High-performance precipitation-resistant PVC (polyvinyl chloride) composition as well as preparation method and application thereof

Abstract

The invention discloses a high-performance precipitation-resistant PVC (polyvinyl chloride) composition as well as a preparation method and application thereof, and belongs to the technical field of macromolecular processing aids. The PVC composition comprises 80-120 parts by weight of PVC pasty resin powder, 20-50 parts by weight of an oleate-based plasticizer and 1-20 parts by weight of a functional auxiliary agent, wherein the structure of the oleate-based plasticizer is shown in the specification. The plasticizer is applied to the PVC composition, the compatibility of the PVC composition is improved, the PVC composition has excellent processing performance, and the tensile strength, the elongation at break, the thermal stability and the migration resistance of the PVC composition are better than those of a PVC composition plasticized by an orthophthalic plasticizer.

Description

Technical Field

[0001] The invention relates to the technical field of polymer processing aids, and in particular to a high-performance precipitation-resistant PVC composition and a preparation method and application thereof. Background Art

[0002] Polyvinyl chloride (PVC) is a thermoplastic with excellent mechanical properties, good chemical corrosion resistance and low cost. Therefore, it has been widely used in pipelines, packaging, wiring, construction and cables. However, pure PVC material is hard and brittle. At the same time, at higher temperatures, PVC molecules will release chlorine atoms, resulting in poor thermal stability. Therefore, some plasticizers are often added to PVC products to reduce the glass transition temperature of PVC, making PVC more flexible without changing the basic chemical properties of the polymer, which is conducive to its application in more fields. In the past few decades, phthalate plasticizers have been used the most, but due to their low molecular weight, they are easy to migrate, resulting in the deterioration of the mechanical properties of the material, and may also pose some risks to human health. With the introduction of relevant policies, it is crucial to develop new green plasticizers that are non-toxic, highly compatible with resins, low in cost and strong in plasticizing ability to replace traditional petroleum-based plasticizers.

[0003] Methyl oleate is one of the derivatives of oils and fats. Since it can be used as automobile fuel, it has long become a research hotspot. However, only methyl oleate with a long alkyl chain is used as a plasticizer for PVC products. Due to its poor compatibility with PVC resin, it is easy to precipitate from PVC products and can only be added in small amounts as an auxiliary plasticizer. CN117986692A discloses a method for preparing an acetoxy fatty acid methyl ester environmentally friendly plasticizer. Refined diesel is sulfonated with sulfuric acid and then hydrolyzed to obtain a mixture containing hydroxy fatty acid methyl esters; then acetylated with acetic anhydride under the action of a catalyst to obtain a mixture containing acetoxy fatty acid methyl esters; after purification, the mixture is allowed to stand for stratification to obtain an upper oil layer; and the oil layer is washed to obtain the acetoxy fatty acid methyl ester environmentally friendly plasticizer. The plasticizer has not only high plasticizing efficiency, low volatility, good compatibility with PVC, but also excellent low-temperature softness. However, the thermal stability and mechanical properties of the PVC products plasticized by the plasticizer are poor.

[0004] CN110627643A discloses a method for preparing an environmentally friendly plasticizer using waste oil. The invention adopts higher fatty acids, methanol, 50% hydrogen peroxide, trimellitic anhydride and acetic anhydride purified from waste oil as main raw materials, and carries out molecular structure transformation and functional group conversion through four-step reactions of esterification, epoxidation, ring-opening esterification and acetylation to obtain an environmentally friendly plasticizer product, acetyl fatty acid methyl ester-trimellitic acid ester. The environmentally friendly plasticizer product prepared by the invention has the characteristics of a combination of cyclic molecules and linear molecules at the same time, the product has moderate viscosity, yellow color, good migration resistance and heat resistance, is suitable for industrial production, and is expected to replace traditional phthalate plasticizers. However, this type of plasticizer is a tribasic acid ester structure with a relatively large molecular weight, and the tribasic ester structure has a large steric hindrance, the obtained PVC product has strong rigidity, poor flexibility, and insufficient mechanical properties; and trimellitic anhydride is not a bio-based raw material, and the obtained plasticizer has a relatively large molecular weight and a relatively large viscosity. Summary of the invention

[0005]

Technical issues

[0006] The invention aims at the problems of poor compatibility, high volatility and insufficient mechanical properties of bio-based plasticizer plasticized PVC materials, and provides a high-performance precipitation-resistant PVC composition and a preparation method and application thereof. The fatty acid ester-based plasticizer with excellent performance is prepared by using fatty acid ester, natural organic acid and acetic anhydride as raw materials. The fatty acid ester-based plasticizer contains a long fatty chain structure, a benzene ring structure, a multi-ester structure and a short ester branched structure, and thus has special plasticizing properties.

[0007]

Technical solution

[0008] The present invention provides a high-performance precipitation-resistant PVC composition, which comprises 80-120 parts by weight of PVC paste resin powder, 20-50 parts by weight of fatty acid ester-based plasticizer and 1-20 parts by weight of functional additive;

[0009] The structure of the fatty acid ester-based plasticizer is shown in formula (A1), (A2), or (A3):

[0010]

[0011] In the formula, R 1 C 1-10 alkyl;

[0012] n1 is -CH on the fatty chain 2 - is 1, 2, 3, 4, 5, 6, 7 or 8;

[0013] n2 is a substituent R on the benzene ring 2 The number of substitutions is 1, 2, 3 or 4;

[0014] Each R2 are independently selected from -O-C1-4 alkyl, -O-CO-C 1-4 alkyl;

[0015] n3 is -CH on the fatty chain 2 - is 1, 2, 3, 4, 5, 6, 7 or 8;

[0016] n4 is -CH on the fatty chain 2 - is 1, 2, 3, 4, 5, 6, 7 or 8;

[0017] n5 is -CH on the fatty chain 2 - is 1, 2, 3, 4, 5, 6, 7 or 8;

[0018] In an embodiment of the present invention, there is at least one -O-CO-C 1-4 Alkyl substitution.

