bentonite, and organically modified bentonite; The common epoxy resin is at least one of bisphenol A type epoxy resin and glycidyl ether type epoxy resin.

[0011] Furthermore, the PVC composite material also includes the following components in parts by weight: 2-8 parts heat stabilizer; 0.5 to 5 parts of lubricant and / or processing aid.

[0012] Furthermore, the heat stabilizer is at least one of calcium-zinc stabilizer and organotin stabilizer; The lubricant and / or processing aid is at least one of stearic acid, paraffin wax, oxidized polyethylene wax, and acrylate.

[0013] Furthermore, the PVC composite material comprises the following components in parts by weight: 100 parts of polyvinyl chloride resin; 15-25 parts of chlorinated polyethylene; 8-12 parts of polyolefin elastomer; 2-5 parts bentonite; 1-2 parts of ordinary epoxy resin; 1-2 parts of hydrogenated bisphenol A epoxy resin; 1-2 parts acrylic acid; Initiator 0.1–0.5 parts; Heat stabilizer 3-6 parts; 1 to 3 parts of lubricant and / or processing aid.

[0014] Furthermore, the weight ratio of the ordinary epoxy resin to the bentonite is 0.2:1 to 1:1, the weight ratio of the hydrogenated bisphenol A epoxy resin to the acrylic acid is 0.3:1 to 2:1, and the weight ratio of the chlorinated polyethylene to the polyolefin elastomer is 1.5:1 to 5:1.

[0015] Secondly, the preparation method of PVC composite materials based on in-situ reaction compatibilization and layered filler dispersion regulation includes the following steps: (1) Pretreatment: Bentonite is premixed with ordinary epoxy resin so that the ordinary epoxy resin enters the bentonite interlayer to obtain pretreated bentonite. (2) Reactive extrusion: The pretreated bentonite, polyolefin elastomer, acrylic acid, hydrogenated bisphenol A epoxy resin and initiator are added to a twin-screw extruder and reactively extruded under heating and shearing conditions to obtain reactive masterbatch; (3) Final mixing and molding: The reactive masterbatch is melt-blended with polyvinyl chloride resin and chlorinated polyethylene, and after granulation, it is molded by injection molding, extrusion or compression molding to obtain PVC composite material.

[0016] Furthermore, the premixing in step (1) is carried out using an open mill, internal mixer or high-speed mixer, with a processing temperature of 40 to 120°C and a processing time of 5 to 30 minutes.

[0017] Further, in step (2), the twin-screw extruder is provided with at least three heating zones along the material conveying direction, and the temperatures of each heating zone are 130-150℃, 155-175℃ and 145-165℃ respectively; the screw speed of the twin-screw extruder is 100-500 rpm, and an exhaust section is provided during the reactive extrusion process to remove volatiles and unreacted small molecules; wherein, in step (2), polyvinyl chloride resin and chlorinated polyethylene are not added; in step (3), polyvinyl chloride resin and chlorinated polyethylene are added for melt blending so that the reactive masterbatch is dispersed in the continuous polyvinyl chloride phase; In step (3), melt blending is carried out using a kneader or a twin-screw extruder; the blending temperature of melt blending is 160-180℃, and the blending time is 3-15 min.

[0018] Thirdly, based on the application of PVC composite materials with in-situ reaction compatibilization and layered filler dispersion regulation, the aforementioned PVC composite materials with in-situ reaction compatibilization and layered filler dispersion regulation are used in the preparation of outdoor building materials, wire and cable sheaths, door and window profiles, outdoor panels, insulating structural components or high impact-resistant structural components.

[0019] The core of this invention lies in the phased division of labor among different functional components and the control of the multiphase structure formation process through step-by-step processing. In this invention, ordinary epoxy resin and hydrogenated bisphenol A epoxy resin are added to the system at different stages and play different roles. Ordinary epoxy resin is mainly used for bentonite pretreatment, acting on layered fillers to improve the interlayer structure of bentonite, reduce its agglomeration tendency in subsequent processing, and improve its dispersion conditions in the polymer system. Hydrogenated bisphenol A epoxy resin is mainly used in the reactive extrusion stage, acting on reactive elastomer phases and multiphase interfaces to facilitate a more stable interfacial bond between POE, acrylic modified segments, pretreated bentonite, and the polymer matrix. The two types of epoxy resins differ in their target components, addition stages, and functions, and are not simply substitutes for each other.

[0020] Meanwhile, this invention does not employ a one-step direct blending method for each component. Instead, it first pre-treats the bentonite, then reacts and extrudes the pre-treated bentonite with POE, acrylic acid, hydrogenated bisphenol A epoxy resin, and an initiator to construct a reactive masterbatch with interfacial activity. Finally, this masterbatch is dispersed into the PVC / CPE continuous phase. This stepwise process allows the layered filler regulation, elastomer reaction, and multiphase interface construction to occur at relatively suitable stages, thereby avoiding problems such as disordered reaction pathways, uneven dispersion, and interfacial instability when components are added simultaneously.

[0021] Based on the above design, in the PVC composite system constructed in this invention, POE mainly provides toughness regulation, CPE facilitates the formation of a continuous phase synergistically with the PVC matrix, bentonite provides a certain degree of rigidity support, acrylic acid and hydrogenated bisphenol A epoxy resin jointly improve the interfacial bonding between the elastic phase and the matrix, and between the inorganic phase and the matrix, while ordinary epoxy resin is beneficial for the structural regulation of bentonite in the pretreatment stage. Thus, the material maintains good strength, modulus, and hardness during the toughening process, while also taking into account processability and insulation properties.

[0022] The beneficial effects of this invention are: (1) It is beneficial to improve the problem of increased toughness but significantly decreased rigidity in PVC toughening system: This invention combines bentonite reinforcement with elastomer toughening and uses interfacial reaction to regulate multiphase structure. While improving elongation at break and impact performance, it still maintains high tensile strength, storage modulus and Shore hardness, thereby improving the problem of significant decrease in rigidity in traditional single toughening route.

