A composite modified epoxy soybean oil, a preparation method and application thereof, and a modified PVC composite material

Abstract

The application belongs to the technical field of chemical material synthesis, and particularly relates to a composite modified epoxy soybean oil, a preparation method and application thereof, and a modified PVC composite material. Chlorine groups, organic silicon side chains and organic carboxylic acid ester groups are simultaneously grafted into the epoxy soybean oil, the obtained product is in a transparent light yellow viscous liquid state, has the advantages of low acid value, good flame retardance and thermal stability, and has great application potential in the field of green and environment-friendly functional soybean oil-based plasticizer synthesis.

Description

Technical Field

[0001] This invention belongs to the field of chemical material synthesis technology, specifically relating to a composite modified epoxidized soybean oil and its preparation method and application, and a modified PVC composite material. Background Technology

[0002] Polyvinyl chloride (PVC) holds a vital position in many fields, including building materials, wires and cables, artificial leather, and packaging films, due to its excellent mechanical properties, electrical insulation, and corrosion resistance. However, its high rigidity makes it prone to breakage upon impact, necessitating the addition of plasticizers to improve its flexibility and meet the needs of various applications. While traditional phthalate-based small-molecule plasticizers offer excellent plasticizing effects, their bioaccumulation and potential toxicity risks have led to their inclusion in the restricted or banned lists of standards in many countries. Therefore, developing bio-based plasticizer alternatives that combine high compatibility and environmental friendliness has become an important development direction in the chemical industry. Epoxidized soybean oil (ESO), made from renewable natural soybean oil, boasts inherent advantages such as wide availability, biodegradability, and non-toxicity. Furthermore, it exhibits good compatibility and low migration when compounded with PVC, making it an ideal alternative to traditional plasticizers.

[0003] However, although PVC materials possess certain self-extinguishing properties, the introduction of plasticizers without flame-retardant elements, such as epoxidized soybean oil, significantly reduces the flame retardancy rating of the plasticized PVC system. Products made from this system are more easily ignited by a flame source, and the combustion process releases large amounts of toxic hydrogen chloride gas and dense smoke, posing serious safety hazards. Therefore, improving the flame retardancy of plasticized PVC products is crucial for expanding their application range. To this end, the molecular structure of plasticizers is typically modified through multifunctionalization to enhance the system's flame retardancy. By introducing halogens, silane side chains, and organic carboxylic acid ester groups, epoxidized soybean oil plasticizers can be endowed with excellent comprehensive properties, such as flame retardancy and flexibility. Introducing halogens and organosilicones into epoxidized soybean oil plasticizers can interrupt or delay the chain reaction of combustion. During combustion, a protective char layer can form on the surface, further blocking flame and heat transfer, effectively preventing the release of decomposition products during combustion, and inhibiting further thermal decomposition of the material. Introducing organic carboxylic acid ester groups as polar groups can increase the compatibility of the composite modified epoxidized soybean oil with polar polymers such as PVC, improving plasticity. Simultaneously, the partial ring-opening of epoxidized soybean oil by carboxylic acid to form hydroxyl groups provides active sites for subsequent grafting of organosilicon side chains, further improving the grafting effect of organochlorosilanes. However, current multifunctional composite modification processes often suffer from harsh reaction conditions, numerous byproducts, and cumbersome post-processing. Therefore, developing a method for preparing a composite modified epoxidized soybean oil plasticizer with easy process control, sufficient introduction of modifying groups, and high product quality is of significant practical importance. Summary of the Invention

[0004] The purpose of this invention is to provide a composite modified epoxidized soybean oil, its preparation method and application, and a modified PVC composite material, which can solve the shortcomings of the existing multifunctional group composite modification process of epoxidized soybean oil, such as harsh reaction conditions, easy to cause cross-linking and gelation due to violent exothermic reaction, many by-products and high free acid value of the product which can easily damage the downstream catalytic system.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing composite modified epoxidized soybean oil, comprising the following steps: Step 1: Mix epoxidized soybean oil and short-chain organic carboxylic acids, and perform a first reaction and vacuum deacidification sequentially to obtain a modified epoxidized soybean oil intermediate; the acid value of the modified epoxidized soybean oil intermediate is ≤1.5mgKOH / g; Step 2: Mix the modified epoxidized soybean oil intermediate, pyridine, acid catalyst and organochlorosilane, and carry out a second reaction to obtain the composite modified epoxidized soybean oil.

[0006] Preferably, in step 1, the short-chain organic carboxylic acid includes at least one of formic acid, acetic acid, propionic acid, butyric acid, and lactic acid; The molar ratio of the epoxidized soybean oil to the short-chain organic carboxylic acid is 1:0.5~2.5; In step 1, the mixing includes adding short-chain organic carboxylic acids dropwise to epoxidized soybean oil under stirring conditions.

[0007] Preferably, the temperature of the first reaction is 50~90℃ and the time is 4~10h; The acid value of the system obtained after the first reaction satisfies the following condition: 1.5 mg KOH / g < acid value ≤ 3 mg KOH / g.

