Epoxy plasticizer, its preparation method and application

Abstract

The application discloses an epoxy plasticizer and a preparation method and application thereof. The preparation method comprises the following steps: 1-1), mixing reactants and water-carrying agents and continuously feeding nitrogen under liquid surface, and heating to 125-128 DEG C; the reactants comprise sorbic acid, C4-C8 monocarboxylic acid and glycerol, and the molar ratio of the three is 0.27-0.77:2.25-2.75:1; 1-2), after heating to 130-140 DEG C, a catalyst is added, heating to 150-190 DEG C, and constant temperature reaction is carried out for 8-10 h; unsaturated sorbic acid glycerol mixed ester is obtained by reaction; the catalyst is 0.1-3% of the total mass of the reactants; 2-1), mixing the unsaturated sorbic acid glycerol mixed ester and phosphoric acid, reaction is carried out for 4-8 h at 50-70 DEG C, and the reaction is ended; the mixture of formic acid and hydrogen peroxide is dropped in 30-60 min after the reaction is started; the mass percentage of the phosphoric acid and the unsaturated sorbic acid glycerol mixed ester is 0.5-2wt%:1; the molar amount of the formic acid is 0.3-1.0 times of the molar amount of carbon-carbon double bond, and the molar amount of the hydrogen peroxide is 1.1-2.5 times of the molar amount of carbon-carbon double bond; 2-2), epoxy sorbic acid glycerol mixed ester is obtained after the reaction is ended.

Description

Technical Field

[0001] This disclosure relates to the field of additives for plastic products, and in particular to an epoxy plasticizer, its preparation method, and its application. Background Technology

[0002] Plasticizers are essential fine chemical additives in the production of plastics, and are among the world's largest producers and consumers of plastic additives. Because plasticizers have the advantages of lowering the glass transition temperature of polymers and improving their plasticity, they are widely used in plastic and rubber products, medical materials, building materials, and other fields.

[0003] Common plasticizers include di(2-ethylhexyl) phthalate (DEHP), dioctyl terephthalate (DOTP), and tributyl acetylacetonate (ATBC), among others. However, these plasticizers also have different drawbacks. For example, DEHP has widely recognized reproductive toxicity; DOTP has high hardness and poor elongation at break; and ATBC-plasticized PVC sheets are prone to migration and have poor thermal stability. Therefore, developing new, non-toxic plasticizers with excellent plasticizing properties is an urgent problem to be solved in the plasticizer industry. Summary of the Invention

[0004] This disclosure provides an epoxy plasticizer, its preparation method, and its application, to at least solve one of the technical problems existing in the prior art.

[0005] According to a first aspect of this disclosure, a method for preparing an epoxy plasticizer is provided, comprising:

[0006] Step 1): Esterification reaction: including,

[0007] Step 1-1): Mix the reactants with an appropriate amount of dehydrating agent and continuously purge nitrogen gas under the liquid surface, gradually raising the temperature to 125-128°C to dissolve the reactants; wherein the reactants include sorbic acid, C4-C8 monocarboxylic acid and glycerol, and the molar ratio of sorbic acid, C4-C8 monocarboxylic acid and glycerol is 0.27-0.77:2.25-2.75:1;

[0008] Steps 1-2): Gradually raise the temperature to 130-140℃, add the catalyst, and then continue to raise the temperature to 150-190℃ and react at a constant temperature for 8-10 hours; after the reaction is completed, wash with water until neutral, and then distill under reduced pressure to obtain unsaturated sorbic acid glycerol mixture; wherein, the catalyst is 0.1-3% of the total mass of the reactants;

[0009] Step 2): Epoxidation reaction: including,

[0010] Step 2-1): Mix the unsaturated sorbic acid glycerol mixture obtained in Step 1-2) with phosphoric acid, and react at 50-70°C for 4-8 hours. Simultaneously, add a mixture of formic acid and hydrogen peroxide dropwise within 30-60 minutes of the start of the reaction. The mass ratio of phosphoric acid to unsaturated sorbic acid glycerol mixture is 0.5-2 wt%:1. The molar amount of formic acid is 0.3-1.0 times the molar amount of carbon-carbon double bonds in the unsaturated sorbic acid glycerol mixture, and the molar amount of hydrogen peroxide is 1.1-2.5 times the molar amount of carbon-carbon double bonds in the unsaturated sorbic acid glycerol mixture.