[0023] (2) It is beneficial to improve the dispersion state of layered fillers in PVC multiphase system: The present invention first pre-treats bentonite with ordinary epoxy resin, and then introduces it into PVC system through reactive extrusion and final mixing process, so that bentonite changes from the original stacked state to the intercalation expansion or partial peeling dispersion state, thereby reducing its agglomeration tendency and increasing its contribution to material rigidity and structural stability.

[0024] (3) It is beneficial to improve the interfacial bonding of multiphase systems: The present invention introduces reactive activity through acrylic acid and combines the role of hydrogenated bisphenol A epoxy resin in the reactive extrusion stage to form a more stable interfacial transition structure between the elastic phase, inorganic phase and PVC matrix; compared with one-step direct blending, the present invention is more conducive to forming a multiphase composite system with more uniform dispersion and more stable interfacial bonding.

[0025] (4) The process path is clear and suitable for industrial scale-up: The present invention adopts a step-by-step process of "bentonite pretreatment, reactive masterbatch preparation and final mixing molding". The process route is clear and can be connected with existing extrusion, granulation and molding equipment, and has good industrial implementation conditions.

[0026] (5) While maintaining comprehensive mechanical properties, processability and insulation properties are also taken into account: The PVC composite material obtained by the present invention has good melt flow capability and high volume resistivity while improving toughness and maintaining rigidity. Therefore, in addition to products with requirements for mechanical properties, it is also suitable for PVC application scenarios with certain requirements for processability and insulation properties. Attached Figure Description

[0027] Figure 1The images show the Fourier transform infrared (FTIR) spectra of different formulation samples of the present invention; where P0 is Example 1, and P1 to P8 are different control groups or variable groups. Figure 2 This is a scanning electron microscope (SEM) image of the fracture cross section of the sample. Figure 3 The following are dynamic thermomechanical analysis (DMA) curves of the samples; where (a) is the DMA curve of the PVC reference sample and (b) is the DMA curve of P0 in Example 1. Figure 4 The following are differential scanning calorimetry (DSC) curves of the samples; where (a) is the DSC curve of the PVC reference sample and (b) is the DSC curve of P0 from Example 1. Figure 5 The chart shows a comparison of the Shore D hardness of samples with different formulations; where P1 is the pure PVC sample, P2 is the PVC / CPE sample, P3 is the PVC / CPE / POE sample, and P0 is Example 1. Figure 6 The graph shows a comparison of the volume resistivity of samples with different formulations; where P1 is the pure PVC sample, P2 is the PVC / CPE sample, P3 is the PVC / CPE / POE sample, and P0 is Example 1. Figure 7 The graph shows a comparison of melt flow index (MFI, g / 10 min) for different formulation samples; where P1 is the pure PVC sample, P2 is the PVC / CPE sample, P3 is the PVC / CPE / POE sample, and P0 is Example 1. Figure 8 The image shows a comparison of water contact angles for samples with different formulations; where P1 is a pure PVC sample, P2 is a PVC / CPE sample, P3 is a PVC / CPE / POE sample, and P0 is Example 1. Figure 9 The images show X-ray diffraction (XRD) patterns of pure bentonite (Ben) and the P0 sample from Example 1; where Ben is the pure bentonite sample and P0 is Example 1. Detailed Implementation

[0028] The principles and features of this invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they should be performed according to the techniques or conditions described in the literature in this field, or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels.

[0029] Description of the source of materials and reagents: (1) Main raw materials.

[0030] The main raw materials used in the following text and their sources are shown in Table 1: Table 1. Main Raw Materials and Their Sources

[0031] PVC is the base resin; CPE is used to improve the toughening effect of the blend system; POE is the elastomer component; Ben is the layered inorganic filler; AA is used to improve the reactivity of POE; ER is used for bentonite pretreatment; and SFA is used for interface control in the reactive extrusion stage. All raw materials used in each sample were dried at 80℃ for 4–8 h before use; PVC, CPE, POE, and bentonite were dried and sealed for later use; AA, ER, and SFA were weighed according to the specified proportions before use.

[0032] (2) Main experimental equipment.

[0033] The main experimental equipment used in the following text and their sources are shown in Table 2.

[0034] Table 2. Main Instruments and Equipment and Their Sources

[0035] This embodiment relates to a PVC composite material based on in-situ reaction compatibilization and layered filler dispersion regulation, wherein the PVC composite material comprises the following components in parts by weight: 100 parts of polyvinyl chloride resin; 10-30 parts of chlorinated polyethylene; 5-15 parts of polyolefin elastomer; 1-5 parts bentonite; 0.5 to 2 parts of ordinary epoxy resin; 0.5 to 3 parts of hydrogenated bisphenol A epoxy resin; Acrylic acid 0.5 to 3 parts; Initiator 0.05 to 1 part.

[0036] In this preferred embodiment, the polyolefin elastomer is polyoctene-ethylene copolymer (POE). The initiator is at least one selected from dicumyl peroxide, benzoyl peroxide, di-tert-butyl peroxide, and azobisisobutyronitrile; the hydrogenated bisphenol A epoxy resin is a hydrogenated bisphenol A type diglycidyl ether epoxy resin. The bentonite is at least one selected from sodium-based bentonite, calcium-based bentonite, and organically modified bentonite; the ordinary epoxy resin is at least one selected from bisphenol A type epoxy resin and glycidyl ether epoxy resin.

[0037] In a preferred embodiment, the PVC composite material further includes the following components in parts by weight: 2-8 parts heat stabilizer; 0.5 to 5 parts of lubricant and / or processing aid. The heat stabilizer is at least one of calcium-zinc stabilizer and organotin stabilizer; the lubricant and / or processing aid is at least one of stearic acid, paraffin wax, oxidized polyethylene wax, and acrylate.

[0038] In this preferred embodiment, the PVC composite material comprises the following components in parts by weight: 100 parts of polyvinyl chloride resin; 15-25 parts of chlorinated polyethylene; 8-12 parts of polyolefin elastomer; 2-5 parts bentonite; 1-2 parts of ordinary epoxy resin; 1-2 parts of hydrogenated bisphenol A epoxy resin; 1-2 parts acrylic acid; Initiator 0.1–0.5 parts; Heat stabilizer 3-6 parts; 1 to 3 parts of lubricant and / or processing aid.