[0019] In an embodiment of the present invention, the structure of the fatty acid ester-based plasticizer may be:

[0020]

[0021] R 1 is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, decyl;

[0022] R 2 , R 3 , R 4 , R 5 Each of them is independently selected from methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, tert-butoxy, acetoxy, propionyloxy and butyryloxy; and the rest are hydrogen.

[0023] In an embodiment of the present invention, R 2 , R 3 , R 4 , R 5 At least one of them is selected from -O-CO-C 1-4 Alkyl substituted; the rest are arbitrarily selected from: hydrogen, -O-C1-4 alkyl, or -O-CO-C 1-4 Alkyl substitution.

[0024] In an embodiment of the present invention, further, R 2 , R 3 , R 4 , R 5 At least one of them is selected from acetoxy; the rest are hydrogen or methoxy.

[0025] In one embodiment of the present invention, the specific steps of the fatty acid ester-based plasticizer used are as follows: using fatty acid ester and catalyst 1 as raw materials to prepare epoxy fatty acid ester through epoxidation reaction; then preparing fatty acid ester-organic acid ester through ring-opening reaction using epoxy fatty acid ester, natural organic acid and ring-opening agent; finally, preparing the corresponding fatty acid ester-organic acid ester, acetic anhydride and catalyst 2 through acetylation reaction.

[0026] 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 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 linoleate, ethyl linoleate, butyl linoleate, hexyl linoleate, octyl linoleate, decyl linoleate, methyl linoleate, ethyl linoleate, butyl linoleate, hexyl linoleate, octyl linoleate and decyl linoleate.

[0027] In one embodiment of the present invention, the natural organic acid is any one of salicylic acid, vanillic acid, syringic acid, gentisic acid, protocatechuic acid and gallic acid.

[0028] In an embodiment of the present invention, the catalyst 1 is any one of meta-chloroperbenzoic acid and hydrogen peroxide.

[0029] In an embodiment of the present invention, the ring-opening agent is any one of tetrabutylammonium chloride and tetrabutylammonium bromide.

[0030] In an embodiment of the present invention, the catalyst 2 is any one of a strongly acidic cation exchange resin and concentrated sulfuric acid.

[0031] In one embodiment of the present invention, in the epoxidation reaction, the molar ratio of the fatty acid ester to the catalyst 1 is 1:1.2-3.2.

[0032] In one embodiment of the present invention, the epoxidation reaction specifically includes the following process: dissolving fatty acid ester and m-chloroperbenzoic acid in dichloromethane, reacting in an ice-water bath, and then reacting at room temperature, washing to neutrality after the reaction, purifying and drying to obtain the product epoxy fatty acid ester.

[0033] In one embodiment of the present invention, the specific steps of the epoxidation reaction are: adding an acidic ion exchange resin and formic acid to a fatty acid ester, and then dropping hydrogen peroxide to react to obtain an epoxy fatty acid ester.

[0034] 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 1:1.4-4.5.

[0035] Furthermore, if the fatty acid ester is a fatty acid ester containing one unsaturated double bond, the molar ratio of the epoxy fatty acid ester to the natural organic acid is 1:1.4-2.5; if the fatty acid ester is a fatty acid ester containing two unsaturated double bonds, the molar ratio of the epoxy fatty acid ester to the natural organic acid is 1:2.0-3.5; if the fatty acid ester is a fatty acid ester containing three unsaturated double bonds, the molar ratio of the epoxy fatty acid ester to the natural organic acid is 1:3.0-4.5.

[0036] In one embodiment of the present invention, in the ring-opening reaction, the amount of the ring-opening agent added is 0.1 wt%-5 wt% of the mass of the epoxy fatty acid ester, and can further be 4 wt%-5 wt%.

[0037] In one embodiment of the present invention, the ring-opening reaction specifically includes the following process: specifically includes the following process: mixing the epoxy fatty acid ester, natural organic acid and the ring-opening agent and heating them to 120-140°C, continuing the reaction for 4-7 hours, washing to neutrality after the reaction, purifying and drying to obtain the product fatty acid ester-organic acid ester.

[0038] In one embodiment of the present invention, in the acetylation reaction, the amount of acetic anhydride added is 50%-90% of the fatty acid ester-organic acid ester.

[0039] In one embodiment of the present invention, in the acetylation reaction, the added amount of the catalyst 2 is 5 wt % to 15 wt % of the fatty acid ester-organic acid ester.

[0040] The fatty acid ester-organic acid ester, acetic anhydride and catalyst are mixed and heated to 60° C.-90° C., and the reaction is continued for 18-24 hours. After the reaction is completed, the mixture is washed to neutrality, purified and dried to obtain the final product, the fatty acid ester-based plasticizer.

[0041] In one embodiment of the present invention, the functional additive used is one or more of a heat stabilizer, a lubricant, a filler, a modifier and an antioxidant.

[0042] In one embodiment of the present invention, the method for preparing the high-performance precipitation-resistant PVC composition comprises the following steps:

[0043] 80-120 parts by weight of PVC paste resin powder, 20-50 parts by weight of fatty acid ester-based plasticizer and 1-20 parts by weight of functional additives are added to a screw extruder or a torque rheometer for melt blending, and then a molding process is performed to prepare a PVC composition with excellent comprehensive performance.

