A high-strength, high-weather-resistant polyvinyl chloride composite material and its preparation method

Abstract

This application discloses a high-strength, high-weather-resistant polyvinyl chloride (PVC) composite material and its preparation method, relating to the field of polymer materials technology. Graft-modified PVC is obtained by reacting 4-aminobenzoic acid ester compounds with PVC. The graft-modified PVC is then thoroughly mixed with inorganic fillers, plasticizers, stabilizers, lubricants, and antioxidants under specific formulation and processes to obtain a high-strength, high-weather-resistant PVC composite material. This PVC composite material possesses both high strength and excellent weather resistance, enabling it to withstand various demanding application environments and demonstrating promising application prospects.

Description

Technical Field

[0001] This application relates to the field of polymer materials technology, and in particular to a high-strength, high-weather-resistant polyvinyl chloride composite material and its preparation method. Background Technology

[0002] Polyvinyl chloride (PVC), as one of the five major general-purpose plastics, has been widely used in many fields such as construction, automobiles, packaging, and electrical engineering due to its advantages such as low cost, high plasticity, and good chemical stability. However, with increasingly complex and diversified application scenarios, especially in environments with stringent material performance requirements, the limitations of traditional PVC materials are becoming increasingly apparent. On the one hand, in terms of mechanical properties, the tensile strength and flexural strength of ordinary PVC materials are relatively limited, making it difficult to meet the high-strength requirements of some applications. On the other hand, weather resistance has become a key bottleneck restricting the outdoor application of PVC. In outdoor environments, PVC materials are continuously exposed to the combined effects of ultraviolet radiation, temperature changes, humidity fluctuations, and atmospheric pollutants (such as acid rain and ozone). Often, they need to be replaced within a short period due to poor weather resistance, resulting in significant resource waste and maintenance costs.

[0003] Therefore, developing a polyvinyl chloride composite material that combines high strength and high weather resistance with a reasonable and feasible preparation process has become a key technical challenge that urgently needs to be addressed in the field of plastic materials. This is of great significance for promoting the upgrading of the PVC industry and expanding its application scope.

[0004] Chinese patent application CN115612224A discloses a polyvinyl chloride composite material and its preparation method. The polyvinyl chloride composite material is prepared by weight of 100-200 parts of polyvinyl chloride, 50-100 parts of high-density polyethylene, 10-30 parts of maleic anhydride-grafted high-density polyethylene, 5-15 parts of a first weathering agent and 0.5-1 parts of a second weathering agent. The first weathering agent is carbon black and the second weathering agent is antioxidant ZKF.

[0005] However, the above technical solution does not modify or optimize the polyvinyl chloride (PVC) as the main component; it simply physically combines the components directly, and the resulting PVC composite material still has considerable room for improvement in terms of strength and weather resistance. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this application provides a high-strength, high-weather-resistant polyvinyl chloride (PVC) composite material and its preparation method. Graft-modified PVC is obtained by reacting 4-aminobenzoic acid ester compounds with PVC. The graft-modified PVC is then thoroughly mixed with inorganic fillers, plasticizers, stabilizers, lubricants, and antioxidants under specific formulation and processing conditions to obtain a high-strength, high-weather-resistant PVC composite material.

[0007] To achieve the above objectives, this application adopts the following technical solution:

[0008] In a first aspect, this application provides a high-strength, high-weather-resistant polyvinyl chloride composite material, comprising graft-modified polyvinyl chloride; wherein the graft-modified polyvinyl chloride is obtained by reacting a 4-aminobenzoic acid ester compound with polyvinyl chloride; wherein the 4-aminobenzoic acid ester compound comprises any one of n-propyl 4-aminobenzoate, isopropyl 4-aminobenzoate, n-butyl 4-aminobenzoate, isobutyl 4-aminobenzoate, and 2-ethylhexyl 4-aminobenzoate.

