Heat-resistant polyester polyol and preparation method and application thereof

Abstract

The application provides a heat-resistant polyester polyol and a preparation method and application thereof. The polyester polyol contains a piperazine structure, and a cyclic structure effectively improves mechanical properties of the product, simultaneously improves cohesive energy in a soft segment and crosslinking density of a molecular chain segment, and a polyurethane product prepared from the polyester polyol has excellent heat resistance.

Description

Technical Field

[0001] This invention belongs to the field of polyester polyols, specifically relating to a heat-resistant polyester polyol, its preparation method, and its application. Background Technology

[0002] As a typical polymer material, thermoplastic polyurethane has excellent elasticity and flexibility, superior resilience and fatigue life. It is easily processed into various shapes and sizes and can be recycled and reprocessed, making it widely used in hoses, cables, films, and other applications.

[0003] Compared with thermosetting polyurethane, thermoplastic polyurethane has poor heat resistance. Its long-term operating temperature is no higher than 80℃. When used in high-temperature environments, the shape of its products will change significantly, and physical properties such as hardness, surface properties, tensile strength, and modulus will also change, rendering it unusable. Insufficient heat resistance affects its application, especially in the field of outdoor cables.

[0004] To address the aforementioned issues, a novel heat-resistant polyester polyol needs to be developed to solve these technical problems. Summary of the Invention

[0005] To address the above technical problems, one objective of this invention is to provide a polyester polyol that effectively improves the mechanical properties of products, while the polyurethane products made from it have excellent heat resistance.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0007] A polyester polyol, the structure of which is shown in Formula 1:

[0008]

[0009] Where R1, R2, and R independently represent C2-C 10 One or more of the alkyl groups, preferably -C3H6-, straight-chain or branched -C4H8-, straight-chain or branched -C6H 12 - one or more of the following, R3 and R4 represent C2-C 10 One or more of alkylene oxides and alkylene amines, preferably one or more of -C2H4O, -C3H6O-, -C2H4NH-, and -C3H6NH-; X is an integer from 5 to 20, preferably an integer from 8 to 16; Y is an integer from 1 to 5, preferably an integer from 2 to 4.

[0010] The polyol in the application contains a piperazine structure, and the cyclic structure effectively improves the mechanical properties of the product. Meanwhile, the piperazine structure forms intermolecular hydrogen bonds with ester groups and carbamate groups, thereby improving the cohesive energy in the soft segment and the crosslinking density of the molecular segment. The polyurethane product prepared therefrom has excellent heat resistance.

[0011] Another object of the application is to provide a method for preparing a polyester polyol.

[0012] A method for preparing the polyester polyol described above, the method comprising the following steps:

[0013] The piperazine structure-containing raw material is subjected to esterification and polycondensation reaction with a dibasic acid and a dibasic alcohol to prepare the polyester polyol containing the piperazine structure.

[0014] In an embodiment of the application, the end group of the piperazine structure-containing raw material is one or more of a hydroxyl group, an amino group and a carboxyl group, preferably one or more of 1,4-bis(2-hydroxyethyl)piperazine, 1,4-piperazine diethylamine, 2-(4-(2-aminoethyl)piperazin-1-yl)ethanol, 1,4-bis(3-aminopropyl)piperazine, 1,4-bis(2-carboxyethyl)piperazine, 1-amino 4-(2-hydroxyethyl)piperazine, 3-[4-(2-hydroxy-ethyl)-piperazin-1-yl]-1-propanol, 3-[4-(2-hydroxyethyl)piperazin-1-yl]-propanoic acid, [4-(2-hydroxy-ethyl)-piperazin-1-yl]-acetic acid.

[0015] In an embodiment of the application, the dibasic acid is a C4-C10 saturated dibasic acid, preferably one or more of succinic acid, adipic acid, glutaric acid, sebacic acid and azelaic acid.