[0011] Step 2-2): After the reaction is complete, the product is washed with water until neutral, then distilled under reduced pressure and dried to obtain a mixture of epoxy sorbic acid glycerol esters.

[0012] In one embodiment, in step 1-1), the C4-C8 monocarboxylic acid includes one or more straight-chain acids such as butyric acid, valeric acid, hexanoic acid, heptanoic acid, and octanoic acid.

[0013] In one possible implementation, in step 1-1),

[0014] The molar ratio of sorbic acid:C4-C8 straight-chain acid:glycerol is 0.77:2.25:1, or...

[0015] The molar ratio of sorbic acid:C4-C8 straight-chain acid:glycerol is 0.52:2.5:1, or...

[0016] The molar ratio of sorbic acid:C4-C8 straight-chain acid:glycerol is 0.27:2.75:1.

[0017] In one embodiment, the dehydrating agent is cyclohexane.

[0018] In one embodiment, during step 1), the esterification reaction is stirred at a speed of 400–800 r / min.

[0019] In one embodiment, the esterification reaction in step 1) is carried out in a flask equipped with a water separator, into which an appropriate amount of water-removing agent is added.

[0020] In one embodiment, in steps 1-2), the catalyst is one of tetrabutyl titanate, a strong acid cation exchange resin, p-toluenesulfonic acid, and a solid superacid.

[0021] According to a second aspect of this disclosure, an epoxy plasticizer is provided, which is prepared by the preparation method in any of the embodiments of the first aspect described above.

[0022] According to a third aspect of this disclosure, the use of the epoxy plasticizer in the preparation of plastics is provided.

[0023] In one embodiment, the plastic includes PLA and PVC.

[0024] Compared with the prior art, the advantages of this application are as follows: 1) The polyvinyl chloride plasticized by the plasticizer of this application has excellent tensile properties, which are superior to those of polyvinyl chloride plasticized by commonly used DEHP, DOTP and ATBC; 2) The polyvinyl chloride plasticized by the plasticizer of this application has good tensile strength and good elongation at break, and its comprehensive mechanical properties are superior to those of polyvinyl chloride plasticized by commonly used DEHP, DOTP and ATBC; 3) The thermal stability of the polyvinyl chloride prepared by the plasticizer of this application is comparable to that of DOTP, which currently has good thermal stability, and is superior to DEHP / PVC and ATBC / PVC; 4) The plasticizer of this application is derived from bio-based materials and has the advantages of being non-toxic and environmentally friendly.

[0025] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this disclosure, nor is it intended to limit the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0026] The above and other objects, features, and advantages of this disclosure will become readily apparent from the following detailed description of exemplary embodiments, taken in conjunction with the accompanying drawings. Several embodiments of this disclosure are illustrated in the drawings by way of example and not limitation, in which:

[0027] In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.

[0028] Figure 1 The infrared spectrum of the plasticizer prepared in Example 1 of this disclosure is shown.

[0029] Figure 2 The tensile stress-strain curves of PVC specimens according to embodiments of this disclosure are shown.

[0030] Figure 3 The results of thermal stability tests on PVC specimens according to embodiments of this disclosure are shown.