[0039] In this preferred embodiment, the weight ratio of the ordinary epoxy resin to the bentonite is 0.2:1 to 1:1, the weight ratio of the hydrogenated bisphenol A epoxy resin to the acrylic acid is 0.3:1 to 2:1, and the weight ratio of the chlorinated polyethylene to the polyolefin elastomer is 1.5:1 to 5:1.

[0040] This embodiment also relates to a method for preparing PVC composite materials based on in-situ reaction compatibilization and layered filler dispersion regulation, including the following steps: (1) Pretreatment: Bentonite is premixed with ordinary epoxy resin so that the ordinary epoxy resin enters the bentonite interlayer to obtain pretreated bentonite. (2) Reactive extrusion: The pretreated bentonite, polyolefin elastomer, acrylic acid, hydrogenated bisphenol A epoxy resin and initiator are added to a twin-screw extruder and reactively extruded under heating and shearing conditions to obtain reactive masterbatch; (3) Final mixing and molding: The reactive masterbatch is melt-blended with polyvinyl chloride resin and chlorinated polyethylene, and after granulation, it is molded by injection molding, extrusion or compression molding to obtain PVC composite material.

[0041] In this preferred embodiment, the premixing in step (1) is carried out using an open mill, internal mixer, or high-speed mixer, with a processing temperature of 40–120°C and a processing time of 5–30 min. In step (2), the twin-screw extruder is equipped with at least three heating zones along the material conveying direction, with temperatures of 130–150°C, 155–175°C, and 145–165°C respectively; the screw speed of the twin-screw extruder is 100–500 rpm, and an exhaust section is provided during the reactive extrusion process to remove volatiles and unreacted small molecules; wherein, polyvinyl chloride resin and chlorinated polyethylene are not added in step (2); polyvinyl chloride resin and chlorinated polyethylene are added in step (3) for melt blending so that the reactive masterbatch is dispersed in the continuous polyvinyl chloride phase; In step (3), melt blending is carried out using a kneader or a twin-screw extruder; the blending temperature of melt blending is 160-180℃, and the blending time is 3-15 min.

[0042] This embodiment also relates to the application of PVC composite materials based on in-situ reaction compatibilization and layered filler dispersion regulation. The PVC composite materials based on in-situ reaction compatibilization and layered filler dispersion regulation are used in the preparation of outdoor building materials, wire and cable sheaths, door and window profiles, outdoor panels, insulating structural components or high impact-resistant structural components.

[0043] To further verify the present invention, a series of samples from P0 to P8 were set up as shown in Table 3 to investigate the effects of SFA, AA, Ben and ER on the material structure and properties, as well as the differences between the one-step method and the stepwise method in terms of component dispersion and interface state.

[0044] Table 3. Formulation Composition Table for P0~P8

[0045] From an experimental perspective, P1, P2, and P3 were used to establish the performance baseline of the traditional system; P4 was used to examine the performance changes of the system after removing SFA, thereby evaluating the role of hydrogenated epoxy in network construction and interface regulation; P5 was used to analyze the role of AA in POE functionalization; P6 was used to analyze the role of Ben in maintaining and enhancing rigidity; P7 was used to analyze the role of ER in Ben pretreatment; and P8 was used to verify the limitations of one-step direct physical blending.

[0046] P0 is Example 1, which is used to comprehensively investigate the effects of conventional epoxy resin pretreatment of bentonite, introduction of acrylic acid, participation of hydrogenated bisphenol A epoxy resin in reactive extrusion, and stepwise process on the material structure and properties.

[0047] The specific embodiments and comparative examples used below further illustrate the present invention.

[0048] Example 1: (P0) In this embodiment, 50 g of PVC, 10 g of CPE, 5 g of POE, 1 g of SFA, 2 g of Ben, 1 g of ER, and 1 g of AA were weighed, and appropriate amounts of initiator, heat stabilizer, lubricant, and processing aid were added. The mixture was then prepared according to the following steps: (1) Ben preprocessing: Add 2 g Ben and 1 g ER to a benchtop internal mixer and mix at 80–100 °C for 5–10 min to obtain a pretreated mixture.

[0049] (2) Preparation of masterbatch by reactive extrusion: The pretreated Ben, POE, AA, SFA and initiator are added to a twin-screw extruder and reactive extrusion is carried out in the temperature range of 130 to 175°C, with the screw speed controlled at 100 to 500 rpm to obtain reactive masterbatch.

[0050] (3) Final mixing and molding: The reactive masterbatch is added to an open mill or internal mixer with PVC, CPE and other additives, and melt-mixed at 160-180°C for 3-15 minutes. After granulation, standard test strips are obtained by injection molding or compression molding, which is PO.

[0051] Experimental results show that the sample has higher elongation at break and notched impact strength than P1, P2, P3 and P4, while maintaining high tensile strength and storage modulus. This indicates that the multiphase structure constructed by the stepwise process helps to balance toughness improvement and rigidity maintenance, and improves the interface state and structural stability of the system.

[0052] Comparative Example 1: Pure PVC baseline group (P1) Weigh 100 parts of PVC resin and add conventional heat stabilizers, lubricants and processing aids. After high-speed mixing, the mixture is plasticized on an open two-roll mill and then obtained through a micro all-electric injection molding machine as standard tensile specimens, notched impact specimens and DMA and DSC test pieces, denoted as P1.

[0053] P1 is the unmodified baseline group, whose main function is to establish a reference for the intrinsic properties of pure PVC materials. The results show that pure PVC has high tensile strength and high hardness, but low elongation at break and notched impact strength, exhibiting typical hard-brittle characteristics. Its fracture surface is relatively smooth with few traces of plastic deformation, indicating that pure PVC mainly fails through brittle fracture under external forces. This provides an initial benchmark for subsequent comparisons between traditional toughening systems and the synergistically reinforced toughening system of this invention.

[0054] Comparative Example 2: Traditional CPE toughened group (P2) Weigh 50 g of PVC and 10 g of CPE, add conventional heat stabilizers, lubricants and processing aids, premix and then plasticize on a two-roll mill, and then injection mold to obtain a standard sample, denoted as P2.

