Synthetic wool fat and preparation method thereof

Abstract

The invention discloses synthetic lanolin and a preparation method thereof, the preparation method of the synthetic lanolin comprises the following steps: 1) adding polyol, a plurality of monobasic fatty acid methyl esters, an antioxidant and a transesterification catalyst into a reaction kettle, heating under stirring and vacuum conditions, and carrying out transesterification until the acid value of the product is less than 1mgKOH / g; 2) adding one or more binary acids and an esterification catalyst, heating under stirring and vacuum conditions, and carrying out an esterification reaction until the acid value of the product is less than 1mgKOH / g; and 3) after cooling, decoloring, washing, deodorizing and dehydrating the product to obtain the synthetic lanolin finished product. The fatty acid ester, the polyhydric alcohol and the dibasic acid which are simple in structure are subjected to ester exchange reaction and esterification reaction to obtain the synthetic ester with a proper structure; the synthetic ester is light in color and almost free of odor, and meanwhile, the water absorption and moisture retention performance of the synthetic ester reaches or exceeds those of natural wool fat.

Description

Technical Field

[0001] The invention relates to the technical field of chemical synthesis, and in particular to synthetic lanolin and a preparation method thereof. Background Art

[0002] Lanolin is a multi-component mixture of lipid substances that adhere to wool and are secreted by the sebaceous glands of sheep. It is recovered from the waste liquid of wool washing and has good emulsification, permeability, water absorption and rust prevention properties. It can absorb twice its own weight of water in the air and has the effect of skin care and moisturizing. Therefore, it has a wide range of uses in medicine and cosmetics. Lanolin can be used as a base material for ointments in medicine, as a base material for hand creams, lipsticks and other products in the cosmetics field, and as one of the effective ingredients of lubricants and rust-proof oils in the field of lubricants and rust-proof oils to play an emulsifying and rust-proof role.

[0003] However, natural lanolin is dark in color and has a strong odor, and the polycyclic alcohols and some pesticide residues it contains can cause allergic reactions in certain groups of people. In existing methods, this problem is solved by refining natural lanolin, such as decolorizing, deodorizing and removing impurities through solvent extraction, impurity removal, sulfuric acid scouring, decolorization and bleaching, alkali refining and deacidification, deodorization and other processes, but the color and odor of the lanolin obtained in this way are still difficult to meet the requirements of cosmetic grade. Therefore, it is of great significance to use natural or synthetic raw materials to synthesize lanolin, which has the properties of water absorption, penetration, moisture retention and rust prevention at the same time as natural lanolin, and has a very light color and almost no smell.

[0004] The chemical composition of lanolin is different from that of ordinary animal and plant oils. It is a monoester structure formed by a variety of fatty acids, hydroxy fatty acids and roughly equal amounts of cholesterol, fatty alcohols, etc. Its structure is shown below:

[0005]

[0006] Wherein, R1 represents a fatty acid or a hydroxy fatty acid residue, and R2 represents a cholesterol or fatty alcohol residue.

[0007] The composition of lanolin alcohol and lanolin acid in lanolin from different origins also varies to a certain extent. The general composition is shown in Table 1:

[0008] Table 1 Composition of alcohols and acids in lanolin

[0009]

[0010] Chinese patent CN108893204A uses lanolin acid and lanolin alcohol obtained by hydrolysis and purification of lanolin as raw materials, and obtains lanolin by esterification reaction catalyzed by an alkaline catalyst, and then obtains lanolin after decolorization and washing. The structure and performance of the lanolin obtained in this way are highly similar to natural lanolin, and the color is lighter and there is no odor of natural lanolin. However, the raw materials refined lanolin acid and lanolin alcohol used are expensive, so the cost is high.

[0011] Chinese patent CN114591785A uses dimer acid as an acid component and a mixture of phytosterol, isostearyl alcohol, cetyl alcohol, stearyl alcohol and behenyl alcohol as an alcohol component to obtain dimer acid ester through esterification reaction. The obtained dimer acid ester has a lighter color and water absorption comparable to lanolin, and its moisture retention and glossiness also reach the level of lanolin. However, isostearyl alcohol, cetyl alcohol, stearyl alcohol and behenyl alcohol are relatively expensive, and organic solvents are used for washing in the reaction, which is complicated to operate and has solvent residues.