[0008] Preferably, the protective atmosphere includes nitrogen; The temperature of the vacuum deacidification is 70~110℃, and the temperature of the vacuum deacidification is not lower than the temperature of the first reaction. The vacuum degree of the vacuum deacidification is below -0.09 MPa.

[0009] Preferably, in step 2, the acid catalyst includes at least one of phosphoric acid, sulfuric acid, p-toluenesulfonic acid, fluoroboric acid, and trifluoromethanesulfonic acid; The organochlorosilanes include at least one of trimethylchlorosilane, triethylchlorosilane, triisopropylchlorosilane, triphenylchlorosilane, and methyldiphenylchlorosilane; The molar ratio of the modified epoxidized soybean oil intermediate to pyridine is 1:2~6; The molar ratio of the modified epoxidized soybean oil intermediate to the acid catalyst is 1:0.01~0.04; The molar ratio of the modified epoxidized soybean oil intermediate to the organochlorosilane is 1:2.5~4.5.

[0010] Preferably, in step 2, the mixing includes: premixing the modified epoxidized soybean oil intermediate, pyridine and acid catalyst, and then adding an organochlorosilane dropwise under stirring conditions; During the dropwise addition, the system temperature is 30~70℃; the dropwise addition rate is 2.5~5g / min. The temperature of the second reaction is 30~70℃, and the time is 1~4h.

[0011] Preferably, after the second reaction, a post-treatment is further performed; the post-treatment includes: repeatedly washing the obtained oil phase system with hot water until the aqueous phase is neutral, and then performing vacuum dehydration; The temperature of the hot water is 70~80℃; the mass ratio of the oil phase system to the hot water is 1:1 during each wash; the number of washes is 4~6 times. The vacuum dehydration temperature is 95~120℃, and the time is 0.5~2.5h.

[0012] The present invention also provides a composite modified epoxidized soybean oil prepared by the preparation method described in the above technical solution, wherein the composite modified epoxidized soybean oil uses epoxidized soybean oil as the backbone and simultaneously grafts chlorine groups, organosilicon groups containing silyl ether bonds and organocarboxylic acid ester groups with covalent bonds.

[0013] The present invention also provides the application of the composite modified epoxidized soybean oil described above as a plasticizer in polymer materials.

[0014] The present invention also provides a modified PVC composite material comprising the following components in parts by weight: 100 parts PVC, 30-60 parts plasticizer, and 1.5-3 parts stabilizer; The plasticizer is the composite modified epoxidized soybean oil described in the above technical solution.

[0015] Compared with the prior art, the beneficial effects of the present invention include: (1) Mild reaction, reduced gelation: The innovative stepwise process route of “first using short-chain organic carboxylic acids to partially open the ring in proportion, and then using organochlorosilanes for deep grafting” effectively disperses the intense exothermic reaction when the epoxy groups in the epoxidized soybean oil are concentrated in a high density, making the entire synthesis process stable and mild, and the process conditions are very easy to control, avoiding the risk of “exploding” crosslinking that is very easy to occur in production.

[0016] (2) Excellent flame retardant performance: This invention successfully introduces halogen (chlorine) and silicon elements into the epoxidized soybean oil molecular chain through chemical bonding, achieving highly efficient synergistic flame retardancy. Chlorine releases HCl during combustion, interrupting the combustion chain reaction through a gas-phase free radical capture mechanism; while silicon migrates and accumulates on the material surface, forming a dense silicon carbide protective layer, acting as a solid-phase barrier for heat and oxygen insulation. This achieves highly efficient gas-solid two-phase synergistic flame retardancy, resulting in not only high flame retardant efficiency but also no flame retardant precipitation in polymer products.

[0017] (3) Excellent flexibility: The large volume of organosilicon side chains containing silyl ether bonds and flexible organic carboxylic acid ester groups exert excellent chemical internal plasticizing effect in the long carbon chain skeleton of soybean oil, which greatly improves the low temperature impact resistance and elongation at break of downstream polymer materials.

[0018] (4) Green and environmentally friendly bio-based characteristics: This invention uses renewable epoxidized soybean oil as the main raw material, with a high bio-based content, which conforms to the green chemistry concept of sustainable development. Compared with traditional petroleum-based polyols, this product has a lower carbon footprint throughout its entire life cycle. More importantly, the product has both flame retardancy and flexibility, and can meet a variety of application needs without the need to add petroleum-based flame retardants or plasticizers for physical blending. Attached Figure Description

[0019] Figure 1 This is a synthetic route diagram for the composite modified epoxidized soybean oil in Example 2; Figure 2 The image shows the infrared spectrum of the composite modified epoxidized soybean oil in Example 2. Detailed Implementation

[0020] This invention provides a method for preparing composite modified epoxidized soybean oil, comprising the following steps: Step 1: Mix epoxidized soybean oil and short-chain organic carboxylic acids, and perform a first reaction and vacuum deacidification sequentially to obtain a modified epoxidized soybean oil intermediate; the acid value of the modified epoxidized soybean oil intermediate is ≤1.5mgKOH / g; Step 2: Mix the modified epoxidized soybean oil intermediate, pyridine, acid catalyst and organochlorosilane, and carry out a second reaction to obtain the composite modified epoxidized soybean oil.