[0044] In one embodiment of the present invention, the temperature of melt blending is 150-170° C. and the time is 5-10 min.

[0045] The present invention also provides the application of the high-performance precipitation-resistant PVC composition in the fields of packaging, construction, automobile, biomedicine preparation, agriculture or electronic appliances.

[0046]

Beneficial Effects

[0047] (1) The present invention prepares a plasticizer having a long fatty chain structure, a benzene ring structure, a polyester structure, and a short ester branched structure; the plasticizer is applied to a PVC composition to improve the compatibility of the PVC composition so that it has excellent processing performance, and the tensile strength, elongation at break, thermal stability, and migration resistance of the PVC composition are better than those of a PVC composition plasticized with an ortho-phthalic plasticizer.

[0048] (2) The non-polar long alkyl chain is inserted into PVC to increase the free volume and act as a lubricant. The presence of the cyclic benzene ring structure improves the compatibility of the plasticizer with PVC while increasing its thermal stability and mechanical properties. The multiple polar ester groups contained in it produce dipole-dipole interactions with the α-H on the polar PVC molecules, which offset part of the interaction force between PVC and increase the compatibility with PVC. The short ester branched structure increases the interaction and physical interpenetration between molecules, and the mobility of the plasticizer in the PVC matrix is ​​significantly reduced, which can replace traditional phthalate plasticizers.

[0049] (3) The raw materials used in the present invention are derived from bio-based materials, which are green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is the infrared spectrum of the plasticizer 1 acetyl oleate methyl ester-salicylate product;

[0051] Figure 2 The thermogravimetric curves of plasticizer 1 acetyl oleate methyl salicylate and comparative plasticizers; the comparative plasticizers include: methyl oleate, plasticizer A (benzyl oleate), plasticizer B (acetoxy fatty acid methyl ester) and plasticizer C (acetyl oleate methyl benzoate).

[0052] Figure 3 The color changes of PVC samples of different comparative examples and embodiments at 200°C over time. DETAILED DESCRIPTION

[0053] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0054] Preparation of a series of fatty acid ester-based plasticizers

[0055] Preparation of Plasticizer 1:

[0056] (R 1 =Me, R 2=-O-COCH 3 , R 3 =R 4 =R 5 =H)

[0057] (1) 37 g of m-chloroperbenzoic acid was dissolved in 150 mL of dichloromethane and stirred under ice-water bath conditions, and then 100 mL of dichloromethane solution containing 50 g of methyl oleate was added dropwise to the above system, and the above raw materials were first reacted in an ice-water bath for 0.5 h, and then reacted at room temperature for 24 h. After the reaction, the mixture was washed with sodium thiosulfate solution and sodium bicarbonate solution until neutral, and then washed with sodium chloride solution for 3 times, and finally washed with deionized water for 3 times, and then dichloromethane was removed by vacuum distillation at -0.1 MPa and 35° C. to obtain the product epoxy methyl oleate;

[0058] (2) adding 50 g (0.16 mol) of the product methyl oleate obtained in step (1), 33 g (0.24 mol) of salicylic acid and 2 g of tetrabutylammonium chloride into a reactor under a nitrogen atmosphere, mixing the above raw materials and heating them to 140° C., and continuing the reaction for 5 h. After the reaction is completed, washing with deionized water until neutral, and then vacuum distilling the organic phase under -0.1 MPa and 75° C. to remove water to obtain the product methyl oleate-salicylate;

[0059] (3) 50 g of the product of step (2), 35 g of acetic anhydride and 2.5 g of a strongly acidic cation exchange resin are added to a reactor, the raw materials are mixed and heated to 85° C., and the reaction is continued for 24 hours. After the reaction is completed, the acetic anhydride is first removed by vacuum distillation at -0.1 MPa and 120° C., and then washed with deionized water until neutral, and then vacuum distilled at -0.1 MPa and 75° C. to remove water to obtain the final product, oleate-based plasticizer methyl acetyl oleate-salicylate.

[0060] The infrared spectrum test of the product acetyloleate methyl salicylate in the preparation process was carried out, and the test results are as follows Figure 1 shown.

[0061] Figure 1 From top to bottom are epoxy oleic acid methyl ester, oleic acid methyl ester-salicylate and the final product acetyl oleic acid methyl ester-salicylate. In the first step of the epoxidation reaction, the infrared curve of epoxy oleic acid methyl ester at 928cm -1 The formation of epoxy bond (COC) proved the successful preparation of epoxy oleic acid methyl ester. Subsequently, the stretching vibration peak of epoxy bond (COC) in the infrared curve of methyl oleate-salicylate disappeared, and the peak at 3493 cm -1 The appearance of the stretching vibration peak of the hydroxyl group (-OH) at 3493 cm -1The stretching vibration peak of the hydroxyl group (-OH) disappeared, which proved that the acetylation reaction was successful and acetyl oleate methyl ester-salicylate was successfully synthesized.