[0012] Chinese patent CN108485821A uses wool acid and wool alcohol to obtain lanolin through vacuum esterification, and then obtains synthetic lanolin through bleaching and water washing, but the raw material price is relatively high and the yield after water washing is average. Summary of the invention

[0013] In order to solve the above technical problems, the purpose of the present invention is to provide a synthetic lanolin and a preparation method thereof; the present invention uses simple-structured fatty acid esters, polyols, and dibasic acids to obtain a synthetic ester with a suitable structure through ester exchange reaction and esterification reaction; the synthetic ester is lighter in color and has almost no odor, and its water absorption and moisturizing properties reach or exceed those of natural lanolin.

[0014] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0015] One aspect of the present invention provides a method for preparing synthetic lanolin, comprising the following steps:

[0016] 1) adding polyols, various monobasic fatty acid methyl esters, antioxidants, and transesterification catalysts into a reaction kettle, heating the reaction kettle under stirring and vacuum conditions, and performing transesterification reaction until the acid value of the product is less than 1 mgKOH / g;

[0017] 2) adding one or more dibasic acids and an esterification catalyst, heating under stirring and vacuum conditions, and performing an esterification reaction until the acid value of the product is less than 1 mgKOH / g;

[0018] 3) After cooling, the product is subjected to decolorization, washing, deodorization and dehydration treatment to obtain the finished synthetic lanolin product.

[0019] Furthermore, the reaction temperature of step 1) is 120-150° C., the reaction time is 4-12 hours, and the molar ratio of the polyol to the monobasic fatty acid methyl ester is 1:(1.5-4.5).

[0020] Furthermore, the reaction temperature of step 2) is 150-180° C., the reaction time is 4-12 hours, and the molar ratio of the dibasic acid to the polyol is (0.5-0.9):1.

[0021] Furthermore, the reactions of step 1) and step 2) are both carried out under a vacuum degree greater than -0.095 MPa.

[0022] Preferably, the polyol is at least one of glycerol, diglycerol, triglycerol, tetraglycerol, pentaglycerol and hexaglycerol; the dibasic acid is at least one of succinic acid, adipic acid, sebacic acid and dimer acid; the monobasic fatty acid methyl ester is a mixture of multiple components of methyl caprylate, methyl laurate, methyl myristic acid, methyl palmitate, methyl stearate, methyl 12-hydroxystearate and methyl isostearate.

[0023] Preferably, the antioxidant is one or a mixture of two or more of butylated hydroxyanisole, butylated hydroxytoluene, 2,5-di-tert-butylhydroquinone, propyl gallate, vitamin E, and tert-butylhydroquinone, and its usage is 0.02%-0.2% of the total mass of the reaction raw materials.

[0024] Preferably, the transesterification catalyst is at least one of potassium hydroxide, sodium hydroxide, tetrabutyl titanate, and tetraisopropyl titanate, and its usage is 0.02%-0.05% of the total mass of the reaction raw materials.

[0025] Further, in step 3), the temperature is lowered to 120-150° C. for decolorization, and the temperature is lowered to 80° C. for washing.

[0026] Furthermore, the decolorizing agent used in the decolorization process is hydrogen peroxide; the washing process is first washed with alkali solution and then washed with distilled water, and the concentration of the alkali solution is 1%-15%; the deodorization process adopts steam deodorization, the steam temperature is 150-160℃, and the deodorization time is 0.5-2h.

[0027] Another aspect of the present invention provides a synthetic lanolin, which is prepared by the above-mentioned preparation method; the structure of the synthetic lanolin is shown in formula (I):

[0028]

[0029] In the structural formula (I), R3 represents the residue after dibasic acid esterification, R4 represents the residue after polyol reaction, and R5 and R6 represent the residue after monobasic fatty acid methyl ester undergoes ester exchange reaction.

