Polyurethane elastomer for high-temperature-resistant rubber roller and preparation method of polyurethane elastomer

Abstract

The invention belongs to the technical field of polyurethane elastomers, and particularly relates to a polyurethane elastomer for a high-temperature-resistant rubber roller and a preparation method of the polyurethane elastomer. The polyurethane elastomer is prepared by mixing a prepolymer and a chain extender, curing and vulcanizing; the prepolymer is prepared by carrying out a polymerization reaction on block copolymerization type polycarbonate diol and isocyanate; the preparation method of the block copolymerized polycarbonate diol comprises the following steps: firstly, carrying out transesterification on dimethyl carbonate and polypropylene carbonate glycol under the action of an organic tin catalyst to obtain an intermediate; and then, carrying out condensation polymerization on the intermediate and 1, 4-butanediol to obtain the product. By adopting the block copolymer diol, the high temperature resistance of polycarbonate is effectively utilized, the temperature resistance of the product is improved, and the service life of the product under a high temperature condition is prolonged; meanwhile, a soft segment is introduced through a block, so that the flexibility of the product is effectively improved, and better use performance is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane elastomers, and particularly relates to a polyurethane elastomer for a high-temperature resistant rubber roller and a preparation method thereof. Background Art

[0002] Polyurethane rubber rollers are roll-shaped products made of metal or other materials as the core and polyurethane material as the outer layer, which are vulcanized and widely used in various types of printing machinery, papermaking machinery, textile machinery, printing and dyeing machinery and other conveying and processing equipment. In the metallurgical industry, polyurethane rubber rollers are not only suitable for the conduction, transportation and traction of materials such as stainless steel, steel, and non-ferrous metals on various production lines, but also suitable for acid and alkali cleaning of metals, tension curling, and metallurgical plate squeezing. Therefore, polyurethane rubber rollers need to have good high temperature resistance and corrosion resistance.

[0003] However, the service life of existing polyurethane rubber roller products is significantly reduced under high temperature conditions, so their heat resistance needs to be improved. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a polyurethane elastomer for high-temperature resistant rubber rollers. By adopting block copolymer diols, not only the high-temperature resistance of polycarbonate is effectively utilized to improve the temperature resistance of the product and extend the service life of the product under high temperature conditions; at the same time, a soft segment is introduced through the block, so that the flexibility of the product is effectively improved, thereby having better performance.

[0005] Another object of the present invention is to provide a method for preparing a polyurethane elastomer for a high temperature resistant rubber roller, which is scientific, reasonable, simple and easy to implement.

[0006] The technical solution adopted by the present invention is as follows: The polyurethane elastomer for high temperature resistant rubber roller is prepared by mixing a prepolymer and a chain extender in a mass ratio of 100:(6-65), and then curing and vulcanizing. The prepolymer is prepared by polymerization reaction of block copolymerized polycarbonate diol and isocyanate in a mass ratio of 100:(14-46); The preparation method of the block copolymer polycarbonate diol is as follows: first, dimethyl carbonate and polypropylene carbonate diol are subjected to an ester exchange reaction under the action of an organic tin catalyst to obtain an intermediate; then, the intermediate is subjected to a condensation reaction with 1,4-butanediol to obtain the block copolymer polycarbonate diol.

[0007] The chain extender is one of hydroquinone dihydroxyethyl ether (HQEE), 4,4'-methylene-bis(3-chloro-2,6-diethylaniline) (MCDEA) or a copolymer of 3,3'-dichloro-4,4'-diaminodiphenylmethane and N,N'-4,4'-diphenylmethane bismaleimide (BMI).

