Preparation method of bio-based diamide bicyclic carbonate and amide type non-isocyanate polyurethane

Abstract

The invention discloses a preparation method of bio-based diamide bicyclic carbonate and amide type non-isocyanate polyurethane, and belongs to the technical field of polyurethane. The method comprises the following steps: firstly, reacting bio-based dibasic acid or ester with 3-amino-1, 2-propylene glycol to obtain diamidotetrol, and then reacting with carbonic acid diester in the presence of a catalyst and a phase transfer agent to synthesize bio-based diamide bicyclic carbonate; further, dimethyl itaconate and aliphatic diamine are subjected to condensation polymerization to synthesize amino-terminated itaconic acid polyamide, the amino-terminated itaconic acid polyamide reacts with diamide bicyclic carbonate under the conditions of no catalyst and no solvent, and amide type bio-based non-isocyanate polyurethane is synthesized. The method is based on the bio-based dibasic acid, the diamine and the glycerol derivative 3-aminopropanediol which are rich in source and low in price, the preparation process is green and environment-friendly, the operation is simple and convenient, and the prepared amide type non-isocyanate polyurethane is excellent in mechanical property.

Description

Technical Field

[0001] The present invention relates to a new method for synthesizing a bio-based diamide bicyclic carbonate, which is reacted with an amino-terminated itaconic acid polyamide to synthesize an amide-type non-isocyanate polyurethane. The specific content is as follows: A bio-based dicarboxylic acid or ester is reacted with 3-amino-1,2-propanediol to obtain a diamide tetrol, and then it is reacted with a carbonate diester in the presence of a catalyst and a phase transfer agent to synthesize a bio-based diamide bicyclic carbonate; further, an amino-terminated itaconic acid polyamide synthesized by polycondensing dimethyl itaconate with an excessive aliphatic diamine is reacted with the bio-based diamide bicyclic carbonate under the conditions of no catalyst and no solvent to synthesize an amide-type bio-based non-isocyanate polyurethane. This method belongs to the technical field of polyurethanes. Technical Background

[0002] Traditional polyurethanes (PUs) are often synthesized using diisocyanate monomers, and diisocyanates are toxic. Their production, use, and residues in the final products can cause harm to the environment and the human body. With the increasing awareness of environmental protection, people have paid more and more attention to the research and development of green and environmentally friendly non-isocyanate polyurethanes (NIPUs).

[0003] Currently, the preparation of NIPUs mainly includes two methods: the cyclic carbonate method and the urethane exchange method. Among them, the research on polyhydroxy polyurethanes (PHUs) prepared by the ammonolysis of cyclic carbonates with polyamines has received the most attention. Compared with traditional polyurethanes, PHUs molecules contain many side hydroxyl groups, which are easy to form intermolecular and intramolecular hydrogen bonds with urethane groups, which is beneficial to improving the solvent resistance and chemical corrosion resistance of the materials.

[0004] Currently, linear and crosslinked PHUs can be prepared by reacting bicyclic carbonates with aliphatic or cycloaliphatic polyamines. However, because this method is prone to side reactions, generating non-reactive urea bonds, oxazolidinones, and alcohol structures, the molecular weight of linear PHUs is relatively low and the performance is poor. Crosslinked PHUs also often have poor mechanical properties due to their low glass transition temperature and lack of hard phase structures such as crystallization, making it difficult to meet actual needs. In addition, most of the currently used binary or polycyclic carbonate monomers are synthesized by the cyclic carbonation of epoxy resins with CO2 under high temperature and high pressure, which requires high equipment and process requirements; high-boiling solvents are often needed to dissolve reactants and products, and the separation of products is relatively complex, resulting in a high preparation cost of cyclic carbonate monomers, which limits the popularization and application of this method.

[0005] The present invention provides a new method for preparing biobased diamide bicyclic carbonate simply and efficiently, and synthesizes amide-based biobased non-isocyanate polyurethane by reacting with amino-terminated itaconic acid polyamide. First, a biobased dicarboxylic acid or ester is reacted with 3-amino-1,2-propanediol to obtain diamide tetrol, and then it is reacted with a carbonic acid diester in the presence of a catalyst and a phase transfer agent to synthesize diamide bicyclic carbonate; furthermore, an amino-terminated itaconic acid polyamide synthesized by polycondensing dimethyl itaconate and an aliphatic diamine is reacted with the biobased diamide bicyclic carbonate under catalyst-free and solvent-free conditions to synthesize amide-based biobased non-isocyanate polyurethane. Summary of the Invention

[0006] The object of the present invention is to overcome the deficiencies in the prior art and provide a method for synthesizing a diamide bicyclic carbonate monomer by the cyclic carbonatation of biobased diamide tetrol, and preparing amide-based biobased non-isocyanate polyurethane by reacting with amino-terminated itaconic acid polyamide. The reaction method has easily available raw materials, simple operation, and the prepared non-isocyanate polyurethane has excellent properties.

