A medium-long / short-chain isosorbide-based structural lipid plasticizer and preparation method thereof

Abstract

The present invention discloses a medium-chain / short-chain isosorbide-based structural lipid plasticizer and its preparation method, belonging to the field of plastic additives. The invention utilizes aromatic isosorbide with medium-chain fatty acids and short-chain fatty acids through esterification and acylation reactions to produce the medium-chain / short-chain fatty acid isosorbide-based structural lipid. The lipid has a chemical structure and physicochemical properties similar to those of phthalate plasticizers and is renewable, green, non-toxic, and biodegradable. Its structure is as follows: #imgabs0#n=6-16;m=0-5.

Description

Technical Field

[0001] The invention relates to a medium-long / short-chain isosorbide-based structural lipid plasticizer and a preparation method thereof, belonging to the field of plastic additives. Background Art

[0002] Against the backdrop of achieving carbon peak and carbon neutrality, bio-based plasticizers are poised to replace petroleum-based plasticizers. Phthalate plasticizers are potentially toxic and carcinogenic, posing a significant threat to human health and the ecological environment. Biomass-derived bio-based plasticizers, being green, non-toxic, and biodegradable, hold great promise for development.

[0003] Isosorbide-based plasticizers, derived from cellulose, glucose, and oils, are renewable, non-toxic, and biodegradable. They possess similar chemical structures and physicochemical properties to phthalate-based plasticizers. They also offer advantages such as designability, good compatibility with PVC and PLA, excellent mechanical properties, a low glass transition temperature, excellent thermal stability, low volatility, low migration, and extraction resistance. Therefore, the development of these plasticizers holds great practical value. Li Wenbo, Ren Liang, Tao Zijun, and others studied the "Preparation of Isosorbide-Based Plasticizers and Their Plasticized PVC Properties" (Engineering Plastics Applications, Issue 4, 2021). They synthesized a new bio-based plasticizer, isosorbide di-nonanoate (SDN), from isosorbide and nonanoic acid to modify polyvinyl chloride (PVC) resin. They studied the plasticizing effect of the green plasticizer and its effect on the properties of the blend. However, SDN is not designable and cannot meet the different formulation requirements of PVC. It also has poor compatibility and migration with PLA. There are currently no reports on medium- and long-chain / short-chain fatty acid isosorbide structural lipid plasticizers. Summary of the Invention

[0004] The present invention aims to provide a medium-long / short-chain fatty acid isosorbide structured fat plasticizer.

[0005] To achieve the purpose of the present invention, the technical solution is as follows:

[0006] The structure of the medium-long / short-chain fatty acid isosorbide structural fat plasticizer is as follows: n=6-16; m=0-5.

[0007] It is prepared by the following steps:

[0008] (1) Isosorbide and medium-chain fatty acids are placed in a reactor, a catalyst is added, and the temperature is raised under vacuum to carry out an esterification reaction. After the reaction is completed, the temperature is lowered, and the acid value is measured to be less than 3 to reach the end point, thereby obtaining an isosorbide mono-fatty acid ester. The molar ratio of isosorbide to medium-chain fatty acids is preferably 1:1. The reaction temperature is preferably 160-190°C.

[0009] (2) Gradually add the short-chain fatty acid anhydride to the above-mentioned isosorbide mono-fatty acid ester, add a catalyst, and heat to 120-140°C under vacuum to carry out the acylation reaction. After the reaction is completed, cool it down and measure the acid value to be less than 3 as the end point. The obtained crude product is filtered, washed, and refined by distillation. The molar ratio of isosorbide mono-fatty acid ester to short-chain fatty acid anhydride is preferably 1:1; the reaction temperature is preferably 130°C.

[0010] The catalyst is one or more of tetrabutyl phthalate, benzenesulfonic acid, phosphoric acid, phosphotungstate and the like.

[0011] The medium-chain fatty acid is a C8-18 saturated fatty acid, preferably caprylic acid, isooctanoic acid, capric acid, lauric acid, palmitic acid, epoxidized oleic acid or stearic acid.

[0012] The short-chain fatty acid anhydride is a C2-7 saturated fatty acid anhydride, preferably acetic anhydride, butyric anhydride, valeric anhydride or heptanoic anhydride.

[0013] Advantages of the present invention: The plasticizer is derived from biomass and is renewable, green, non-toxic, and biodegradable. It has a chemical structure and physicochemical properties similar to those of phthalate plasticizers. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The decomposition temperature curve of PVC test pieces with different plasticizers added;

[0015] Figure 2 The migration of plasticizers in different PVC test pieces in 95% by mass ethanol;

[0016] Figure 3 The bar graph shows the relationship between the volatilization loss rate of different plasticizers in PVC test pieces and time;

[0017] Figure 4 The migration of plasticizers in different PLA test pieces in 95% by mass ethanol:

[0018] Figure 5 This is a bar graph showing the relationship between the volatilization loss rate of different plasticizers in PLA specimens and time. DETAILED DESCRIPTION

[0019] In order to better illustrate the present invention, the following embodiments are given:

[0020] Example 1

[0021] (1) Isosorbide and octanoic acid are placed in a reactor at a molar ratio of 1:1, and a phosphotungstate catalyst is added. The temperature is raised to 160°C under vacuum for esterification. After reacting for 4-5 hours, the temperature is lowered to 60°C. The acid value is measured to be less than 3, reaching the end point, thereby obtaining isosorbide monofatty acid ester.

