A bio-based ester plasticizer modified polyester composition, and a preparation method and application thereof

Abstract

This invention discloses a bio-based ester plasticizer-modified polyester composition, its preparation method, and its application, belonging to the field of polymer processing aids technology. The bio-based ester plasticizer-modified polyester composition of this invention comprises 70-95 wt% polyester material and 5-30 wt% bio-based ester plasticizer. The structure of the bio-based ester plasticizer used is shown below. This plasticizer has a high boiling point, good stability, and is non-toxic and environmentally friendly, making it a perfect substitute for traditional phthalate plasticizers. Applying this plasticizer to plasticized polyester materials improves the compatibility of the plasticized polyester material, giving it excellent processing performance. Furthermore, the tensile strength, elongation at break, thermal stability, and migration resistance of this plasticized polyester material are all better than those of plasticized polyester materials plasticized with phthalate plasticizers.

Description

Technical Field

[0001] This invention belongs to the field of polymer processing aids technology, and in particular relates to a bio-based ester plasticizer modified polyester composition, its preparation method and application. Background Technology

[0002] In recent years, polyester materials derived from biomass resources, such as polylactic acid (PLA), polyglycolic acid (PGA), polyhydroxyalkanoates (PHA), and polybutylene succinate (PBS), have been widely used in packaging, biomedicine, textiles, and many other fields due to their numerous advantages, including biodegradability, good biocompatibility, and excellent mechanical properties. However, the inherent rigidity and brittleness of these polyester materials significantly limit their application in the plastics industry, necessitating the addition of plasticizers during processing to improve their toughness. The addition of plasticizers can reduce intermolecular forces and glass transition temperature, enhancing the flexibility and processability of polymer materials. Phthalate and terephthalate derivatives are currently the most commonly used plasticizers, accounting for approximately 80% of the total usage. However, in recent years, concerns about their potential toxicity have raised concerns about their threat to human health and the environment, leading to their ban in developed countries such as the European Union. Therefore, developing new green bio-based plasticizers using biomass resources has enormous market potential and significant practical importance for enriching the variety of plasticizers, promoting the replacement of traditional petroleum-based plasticizers with bio-based plasticizers, gradually expanding the application scope of bio-based plasticizers, and adapting to the future development trend of the polymer material functional additives industry.

[0003] Fatty acid esters are derivatives of oils and fats. Due to their potential use as automotive fuels, they have long been a research hotspot. However, their use as plasticizers in polyester materials presents several problems: low boiling points leading to volatilization during processing; large addition amounts resulting in a significant decrease in product tensile strength; and poor compatibility leading to easy migration and precipitation on surfaces. Therefore, they can only be added in small amounts as auxiliary plasticizers.

[0004] CN117986692A discloses an environmentally friendly plasticizer containing acetoxy fatty acid methyl esters. The process involves preparing a mixture of hydroxyl fatty acid methyl esters by sulfonating refined diesel fuel with sulfuric acid followed by hydrolysis; then, acetylation with acetic anhydride under a catalyst to obtain another mixture containing acetoxy fatty acid methyl esters; after purification and separation, an upper oil layer is obtained; and the oil layer is then cleaned to obtain the final product. However, this environmentally friendly plasticizer has low thermal stability and its mechanical properties are not particularly outstanding.

[0005] CN110627643A discloses a method for preparing environmentally friendly plasticizers from waste oils. This invention uses purified higher fatty acids from waste oils, methanol, 50% hydrogen peroxide, trimellitic anhydride, and acetic anhydride as main raw materials. Through a four-step reaction involving esterification, epoxidation, ring-opening esterification, and acetylation, the molecular structure is modified and functional groups are transformed to obtain the environmentally friendly plasticizer product, acetylated fatty acid methyl ester-trimethacrylate. The environmentally friendly plasticizer product prepared by this invention possesses the characteristics of both cyclic and linear molecular combinations. The product has moderate viscosity, a yellow color, and good migration and heat resistance, making it suitable for industrial production and potentially a replacement for traditional phthalic acid plasticizers. However, this type of plasticizer has a relatively large molecular weight teracetic acid ester structure. The steric hindrance of the teracetic acid ester structure results in plasticized products with high rigidity but poor flexibility and insufficient mechanical properties. Furthermore, trimellitic anhydride is not a bio-based raw material, leading to a relatively large molecular weight and viscosity of the resulting plasticizer. Summary of the Invention

[0006] [Technical Issues]

[0007] This addresses the problems of poor compatibility, high viscosity, and insufficient thermal stability and mechanical properties in polyester materials using existing plasticizers.

[0008] [Technical Solution]

[0009] This invention provides a method for preparing and applying a bio-based ester plasticizer-modified polyester composition. The plasticized polyester material of this invention exhibits excellent plasticizing effects while maintaining good mechanical properties. Specifically, it employs a bio-based ester plasticizer containing long aliphatic chain structures, benzene ring structures, polyester group structures, and short ester branched chain structures, which possesses unique plasticizing properties.