[0007] In the present invention, a biobased dicarboxylic acid or ester is first reacted with 3-amino-1,2-propanediol to obtain diamide tetrol, and then it is reacted with a carbonic acid diester in the presence of a catalyst and a phase transfer agent to synthesize diamide bicyclic carbonate; furthermore, an amino-terminated itaconic acid polyamide synthesized by polycondensing dimethyl itaconate and an excessive aliphatic diamine is reacted with the diamide bicyclic carbonate under catalyst-free and solvent-free conditions to synthesize non-isocyanate polyurethane. The specific steps are as follows:

[0008] 1) Preparation of biobased diamide tetrol: Under a nitrogen atmosphere, the biobased dicarboxylic acid or ester and 3-amino-1,2-propanediol are fed in a molar ratio of 1:2, stirred and reacted at 80-150 °C for 6 h, distilled for 4 h, and the biobased diamide tetrol is obtained after recrystallization;

[0009] 2) Preparation of biobased diamide bicyclic carbonate: The diamide tetrol and the carbonic acid diester are fed in an equivalent ratio of 1:(6-10), a small amount of carbonate catalyst and a phase transfer agent are added, and the reaction is carried out at 70-120 °C for 12-24 h. The diamide bicyclic carbonate monomer powder is obtained after recrystallization.

[0010] 3) Preparation of biobased amino-terminated itaconic acid polyamide: Dimethyl itaconate and an aliphatic diamine are mixed in a molar ratio of n:(n + 1) (n = 2, 3, 5 or 7), and under a nitrogen atmosphere, the reaction is stirred at 80-150 °C for 5 h, distilled for 4 h, and vacuum distilled for 2 h to obtain biobased amino-terminated itaconic acid polyamide;

[0011] 4) Preparation of amide - type non - isocyanate polyurethane: Mix the amino - terminated itaconic acid polyamide obtained in step 3) and the bio - based diamide bicyclic carbonate obtained in step 2) in a molar ratio of 1:1. Under a nitrogen atmosphere, stir and react at 60 - 150 °C for 7 h to obtain an amide - type bio - based non - isocyanate polyurethane material.

[0012] Among them, the bio - based diamide tetrol obtained in step 1) has a structure as shown in (Ⅰ):

[0013]

[0014] where m is between 0 and 16.

[0015] The structure of the bio - based diamide bicyclic carbonate synthesized in step 2) is as shown in (II):

[0016]

[0017] where m is between 0 and 16.

[0018] The general formula of the amino - terminated itaconic acid polyamide obtained in step 3) is as shown in (III):

[0019]

[0020] where n is 2, 3, 5 or 7, etc., R is (CH2) p , p = 2 - 12.

[0021] The general formula structure of the amide - type non - isocyanate polyurethane obtained in step 4) is as shown in (IV):

[0022]

[0023] where m is between 0 and 16; H2N - R 1 -NH2 is the amino - terminated itaconic acid polyamide, R is (CH2) p , p = 2 - 12; n = 2, 3, 5 or 7, etc. r is the number of repeating units.

[0024] Furthermore, the bio - based dibasic acid used in step 1) is one or more of oxalic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, etc., and its esters are dimethyl ester, diethyl ester, dipropyl ester, etc.

[0025] The carbonate catalysts used in step 2) are one or more of lithium carbonate, sodium carbonate, potassium carbonate, lithium bicarbonate, sodium bicarbonate, potassium bicarbonate; the phase transfer agents used are tetrabutylammonium bromide, trimethylbenzylammonium chloride, etc.; the carbonic acid diesters used are one or more of dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, etc.

[0026] The aliphatic diamine used in step 3) is one or more of ethylenediamine, butanediamine, pentanediamine, hexanediamine, decanediamine, undecanediamine, dodecanediamine, etc.

[0027] Advantages of the present invention:

[0028] The present invention synthesizes bio-based diamide bicyclic carbonate by the reaction of diamide tetrol and dicarbonate, and then synthesizes amide-type non-isocyanate polyurethane by reacting with amino-terminated itaconic acid polyamide.

[0029] This method is simple, efficient, environmentally friendly, and introduces many amide structures into polyhydroxy urethanes (PHUs), resulting in excellent mechanical properties of the prepared non-isocyanate polyurethane. The tensile strength can reach 22 MPa, and the elongation at break can reach 329%. Description of the drawings

[0030] Figure 1 1H-NMR spectrum of 1 hexanediamide bicyclic carbonate

[0031] Figure 2 1H-NMR spectrum of 1 L-NIPU-4:3. Specific embodiments

[0032] According to the standard of GB / T 1040—2006, the product is made into a standard dumbbell-shaped specimen with a tensile speed of 5 mm / min, and its tensile strength and elongation at break are measured by an INSTRON-1185 universal tensile machine.