[0016] In an embodiment of the application, the dibasic alcohol is a C2-C8 dibasic alcohol, preferably one or more of ethylene glycol, 1,4-butanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, 2-methyl-1,3-propanediol, 1,5-pentanediol and 1,6-hexanediol; preferably, the mass ratio of the piperazine structure-containing raw material to the dibasic alcohol is 0.05-0.5:1, preferably 0.1-0.3:1; preferably, the mass ratio of the dibasic acid to the dibasic alcohol is 0.78-0.98:1, preferably 0.85-0.95:1.

[0017] In one embodiment of the present application, the esterification polycondensation reaction comprises a normal pressure stage and a vacuum stage; preferably, the normal pressure stage of the esterification polycondensation reaction has a reaction temperature of 150-220°C, preferably 160-210°C, and a reaction time of 4-24h, preferably 8-18h; preferably, the vacuum stage of the esterification polycondensation reaction has a reaction temperature of 220-250°C, preferably 230-240°C, a reaction pressure of 0.1-8kPa, preferably 1-5kPa, and a reaction time of 4-20h, preferably 6-16h.

[0018] It is still another object of the present application to provide a use of the polyester polyol.

[0019] A use of the polyester polyol, which is the polyester polyol as described above or prepared by the method as described above, for preparing a thermoplastic polyurethane having heat resistance and high mechanical properties.

[0020] It is still another object of the present application to provide a thermoplastic polyurethane.

[0021] A thermoplastic polyurethane prepared by using the polyester polyol as described above or prepared by the method as described above.

[0022] It is still another object of the present application to provide a use of the thermoplastic polyurethane.

[0023] A use of the thermoplastic polyurethane prepared by using the polyester polyol as described above or prepared by the method as described above, for preparing electric wires and cables, hoses, films.

[0024] Compared with the prior art, the present application has the following advantages:

[0025] (1) The heat resistance of the thermoplastic polyurethane is improved.

[0026] (2) The mechanical properties of the polyurethane are effectively improved.

[0027] (3) The polyester polyol contains a tertiary amine structure, and no catalyst is needed for the synthesis of the polyol and the preparation of the polyurethane, and there is no risk of organic metal residues being released from the product, which is safe and environmentally friendly. DETAILED DESCRIPTION

[0028] The present application will be further described below by means of specific examples, which are only used to illustrate the present application and do not limit the scope of the present application.

[0029] The chemical reagents used in the method of the present application are all conventional reagents in the art, and have a purity of more than chemical purity.

[0030] 1,4-Bis(2-hydroxyethyl)piperazine, Aladdin, 98% purity;

[0031] 3-[4-(2-hydroxy-ethyl)-piperazin-1-yl]-1-propanol, Aladdin, 98% purity;

[0032] 1,4-Piperazine diethylamine, Aladdin, 95% purity;

[0033] 2-(4-(2-aminoethyl)piperazin-1-yl)ethanol, Aladdin, purity 96%;

[0034] 1,4-Bis(3-aminopropyl)piperazine, Aladdin, 96% purity.

[0035] The selected equipment is a 1L batch reactor with a distillation column.

[0036] Nuclear magnetic resonance spectroscopy (NMR) 13 C NMR analysis: The ANAVCE 500 NMR analyzer manufactured by Bruker GmbH, Germany, was used, with CDCl3 as the solvent.

[0037] Tensile testing was performed according to ASTM D412, tear strength according to ASTM D624, and tensile speed was 500 mm / min; Vicat softening point testing was performed according to ASTM D1525.

[0038] Example 1

[0039] Under nitrogen protection, 22g of 1,4-bis(2-hydroxyethyl)piperazine, 187g of adipic acid, and 220g of ethylene glycol were fed into a polyester reactor. The reactor was gradually heated to 160℃ and esterified under normal pressure for 18 hours. Then, the reaction pressure was reduced to 1kPa(A), the temperature was raised to 230℃, and the reaction was carried out under vacuum for 6 hours. The product was then cooled and discharged to obtain the target polyester polyol product.