[0010] The first objective of this invention is to provide a bio-based ester plasticizer modified polyester composition, the raw materials of which include 70-95 wt% polyester material and 5-30 wt% bio-based ester plasticizer;

[0011] The structure of the bio-based ester plasticizer is shown in the following general formula:

[0012]

[0013] In the formula, R1 is C 1-10 alkyl;

[0014] n1 is the number of -CH2- on the fatty chain, which can be 1, 2, 3, 4, 5, 6, 7 or 8;

[0015] n2 is the number of substituents R2 on the benzene ring, which can be 1, 2, 3 or 4;

[0016] Each R2 is independently selected from -O-C1-4 alkyl, -O-CO-C1-4 alkyl;

[0017] n3 represents the number of -CH2- atoms on the fatty chain, which can be 1, 2, 3, 4, 5, 6, 7, or 8.

[0018] n4 represents the number of -CH2- atoms on the fatty chain, which can be 1, 2, 3, 4, 5, 6, 7, or 8.

[0019] n5 represents the number of -CH2- atoms on the fatty acid chain, which can be 1, 2, 3, 4, 5, 6, 7, or 8.

[0020] In embodiments of the present invention, at least one -O-CO-C molecule is present on the benzene ring. 1-4 Alkyl substitution.

[0021] In embodiments of the present invention, the structure of the bio-based plasticizer may specifically be:

[0022]

[0023] R1 is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, or decyl.

[0024] R2, R3, R4, and R5 are each independently selected from methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, tert-butoxy, acetoxy, propionyloxy, and butyryloxy, with the remainder being hydrogen.

[0025] In embodiments of the present invention, at least one of R2, R3, R4, and R5 is selected from -O-CO-C. 1-4 Alkyl substitution; the remainder is any selection from: hydrogen, -O-C1-4 alkyl, or -O-CO-C 1-4 Alkyl substitution.

[0026] In an embodiment of the present invention, at least one of R2, R3, R4, and R5 is selected from acetoxy; the rest are hydrogen or methoxy.

[0027] In one embodiment of the present invention, the preparation method of the bio-based ester plasticizer includes: firstly, preparing an epoxy fatty acid ester by means of an epoxidation reaction using fatty acid ester and catalyst 1 as raw materials; then preparing a fatty acid ester-organic acid ester by means of an epoxidation reaction using the epoxy fatty acid ester, natural organic acid and ring-opening agent; and finally obtaining a bio-based ester plasticizer by means of an acetylation reaction using the fatty acid ester-organic acid ester, acetic anhydride and catalyst 2.

[0028] In one embodiment of the present invention, the fatty acid ester is a fatty acid ester containing 1 to 3 unsaturated double bonds, specifically selected from at least one of the following: methyl oleate, ethyl oleate, butyl oleate, hexyl oleate, octyl oleate, decyl oleate, methyl linoleate, ethyl linoleate, butyl linoleate, hexyl linoleate, octyl linoleate, decyl linoleate, methyl linolenic acid, ethyl linolenic acid, butyl linolenic acid, hexyl linolenic acid, octyl linolenic acid, and decyl linolenic acid.

[0029] In one embodiment of the present invention, the natural organic acid is at least one selected from salicylic acid, vanillic acid, syringic acid, gentianic acid, protocatechuic acid, and gallic acid.

[0030] In an embodiment of the present invention, the catalyst 1 is any one of m-chloroperoxybenzoic acid and hydrogen peroxide.

[0031] In embodiments of the present invention, the ring-opening agent is either tetrabutylammonium chloride or tetrabutylammonium bromide.

[0032] In an embodiment of the present invention, the catalyst 2 is either a strong acid cation exchange resin or concentrated sulfuric acid.

[0033] In one embodiment of the present invention, in the epoxidation reaction, the molar ratio of fatty acid ester and intercatalyst 1 is 1:1.2 to 3.2.

[0034] In one embodiment of the present invention, the specific steps of the epoxidation reaction are as follows: fatty acid ester and m-chloroperoxybenzoic acid are dissolved in dichloromethane, reacted in an ice-water bath and then at room temperature, and the product epoxidized fatty acid ester is obtained after neutralization, purification and drying.

[0035] In one embodiment of the present invention, the specific steps of the epoxidation reaction are as follows: adding acidic ion exchange resin and formic acid to a fatty acid ester, and then adding hydrogen peroxide dropwise to react and obtain an epoxy fatty acid ester.

[0036] In one embodiment of the present invention, in the ring-opening reaction, the molar ratio of epoxy fatty acid ester to natural organic acid is 1:1.4 to 4.5.

[0037] Furthermore, if the fatty acid ester is a fatty acid ester containing one unsaturated double bond, the molar ratio of epoxidized fatty acid ester to natural organic acid is 1:1.4 to 2.5; if the fatty acid ester is a fatty acid ester containing two unsaturated double bonds, the molar ratio of epoxidized fatty acid ester to natural organic acid is 1:2.0 to 3.5; if the fatty acid ester is a fatty acid ester containing three unsaturated double bonds, the molar ratio of epoxidized fatty acid ester to natural organic acid is 1:3.0 to 4.5.

[0038] In one embodiment of the present invention, the specific steps of the ring-opening reaction are as follows: the epoxy fatty acid ester, the natural organic acid and the ring-opening agent are reacted continuously at 120-140°C for 4-7 hours. After the reaction is completed, the mixture is washed until neutral, purified and dried to obtain the fatty acid ester-organic acid ester.

[0039] In embodiments of the present invention, during the ring-opening reaction, the amount of ring-opening agent added is 0.1 wt% to 5 wt% of the mass of the epoxy fatty acid ester. More preferably, it is 4 wt% to 5 wt%.