[0009] Secondly, this application provides a method for preparing a high-strength, high-weather-resistant polyvinyl chloride composite material, comprising the following steps:

[0010] Polyvinyl chloride (PVC) was added to DMF, and under nitrogen protection, the temperature was raised to 70–90°C. Then, 4-aminobenzoic acid esters and Lewis acid were added, and the mixture was stirred and reacted for 4–6 hours. The product was precipitated, washed, and dried to obtain grafted PVC.

[0011] Weigh the grafted modified polyvinyl chloride, inorganic filler, plasticizer, stabilizer, lubricant and antioxidant, add them to a high-speed mixer, mix at 80-100℃ for 10-20 minutes, cool and discharge to obtain the premix;

[0012] Add the premix to an internal mixer and mix at 160–180°C and 30–50 rpm for 5–15 minutes to obtain the mixture.

[0013] The compound is calendered using a four-roll calender at a roll temperature of 160–170°C and a pressure of 10–15 MPa to obtain a high-strength, high-weather-resistant polyvinyl chloride composite material.

[0014] Beneficial technical effects:

[0015] This application obtains grafted polyvinyl chloride by reacting 4-aminobenzoic acid ester compounds with polyvinyl chloride, and then fully mixes the grafted polyvinyl chloride with inorganic fillers, plasticizers, stabilizers, lubricants and antioxidants under certain formulation and process to obtain a high-strength and high-weather-resistant polyvinyl chloride composite material.

[0016] The applicant discovered that during the preparation of graft-modified polyvinyl chloride (PVC), the chlorine atoms on the PVC molecular chain are replaced by amino groups from 4-aminobenzoic acid ester compounds, forming a graft copolymer bonded by chemical bonds. The grafted amino and ester groups can form hydrogen bonds, enhancing the interaction between the grafted PVC molecular chains and improving the strength of the PVC composite material. Simultaneously, the flexible segments of the ester groups can increase the mobility of local chain segments, and combined with the polarity of the amino groups, can improve the interfacial compatibility between the grafted PVC molecular chains and inorganic fillers and other components, thereby further improving the strength of the PVC composite material. Furthermore, the benzene ring in the 4-aminobenzoic acid ester compounds forms a larger conjugated system with the amino and ester groups through conjugation. This larger conjugated system enhances the UV absorption efficiency of the grafted PVC. Moreover, the conjugated system in the aforementioned PVC composite material is generated through chemical bonding and is not easily migrated or altered, resulting in a PVC composite material with excellent weather resistance. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the chemical reaction for preparing graft-modified polyvinyl chloride.

[0018] Figure 2 This is a schematic diagram of the process for preparing high-strength, high-weather-resistant polyvinyl chloride composite materials. Detailed Implementation

[0019] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the application will be further described in detail below with reference to embodiments. However, this should not be construed as limiting the scope of this application to the following examples. All other embodiments obtained by those skilled in the art without creative effort without departing from the above-described methodological spirit of this application are within the scope of protection of this application.

[0020] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0021] The singular forms “for,” “a,” “any one,” and “as described” used in this application are intended to include the plural forms unless the context clearly indicates otherwise.

[0022] Furthermore, the terms "first" and "second" appearing in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In a first aspect, this application provides a high-strength, high-weather-resistant polyvinyl chloride composite material, comprising graft-modified polyvinyl chloride; the graft-modified polyvinyl chloride is obtained by reacting a 4-aminobenzoic acid ester compound with polyvinyl chloride, the reaction process being as follows: Figure 1 As shown; the 4-aminobenzoic acid ester compounds include any one of n-propyl 4-aminobenzoate, isopropyl 4-aminobenzoate, n-butyl 4-aminobenzoate, isobutyl 4-aminobenzoate, and 2-ethylhexyl 4-aminobenzoate.

[0024] In one feasible implementation, the structure of the grafted modified polyvinyl chloride includes:

[0025]

[0026] R includes any one of propyl, isopropyl, butyl, isobutyl and 2-ethylhexyl.