[0055] This comparative example is used to simulate a traditional PVC / CPE toughening system. Compared to P1, group P2 shows improved elongation at break and notched impact strength, indicating that CPE can improve the brittleness of PVC; however, its tensile strength decreases, and the material hardness and modulus also decrease. This suggests that while the traditional CPE toughening route can improve toughness, it also weakens the material's rigidity and strength. From a materials design perspective, P2 represents a common toughening scheme in traditional industry, and is therefore suitable as a comparison of the technical effects of this invention.

[0056] Comparative Example 3: Traditional CPE / POE co-toughening group (P3) Weigh 50 g of PVC, 10 g of CPE and 5 g of POE, add conventional heat stabilizers and processing aids, mix at high speed and then plasticize in an open mill, and injection mold to obtain test strips, denoted as P3.

[0057] This comparative example is used to simulate a traditional multi-elastomer co-toughening system. Compared to P2, P3 shows further improvements in elongation at break and notched impact strength, indicating that the introduction of POE enhances the material's energy dissipation and deformation capacity. However, due to the low polarity of POE, the interfacial interaction with the PVC matrix is ​​limited, resulting in a further decrease in tensile strength, and more pronounced phase separation characteristics are usually visible on the fracture surface. Therefore, P3 demonstrates that while simply adding a flexible phase can further improve toughness, without effective compatibility and interfacial control methods, the material's strength retention capacity will further decline. This is one of the reasons why this invention introduces AA, ER, SFA, and Ben and employs a stepwise process.

[0058] Comparative Example 4: Reaction system lacking SFA (P4) Weigh out 50 g of PVC, 10 g of CPE, 5 g of POE, 2 g of Ben, 1 g of ER, and 1 g of AA, and add appropriate amounts of initiator and processing aids. First, allow POE to undergo a grafting reaction with AA under the action of the initiator, while simultaneously allowing Ben and ER to participate in premixing or blending treatment to obtain intermediate masterbatch; then, finally mix the masterbatch with PVC and CPE and form it, denoted as P4.

[0059] This comparative example examines the changes in system structure and performance when relying solely on AA grafting, ER pretreatment, and Ben reinforcement without the introduction of SFA. Experimental results show that P4 exhibits better overall performance compared to P2 and P3, with improvements in tensile strength, elongation at break, and impact strength. This indicates that AA imparts reactivity to POE, helping to improve the interfacial state between POE and PVC; simultaneously, ER pretreatment of Ben also facilitates its dispersion in the system. However, P4 still differs from P0, indicating that AA and ER alone are insufficient to achieve the interfacial state corresponding to P0, and SFA still plays a role in further improving structural stability during the reactive extrusion stage.

[0060] Comparative Example 5: Reaction system lacking AA (P5) Weigh out 50 g PVC + 10 g CPE + 5 g POE + 2 g Ben + 1 g ER + 1 g SFA, and add appropriate amounts of initiator and processing aids, denoted as P5. The preparation steps are the same as described in Example 1, except for the following steps: (2) Preparation of masterbatch by reactive extrusion: The pretreated Ben, POE, SFA and initiator are added to a twin-screw extruder and reactive extrusion is carried out in the temperature range of 130 to 175°C, with the screw speed controlled at 100 to 500 rpm, to obtain reactive masterbatch.

[0061] P5 is used to analyze the role of AA in POE functionalization.

[0062] Comparative Example 6: Reaction system lacking bentonite (P6) Weigh out 50 g of PVC, 10 g of CPE, 5 g of POE, 1 g of SFA, 1 g of ER, and 1 g of AA, and add an initiator and conventional additives, but do not add Ben. The preparation steps are the same as those described in Example 1, except for the following steps: first, perform a reaction grafting of POE and AA, and then involve SFA in the reactive extrusion process, followed by final mixing with PVC and CPE to form a compound, denoted as P6.

[0063] This comparative example was used to analyze the role of Ben in this invention. The results show that P6 still exhibits a high elongation at break, indicating that AA grafting and SFA participation in the reaction contribute to improved toughness; however, compared to P0, its tensile strength, hardness, and DMA storage modulus are all lower, indicating that Ben plays a crucial role in maintaining rigidity in the system of this invention. This result suggests that Ben not only exists as a filler in this invention but is also related to interface regulation and structural support. P6 is mainly used to illustrate the influence of bentonite on the material's strength, modulus, and rigidity maintenance.

[0064] Weigh 50 g PVC + 10 g CPE + 5 g POE + 2 g Ben + 1 g SFA + 1 g AA, without adding ER; the preparation steps are the same as those described in Example 1 except for the following steps: no Ben pretreatment is performed; denoted as P7.

[0065] P7 is used to analyze the role of ER in Ben pretreatment.

[0066] Comparative Example 8: One-step direct blending Weigh out 50 g PVC + 10 g CPE + 5 g POE + 2 g Ben + 1 g ER + 1 g SFA + 1 g AA. For the physical blend control sample, add all raw materials to the mixing equipment at once for premixing, then directly perform melt blending and granulation, and obtain the sample by injection molding or compression molding, denoted as P8.

[0067] P8 was used to verify the limitations of one-step direct physical blending.

[0068] Experimental example: (1) Mechanical property analysis: To highlight the key effects of the present invention, P1, P2, P3, P4, P6, P7, P8 and P0 were selected as representative samples for performance comparison, and the results are shown in Table 4.

[0069] Table 4 Comparison of Mechanical Properties of Representative Groups

[0070] Note: The data in the table are mean ± standard deviation, and the number of parallel tests n = 5.

[0071] Table 4 shows that P1 exhibits typical high strength and low toughness characteristics, with high tensile strength but low elongation at break and notched impact strength, indicating that pure PVC material is rigid but lacks toughness. After introducing CPE, the elongation at break and notched impact strength of P2 are significantly improved, indicating that CPE can improve the brittleness of PVC to a certain extent, but its tensile strength decreases, indicating that traditional elastomer toughening is usually accompanied by a loss of strength and rigidity.