[0040] The qualitative characterization results of the product are as follows: 13 C NMR (CDCl3, 100MHz), δppm, 24.4, 33.6, 54.2, 57.9, 61.1, 62.1, 64.1, 173.1.

[0041] Example 2

[0042] Under nitrogen protection, 45g of 3-[4-(2-hydroxy-ethyl)-piperazin-1-yl]-1-propanol, 200g of succinic acid, 62.5g of glutaric acid, and 300g of 1,4-butanediol were fed into a polyester reactor. The reactor was gradually heated to 170℃ and esterified under normal pressure for 16 hours. Then, the reaction pressure was reduced to 2.5kPa(A), the temperature was raised to 235℃, and the reaction was carried out under vacuum for 8 hours. The product was then cooled and discharged to obtain the target polyester polyol product.

[0043] Example 3

[0044] Under nitrogen protection, 34g of 1,4-piperazine diethylamine, 153g of glutaric acid, and 170g of 1,5-pentanediol were fed into a polyester reactor. The reactor was gradually heated to 180℃ and esterified under normal pressure for 14 hours. Then, the reaction pressure was reduced to 3kPa(A), the temperature was raised to 235℃, and the reaction was carried out under vacuum for 10 hours. The product was then cooled and discharged to obtain the target polyester polyol product.

[0045] Example 4

[0046] Under nitrogen protection, 137.5g of 2-(4-(2-aminoethyl)piperazin-1-yl)ethanol, 508.7g of sebacic acid, and 550g of 2-methyl-1,3-propanediol were fed into a polyester reactor. The reactor was gradually heated to 190℃ and esterified under normal pressure for 16 hours. Then, the reaction pressure was reduced to 5kPa(A), the temperature was raised to 240℃, and the reaction was carried out under vacuum for 16 hours. The product was then cooled and discharged to obtain the target polyester polyol product.

[0047] Example 5

[0048] Under nitrogen protection, 72g of 1,4-bis(3-aminopropyl)piperazine, 228g of azelaic acid, and 240g of 1,4-butanediol were fed into a polyester reactor. The reactor was gradually heated to 210℃ and esterified under normal pressure for 16 hours. Then, the reaction pressure was reduced to 5kPa(A), the temperature was raised to 240℃, and the reaction was carried out under vacuum for 11 hours. The product was then cooled and discharged to obtain the target polyester polyol product.

[0049] Comparative Example 1

[0050] Compared with Example 1, the difference is that no piperazine-containing raw material is added.

[0051] Under nitrogen protection, 187g of adipic acid and 220g of ethylene glycol were fed into a polyester reactor. The reactor was gradually heated to 160℃ and esterified at atmospheric pressure for 18 hours. Then, the reaction pressure was reduced to 1kPa(A), the temperature was raised to 230℃, and the reaction was carried out under vacuum for 6 hours. The product was then cooled and discharged to obtain the target polyester polyol product.

[0052] The polyester polyols prepared in the above examples and comparative examples were mixed in the following proportions: polyester polyol: 55 parts, BDO: 10 parts, MDI isocyanate: 35 parts. After stirring and heating to 100°C, the mixture was poured into a mold and cured at 100°C for 10 hours. After crushing, the mixture was injection molded into test pieces at 220°C. The test pieces were then placed in a 95°C oven and left to stand for 12 hours to obtain thermoplastic polyurethane samples.

[0053] The mechanical and heat resistance properties of the series of thermoplastic polyurethane products prepared above were tested, and the results are shown in the table below.

[0054] Table 1. Performance test results of polyurethane

[0055]

[0056]

[0057] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A polyester polyol, characterized in that, The structure of the polyol is shown in Formula 1: Formula 1 Wherein, R1, R2, and R independently represent one or more of C2-C10 alkyl groups, R3 and R4 represent one or more of C2-C10 alkylene oxides and alkylene amines; X is an integer from 5 to 20; and Y is an integer from 1 to 5.