[0030] The beneficial effects of the present invention are:

[0031] The present invention firstly adopts polyols and various fatty acid esters to carry out ester exchange reaction. Compared with the direct esterification reaction with fatty acids, the ester exchange reaction can significantly reduce the reaction temperature and improve the product color. The product obtained after the ester exchange reaction has certain hydrophobicity and moisture retention. On this basis, a polyester structure with a certain degree of polymerization is formed by adding dibasic acid and polyols, so that the product has good hydrophilicity. The present invention makes the synthetic ester reach the water absorption similar to that of natural lanolin through the design of molecular structure and raw material ratio. The present invention also adjusts the melting point of the final synthetic lanolin by adjusting the ratio of various monobasic fatty acid methyl esters with different melting points. After decolorization, washing, deodorization and dehydration treatment, the synthetic ester of the present invention has a lighter color and almost no odor, and its water absorption and moisture retention performance reaches or exceeds that of natural lanolin.

[0032] The present invention mainly uses natural animal and plant ingredients as raw materials, and the proportion of natural products in the finished product is as high as 85%-100%. Through appropriate structural design and raw material ratio adjustment, a synthetic lanolin with excellent performance is obtained, which can be used as a substitute for natural lanolin, and has a lighter color and no odor. The catalyst used in the preparation method is non-toxic to the human body, so there is no need for a catalyst removal process. The synthesis method is simple, and no organic solvent is used, and there is no solvent residue. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is the infrared spectrum of the synthetic lanolin of Example 1;

[0034] Figure 2 is the gel permeation chromatogram of the synthetic lanolin of Example 1;

[0035] Figure 3 is the infrared spectrum of the synthetic lanolin of Example 2;

[0036] Figure 4 is the gel permeation chromatogram of the synthetic lanolin of Example 2;

[0037] Figure 5 is the infrared spectrum of the synthetic lanolin of Example 3;

[0038] Figure 6 This is the gel permeation chromatogram of the synthetic lanolin of Example 3. DETAILED DESCRIPTION

[0039] The technical solutions in the present invention will be described clearly and completely below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] The present invention provides a method for preparing synthetic lanolin, comprising the following steps:

[0041] 1) Add polyols, various monobasic fatty acid methyl esters, antioxidants, and transesterification catalysts into a reaction kettle, raise the temperature to 120-150° C. under stirring and vacuum conditions, and perform transesterification reaction for 4-12 hours until the acid value of the product is less than 1 mgKOH / g;

[0042] 2) adding one or more dibasic acids and an esterification catalyst, raising the temperature to 150-180° C. under stirring and vacuum conditions, and carrying out the esterification reaction for 4-12 hours until the acid value of the product is less than 1 mgKOH / g;

[0043] 3) Cool down to 120-150°C, slowly add 5%-20% of the mass of the reaction raw material decolorizer, and keep warm for 3 hours after the addition is complete. At this time, the color of the product is colorless to light yellow;

[0044] 4) Cool down to 80°C, add alkali solution to wash and separate the water, then wash three times with distilled water and separate the water;

[0045] 5) Use steam to deodorize the product, and then vacuum dehydrate it to obtain the finished product.

[0046] In the above method, the molar ratio of polyol to monobasic fatty acid methyl ester is 1:(1.5-4.5), preferably 1:(1.8-2.2); the molar ratio of dibasic acid to polyol is (0.5-0.9):1, preferably (0.75-0.8):1.

[0047] The reactions of step 1) and step 2) are both carried out under a vacuum degree greater than -0.095 MPa.

[0048] The polyol is preferably at least one of glycerol, diglycerol, triglycerol, tetraglycerol, pentaglycerol, and hexaglycerol; the dibasic acid is at least one of succinic acid, adipic acid, sebacic acid, and dimer acid; the monobasic fatty acid methyl ester is preferably a mixture of multiple components of methyl caprylate, methyl laurate, methyl myristic acid, methyl palmitate, methyl stearate, methyl 12-hydroxystearate, and methyl isostearate. Preferably, it is a mixture including 12-hydroxystearic acid and methyl isostearate, 12-hydroxystearic acid has certain water absorption and moisture retention, and helps the finished product to form a three-dimensional hydrogen bond network after water absorption, which is more conducive to water absorption and moisture retention; methyl isostearate has good thermal stability, low temperature fluidity, solubility, and skin permeability, which can make the finished product have better moisturizing and emulsifying effects.