[0033] According to the above-described embodiments, the following are preferred examples for detailed description of the present invention, but the implementation of the present invention is not limited to the following examples.

[0034] Example 1:

[0035] 1) Preparation of bio-based hexanediamide tetrol: Under a nitrogen atmosphere, 69.42 parts by weight of 3-amino-1,2-propanediol are weighed and 64.75 parts by weight of dimethyl adipate are added. The temperature is raised to 120 °C and stirred for 6 h, then distilled for 4 h, and the product is recrystallized to obtain 67.68 parts by weight of white hexanediamide tetrol (where the corresponding m is 6) powder. The yield is 92.52%, and its melting point is 123 °C.

[0036] 2) Preparation of biobased hexamethylenediamide bicyclic carbonate: 20 parts of hexamethylenediamide tetrol obtained in step 1) of Example 1, 96.51 parts of ethylene carbonate, 0.22 parts of anhydrous potassium carbonate, and 0.06 parts of tetrabutylammonium bromide were mixed and refluxed at 70 °C for 24 h to end the reaction. Recrystallization was carried out to finally obtain 27.62 parts of hexamethylenediamide bicyclic carbonate with a yield of 59.14%, a melting point of 152 °C, and its NMR spectrum is shown in Figure 1 .

[0037] 3) Amino-terminated itaconic acid polyamide DDMI-3:2: 10 parts of dimethyl itaconate were weighed by weight, 16.329 parts of decanediamine were added, and under a nitrogen atmosphere, the temperature was raised to 140 °C and stirred for 5 h, distilled for 4 h, and vacuum distilled for 2 h to stop the reaction, obtaining amino-terminated itaconic acid polyamide DDMI-3:2 (p is 10) with a molecular weight of 704 g / mol.

[0038] 4) Amide-based non-isocyanate polyurethane: 2.932 parts of the diamide bicyclic carbonate obtained in step 2) were weighed by weight and mixed with 6 parts of the amino-terminated itaconic acid polyamide DDMI-3:2 obtained in step 3). Under a nitrogen atmosphere, the mixture was stirred at 120 °C for 7 h to stop the reaction, obtaining amide-based non-isocyanate polyurethane L-NIPU-3:2 with a tensile strength of 21 MPa and an elongation at break of 274%.

[0039] Example 2:

[0040] 1) Amino-terminated itaconic acid polyamide DDMI-4:3: 10 parts of dimethyl itaconate were weighed by weight, 14.515 parts of decanediamine were added, and under a nitrogen atmosphere, the temperature was raised to 140 °C and stirred for 5 h, distilled for 4 h, and vacuum distilled for 2 h to stop the reaction, obtaining amino-terminated itaconic acid polyamide DDMI-4:3 with a molecular weight of 970 g / mol.

[0041] 2) Amide-based non-isocyanate polyurethane: 2.128 parts of the diamide bicyclic carbonate obtained in step 2) of Example 1 were weighed by weight and mixed with 6 parts of the amino-terminated itaconic acid polyamide obtained in step 1) of Example 2. Under a nitrogen atmosphere, the mixture was stirred at 120 °C for 7 h to stop the reaction, obtaining amide-based non-isocyanate polyurethane L-NIPU-4:3 with a tensile strength of 22 MPa and an elongation at break of 289%, and its NMR spectrum is shown in Figure 2 .

[0042] Example 3:

[0043] 1) Polyamide of amino-terminated itaconic acid DDMI-6:5: Weigh 10 parts of dimethyl itaconate by weight, add 13.063 parts of sebac diamine, under nitrogen atmosphere, heat up to 140 °C and stir for reaction for 5 h, distill for 4 h, and carry out vacuum distillation for 2 h, then stop the reaction to obtain polyamide of amino-terminated itaconic acid DDMI-6:5, whose molecular weight is 1502 g / mol.

[0044] 2) Amide-type non-isocyanate polyurethane: Weigh 1.374 parts of the diamide bicyclic carbonate obtained in step 2) of Example 1 by weight, mix it with 6 parts of the polyamide of amino-terminated itaconic acid obtained in step 1) of Example 3, under nitrogen atmosphere, stir at 120 °C for reaction for 7 h, then stop the reaction to obtain amide-type non-isocyanate polyurethane L-NIPU-6:5, whose tensile strength is 21 MPa and elongation at break is 270%.