[0027] In one feasible implementation, the high-strength, high-weather-resistant polyvinyl chloride composite material further includes inorganic fillers, plasticizers, stabilizers, lubricants, and antioxidants.

[0028] In one feasible implementation, the mass ratio of the grafted modified polyvinyl chloride, inorganic filler, plasticizer, stabilizer, lubricant and antioxidant in the high-strength and high-weather-resistant polyvinyl chloride composite material is (50-60): (10-15): (20-30): (2-5): (1-3): (0.5-1).

[0029] In one feasible implementation, the inorganic filler material includes at least one of light calcium carbonate, talc, wollastonite, kaolin, and mica powder.

[0030] In one feasible implementation, the plasticizer includes at least one of acetylated tributyl citrate, epoxidized soybean oil, diisononyl adipate, and dioctyl terephthalate.

[0031] In one feasible implementation, the stabilizer comprises at least one of calcium lauryl oleate / zinc ricinoleate complex, calcium stearate / zinc stearate complex, lanthanum stearate, tributyltin oxide, and pentaerythritol diphosphite.

[0032] In one feasible implementation, the lubricant comprises at least one of oxidized polyethylene wax, ethylene bis-stearamide, and silicone masterbatch.

[0033] In one feasible implementation, the antioxidant includes at least one of di(2,2,6,6-tetramethylpiperidine) sebacate, 2,6-di-tert-butyl-p-cresol, and dilauryl thiodipropionate.

[0034] Secondly, this application provides a method for preparing a high-strength, high-weather-resistant polyvinyl chloride composite material, such as... Figure 2 As shown, it includes the following steps:

[0035] Polyvinyl chloride (PVC) was added to DMF, and under nitrogen protection, the temperature was raised to 70–90°C. Then, 4-aminobenzoic acid esters and Lewis acid were added, and the mixture was stirred and reacted for 4–6 hours. The product was precipitated, washed, and dried to obtain grafted PVC.

[0036] Weigh the grafted modified polyvinyl chloride, inorganic filler, plasticizer, stabilizer, lubricant and antioxidant according to the proportion, add them to a high-speed mixer, mix at 80-100℃ for 10-20 minutes, cool and discharge to obtain the premix;

[0037] Add the premix to an internal mixer and mix at 160–180°C and 30–50 rpm for 5–15 minutes to obtain the mixture.

[0038] The compound is calendered using a four-roll calender at a roll temperature of 160–170°C and a pressure of 10–15 MPa to obtain a high-strength, high-weather-resistant polyvinyl chloride composite material.

[0039] In one feasible implementation, the mass ratio of the polyvinyl chloride, the 4-aminobenzoic acid compound, and the Lewis acid is (82-94):(5-16):(0.5-2).

[0040] In one feasible implementation, the Lewis acid includes at least one of zinc chloride and aluminum chloride.

[0041] In one feasible implementation, the mass of the DMF is 5 to 10 times that of the polyvinyl chloride.

[0042] The following will describe in detail, with reference to different embodiments, a high-strength and high-weather-resistant polyvinyl chloride composite material and its preparation method provided in this application.

[0043] Example 1:

[0044] like Figure 2 As shown, a method for preparing a high-strength, high-weather-resistant polyvinyl chloride composite material includes the following steps:

[0045] 1. Polyvinyl chloride was added to DMF, along with 4-aminobenzoic acid n-propyl ester and zinc chloride. The mixture was heated to 80°C under nitrogen protection and stirred for 5 hours. The product was then precipitated, washed, and dried to obtain grafted modified polyvinyl chloride.

[0046] In the above steps, the mass ratio of polyvinyl chloride, 4-aminobenzoic acid n-propyl ester, and zinc chloride is 88:10:2; the mass of DMF is 6 times that of polyvinyl chloride.

[0047] 2. Weigh the grafted modified polyvinyl chloride, light calcium carbonate, tributyl acetyl citrate, calcium laurate / zinc ricinoleate complex, oxidized polyethylene wax, and di(2,2,6,6-tetramethylpiperidine) sebacate, add them to a high-speed mixer, mix at 90°C for 15 minutes, cool and discharge to obtain the premix.