[0031] Figure 4 The results of thermal aging of PVC test pieces according to embodiments of this disclosure are shown;

[0032] Figure 5 The migration resistance results of PVC specimens according to embodiments of the present disclosure in water are shown;

[0033] Figure 6 The migration resistance results of PVC specimens according to embodiments of the present disclosure in n-hexane are shown. Detailed Implementation

[0034] To make the objectives, features, and advantages of this disclosure more apparent and understandable, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0035] In a first aspect, this disclosure provides a method for preparing an epoxy plasticizer, comprising:

[0036] Step 1): Esterification reaction: including,

[0037] Step 1-1): Mix the reactants and an appropriate amount of dehydrating agent, and continuously introduce nitrogen gas below the surface of the liquid (below the surface of the liquid after the reactants and dehydrating agent are mixed), gradually raising the temperature to 125-128℃ to dissolve the reactants; wherein the reactants include sorbic acid, C4-C8 monocarboxylic acid and glycerol, and the molar ratio of sorbic acid, C4-C8 monocarboxylic acid and glycerol is 0.27-0.77:2.25-2.75:1;

[0038] Steps 1-2): Gradually raise the temperature to 130-140℃, add the catalyst, and then continue to raise the temperature to 150-190℃ and react at a constant temperature for 8-10 hours; after the reaction is completed, wash with water until neutral, and then distill under reduced pressure to obtain unsaturated sorbic acid glycerol mixed esters; wherein, the catalyst is 0.1-3% of the total mass of the reactants; wherein, the purpose of continuously purging nitrogen gas is to remove O2, and nitrogen gas is continuously purged throughout the esterification reaction until the esterification reaction is completed;

[0039] Step 2): Epoxidation reaction: including,

[0040] Step 2-1): Mix the unsaturated sorbic acid glycerol mixture obtained in Step 1-2) with phosphoric acid, and react at 50-70℃ for 4-8 hours. Simultaneously, add a mixture of formic acid and hydrogen peroxide dropwise within 30-60 minutes of the start of the reaction. The mass percentage of phosphoric acid to unsaturated sorbic acid glycerol mixture is 0.5-2%:1. The molar amount of formic acid is 0.3-1.0 times the molar amount of carbon-carbon double bonds in the unsaturated sorbic acid glycerol mixture, and the molar amount of hydrogen peroxide is 1.1-2.5 times the molar amount of carbon-carbon double bonds in the unsaturated sorbic acid glycerol mixture.

[0041] Step 2-2): After the reaction is complete, the product is washed with water until neutral, then distilled under reduced pressure and dried to obtain a mixture of epoxy sorbic acid glycerol esters.

[0042] In this application, the plasticizer synthesis route is shown in formula (1).

[0043]

[0044] Where R is C3H7, C4H9, or C5H 11 C6H 13 C7H 15 One or more of them.

[0045] Preferably, in step 1-1), the C4-C8 monocarboxylic acid includes one or more straight-chain acids such as butyric acid, valeric acid, hexanoic acid, heptanoic acid, and octanoic acid.

[0046] Preferably, in step 1-1), the molar ratio of sorbic acid:C4-C8 straight-chain acid:glycerol is 0.77:2.25:1, or...

[0047] The molar ratio of sorbic acid:C4-C8 straight-chain acid:glycerol is 0.52:2.5:1, or...

[0048] The molar ratio of sorbic acid:C4-C8 straight-chain acid:glycerol is 0.27:2.75:1.

[0049] Preferably, the dehydrating agent is cyclohexane.

[0050] Preferably, in step 1), the esterification reaction is stirred at a speed of 400–800 r / min.

[0051] Preferably, the esterification reaction in step 1) is carried out in a three-necked flask equipped with a water separator, into which an appropriate amount of dehydrating agent is added. The amount of dehydrating agent added to the three-necked flask can be determined by those skilled in the art using common knowledge, for example, approximately 0.1% of the reactant volume.

[0052] Preferably, in steps 1-2), the catalyst is one of tetrabutyl titanate, a strong acid cation exchange resin, p-toluenesulfonic acid, and a solid superacid.

[0053] Secondly, this disclosure provides an epoxy plasticizer, which is prepared by the preparation method described above.

[0054] Thirdly, this disclosure also provides the application of epoxy plasticizers in the preparation of plastics. When applied to plastic products such as PVC and PLA, the plasticizers exhibit good thermal stability and mechanical properties.

[0055] Preferably, the plastics include, but are not limited to, PLA and PVC.