[0045] Example 4:

[0046] 1) Polyamide of amino-terminated itaconic acid DDMI-8:7: Weigh 10 parts of dimethyl itaconate by weight, add 12.441 parts of sebac diamine, under nitrogen atmosphere, heat up to 140 °C and stir for reaction for 5 h, distill for 4 h, and carry out vacuum distillation for 2 h, then stop the reaction to obtain polyamide of amino-terminated itaconic acid DDMI-8:7, whose molecular weight is 2034 g / mol.

[0047] 2) Amide-type non-isocyanate polyurethane: Weigh 1.015 parts of the diamide bicyclic carbonate obtained in step 2) of Example 1 by weight, mix it with 6 parts of the polyamide of amino-terminated itaconic acid obtained in step 1) of Example 4, under nitrogen atmosphere, stir at 120 °C for reaction for 7 h, then stop the reaction to obtain amide-type non-isocyanate polyurethane L-NIPU-8:7, whose tensile strength is 21 MPa and elongation at break is 329%.

Claims

1. Preparation method of bio-based diamide bicyclic carbonate and amide-based non-isocyanate polyurethane, characterized in that, Firstly, a diamide tetrol is synthesized by reacting a biobased aliphatic dicarboxylic acid or ester with aminopropanediol, and then a diamide bicyclic carbonate monomer is synthesized by reacting with a small molecule carbonate. By reacting with different polyamides with terminal amino itaconic acid, the structures of the dicarboxylic acid and the polyamide with terminal amino itaconic acid are adjusted to obtain non-isocyanate polyurethanes (PAHUs) with amide bonds, excellent mechanical properties and flexibility. The specific steps are as follows: 1) Preparation of biobased diamide tetrol: In a nitrogen atmosphere, a biobased dicarboxylic acid or ester and 3-amino-1,2-propanediol are fed in a molar ratio of 1:2, stirred and reacted at 80-150 °C for 6 h, distilled for 4 h, and the biobased diamide tetrol is obtained after recrystallization; 2) Preparation of biobased diamide bicyclic carbonate: The biobased diamide tetrol and a carbonic acid diester are fed in an equivalent ratio of 1:(6-10), a small amount of carbonate catalyst and a phase transfer agent are added, and the reaction is carried out at 70-120 °C for 12-24 h. The diamide bicyclic carbonate monomer powder is obtained after recrystallization; 3) Preparation of polyamide with terminal amino itaconic acid: Dimethyl itaconate and an aliphatic diamine are mixed in a molar ratio of n:(n + 1), where n = 2, 3, 5 or 7, stirred and reacted at 80-150 °C for 5 h, distilled for 4 h, and vacuum distilled for 2 h to obtain a biobased polyamide with terminal amino itaconic acid; 4) Preparation of amide-based biobased non-isocyanate polyurethane: The polyamide with terminal amino itaconic acid obtained in step 3) and the biobased diamide bicyclic carbonate obtained in step 2) are mixed in a molar ratio of 1:1, and stirred and reacted at 60-150 °C for 7 h in a nitrogen atmosphere to obtain an amide-based non-isocyanate polyurethane material.

2. The method according to claim 1, wherein In step 1), the biobased diamide tetrol is synthesized, and its structure is as shown in (Ⅰ): where m is 0-16; In step 2), the biobased diamide bicyclic carbonate synthesized has a structure as shown in (II): where m is 0-16; In step 3), the biobased polyamide with terminal amino itaconic acid obtained has a structure as shown in (III): where n is 2, 3, 5, 7, etc., and R is (CH2) p , and p = 2 to 12; In step 4), the amide-based biobased non-isocyanate polyurethane obtained has a structure as shown in (IV): where m is between 0 and 16; H2N-R 1 -NH2 is an amino-terminated itaconic acid polyamide, and R is (CH2) p , p = 2 to 12; n = 2, 3, 5 or 7, etc., and r is the number of repeating units.

3. The method according to claim 1, wherein The biobased dicarboxylic acid used in step 1) is one or more of oxalic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, etc., and its ester is dimethyl ester, diethyl ester, dipropyl ester, etc.

4. The method according to claim 1, characterized in that The carbonate catalyst used in step 2) is one or more of lithium carbonate, sodium carbonate, potassium carbonate, lithium bicarbonate, sodium bicarbonate, potassium bicarbonate, etc.; the phase transfer agent used is tetrabutylammonium bromide, trimethylbenzylammonium chloride, etc.; the carbonic acid diester used is one or more of dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, etc.

5. The method according to claim 1, characterized in that, The aliphatic diamine used in step 3) is one or more of ethylenediamine, butanediamine, pentanediamine, hexanediamine, decanediamine, undecanediamine, dodecanediamine, etc.

6. A non-isocyanate polyurethane prepared by the method according to any one of claims 1-5.

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