[0062] Preparation of Plasticizer 2:

[0063] (R 1 =Me, R 3 =OMe, R 4 =-O-COCH 3 , R 2 =R 5 =H)

[0064] (1) 40 g of m-chloroperbenzoic acid was dissolved in 150 mL of dichloromethane and stirred under ice-water bath conditions, and then 100 mL of dichloromethane solution containing 50 g of methyl oleate was added dropwise to the above system, and the above raw materials were first reacted in an ice-water bath for 0.5 h, and then reacted at room temperature for 24 h. After the reaction, the mixture was washed with sodium thiosulfate solution and sodium bicarbonate solution until neutral, and then washed with sodium chloride solution for 3 times, and finally washed with deionized water for 3 times, and then dichloromethane was removed by vacuum distillation at -0.1 MPa and 35° C. to obtain the product epoxy methyl oleate;

[0065] (2) 50 g (0.16 mol) of the product methyl oleate obtained in step (1), 40 g (0.24 mol) of vanillic acid and 0.1 g of tetrabutylammonium chloride are added to a reactor under a nitrogen atmosphere, the above raw materials are mixed and heated to 140° C., and the reaction is continued for 5 hours. After the reaction is completed, the organic phase is washed with deionized water until neutral, and the organic phase is vacuum distilled under -0.1 MPa and 75° C. to remove water to obtain the product methyl oleate-vanillate;

[0066] (3) Add 50 g of the product of step (2) methyl oleate-vanillate, 25 g of acetic anhydride and 5 g of strongly acidic cation exchange resin into a reactor, mix the above raw materials, heat to 85° C., and continue the reaction for 24 hours. After the reaction is completed, first remove the acetic anhydride by vacuum distillation at -0.1 MPa and 120° C., then wash with deionized water to neutrality, and then vacuum distill to remove water at -0.1 MPa and 75° C. to obtain the final product, oleate-based environmentally friendly plasticizer acetyl oleate methyl vanillate.

[0067] Preparation of Plasticizer 3:

[0068] (R 1 =Et, R 3 =R 5 =OMe, R 4 =-O-COCH 3 , R 2 =H)

[0069] (1) 43 g of m-chloroperbenzoic acid was dissolved in 150 mL of dichloromethane and stirred under ice-water bath conditions, and then 100 mL of dichloromethane solution containing 50 g of ethyl oleate was added dropwise to the above system, and the above raw materials were first reacted in an ice-water bath for 0.5 h, and then reacted at room temperature for 24 h. After the reaction, the mixture was washed with sodium thiosulfate solution and sodium bicarbonate solution until neutral, and then washed with sodium chloride solution for 3 times, and finally washed with deionized water for 3 times, and then dichloromethane was removed by vacuum distillation at -0.1 MPa and 35° C. to obtain the product epoxy ethyl oleate;

[0070] (2) adding 50 g (0.16 mol) of the product ethyl oleate obtained in step (1), 48 g (0.24 mol) of syringic acid and 1 g of tetrabutylammonium chloride into a reactor under a nitrogen atmosphere, mixing the above raw materials and heating to 140° C., and continuing the reaction for 5 h. After the reaction is completed, washing with deionized water until neutral, and then vacuum distilling the organic phase under -0.1 MPa and 75° C. to remove water to obtain the product ethyl oleate-syringate;

[0071] (3) 50 g of the product of step (2) ethyl oleate-syringate, 40 g of acetic anhydride and 7.5 g of a strongly acidic cation exchange resin are added to a reactor, the raw materials are mixed and heated to 85° C., and the reaction is continued for 24 hours. After the reaction is completed, the acetic anhydride is first removed by vacuum distillation at -0.1 MPa and 120° C., and then washed with deionized water until neutral, and then vacuum distilled at -0.1 MPa and 75° C. to remove water to obtain the final product, oleate-based environmentally friendly plasticizer ethyl acetyl oleate-syringate.

[0072] Preparation of Plasticizer 4:

[0073] (R 1 = n-butyl, R 2 =R 5 =-O-COCH 3 , R 3 =R 4 =H)

[0074] (1) 37 g of m-chloroperbenzoic acid was dissolved in 150 mL of dichloromethane and stirred under ice-water bath conditions, and then 100 mL of dichloromethane solution containing 50 g of butyl oleate was added dropwise to the above system, and the above raw materials were first reacted in an ice-water bath for 0.5 h, and then reacted at room temperature for 24 h. After the reaction, the mixture was washed with sodium thiosulfate solution and sodium bicarbonate solution until neutral, and then washed with sodium chloride solution for 3 times, and finally washed with deionized water for 3 times, and then dichloromethane was removed by vacuum distillation at -0.1 MPa and 35° C. to obtain the product epoxy butyl oleate;

[0075] (2) adding 50 g (0.14 mol) of the product butyl oleate obtained in step (1), 32.3 g (0.21 mol) of gentisic acid and 2.5 g of tetrabutylammonium chloride into a reactor under a nitrogen atmosphere, mixing the above raw materials and heating them to 140° C., and continuing the reaction for 5 h. After the reaction is completed, washing with deionized water until neutral, and then vacuum distilling the organic phase at -0.1 MPa and 75° C. to remove water to obtain the product butyl oleate-gentisate;

[0076] (3) 50 g of the product of step (2), 35 g of acetic anhydride and 7.5 g of a strongly acidic cation exchange resin are added to a reactor, the raw materials are mixed and heated to 85° C., and the reaction is continued for 24 hours. After the reaction is completed, the acetic anhydride is first removed by vacuum distillation at -0.1 MPa and 120° C., and then washed with deionized water until neutral, and then vacuum distilled at -0.1 MPa and 75° C. to remove water to obtain the final product, oleate-based environmentally friendly plasticizer acetyl butyl oleate-gentisate.