[0040] In one embodiment of the present invention, the amount of acetic anhydride added in the acetylation reaction is 50% to 90% of the fatty acid ester-organic acid ester.

[0041] In one embodiment of the present invention, in the acetylation reaction, the amount of catalyst 2 added is 5 wt% to 15 wt% of fatty acid ester-organic acid ester.

[0042] In one embodiment of the present invention, the specific steps of the acetylation reaction are as follows: acetic anhydride, fatty acid ester-organic acid ester and catalyst 2 are reacted continuously at 60℃~90℃ for 10~24h. After the reaction is completed, the mixture is washed until neutral, purified and dried to obtain the bio-based lipid plasticizer.

[0043] In one embodiment of the present invention, the polyester material is one or more of polylactic acid, polyglycolic acid, polyhydroxyalkanoate, polybutylene succinate, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, and polyethylene furanate.

[0044] A second objective of this invention is to provide a method for preparing the above-mentioned bio-based ester plasticizer-modified polyester composition, comprising the following steps:

[0045] Polyester materials and bio-based ester plasticizers are added to a screw extruder or torque rheometer for melt blending, and then processed through a molding process to obtain plasticized polyester materials with excellent comprehensive performance.

[0046] In one embodiment of the present invention, the melt blending temperature is 140-240°C and the time is 6-10 min.

[0047] The melt blending temperature is 5-80℃ above the melting point of the polyester material.

[0048] The present invention also provides the application of the above-mentioned bio-based ester plasticizer modified polyester composition in the fields of packaging, construction, automobiles, biopharmaceutical preparation, textiles or electronics.

[0049] [Beneficial Effects]

[0050] (1) The present invention prepares a plasticizer with a long aliphatic chain structure, a benzene ring structure, a polyester group structure, and a short ester branched chain structure; the plasticizer is applied to plasticized polyester materials to improve the compatibility of the plasticized polyester materials and make them have excellent processing performance. Furthermore, the tensile strength, elongation at break, thermal stability and migration resistance of the plasticized polyester materials are better than those of plasticized polyester materials plasticized with phthalic plasticizers.

[0051] (2) The non-polar long alkyl chain inserted into the polyester molecule increases the free volume and acts as a lubricant. The presence of the cyclic benzene ring structure improves the compatibility of the plasticizer with the polyester molecule while increasing its thermal stability and mechanical properties. The multiple polar ester groups contained therein form hydrogen bonds with the ester groups on the polyester molecule, which offsets part of the interaction force of the polyester molecule and increases the compatibility with the polyester molecule. In addition, the short ester branch structure increases the interaction and physical penetration between molecules. The migration rate of the plasticizer in the polyester molecule is significantly reduced, and it can replace the traditional phthalate plasticizers.

[0052] (3) The raw materials used in this invention are derived from bio-based materials, which are green and environmentally friendly. Attached Figure Description

[0053] Figure 1 Infrared spectrum of the plasticizer methyl acetooleate-salicylic acid ester product;

[0054] Figure 2 Thermogravimetric curves of plasticizer 1 (acetylated methyl oleate-salicylate) and comparative plasticizers are shown. The comparative plasticizers include: methyl oleate, plasticizer A (benzyl oleate), plasticizer B (acetoxy fatty acid methyl ester), and plasticizer C (acetylated methyl oleate-benzoate). Detailed Implementation

[0055] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0056] Preparation of a series of bio-based ester plasticizers

[0057] Preparation of plasticizer 1:

[0058] (R1=Me, R2=-O-COCH3, R3=R4=R5=H)

[0059] (1) Dissolve 37g of m-chloroperoxybenzoic acid in 150mL of dichloromethane and stir under ice-water bath conditions. Then add 100mL of dichloromethane solution containing 50g of methyl oleate dropwise to the above system. The above raw materials are first reacted in an ice-water bath for 0.5h, and then reacted at room temperature for 24h. After the reaction is complete, wash with sodium thiosulfate solution and sodium bicarbonate solution until neutral, then wash with sodium chloride solution 3 times, and finally wash with deionized water 3 times. Then remove dichloromethane by vacuum distillation under -0.1MPa and 35℃ to obtain the product epoxy methyl oleate.

[0060] (2) 50g (0.16mol) of epoxy methyl oleate, 33g (0.24mol) of salicylic acid and 2g of tetrabutylammonium chloride obtained in step (1) were added to the reactor under a nitrogen atmosphere. The above raw materials were mixed and heated to 140°C and reacted for 5 hours. After the reaction was completed, the mixture was washed with deionized water until neutral. The organic phase was then vacuum distilled at -0.1MPa and 75°C to remove water and obtain the product methyl oleate-salicylic acid ester.

[0061] (3) Add 50g of methyl oleate-salicylate, 35g of acetic anhydride and 2.5g of strong acid cation exchange resin from step (2) to the reactor. Mix the above raw materials and heat to 85°C. Continue the reaction for 24 hours. After the reaction is complete, remove the acetic anhydride by vacuum distillation at -0.1MPa and 120°C. Then wash with deionized water until neutral. Finally, remove the water by vacuum distillation at -0.1MPa and 75°C to obtain the final product, bio-based lipid plasticizer methyl acetooleate-salicylate.

[0062] Infrared spectroscopy was performed on the product methyl acetooleate-salicylate obtained during the preparation process. The test results are as follows: Figure 1 As shown.