[0056] The present application will be further described in detail below with reference to embodiments:

[0057] Example 1

[0058] A method for preparing an epoxy plasticizer includes the following steps:

[0059] Step 1): Esterification reaction: including,

[0060] Step 1-1): 0.52 mol sorbic acid, 2.5 mol n-octanoic acid and 1 mol glycerol are placed in a three-necked flask. 5 ml of cyclohexane is added as a dehydrating agent. A water separator and condenser are installed. An appropriate amount of cyclohexane is added to the water separator. The mixture is magnetically stirred at a speed of 500 r / min. Nitrogen gas is continuously introduced (the mixture is placed below the liquid surface). The temperature is then gradually increased to 125-128℃ for about 5 minutes to dissolve the reactants.

[0061] Steps 1-2): Gradually raise the temperature to 140℃, add the catalyst tetrabutyl titanate (0.3% of the total mass of the reactants), and then continue to raise the temperature to 160℃ and react at a constant temperature for 10 hours. After the reaction is completed, wash the product with deionized water until neutral, and then perform vacuum distillation to remove the residual solvent and water to obtain the product unsaturated sorbic acid glycerol mixture (i.e., sorbic acid caprylic acid glycerol mixture).

[0062] Step 2): Epoxidation reaction: including,

[0063] Step 2-1): 50g of sorbic acid-caprylic acid glycerol mixture and 0.5g of phosphoric acid are placed in a four-necked round-bottom flask equipped with a spherical condenser, thermometer, and constant-pressure dropping funnel. 5.25g (0.114mol, 0.5C=C) of formic acid and 38.76g (0.342mol, 1.5C=C) of 30wt% hydrogen peroxide are added dropwise within 60min from the start of the reaction. The reaction is stopped after 6h at 60℃.

[0064] Step 2-2): After the reaction is complete, the product is washed with water until neutral, and then dried by vacuum distillation to obtain a mixture of epoxy sorbic acid and caprylic acid glycerol, i.e., epoxy plasticizer.

[0065] Example 2

[0066] A method for preparing an epoxy plasticizer includes the following steps:

[0067] Step 1): Esterification reaction: including,

[0068] Step 1-1): 0.27 mol sorbic acid, 2.75 mol n-octanoic acid and 1 mol glycerol are placed in a three-necked flask. 5 ml of cyclohexane is added as a dehydrating agent. A water separator and a condenser are installed. An appropriate amount of cyclohexane is added to the water separator. The mixture is magnetically stirred at 800 r / min. Under continuous nitrogen gas (within the liquid surface), the mixture is gradually heated to 128 °C for about 5 min to dissolve the reactants.

[0069] Steps 1-2): Gradually raise the temperature to 140℃, add the catalyst tetrabutyl titanate (0.1% of the total mass of the reactants), and then continue to raise the temperature to 190℃ and react at a constant temperature for 8 hours. After the reaction is completed, wash the product with deionized water until neutral, and then perform vacuum distillation to remove the residual solvent and water to obtain the product unsaturated sorbic acid glycerol mixture (i.e., sorbic acid caprylic acid glycerol mixture).

[0070] Step 2): Epoxidation reaction: including,

[0071] Step 2-1): 50g of sorbic acid-caprylic acid glycerol mixture and 0.5g of phosphoric acid are placed in a four-necked round-bottom flask equipped with a spherical condenser, thermometer, and constant-pressure dropping funnel. 1.27g (0.0275mol, 0.5C=C) of formic acid and 9.35g (0.0825mol, 1.5C=C) of 30wt% hydrogen peroxide are added dropwise within 60min from the start of the reaction. The reaction is stopped after 8h at 50℃.

[0072] Step 2-2): After the reaction is complete, the product is washed with water until neutral, and then dried by vacuum distillation to obtain a mixture of epoxy sorbic acid and caprylic acid glycerol.

