Vegetable oil-based PVC plasticizer as well as preparation method and application thereof

Abstract

The invention discloses a vegetable oil-based PVC (polyvinyl chloride) plasticizer, the structural formula of which is as shown in formula (I), formula (II) or formula (III), the vegetable oil-based PVC plasticizer adopts an aromatic ring and long-chain fatty acid ester to construct a core-shell structure, the rigidity of the aromatic ring is utilized to endow the vegetable oil-based PVC plasticizer as the PVC plasticizer to improve the mechanical strength of a PVC material, and meanwhile, the toughness of the PVC material is improved through the flexible part of the long-chain fatty acid ester; the plant oil-based plasticizer has plasticizing performance, heat-resistant stability and low migration rate. The invention also discloses a preparation method and application of the plant oil-based PVC plasticizer. # imgabs 0 # formula (I) # imgabs 1 # formula (II) # imgabs 2 # formula (III).

Description

Technical Field

[0001] The present invention belongs to the technical field of plastic additives, and particularly relates to a vegetable oil-based PVC plasticizer and its preparation method and application. Background Art

[0002] In recent years, with the increasingly strict environmental protection regulations and the promotion of the sustainable development strategy, the use of traditional petroleum-based plasticizers has been gradually replaced and restricted due to their potential ecological toxicity and bioaccumulation. Polyvinyl chloride (PVC), as one of the most widely produced general plastics globally, highly depends on plasticizers during the processing to improve the flexibility and processing performance of PVC products. However, existing commercial plasticizers still have obvious deficiencies in terms of environmental friendliness, durability, and plasticizing efficiency, and there is an urgent need to develop new green alternatives.

[0003] Vegetable oil-based plasticizers have become a current research hotspot due to their characteristics such as renewable raw materials, biodegradability, and low toxicity. Natural oils such as soybean oil, castor oil, and palm oil can be derivatized into a series of compounds with plasticizing functions through chemical modifications such as epoxidation, esterification, or polymerization. For example, epoxidized vegetable oils such as epoxidized soybean oil have been partially commercialized, but their compatibility with PVC is poor, they are prone to migration and precipitation, and their improvement of the low-temperature toughness and thermal stability of PVC is limited. In addition, existing vegetable oil-based plasticizers generally have problems of low molecular weight and insufficient polarity, resulting in a decrease in the mechanical strength of the plasticized PVC products, especially in long-term use, the performance is prone to attenuation.

[0004] In the prior art, the performance of vegetable oil-based plasticizers is mainly improved by the following methods: (1) increasing the molecular weight through polyol esterification or polymerization reactions to reduce migration; (2) introducing polar groups such as epoxy groups and hydroxyl groups to enhance the interaction with PVC; (3) designing molecules with a rigid-flexible synergistic structure to balance the plasticizing effect and mechanical properties. However, these methods face bottlenecks such as complex synthesis processes, high costs, or single modification effects, and vegetable oil-based plasticizers cannot simultaneously have plasticizing performance, heat stability, and low migration rate. Against this background, it is of great significance to develop vegetable oil-based plasticizers with the above effects. Summary of the Invention

[0005] The purpose of the present invention is to provide a vegetable oil-based PVC plasticizer and its preparation method and application to solve the technical problem that existing vegetable oil-based plasticizers cannot simultaneously have plasticizing performance, heat stability, and low migration rate.

[0006] According to the first aspect of the present invention, there is provided a vegetable oil-based PVC plasticizer, and the structural formula of the vegetable oil-based PVC plasticizer is shown as formula (I), formula (II), or formula (III):

[0007] Formula (I)

[0008] Formula (II)

[0009] Formula (III); Among them, the structure of Ar in Formula (I), Formula (II) or Formula (III) is , , or .

[0010] The vegetable oil-based PVC plasticizer of the present invention constructs a core-shell structure with an aromatic ring and a long-chain fatty acid ester. The rigidity of the aromatic ring endows it with the ability to improve the mechanical properties of PVC materials as a PVC plasticizer, while the flexible part of the long-chain fatty acid ester endows the material with good toughness. Moreover, the structure of the vegetable oil-based PVC plasticizer of the present invention has polar functional groups, which can enhance the hydrogen bond interaction with the PVC chain and thus inhibit the migration of the plasticizer. Experiments show that the vegetable oil-based PVC plasticizer has both plasticizing performance, heat stability and low migration rate, shows excellent compatibility in PVC materials, and can significantly improve the rigidity, elongation at break and high-temperature stability of PVC materials.

[0011] According to the second aspect of the present invention, there is provided a method for preparing a vegetable oil-based PVC plasticizer, comprising the following steps: (1) Saponify vegetable oil with a 95% ethanol solution containing sodium hydroxide to obtain a mixed solution. After removing the unsaponified matter in the mixed solution, adjust the pH value to 3-4 with phosphoric acid, then separate and purify the mixed solution, dry the purified product and remove the solvent to obtain vegetable oil fatty acid; (2) Dissolve vegetable oil fatty acid, a compound having an aromatic ring and a phenolic hydroxyl group, and N,N,N',N'-tetramethylchloroformamidinium hexafluorophosphate (TCFH) in a first organic solvent, and then dropwise add a basic catalyst to react. Separate and purify the reaction product to obtain a first reaction product; (3) Dissolve the first reaction product in a second organic solvent, and then sequentially add an epoxidizing agent and a sodium carbonate solution to form a two-phase system; the first reaction product and the epoxidizing agent carry out an epoxidation reaction in the two-phase system. After the reaction is completed, separate the organic phase, and separate and purify the reaction product in the organic phase to obtain it; Among them, the compound having an aromatic ring and a phenolic hydroxyl group is phloroglucinol, 2,4,6-tris(4-hydroxyphenyl)-1,3,5-triyltri-phenol, 2,4,6-tris(4-hydroxyphenyl)-s-triazine or 4,4',4''-tricyclo[3.3.1.1 3.7 decane-1,3,5-triyltri-phenol; the vegetable oil is soybean oil, linseed oil or palm oil.