[0021] Step 1 of the present invention involves mixing epoxidized soybean oil and short-chain organic carboxylic acids, and sequentially performing a first reaction and vacuum deacidification to obtain a modified epoxidized soybean oil intermediate; the acid value of the modified epoxidized soybean oil intermediate is ≤1.5mgKOH / g.

[0022] In this invention, the short-chain organic carboxylic acid preferably includes at least one of formic acid, acetic acid, propionic acid, butyric acid and lactic acid; the molar ratio of the epoxidized soybean oil and the short-chain organic carboxylic acid is preferably 1:0.5~2.5, specifically 1:0.5, 1:1.0, 1:1.5, 1:2.0, 1:2.5.

[0023] In this invention, step 1, the mixing preferably includes: adding short-chain organic carboxylic acids dropwise to epoxidized soybean oil under stirring conditions. In this invention, the dropwise addition rate is preferably 4-8 g / min, specifically 4 g / min, 4.5 g / min, 5 g / min, 5.5 g / min, 6 g / min, 6.5 g / min, 7 g / min, 7.5 g / min, or 8 g / min.

[0024] In this invention, the preferred temperature for the first reaction is 50-90℃, specifically 50℃, 60℃, 70℃, 80℃, or 90℃; the preferred time is 4-10 hours, specifically 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, or 10 hours; the acid value of the system obtained after the first reaction satisfies the following condition: 1.5 mg KOH / g < acid value ≤ 3 mg KOH / g. In this invention, during the first reaction, it is preferable to sample and measure the acid value every hour until the target value is reached, at which point the reaction is terminated.

[0025] In this invention, the protective atmosphere preferably includes nitrogen; the vacuum deacidification temperature is preferably 70~110℃, specifically 70℃, 80℃, 90℃, 100℃, or 110℃, and the vacuum deacidification temperature is preferably not lower than the temperature of the first reaction; the vacuum degree of the vacuum deacidification is preferably below -0.09MPa; during the vacuum deacidification process, it is preferable to sample and measure the acid value every hour until the desired acid value is reached. In this invention, the vacuum deacidification process preferably further includes filtration.

[0026] After obtaining the modified epoxidized soybean oil intermediate, step 2 of the present invention involves mixing the modified epoxidized soybean oil intermediate, pyridine, acid catalyst, and organochlorosilane to carry out a second reaction, thereby obtaining the composite modified epoxidized soybean oil.

[0027] In this invention, in step 2, the acid catalyst preferably includes at least one selected from phosphoric acid, sulfuric acid, p-toluenesulfonic acid, fluoroboric acid, and trifluoromethanesulfonic acid; the organochlorosilane preferably includes at least one selected from trimethylchlorosilane, triethylchlorosilane, triisopropylchlorosilane, triphenylchlorosilane, and methyldiphenylchlorosilane; the molar ratio of the modified epoxidized soybean oil intermediate to pyridine is preferably 1:2 to 6, specifically 1:2, 1:3, 1:4, 1:5, or 1:6; the molar ratio of the modified epoxidized soybean oil intermediate to the acid catalyst is preferably 1:0.01 to 0.04, specifically 1:0.01, 1:0.02, 1:0.03, or 1:0.04; the molar ratio of the modified epoxidized soybean oil intermediate to the organochlorosilane is preferably 1:2.5 to 4.5, specifically 1:2.5, 1:3, 1:3.5, 1:4, or 1:4.5.

[0028] In this invention, step 2, the mixing preferably includes: premixing the modified epoxidized soybean oil intermediate, pyridine, and acid catalyst, and then adding an organochlorosilane dropwise under stirring conditions; the temperature of the system during the dropwise addition is preferably 30~70℃, specifically 30℃, 40℃, 50℃, 60℃, or 70℃; the dropwise addition rate is 2.5~5 g / min, specifically 2.5 g / min, 2.8 g / min, 3 g / min, 3.5 g / min, 4 g / min, 4.5 g / min, 4.8 g / min, or 5 g / min.

[0029] In this invention, the temperature of the second reaction is preferably 30~70℃, specifically 30℃, 40℃, 50℃, 60℃, or 70℃; the time is 1~4h (the reaction occurs during the dripping process, and the time here refers to the heat preservation time after the dripping is completed), specifically 1h, 2h, 3h, or 4h; the second reaction is preferably carried out under stirring conditions.

[0030] In this invention, after the second reaction, a post-treatment is preferably performed; the post-treatment preferably includes: repeatedly washing the obtained oil phase system with hot water until the aqueous phase is neutral, and then performing vacuum dehydration; the temperature of the hot water is preferably 70~80℃ (specifically 70℃, 75℃, 80℃), and the mass ratio of the oil phase system to water is preferably 1:1 during each washing; the number of repeated washings is preferably 4~6 times; the temperature of the vacuum dehydration is preferably 95~120℃, specifically 95℃, 100℃, 110℃, 120℃; the time is preferably 0.5~2.5h, specifically 0.5h, 1h, 1.5h, 2h, 2.5h.

