A natural monophenol grafted dimer acid diglycidyl ester plasticizer, and a preparation method and application thereof

Abstract

The application discloses a natural monophenol grafted dimer acid diglycidyl ester plasticizer and a preparation method and application thereof, and belongs to the technical field of bio-based plasticizers. The natural monophenol grafted dimer acid diglycidyl ester is synthesized by ring-opening etherification of dimer acid diglycidyl ester and natural monophenol. The prepared natural monophenol grafted dimer acid diglycidyl ester has a high-polarity hydroxyl group, a good-flexibility ether bond group and a compatibilized benzene ring group in the structure, and can endow a PLA product with excellent ductility and migration resistance. The application not only realizes high-value utilization of the natural monophenol in the material field, but also provides a new method for preparing a high-quality environment-friendly plasticizer, and has good practicability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of bio-based plasticizers, and more particularly relates to a natural monophenol grafted dimer acid diglycidyl ester plasticizer, a preparation method and application thereof. BACKGROUND

[0002] With the increasing pollution of non-degradable plastics to the environment and the introduction and upgrading of "plastic restriction order" in various countries, how to minimize the impact of plastics on the environment has become a hot research topic. Polylactic acid (PLA) is considered a green alternative to traditional petroleum-based plastics due to its excellent mechanical properties, good biocompatibility, biodegradability, and relatively low price, and has been widely used in food packaging, agriculture, textiles and clothing, medical devices, and automobile manufacturing. However, PLA has the problems of high brittleness and poor flexibility, and generally needs to be modified to meet the needs of industrial applications. Currently, the main methods for modifying PLA include chemical graft copolymerization, blending with high molecular materials, and plasticizer plasticization; among them, chemical copolymerization is complex and costly, and is difficult to be applied industrially; and after blending with high molecular materials, PLA is prone to phase separation, and the mechanical properties are limited. Compared with the above methods, the use of plasticizers to modify PLA has the advantages of simple process, low cost, and excellent plasticizing performance, and has been widely used by domestic and foreign scholars.

[0003] Currently, the environmentally friendly plasticizers used for toughening and modifying PLA resins mainly include citric acid esters, polyethylene / propylene glycols, and vegetable oil acid esters. Vegetable oil is considered one of the ideal raw materials for preparing bio-based plasticizers due to its wide source, low price, non-toxicity, and biodegradability. However, the existing vegetable oil-derived plasticizers have a high proportion of non-polar groups (long-chain alkyl groups) in their structure, which leads to poor compatibility with PLA resins and causes problems such as migration and precipitation during use, limiting their application in high-end fields. Dimer fatty acid (referred to as "dimer acid") is a binary fatty acid obtained by Diels-Alder addition of vegetable oil acid, and the binary carboxylic acid and unsaturated double bond in its structure can be modified by introducing polar groups (such as ether bonds, ester groups, and epoxy groups) to effectively overcome the poor compatibility of traditional vegetable oil-based plasticizers with resin materials. At the same time, the cyclic structure and high molecular weight of dimer acid can significantly improve the heat resistance and anti-migration performance of its derived plasticizers. However, the dimer acid esters obtained by traditional modification methods (such as esterification with traditional petroleum-based fatty alcohols and epoxidation) still have limited compatibility with polymers (such as polyvinyl chloride), and cannot truly replace petroleum-based plasticizers. In addition, the reported dimer acid-derived plasticizers mainly use dimer acid and petroleum-based fatty alcohols as raw materials, which are not completely sustainable.