[0072] After further introducing POE into P3 based on P2, the elongation at break and notched impact strength continued to increase, indicating that the increased content of the flexible phase further enhanced the material's plastic deformation capacity and impact energy dissipation capacity. However, its tensile strength continued to decrease, indicating that while relying solely on multi-elastomer blending can improve toughness, it easily leads to insufficient interfacial interaction in the system, thereby weakening the strength retention capacity. This reflects the typical problem of "increased toughness but decreased strength" in traditional PVC / CPE / POE multiphase toughening systems.

[0073] P4 is the sample obtained by removing SFA from P0. Compared with P2 and P3, P4 shows further improvement in tensile strength, elongation at break, and notched impact strength, indicating that the system has formed a certain reactive compatibilization and reinforcing support structure after the introduction of AA, ER, and Ben; however, the overall performance of P4 is still lower than that of P0, indicating that without the participation of SFA, the degree of interfacial reaction and structural stability of the system are still limited, making it difficult to achieve the synergistic effect formed by the complete system.

[0074] P6 is the sample obtained by removing Ben from P0. Its elongation at break remains at a high level, indicating that AA and SFA are still effective in regulating the flexible phase interface and improving toughness after participating in the reaction; however, its tensile strength and notched impact strength are lower than P0, indicating that Ben not only acts as a filler in the system of this invention, but also makes an important contribution to structural support, strength recovery and toughness-stiffness balance.

[0075] P7 is the sample obtained by removing ER from P0. Compared with P0, P7 shows a decrease in tensile strength, elongation at break, and notched impact strength, indicating that the dispersion conditions and interfacial bonding state of bentonite in the system are adversely affected when ER is not used for pretreatment of Ben, making it difficult to fully exert its reinforcing and synergistic effects. This suggests that ER is not a simple additive in this invention, but plays a positive role in the structural regulation and subsequent performance improvement of bentonite.

[0076] Sample P8 is a sample with a composition similar to P0 but prepared by direct blending in a one-step process. Its tensile strength, elongation at break, and notched impact strength are all lower than P0, indicating that even with similar formulations, it is difficult to achieve the same microstructure and interfacial structure as P0 without step-by-step process control of "pretreatment—reactive extrusion—final blending and molding." This result demonstrates that in multi-component PVC composite systems, the process sequence has a significant impact on material structure formation and performance improvement.

[0077] In summary, P0 exhibits significantly higher elongation at break and notched impact strength than P2, P3, P4, P6, P7, and P8, while maintaining high tensile strength. This indicates that the component combination and stepwise process employed in this invention are beneficial for improving the dispersion state of bentonite and the interphase interface bonding, thereby enabling the material to maintain a good strength level while improving toughness. These results demonstrate that the configuration of different components and the process sequence significantly affect the structure and properties of the PVC composite system, and the stepwise construction method adopted in this invention is conducive to achieving a better balance between toughness and strength.

[0078] (2) FTIR results and discussion: To analyze the changes in functional groups in the system and verify the possibility of the introduction of acrylic acid and the participation of epoxy groups in the reaction, Fourier transform infrared spectroscopy was performed on samples P1, P4, P8, and P0. The results are as follows: Figure 1 As shown.

[0079] The infrared spectrum of pure PVC sample P1 mainly exhibits the intrinsic absorption characteristics of PVC, in the range of 1720–1730 cm⁻¹. 1 No obvious carbonyl characteristic absorption peaks were observed nearby. Compared with P1, sample P4 showed a more pronounced absorption peak in the 1720–1730 cm⁻¹ range. 1 The presence of a relatively obvious absorption peak nearby indicates the introduction of a carbonyl-containing structure into the system, suggesting that acrylic acid has participated in the composite system. Meanwhile, P4 shows an absorption peak in the 910–915 cm⁻¹ range. 1 Some epoxy-related absorption characteristics can still be observed nearby, indicating that epoxy groups in the system participated in the reaction, but some epoxy groups were not completely consumed.

[0080] Sample P8 also exhibited absorption changes related to carbonyl and epoxy groups, indicating that functional group reactions can occur to some extent under one-step blending conditions. However, due to the simultaneous addition of all components to the system, the reaction pathway and contact conditions are more complex, and its characteristic absorption changes are not as obvious as those of sample P0, suggesting that the orderliness of the reaction and interface construction under one-step conditions is relatively insufficient.

[0081] P0 samples were at 1720–1730 cm⁻¹ 1 The carbonyl absorption peaks are more pronounced in the vicinity, while those at 910–915 cm⁻¹ are more pronounced. 1 The characteristic absorption of nearby epoxy groups is further weakened, while the absorption at 3200–3600 cm⁻¹ is also weakened. 1 The regional hydroxyl peaks were enhanced. These changes indicate that, under the stepwise process conditions employed in this invention, the introduction of acrylic acid, ring-opening of epoxy groups, and related interfacial reactions are more readily achieved, thereby facilitating the formation of more interfacial binding sites between the polyolefin elastomer, bentonite, and the polymer matrix.

[0082] Based on the preparation process of this invention, it can be considered that pretreating bentonite with ordinary epoxy resin is beneficial to improving the dispersion conditions of bentonite in subsequent systems; during the reactive extrusion stage, acrylic acid, hydrogenated bisphenol A epoxy resin, and polyolefin elastomer further react, giving the resulting masterbatch high reactivity; finally, during the final mixing process, the above-mentioned reactive components are dispersed in the PVC continuous phase, which is beneficial to improving the interfacial bonding of the multiphase system. The FTIR results are consistent with the process design of this invention, indicating that the technical solution of this invention has a corresponding chemical reaction basis.

[0083] (3) SEM results and analysis: Scanning electron microscopy was used to observe the liquid nitrogen brittle fracture surfaces of different samples P1, P4, P8, and P0 to analyze their fracture morphology, filler dispersion state, and interfacial bonding. The results are as follows: Figure 2 As shown.

[0084] The cross-section of pure PVC sample P1 is relatively flat, exhibiting a typical brittle fracture morphology. Few obvious traces of plastic deformation were observed on the cross-section, indicating that pure PVC mainly exhibits brittle failure characteristics during stress failure.