[0012] The preparation method of the plant oil-based PVC plasticizer in the present invention first uses inexpensive plant oil as the raw material. Utilizing the property that triglycerides in plant oil are easily broken, plant oil fatty acid is obtained through the saponification reaction of plant oil and sodium hydroxide, solving the technical problem of high cost in the process of improving the performance of plant oil-based plasticizers in existing methods. Then, the plant oil fatty acid and the compound with an aromatic ring and a phenolic hydroxyl group are introduced with a rigid aromatic ring core through an esterification reaction to replace the original glycerol skeleton of the plant oil, and the existing flexible fatty acid long chain is retained. A plant oil derivative with a rigid-flexible structure (the first reaction product) is directly synthesized in-situ, and polar functional groups (epoxy groups, ester groups) are further introduced through an epoxidation reaction to increase the polarity of the plant oil-based PVC plasticizer. Finally, a plasticizer molecule with a core-shell structure is constructed. The preparation method is simple and can enhance the hydrogen bond interaction between the plant oil-based PVC plasticizer and the PVC chain.

[0013] In some embodiments, in step (1), the temperature of the saponification reaction is 65 - 75 °C.

[0014] In some embodiments, in step (2), the temperature of the reaction with the addition of the basic catalyst is room temperature.

[0015] In some embodiments, in step (3), the temperature of the epoxidation reaction is room temperature.

[0016] In some embodiments, in step (1), the molar ratio of plant oil to sodium hydroxide is (0.07 - 0.1):1.

[0017] In some embodiments, in step (2), the molar ratio of the compound with an aromatic ring and a phenolic hydroxyl group, plant oil fatty acid, N,N,N',N'-tetramethylchloroformamidinium hexafluorophosphate, and the basic catalyst is 1:(4.0 - 6.0):(10.0 - 15.0):(9.0 - 12.0). Preferably, the molar ratio of the compound with an aromatic ring and a phenolic hydroxyl group, plant oil fatty acid, N,N,N',N'-tetramethylchloroformamidinium hexafluorophosphate, and the basic catalyst is 1:5.0:10.0:10.0.

[0018] In some embodiments, the basic catalyst is selected from at least one of pyridine and N-methylimidazole.

[0019] In some embodiments, the first organic solvent is acetonitrile, and the second organic solvent is selected from at least one of dichloromethane and chloroform.

[0020] In some embodiments, the epoxidizing agent is meta-chloroperoxybenzoic acid (m-CPBA).

[0021] In some embodiments, the molar ratio of the epoxidizing agent to the vegetable oil fatty acid is (3.5 - 5.5):1. Preferably, the molar ratio of the epoxidizing agent to the vegetable oil fatty acid is 4.0:1.

[0022] In some embodiments, the method for preparing the vegetable oil-based PVC plasticizer comprises the following steps: (1) Saponify the vegetable oil with a 95% ethanol solution containing sodium hydroxide to obtain a mixture, then dilute the mixture with distilled water, extract the unsaponified matter in the mixture with ethyl acetate, adjust the pH value to 3 - 4 with phosphoric acid, then filter and wash the filtrate with water until neutral. The product is dried with anhydrous sodium sulfate, and finally the solvent is removed by rotary evaporation to obtain the vegetable oil fatty acid; (2) Dissolve the vegetable oil fatty acid, the compound having an aromatic ring and a phenolic hydroxyl group, and N,N,N',N'-tetramethylchloroformamidinium hexafluorophosphate in a first organic solvent, and add a basic catalyst dropwise to the first organic solvent to obtain a reaction mixture; the reaction mixture is stirred overnight, then the reaction mixture is diluted with ethyl acetate and the diluted reaction mixture is poured into a saturated sodium bicarbonate solution, and the organic layer is collected by liquid separation, then dried with anhydrous sodium sulfate and concentrated under reduced pressure to obtain a crude product, and the crude product is subjected to silica gel column chromatography to obtain a first reaction product; (3) Dissolve the first reaction product in dichloromethane, first add an epoxidizing agent to the dichloromethane, and then add a sodium carbonate solution to the dichloromethane to form a two-phase system; the two-phase system is stirred overnight to carry out an epoxidation reaction of the first reaction product and the epoxidizing agent in the two-phase system, and a second organic phase is separated; then it is washed successively with saturated sodium thiosulfate and sodium bicarbonate solutions, dried with anhydrous magnesium sulfate, and then filtered through a short column of basic alumina to obtain the product.

[0023] In some embodiments, the eluent used in the silica gel column chromatography is composed of n-hexane and ethyl acetate, and the volume ratio of n-hexane to ethyl acetate is 100:2.

[0024] According to the third aspect of the present invention, there is provided the application of the vegetable oil-based PVC plasticizer. Specifically, the application is the application of the vegetable oil-based PVC plasticizer in the preparation of PVC materials.