[0077] Preparation of Plasticizer 5:

[0078] (R 1 = hexyl, R 3 =R 4 =-O-COCH 3 , R 2 =R 5 =H)

[0079] (1) 37 g of m-chloroperbenzoic acid was dissolved in 150 mL of dichloromethane and stirred under ice-water bath conditions, and then 100 mL of dichloromethane solution containing 50 g of hexyl oleate was added dropwise to the above system, and the above raw materials were first reacted in an ice-water bath for 0.5 h, and then reacted at room temperature for 24 h. After the reaction, the mixture was washed with sodium thiosulfate solution and sodium bicarbonate solution until neutral, and then washed with sodium chloride solution for 3 times, and finally washed with deionized water for 3 times, and then dichloromethane was removed by vacuum distillation at -0.1 MPa and 35° C. to obtain the product epoxy hexyl oleate;

[0080] (2) 50 g (0.13 mol) of the product epoxidized hexyl oleate obtained in step (1), 29.2 g (0.19 mol) of protocatechuic acid and 2 g of tetrabutylammonium chloride were added to a reactor under a nitrogen atmosphere, the raw materials were mixed and heated to 140° C., and the reaction was continued for 5 h. After the reaction was completed, the organic phase was washed with deionized water until neutral, and the organic phase was vacuum distilled under -0.1 MPa and 75° C. to remove water to obtain the product hexyl oleate-protocatechuate;

[0081] (3) Add 50 g of the product of step (2) hexyl oleate-protocatechuate, 35 g of acetic anhydride and 5 g of strongly acidic cation exchange resin into a reactor, mix the above raw materials, heat to 85° C., and continue the reaction for 24 hours. After the reaction is completed, first remove the acetic anhydride by vacuum distillation at -0.1 MPa and 120° C., then wash with deionized water to neutrality, and then remove water by vacuum distillation at -0.1 MPa and 75° C. to obtain the final product, oleate-based environmentally friendly plasticizer hexyl oleate-protocatechuate.

[0082] Preparation of plasticizer 6:

[0083] (R 1 =Decyl, R 2 =H, R 3 =R 4 =R 5 =-O-COCH 3 )

[0084] (1) Add 0.5 g of formic acid and 0.05 g of acidic ion exchange resin to 50 g of decyl oleate, and drip 35% hydrogen peroxide at 60-75° C. while stirring. The dripping is completed within 4 hours, and then reacted for 1 hour. After the reaction is completed, cool to below 50° C., wash with sodium carbonate solution and deionized water until neutral, and then vacuum distill at -0.1 MPa and 100° C. to remove impurities to obtain the product decyl epoxy oleate;

[0085] (2) adding 50 g (0.11 mol) of the product epoxy oleate obtained in step (1), 30.6 g (0.18 mol) of gallic acid and 2 g of tetrabutylammonium chloride into a reactor under a nitrogen atmosphere, mixing the above raw materials and heating them to 140° C., and continuing the reaction for 5 h. After the reaction is completed, washing with deionized water until neutral, and then vacuum distilling the organic phase at -0.1 MPa and 75° C. to remove water to obtain the product oleate decyl gallate;

[0086] (3) Add 50 g of the product of step (2), 35 g of acetic anhydride and 5 g of a strongly acidic cation exchange resin into a reactor, mix the above raw materials, heat to 85° C., and continue the reaction for 24 hours. After the reaction is completed, the acetic anhydride is first removed by vacuum distillation at -0.1 MPa and 120° C., then washed with deionized water until neutral, and then vacuum distilled at -0.1 MPa and 75° C. to remove water to obtain the final product, oleate-based environmentally friendly plasticizer acetyl oleate decyl gallate.

[0087] Preparation of Plasticizer 7:

[0088] (R 1 =Me, R 3 =R 4=-O-COCH 3 , R 2 =R 5 =H)

[0089] (1) 80 g of m-chloroperbenzoic acid was dissolved in 150 mL of dichloromethane and stirred under ice-water bath conditions, and then 100 mL of dichloromethane solution containing 50 g of methyl linoleate was added dropwise to the above system, and the above raw materials were first reacted in an ice-water bath for 0.5 h, and then reacted at room temperature for 24 h. After the reaction, the mixture was washed with sodium thiosulfate solution and sodium bicarbonate solution until neutral, and then washed with sodium chloride solution for 3 times, and finally washed with deionized water for 3 times, and then dichloromethane was removed by vacuum distillation at -0.1 MPa and 35° C. to obtain the product methyl epoxylinoleate;

[0090] (2) 50 g (0.16 mol) of the product methyl epoxylinoleate obtained in step (1), 52.36 g (0.34 mol) of protocatechuic acid and 2 g of tetrabutylammonium chloride were added to a reactor under a nitrogen atmosphere, the above raw materials were mixed and heated to 140° C., and the reaction was continued for 5 hours. After the reaction was completed, the organic phase was washed with deionized water until neutral, and the organic phase was vacuum distilled under -0.1 MPa and 75° C. to remove water to obtain the product methyl linoleate-protocatechuate;

[0091] (3) Add 50 g of the product of step (2) methyl linoleate-protocatechuate, 40 g of acetic anhydride and 5 g of strongly acidic cation exchange resin into a reactor, mix the above raw materials, heat to 85° C., and continue the reaction for 24 hours. After the reaction is completed, first remove the acetic anhydride by vacuum distillation at -0.1 MPa and 120° C., then wash with deionized water to neutrality, and then remove water by vacuum distillation at -0.1 MPa and 75° C. to obtain the final product, fatty acid ester-based environmentally friendly plasticizer methyl acetyllinoleate-protocatechuate.