[0031] In this invention, the mechanism of action of the composite modified epoxidized soybean oil is as follows: (1) Partial Ring Opening (Mild): Using moderately potent short-chain organic carboxylic acids, preferential nucleophilic ring opening is performed on some of the most reactive epoxy groups on the epoxidized soybean oil backbone under mild conditions without the need for additional strong acid catalysts. By strictly controlling the molar ratio, hydroxyl groups and flexible organic carboxylic acid ester groups are quantitatively introduced into the molecular chain in advance. This not only avoids excessive crosslinking and gelation caused by violent exothermic reactions, but also provides basic active sites for subsequent polymer network crosslinking.

[0032] (2) Silane grafting and halogenation: Organochlorosilanes are introduced and pyridine is used as a solvent. Chloride ions act as nucleophiles to attack most of the remaining epoxy groups, anchoring the highly flame-retardant chlorine element to the carbon chain in the form of -C-Cl covalent bonds. At the same time, the large-volume organosilicon not only grafts onto the newly opened ring-opening oxygen anions, but also undergoes silylation reaction with the hydroxyl groups generated in the first step. This dense introduction of large-volume silicon-containing side chains greatly expands the molecular chain spacing, reduces the inter-segment forces, and exerts excellent "internal plasticizing" flexibility.

[0033] (3) Synergistic flame retardant mechanism: When the material is heated and burned, chlorine can capture active free radicals in the gas phase to interrupt the combustion chain reaction; while silicon has extremely low surface free energy, which enables it to spontaneously migrate to the outer surface, enrich and catalyze carbonization, forming a dense silicon-carbon composite heat insulation barrier. The two form an excellent gas-solid two-phase spatial synergistic flame retardant network.

[0034] This invention also provides a composite modified epoxidized soybean oil prepared by the preparation method described above. The composite modified epoxidized soybean oil uses epoxidized soybean oil as its backbone, and simultaneously grafts chlorine groups, organosilicon groups containing silane ether bonds, and organocarboxylic acid ester groups with covalent bonds. In this invention, the composite modified epoxidized soybean oil has an acid value ≤1.5 mgKOH / g, an iodine value ≤2 I2 / 100g, an epoxy value ≥1.8%, and appears as a transparent, pale yellow, viscous liquid.

[0035] The present invention also provides the application of the composite modified epoxidized soybean oil described above as a plasticizer in polymer materials.

[0036] The present invention also provides a modified PVC composite material comprising the following components in parts by weight: 100 parts PVC, 30-60 parts plasticizer, and 1.5-3 parts stabilizer; The plasticizer is the composite modified epoxidized soybean oil described in the above technical solution.

[0037] In this invention, the plasticizer can specifically be in the following weight percentages: 30 parts, 35 parts, 40 parts, 45 parts, 46 parts, 50 parts, 55 parts, or 60 parts. In this invention, the stabilizer preferably includes at least one of barium-zinc stabilizer, calcium-zinc stabilizer, or calcium-magnesium-zinc stabilizer. In this invention, the stabilizer can specifically be in the following weight percentages: 1.5 parts, 2 parts, 2.5 parts, or 3 parts.

[0038] In this invention, the preparation method of the modified PVC composite material preferably includes: mixing the raw materials and then performing open milling; the open milling temperature is preferably 175°C; the open milling is preferably carried out in a two-roll mill.

[0039] Unless otherwise specified, the materials and equipment used in this invention are all commercially available products in the field.

[0040] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0041] Example 1 (1) Add epoxidized soybean oil into the reactor, start stirring, and slowly add lactic acid through the dropper (control the molar ratio of epoxidized soybean oil to lactic acid to be about 1:0.5, and the dropping rate to 4.5 g / min). After the addition is complete, the temperature is raised to 50℃ and the reaction is maintained at that temperature for 10 hours. The acid value is measured every hour until the following condition is met: 1.5 mg KOH / g < acid value ≤ 3 mg KOH / g, at which point the reaction is stopped. Then, high-purity nitrogen is continuously introduced through the bottom of the reactor to adjust the temperature to 70℃, and the vacuum pump is turned on to control the vacuum degree below -0.09 MPa for deacidification under reduced pressure. The acid value is measured every hour until the acid value of the system drops below 1.5 mg KOH / g, at which point the vacuum treatment is stopped, and the modified epoxidized soybean oil intermediate (denoted as intermediate 1) is obtained. (2) In a three-necked flask equipped with a stirrer, thermometer and constant pressure dropping funnel, add the above intermediate 1, pyridine and concentrated sulfuric acid; after stirring and mixing evenly, adjust and keep the temperature of the water bath at 30°C, and slowly and uniformly add triphenylchlorosilane through the constant pressure dropping funnel (keeping the molar ratio of modified epoxidized soybean oil intermediate: pyridine: concentrated sulfuric acid: triphenylchlorosilane at approximately 1:2:0.02:4.5, and the dropping rate at 2.8 g / min), the dropping time is approximately 2 hours. After the dropping is completed, continue to keep the reaction at 30°C for 4 hours to obtain a milky white reaction product; then add deionized hot water at 75°C at an oil-water mass ratio of 1:1, and repeatedly stir and wash the reaction product, and let it stand to separate the aqueous layer; repeat the washing about 4 times until the aqueous phase is neutral, then raise the temperature to 95°C and vacuum for 2 hours. After the reaction product is completely transformed into a light yellow transparent liquid, the composite modified epoxidized soybean oil (denoted as F-ESO-1) is obtained.