[0025] After the vegetable oil-based PVC plasticizer of the present invention is blended with PVC, the plasticizing performance, mechanical strength and heat resistance stability of the PVC material are significantly improved. The results of in vitro cytotoxicity experiments show that the plasticizer is non-toxic to L929 cells.

[0026] In some embodiments, the PVC material is a food packaging material, a medical and health product or a children's toy.

[0027] In some embodiments, when the PVC material is a PVC film, the PVC film is prepared through the following steps: Dissolve PVC in an organic solvent, add a vegetable oil-based PVC plasticizer, stir, and then dry to remove the organic solvent, thus obtaining the PVC film. Specifically, the organic solvent is tetrahydrofuran (THF).

[0028] In some embodiments, the dosage of the vegetable oil-based PVC plasticizer is 20% - 35% of the mass of the PVC film. Preferably, the dosage of the vegetable oil-based PVC plasticizer is 30% of the mass of the PVC film.

[0029] In some embodiments, the mass concentration of PVC in tetrahydrofuran is 4.5 - 5.5 g / mL. Preferably, the mass concentration of PVC in tetrahydrofuran is 5.0 g / mL.

[0030] The beneficial effects of the present invention are as follows: (1) The vegetable oil-based PVC plasticizer of the present invention has a "rigid core - flexible arm" molecular structure. The aromatic ring rigid structure and the long chain of fatty acid esters can solve the defect that the mechanical strength improvement of traditional vegetable oil-based plasticizers used in PVC products is insufficient; moreover, it has polar functional groups, which can enhance the hydrogen bond interaction with the PVC chain, and has good compatibility with PVC, which can inhibit the migration of the plasticizer; (2) The vegetable oil-based PVC plasticizer of the present invention introduces a rigid aromatic ring core into the vegetable oil through a one-step catalytic esterification process to replace the glycerol skeleton of the vegetable oil, and retains the flexible fatty acid long chain of the vegetable oil, directly in-situ synthesizing a vegetable oil derivative with a rigid - flexible structure. The preparation method is simple; (3) The vegetable oil-based PVC plasticizer provided by the present invention is non-toxic, environmentally friendly, has good high-temperature resistance, and has excellent plasticizing performance for PVC materials, and has a very broad application prospect in the preparation of PVC materials. Description of the Drawings

[0031] Figure 1 It is the synthesis route diagram of the vegetable oil-based PVC plasticizer of the present invention; Figure 2 It is the 1H NMR spectrum diagram of SFA in Example 1 of the present invention; Figure 3 It is the 1H NMR spectrum diagram of SFAP in Example 1 of the present invention; Figure 4 It is the 1H NMR spectrum diagram of EPO - SFAP in Example 1 of the present invention; Figure 5 It is the 1H NMR spectrum diagram of SFATB in Example 2 of the present invention; Figure 6 It is the 1H NMR spectrum diagram of EPO - SFATB in Example 2 of the present invention; Figure 71H NMR spectrum of SFATT in Example 3 of the present invention; Figure 8 1H NMR spectrum of EPO - SFATT in Example 3 of the present invention; Figure 9 1H NMR spectrum of SFATA in Example 4 of the present invention; Figure 10 1H NMR spectrum of EPO - SFATA in Example 4 of the present invention; Figure 11 Stress - strain curves of PVC films prepared in Application Example 1, Application Example 2 and Comparative Example 1 of the present invention; Figure 12 Test results of glass transition temperature of PVC films prepared in Application Example 1, Application Example 2 and Comparative Example 1 of the present invention; Figure 13 Test results of high - temperature thermal stability performance of PVC films prepared in Application Example 1, Application Example 2 and Comparative Example 1 of the present invention.

[0032] Figure 14 Cytotoxicity test results of ESO, EPO - SFAP and EPO - SFATB of the present invention. Detailed implementation manners

[0033] The present invention will be further described in detail below with reference to the accompanying drawings, but the implementation manners of the present invention are not limited thereto. The raw materials and reagents involved in the following examples can be obtained from commercial channels.

[0034] Figure 1 The synthetic route of the vegetable oil - based PVC plasticizer of the present invention is shown. Soybean oil is obtained by saponification hydrolysis reaction to get soybean oleic acid, and then under the conditions of N,N,N',N' - tetramethylchloroformamidinium hexafluorophosphate (TCFH) and pyridine (Pyr), the compound with aromatic ring and phenolic hydroxyl group reacts with soybean oleic acid through esterification reaction to obtain a colorless oil with a rigid benzene ring structure and a flexible long - chain fatty acid ester part. Finally, the double bond on the long - chain fatty acid ester is epoxidized by meta - chloroperoxybenzoic acid (m - CPBA) to obtain the vegetable oil - based PVC plasticizer of the present invention. The vegetable oil - based PVC plasticizer of the present invention has a "rigid core - flexible arm" molecular structure. Its chemical means introduce a rigid aromatic ring core with different conjugation strengths and electron cloud densities, replace the original glycerol skeleton of the vegetable oil, retain the existing flexible fatty acid long chain, directly synthesize in - situ a vegetable oil derivative with a rigid - flexible structure, and further improve its polarity through epoxidation reaction.