[0048] In the above steps, the mass ratio of grafted modified polyvinyl chloride, light calcium carbonate, tributyl acetylacetate, calcium laurate / zinc ricinoleate complex, oxidized polyethylene wax, and di(2,2,6,6-tetramethylpiperidine) sebacate is 55:12:27.5:3:2:0.5.

[0049] 3. Add the premix to the internal mixer and mix at 170°C and 40 rpm for 10 minutes to obtain the mixture;

[0050] 4. The compound is calendered by a four-roll calender at a roll temperature of 165℃ and a pressure of 12MPa to obtain a high-strength and high-weather-resistant polyvinyl chloride composite material.

[0051] Example 2:

[0052] like Figure 2 As shown, a method for preparing a high-strength, high-weather-resistant polyvinyl chloride composite material includes the following steps:

[0053] 1. Polyvinyl chloride was added to DMF, along with isobutyl 4-aminobenzoate and aluminum chloride. The mixture was heated to 90°C under nitrogen protection and stirred for 4 hours. The product was then precipitated, washed, and dried to obtain grafted modified polyvinyl chloride.

[0054] In the above steps, the mass ratio of polyvinyl chloride, isobutyl 4-aminobenzoate, and aluminum chloride is 82:16:2; the mass of DMF is 5 times that of polyvinyl chloride.

[0055] 2. Weigh the grafted modified polyvinyl chloride, talc, epoxidized soybean oil, calcium stearate / zinc stearate complex, ethylene bis-stearamide, and 2,6-di-tert-butyl-p-cresol, add them to a high-speed mixer, mix at 100°C for 10 minutes, cool and discharge to obtain the premix.

[0056] In the above steps, the mass ratio of grafted modified polyvinyl chloride, talc, epoxidized soybean oil, calcium stearate / zinc stearate complex, ethylene bis-stearamide, and 2,6-di-tert-butyl-p-cresol is 50:15:28:4:2:1.

[0057] 3. Add the premix to the internal mixer and mix at 180°C and 50 rpm for 5 minutes to obtain the mixture;

[0058] 4. The compound is calendered by a four-roll calender at a roll temperature of 160℃ and a pressure of 15MPa to obtain a high-strength and high-weather-resistant polyvinyl chloride composite material.

[0059] Example 3:

[0060] like Figure 2 As shown, a method for preparing a high-strength, high-weather-resistant polyvinyl chloride composite material includes the following steps:

[0061] 1. Polyvinyl chloride was added to DMF, along with 2-ethylhexyl-4-aminobenzoate and zinc chloride. The mixture was heated to 70°C under nitrogen protection and stirred for 6 hours. The product was then precipitated, washed, and dried to obtain grafted modified polyvinyl chloride.

[0062] In the above steps, the mass ratio of polyvinyl chloride, 2-ethylhexyl-4-aminobenzoate, and zinc chloride is 94:5:1; the mass of DMF is 10 times that of polyvinyl chloride.

[0063] 2. Weigh the grafted modified polyvinyl chloride, wollastonite, diisononyl adipate, lanthanum stearate, silicone masterbatch, and dilauryl thiodipropionate, add them to a high-speed mixer, mix at 80°C for 20 minutes, cool and discharge to obtain the premix.

[0064] In the above steps, the mass ratio of grafted modified polyvinyl chloride, wollastonite, diisononyl adipate, lanthanum stearate, silicone masterbatch, and dilauryl thiodipropionate is 60:12.5:22:2:3:0.5.

[0065] 3. Add the premix to the internal mixer and mix at 160℃ and 30 rpm for 15 minutes to obtain the mixture;

[0066] 4. The compound is calendered by a four-roll calender at a roll temperature of 170℃ and a pressure of 10MPa to obtain a high-strength and high-weather-resistant polyvinyl chloride composite material.