[0042] Its acid value was tested to be 1.38 mg KOH / g, epoxy value to be 1.84%, iodine value to be 1.95 I2 / 100g, and viscosity at 25℃ to be 4712 cps.

[0043] Example 2 (1) Add epoxidized soybean oil into the reactor, start stirring, and slowly add formic acid through the dropper (control the molar ratio of epoxidized soybean oil to formic acid to be about 1:1, and the dropping rate to 5g / min). After the addition is complete, the temperature is raised to 60℃ and the reaction is maintained at that temperature for 8 hours. The acid value is measured every hour until the following condition is met: 1.5 mg KOH / g < acid value ≤ 3 mg KOH / g, at which point the reaction is stopped. Then, high-purity nitrogen is continuously introduced through the bottom of the reactor to adjust the temperature to 80℃, and the vacuum pump is turned on to control the vacuum degree below -0.09 MPa for deacidification under reduced pressure. The acid value is measured every hour until the acid value of the system drops below 1.5 mg KOH / g, at which point the vacuum treatment is stopped, and the modified epoxidized soybean oil intermediate (denoted as intermediate 2) is obtained. (2) In a three-necked flask equipped with a stirrer, thermometer and constant pressure dropping funnel, add the above intermediate 2, pyridine and phosphoric acid; after stirring and mixing evenly, adjust and keep the temperature of the water bath at 40°C, and slowly and uniformly add trimethylchlorosilane through the constant pressure dropping funnel (keeping the molar ratio of modified epoxidized soybean oil intermediate: pyridine: phosphoric acid: trimethylchlorosilane at approximately 1:5:0.03:4, and the dropping rate at 3.5 g / min), the dropping time is approximately 2 hours. After the dropping is completed, continue to keep the reaction at 40°C for 3 hours to obtain a milky white reaction product; then add deionized hot water at 75°C at an oil-water mass ratio of 1:1, and repeatedly stir and wash the reaction product, and let it stand to separate the aqueous layer; repeat the washing about 6 times until the aqueous phase is neutral, then raise the temperature to 100°C and vacuum for 1.5 hours. After the reaction product is completely transformed into a light yellow transparent liquid, the composite modified epoxidized soybean oil (denoted as F-ESO-2) is obtained.

[0044] Its acid value was measured to be 1.45 mgKOH / g, epoxy value to be 1.9%, iodine value to be 1.82 I₂ / 100g, and viscosity at 25℃ to be 4880 cps. The synthetic route of this reaction is as follows: Figure 1 As shown.

[0045] Example 3 (1) Add epoxidized soybean oil into the reactor, start stirring, and slowly add acetic acid through the dropper (control the molar ratio of epoxidized soybean oil to acetic acid to be about 1:1.5, and the dropping rate to 5.5 g / min). After the addition is complete, the temperature is raised to 70℃ and the reaction is maintained at this temperature for 6 hours. The acid value is measured every hour until the following condition is met: 1.5 mg KOH / g < acid value ≤ 3 mg KOH / g, at which point the reaction is stopped. Then, high-purity nitrogen is continuously introduced through the bottom of the reactor to adjust the temperature to 90℃, and the vacuum pump is turned on to control the vacuum degree below -0.09 MPa for deacidification under reduced pressure. The acid value is measured every hour until the acid value of the system drops below 1.5 mg KOH / g, at which point the vacuum treatment is stopped, and the modified epoxidized soybean oil intermediate (denoted as intermediate 3) is obtained. (2) In a three-necked flask equipped with a stirrer, thermometer, and constant-pressure dropping funnel, add the above intermediate 3, pyridine, and p-toluenesulfonic acid; after stirring and mixing evenly, adjust and maintain the water bath temperature at 50°C, and slowly and uniformly add triethylchlorosilane through the constant-pressure dropping funnel (maintaining the molar ratio of modified epoxidized soybean oil intermediate:pyridine:p-toluenesulfonic acid:triethylchlorosilane to approximately 1:3:0.01:3.5, with a dropping rate of 4.0 g / min), the dropping time is approximately After the addition is completed, the reaction is continued at 50℃ for 2 hours to obtain a milky white reaction product. Then, deionized hot water at 75℃ is added at an oil-to-water mass ratio of 1:1. The reaction product is repeatedly stirred and washed, and then allowed to stand to separate the aqueous layer. The washing is repeated about 5 times until the aqueous phase is neutral. Then, the temperature is raised to 105℃ and vacuum treatment is carried out for 1.5 hours. After the reaction product is completely transformed into a light yellow transparent liquid, the composite modified epoxidized soybean oil (denoted as F-ESO-3) is obtained.

[0046] Its acid value was tested to be 1.42 mg KOH / g, epoxy value to be 1.93%, iodine value to be 1.77 I2 / 100g, and viscosity at 25℃ to be 4982 cps.