[0073] Example 3

[0074] A method for preparing an epoxy plasticizer includes the following steps:

[0075] Step 1): Esterification reaction: including,

[0076] Step 1-1): 0.77 mol sorbic acid, 2.25 mol n-octanoic acid and 1 mol glycerol are placed in a three-necked flask. 5 ml of cyclohexane is added as a dehydrating agent. A water separator and condenser are installed. An appropriate amount of cyclohexane is added to the water separator. The mixture is magnetically stirred at a speed of 400 r / min. Nitrogen gas is continuously introduced (the mixture is placed below the liquid surface). The temperature is then gradually increased to 125℃ for about 5 minutes to dissolve the reactants.

[0077] Steps 1-2): Gradually raise the temperature to 140℃, add the catalyst tetrabutyl titanate (3% of the total mass of the reactants), and then continue to raise the temperature to 180℃ and react at a constant temperature for 10 hours. After the reaction is completed, wash the product with deionized water until neutral, and then perform vacuum distillation to remove the residual solvent and water to obtain the product unsaturated sorbic acid glycerol mixture (i.e., sorbic acid caprylic acid glycerol mixture).

[0078] Step 2): Epoxidation reaction: including,

[0079] Step 2-1): 50g of sorbic acid-caprylic acid glycerol mixture and 0.5g of phosphoric acid are placed in a four-necked round-bottom flask equipped with a spherical condenser, thermometer, and constant-pressure dropping funnel. 3.80g (0.0825mol, 0.5C=C) of formic acid and 28.05g (0.2475mol, 1.5C=C) of 30wt% hydrogen peroxide are added dropwise within 60min from the start of the reaction. The reaction is stopped after 4h at 70℃.

[0080] Step 2-2): After the reaction is complete, the product is washed with water until neutral, and then dried by vacuum distillation to obtain a mixture of epoxy sorbic acid and caprylic acid glycerol.

[0081] Example 4

[0082] A method for preparing an epoxy plasticizer includes the following steps:

[0083] Step 1): Esterification reaction: including,

[0084] Step 1-1): 0.52 mol sorbic acid, 2.5 mol n-butyric acid and 1 mol glycerol are placed in a three-necked flask. 5 ml of cyclohexane is added as a dehydrating agent. A water separator and a condenser are installed. An appropriate amount of cyclohexane is added to the water separator. The mixture is magnetically stirred at a speed of 500 r / min. Nitrogen gas is continuously introduced (the mixture is placed below the liquid surface). The temperature is then gradually increased to 128℃ for about 5 minutes to dissolve the reactants.

[0085] Steps 1-2): Gradually raise the temperature to 140℃, add the catalyst tetrabutyl titanate (0.3% of the total mass of the reactants), and then continue to raise the temperature to 150℃ and react at a constant temperature for 10 hours. After the reaction is completed, wash the product with deionized water until neutral, and then perform vacuum distillation to remove the residual solvent and water to obtain the product sorbate butyrate glycerol mixture.

[0086] Step 2): Epoxidation reaction: including,

[0087] Step 2-1): 50g of sorbate butyrate glycerol mixture and 0.5g of phosphoric acid are placed in a four-necked round-bottom flask equipped with a spherical condenser, thermometer, and constant-pressure dropping funnel. 3.6824g (0.08mol, 0.5C=C) of formic acid and 27.2g (0.24mol, 1.5C=C) of 30wt% hydrogen peroxide are added dropwise within 60min from the start of the reaction. The reaction is stopped after 6h at 60℃.

[0088] Step 2-2): After the reaction is complete, the product is washed with water until neutral, and then dried by vacuum distillation to obtain a mixture of epoxy sorbitol butyrate glycerol ester.