[0063] Figure 1 From top to bottom, the sequence consists of epoxy methyl oleate, methyl oleate-salicylate, and the final product, methyl acetylate-salicylate. In the first step of the epoxidation reaction, the methyl oleate infrared spectroscopy curve shows a peak value at 928 cm⁻¹. -1 The formation of the epoxy bond (COC) confirms the successful preparation of epoxy methyl oleate. Subsequently, the stretching vibration peak of the epoxy bond (COC) in the methyl oleate-salicylic acid ester infrared curve disappears, and the peak at 3493 cm⁻¹ disappears. -1 The appearance of the stretching vibration peak of the hydroxyl group (-OH) indicates that the epoxy bond in methyl oleate has been opened. In the final acetylation reaction, the peak at 3493 cm⁻¹... -1 The disappearance of the stretching vibration peak of the hydroxyl group (-OH) indicates that the acetylation reaction was successfully carried out, and the synthesis of methyl acetooleate-salicylic acid ester was successful.

[0064] Preparation of plasticizer 2:

[0065] (R1=Me, R3=OMe, R4=-O-COCH3, R2=R5=H)

[0066] (1) Dissolve 40g of m-chloroperoxybenzoic acid in 150mL of dichloromethane and stir under ice-water bath conditions. Then add 100mL of dichloromethane solution containing 50g of methyl oleate dropwise to the above system. The above raw materials are first reacted in an ice-water bath for 0.5h, and then reacted at room temperature for 24h. After the reaction is complete, wash with sodium thiosulfate solution and sodium bicarbonate solution until neutral, then wash with sodium chloride solution 3 times, and finally wash with deionized water 3 times. Then remove dichloromethane by vacuum distillation under -0.1MPa and 35℃ to obtain the product epoxy methyl oleate.

[0067] (2) 50g (0.16mol) of the product obtained in step (1), 40g (0.24mol) of vanillic acid and 0.1g of tetrabutylammonium chloride were added to the reactor under a nitrogen atmosphere. The above raw materials were mixed and heated to 140°C and reacted for 5 hours. After the reaction was completed, the mixture was washed with deionized water until neutral. The organic phase was then vacuum distilled at -0.1MPa and 75°C to remove water and obtain the product methyl oleate-vanillic acid ester.

[0068] (3) Add 50g of the product from step (2) methyl oleate-vanillate, 25g of acetic anhydride and 5g of strong acid cation exchange resin to the reactor. Mix the above raw materials and heat to 85°C. Continue the reaction for 24 hours. After the reaction is complete, remove the acetic anhydride by vacuum distillation at -0.1MPa and 120°C. Then wash with deionized water until neutral. Finally, remove the water by vacuum distillation at -0.1MPa and 75°C to obtain the final product, bio-based lipid environmentally friendly plasticizer methyl oleate-vanillate.

[0069] Preparation of plasticizer 3:

[0070] (R1=Et, R3=R5=OMe, R4=-O-COCH3, R2=H)

[0071] (1) Dissolve 43g of m-chloroperoxybenzoic acid in 150mL of dichloromethane and stir under ice-water bath conditions. Then add 100mL of dichloromethane solution containing 50g of ethyl oleate dropwise to the above system. The above raw materials are first reacted in an ice-water bath for 0.5h, and then reacted at room temperature for 24h. After the reaction is complete, wash with sodium thiosulfate solution and sodium bicarbonate solution until neutral, then wash with sodium chloride solution 3 times, and finally wash with deionized water 3 times. Then remove dichloromethane by vacuum distillation under -0.1MPa and 35℃ to obtain the product ethyl oleate.

[0072] (2) 50g (0.16mol) of epoxy oleate, 48g (0.24mol) of syringic acid and 1g of tetrabutylammonium chloride obtained in step (1) were added to the reactor under a nitrogen atmosphere. The above raw materials were mixed and heated to 140°C and reacted for 5 hours. After the reaction was completed, the mixture was washed with deionized water until neutral. The organic phase was then vacuum distilled at -0.1MPa and 75°C to remove water and obtain the product oleate-syringic acid ester.

[0073] (3) Add 50g of ethyl oleate-eugenol ester, 40g of acetic anhydride and 7.5g of strong acid cation exchange resin from step (2) into the reactor. Mix the above raw materials and heat to 85°C. Continue the reaction for 24 hours. After the reaction is complete, remove the acetic anhydride by vacuum distillation at -0.1MPa and 120°C. Then wash with deionized water until neutral. Finally, remove the water by vacuum distillation at -0.1MPa and 75°C to obtain the final product, ethyl acetooleate-eugenol ester, a bio-based lipid environmentally friendly plasticizer.

[0074] Preparation of plasticizer 4:

[0075] (R1 = n-butyl, R2 = R5 = -O-COCH3, R3 = R4 = H)

[0076] (1) Dissolve 37g of m-chloroperoxybenzoic acid in 150mL of dichloromethane and stir under ice-water bath conditions. Then add 100mL of dichloromethane solution containing 50g of butyl oleate dropwise to the above system. The above raw materials are first reacted in an ice-water bath for 0.5h, and then reacted at room temperature for 24h. After the reaction is complete, wash with sodium thiosulfate solution and sodium bicarbonate solution until neutral, then wash with sodium chloride solution 3 times, and finally wash with deionized water 3 times. Then remove dichloromethane by vacuum distillation under -0.1MPa and 35℃ to obtain the product epoxy butyl oleate.