[0092] Preparation of plasticizer 8:

[0093] (R 1 =Me, R 2 =H, R 3 =R 4 =R 5 =-O-COCH 3 )

[0094] (1) 120 g of m-chloroperbenzoic acid was dissolved in 150 mL of dichloromethane and stirred under ice-water bath conditions, and then 100 mL of dichloromethane solution containing 50 g of methyl linolenate was added dropwise to the above system, and the above raw materials were first reacted in an ice-water bath for 0.5 h, and then reacted at room temperature for 24 h. After the reaction, the mixture was washed with sodium thiosulfate solution and sodium bicarbonate solution until neutral, and then washed with sodium chloride solution for 3 times, and finally washed with deionized water for 3 times, and then dichloromethane was removed by vacuum distillation at -0.1 MPa and 35° C. to obtain the product methyl epoxylinolenate;

[0095] (2) 50 g (0.16 mol) of the product methyl epoxylinolenate obtained in step (1), 85 g (0.50 mol) of gallic acid and 1 g of tetrabutylammonium chloride are added to a reactor under a nitrogen atmosphere, the above raw materials are mixed and heated to 140° C., and the reaction is continued for 5 hours. After the reaction is completed, the organic phase is washed with deionized water until neutral, and the organic phase is vacuum distilled under -0.1 MPa and 75° C. to remove water to obtain the product methyl linolenate-gallate;

[0096] (3) Add 50 g of the product of step (2), 45 g of acetic anhydride and 5 g of a strongly acidic cation exchange resin into a reactor, mix the above raw materials, heat to 85° C., and continue the reaction for 24 hours. After the reaction is completed, first remove the acetic anhydride by vacuum distillation at -0.1 MPa and 120° C., then wash with deionized water to neutrality, and then remove water by vacuum distillation at -0.1 MPa and 75° C. to obtain the final product, fatty acid ester-based environmentally friendly plasticizer methyl acetyl linolenate-gallate.

[0097] Preparation of PVC compositions

[0098] Example 1

[0099] 100 parts of PVC paste resin powder, 30 parts of plasticizer 1 (methyl acetyl oleate-salicylate), and 3 parts of liquid calcium-zinc composite stabilizer were fully dried and added into a torque rheometer according to weight ratio at 165° C. for melt blending for 6 minutes, and then a PVC composition was prepared through a molding process.

[0100] Example 2

[0101] 100 parts of PVC paste resin powder, 30 parts of plasticizer 2, and 3 parts of liquid calcium-zinc composite stabilizer were fully dried and added into a torque rheometer according to weight ratio at 165° C. for melt blending for 6 minutes, and then a PVC composition was prepared through a molding process.

[0102] Example 3

[0103] 100 parts of PVC paste resin powder, 30 parts of plasticizer 3, and 3 parts of liquid calcium-zinc composite stabilizer were fully dried and mixed by weight in a torque rheometer at 165° C. for 6 minutes, and then a PVC composition was prepared through a molding process.

[0104] Example 4

[0105] 100 parts of PVC paste resin powder, 30 parts of plasticizer 4, and 3 parts of liquid calcium-zinc composite stabilizer were fully dried and mixed by weight in a torque rheometer at 165° C. for 6 minutes, and then a PVC composition was prepared through a molding process.

[0106] Example 5

[0107] 100 parts of PVC paste resin powder, 30 parts of plasticizer 5, and 3 parts of liquid calcium-zinc composite stabilizer were fully dried and mixed by weight in a torque rheometer at 165° C. for 6 minutes, and then a PVC composition was prepared through a molding process.

[0108] Example 6

[0109] 100 parts of PVC paste resin powder, 30 parts of plasticizer 6, and 3 parts of liquid calcium-zinc composite stabilizer were fully dried and mixed by weight in a torque rheometer at 165° C. for 6 minutes, and then a PVC composition was prepared through a molding process.

[0110] Example 7

[0111] 100 parts of PVC paste resin powder, 30 parts of plasticizer 7, and 3 parts of liquid calcium-zinc composite stabilizer were fully dried and mixed by weight in a torque rheometer at 165° C. for 6 minutes, and then a PVC composition was prepared through a molding process.

[0112] Example 8

[0113] 100 parts of PVC paste resin powder, 30 parts of plasticizer 8, and 3 parts of liquid calcium-zinc composite stabilizer were fully dried and mixed by weight in a torque rheometer at 165° C. for melt blending for 6 minutes, and then a PVC composition was prepared through a molding process.

[0114] Example 9

[0115] The same as Example 1, except that 40 parts of acetyl oleate methyl salicylate were added, and the other parts remained unchanged, to obtain a PVC composition.

[0116] Example 10

[0117] The same as Example 1, except that 50 parts of acetyl oleate methyl salicylate were added, and the other parts remained unchanged, to obtain a PVC composition.

[0118] Comparative Example 1

[0119] The same as Example 1, except that no plasticizer is added, and other aspects remain unchanged to obtain a PVC composition.

[0120] Comparative Example 2

[0121] The same as Example 1, except that 30 parts of acetyl oleate methyl ester-salicylate are replaced by 30 parts of oleate methyl ester, and the rest remain unchanged, to obtain a PVC composition.

[0122] Comparative Example 3

[0123] The same as Example 7, except that 40 parts of acetyl oleic acid methyl ester-salicylate are replaced by 40 parts of methyl oleate, and the rest remain unchanged, to obtain a PVC composition.

[0124] Comparative Example 4

[0125] The same as Example 8, except that 50 parts of acetyl oleate methyl ester-salicylate are replaced by 50 parts of oleate methyl ester, and the rest remain unchanged, to obtain a PVC composition.