[0089] Example 5

[0090] The plasticizer prepared in Example 1 was used to prepare PVC test pieces, specifically through the following method:

[0091] PVC test pieces were prepared using a solvent molding method: 150 mL of tetrahydrofuran was measured using a graduated cylinder and poured into a 250 mL beaker. The mixture was magnetically stirred. 12.0 g of PVC resin powder was weighed and slowly added to the stirred tetrahydrofuran in one go. 6 g of plasticizer was then added. The beaker was sealed with plastic wrap and secured with a rubber band. The mixture was stirred continuously until the solution in the beaker became transparent and clear. The solution was then poured into a 15 cm diameter petri dish, covered with plastic wrap with a few small holes, and placed in a fume hood. After the tetrahydrofuran evaporated and the PVC film formed, the plastic wrap was removed. After all the tetrahydrofuran had evaporated, the PVC test piece (i.e., Example 1 - epoxy sorbate caprylic / octanoic acid glycerol mixture / PVC test piece) was obtained.

[0092] Example 6

[0093] According to the preparation method of Example 5, the plasticizers prepared in Examples 2-4 were used to prepare corresponding PVC sheets, resulting in Example 2-epoxy sorbate caprylic glycerol mixture / PVC test sheet, Example 3-epoxy sorbate caprylic glycerol mixture / PVC test sheet, and Example 4-epoxy sorbate butyric acid glycerol mixture / PVC test sheet.

[0094] Comparative Example

[0095] This comparative example is largely the same as Example 5, except that the plasticizer prepared in Example 1 was replaced with DOTP, ATBC, and DEHP to prepare DOTP / PVC, ATBC / PVC, and DEHP / PVC, respectively.

[0096] The plasticizer prepared in Example 1 was subjected to Fourier transform infrared (FT-IR) spectroscopy testing; and the PVC test pieces prepared in Example 5 and the PVC test pieces prepared in the comparative example were subjected to mechanical property, thermal stability, static thermal aging performance analysis, migration resistance and toxicity comparison tests.

[0097] The required equipment and instruments include: Thermogravimetric analyzer (TG), 209F3 Netzsch, a German company;

[0098] Servo-controlled tensile testing machine, AI-7000-LA10, manufactured by China High Speed ​​Rail Technology Co., Ltd.

[0099] Total reflectance Fourier transform infrared spectroscopy (FTIR) measurement: 32 scans, 4 cm⁻¹ resolution -1 The scanning range is set to 500–4000 cm. -1 .

[0100] The test conditions are as follows:

[0101] Thermal stability test: The test atmosphere was N2, the flow rate was 50 mL / min, and 8-10 mg of sample was taken and analyzed between 50-600℃. The heating rate was 20℃ / min to obtain the thermal stability data of the sample.

[0102] Mechanical property testing: The test was conducted in accordance with the standard ISO 527-5:2009. Dumbbell-shaped PVC samples were cut using a mold. The sample size was 10mm×2mm×1mm. The tensile rate was 50mm / min. Each sample was tested in parallel three times, and the average value was taken as the final result.

[0103] Static thermal aging test: The test was conducted in accordance with the standard GB / T 9349—2002. The PVC test piece was cut into a square piece of appropriate size and placed in an oven at 180℃ for the test. The test piece was taken out at certain intervals and the color change was recorded. The time of the black aging decomposition point (before basically turning black) of the sample was recorded as the static thermal aging time of PVC.

[0104] Migration resistance test: Water was selected as the solvent and the test was conducted according to standard ISO 175-2011. The PVC test piece was cut into square pieces of appropriate size, dried in a desiccator, and the mass of the PVC piece was accurately weighed and recorded as W0 in g. Then the PVC piece was immersed in the solvent water and tested at 30℃. It was taken out at intervals, the solvent was wiped clean, and it was dried in an oven at 40℃. After drying, it was taken out and allowed to cool to room temperature before weighing its mass and recording it as W in g. In order to reduce the error, the mass loss rate of 3 groups of samples was calculated for the same PVC sample, and the average value was taken as the final result. The mass loss rate η2 of the PVC piece (in %) was calculated according to formula (2):

[0105]

[0106] Hexane was selected as the food simulant to simulate fatty foods. In accordance with the requirements of 82 / 711 / EEC, PVC samples were placed in the food simulant solution (hexane) for migration resistance testing. The test method and calculation method were similar to those for migration resistance testing using water as the solvent.