[0085] A certain number of lamellar or granular structures can be observed in the cross-section of sample P4, indicating that the internal structure of the system has changed compared to pure PVC after the introduction of AA, ER, and Ben. The material can undergo certain plastic deformation and dissipate the energy of external forces during fracture. However, from the local morphology, there is still uneven dispersion in the system, indicating that there is still room for further improvement in filler dispersion and interfacial state under the condition of lacking SFA to participate in the interfacial reaction.

[0086] Because the P8 sample was directly blended in one step, all components entered the system at the same stage, and the reaction, dispersion and interface construction processes were carried out simultaneously. The cross-section showed obvious lamellar exposure, agglomeration and interface discontinuity, indicating that in a multi-component system, it is difficult to obtain a stable and uniform microstructure by relying solely on one-step direct blending.

[0087] In contrast, the P0 sample has a rougher overall cross-section, with more obvious plastic tearing, pores, and irregular undulating structures, indicating that the material can dissipate energy through more plastic deformation during fracture. Based on the local morphology, it can be concluded that the step-by-step process of bentonite pretreatment, reactive extrusion to prepare masterbatch, and final mixing and molding adopted in this invention is beneficial to improving the dispersion state and interfacial bonding between the inorganic phase and the polymer matrix in a multiphase system.

[0088] Based on the mechanical property results, it can be concluded that the P0 sample dissipates energy through multiple mechanisms during fracture, including interfacial debonding, plastic tearing, and local shear yielding, thus exhibiting good toughness. Simultaneously, the relatively uniform dispersion of bentonite within the system provides necessary rigid support. The SEM results thus demonstrate that the process of this invention is beneficial for constructing a relatively stable multiphase dispersion structure.

[0089] (4) DMA Results and Analysis: Dynamic thermomechanical analysis was used to test the changes in storage modulus and loss factor of samples P1 and P0 with temperature, in order to evaluate the material's rigidity retention and structural stability. The results are as follows: Figure 3 As shown in (a) and (b).

[0090] The pure PVC sample P1 has a high storage modulus near room temperature, indicating that its matrix has high rigidity; at the same time, its loss peak is relatively concentrated, reflecting that the material has a relatively limited energy dissipation mode under external force, which is typical of hard and brittle materials.

[0091] Compared with P1, the P0 sample showed a more obvious loss response in the low temperature region, indicating that the material still has a certain energy dissipation capacity at low temperatures; at the same time, it still maintains a high energy storage modulus in the room temperature and medium-high temperature regions, indicating that the material of the present invention still has good structural support capacity while improving toughness.

[0092] Combining the mechanical properties and SEM results, it can be concluded that the higher storage modulus retention capacity of the P0 sample corresponds to a more uniform phase structure and a more stable interface state. The DMA results thus demonstrate that the stepwise process employed in this invention is beneficial for improving the dynamic mechanical behavior and structural stability of the PVC composite system.

[0093] (5) DSC Results and Analysis: To analyze the thermal transformation behavior and thermal response characteristics of the samples, differential scanning calorimetry (DSC) was performed on samples P1 and P0. The results are as follows: Figure 4 As shown in (a) and (b).

[0094] The pure PVC sample P1 exhibits typical thermal transition characteristics of the PVC matrix, indicating that its system composition is relatively simple.

[0095] Compared with P1, the P0 sample showed a more gradual change in heat flow and better baseline continuity in the thermal transition region. This indicates that the process sequence of bentonite pretreatment, reactive extrusion to prepare masterbatch and final mixing adopted in this invention is beneficial to improving the dispersion state and interfacial bonding of each component in the multiphase system, thereby making the overall thermal response of the material more stable.

[0096] Combining DMA and SEM results, it can be further concluded that the relatively smooth thermal transition behavior of the P0 sample corresponds to its relatively uniform phase structure and relatively stable interface state. The DSC results thus demonstrate that the technical solution of this invention is beneficial for improving the structural uniformity and thermal stability of the PVC multiphase composite system.

[0097] (6) Shore hardness analysis: To evaluate the material's ability to retain apparent stiffness after toughening modification, Shore D hardness tests were performed on different samples P1, P2, P3, and P0. The results are as follows: Figure 5 As shown.

[0098] The pure PVC sample P1 exhibits a high Shore hardness, displaying typical characteristics of a rigid material. The Shore hardness of the traditional PVC / CPE system P2 is lower than that of P1, indicating that the apparent rigidity of the material decreases after toughening with CPE. Further addition of POE results in a continued decrease in the Shore hardness of P3, suggesting that the system's resistance to indentation weakens further with increasing proportions of flexible phase.

[0099] In contrast, the Shore hardness of P0 in Example 1 was significantly higher than that of P2 and P3, and close to that of pure PVC sample P1. This result indicates that the present invention does not improve toughness solely by introducing elastic components, but rather demonstrates that the material maintains high apparent rigidity through the dispersion enhancement of bentonite and the regulation of interfacial structure during the toughening process.

[0100] Based on the XRD, SEM, and DMA results, the good hardness retention of the P0 sample can be attributed to two main factors: firstly, the increased dispersion of bentonite after pretreatment with ordinary epoxy resin and subsequent extrusion facilitates the formation of rigid support points within the matrix; secondly, the interfacial reaction involving hydrogenated bisphenol A epoxy resin improves the interphase bonding, helping to limit excessive local deformation of the flexible phase under pressure. Therefore, the P0 sample exhibits better rigidity retention than traditional toughening systems.

[0101] (7) Volume resistivity analysis: To evaluate the electrical insulation properties of different formulation samples, volume resistivity tests were performed on P1, P2, P3, and P0. The results are as follows: Figure 6 As shown.

[0102] Test results show that all samples maintained the high insulation properties of PVC material, indicating that the toughening components, epoxy resin and bentonite used in this invention did not significantly damage the original electrical insulation properties of the PVC matrix.

[0103] The pure PVC sample P1 has a high volume resistivity, which is consistent with the general characteristics of rigid PVC insulation materials. In P2 and P3, due to the introduction of flexible components such as CPE and POE, the number of interfaces inside the system increases, and the local chain segment mobility changes. The volume resistivity changes compared to P1, but it still remains at a high level overall.