[0049] The antioxidant is preferably one or a mixture of two or more of butylated hydroxyanisole, butylated hydroxytoluene, 2,5-di-tert-butylhydroquinone, propyl gallate, vitamin E, and tert-butylhydroquinone, and its dosage is 0.02%-0.2% of the total mass of the reaction raw materials.

[0050] The transesterification catalyst is preferably at least one of potassium hydroxide, sodium hydroxide, tetrabutyl titanate, and tetraisopropyl titanate, and the amount thereof is 0.02%-0.05% of the total mass of the reaction raw materials. Potassium hydroxide and sodium hydroxide will be converted into potassium salt and sodium salt of fatty acids during the reaction, which are non-toxic and harmless; titanate catalysts will be converted into titanium dioxide during the steam deodorization stage after the reaction, which is non-toxic and harmless, so the use of this type of catalyst eliminates the step of removing the catalyst.

[0051] The decolorizing agent used in the decolorizing process is hydrogen peroxide; the alkali used in the alkali washing is one of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate, and the concentration of the alkali solution is 1%-15%; in the deodorizing process, the steam temperature is 150-160°C, and the deodorizing time is 0.5-2h.

[0052] The structure of the synthetic lanolin prepared by the above preparation method is shown in formula (I):

[0053]

[0054] In the structural formula (I), R3 represents the residue after dibasic acid esterification, R4 represents the residue after polyol reaction, and R5 and R6 represent the residue after monobasic fatty acid methyl ester undergoes ester exchange reaction.

[0055] Example 1

[0056] Diglycerol: adipic acid: methyl stearate: methyl 12-hydroxystearate: methyl octanedioate: methyl isostearate were reacted in a molar ratio of 1:0.8:1.03:0.3:0.47:0.15, with a total mass of 912 g. First, diglycerol, methyl stearate, methyl 12-hydroxystearate and methyl octanoate are added to the reactor, and then 0.8g of antioxidant propyl gallate is added; the temperature is started to rise, and stirring and vacuum are started after all the raw materials are melted, the temperature is raised to 120°C, and the water contained in the raw materials is removed by vacuum stirring for 1h; then 0.3g of tetrabutyl titanate catalyst is added, the temperature is gradually raised to 130°C, and the vacuum ester exchange reaction is performed for 8h. The acid value of the sample test is 0.77mgKOH / g; adipic acid and 0.3g of potassium hydroxide catalyst are added, the temperature is gradually raised to 160°C, and the vacuum ester exchange reaction is performed for 8h. The acid value of the sample test is 0.51mgKOH / g;

[0057] Cool down to 120°C, add 80g of hydrogen peroxide (25%) dropwise, complete the addition within 2h, and keep warm for 3h after the addition is completed; cool down to 80°C, add 900g of 5% potassium carbonate aqueous solution, stir for 1h, let stand for 2h, separate the water, and then repeat the above washing steps three times with 900g*3 distilled water respectively; heat up to 160°C, pass 400g of 160°C water vapor under vacuum for deodorization; then cool down to 120°C, vacuum dehydrate for 2h to remove residual water, and obtain the finished product, whose infrared spectrum and gel permeation chromatogram are as shown respectively. Figure 1 and Figure 2 shown.

[0058] like Figure 1 The infrared spectrum test diagram of the synthetic lanolin of Example 1 shown is: 1100-1200cm -1 The multiple peaks at 1735 cm are the COC stretching vibrations of the ester bonds formed by different fatty acids. -1 The stretching vibration of the carbonyl group on the ester bond is 2850-2950cm -1 The multiple peaks at are the stretching vibrations of methyl and methylene groups on fatty acids.