[0126] Comparative Example 5

[0127] The same as Example 1, except that 30 parts of acetyl oleic acid methyl ester-salicylate are replaced by 30 parts of plasticizer A, and the rest remain unchanged to obtain a PVC composition; wherein plasticizer A represents benzyl oleate, which can be prepared by the following method: 50 g of oleic acid, 18.8 g of benzyl alcohol, 0.85 g of p-toluenesulfonic acid and 13.5 g of toluene are reacted under a nitrogen environment at 130° C. for 10-12 h. After the reaction is completed, NaHCO 3 solution and deionized water to wash the crude product; finally, the crude product is distilled under reduced pressure to fully remove residual water and solvent in the crude product to obtain benzyl oleate.

[0128] Comparative Example 6

[0129] The same as Example 1, except that 30 parts of acetyl oleate methyl ester-salicylate are replaced by 30 parts of plasticizer B, and the other parts remain unchanged, to obtain a PVC composition; wherein, plasticizer B represents the acetoxy fatty acid methyl ester mentioned in the existing document CN117986692A (Example 6 in the document).

[0130] Comparative Example 7

[0131] The same as Example 1, except that 30 parts of acetyl oleic acid methyl ester-salicylate are replaced by 30 parts of plasticizer C, and the rest remain unchanged, to obtain a PVC composition; wherein, plasticizer C is prepared according to the preparation method of reference plasticizer 1, except that salicylic acid is replaced by benzoic acid to obtain acetyl oleic acid methyl ester-benzoate.

[0132] N 2 Thermogravimetric analysis of the plasticizer and PVC composition was carried out with 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.

[0133] The mechanical properties of the materials were tested according to GB / T 1040-2006, the tensile rate was 50 mm / min, and five samples were tested in parallel in each group.

[0134] According to GB / T9349-2002 Polyvinyl chloride, related chlorine-containing homopolymers and copolymers and their blends - Determination of thermal stability - Color change method, observe and record the color change of the sample. By observing the color change of PVC samples at 200°C over time, the stability and aging speed of thermal PVC products can be judged.

[0135] According to the standard "ISO 176-2005 activated carbon adsorption method", PVC samples with a size of 20×20×1.0mm were completely buried in ceramic crucibles filled with activated carbon powder, and then the ceramic crucibles were placed in a forced air hot oven at a temperature of 100±1℃. After 24 hours, the samples were taken out to test their mass loss. The initial mass of the sample was weighed, recorded as W0; at the end of the test, the sample was weighed, recorded as W. Each group of tests was performed three times in parallel to obtain the average value as the final loss rate result. The volatile mass loss rate of the PVC sample was calculated by formula (1),

[0136] Test example:

[0137] Table 1 Performance test of plasticized PVC of embodiments and comparative examples.

[0138] Table 1

[0139]

[0140]

[0141] Table T d-50％ It indicates the thermal degradation temperature corresponding to 50% mass loss of plasticized PVC film.

[0142] The “ / ” in the table indicates that pure PVC without adding plasticizer is non-volatile.

[0143] As can be seen from the data in Table 1, by Examples 1-8 and Comparative Examples 1-7, it can be seen that the tensile strength, elongation at break (plasticizing efficiency) and volatility resistance of the PVC materials of Examples 1-8 prepared in the present invention under the same mass fraction are far better than those of the comparative samples. When the mass loss is 50%, the degradation temperature corresponding to the plasticized PVC of Examples 1-8 is higher than that of the comparative sample, indicating that the PVC samples plasticized by the fatty acid ester-based environmentally friendly plasticizer show better thermal stability. This is because the fatty acid ester-based environmentally friendly plasticizer has a long fatty chain structure, a benzene ring structure, a multi-ester structure and a short ester branched structure, and the non-polar long alkyl chain is inserted into the PVC to increase the free volume and play a lubricating role. The presence of the cyclic structure increases the compatibility of the plasticizer with PVC while increasing its thermal stability and mechanical properties, and the multiple polar ester groups contained produce dipole-dipole interactions with the α-H on the polar PVC molecules to offset the interaction force between a part of PVC, increase the compatibility with PVC, and the short ester branched structure increases the interaction and physical interpenetration between molecules, and the volatility of the plasticizer in the PVC matrix is ​​significantly reduced.

[0144] Thermogravimetric analysis was performed on five plasticizers: methyl oleate, plasticizer A, plasticizer B, plasticizer C, and plasticizer 1 (acetyl oleate formate-salicylate). The results are as follows: Figure 2 As shown in Table 2, when the mass loss is 50%, the degradation temperature of plasticizer 1 is higher than that of other plasticizers.

[0145] Table 2

[0146] Plasticizers <![CDATA[T d-50％ <!-- 12 -->]]> Plasticizer 1 376 Plasticizer 7 379 Plasticizer 8 383 Methyl oleate 262 Plasticizer A 274 Plasticizer B 272 Plasticizer C 364