[0004] Cardanol and eugenol are two common natural monophenols, the former is mainly derived from agricultural and forestry waste "cashew nut shell", and the latter can be extracted from clove, bay leaf, nutmeg and cinnamon, which is low in price, degradable and does not exist with the problem of competing with people for food. Both of them contain a solubilizing benzene ring and an active phenolic hydroxyl group in their structure, which can be modified by chemical methods to prepare plasticizers with high plasticizing efficiency. At present, foreign countries have carried out deep processing and utilization of natural monophenols such as cardanol and eugenol, and developed many natural monophenol derived fine chemicals, but the development of natural monophenol derived high-end fine chemicals, especially fully biobased environmentally friendly plasticizers, still needs to be further deepened in China. SUMMARY

[0005] In view of the above problems existing in the prior art, the technical problems to be solved by the present application are to provide a preparation method of natural monophenol grafted dimer acid diglycidyl ester plasticizer, which uses dimer acid diglycidyl ester and natural monophenol to prepare natural monophenol grafted dimer acid diglycidyl ester, and has the characteristics of simple process, easy operation and environmental protection. Another technical problem to be solved by the present application is to provide a natural monophenol grafted dimer acid diglycidyl ester plasticizer prepared by the above method, which has the characteristics of good compatibility and high plasticizing efficiency. The present application also solves a technical problem to provide the application of the above natural monophenol grafted dimer acid diglycidyl ester as a plasticizer in the preparation of PLA plastic.

[0006] In order to solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0007] A preparation method of natural monophenol grafted dimer acid diglycidyl ester plasticizer, which uses dimer acid diglycidyl ester as raw material and synthesizes natural monophenol grafted dimer acid diglycidyl ester by ring-opening etherification with natural monophenol.

[0008] The preparation method of the natural monophenol grafted dimer acid diglycidyl ester plasticizer, the specific steps are: taking natural monophenol, dimer acid diglycidyl ester, solvent and catalyst, directly ring-opening etherification to synthesize; the crude product is obtained by vacuum distillation, neutralization and water washing, vacuum distillation to obtain natural monophenol grafted dimer acid diglycidyl ester;

[0009] The ring-opening etherification reaction temperature is 100-160℃, and the reaction time is 4-8h.

[0010] As a preferred, the natural monophenol is selected from any one of cardanol and eugenol.

[0011] As a preferred, the molar ratio of the dimer acid diglycidyl ester and the natural monophenol is 1:2-5.

[0012] As preferred, the solvent is selected from any one of xylene, ethyl acetate, cyclohexane, acetylacetone, toluene, and the amount of solvent is 50% to 100% of the mass of the dimer acid diglycidyl ester.

[0013] As preferred, the catalyst is selected from any one of sodium phenoxide and potassium hydroxide, and the amount of catalyst is 1.0% to 7.0% of the mass of the dimer acid diglycidyl ester.

[0014] The natural monophenol grafted dimer acid diglycidyl ester plasticizer prepared by the preparation method of the natural monophenol grafted dimer acid diglycidyl ester plasticizer.

[0015] The natural monophenol grafted dimer acid diglycidyl ester plasticizer is used as a PLA plasticizer.

[0016] The application process is as follows: PLA particles and the natural monophenol grafted dimer acid diglycidyl ester are dissolved in dichloromethane solvent, and are fully stirred until a transparent and uniform liquid is obtained; the above solution is poured into a glass culture dish, and the coating thickness is controlled to be 1 mm; after the solvent is volatilized, the above product is placed in an oven and dried at 40-50 DEG C until the weight is constant; and then a suitable product is prepared by using a hot press according to needs.

[0017] In the application, the mass ratio of the natural monophenol grafted dimer acid diglycidyl ester to PLA is 100:5-20.

[0018] Compared with the prior art, the application has the following beneficial effects:

[0019] 1) The natural monophenol grafted dimer acid diglycidyl ester is synthesized by a ring-opening etherification one-step method with dimer acid diglycidyl ester and natural monophenol as raw materials, and has the characteristics of simple process, easy operation and environmental protection.

[0020] 2) The application provides a natural monophenol grafted dimer acid diglycidyl ester plasticizer and a preparation method thereof.

[0021] 3) The monophenol grafted dimer acid diglycidyl ester plasticizer synthesized by the application can efficiently plasticize PLA resin and is not easy to migrate and separate out from the product.