[0035] It should be noted that the above is only one implementation mode of the present invention. The soybean oil can be replaced with vegetable oils having double bonds and ester structures, such as linseed oil and palm oil. Compounds having an aromatic ring and phenolic hydroxyl groups can be selected from phloroglucinol, 2,4,6-tris(4-hydroxyphenyl)-1,3,5-triyltri-phenol, 2,4,6-tris(4-hydroxyphenyl)-s-triazine, 4,4',4''-tricyclo[3.3.1.1 3.7 decane-1,3,5-triyltri-phenol.

[0036] The phloroglucinol, 2,4,6-tris(4-hydroxyphenyl)-1,3,5-triyltri-phenol, 2,4,6-tris(4-hydroxyphenyl)-s-triazine (2,4,6-tris(4-hydroxyphenyl)-1,3,5-triazine), 4,4',4''-tricyclo[3.3.1.1 3.7 decane-1,3,5-triyltri-phenol used in the present invention has the following structural formula: .

[0037] The soybean oil, linseed oil, and palm oil used in the present invention have the following structural formula: .

[0038] Example 1 This example provides a vegetable oil-based PVC plasticizer, which is prepared by the following method: (1) 100 g of soybean oil is mixed with 600 mL of a 95% ethanol solution containing 58.91 g of sodium hydroxide (1.47 mol) and reacted at 70 °C for 2 hours for saponification; after the reaction is completed, 400 mL of distilled water is added for dilution, and 500 mL of ethyl acetate is used for extraction to remove unsaponified matter; the extracted aqueous phase is adjusted to pH 3 with phosphoric acid, filtered, washed with water until neutral, dried over anhydrous sodium sulfate, and finally the solvent is removed by rotary evaporation to obtain a light yellow oily soybean oleic acid product SFA.

[0039] (2) 10.0 g of phloroglucinol, 125.1 g of soybean oleic acid product SFA, and 328.7 g of TCFH are dissolved in acetonitrile, 62.5 g of pyridine is slowly added dropwise to obtain a reaction mixture, and then the reaction mixture is stirred overnight at room temperature, and then diluted with ethyl acetate and the diluted reaction mixture is poured into a saturated aqueous sodium bicarbonate solution. The yellow organic layer is collected, dried over anhydrous sodium sulfate, and then concentrated under reduced pressure. The crude product is subjected to silica gel column chromatography (eluent: n-hexane / ethyl acetate = 100:2), and finally a colorless oil SFAP (35.6 g, and the calculated yield is 45%) is obtained.

[0040] (3) Dissolve the above colorless oil in dichloromethane, and then add m-chloroperoxybenzoic acid (m-CPBA, 24.5 g) in portions. Add an aqueous sodium carbonate solution to this solution to form a two-phase system. After stirring the reaction overnight at room temperature, separate the organic phase and wash it successively with saturated sodium thiosulfate and sodium bicarbonate solutions. After drying over anhydrous magnesium sulfate and filtering through a short column of basic alumina, the colorless liquid product EPO-SFAP is finally obtained.

[0041] Perform nuclear magnetic resonance hydrogen spectrum characterization on the soybean oil fatty acid product SFA, the colorless oil SFAP, and the colorless liquid product EPO-SFAP. The characterization results are as Figures 2 - 4 shown. According to Figure 3 in δ H 6.81(3H, s, Ar-H), 5.43 - 5.29(9H, m, CH 2 =CH 2 ) it is determined that three soybean oil fatty acid chains are successfully grafted onto phloroglucinol. According to Figure 4 in δ H 6.79(3H, s, Ar-H), 3.20 - 2.83(9H, m, CH-O-CH) it is determined that epoxy is successfully obtained as EPO-SFAP. The above results show that the soybean oil fatty acid product SFA and phloroglucinol are successfully synthesized by an esterification reaction and the colorless oil SFAP can be successfully separated by the above preparation method. Then, the epoxy group is successfully introduced onto the carbon-carbon double bond of the colorless oil SFAP by epoxidation with m-CPBA to obtain EPO-SFAP, indicating the successful synthesis of the vegetable oil-based PVC plasticizer.

[0042] Example 2 This example provides a vegetable oil-based PVC plasticizer, which is prepared by the following method: (1) Mix 100 g of soybean oil with 600 mL of a 95% ethanol solution containing 58.91 g of sodium hydroxide (1.47 mol) and react at 70 °C for 2 hours for saponification; after the reaction is completed, add 400 mL of distilled water for dilution, and extract with 500 mL of ethyl acetate to remove the unsaponified matter; adjust the pH of the aqueous phase to 3 with phosphoric acid, filter and wash with water until neutral, dry over anhydrous sodium sulfate, and finally remove the solvent by rotary evaporation to obtain the light yellow oily soybean oil fatty acid product SFA.

[0043] (2) Dissolve 28.0 g of 2,4,6-tris(4-hydroxyphenyl)-1,3,5-triyltriphenol, 125.1 g of soybean oleic acid product SFA, and 328.7 g of TCFH in acetonitrile, and slowly add 62.5 g of pyridine dropwise to obtain a reaction mixture. The reaction mixture was stirred overnight at room temperature, then diluted with ethyl acetate and the diluted reaction mixture was poured into a saturated aqueous sodium bicarbonate solution. The yellow organic layer was collected, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: n-hexane / ethyl acetate = 100:2) to finally obtain a colorless oil, SFATB.