[0077] (2) 50g (0.14mol) of the product obtained in step (1), 32.3g (0.21mol) of gentian acid and 2.5g of tetrabutylammonium chloride were added to the reactor under a nitrogen atmosphere. The above raw materials were mixed and heated to 140°C and reacted for 5 hours. After the reaction was completed, the mixture was washed with deionized water until neutral. The organic phase was then vacuum distilled at -0.1MPa and 75°C to remove water and obtain the product oleate butyl ester-gentian ester.

[0078] (3) Add 50g of butyl oleate-gentianate, 35g of acetic anhydride and 5g of strong acid cation exchange resin from step (2) to the reactor. Mix the above raw materials and heat to 85°C. Continue the reaction for 24 hours. After the reaction is complete, remove the acetic anhydride by vacuum distillation at -0.1MPa and 120°C. Then wash with deionized water until neutral. Finally, remove the water by vacuum distillation at -0.1MPa and 75°C to obtain the final product, butyl oleate-gentianate, a bio-based lipid environmentally friendly plasticizer.

[0079] Preparation of plasticizer 5:

[0080] (R1 = hexyl, R3 = R4 = -O-COCH3, R2 = R5 = H)

[0081] (1) Dissolve 37g of m-chloroperoxybenzoic acid in 150mL of dichloromethane and stir under ice-water bath conditions. Then add 100mL of dichloromethane solution containing 50g of hexyl oleate dropwise to the above system. The above raw materials are first reacted in an ice-water bath for 0.5h, and then reacted at room temperature for 24h. After the reaction is complete, wash with sodium thiosulfate solution and sodium bicarbonate solution until neutral, then wash with sodium chloride solution 3 times, and finally wash with deionized water 3 times. Then remove dichloromethane by vacuum distillation under -0.1MPa and 35℃ to obtain the product hexyl oleate.

[0082] (2) 50g (0.13mol) of the product obtained in step (1), 29.2g (0.19mol) of protocatechuic acid and 2g of tetrabutylammonium chloride were added to the reactor under a nitrogen atmosphere. The above raw materials were mixed and heated to 140°C and reacted for 5 hours. After the reaction was completed, the mixture was washed with deionized water until neutral. The organic phase was then vacuum distilled at -0.1MPa and 75°C to remove water and obtain the product oleic acid hexyl ester-protocatechuic acid ester.

[0083] (3) Add 50g of the product from step (2) ethyl oleate-protocatechuate, 35g of acetic anhydride and 5g of strong acid cation exchange resin to the reactor. Mix the above raw materials and heat to 85°C. Continue the reaction for 24 hours. After the reaction is complete, remove the acetic anhydride by vacuum distillation at -0.1MPa and 120°C. Then wash with deionized water until neutral. Finally, remove the water by vacuum distillation at -0.1MPa and 75°C to obtain the final product, ethyl oleate-protocatechuate, a bio-based lipid environmentally friendly plasticizer.

[0084] Preparation of plasticizer 6:

[0085] (R1 = decyl, R2 = H, R3 = R4 = R5 = -O-COCH3)

[0086] (1) Add 0.5g of formic acid and 0.05g of acidic ion exchange resin to 50g of decyl oleate. While stirring, add 35% hydrogen peroxide dropwise over 4 hours. Then react for another hour. After the reaction is complete, cool to below 50°C and wash with sodium carbonate solution and deionized water until neutral. Then remove impurities by vacuum distillation at -0.1MPa and 100°C to obtain the product epoxy decyl oleate.

[0087] (2) 50g (0.11mol) of epoxy oleate decyl ester, 30.6g (0.18mol) of gallic acid and 2g of tetrabutylammonium chloride obtained in step (1) were added to the reactor under a nitrogen atmosphere. The above raw materials were mixed and heated to 140°C and reacted for 5 hours. After the reaction was completed, the mixture was washed with deionized water until neutral. The organic phase was then vacuum distilled at -0.1MPa and 75°C to remove water and obtain the product oleate decyl ester-gallic acid ester.

[0088] (3) Add 50g of decyl oleate-gallate, 35g of acetic anhydride and 7.5g of strong acid cation exchange resin from step (2) to the reactor. Mix the above raw materials and heat to 85°C. Continue the reaction for 24 hours. After the reaction is complete, remove the acetic anhydride by vacuum distillation at -0.1MPa and 120°C. Then wash with deionized water until neutral. Finally, remove the water by vacuum distillation at -0.1MPa and 75°C to obtain the final product, decyl oleate-gallate, a bio-based lipid environmentally friendly plasticizer.

[0089] Preparation of plasticizer 7:

[0090] (R1=Me, R3=R4=-O-COCH3, R2=R5=H)

[0091] (1) Dissolve 80g of m-chloroperoxybenzoic acid in 150mL of dichloromethane and stir under ice-water bath conditions. Then add 100mL of dichloromethane solution containing 50g of methyl linoleate to the above system. The above raw materials are first reacted in an ice-water bath for 0.5h, and then reacted at room temperature for 24h. After the reaction is complete, wash with sodium thiosulfate solution and sodium bicarbonate solution until neutral, then wash with sodium chloride solution 3 times, and finally wash with deionized water 3 times. Then remove dichloromethane by vacuum distillation under -0.1MPa and 35℃ to obtain the product methyl linoleate epoxy.