[0022] 4) The application not only realizes the high-value utilization of natural monophenol in the material field, but also provides a new method for preparing high-performance, environmentally friendly bio-based plasticizers, which has good practicability. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 NMR spectrum of the CDGE product prepared for Example 1;

[0024] Figure 2 NMR spectrum of the CDGE product prepared for Example 2;

[0025] Figure 3 NMR spectrum of the CDGE product prepared for Example 3;

[0026] Figure 4 NMR spectrum of the CDGE product prepared for Example 4;

[0027] Figure 5 NMR spectrum of the EDGE product prepared for Example 5;

[0028] Figure 6 NMR spectrum of the EDGE product prepared for Example 6;

[0029] Figure 7 NMR spectrum of the EDGE product prepared for Example 7. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the application clearer, the application will be further described below in combination with specific examples. In the following examples, the technical means used are all conventional means known to those skilled in the art unless otherwise specified.

[0031] In the following examples, cardanol and eugenol were provided by Shanghai Maikelin Biochemical Technology Co., Ltd.; fully bio-based dimer acid diglycidyl ester (epoxy value 0.21 mol / 100g) was provided by Anhui Xinyuan Technology Co., Ltd.; dioctyl phthalate (DOP), dioctyl terephthalate (DOTP), diisononyl cyclohexane-1,2-dicarboxylate (DINCH), epoxy soybean oil (ESO), sodium phenylate, potassium hydroxide, dimethylbenzene, ethyl acetate, cyclohexane, acetylacetone, toluene, dichloromethane, were of analytical purity and were provided by Sinopharm Chemical Reagent Co., Ltd.; polylactic acid (PLA) was provided by the Institute of Solid State Physics, Chinese Academy of Sciences.

[0032] Example 1

[0033] Into a four-necked flask, 100.0 g of dimer acid diglycidyl ester, 89.8 g of cardanol, 50.0 g of toluene, and 1.0 g of sodium phenoxide were added, N2 was introduced, and the reaction was completed at 160°C for 8 h. Toluene in the system was removed by vacuum distillation to obtain a crude cardanol-grafted dimer acid diglycidyl ester product, sodium phenoxide was removed by water washing, and finally, the product was dehydrated and dried by vacuum distillation to obtain a refined cardanol-grafted dimer acid diglycidyl ester (CDGE) product. The results of the nuclear magnetic resonance spectrum are shown in FIG. 1. Figure 1

[0034] Example 2

[0035] Into a four-necked flask, 100.0 g of dimer acid diglycidyl ester, 89.8 g of cardanol, 100.0 g of toluene, and 3.0 g of sodium phenoxide were added, N2 was introduced, and the reaction was completed at 140°C for 6 h. Toluene in the system was removed by vacuum distillation to obtain a crude cardanol-grafted dimer acid diglycidyl ester product, sodium phenoxide was removed by water washing, and finally, the product was dehydrated and dried by vacuum distillation to obtain a refined cardanol-grafted dimer acid diglycidyl ester (CDGE) product. The results of the nuclear magnetic resonance spectrum are shown in FIG. 2. Figure 2

[0036] Example 3

[0037] Into a four-necked flask, 100.0 g of dimer acid diglycidyl ester, 89.8 g of cardanol, 50.0 g of acetylacetone, and 5.0 g of potassium hydroxide were added, N2 was introduced, and the reaction was completed at 140°C for 4 h. Acetylacetone in the system was removed by vacuum distillation to obtain a crude cardanol-grafted dimer acid diglycidyl ester product, sodium phenoxide was removed by water washing, and finally, the product was dehydrated and dried by vacuum distillation to obtain a refined cardanol-grafted dimer acid diglycidyl ester (CDGE) product. The results of the nuclear magnetic resonance spectrum are shown in FIG. 3. Figure 3