[0067] Example 4:

[0068] like Figure 2 As shown, a method for preparing a high-strength, high-weather-resistant polyvinyl chloride composite material includes the following steps:

[0069] 1. Polyvinyl chloride was added to DMF, along with 4-aminobenzoic acid n-butyl ester and aluminum chloride. The mixture was heated to 85°C under nitrogen protection and stirred for 5.5 hours. The product was then precipitated, washed, and dried to obtain grafted modified polyvinyl chloride.

[0070] In the above steps, the mass ratio of polyvinyl chloride, 4-aminobenzoate n-butyl ester, and aluminum chloride is 87:12:1; the mass of DMF is 9 times that of polyvinyl chloride.

[0071] 2. Weigh the grafted modified polyvinyl chloride, kaolin, dioctyl terephthalate, tributyltin oxide, oxidized polyethylene wax, and di(2,2,6,6-tetramethylpiperidine) sebacate, add them to a high-speed mixer, mix at 95°C for 12 minutes, cool and discharge to obtain the premix.

[0072] In the above steps, the mass ratio of grafted modified polyvinyl chloride, kaolin, dioctyl terephthalate, tributyltin oxide, oxidized polyethylene wax, and di(2,2,6,6-tetramethylpiperidine) sebacate is 57:12:23:5:2.5:0.5.

[0073] 3. Add the premix to the internal mixer and mix at 175°C and 45 rpm for 8 minutes to obtain the mixture;

[0074] 4. The compound is calendered by a four-roll calender at a roll temperature of 165℃ and a pressure of 13MPa to obtain a high-strength and high-weather-resistant polyvinyl chloride composite material.

[0075] Example 5:

[0076] like Figure 2 As shown, a method for preparing a high-strength, high-weather-resistant polyvinyl chloride composite material includes the following steps:

[0077] 1. Polyvinyl chloride was added to DMF, along with isopropyl 4-aminobenzoate and zinc chloride. The mixture was heated to 75°C under nitrogen protection and stirred for 6 hours. The product was then precipitated, washed, and dried to obtain grafted modified polyvinyl chloride.

[0078] In the above steps, the mass ratio of polyvinyl chloride, isopropyl 4-aminobenzoate, and zinc chloride is 91:8.5:0.5; the mass of DMF is 7 times that of polyvinyl chloride.

[0079] 2. Weigh the grafted modified polyvinyl chloride, mica powder, epoxidized soybean oil, pentaerythritol diphosphite, ethylene bis-stearamide, and dilauryl thiodipropionate, add them to a high-speed mixer, mix at 85°C for 18 minutes, cool and discharge to obtain the premix.

[0080] In the above steps, the mass ratio of grafted modified polyvinyl chloride, mica powder, epoxidized soybean oil, pentaerythritol diphosphite, ethylene bis-stearamide, and dilauryl thiodipropionate is 54:14:26:3.5:1.8:0.7.

[0081] 3. Add the premix to the internal mixer and mix at 170℃ and 35 rpm for 12 minutes to obtain the mixture;

[0082] 4. The compound is calendered by a four-roll calender at a roll temperature of 162℃ and a pressure of 14MPa to obtain a high-strength and high-weather-resistant polyvinyl chloride composite material.

[0083] Example 6:

[0084] like Figure 2 As shown, a method for preparing a high-strength, high-weather-resistant polyvinyl chloride composite material includes the following steps:

[0085] 1. Polyvinyl chloride was added to DMF, along with 4-aminobenzoic acid n-propyl ester and aluminum chloride. The mixture was heated to 88°C under nitrogen protection and stirred for 4.5 hours. The product was then precipitated, washed, and dried to obtain grafted modified polyvinyl chloride.

[0086] In the above steps, the mass ratio of polyvinyl chloride, 4-aminobenzoic acid n-propyl ester, and aluminum chloride is 83:15:2; the mass of DMF is 8 times that of polyvinyl chloride.