[0047] Example 4 (1) Add epoxidized soybean oil into the reactor, start stirring, and slowly add propionic acid through the dropper (control the molar ratio of epoxidized soybean oil to propionic acid to be about 1:2, and the dropping rate is 6.0 g / min). After the addition is complete, the temperature is raised to 80℃ and the reaction is maintained at this temperature for 5 hours. The acid value is measured every hour until the following condition is met: 1.5 mg KOH / g < acid value ≤ 3 mg KOH / g, at which point the reaction is stopped. Then, high-purity nitrogen is continuously introduced through the bottom of the reactor to adjust the temperature to 100℃. The vacuum pump is turned on and the vacuum degree is controlled below -0.09 MPa for deacidification under reduced pressure. The acid value is measured every hour until the acid value of the system drops below 1.5 mg KOH / g, at which point the vacuum treatment is stopped, and the modified epoxidized soybean oil intermediate (denoted as intermediate 4) is obtained. (2) In a three-necked flask equipped with a stirrer, thermometer, and constant-pressure dropping funnel, add the above intermediate 4, pyridine, and fluoroboric acid; after stirring and mixing evenly, adjust and maintain the water bath temperature at 60℃, and slowly and uniformly add triisopropylchlorosilane through the constant-pressure dropping funnel (maintaining the molar ratio of modified epoxidized soybean oil intermediate: pyridine: fluoroboric acid: triisopropylchlorosilane to approximately 1:4:0.04:3, with a dropping rate of 4.5 g / min), with a dropping time of approximately 2 minutes. After the addition of the product, the reaction was continued at 60℃ for 1.5 hours to obtain a milky white reaction product. Then, deionized hot water at 75℃ was added at an oil-to-water mass ratio of 1:1. The reaction product was repeatedly stirred and washed, and allowed to stand to separate the aqueous layer. The washing was repeated about 6 times until the aqueous phase was neutral. Then, the temperature was raised to 110℃ and vacuumed for 1 hour. After the reaction product was completely transformed into a light yellow transparent liquid, the composite modified epoxidized soybean oil (denoted as F-ESO-4) was obtained.

[0048] Its acid value was tested to be 1.31 mg KOH / g, epoxy value to be 1.89%, iodine value to be 1.83 I2 / 100g, and viscosity at 25℃ to be 4725 cps.

[0049] Example 5 (1) Add epoxidized soybean oil into the reactor, start stirring, and slowly add butyric acid through the dropper (control the molar ratio of epoxidized soybean oil to butyric acid to be about 1:2.5, and the dropping rate to 6.5 g / min). After the addition is complete, the temperature is raised to 90℃ and the reaction is maintained at that temperature for 4 hours. The acid value is measured every hour until the following condition is met: 1.5 mg KOH / g < acid value ≤ 3 mg KOH / g, at which point the reaction is stopped. Then, high-purity nitrogen is continuously introduced through the bottom of the reactor to adjust the temperature to 110℃. The vacuum pump is turned on and the vacuum degree is controlled below -0.09 MPa for deacidification under reduced pressure. The acid value is measured every hour until the acid value of the system drops below 1.5 mg KOH / g, at which point the vacuum treatment is stopped, and the modified epoxidized soybean oil intermediate (denoted as intermediate 5) is obtained. (2) In a three-necked flask equipped with a stirrer, thermometer, and constant-pressure dropping funnel, add the above intermediate 5, pyridine, and trifluoromethanesulfonic acid; after stirring and mixing evenly, adjust and maintain the water bath temperature at 70°C, and slowly and uniformly add methyldiphenylchlorosilane through the constant-pressure dropping funnel (maintaining the molar ratio of modified epoxidized soybean oil intermediate:pyridine:trifluoromethanesulfonic acid:methyldiphenylchlorosilane to approximately 1:6:0.03:3.5, with a dropping rate of 4.8 g / min). The reaction lasted approximately 2 hours. After the addition was complete, the reaction was continued at 70°C for 1 hour to obtain a milky white reaction product. Then, deionized hot water at 75°C was added at an oil-to-water mass ratio of 1:1. The reaction product was repeatedly stirred and washed, and allowed to stand to separate the aqueous layer. The washing was repeated approximately 6 times until the aqueous phase was neutral. Subsequently, the temperature was raised to 110°C and vacuum treatment was performed for 1 hour. After the reaction product was completely transformed into a pale yellow transparent liquid, the composite modified epoxidized soybean oil (denoted as F-ESO-5) was obtained.

[0050] Its acid value was tested to be 1.35 mg KOH / g, epoxy value to be 2.01%, iodine value to be 1.72 I2 / 100g, and viscosity at 25℃ to be 5033 cps.

[0051] Example 6 Accurately weigh 100 parts by weight of PVC, 46 parts by weight of the modified epoxidized soybean oil F-ESO from the above examples, and 1.5 parts by weight of calcium-zinc stabilizer. Then, plasticize and mold the above mixture using a two-roll mill at a temperature of 175°C. The resulting composite materials are sequentially named F-ESO-1PVC, F-ESO-2PVC, F-ESO-3PVC, F-ESO-4PVC, and F-ESO-5PVC.