[0038] Example 4

[0039] Into a four-necked flask, 100.0 g of dimer acid diglycidyl ester, 89.8 g of cardanol, 60.0 g of ethyl acetate, and 5.0 g of sodium phenoxide were added, N2 was introduced, and the reaction was completed at 100°C for 6 h. Ethyl acetate in the system was removed by vacuum distillation to obtain a crude cardanol-grafted dimer acid diglycidyl ester product, sodium phenoxide was removed by water washing, and finally, the product was dehydrated and dried by vacuum distillation to obtain a refined cardanol-grafted dimer acid diglycidyl ester (CDGE) product. The results of the nuclear magnetic resonance spectrum are shown in FIG. 4. Figure 4

[0040] Example 5

[0041] ​​​​Into a four-necked flask, 100.0 g of dimer acid diglycidyl ester, 48.8 g of eugenol, 100.0 g of xylene, 5.0 g of sodium phenolate were added, N2 was introduced, the reaction was completed after 5 h at 140℃. The xylene in the system was removed by vacuum distillation to obtain the crude product of eugenol grafted dimer acid glycidyl ester, the sodium phenolate was removed by water washing, and finally the product was dehydrated and dried by vacuum distillation to obtain the refined product of eugenol grafted dimer acid glycidyl ester (EDGE), the results of the nuclear magnetic resonance spectrum are shown in Figure 5 .

[0042] Example 6

[0043] Into a four-necked flask, 100.0 g of dimer acid diglycidyl ester, 73.2 g of eugenol, 80.0 g of acetylacetone, 5.0 g of potassium hydroxide were added, N2 was introduced, the reaction was completed after 6 h at 120℃. The acetylacetone in the system was removed by vacuum distillation to obtain the crude product of eugenol grafted dimer acid glycidyl ester, the sodium phenolate was removed by water washing, and finally the product was dehydrated and dried by vacuum distillation to obtain the refined product of eugenol grafted dimer acid glycidyl ester (EDGE), the results of the nuclear magnetic resonance spectrum are shown in Figure 6 .

[0044] Example 7

[0045] Into a four-necked flask, 100.0 g of dimer acid diglycidyl ester, 122.0 g of eugenol, 100.0 g of cyclohexane, 7.0 g of sodium phenolate were added, N2 was introduced, the reaction was completed after 5 h at 100℃. The cyclohexane in the system was removed by vacuum distillation to obtain the crude product of eugenol grafted dimer acid glycidyl ester, the sodium phenolate was removed by water washing, and finally the product was dehydrated and dried by vacuum distillation to obtain the refined product of eugenol grafted dimer acid glycidyl ester (EDGE), the results of the nuclear magnetic resonance spectrum are shown in Figure 7 .

[0046] Example 8

[0047] The PLA and the CDGE prepared in Example 1 above were dissolved in dichloromethane solvent according to the mass ratio m(CDGE):m(PLA)=5:100, and fully stirred until a certain luster, moderate viscosity and transparent uniform liquid was obtained. The above solution was poured into a glass culture dish, and the coating thickness was controlled to be 1 mm. After standing at room temperature for 3-4 days, after the solvent was volatilized, it was placed in a constant temperature drying oven with a temperature of 40-50℃ for 3-4 days, and dried to constant weight. The prepared PLA sheet was taken out, and finally 5 parallel PLA / CDGE (5%) samples were prepared by using a hot press according to the test needs.

[0048] Example 9

[0049] PLA and CDGE prepared in Example 1 above were dissolved in dichloromethane solvent at a mass ratio m(CDGE):m(PLA)=10:100, and stirred sufficiently until a uniform liquid with a certain gloss, moderate viscosity and transparency was obtained. The solution was poured into a glass dish, and the coating thickness was controlled to be about 1 mm. After standing at room temperature for 3-4 days, the solvent was evaporated, and the PLA sheet was placed in a constant temperature drying oven at a temperature of 40-50°C for 3-4 days until the weight was constant. The PLA sheet was taken out, and 5 parallel PLA / CDGE(10%) samples were prepared using a hot press according to the test requirements.