[0044] (3) Dissolve the above-mentioned colorless oil SFATB in dichloromethane, and then add m-chloroperbenzoic acid m-CPBA (24.5 g) in portions. An aqueous sodium carbonate solution was added to the solution to form a two-phase system. After stirring the reaction overnight at room temperature, the organic phase was separated and washed successively with saturated sodium thiosulfate and sodium bicarbonate solutions. After drying over anhydrous magnesium sulfate and filtering through a short column of basic alumina, a colorless liquid product EPO-SFATB was finally obtained.

[0045] The colorless oil SFATB and the colorless liquid product EPO-SFATB were characterized by 1H NMR spectroscopy, and the characterization results are as Figure 5 and Figure 6 shown. According to Figure 5 in δ H 7.73 (3H, s, Ar-H), 7.71 - 7.66 (6H, m, Ar-H), 7.24 - 7.19 (6H, m, Ar-H), 5.45 - 5.32 (9H, m, CH 2 =CH 2 ), it was determined that three soybean oleic acid chains were successfully grafted onto 2,4,6-tris(4-hydroxyphenyl)-1,3,5-triyltriphenol. According to Figure 6 in δ H 7.71 (3H, s, Ar-H), 7.68 - 7.64 (6H, m, Ar-H), 7.21 - 7.18 (6H, m, Ar-H), 3.15 - 2.84 (9H, m, CH-O-CH), it was determined that epoxy was successfully obtained for EPO-SFATB. The above results indicate that the soybean oleic acid product SFA and 2,4,6-tris(4-hydroxyphenyl)-1,3,5-triyltriphenol were successfully synthesized by an esterification reaction, and the colorless oil SFATB could be successfully separated by the above preparation method. Then, an epoxy group was successfully introduced onto the carbon-carbon double bond of the colorless oil SFATB by epoxidation with m-CPBA to obtain EPO-SFATB, indicating that the vegetable oil-based PVC plasticizer was successfully synthesized.

[0046] Example 3 This example provides a vegetable oil-based PVC plasticizer, which is prepared by the following method: (1) 100 g of soybean oil is mixed with 600 mL of a 95% ethanol solution containing 58.91 g of sodium hydroxide (1.47 mol) and reacted at 70 °C for 2 hours for saponification; after the reaction is completed, 400 mL of distilled water is added for dilution, and 500 mL of ethyl acetate is used for extraction to remove the unsaponified matter; the aqueous phase is adjusted to pH 3 with phosphoric acid, filtered, washed with water until neutral, dried over anhydrous sodium sulfate, and finally the solvent is removed by rotary evaporation to obtain a light yellow oily soybean oleic acid product SFA.

[0047] (2) 28.2 g of 2,4,6-tris(4-hydroxyphenyl)-s-triazine, 125.1 g of soybean oleic acid product SFA, and 328.7 g of TCFH are dissolved in acetonitrile, and 62.5 g of pyridine is slowly added dropwise to obtain a reaction mixture. The reaction mixture is stirred overnight at room temperature, then diluted with ethyl acetate and the diluted reaction mixture is poured into a saturated sodium bicarbonate aqueous solution. The yellow organic layer is collected, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The crude product is subjected to silica gel column chromatography (eluent: n-hexane / ethyl acetate = 100:2), and finally a colorless oil SFATT is obtained.

[0048] (3) The above-mentioned colorless oil SFATT is dissolved in dichloromethane, and then meta-chloroperoxybenzoic acid m-CPBA (24.5 g) is added in portions. An aqueous sodium carbonate solution is added to this solution to form a two-phase system. After stirring the reaction overnight at room temperature, the organic phase is separated and washed successively with saturated sodium thiosulfate and sodium bicarbonate solutions. After drying over anhydrous magnesium sulfate and filtering through a short column of basic alumina, a colorless liquid product EPO-SFATT is finally obtained.

[0049] The colorless oil SFATT and the colorless liquid product EPO-SFATT are characterized by nuclear magnetic resonance hydrogen spectrum, and the characterization results are as Figure 7 and Figure 8 shown. According to Figure 7 in δ H 8.80 - 8.73(6H, m, Ar-H), 7.32 - 7.25 (6H, m, Ar-H),5.37(9H, m, CH 2 =CH 2 ) it is determined that three soybean oleic acid chains are successfully grafted onto 2,4,6-tris(4-hydroxyphenyl)-s-triazine. According to Figure 8 in δ H8.77 (6H, m, Ar-H), 7.32 - 7.26 (6H, m, Ar-H), 3.17 - 2.85 (9H, m, CH-O-CH) confirmed the successful epoxidation to obtain EPO-SFATT. The above results indicated that the soybean oleic acid product SFA and 2,4,6-tris(4-hydroxyphenyl)-s-triazine were successfully synthesized through an esterification reaction, and the colorless oily substance SFATT could be successfully separated through the above preparation method. Then, the epoxy group was successfully introduced onto the carbon-carbon double bond of the colorless oily substance SFATT by epoxidation using m-CPBA to obtain EPO-SFATT, demonstrating the successful synthesis of this vegetable oil-based PVC plasticizer.

[0050] Example 4 This example provides a vegetable oil-based PVC plasticizer, which is prepared through the following method: (1) 100 g of soybean oil was mixed with 600 mL of a 95% ethanol solution containing 58.91 g of sodium hydroxide (1.47 mol) and reacted at 70 °C for 2 hours for saponification; after the reaction was completed, 400 mL of distilled water was added for dilution, and the unsaponified matter was removed by extraction with 500 mL of ethyl acetate; the aqueous phase was adjusted to pH 3 with phosphoric acid, filtered, washed with water until neutral, dried over anhydrous sodium sulfate, and finally the solvent was removed by rotary evaporation to obtain a light yellow oily soybean oleic acid product SFA.