[0052] Comparative Example 1 Accurately weigh 100 parts by weight of PVC, 46 parts by weight of unmodified epoxidized soybean oil 01R, and 1.5 parts by weight of calcium-zinc stabilizer. Then, plasticize and mold the above mixture using a two-roll mill at a temperature of 175°C.

[0053] Comparative Example 2 Accurately weigh 100 parts by weight of PVC, 46 parts by weight of dioctyl terephthalate (DOTP, a commercially available plasticizer), and 1.5 parts by weight of calcium-zinc stabilizer. Then, plasticize and mold the above mixture using a two-roll mill at a temperature of 175°C.

[0054] Comparative Example 3 Accurately weigh 100 parts by weight of PVC, 46 parts by weight of trioctyl trimellitate TOTM (commercially available plasticizer), and 1.5 parts by weight of calcium zinc stabilizer. Then, plasticize and mold the above mixture using a two-roll mill at a temperature of 175°C.

[0055] Performance testing Test Example 1 Figure 2 The infrared spectrum of the final product obtained in Example 2 shows that: in the spectral curve of the composite modified epoxidized soybean oil plasticizer, 2925 cm⁻¹ -1 The absorption peak at 2852 cm⁻¹ is attributed to the CH asymmetric stretching vibrations of -CH₃ and -CH₂-. -1 The absorption peak at 1743 cm⁻¹ is attributed to the CH symmetric stretching vibrations of -CH₃ and -CH₂-. -1 The absorption peak is the C=O stretching vibration absorption peak of the ester carbonyl group, at 1462 cm⁻¹. -1 The absorption peak corresponding to the CH asymmetric bending vibration of -CH3 and -CH- is at 1375 cm⁻¹. -1 The absorption peaks corresponding to the CH symmetric bending vibrations of -CH3 and -CH2- are at 1250 cm⁻¹. -1 The absorption peak is attributed to the asymmetric stretching vibration of the ester single bond COC, at 1159 cm⁻¹. -1 The absorption peak attributable to the symmetric stretching vibration of the ester single bond COC indicates that an ester group was formed after the organic acid reacted with epoxidized soybean oil. (1095 cm⁻¹) -1 The absorption peak appearing at 859 cm⁻¹ is the stretching vibration absorption peak of Si-OC. -1 The peak at 752 cm⁻¹ is an overlap of the characteristic peaks of the stretching vibrations of Si-(CH₃)₃ and epoxy groups. -1 The characteristic peak of the stretching vibration of C-Cl appeared nearby, which is attributed to the successful grafting of trimethylchlorosilane.

[0056] Test Example 2 To verify the practical application effectiveness of the composite modified epoxidized soybean oil prepared in this invention as a plasticizer, the plasticizer was introduced into PVC materials, and application performance comparison experiments were conducted between Example 6 and Comparative Examples 1-3. Before the experiments, the samples needed to be cut into strips conforming to the corresponding standards.

[0057] (a) Tensile property test: Tensile strength and elongation at break shall be tested in accordance with GB / T 1040.1-2025. The sample shall be prepared into the shape commonly used for tensile testing, placed on the test machine fixture, and the long axis of the sample shall be aligned with the axis of the test machine. The fixture shall be tightened to prevent the sample from moving. Then the test shall be carried out at a tensile rate of 100 mm / min. The results are shown in Table 1.

[0058] Table 1 Tensile properties of each sample

[0059] As can be seen from Table 1, compared with other comparative examples, the sample F-ESO-PVC corresponding to the embodiment has... The elongation at break was improved, mainly because the introduction of silicone side chains containing ether bonds and organic carboxylic acid ester groups through chemical reaction effectively enhanced the compatibility and plasticizing efficiency of the plasticizer with PVC, and improved the lubrication effect between PVC molecular chains. The tensile yield stress of F-ESO-PVC was not significantly different from that of the other comparative examples, with the maximum force slightly lower than that of comparative example 1 and the tensile strength slightly lower than that of comparative example 3.

[0060] (ii) Dynamic thermal stability test: F-ESO-PVC and the plasticized PVC mixtures of comparative examples 1 to 3 were plasticized and molded on a two-roll mill. The time when the material began to stick to the rollers and could not be pulled out into sheets during the plasticization process (i.e., the processing time) was recorded. The test results are shown in Table 2.

[0061] Table 2 Dynamic thermal stability and flame retardant properties of different plasticized PVC products

[0062] As shown in Table 2, in the dynamic thermal stability test, the processable time of F-ESO-PVC was greater than that of the other three comparative examples. Among them, the processable time of the PVC product plasticized with F-ESO-2 prepared by Example 2 of the present invention was 113 min, which showed long-lasting heat resistance during processing. This was 17 min longer than that of the PVC product with unmodified epoxidized soybean oil as plasticizer in Comparative Example 1, and 33 min longer than that of the PVC product with TOTM as plasticizer in Comparative Example 3. Comparative Example 2 showed the lowest processable time, at 73 min, which was only 64.6% of that of F-ESO-2PVC.