[0092] (2) 50g (0.16mol) of methyl linoleate, 52.36g (0.34mol) of protocatechuic acid and 2g of tetrabutylammonium chloride obtained in step (1) were added to the reactor under a nitrogen atmosphere. The above raw materials were mixed and heated to 140°C and reacted for 5 hours. After the reaction was completed, the mixture was washed with deionized water until neutral. The organic phase was then vacuum distilled at -0.1MPa and 75°C to remove water and obtain the product methyl linoleate-protocatechuic acid ester.

[0093] (3) Add 50g of the product from step (2) methyl linoleate-protocatechuate, 40g of acetic anhydride and 5g of strong acid cation exchange resin to the reactor. Mix the above raw materials and heat to 85°C. Continue the reaction for 24 hours. After the reaction is complete, remove the acetic anhydride by vacuum distillation at -0.1MPa and 120°C. Then wash with deionized water until neutral. Finally, remove the water by vacuum distillation at -0.1MPa and 75°C to obtain the final product, fatty acid ester-based environmentally friendly plasticizer methyl linoleate-protocatechuate.

[0094] Preparation of plasticizer 8:

[0095] (R1=Me, R2=H, R3=R4=R5=-O-COCH3)

[0096] (1) Dissolve 120g of m-chloroperoxybenzoic acid in 150mL of dichloromethane and stir under ice-water bath conditions. Then add 100mL of dichloromethane solution containing 50g of methyl linoleate to the above system. The above raw materials are first reacted in an ice-water bath for 0.5h, and then reacted at room temperature for 24h. After the reaction is complete, wash with sodium thiosulfate solution and sodium bicarbonate solution until neutral, then wash with sodium chloride solution 3 times, and finally wash with deionized water 3 times. Then remove dichloromethane by vacuum distillation under -0.1MPa and 35℃ to obtain the product methyl linoleate epoxy.

[0097] (2) 50g (0.16mol) of the product methyl linoleate obtained in step (1), 85g (0.50mol) of gallic acid and 1g of tetrabutylammonium chloride were added to the reactor under a nitrogen atmosphere. The above raw materials were mixed and heated to 140°C and reacted for 5 hours. After the reaction was completed, the mixture was washed with deionized water until neutral. The organic phase was then vacuum distilled at -0.1MPa and 75°C to remove water and obtain the product methyl linoleate-gallic acid ester.

[0098] (3) Add 50g of methyl linolenic acid-gallate, 45g of acetic anhydride and 5g of strong acid cation exchange resin from step (2) into the reactor. Mix the above raw materials and heat to 85°C. Continue the reaction for 24 hours. After the reaction is complete, remove the acetic anhydride by vacuum distillation at -0.1MPa and 120°C. Then wash with deionized water until neutral. Finally, remove the water by vacuum distillation at -0.1MPa and 75°C to obtain the final product, fatty acid ester-based environmentally friendly plasticizer methyl linolenic acid-gallate.

[0099] Preparation of polyester compositions

[0100] Examples 1-6

[0101] The preparation steps of plasticizer in polylactic acid (PLA) are as follows:

[0102] Plasticizers were melt-blended with polylactic acid (PLA) at 185°C for 6 minutes using a torque rheometer, and then a plasticized PLA film with excellent comprehensive performance was obtained through a molding process.

[0103] Table 1 Formulation of plasticizers in PLA compositions

[0104]

[0105] Plasticizer A represents benzyl oleate, which can be prepared by the following method: 50g of oleic acid, 18.8g of benzyl alcohol, 0.85g of p-toluenesulfonic acid and 13.5g of toluene are reacted continuously at 130℃ under nitrogen atmosphere for 10-12h. After the reaction is completed, the crude product is washed with NaHCO3 solution and deionized water. Finally, the crude product is distilled under reduced pressure to fully remove the residual water and solvent in the crude product to obtain benzyl oleate.

[0106] Plasticizer B represents the acetoxy fatty acid methyl ester mentioned in existing literature CN117986692A (Example 6 in that literature).

[0107] Plasticizer C was prepared according to the same method as plasticizer 1, except that salicylic acid was replaced with benzoic acid to obtain methyl acetooleate-benzoic acid ester.

[0108] Examples 7-12

[0109] The preparation steps of the plasticizer in polyglycolic acid (PGA) are as follows:

[0110] Plasticizers were melt-blended with polyglycolic acid (PGA) at 240°C for 8 minutes using a torque rheometer, and then a plasticized PGA film with excellent comprehensive performance was obtained through a molding process.

[0111] Table 2 Formulation of plasticizers in PGA compositions

[0112]

[0113] Examples 13-18

[0114] The preparation steps of the plasticizer in polyhydroxyalkanoates (PHA) are as follows:

[0115] Plasticizers were melt-blended with polyhydroxyalkanoates (PHA) at 165°C for 6 minutes using a torque rheometer, and then a plasticized PHA film with excellent comprehensive performance was obtained through a molding process.

[0116] Table 3 Formulation of plasticizers in PHA compositions

[0117]

[0118] Examples 19-24

[0119] The preparation steps of plasticizer in polyethylene terephthalate (PET) are as follows:

[0120] Plasticizers were melt-blended with polyethylene terephthalate (PET) at 240°C for 6 minutes using a torque rheometer, and then a molding process was used to obtain a plasticized PET film with excellent comprehensive performance.