[0087] 2. Weigh the grafted modified polyvinyl chloride, talc, tributyl acetylacetate, calcium stearate / zinc stearate complex, silicone masterbatch, and 2,6-di-tert-butyl-p-cresol, add them to a high-speed mixer, mix at 100°C for 10 minutes, cool and discharge to obtain the premix.

[0088] In the above steps, the mass ratio of grafted modified polyvinyl chloride, talc, tributyl acetylacetic acid, calcium stearate / zinc stearate complex, silicone masterbatch, and 2,6-di-tert-butyl-p-cresol is 58:11.5:23:4.5:2.2:0.8.

[0089] 3. Add the premix to the internal mixer and mix at 165℃ and 48 rpm for 9 minutes to obtain the mixture;

[0090] 4. The compound is calendered by a four-roll calender at a roll temperature of 168℃ and a pressure of 11MPa to obtain a high-strength and high-weather-resistant polyvinyl chloride composite material.

[0091] Comparative Example 1:

[0092] A method for preparing a high-strength, high-weather-resistant polyvinyl chloride composite material includes the following steps:

[0093] 1. Weigh out polyvinyl chloride, light calcium carbonate, tributyl acetyl citrate, calcium laurate / zinc ricinoleate complex, oxidized polyethylene wax, and di(2,2,6,6-tetramethylpiperidine) sebacate, add them to a high-speed mixer, mix at 90°C for 15 minutes, cool and discharge to obtain a premix.

[0094] In the above steps, the mass ratio of polyvinyl chloride, light calcium carbonate, tributyl acetylacetate, calcium laurate / zinc ricinoleate complex, oxidized polyethylene wax, and di(2,2,6,6-tetramethylpiperidine) sebacate is 55:12:27.5:3:2:0.5.

[0095] 2. Add the premixed material to the internal mixer and mix at 170℃ and 40 rpm for 10 minutes to obtain the mixture.

[0096] 3. The compound is calendered by a four-roll calender at a roll temperature of 165℃ and a pressure of 12MPa to obtain a high-strength and high-weather-resistant polyvinyl chloride composite material.

[0097] Comparative Example 2:

[0098] A method for preparing a high-strength, high-weather-resistant polyvinyl chloride composite material includes the following steps:

[0099] 1. Polyvinyl chloride was added to DMF, along with 2-ethylhexylbenzoate and zinc chloride. The mixture was heated to 70°C under nitrogen protection and stirred for 6 hours. The product was then precipitated, washed, and dried to obtain modified polyvinyl chloride.

[0100] In the above steps, the mass ratio of polyvinyl chloride, 2-ethylhexylbenzoate, and zinc chloride is 94:5:1; the mass of DMF is 10 times that of polyvinyl chloride.

[0101] 2. Weigh the grafted modified polyvinyl chloride, wollastonite, diisononyl adipate, lanthanum stearate, silicone masterbatch, and dilauryl thiodipropionate, add them to a high-speed mixer, mix at 80°C for 20 minutes, cool and discharge to obtain the premix.

[0102] In the above steps, the mass ratio of grafted modified polyvinyl chloride, wollastonite, diisononyl adipate, lanthanum stearate, silicone masterbatch, and dilauryl thiodipropionate is 60:12.5:22:2:3:0.5.

[0103] 3. Add the premix to the internal mixer and mix at 160℃ and 30 rpm for 15 minutes to obtain the mixture;

[0104] 4. The compound is calendered by a four-roll calender at a roll temperature of 170℃ and a pressure of 10MPa to obtain a high-strength and high-weather-resistant polyvinyl chloride composite material.

[0105] Comparative Example 3:

[0106] A method for preparing a high-strength, high-weather-resistant polyvinyl chloride composite material includes the following steps:

[0107] 1. Polyvinyl chloride was added to DMF, along with 4-n-propylaniline and aluminum chloride. The mixture was heated to 88°C under nitrogen protection and stirred for 4.5 hours. The product was then precipitated, washed, and dried to obtain grafted modified polyvinyl chloride.