2. The polyester polyol according to claim 1, characterized in that, R1, R2, and R are independently selected from one or more of -C3H6-, straight or branched -C4H8-, and straight or branched -C6H12-; R3 and R4 are selected from one or more of -C2H4O, -C3H6O-, -C2H4NH-, and -C3H6NH-; X is an integer from 8 to 16; and Y is an integer from 2 to 4.

3. A method for preparing the polyester polyol according to claim 1 or 2, characterized in that, The method includes the following steps: Piperazine-containing raw materials are subjected to esterification and polycondensation reactions with dibasic acids and diols to prepare polyester polyols containing piperazine structures.

4. The method according to claim 3, characterized in that, The end group of the piperazine-containing raw material is one or more of hydroxyl and amino groups; And / or, the dicarboxylic acid is a saturated dicarboxylic acid of C4-C10; And / or, the diol is a C2-C8 diol.

5. The method according to claim 4, characterized in that, The piperazine-containing raw material is selected from one or more of 1,4-bis(2-hydroxyethyl)piperazine, 1,4-piperazine diethylamine, 2-(4-(2-aminoethyl)piperazin-1-yl)ethanol, 1,4-bis(3-aminopropyl)piperazine, 1-amino4-(2-hydroxyethyl)piperazine, and 3-[4-(2-hydroxy-ethyl)-piperazin-1-yl]-1-propanol; And / or, the dicarboxylic acid is one or more of succinic acid, adipic acid, glutaric acid, sebacic acid, and azelaic acid; And / or, the diol is one or more of ethylene glycol, 1,4-butanediol, 3-methyl-1,5-pentanediol, neopentanediol, 1,4-cyclohexanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, and 2-methyl-2,4-pentanediol; The mass ratio of piperazine-containing raw material to diol is 0.05~0.5:1; The mass ratio of dicarboxylic acid to diol is 0.78~0.98:

1.

6. The method according to claim 5, characterized in that, The mass ratio of piperazine-containing raw materials to diols is 0.1~0.3:1; The mass ratio of dicarboxylic acid to diol is 0.85~0.95:

1.

7. The preparation method according to claim 3, characterized in that, The esterification polycondensation reaction includes an atmospheric pressure stage and a vacuum stage.

8. The preparation method according to claim 7, characterized in that, The esterification polycondensation reaction is carried out at atmospheric pressure, with a reaction temperature of 150~220℃ and a reaction time of 4~24h. The vacuum stage of the esterification polycondensation reaction is characterized by a reaction temperature of 220~250℃, a reaction pressure of 0.1~8kPa absolute, and a reaction time of 4~20h.

9. The preparation method according to claim 8, characterized in that, The esterification polycondensation reaction is carried out at atmospheric pressure at a temperature of 160-210℃ for 8-18 hours. The vacuum stage of the esterification polycondensation reaction is characterized by a reaction temperature of 230-240℃, a reaction pressure of 1-5 kPa absolute, and a reaction time of 6-16 h.

10. Use of a polyester polyol, wherein the polyester polyol is the polyester polyol according to claim 1 or 2, or the polyester polyol prepared by the method according to any one of claims 3-9, wherein the polyester polyol is used to prepare thermoplastic polyurethane with heat resistance and high mechanical properties.

11. A thermoplastic polyurethane, wherein the thermoplastic polyurethane is prepared using the polyester polyol of claim 1 or 2, or using the polyester polyol prepared by any one of claims 3-9.

12. A use of a thermoplastic polyurethane, wherein the thermoplastic polyurethane is prepared using the polyester polyol of claim 1 or 2, or the polyester polyol prepared by any one of claims 3-9, and the thermoplastic polyurethane is used to prepare wires and cables, hoses, and films.

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