[0121] Table 4 Formulation of plasticizers in PET compositions

[0122]

[0123] Examples 25-30

[0124] The preparation steps of plasticizer in polycarbonate (PC) are as follows:

[0125] Plasticizer and polycarbonate (PC) were melt-blended at 230°C for 6 minutes using a torque rheometer, and then a molding process was used to obtain a plasticized PC film with excellent comprehensive performance.

[0126] Table 5 Formulation of plasticizers in PC compositions

[0127]

[0128] The mechanical properties of the materials were tested according to GB / T 1040-2006, with a tensile rate of 50 mm / min, and five samples were tested in parallel for each group.

[0129] Thermogravimetric analysis was performed on plasticizers and polyester materials using N2 as the carrier gas, at a flow rate of 50 mL / min, a test temperature range of 100–550 °C, a heating rate of 20 °C / min, and a sample mass of 5–10 mg.

[0130] According to the standard "ISO 176-2005 Activated Carbon Adsorption Method", PVC samples with dimensions of 20×20×1.0mm were completely buried in ceramic crucibles containing activated carbon powder. The ceramic crucibles were then placed in a forced-air drying oven at a temperature of 100±1℃. After 24 hours, the samples were removed and their mass loss was tested. The initial mass of the sample was recorded as W0. After the test, the sample was weighed again and recorded as W. Each test was performed in parallel three times to obtain the average value as the final loss rate. The volatile mass loss rate of the PVC sample was calculated using formula (1).

[0131] By observing the color change of material samples at 200℃ over time, the stability and aging rate of thermoplasticized polyester materials can be determined.

[0132] The test results are shown in Table 6.

[0133] Table 6

[0134]

[0135]

[0136] Table T d-50％ This indicates the thermal degradation temperature at which the polyester composition experiences a 50% mass loss.

[0137] As shown in Table 1, the polyester material plasticized with the bio-based lipid plasticizer of this invention exhibits higher tensile strength, elongation at break, volatility, and degradation temperature at 50% mass loss compared to the polyester plasticized with the comparative sample. This indicates that the polyester material plasticized with the bio-based lipid environmentally friendly plasticizer displays superior mechanical properties and better thermal stability and volatility resistance. This is because the bio-based lipid environmentally friendly plasticizer possesses long aliphatic chain structures, benzene ring structures, polyester group structures, and short ester branched chain structures. The nonpolar long alkyl chains insert into the polyester molecules, increasing the free volume and acting as a lubricant. The presence of the cyclic benzene ring structure improves the compatibility of the plasticizer with polyester molecules while increasing its thermal stability and mechanical properties. The multiple polar ester groups it contains form hydrogen bonds with the ester groups on the polyester molecules, offsetting some of the interaction forces between polyester molecules and increasing compatibility with polyester molecules. Furthermore, the short ester branched chain structure increases intermolecular interactions and physical interpenetration, significantly reducing the volatility of the plasticizer in the polyester molecular matrix.

[0138] In addition, thermogravimetric analysis was performed on five plasticizers: methyl oleate, plasticizer A (benzyl oleate), plasticizer B (acetoxy fatty acid methyl ester), plasticizer C (methyl acetooleate-benzoate), and the plasticizer of the present invention (acetyl oleate-salicylate). The results are as follows: Figure 2As shown, when the mass loss is 50%, the degradation temperature of plasticizer 1 is higher than that of other plasticizers.

[0139] The specific results are shown in Table 7.

[0140] Table 7

[0141] plasticizer <![CDATA[T d-50％ ]]> Plasticizer 1 376 Plasticizer 7 379 Plasticizer 8 383 Methyl oleate 262 Plasticizer A 274 Plasticizer B 272 Plasticizer C 364

[0142] Table T d-50％ This indicates the thermal degradation temperature at which the plasticizer mass loss is 50%.

[0143] This indicates that the synthesized acetylated fatty acid ester-salicylic acid ester has higher thermal stability because fatty acid esters contain only long fatty chain structures and have small molecular weights, resulting in the worst thermal stability. Benzyl oleate contains a benzene ring structure, an ester group, and a long chain structure, thus exhibiting relatively high thermal stability. Acetoxylated fatty acid methyl ester contains only a long fatty chain structure and an ester branch, and has a small molecular weight, resulting in poor thermal stability. Acetyloleate methyl ester-benzoate contains a benzene ring, two ester groups, a long fatty chain, and an ester branch, resulting in relatively high thermal stability. Actylated fatty acid ester-salicylic acid ester contains a benzene ring structure, a long fatty chain structure, multiple ester groups, and short ester branch structures, and its molecular weight is higher than other plasticizers, thus exhibiting the best thermal stability.