[0104] The P0 in Example 1 maintains good mechanical and processing properties while still exhibiting a high volume resistivity. This result indicates that the multiphase composite structure constructed by bentonite pretreatment, reactive extrusion, and final mixing in this invention does not form a significant conductive pathway. Combined with the structural analysis results, it can be concluded that the layered structure of bentonite and the relatively stable interfacial bonding are beneficial in maintaining the integrity of the internal structure of the system, thereby ensuring that the material retains good insulation properties.

[0105] Therefore, the volume resistivity test results show that the material of the present invention is not only suitable for structural applications requiring mechanical properties, but also for PVC products requiring certain insulation properties.

[0106] (8) Melt index analysis: To evaluate the melt flowability and processing adaptability of the materials, melt flow index tests were performed on different samples P1, P2, P3, and P0. The results are as follows: Figure 7 As shown.

[0107] The pure PVC sample P1 has a low melt flow index, indicating relatively weak melt flowability and a narrow processing window. The traditional toughening system P2 has a higher melt flow index than P1, suggesting that the introduction of CPE improves the material's processing flowability to some extent.

[0108] After further introducing POE, the melt index of P3 was still higher than that of P1, but it did not continue to increase compared to P2. This indicates that in the absence of effective interface control, the addition of POE does not necessarily continuously improve the melt flow performance. Factors such as multiphase interface instability and chain segment entanglement may affect the flow behavior.

[0109] In contrast, the melt flow index of P0 in Example 1 is significantly higher than that of P1, P2, and P3, indicating that the material of the present invention has better melt flowability. This result demonstrates that the present invention achieves an ordered multi-component structure through a stepwise process: pretreated bentonite is more readily dispersed in the system; the introduction of acrylic acid enhances the reactivity of the polyolefin elastomer; and the participation of hydrogenated bisphenol A epoxy resin in the interfacial reaction improves the multiphase interfacial state, thereby enabling the material to exhibit good processability while maintaining structural stability.

[0110] Therefore, it can be seen that the material of the present invention not only has a good overall balance in terms of mechanical properties, but also has good application adaptability in common processing methods such as injection molding, extrusion and compression molding.

[0111] (9) Water contact angle analysis: To investigate the changes in material surface wettability, water contact angle tests were conducted on different samples, and the results are as follows: Figure 8 As shown.

[0112] The water contact angle of pure PVC sample P1 is at a moderate level, exhibiting some hydrophobicity. After the introduction of CPE, the water contact angle of P2 increases, indicating a change in the material's surface wettability. Further addition of POE causes the water contact angle of P3 to continue increasing, suggesting that the introduction of the non-polar flexible phase has a certain influence on the material's surface wetting behavior.

[0113] In Example 1, the water contact angle of P0 is higher than that of P1, P2, and P3, indicating that the surface hydrophobicity of the material of the present invention is further improved. Considering the system composition and structural characteristics, this result can be attributed to the following factors: on the one hand, the introduction of CPE and POE has a regulating effect on the surface polarity of the material; on the other hand, interfacial reactions and bentonite dispersion improve the surface and near-surface structural state of the material, thereby affecting surface wettability.

[0114] An increased water contact angle indicates that the material surface is less susceptible to water wetting, which is beneficial for improving the material's moisture resistance and surface stability during use. Therefore, in addition to possessing good mechanical and processing properties, the material of this invention also has certain surface performance application value in applications such as door and window profiles, panels, and insulating sleeves.

[0115] Table 5 Shore hardness, volume resistivity, melt flow index, and water contact angle of different samples

[0116] Table 5 shows that P1 has high Shore hardness and volume resistivity, but low melt flow index; P2 and P3 show a decrease in Shore hardness after toughening, with P3 showing a further decrease in volume resistivity. In contrast, P0 from Example 1 maintains high Shore hardness and volume resistivity while exhibiting a large melt flow index and a high water contact angle, indicating that the material of this invention has a good overall balance in terms of rigidity, insulation performance, processability, and surface wettability. This result further illustrates that the present invention, through the process sequence control of bentonite pretreatment, reactive masterbatch construction, and final mixing, can improve the interfacial bonding and component dispersion of multiphase systems.

[0117] (10) XRD analysis: To analyze the changes in the interlayer structure of bentonite in the composite system, XRD tests were performed on pure bentonite Ben and P0 samples. The results are as follows: Figure 9 As shown, pure bentonite (Ben) exhibits distinct characteristic diffraction peaks in the low-angle region, indicating a relatively regular layered stacked structure. In contrast, the characteristic peaks corresponding to the layered structure of bentonite in the P0 sample weaken and tend to broaden, indicating a reduced interlayer order in the bentonite within the system of this invention, exhibiting a dispersion trend of intercalation expansion or partial exfoliation. This result demonstrates that pretreatment with ordinary epoxy resin combined with subsequent reactive extrusion can improve the dispersion state of bentonite in the PVC composite system and influence the material's rigidity retention and overall mechanical properties.