[0050] Example 10

[0051] PLA and CDGE prepared in Example 1 above were dissolved in dichloromethane solvent at a mass ratio m(CDGE):m(PLA)=20:100, and stirred sufficiently until a uniform liquid with a certain gloss, moderate viscosity and transparency was obtained. The solution was poured into a glass dish, and the coating thickness was controlled to be about 1 mm. After standing at room temperature for 3-4 days, the solvent was evaporated, and the PLA sheet was placed in a constant temperature drying oven at a temperature of 40-50°C for 3-4 days until the weight was constant. The PLA sheet was taken out, and 5 parallel PLA / CDGE(20%) samples were prepared using a hot press according to the test requirements.

[0052] Example 11

[0053] PLA and EDGE prepared in Example 5 above were dissolved in dichloromethane solvent at a mass ratio m(EDGE):m(PLA)=20:100, and stirred sufficiently until a uniform liquid with a certain gloss, moderate viscosity and transparency was obtained. The solution was poured into a glass dish, and the coating thickness was controlled to be about 1 mm. After standing at room temperature for 3-4 days, the solvent was evaporated, and the PLA sheet was placed in a constant temperature drying oven at a temperature of 40-50°C for 3-4 days until the weight was constant. The PLA sheet was taken out, and 5 parallel PLA / EDGE(20%) samples were prepared using a hot press according to the test requirements.

[0054] Preparation of Comparative Samples:

[0055] Comparative Sample 1: Polylactic acid (PLA) and dioctyl phthalate (DOP) were dissolved in dichloromethane solvent at a mass ratio m(DOP):m(PLA)=20:100, and stirred sufficiently until a uniform liquid with a certain gloss, moderate viscosity and transparency was obtained. The solution was poured into a glass dish, and the coating thickness was controlled to be 1 mm. After standing at room temperature for 3-4 days, the solvent was evaporated, and the PLA sheet was placed in a constant temperature drying oven at a temperature of 40-50°C for 3-4 days until the weight was constant. The PLA sheet was taken out, and 5 parallel PLA / DOP(20%) samples were prepared using a hot press according to the test requirements.

[0056] Comparative Sample 2: Polylactic acid (PLA) and dioctyl terephthalate (DOTP) were dissolved in dichloromethane solvent at a mass ratio of m(DOTP):m(PLA) = 20:100, and stirred thoroughly until a uniform liquid with a certain luster, moderate viscosity and transparency was obtained. The solution was poured into a glass dish, and the coating thickness was controlled to be 1 mm. After standing at room temperature for 3-4 days, the solvent was evaporated, and the PLA sheet was placed in a constant temperature drying oven at a temperature of 40-50°C for 3-4 days until the weight was constant. The PLA sheet was taken out. Five parallel PLA / DOTP (20%) samples were prepared using a hot press as needed.

[0057] Comparative Sample 3: Polylactic acid (PLA) and diisononyl cyclohexane-1,2- dicarboxylate (DINCH) were dissolved in dichloromethane solvent at a mass ratio of m(DINCH):m(PLA) = 20:100, and stirred thoroughly until a uniform liquid with a certain luster, moderate viscosity and transparency was obtained. The solution was poured into a glass dish, and the coating thickness was controlled to be 1 mm. After standing at room temperature for 3-4 days, the solvent was evaporated, and the PLA sheet was placed in a constant temperature drying oven at a temperature of 40-50°C for 3-4 days until the weight was constant. The PLA sheet was taken out. Five parallel PLA / DINCH samples were prepared using a hot press as needed.