[0108] In the above steps, the mass ratio of polyvinyl chloride, 4-n-propylaniline, and aluminum chloride is 83:15:2; the mass of DMF is 8 times that of polyvinyl chloride.

[0109] 2. Weigh the grafted modified polyvinyl chloride, talc, tributyl acetylacetate, calcium stearate / zinc stearate complex, silicone masterbatch, and 2,6-di-tert-butyl-p-cresol, add them to a high-speed mixer, mix at 100°C for 10 minutes, cool and discharge to obtain the premix.

[0110] In the above steps, the mass ratio of grafted modified polyvinyl chloride, talc, tributyl acetylacetic acid, calcium stearate / zinc stearate complex, silicone masterbatch, and 2,6-di-tert-butyl-p-cresol is 58:11.5:23:4.5:2.2:0.8.

[0111] 3. Add the premix to the internal mixer and mix at 165℃ and 48 rpm for 9 minutes to obtain the mixture;

[0112] 4. The compound is calendered by a four-roll calender at a roll temperature of 168℃ and a pressure of 11MPa to obtain a high-strength and high-weather-resistant polyvinyl chloride composite material.

[0113] The tensile strength of the polyvinyl chloride composite material prepared in this application was tested with reference to GB / T 1040.1-2018; the flexural strength of the prepared polyvinyl chloride composite material was tested with reference to GB / T 9341-2008; the test results of both demonstrate the high strength of the polyvinyl chloride composite material prepared in this application.

[0114] Referring to GB / T16422.3-2022, the polyvinyl chloride composite material prepared in this application was aged under a fluorescent ultraviolet lamp. Furthermore, referring to GB / T 1040.1-2018 and GB / T 9341-2008, the tensile strength and flexural strength of the aged polyvinyl chloride composite material were tested, and the retention rates of both were calculated; thereby demonstrating the weather resistance of the polyvinyl chloride composite material prepared in this application.

[0115] Table 1. Test results of polyvinyl chloride composite materials prepared in the examples and comparative examples.

[0116]

[0117]

[0118] As shown in Table 1, the tensile strength, flexural strength, tensile strength retention rate, and flexural strength retention rate of Examples 1-6 are all better than those of Comparative Examples 1-2.

[0119] This is because, during the preparation of graft-modified polyvinyl chloride (PVC), the chlorine atoms on the PVC molecular chain are replaced by amino groups from 4-aminobenzoic acid esters, forming a graft copolymer bonded by chemical bonds. The grafted amino and ester groups can form hydrogen bonds, enhancing the interaction between the grafted PVC molecular chains and improving the strength of the PVC composite material. Simultaneously, the flexible segments of the ester groups increase the mobility of local segments, and combined with the polarity of the amino groups, improve the interfacial compatibility between the grafted PVC molecular chains and inorganic fillers and other components, further enhancing the strength of the PVC composite material. Furthermore, the benzene ring in the 4-aminobenzoic acid esters forms a larger conjugated system with the amino and ester groups through conjugation. This larger conjugated system enhances the UV absorption efficiency of the grafted PVC. Moreover, since the conjugated system in the aforementioned PVC composite material is generated through chemical bonding, it is not easily migrated or altered, resulting in a PVC composite material with excellent weather resistance.

[0120] In Comparative Example 1, no graft-modified PVC was prepared, thus preventing the formation of hydrogen bonds between PVC molecular chains and the conjugated system that enhances UV absorption efficiency. Consequently, the resulting PVC composite material exhibited the worst strength and weather resistance. In Comparative Example 2, 2-ethylhexylbenzoate was used instead of 4-aminobenzoate compounds in the preparation of the modified PVC, preventing the formation of chemically bonded graft-modified PVC. The resulting PVC composite material also showed poor strength and weather resistance. In Comparative Example 3, although graft-modified PVC could be prepared via reaction using 4-n-propylaniline, the inability to form a conjugated system resulted in a PVC composite material with better strength and weather resistance than Comparative Examples 1 and 2, but still inferior to Examples 1-6.