[0118] In summary, based on the results of mechanical properties, FTIR, SEM, DMA, DSC, Shore hardness, volume resistivity, melt flow index, water contact angle, and XRD tests, it can be seen that the configuration and process sequence of different components in this invention affect the structure and properties of the PVC composite system. The mechanical properties, DMA, and Shore hardness results show that while the traditional PVC / CPE and PVC / CPE / POE systems can improve material toughness, they cause a decrease in tensile strength, storage modulus, and apparent hardness. In contrast, the PO of Example 1 maintains high tensile strength and Shore hardness while improving elongation at break and impact performance, indicating that the multiphase structure formed under stepwise process conditions helps to balance toughness improvement and rigidity maintenance. The FTIR, SEM, DMA, and DSC results show that pretreatment of bentonite with ordinary epoxy resin helps improve the dispersion conditions of bentonite in subsequent systems; acrylic acid, under the action of an initiator, improves the reactivity of polyolefin elastomers; and the participation of hydrogenated bisphenol A epoxy resin in the reactive extrusion process helps improve the multiphase interface state. Correspondingly, the P0 sample exhibited a more continuous cross-sectional morphology, a more stable dynamic mechanical response, and a smoother thermal transition behavior, indicating that the process has a positive effect on the uniformity of the microstructure and the structural stability of the multiphase system. XRD results showed that after pretreatment with ordinary epoxy resin and subsequent reactive extrusion, the characteristic peaks of the layered structure of bentonite weakened and broadened, indicating that its dispersion in the composite system was improved. Combined with SEM observations, it can be considered that the process of this invention helps bentonite play a rigid supporting role in the material, which is one of the reasons why the P0 sample still maintains high hardness and modulus under toughening conditions. Furthermore, a comparison between P8 and P0 shows that, with similar component compositions, different process sequences lead to different structural and performance results. This result indicates that in multi-component systems, the process sequence affects the formation of the material structure. The melt flow index results show that the melt flow capacity of P0 is higher than that of the traditional control sample, indicating that this invention maintains good processability while improving mechanical properties. Combined with the volume resistivity results, it can be seen that the introduction of multiple components and the reactive extrusion process did not significantly damage the original insulation properties of the PVC matrix. The water contact angle test results show that the surface wettability of the material obtained by the present invention changes, which has certain application significance in terms of moisture protection and surface stability.

[0119] In summary, this invention improves the component dispersion and interfacial state of the PVC composite system by pretreating bentonite with ordinary epoxy resin, participating in reactive extrusion with hydrogenated bisphenol A epoxy resin, and incorporating the introduction of acrylic acid and final mixing and dispersion with reactive masterbatch. This results in materials exhibiting better overall performance. The PVC composite material prepared using this invention can be used in the fields of door and window profiles, sheets, wire and cable sheaths, insulating structural components, and PVC products requiring certain impact resistance and structural support capabilities.

[0120] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A PVC composite material based on in-situ reaction compatibilization and layered filler dispersion regulation, characterized in that, The PVC composite material comprises the following components in parts by weight: 100 parts of polyvinyl chloride resin; 10-30 parts of chlorinated polyethylene; 5-15 parts of polyolefin elastomer; 1-5 parts bentonite; 0.5 to 2 parts of ordinary epoxy resin; 0.5 to 3 parts of hydrogenated bisphenol A epoxy resin; Acrylic acid 0.5 to 3 parts; Initiator 0.05 to 1 part.

2. The PVC composite material based on in-situ reaction compatibilization and layered filler dispersion regulation according to claim 1, characterized in that, The polyolefin elastomer is a polyoctene-ethylene copolymer; The initiator is at least one of dicumyl peroxide, benzoyl peroxide, di-tert-butyl peroxide, and azobisisobutyronitrile; The hydrogenated bisphenol A epoxy resin is a hydrogenated bisphenol A type diglycidyl ether epoxy resin.

3. The PVC composite material based on in-situ reaction compatibilization and layered filler dispersion regulation according to claim 1, characterized in that, The bentonite is at least one of sodium-based bentonite, calcium-based bentonite, and organically modified bentonite. The common epoxy resin is at least one of bisphenol A type epoxy resin and glycidyl ether type epoxy resin.

4. The PVC composite material based on in-situ reaction compatibilization and layered filler dispersion regulation according to claim 1, characterized in that, The PVC composite material also includes the following components in parts by weight: 2-8 parts heat stabilizer; 0.5 to 5 parts of lubricant and / or processing aid.

5. The PVC composite material based on in-situ reaction compatibilization and layered filler dispersion regulation according to claim 4, characterized in that, The heat stabilizer is at least one of calcium-zinc stabilizer and organotin stabilizer; The lubricant and / or processing aid is at least one of stearic acid, paraffin wax, oxidized polyethylene wax, and acrylate.

6. The PVC composite material based on in-situ reaction compatibilization and layered filler dispersion regulation according to claim 1, characterized in that, The weight ratio of the ordinary epoxy resin to the bentonite is 0.2:1 to 1:1, the weight ratio of the hydrogenated bisphenol A epoxy resin to the acrylic acid is 0.3:1 to 2:1, and the weight ratio of the chlorinated polyethylene to the polyolefin elastomer is 1.5:1 to 5:

1.

7. A method for preparing PVC composite materials based on in-situ reaction compatibilization and layered filler dispersion control according to any one of claims 1 to 6, characterized in that, The steps include the following: (1) Pretreatment: Bentonite is premixed with ordinary epoxy resin so that the ordinary epoxy resin enters the bentonite interlayer to obtain pretreated bentonite. (2) Reactive extrusion: The pretreated bentonite, polyolefin elastomer, acrylic acid, hydrogenated bisphenol A epoxy resin and initiator are added to a twin-screw extruder and reactively extruded under heating and shearing conditions to obtain reactive masterbatch; (3) Final mixing and molding: The reactive masterbatch is melt-blended with polyvinyl chloride resin and chlorinated polyethylene, and after granulation, it is molded by injection molding, extrusion or compression molding to obtain PVC composite material.

8. The method for preparing PVC composite material based on in-situ reaction compatibilization and layered filler dispersion control according to claim 7, characterized in that, The premixing in step (1) is carried out using an open mill, internal mixer or high-speed mixer, with a processing temperature of 40 to 120°C and a processing time of 5 to 30 minutes.

9. The method for preparing PVC composite material based on in-situ reaction compatibilization and layered filler dispersion regulation according to claim 7, characterized in that, In step (2), the twin-screw extruder is equipped with at least three heating zones along the material conveying direction, with the temperatures of each heating zone being 130-150℃, 155-175℃ and 145-165℃ respectively, and the screw speed of the twin-screw extruder being 100-500 rpm; In step (3), melt blending is carried out using a kneader or a twin-screw extruder; the blending temperature of melt blending is 160-180℃, and the blending time is 3-15 min.

10. The application of PVC composite materials based on in-situ reaction compatibilization and layered filler dispersion regulation, characterized in that, The PVC composite material based on in-situ reaction compatibilization and layered filler dispersion regulation as described in any one of claims 1 to 6 is used in the preparation of outdoor building materials, wire and cable sheaths, door and window profiles, outdoor panels, insulating structural components or high-impact structural components.

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