[0022] (2) Acetic anhydride is gradually added to the above-mentioned isosorbide monofatty acid ester at a molar ratio of 1:1, and a phosphotungstate catalyst is added at the same time. The reaction is heated at 130°C under vacuum for 2 hours to carry out the acylation reaction. After the reaction is completed, the temperature is lowered to 60°C. The end point is determined to be an acid value less than 3. The obtained crude product is filtered, washed, and purified by distillation.

[0023] Example 2

[0024] (1) Isosorbide and lauric acid are placed in a reactor at a molar ratio of 1:1, and benzenesulfonic acid catalyst is added. The temperature is raised to 180°C under vacuum for esterification. After reacting for 4-5 hours, the temperature is lowered to 60°C. The acid value is measured to be less than 3, reaching the end point, thereby obtaining isosorbide mono-fatty acid ester.

[0025] (2) Butyric anhydride is gradually added to the above-mentioned isosorbide monofatty acid ester at a molar ratio of 1:1, and benzenesulfonic acid catalyst is added at the same time. The acylation reaction is carried out at 130°C under vacuum for 2 hours. After the reaction is completed, the temperature is lowered to 60°C. The end point is determined to be an acid value less than 3. The obtained crude product is filtered, washed, and purified by distillation.

[0026] Example 3

[0027] (1) Isosorbide and epoxidized oleic acid are placed in a reactor at a molar ratio of 1:1, and benzenesulfonic acid catalyst is added. The temperature is raised to 170°C under vacuum for esterification. After reacting for 4-5 hours, the temperature is lowered to 60°C. The acid value is measured to be less than 3, reaching the end point, thereby obtaining isosorbide mono-fatty acid ester.

[0028] (2) Heptanoic anhydride is gradually added to the above-mentioned isosorbide monofatty acid ester at a molar ratio of 1:1, and benzenesulfonic acid catalyst is added at the same time. The acylation reaction is carried out at 130°C under vacuum for 2 hours. After the reaction is completed, the temperature is lowered to 60°C. The end point is determined to be an acid value less than 3. The obtained crude product is filtered, washed, and purified by distillation.

[0029] Application Example 1

[0030] The plasticizer prepared in the above embodiment is referred to as ISP for short. It is applied to PVC and the performance test is as follows:

[0031] 1. Compared with DOP, DOTP, TBC, ATBC, etc., ISP has the highest decomposition temperature and good thermal stability. Figure 1 and Table 1.

[0032] The decomposition temperatures of PVC test pieces with different plasticizers added are shown in the following table:

[0033] Table 1

[0034]

[0035] 2. According to EU food grade testing regulations food (EU) No. 1020116112, the migration rate of PVC test pieces with different plasticizers (ISP, DOP, DOTP TBC, ATBC) was tested. The results showed that in 95% by mass ethanol solution, ISP has a lower migration rate than DOP, DOTP, TBC, ATBC, etc. See the attached Figure 2 .

[0036] 3. According to the activated carbon method in HG / T 4458-2012, the volatile loss rate of PVC test pieces with different plasticizers (ISP, DOP, TBC, ATBC) was tested. The volatile loss rate of ISP test pieces was significantly lower than that of other product test pieces. See the attached Figure 3 .

[0037] 4. Mechanical strength test of PVC specimens with different plasticizers added:

[0038]

[0039] Application Example 2

[0040] Application in PLA:

[0041] 1. According to EU food grade testing regulations food (EU) No. 1020116112, a migration test experiment was conducted on PLA test pieces (plasticizer addition 20%). The results showed that compared with traditional plasticizers such as ESO, TBC, and ATBC, the migration rate of ISP test pieces was smaller. This shows that ISP has good compatibility with PLA materials. See attached. Figure 4 .

[0042] 2. According to the activated carbon method in HG / T 4458-2012, the volatility loss rate of PLA test pieces with different plasticizers (ISP, ESO, TBC, ATBC) was tested. The volatility loss rate of ISP test pieces was significantly lower than that of other product test pieces. See the attached Figure 5 .

Claims

1. An isosorbide-based plasticizer, characterized in that: The plasticizer is a medium-chain / short-chain fatty acid isosorbide ester, and its molecular structure is as follows: n=6-16;m=0-5;and is prepared by the following steps: (1) putting isosorbide and medium-chain fatty acids into a reactor, adding a catalyst, heating to 140-190° C. under vacuum to carry out esterification reaction, cooling after the reaction is completed, and measuring the acid value to be less than 3 to reach the end point, thereby obtaining isosorbide monofatty acid ester; the molar ratio of isosorbide to medium-chain fatty acids is 1:1; (2) gradually adding a short-chain fatty acid anhydride to the above-mentioned isosorbide monofatty acid ester, adding a catalyst at the same time, heating to 120-140° C. under vacuum for acylation reaction, cooling after the reaction, and determining the acid value less than 3 as the end point; filtering, washing, and distilling the obtained crude product; the molar ratio of the isosorbide monofatty acid ester to the short-chain fatty acid anhydride is 1:1; The catalyst is one or more of tetrabutyl phthalate, benzenesulfonic acid, phosphoric acid, and phosphotungstate; The medium-chain fatty acid is a C8-18 saturated fatty acid; The short-chain fatty acid anhydride is a C2-7 saturated fatty acid anhydride.

2. The isosorbide-based plasticizer according to claim 1, wherein The medium-chain fatty acid is selected from caprylic acid, isooctanoic acid, capric acid, lauric acid, palmitic acid, epoxidized oleic acid or stearic acid; the short-chain fatty acid anhydride is selected from acetic anhydride, butyric anhydride, valeric anhydride or heptanoic anhydride.

Images