[0058] Comparative Sample 4: Polylactic acid (PLA) and epoxidized soybean oil (ESO) were dissolved in dichloromethane solvent at a mass ratio of m(ESO):m(PLA) = 20:100, and stirred thoroughly until a uniform liquid with a certain luster, moderate viscosity and transparency was obtained. The solution was poured into a glass dish, and the coating thickness was controlled to be 1 mm. After standing at room temperature for 3-4 days, the solvent was evaporated, and the PLA sheet was placed in a constant temperature drying oven at a temperature of 40-50°C for 3-4 days until the weight was constant. The PLA sheet was taken out. Five parallel PLA / ESO samples were prepared using a hot press as needed.

[0059] The application performance evaluation is shown in Table 1

[0060] Table 1. Application performance evaluation

[0061]

[0062]

[0063] In the table, a The glass transition temperature (T g ) was obtained from the differential scanning calorimetry (DSC) curve; b The elongation at break and tensile strength were determined by a universal testing machine; cThe thermal decomposition temperature of the plasticized PLA product is 5% of mass loss.

[0064] As shown in Table 1, the plasticizer prepared by the application can significantly improve the ductility of polylactic acid (PLA). Compared with traditional commercially available plasticizers (dioctyl phthalate (DOP), dioctyl terephthalate (DOTP), diisononyl cyclohexane-1,2-dicarboxylate (DINCH), and epoxy soybean oil (ESO)), the thermal stability is better, the plasticizing efficiency is better, and the plasticizer has the potential to completely replace commercially available plasticizers.

Claims

1. A process for the preparation of natural monophenol grafted dimer acid diglycidyl ester plasticizers, characterized by, The natural monophenol grafted dimer acid diglycidyl ester is synthesized by ring-opening etherification of dimer acid diglycidyl ester and natural monophenol; the natural monophenol is selected from any one of cardanol and eugenol; and the molar ratio of the dimer acid diglycidyl ester and the natural monophenol is 1:2-5.

2. The method of making natural monophenol grafted dimer acid diglycidyl ester plasticizers according to claim 1, characterized in that, The specific steps are as follows: the natural monophenol, the dimer acid diglycidyl ester, a solvent and a catalyst are directly subjected to ring-opening etherification to synthesize; and the crude product is subjected to vacuum distillation, neutralization and water washing and vacuum distillation to obtain the natural monophenol grafted dimer acid diglycidyl ester. The ring-opening etherification reaction temperature is 100-160℃, and the reaction time is 4-8h.

3. The method of making natural monophenol grafted dimer acid diglycidyl ester plasticizer according to claim 2, characterized in that, The solvent is selected from any one of dimethylbenzene, ethyl acetate, cyclohexane, acetylacetone and toluene, and the amount of the solvent is 50%-100% of the mass of the dimer acid diglycidyl ester.

4. The method of making natural monophenol grafted dimer acid diglycidyl ester plasticizer according to claim 2, characterized in that, The catalyst is selected from any one of sodium phenoxide and potassium hydroxide, and the amount of the catalyst is 1.0%-7.0% of the mass of the dimer acid diglycidyl ester.

5. The preparation method of the natural monophenol grafted dimer acid diglycidyl ester plasticizer according to any one of claims 1-4, and the obtained natural monophenol grafted dimer acid diglycidyl ester.

6. The application of the natural monophenol grafted dimer acid diglycidyl ester according to claim 5 as a PLA plasticizer.

7. Use according to claim 6, characterized in that, The process is as follows: PLA particles and the natural monophenol grafted dimer acid diglycidyl ester are dissolved in dichloromethane solvent, and are fully stirred until a transparent and uniform liquid is obtained; the solution is poured into a glass culture dish, and the coating thickness is controlled to be 1mm; after the solvent is volatilized, the product is placed in an oven and dried at 40-50℃ until the weight is constant; and then a suitable product is prepared by using a hot press according to needs.

8. Use according to claim 7, characterized in that, The mass ratio of the natural monophenol grafted dimer acid diglycidyl ester and PLA is 100:5-20.

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