[0121] The above results demonstrate and describe the basic principles and main features of this application, as well as its advantages.

[0122] Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of this application as claimed. The scope of protection of this application is defined by the equivalents of the appended claims.

Claims

1. A high-strength, high-weather-resistant polyvinyl chloride composite material, characterized in that, The product comprises graft-modified polyvinyl chloride (PVC), inorganic filler, plasticizer, stabilizer, lubricant, and antioxidant; the mass ratio of the graft-modified PVC, inorganic filler, plasticizer, stabilizer, lubricant, and antioxidant is (50~60):(10~15):(20~30):(2~5):(1~3):(0.5~1); the graft-modified PVC is obtained by reacting 4-aminobenzoic acid esters with PVC; the 4-aminobenzoic acid esters include any one of n-propyl 4-aminobenzoate, isopropyl 4-aminobenzoate, n-butyl 4-aminobenzoate, isobutyl 4-aminobenzoate, and 2-ethylhexyl 4-aminobenzoate; the preparation method of the graft-modified PVC is as follows: Polyvinyl chloride (PVC) was added to DMF, and under nitrogen protection, the temperature was raised to 70-90°C. Then, 4-aminobenzoic acid compounds and Lewis acid were added, and the mixture was stirred and reacted for 4-6 hours. The product was precipitated, washed, and dried to obtain grafted PVC. The mass ratio of the polyvinyl chloride, 4-aminobenzoic acid compound, and Lewis acid is (82~94):(5~16):(0.5~2); the Lewis acid includes at least one of zinc chloride and aluminum chloride; the mass of the DMF is 5~10 times that of the polyvinyl chloride.

2. The high-strength, high-weather-resistant polyvinyl chloride composite material according to claim 1, characterized in that, The structure of the grafted polyvinyl chloride includes: ； R includes any one of propyl, isopropyl, butyl, isobutyl and 2-ethylhexyl.

3. The high-strength, high-weather-resistant polyvinyl chloride composite material according to claim 1, characterized in that, The inorganic filler material includes at least one of light calcium carbonate, talc, wollastonite, kaolin, and mica powder.

4. The high-strength, high-weather-resistant polyvinyl chloride composite material according to claim 1, characterized in that, The plasticizer includes at least one of acetylated tributyl citrate, epoxidized soybean oil, diisononyl adipate, and dioctyl terephthalate.

5. The high-strength, high-weather-resistant polyvinyl chloride composite material according to claim 1, characterized in that, The stabilizer includes at least one of calcium lauryl oleate / zinc castor oil complex, calcium stearate / zinc stearate complex, lanthanum stearate, tributyltin oxide, and pentaerythritol diphosphite.

6. The high-strength, high-weather-resistant polyvinyl chloride composite material according to claim 1, characterized in that, The lubricant includes at least one of oxidized polyethylene wax, ethylene bis-stearamide, and silicone masterbatch.

7. The high-strength, high-weather-resistant polyvinyl chloride composite material according to claim 1, characterized in that, The antioxidant includes at least one of di(2,2,6,6-tetramethylpiperidine) sebacate, 2,6-di-tert-butyl-p-cresol, and dilauryl thiodipropionate.

8. The high-strength, high-weather-resistant polyvinyl chloride composite material according to claim 1, characterized in that, Its preparation method includes the following steps: Weigh the grafted modified polyvinyl chloride, inorganic filler, plasticizer, stabilizer, lubricant and antioxidant, add them to a high-speed mixer, mix at 80~100℃ for 10~20min, cool and discharge to obtain the premix; Add the premix to an internal mixer and mix at 160~180℃ and 30~50rpm for 5~15min to obtain the mixture. The compound is calendered by a four-roll calender at a roll temperature of 160~170℃ and a pressure of 10~15MPa to obtain a high-strength and high-weather-resistant polyvinyl chloride composite material.

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