[0059] Example 2

[0060] Diglycerol: sebacic acid: methyl stearate: methyl 12-hydroxystearate: methyl octanedioate: methyl isostearate were reacted in a molar ratio of 1:0.96:0.98:0.4:0.15:0.2, with a total mass of 942 g. First, add diglycerol, methyl stearate, methyl 12-hydroxystearate, methyl caprylate and methyl isostearate into the reactor, and then add 1g of antioxidant propyl gallate; start heating, and start stirring and vacuum after all the raw materials are melted, raise the temperature to 120°C, and stir in vacuum for 1h to remove the moisture contained in the raw materials; then add 0.3g of tetrabutyl titanate catalyst, gradually raise the temperature to 130°C, and vacuum transesterify for 8h. The acid value of the sample test is 0.46mgKOH / g; add sebacic acid and 0.3g of potassium hydroxide catalyst, gradually raise the temperature to 160°C, and vacuum transesterify for 8h. The acid value of the sample test is 0.63mgKOH / g;

[0061] Cool down to 120°C, add 100g of hydrogen peroxide (25%) dropwise within 2h, and keep warm for 3h after the addition is completed; cool down to 80°C, add 900g of 5% potassium carbonate aqueous solution, stir for 1h, let stand for 2h, separate the water, and then repeat the above washing steps three times with 900g*3 distilled water respectively; heat up to 160°C, and pass 400g of 160°C water vapor under vacuum for deodorization; then cool down to 120°C, vacuum dehydrate for 2h to remove residual water, and obtain the finished product, whose infrared spectrum and gel permeation chromatogram are as shown respectively. Figure 3 and Figure 4 shown.

[0062] Example 3

[0063] Diglycerol: adipic acid: methyl palmitate: methyl 12-hydroxystearate: methyl octanedioate: methyl isostearate were reacted in a molar ratio of 1:0.8:1.03:0.3:0.47:0.15, with a total mass of 798 g. First, add diglycerol, methyl palmitate, methyl 12-hydroxystearate, methyl caprylate and methyl isostearate into the reactor, and then add 1g of antioxidant propyl gallate; start heating, and start stirring and vacuum after all the raw materials are melted, heat to 120°C, and stir in vacuum for 1h to remove the moisture contained in the raw materials; then add 0.3g of tetrabutyl titanate catalyst, gradually heat to 130°C, vacuum transesterification reaction for 8h, and the acid value of sampling test is 0.84mgKOH / g; add adipic acid and 0.3g of catalyst potassium hydroxide, gradually heat to 160°C, vacuum transesterification reaction for 8h, and the acid value of sampling test is 0.90mgKOH / g;

[0064] Cool down to 120°C, add 100g of hydrogen peroxide (25%) dropwise, and complete the addition within 2h. After the addition is completed, keep the temperature for reaction for 3h; cool down to 80°C, add 900g of 5% potassium hydroxide aqueous solution, stir for 1h, let stand for 2h, separate the water, and then repeat the above washing steps three times with 900g*3 distilled water respectively; heat up to 160°C, and pass 400g of 160°C water vapor under vacuum for deodorization; then cool down to 120°C, vacuum dehydrate for 2h, remove residual water, and obtain the finished product, whose infrared spectrum and gel permeation chromatogram are as shown respectively. Figure 5 and Figure 6 shown.

[0065] Application performance testing

[0066] The test method is as follows:

[0067] (1) Color: Visual color comparison using Gardner colorimetric standard solution;

[0068] (2) Water absorption rate: Add a sample with a mass of m1 into a 250 mL beaker, place it on a magnetic stirrer and heat it to 60°C. Use a graduated burette to add cold water, adding 0.1 g of water each time, until the sample stops absorbing water. Record the mass of water absorbed by the sample, m2. The water absorption rate of the sample is (m2 / m1)*100%.

[0069] The test results are shown in Table 2.

[0070] Table 2

[0071] sample Example 1 Example 2 Example 3 Refined Lanolin Gardner Chroma 1 2 2 7 Water absorption 287％ 303％ 355％ 212％

[0072] (3) Anti-rust and emulsification properties: The anti-rust oil was prepared according to the formula shown in Table 3, and the salt spray time and storage stability were examined. The salt spray time test was carried out in accordance with the industry standard SH / T 0081-91 "Salt spray test method for anti-rust greases". The storage stability test method is: put the prepared anti-rust oil into an oven at 50°C and observe it visually every 24 hours until an insoluble precipitate appears at the bottom of the bottle.