[0107] The results are as follows:

[0108] 1: FTIR

[0109] The plasticizer prepared in Example 1 was subjected to infrared spectroscopy testing, and the results are as follows: Figure 1 As shown, where Figure 1 In Example 1, the sorbic acid caprylic acid glycerol mixture was obtained only through step 1) of esterification reaction.

[0110] from Figure 1 From this, we can learn that 1740cm -1 The peak at 1645 cm⁻¹ represents the stretching vibration of the C=O bond in the ester group, indicating the esterification reaction is underway. Comparing the mixed sorbate and glyceryl caprylate esters, the peak at 1645 cm⁻¹ after epoxidation is [missing value]. -1 The peak disappeared at 1645cm. -1 The peak at this point represents the stretching vibration of the C=C bond, indicating a good epoxidation reaction. Referring to GB / T 1677-2008 "Determination of Epoxy Value of Plasticizers," the epoxy value of Example 1—an epoxy sorbate-caprylic acid glycerol mixture—was tested. The average of three test results was taken as the final result, yielding an epoxy value of 0.6133% for Example 1—also indicating a successful epoxidation reaction. However, due to the relatively small number of C=C bonds, the epoxy value is low. Therefore, combined with… Figure 1 It can be seen that the plasticizer of Example 1 was successfully prepared.

[0111] II. Mechanical Properties:

[0112] The results are as follows Figure 2 As shown in Table 1,

[0113] Table 1 Tensile properties of PVC specimens with different plasticizers

[0114]

[0115] As shown in Table 1 and Figure 2 As shown, the tensile strength of Example 1—a mixture of epoxy sorbitol caprylic / caprylic acid glycerol / PVC—is superior to that of DEHP / PVC, DOTP / PVC, and ATBC / PVC. Simultaneously, Example 1—a mixture of epoxy sorbitol caprylic / caprylic acid glycerol / PVC—also exhibits good elongation at break, significantly better than DOTP / PVC and ATBC / PVC, but slightly lower than DEHP / PVC. The high tensile strength and elongation at break contribute to the processing and performance of PVC. Its excellent mechanical properties make it a viable alternative to DEHP.

[0116] Three: Thermal stability

[0117] The results are as follows Figure 3 As shown, the PVC specimens exhibited two main thermogravimetric (TG) loss stages. The first stage, occurring at approximately 160-400℃, primarily involved the decomposition of the plasticizer and the generation of HCl from PVC decomposition. The second stage, at approximately 400-550℃, mainly involved the structural reorganization of the PVC macromolecules and the breakage of the carbon skeleton. The TG plot clearly shows that the thermal stability of Example 1—a mixture of epoxy sorbitol and caprylic / glycerol esters / PVC—is superior to that of DEHP / PVC and ATBC / PVC, and comparable to that of DOTP, which also has good thermal stability.

[0118] IV. Static thermal aging performance analysis

[0119] like Figure 4 The image shows the color change of PVC test pieces observed using the thermal aging method.

[0120] The static heat aging results show that Example 1 - glyceryl sorbate-caprylate mixture / PVC started to turn noticeably red after 80 minutes, while Example 1 - epoxy glyceryl sorbate-caprylate mixture / PVC only started to turn noticeably red after 140 minutes. The static heat aging results indicate that the addition of epoxy bonds to the plasticizer can improve the heat aging resistance of the PVC sheet. This is because epoxy bonds have a certain flame retardant ability; during the decomposition of PVC, epoxy bonds can quickly absorb the HCl molecules released during PVC decomposition, preventing further decomposition of PVC.

[0121] 5. Migration Resistance Test

[0122] The migration resistance of Example 1—a mixture of epoxy sorbitol and caprylic / glycerol esters / PVC—was tested in water and n-hexane solvents. Figure 5 As shown, the mass loss rate of all PVC test pieces in water was less than 3%, meeting the requirements. Figure 6 As shown, in the migration resistance test using n-hexane as a simulated liquid for oily foods, the mass loss rate of Example 1-epoxysorbate caprylic acid glycerol mixture / PVC was less than that of DEHP / PVC and DOTP / PVC, indicating that its migration resistance performance was superior to that of DEHP / PVC and DOTP / PVC.