[0051] (2) 38.9 g of 4,4',4''-tricyclo[3.3.1.1 3.7 decane-1,3,5-triyltriphenol, 125.1 g of the soybean oleic acid product SFA, and 328.7 g of TCFH were dissolved in acetonitrile, and 62.5 g of pyridine was slowly added dropwise to obtain a reaction mixture. The reaction mixture was stirred overnight at room temperature, then diluted with ethyl acetate and the diluted reaction mixture was poured into a saturated aqueous sodium bicarbonate solution. The yellow organic layer was collected, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: n-hexane / ethyl acetate = 100:2) to finally obtain a colorless oily substance SFATA.

[0052] (3) The above colorless oily substance SFATA was dissolved in dichloromethane, and then m-chloroperoxybenzoic acid m-CPBA (24.5 g) was added in portions. An aqueous sodium carbonate solution was added to this solution to form a two-phase system. After stirring the reaction overnight at room temperature, the organic phase was separated and washed successively with saturated sodium thiosulfate and sodium bicarbonate solutions. After drying over anhydrous magnesium sulfate and filtering through a short column of basic alumina, a colorless liquid product EPO-SFATA was finally obtained.

[0053] The colorless oily substance SFATA and the colorless liquid product EPO-SFATA were characterized by nuclear magnetic resonance hydrogen spectroscopy, and the characterization results are as Figure 9 andFigure 10 As shown. According to Figure 9 δ in H 7.43 - 7.37 (6H, m, Ar - H), 7.07 - 7.01 (6H, m, Ar - H), 5.43 - 5.28 (9H, m, CH 2 =CH 2 ) it is determined that three soybean oleic acid chains are successfully grafted onto 4,4',4'' - tricyclo[3.3.1.1 3.7 decane - 1,3,5 - triyltriphenol. According to Figure 10 δ in H 7.44 - 7.34 (6H, m, Ar - H), 7.10 - 7.01 (6H, m, Ar - H), 3.26 - 2.84 (9H, m, CH - O - CH) it is determined that epoxy is successfully obtained to get EPO - SFATA. The above results show that the soybean oleic acid product SFA is successfully synthesized with 2,4,6 - tris(4 - hydroxyphenyl) - s - triazine through an esterification reaction and the colorless oil SFATA can be successfully separated through the above - mentioned preparation method. Then, m - CPBA is used to successfully introduce an epoxy group onto the carbon - carbon double bond of the colorless oil SFATA through an epoxidation reaction to get EPO - SFATA, indicating that the vegetable - oil - based PVC plasticizer is successfully synthesized.

[0054] Application Example 1 This application example provides the application of the vegetable - oil - based PVC plasticizer in the preparation of PVC films, including the following steps: 1.4 g of PVC is dissolved in THF to obtain a mixed solution with a PVC concentration of 5.0 g / mL. 0.6 g of the vegetable - oil - based PVC plasticizer EPO - SFAP prepared in Example 1 is added, and then it is vigorously stirred at room temperature for 2 h until the solid is completely dissolved to form a uniform and transparent solution. The solution is transferred to a petri dish with a diameter of 6 cm and the petri dish is placed in a vacuum oven for 3 days to remove THF. Subsequently, the petri dish is placed in an oven at 50 °C for 1 day to ensure complete removal of the residual THF, obtaining a PVC film, denoted as PVC - EPO - SFAP.

[0055] Application Example 2 This application example provides the application of the vegetable - oil - based PVC plasticizer in the preparation of PVC films, including the following steps: Dissolve 1.4 g of PVC in THF to obtain a mixed solution with a PVC concentration of 5.0 g / mL. Add 0.6 g of the vegetable oil-based PVC plasticizer EPO-SFATB (content 30%) prepared in Example 2, and then stir vigorously at room temperature for 2 h until the solid is completely dissolved to form a homogeneous and transparent solution. Transfer the solution to a petri dish with a diameter of 6 cm and place the petri dish in a vacuum oven for 3 days to remove THF. Subsequently, place the petri dish in an oven at 50 °C for 1 day to ensure complete removal of residual THF, obtaining a PVC film, denoted as PVC-EPO-SFATB.

[0056] Comparative Example 1 This comparative example prepares a PVC film using epoxidized soybean oil as a PVC plasticizer, including the following steps: Dissolve 1.4 g of PVC in THF, add 0.6 g of epoxidized soybean oil, and then stir vigorously at room temperature for 2 h until the solid is completely dissolved to form a homogeneous and transparent solution. Transfer the solution to a petri dish with a diameter of 6 cm and place the petri dish in a vacuum oven for 3 days to remove THF. Subsequently, place the petri dish in an oven at 50 °C for 1 day to ensure complete removal of residual THF, obtaining a PVC film, denoted as PVC-ESO.

[0057] To compare the influence of the vegetable oil-based PVC plasticizers prepared in Examples 1-2 on the comprehensive properties of PVC films with epoxidized soybean oil, the PVC films prepared in Application Example 1, Application Example 2, and Comparative Example 1 were tested through Experimental Examples 1-3.