[0073] Table 3

[0074]

[0075] The test results are shown in Table 4 below: Group 1 does not add an emulsifier, Group 2 adds commercially available lanolin as an emulsifier, and Groups 3-5 add the emulsifiers of Examples 1-3, respectively. It can be seen that the salt spray time of the rust-proof oil added with the examples is equivalent to or better than the rust-proof oil added with lanolin; the storage stability of the rust-proof oil added with the examples is better than the rust-proof oil without or with lanolin.

[0076] Table 4

[0077] Group Salt spray time / h Storage stability / d 1 72 15 2 80 22 3 80 27 4 96 28 5 88 35

[0078] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0079] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for preparing synthetic lanolin, characterized in that: The steps include: 1) adding polyols, various monobasic fatty acid methyl esters, antioxidants, and transesterification catalysts into a reaction kettle, heating the reaction kettle under stirring and vacuum conditions, and performing transesterification reaction until the acid value of the product is less than 1 mgKOH / g; 2) adding one or more dibasic acids and an esterification catalyst, heating under stirring and vacuum conditions, and performing an esterification reaction until the acid value of the product is less than 1 mgKOH / g; 3) After cooling, the product is subjected to decolorization, washing, deodorization and dehydration treatment to obtain the finished synthetic lanolin product.

2. The method for preparing synthetic lanolin according to claim 1, characterized in that: The reaction temperature of step 1) is 120-150° C., and the reaction time is 4-12 hours; the molar ratio of the polyol to the monobasic fatty acid methyl ester is 1:(1.5-4.5).

3. The method for preparing synthetic lanolin according to claim 1, characterized in that: The reaction temperature of step 2) is 150-180° C., and the reaction time is 4-12 hours; the molar ratio of the dibasic acid to the polyol is (0.5-0.9):

1.

4. The method for preparing synthetic lanolin according to claim 1, characterized in that: The reactions of step 1) and step 2) are both carried out under a vacuum degree greater than -0.095 MPa.

5. The method for preparing synthetic lanolin according to claim 1, characterized in that: The polyol is at least one of glycerol, diglycerol, triglycerol, tetraglycerol, pentaglycerol and hexaglycerol; the dibasic acid is at least one of succinic acid, adipic acid, sebacic acid and dimer acid; the monobasic fatty acid methyl ester is a mixture of multiple components of methyl caprylate, methyl laurate, methyl myristic acid, methyl palmitate, methyl stearate, methyl 12-hydroxystearate and methyl isostearate.

6. The method for preparing synthetic lanolin according to claim 1, characterized in that: The antioxidant is one or a mixture of two or more of butylated hydroxyanisole, butylated hydroxytoluene, 2,5-di-tert-butylhydroquinone, propyl gallate, vitamin E, and tert-butylhydroquinone, and its dosage is 0.02%-0.2% of the total mass of the reaction raw materials.

7. The method for preparing synthetic lanolin according to claim 1, characterized in that: The transesterification catalyst is at least one of potassium hydroxide, sodium hydroxide, tetrabutyl titanate and tetraisopropyl titanate, and its usage is 0.02%-0.05% of the total mass of the reaction raw materials.

8. The method for preparing synthetic lanolin according to claim 1, characterized in that: In step 3), the temperature is lowered to 120-150°C for decolorization and lowered to 80°C for washing.

9. The method for preparing synthetic lanolin according to claim 1, characterized in that: The decolorizing agent used in the decolorizing process is hydrogen peroxide; the washing process is first washed with alkali solution and then washed with distilled water, and the concentration of the alkali solution is 1%-15%; the deodorizing process adopts steam deodorization, the steam temperature is 150-160℃, and the deodorizing time is 0.5-2h.

10. A synthetic lanolin, characterized in that It is prepared by the preparation method described in any one of claims 1 to 9; the structure of the synthetic lanolin is shown in formula (I): In the structural formula (I), R3 represents the residue after dibasic acid esterification, R4 represents the residue after polyol reaction, and R5 and R6 represent the residue after monobasic fatty acid methyl ester undergoes ester exchange reaction.

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