[0123] 6. Toxicity Comparison

[0124] The raw materials for the sorbic acid glycerol mixture and epoxy sorbic acid glycerol mixture in this application are derived from bio-based materials. Like ATBC, they are non-toxic and environmentally friendly. ATBC is also an FDA (Food and Drug Administration) approved non-toxic and safe plasticizer. The reproductive toxicity and potential carcinogenicity of DEHP are widely recognized, and countries such as the EU and the US have set strict regulations to restrict DEHP. DOTP molecules also have a benzene ring structure, and it is speculated that they also have some toxicity.

[0125] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this disclosure can be achieved, and this is not limited herein.

[0126] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0127] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A method for preparing an epoxy plasticizer, characterized in that: include: Step 1): Esterification reaction: including, Step 1-1): Mix the reactants and an appropriate amount of dehydrating agent, and continuously purge nitrogen gas under the liquid surface, gradually raising the temperature to 125-128°C to dissolve the reactants; wherein the reactants are sorbic acid, C4-C8 monocarboxylic acids and glycerol, and the molar ratio of sorbic acid, C4-C8 monocarboxylic acids and glycerol is 0.27-0.77:2.25-2.75:1; the C4-C8 monocarboxylic acids are one or more straight-chain acids selected from butyric acid, valeric acid, hexanoic acid, heptanoic acid and octanoic acid; wherein the dehydrating agent is cyclohexane; Steps 1-2): Gradually raise the temperature to 130-140℃, add the catalyst, and then continue to raise the temperature to 150-190℃ and react at a constant temperature for 8-10 hours; after the reaction is completed, wash with water until neutral, and then distill under reduced pressure to obtain unsaturated sorbic acid glycerol mixed ester; wherein, the catalyst is 0.1-3% of the total mass of the reactants; the catalyst is tetrabutyl titanate; Step 2): Epoxidation reaction: including, Step 2-1): Mix the unsaturated sorbic acid glycerol mixture obtained in Step 1-2) with phosphoric acid, and react at 50-70℃ for 4-8 hours. Simultaneously, add a mixture of formic acid and hydrogen peroxide dropwise within 30-60 minutes from the start of the reaction. The mass ratio of phosphoric acid to unsaturated sorbic acid glycerol mixture is 0.5-2 wt%:

1. The molar amount of formic acid is 0.3-1.0 times the molar amount of carbon-carbon double bonds in the unsaturated sorbic acid glycerol mixture, and the molar amount of hydrogen peroxide is 1.1-2.5 times the molar amount of carbon-carbon double bonds in the unsaturated sorbic acid glycerol mixture. Step 2-2): After the reaction is complete, the product is washed with water until neutral, then distilled under reduced pressure and dried to obtain a mixture of epoxy sorbic acid glycerol esters.

2. The preparation method according to claim 1, characterized in that: In step 1-1), The molar ratio of sorbic acid:C4-C8 straight-chain acid:glycerol is 0.77:2.25:1, or... The molar ratio of sorbic acid:C4-C8 straight-chain acid:glycerol is 0.52:2.5:1, or... The molar ratio of sorbic acid:C4-C8 straight-chain acid:glycerol is 0.27:2.75:

1.

3. The preparation method according to claim 1 or 2, characterized in that: In step 1), the esterification reaction is stirred at a speed of 400-800 r / min.

4. The preparation method according to claim 1 or 2, characterized in that: The esterification reaction in step 1) is carried out in a flask equipped with a water separator, and an appropriate amount of water-removing agent is added to the water separator.

5. An epoxy plasticizer, characterized in that: It is prepared by the preparation method described in any one of claims 1-4.

6. The application of the epoxy plasticizer according to claim 5 in the preparation of plastics.

7. The application according to claim 6, characterized in that: The plastics mentioned include PLA and PVC.

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