Heat-resistant polyester polyol as well as preparation method and application thereof

Abstract

The invention provides heat-resistant polyester polyol as well as a preparation method and application thereof. The polyester polyol contains a piperazine structure and a cyclic structure, so that the mechanical property of a product is effectively improved, meanwhile, the cohesive energy of a soft segment and the crosslinking density of a molecular chain segment are improved, and a polyurethane product prepared from the polyester polyol has excellent heat resistance.

Description

Technical Field

[0001] The invention belongs to the field of polyester polyols, and specifically relates to a heat-resistant polyester polyol and a preparation method and application thereof. Background Art

[0002] As a typical polymer material, thermoplastic polyurethane has very good elasticity and flexibility, excellent resilience and fatigue life, is easy to process into various shapes and sizes, and can be recycled and repeatedly processed. It is widely used in hoses, cables, films, etc.

[0003] Compared with thermosetting polyurethane, thermoplastic polyurethane has poor heat resistance. The long-term use temperature is not higher than 80°C. When used in a high temperature environment, the shape of the product will change significantly, and physical indicators such as hardness, surface properties, tensile strength, and modulus will also change and lose its application value. Insufficient heat resistance affects its application, especially in the field of outdoor cables.

[0004] In view of the above problems, it is necessary to develop a new type of heat-resistant polyester polyol to solve the above technical problems. Summary of the invention

[0005] In order to solve the above technical problems, one of the purposes of the present invention is to provide a polyester polyol, which effectively improves the mechanical properties of the product, and the polyurethane product prepared therefrom has excellent heat resistance.

[0006] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is as follows:

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

[0008]

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

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

[0011] Another object of the present invention is to provide a method for preparing polyester polyols.

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

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

[0014] In one embodiment of the present invention, the end group of the raw material containing piperazine structure is one or more of hydroxyl, amino and carboxyl groups, preferably one or more of 1,4-bis(2-hydroxyethyl)piperazine, 1,4-piperazine diethylamine, 2-(4-(2-aminoethyl)piperazine-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)-piperazine-1-yl]-1-propanol, 3-[4-(2-hydroxyethyl)piperazine-1-yl]-propionic acid and [4-(2-hydroxy-ethyl)-piperazine-1-yl]-acetic acid.

[0015] In one embodiment of the present invention, 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 one embodiment of the present invention, the diol is a C2-C8 diol, 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, 1,6-hexanediol, and 2-methyl-2,4-pentanediol; preferably, the mass ratio of the piperazine structure-containing raw material to the diol is 0.05 to 0.5:1, preferably 0.1 to 0.3:1; preferably, the mass ratio of the dibasic acid to the diol is 0.78 to 0.98:1, preferably 0.85 to 0.95:1.

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

[0018] Another object of the present invention is to provide a use of polyester polyol.

[0019] A use of a polyester polyol, wherein the polyester polyol is the polyester polyol mentioned above, or is a polyester polyol prepared by the above method, and the polyester polyol is used to prepare a thermoplastic polyurethane with heat resistance and high mechanical properties.

[0020] Another object of the present invention is to provide a thermoplastic polyurethane.

[0021] A thermoplastic polyurethane is prepared by using the polyester polyol or the polyester polyol prepared by the method.

[0022] Another object of the present invention is to provide a use of thermoplastic polyurethane.

[0023] A use of thermoplastic polyurethane, wherein the thermoplastic polyurethane is prepared by using the polyester polyol or the polyester polyol prepared by the method, and the thermoplastic polyurethane is used for preparing wires and cables, hoses and films.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] (1) Improved the heat resistance of thermoplastic polyurethane.

[0026] (2) Effectively improved the mechanical properties of polyurethane.

[0027] (3) Polyester polyols contain tertiary amine structures. No catalyst is required for polyol synthesis and polyurethane preparation. The products have no risk of organic metal residue precipitation and are safe and environmentally friendly. DETAILED DESCRIPTION

[0028] The present invention is further described below by means of specific examples. The examples described in the present invention are only used to illustrate the present invention and do not limit the scope of the present invention.

[0029] The chemical reagents used in the method of the present invention are all conventional reagents in the art and have a purity of chemically pure or above.

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

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

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

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

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

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

[0036] Nuclear magnetic resonance spectroscopy ( 13 C NMR) analysis: ANAVCE 500 nuclear magnetic resonance analyzer produced by Bruker, Germany was used, and CDCl3 was used as solvent.

[0037] The tensile test is based on ASTM D412, the tear strength is based on ASTM D624, and the tensile speed is 500 mm / min; the Vicat softening point test is based on ASTM D1525.

[0038] Example 1

[0039] Under nitrogen protection, 22 g of 1,4-bis(2-hydroxyethyl)piperazine, 187 g of adipic acid, and 220 g of ethylene glycol were added to a polyester reactor. The reactor was gradually heated to 160°C. After esterification reaction at normal pressure for 18 h, the reaction pressure was reduced to 1 kPa(A), the temperature was raised to 230°C, vacuum reaction was carried out for 6 h, the temperature was lowered and the material was discharged to obtain the target polyester polyol product.

[0040] The qualitative characterization results of the product are: 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, 45 g of 3-[4-(2-hydroxy-ethyl)-piperazine-1-yl]-1-propanol, 200 g of succinic acid, 62.5 g of glutaric acid, and 300 g of 1,4-butanediol were added to a polyester reactor. The reactor was gradually heated to 170°C. After esterification reaction at normal pressure for 16 hours, the reaction pressure was reduced to 2.5 kPa (A), the temperature was raised to 235°C, vacuum reaction was carried out for 8 hours, and the temperature was lowered to discharge the material to obtain the target polyester polyol product.