[0063] (III) Limiting Oxygen Index (LOI): The test was conducted according to "GB / T 2406.2-2009 Determination of Combustion Behavior by Oxygen Index Method for Plastics - Part 2: Room Temperature Test". The sample size was 100mm × 10mm × 10mm. The test results are shown in Table 2. Generally, a limiting oxygen index (LOI) of 27 or higher is considered sufficient for flame-retardant materials to exhibit good flame-retardant properties. Polyvinyl chloride (PVC) itself has a high chlorine content, making it an excellent flame-retardant material. However, the addition of flammable plasticizers reduces its flame-retardant performance. In Table 2, Comparative Examples 1 and 2, using unmodified epoxidized soybean oil and DOTP (without flame-retardant components) as plasticizers, have LIO indices of only 21.8 and 23.5, respectively, indicating easy combustion in air. However, with the grafting of chlorine atoms and silicone side chains containing ether bonds (F-ESO-PVC), the LIO index of the material significantly increases, reaching a maximum of 28.3, slightly higher than Comparative Example 3, which uses TOTM as a plasticizer. This indicates that the product has high flame-retardant efficacy and broad application prospects. This is mainly attributed to the release of HCl during combustion, which can interrupt the combustion chain reaction by capturing free radicals in the air. In addition, silicon-containing compounds decompose at high temperatures to form a glass-like substance that covers the surface of the burning material, acting as a char layer and enhancing the strength and thermal stability of the char layer, thereby improving the flame-retardant properties of the material.

[0064] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, not all embodiments. Other embodiments can be obtained based on these embodiments without creative intent, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing composite modified epoxidized soybean oil, characterized in that, Includes the following steps: Step 1: Mix epoxidized soybean oil and short-chain organic carboxylic acids, and perform a first reaction and vacuum deacidification sequentially to obtain a modified epoxidized soybean oil intermediate; the acid value of the modified epoxidized soybean oil intermediate is ≤1.5mgKOH / g; Step 2: Mix the modified epoxidized soybean oil intermediate, pyridine, acid catalyst and organochlorosilane, and carry out a second reaction to obtain the composite modified epoxidized soybean oil.

2. The preparation method according to claim 1, characterized in that, In step 1, the short-chain organic carboxylic acid includes at least one of formic acid, acetic acid, propionic acid, butyric acid, and lactic acid; The molar ratio of the epoxidized soybean oil to the short-chain organic carboxylic acid is 1:0.5~2.5; In step 1, the mixing includes adding short-chain organic carboxylic acids dropwise to epoxidized soybean oil under stirring conditions.

3. The preparation method according to claim 1, characterized in that, The temperature of the first reaction is 50~90℃, and the time is 4~10h; The acid value of the system obtained after the first reaction satisfies the following condition: 1.5 mg KOH / g < acid value ≤ 3 mg KOH / g.

4. The preparation method according to claim 1, characterized in that, The protective atmosphere includes nitrogen; The temperature of the vacuum deacidification is 70~110℃, and the temperature of the vacuum deacidification is not lower than the temperature of the first reaction. The vacuum degree of the vacuum deacidification is below -0.09 MPa.

5. The preparation method according to claim 1, characterized in that, In step 2, the acid catalyst includes at least one of phosphoric acid, sulfuric acid, p-toluenesulfonic acid, fluoroboric acid, and trifluoromethanesulfonic acid. The organochlorosilanes include at least one of trimethylchlorosilane, triethylchlorosilane, triisopropylchlorosilane, triphenylchlorosilane, and methyldiphenylchlorosilane; The molar ratio of the modified epoxidized soybean oil intermediate to pyridine is 1:2~6; The molar ratio of the modified epoxidized soybean oil intermediate to the acid catalyst is 1:0.01~0.04; The molar ratio of the modified epoxidized soybean oil intermediate to the organochlorosilane is 1:2.5~4.

5.

6. The preparation method according to claim 1 or 5, characterized in that, In step 2, the mixing includes: premixing the modified epoxidized soybean oil intermediate, pyridine and acid catalyst, and then adding organochlorosilane dropwise under stirring conditions; During the dropwise addition, the system temperature is 30~70℃; the dropwise addition rate is 2.5~5g / min. The temperature of the second reaction is 30~70℃, and the time is 1~4h.

7. The preparation method according to claim 1, characterized in that, Following the second reaction, a post-processing step is performed; the post-processing includes: repeatedly washing the obtained oil phase system with hot water until the aqueous phase is neutral, and then performing vacuum dehydration; The temperature of the hot water is 70~80℃; the mass ratio of the oil phase system to the hot water is 1:1 during each wash; the number of washes is 4~6 times. The vacuum dehydration temperature is 95~120℃, and the time is 0.5~2.5h.

8. The composite modified epoxidized soybean oil prepared by the preparation method according to any one of claims 1 to 7, characterized in that, The composite modified epoxidized soybean oil uses epoxidized soybean oil as the backbone, and simultaneously grafts chlorine groups, organosilicon groups containing silyl ether bonds, and organocarboxylic acid ester groups with covalent bonds.

9. The application of the composite modified epoxidized soybean oil of claim 8 as a plasticizer in polymer materials.

10. A modified PVC composite material, characterized in that, The components include the following parts by mass: 100 parts PVC, 30-60 parts plasticizer, and 1.5-3 parts stabilizer; The plasticizer is the composite modified epoxidized soybean oil as described in claim 8.

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