[0058] Experimental Example 1 This experimental example conducts mechanical property tests on PVC-EPO-SFAP prepared in Application Example 1, PVC-EPO-SFATB prepared in Application Example 2, and PVC-ESO prepared in Comparative Example 1 (hereinafter referred to as "samples").

[0059] According to GB / T 104.1-2006, use an electronic universal testing machine (E44) to characterize the mechanical properties of the film materials. Test conditions: Measure the tensile strength and elongation at break of the samples at a temperature of 25 °C and a tensile rate of 20 mm / min. The sample specifications are 30 mm×10 mm (length×width). Collect 5 groups of data, calculate, and record the average value. The test results of tensile strength, elongation at break, and toughness are shown in Table 1, and the stress-strain curves of each PVC film are shown in Figure 11 .

[0060] Table 1 Test Results of Mechanical Properties

[0061] From Table 1 and Figure 11It can be seen that the tensile strength, elongation at break, and toughness of PVC-EPO-SFAP and PVC-EPO-SFATB are significantly improved compared to PVC-ESO. Among them, PVC-EPO-SFATB has the highest tensile strength, elongation at break, and toughness. This is because PVC-EPO-SFATB has a larger number of benzene rings and denser π-π stacking, which restricts the thermal movement of PVC molecular chains and improves the strength and toughness of the material. The above results show that compared with epoxy soybean oil as a plasticizer, the vegetable oil-based PVC plasticizer of the present invention has a good plasticizing effect on PVC films. Specifically, the vegetable oil-based PVC plasticizer can significantly improve the mechanical properties of PVC composites, showing a trend of enhancing and toughening the mechanical properties of PVC films.

[0062] Experimental Example 2 In this experimental example, the glass transition temperatures of PVC-EPO-SFAP prepared in Application Example 1, PVC-EPO-SFATB prepared in Application Example 2, and PVC-ESO prepared in Comparative Example 1 (hereinafter referred to as "samples") were tested.

[0063] Use a dynamic thermomechanical analyzer (Netzsch DMA 242E) to characterize the T g of the samples. When testing, the samples were cut into strips with dimensions of 20 mm × 5 mm × 0.4 mm (length × width × thickness). Test procedure: Use liquid nitrogen to lower the temperature to -50 °C, and heat it to 65 °C at a heating rate of 5 °C / min, with a tensile frequency of 1 Hz.

[0064] The test results of the glass transition temperatures of each PVC film are shown in Figure 12 From Figure 12 the glass transition temperatures T g of each sample were obtained, as shown in Table 2.

[0065] Table 2 Glass Transition Temperatures

[0066] From Figure 12 it can be seen that each PVC film only shows a symmetric peak, indicating good compatibility between PVC and the vegetable oil-based PVC plasticizer. From Table 2, it can be seen that the T g of PVC-EPO-SFAP and PVC-EPO-SFATB are both higher than that of PVC-ESO, indicating that the vegetable oil-based PVC plasticizer of the present invention can increase the glass transition temperature of PVC films compared to epoxy soybean oil.

[0067] Experimental Example 3 This experimental example conducts high-temperature stability performance tests on PVC-EPO-SFAP prepared in Application Example 1, PVC-EPO-SFATB prepared in Application Example 2, and PVC-ESO prepared in Comparative Example 1 (hereinafter referred to as "samples").

[0068] During the test, the samples were cut into splines with dimensions of 25 mm × 25 mm × 0.4 mm (length × width × thickness). Test procedure: The samples were placed in a vacuum oven at 180 °C, and the color change of the film materials was observed by recording and taking pictures every 10 minutes.

[0069] The color changes of each PVC film are as Figure 13 shown. As Figure 13 can be seen, PVC-ESO turned yellow at 10 minutes, gradually turned red at 20 minutes, and completely turned black at 140 minutes. PVC-EPO-SFAP gradually turned red at 110 minutes and finally remained reddish-brown until 3 hours, while PVC-EPO-SFATB remained light yellow until 3 hours. The above results indicate that the vegetable oil-based PVC plasticizer synthesized in the present invention can significantly improve the high-temperature stability of PVC films. Among them, PVC-EPO-SFATB has the best effect on improving the high-temperature stability of PVC films because the large volume and rigidity of the benzene ring structure in 2,4,6-tris(4-hydroxyphenyl)-1,3,5-triazine will significantly limit the thermal movement of PVC molecular chains, resulting in restricted molecular chain movement and thus improving its high-temperature performance.

[0070] Experimental Example 4 This experimental example conducts in vitro cytotoxicity experiments on EPO-SFAP prepared in Example 1, EPO-SFATB prepared in Example 2, and ESO (hereinafter referred to as "samples").

[0071] An in vitro cytotoxicity experiment of mouse fibroblasts (L929) was conducted on the samples, and the cell viability was measured using the live / dead cell staining method to evaluate the biocompatibility of the plasticizer.

[0072] L929 cells were inoculated into a 96-well plate and cultured overnight for 24 h. Then, 100 µL of the sample diluted in DMEM medium / serum (concentrations of 10, 5, 1, 0.2, 0.1, and 0.05 mg·ml -1 ) was added and incubated for 24 h. Then, 10 µL of MTT solution (5 mg / mL) was added to each well and incubated for 4 h. After discarding the waste medium and MTT solution, 150 µL of DMSO was added to each well to completely dissolve the formazan crystals, and the measurement was carried out at a wavelength of 490 nm in an enzyme-linked immunosorbent assay (ELISA) reader.