[0043] Example 3

[0044] Under nitrogen protection, 34 g of 1,4-piperazine diethylamine, 153 g of glutaric acid, and 170 g of 1,5-pentanediol were added to a polyester reactor. The reactor was gradually heated to 180°C. After esterification reaction at normal pressure for 14 hours, the reaction pressure was reduced to 3 kPa (A), the temperature was raised to 235°C, vacuum reaction was carried out for 10 hours, and the temperature was lowered to discharge the material to obtain the target polyester polyol product.

[0045] Example 4

[0046] Under nitrogen protection, 137.5 g of 2-(4-(2-aminoethyl)piperazine-1-yl)ethanol, 508.7 g of sebacic acid, and 550 g of 2-methyl-1,3-propanediol were added to a polyester reactor. The reactor was gradually heated to 190°C. After esterification at normal pressure for 16 hours, the reaction pressure was reduced to 5 kPa (A), the temperature was raised to 240°C, vacuum reaction was carried out for 16 hours, and the temperature was lowered to discharge the material to obtain the target polyester polyol product.

[0047] Example 5

[0048] Under nitrogen protection, 72 g of 1,4-bis(3-aminopropyl)piperazine, 228 g of azelaic acid, and 240 g of 1,4-butanediol were added to a polyester reactor. The reactor was gradually heated to 210°C. After esterification reaction at normal pressure for 16 hours, the reaction pressure was reduced to 5 kPa (A), the temperature was raised to 240°C, vacuum reaction was carried out for 11 hours, the temperature was lowered and the material was discharged to obtain the target polyester polyol product.

[0049] Comparative Example 1

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

[0051] Under nitrogen protection, 187 g of adipic acid and 220 g of ethylene glycol were fed into a polyester reactor. The reactor was gradually heated to 160°C. After esterification reaction at normal pressure for 18 hours, the reaction pressure was reduced to 1 kPa (A), the temperature was raised to 230°C, vacuum reaction was carried out for 6 hours, the temperature was lowered and the material was 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 ratios: polyester polyol: 55 parts, BDO: 10 parts, MDI isocyanate: 35 parts, stirred and heated to 100°C, poured into a mold, aged at 100°C for 10 hours, crushed and injection molded into test pieces at 220°C, and the test pieces were placed in an oven at 95°C 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 following table.

[0054] Table 1 Polyurethane performance test results

[0055]

[0056]

[0057] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as 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: Wherein, R1, R2, and R independently represent C2-C 10 One or more of the alkyl groups, preferably -C3H6-, straight or branched -C4H8-, straight or branched -C6H 12 - one or more, R3, R4 represent C2-C 10 One or more of alkylene oxides and alkylene amines, preferably one or more of -C2H4O, -C3H6O-, -C2H4NH-, -C3H6NH-; X is an integer of 5 to 20, preferably an integer of 8 to 16; Y is an integer of 1 to 5, preferably an integer of 2 to 4.

2. A method for preparing the polyester polyol according to claim 1, characterized in that: The method comprises the following steps: The piperazine structure-containing raw material is subjected to esterification polycondensation reaction with dibasic acid and diol to prepare a polyester polyol containing a piperazine structure.

3. The method according to claim 2, characterized in that The end groups of the piperazine structure-containing raw materials are one or more of hydroxyl, amino, and carboxyl groups, preferably one or more of 1,4-bis(2-hydroxyethyl)piperazine, 1,4-piperazine diethylamine, 2-(4-(2-aminoethyl)piperazine-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)-piperazine-1-yl]-1-propanol, 3-[4-(2-hydroxyethyl)piperazine-1-yl]-propionic acid, and [4-(2-hydroxy-ethyl)-piperazine-1-yl]-acetic acid; and / or 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; and / or the diol is a C2-C8 diol, 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, 1,6-hexanediol, and 2-methyl-2,4-pentanediol; Preferably, the mass ratio of the piperazine structure-containing raw material to the diol is 0.05 to 0.5:1, preferably 0.1 to 0.3:1; Preferably, the mass ratio of the dibasic acid to the diol is 0.78 to 0.98:1, preferably 0.85 to 0.95:

1.

4. The preparation method according to claim 2, characterized in that: The esterification polycondensation reaction comprises a normal pressure stage and a vacuum stage; Preferably, in the normal pressure stage of the esterification polycondensation reaction, the reaction temperature is 150-220°C, preferably 160-210°C, and the reaction time is 4-24h, preferably 8-18h; Preferably, in the vacuum stage of the esterification polycondensation reaction, the reaction temperature is 220-250° C., preferably 230-240° C., the reaction pressure is 0.1-8 kPa absolute pressure, preferably 1-5 kPa absolute pressure, and the reaction time is 4-20 h, preferably 6-16 h.

5. Use of a polyester polyol, wherein the polyester polyol is the polyester polyol according to claim 1, or is a polyester polyol prepared by the method according to any one of claims 2 to 4, and the polyester polyol is used to prepare a thermoplastic polyurethane with heat resistance and high mechanical properties.

6. A thermoplastic polyurethane, which is prepared by using the polyester polyol according to claim 1 or the polyester polyol prepared by the method according to any one of claims 2 to 4.

7. Use of a thermoplastic polyurethane, wherein the thermoplastic polyurethane is prepared by the polyester polyol according to claim 1, or the polyester polyol prepared by the method according to any one of claims 2 to 4, and the thermoplastic polyurethane is used to prepare wires and cables, hoses, and films.

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