[0147] Observe the color change of PVC samples at 200°C over time. Comparative Example 1 has turned black within 10 minutes, and a large number of small bubbles are generated on the surface, indicating that the thermal stability of pure PVC material is very poor and hydrogen chloride will be released during heating; Comparative Example 2 also begins to turn black within 10 minutes, and a small number of small bubbles are generated on the surface, and its thermal stability is very poor; Comparative Example 5 turns black after 30 minutes without small bubbles on the surface; Comparative Example 6 slowly turns black in about 20 minutes and a small number of small bubbles are generated on the surface; Comparative Example 7 slowly turns yellow after 30 minutes, and turns black brown after 40 minutes without small bubbles on the surface; Example 1 does not turn black until 50 minutes after the surface without small bubbles, and has the best Good color retention and heat aging performance; this is because oleate-based environmentally friendly plasticizers have a long fatty chain structure, a benzene ring structure, a multi-ester structure and a short ester branched structure. The non-polar long alkyl chain is inserted into PVC to increase the free volume and act as a lubricant. The presence of the ring structure improves the compatibility of the plasticizer with PVC while increasing its thermal stability and mechanical properties. The multiple polar ester groups contained in it produce dipole-dipole interactions with the α-H on the polar PVC molecules, which offset part of the interaction force between PVC, increase compatibility with PVC, and the short ester branched structure increases the interaction and physical interpenetration between molecules. Therefore, methyl oleate-based environmentally friendly plasticizers have the best color retention and heat aging performance.

[0148] The embodiments provided above are not intended to limit the scope of the present invention, and the steps described are not intended to limit the execution order thereof. Those skilled in the art may make obvious improvements to the present invention in combination with existing common knowledge, which also fall within the scope of protection defined by the claims of the present invention.

Claims

1. A high-performance precipitation-resistant PVC composition, characterized in that: The composition comprises 80-120 parts by weight of PVC paste resin powder, 20-50 parts by weight of fatty acid ester-based plasticizer and 1-20 parts by weight of functional additive; The structure of the oleate-based plasticizer is shown in formula (A1), (A2), or (A3): In the formula, R1 is C 1-10 alkyl; n1 is the number of -CH2- groups on the aliphatic chain, which is 1, 2, 3, 4, 5, 6, 7 or 8; n2 is the number of substituents R2 on the benzene ring, which is 1, 2, 3 or 4; Each R2 is independently selected from -O-C1-4 alkyl, -OCO-C 1-4 alkyl; n3 is the number of -CH2- groups on the aliphatic chain, which is 1, 2, 3, 4, 5, 6, 7 or 8; n4 is the number of -CH2- groups on the aliphatic chain, which is 1, 2, 3, 4, 5, 6, 7 or 8; n5 is the number of -CH2- on the aliphatic chain, which is 1, 2, 3, 4, 5, 6, 7 or 8.

2. The medium-high performance precipitation-resistant PVC composition according to claim 1, characterized in that: The structure of the fatty acid ester-based plasticizer is specifically: R1 is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, decyl; R2, R3, R4, and R5 are independently selected from methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, tert-butoxy, acetoxy, propionyloxy, and butyryloxy; and the rest are hydrogen.

3. The medium-high performance precipitation-resistant PVC composition according to claim 1, characterized in that: The structure of the fatty acid ester-based plasticizer is specifically: R1 is C 1-10 alkyl; At least one of R2, R3, R4 and R5 is selected from acetoxy, and the others are hydrogen or methoxy.

4. The medium-high performance precipitation-resistant PVC composition according to claim 1, characterized in that: The specific steps of the fatty acid ester-based plasticizer used are as follows: using fatty acid ester and catalyst 1 as raw materials to prepare epoxy fatty acid ester through epoxidation reaction; then preparing fatty acid ester-organic acid ester through ring-opening reaction of epoxy fatty acid ester, natural organic acid and ring-opening agent; finally preparing the corresponding fatty acid ester-organic acid ester, acetic anhydride and catalyst 2 through acetylation reaction.

5. The medium-high performance precipitation-resistant PVC 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 linoleate, ethyl linoleate, butyl linoleate, hexyl linoleate, octyl linoleate, and decyl linoleate; the natural organic acid is any one of salicylic acid, vanillic acid, syringic acid, gentisic acid, protocatechuic acid, and gallic acid; the catalyst 1 is any one of meta-chloroperbenzoic acid and hydrogen peroxide; the ring-opening agent is any one of tetrabutylammonium chloride and tetrabutylammonium bromide; and the catalyst 2 is any one of a strongly acidic cation exchange resin and concentrated sulfuric acid.

6. The medium-high performance precipitation-resistant PVC composition according to claim 4, characterized in that: In the epoxidation reaction, the molar ratio of fatty acid ester to catalyst 1 is 1:1.2-3.2; In the ring-opening reaction, the molar ratio of the epoxy fatty acid ester to the natural organic acid is 1:1.4-4.5, and the added amount of the ring-opening agent is 0.1wt%-5wt% of the mass of the epoxy fatty acid ester.

7. The high-performance precipitation-resistant PVC composition according to any one of claims 4 to 6, characterized in that: In the acetylation reaction, the amount of acetic anhydride added is 50%-90% of the fatty acid ester-organic acid ester, and the amount of catalyst 2 added is 5wt%-15wt% of the fatty acid ester-organic acid ester.

8. The high-performance precipitation-resistant PVC composition according to claim 1, characterized in that: The functional additives used are one or more of a heat stabilizer, a lubricant, a filler, a modifier and an antioxidant.

9. A method for preparing a high-performance precipitation-resistant PVC composition according to any one of claims 1 to 8, characterized in that: The steps include: 80-120 parts by weight of PVC paste resin powder, 20-50 parts by weight of fatty acid ester-based plasticizer and 1-20 parts by weight of functional additives are added to a screw extruder or a torque rheometer for melt blending, and then a molding process is performed to prepare a PVC composition with excellent comprehensive performance.

10. Use of the high-performance precipitation-resistant PVC composition according to any one of claims 1 to 8 in the fields of packaging, construction, automobiles, medical equipment, agriculture or electronic appliances.

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