[0144] Observing the color change of plasticized polyester samples at 200℃ over time, PLA film I, PGA film I, PHA film I, PET film G, and PC film I turned black within 5 minutes, indicating poor thermal stability; PLA film K, PGA film K, PHA film K, PET film K, and PC film K turned black within 10 minutes, also indicating poor thermal stability; PLA film J / L, PGA film J / L, PHA film J / L, PET film J / L, and PC film J / L slowly turned black around 40 minutes; PLA film AH, PGA film AH, PHA film AH, PET film AH, and PC film AH only slowly turned black after 50 minutes, exhibiting good color retention and... Thermal aging performance: This is because bio-based lipid-based environmentally friendly plasticizers have long aliphatic chain structures, benzene ring structures, polyester group structures, and short ester branched chain structures. The non-polar long alkyl chains insert into polyester molecules to increase free volume and act as a lubricant. The presence of benzene ring structures improves the compatibility of plasticizers with polyester molecules while increasing their thermal stability and mechanical properties. The multiple polar ester groups they contain form hydrogen bonds with the ester groups on polyester molecules, which offset some of the interaction forces between polyester molecules, increasing compatibility with polyester molecules. In addition, the short ester branched chain structure increases the interaction and physical penetration between molecules. Therefore, bio-based lipid-based environmentally friendly plasticizers have the best color retention and thermal aging performance.

[0145] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A bio-based ester plasticizer modified polyester composition characterized in that, Its raw materials include 70-95 wt% polyester materials and 5-30 wt% bio-based ester plasticizers; The structure of the bio-based ester plasticizer is shown in formula A1, A2, or A3: ， In the formula, R1 is C 1-10 alkyl; n1 is the number of -CH2- on the fatty chain, which is 7 or 8; n2 is the number of substituents R2 on the benzene ring, which can be 1, 2, 3 or 4; Each R2 is independently selected from -OC 1-4 Alkyl, acetoxy, and at least one of them is selected from acetoxy; n3 represents the number of -CH2- atoms on the fatty chain, which can be 1, 2, 3, 4, 5, 6, 7, or 8. n4 represents the number of -CH2- atoms on the fatty chain, which can be 1, 2, 3, 4, 5, 6, 7, or 8. n5 represents the number of -CH2- atoms on the fatty acid chain, which can be 1, 2, 3, 4, 5, 6, 7, or 8.

2. The bio-based ester plasticizer modified polyester composition according to claim 1, characterized in that, The specific structure of the bio-based ester plasticizer is as follows: ， R1 is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, or decyl. At least one of R2, R3, R4, and R5 is selected from acetoxy, and the rest are hydrogen or methoxy.

3. The bio-based ester plasticizer modified polyester composition according to claim 1, wherein, The specific structure of the bio-based ester plasticizer is as follows: ， R1is C 1-10 alkyl; At least one of R2, R3, R4, and R5 is selected from acetoxy, and the rest are hydrogen or methoxy.

4. The bio-based ester plasticizer modified polyester composition according to claim 1, wherein, The preparation method of the bio-based ester plasticizer includes: firstly, preparing an epoxy fatty acid ester from fatty acid ester and catalyst 1 through an epoxidation reaction; then preparing a fatty acid ester from the epoxy fatty acid ester, natural organic acid, and ring-opening agent through a ring-opening reaction. Organic acid esters; finally, fatty acid esters. Organic acid esters, acetic anhydride, and catalyst 2 are used to acetylate bio-based ester plasticizers.

5. The bio-based ester plasticizer modified polyester composition according to claim 4, characterized in that, The fatty acid ester is at least one of methyl oleate, ethyl oleate, butyl oleate, hexyl oleate, octyl oleate, decyl oleate, methyl linoleate, ethyl linoleate, butyl linoleate, hexyl linoleate, octyl linoleate, decyl linoleate, methyl linolenic acid, ethyl linolenic acid, butyl linolenic acid, hexyl linolenic acid, octyl linolenic acid, and decyl linolenic acid; the natural organic acid is at least one of salicylic acid, vanillic acid, syringic acid, gentianic acid, protocatechuic acid, and gallic acid; the catalyst 1 is any one of m-chloroperoxybenzoic acid and hydrogen peroxide; the ring-opening agent is any one of tetrabutylammonium chloride and tetrabutylammonium bromide; the catalyst 2 is any one of a strong acid cation exchange resin and concentrated sulfuric acid.

6. The bio-based ester plasticizer-modified polyester composition according to claim 4, characterized in that, In the epoxidation reaction, the molar ratio of fatty acid ester to catalyst 1 is 1:1.2 to 3.2; In the ring-opening reaction, the molar ratio of epoxy fatty acid ester to natural organic acid is 1:1.4 to 4.5; the amount of ring-opening agent added is 0.1 wt% to 5 wt% of the mass of epoxy fatty acid ester.

7. The bio-based ester plasticizer modified polyester composition according to any one of claims 4-6, characterized in that, In the acetylation reaction, the amount of acetic anhydride added is equal to the amount of fatty acid ester. The organic esters account for 50% to 90%; the catalyst 2 is added at 5 wt% to 15 wt% of the fatty acid esters-organic esters.

8. The bio-based ester plasticizer-modified polyester composition according to claim 1, characterized in that, The polyester material is one or more of polylactic acid, polyglycolic acid, polyhydroxyalkanoate, polybutylene succinate, polyethylene terephthalate, polyethylene terephthalate, and polyethylene furanate.

9. A process for the preparation of the bio-based ester plasticizer modified polyester composition according to any one of claims 1 to 8, characterized in that, Includes the following steps: Polyester materials and bio-based ester plasticizers are added to a screw extruder or torque rheometer for melt blending, and then processed through a molding process to prepare plasticized polyester materials with excellent comprehensive performance.

10. The use of the bio-based ester plasticizer modified polyester composition according to any one of claims 1-8 in the fields of packaging, construction, automobiles, biopharmaceutical preparation, textiles or electronics.

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