[0073] The results of cell viability are shown inFigure 14 It can be seen from Figure 14 that the cell survival rates of L929 cells treated with samples at different concentrations are all higher than 100% after culture, indicating that the proliferation of L929 cells cultured after treatment with EPO-SFAP, EPO-SFATB and ESO exceeds the initial number. Among them, the effects of samples at different concentrations on the proliferation of L929 cells are different. Specifically, when the sample concentration is 0.1 mg·ml -1 , the cell viability of L929 cells treated with EPO-SFAP and EPO-SFATB is slightly lower than that of L929 cells treated with ESO, indicating that ESO is more conducive to the proliferation of L929 cells than EPO-SFAP and EPO-SFATB at this sample concentration. When the sample concentrations are 10, 0.05 mg·ml -1 , the cell survival rate of L929 cells treated with EPO-SFATB is the highest, indicating that EPO-SFATB is more conducive to the proliferation of L929 cells at this concentration. When the sample concentrations are 5, 1, 0.2 mg·ml -1 , the cell survival rate of L929 cells treated with EPO-SFAP is significantly higher than that of L929 cells treated with ESO, indicating that EPO-SFAP is more conducive to the proliferation of L929 cells at this concentration. The above results show that the vegetable oil-based PVC plasticizer of the present invention is a non-toxic bio-based PVC plasticizer.

[0074] The above are only some embodiments of the present invention. For those of ordinary skill in the art, without departing from the inventive concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. Vegetable oil-based PVC plasticizer, characterized in that: The structural formula of the vegetable oil-based PVC plasticizer is shown in formula (I), formula (II) or formula (III): Formula (I) Formula (II) Formula (III); Wherein, the structure of Ar in the formula (I), formula (II) or formula (III) is , , or .

2. The method for preparing the vegetable oil-based PVC plasticizer according to claim 1, characterized in that: The following steps are involved: (1) subjecting vegetable oil to saponification reaction with a 95% ethanol solution containing sodium hydroxide to obtain a mixed solution, removing unsaponifiable matter from the mixed solution, adjusting the pH value to 3-4 with phosphoric acid, and then separating and purifying the mixed solution, drying the product and removing the solvent to obtain vegetable oleic acid; (2) dissolving vegetable oleic acid, a compound having an aromatic ring and a phenolic hydroxyl group, and N,N,N',N'-tetramethylchloroformamidine hexafluorophosphate in a first organic solvent, then dropping an alkaline catalyst to react, and separating and purifying the reaction product to obtain a first reaction product; (3) dissolving the first reaction product in a second organic solvent, and then sequentially adding an epoxidizing agent and a sodium carbonate solution to obtain a two-phase system; the first reaction product and the epoxidizing agent undergo an epoxidation reaction in the two-phase system, separating the organic phase after the reaction is completed, and separating and purifying the reaction product in the organic phase to obtain; The compound having an aromatic ring and a phenolic hydroxyl group is phloroglucinol, 2,4,6-tris(4-hydroxyphenyl)-1,3,5-triyltriphenol, 2,4,6-tris(4-hydroxyphenyl)-s-triazine or 4,4',4''-tricyclo[3.3.1.1 3.7 ]Decane-1,3,5-triyltriphenol; The vegetable oil is soybean oil, linseed oil or palm oil.

3. The method for preparing a vegetable oil-based PVC plasticizer according to claim 2, characterized in that: In step (1), the molar ratio of the vegetable oil to sodium hydroxide is (0.07-0.1):1; in step (2), the molar ratio of the compound having an aromatic ring and a phenolic hydroxyl group, vegetable oil acid, N,N,N',N'-tetramethylchloroformamidine hexafluorophosphate, and the alkaline catalyst is 1:(4.0-6.0):(10.0-15.0):(9.0-12.0).

4. The method for preparing a vegetable oil-based PVC plasticizer according to claim 2, characterized in that: The epoxidant is meta-chloroperbenzoic acid, and the molar ratio of the epoxidant to the vegetable oil acid is (3.5-5.5):

1.

5. The method for preparing a vegetable oil-based PVC plasticizer according to any one of claims 2 to 4, characterized in that: In step (1), the temperature of the saponification reaction is 65-75°C; In step (2), the temperature for the reaction of adding the alkaline catalyst dropwise is room temperature; In step (3), the temperature of the epoxidation reaction is room temperature.

6. The method for preparing the vegetable oil-based PVC plasticizer according to claim 5, characterized in that: The first organic solvent is acetonitrile, the second organic solvent is selected from at least one of dichloromethane and chloroform; and the alkaline catalyst is selected from at least one of pyridine and N-methylimidazole.

7. The use of the vegetable oil-based PVC plasticizer according to claim 1, characterized in that: The application is the application of the vegetable oil-based PVC plasticizer in the preparation of PVC materials.

8. The use of the vegetable oil-based PVC plasticizer according to claim 7, characterized in that: The PVC material is a food packaging material, a medical and sanitary product or a children's toy.

9. The use of the vegetable oil-based PVC plasticizer according to claim 7 or 8, characterized in that: When the PVC material is a PVC film, it is prepared by the following steps: dissolving PVC in an organic solvent, adding a vegetable oil-based PVC plasticizer, stirring, and drying to remove the organic solvent.

10. The use of the vegetable oil-based PVC plasticizer according to claim 9, characterized in that: The amount of the vegetable oil-based PVC plasticizer used is 20% to 35% of the mass of the PVC film.

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