[0008] The preparation method of the copolymer of 3,3'-dichloro-4,4'-diaminodiphenylmethane and N,N'-4,4'-diphenylmethane bismaleimide is as follows: Mix 3,3'-dichloro-4,4'-diaminodiphenylmethane and N,N'-4,4'-diphenylmethane bismaleimide in a molar ratio of 1:(1-3), keep warm for reaction at 120-140°C for 0.5-1h, cool to room temperature, and crush to obtain a copolymer of 3,3'-dichloro-4,4'-diaminodiphenylmethane and N,N'-4,4'-diphenylmethane bismaleimide (BMI-MOCA). The molar ratio of 3,3'-dichloro-4,4'-diaminodiphenylmethane to N,N'-4,4'-diphenylmethane bismaleimide is preferably 1:2.

[0009] The -NCO content of the prepolymer is 3-6wt.%.

[0010] The isocyanate is one or more of isophorone diisocyanate (IPDI), toluene-2,4-diisocyanate (TDI) or p-phenylene diisocyanate (PPDI).

[0011] The number average molecular weight of the block copolymer polycarbonate diol is 1000-2000 g / mol.

[0012] The preparation method of the block copolymerized polycarbonate diol is as follows: Add dimethyl carbonate and polypropylene carbonate diol into a reaction kettle, then add an organic tin catalyst, heat up to 140-145°C to start water discharge, control the condensation reflux temperature to 105-110°C, carry out ester exchange reaction, react for 2-5 hours, then heat up to 220-240°C, continue to react for 2-5 hours to obtain an intermediate; add 1,4-butanediol to the intermediate for polycondensation reaction, react for 2-5 hours to obtain a block copolymer polycarbonate diol.

[0013] The number average molecular weight of the polypropylene carbonate diol is 500-1000 g / mol.

[0014] The molar ratio of dimethyl carbonate to polypropylene carbonate diol is 1:(1-1.05); the molar ratio of the intermediate to 1,4-butanediol is 1:(1-5).

[0015] The method for preparing the polyurethane elastomer for the high temperature resistant rubber roller comprises the following steps: (1) reacting a block copolymer polycarbonate diol with an isocyanate at 75-85°C for 3-5 hours to obtain a prepolymer; (2) The prepolymer is mixed with the chain extender, poured into a mold at 100-110°C, cured, opened after 30-60 minutes, and vulcanized for 10-16 hours to obtain a polyurethane elastomer for high temperature resistant rubber rollers.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention adopts block copolymer diol, which not only effectively utilizes the high temperature resistance of polycarbonate to improve the heat resistance of the product and prolong the service life of the product under high temperature conditions, but also introduces a soft segment through the block, so that the flexibility of the product is effectively improved, thereby having better performance. In addition, by curing with a chain extender with good heat resistance effect, the heat resistance effect of the product is further improved. DETAILED DESCRIPTION

[0017] The present invention is further described below with reference to the embodiments, but they do not limit the implementation of the present invention.

[0018] Unless otherwise specified, the raw materials used in the examples and comparative examples are conventional commercially available raw materials, and the process methods used in the examples and comparative examples are conventional methods in the art unless otherwise specified.

[0019] Some of the raw materials used in the examples and comparative examples are described as follows: Polypropylene carbonate diol has a number average molecular weight of 500 g / mol. The preparation method is as follows: add 30 g of bimetallic catalyst DMC and 2500 g of propylene oxide to a dry 5000 mL high-pressure reactor, add 1300 g of CO2 under stirring conditions, raise the temperature to 60°C while stirring, and react for 24 hours to obtain the product.

[0020] Polypropylene carbonate diol PPCD 211 was purchased from Huizhou Daya Bay Dazhi Fine Chemical Co., Ltd., with a number average molecular weight of 1000 g / mol.

[0021] Polyester diol PE-2020 was purchased from Shandong Yinuowei Polyurethane Co., Ltd., with a number average molecular weight of 2000 g / mol.

[0022] Polyester diol PE-2010 was purchased from Shandong Yinuowei Polyurethane Co., Ltd., with a number average molecular weight of 1000 g / mol.

[0023] Example 1 The method for preparing the polyurethane elastomer for the high temperature resistant rubber roller comprises the following steps: (1) 87 parts of a block copolymer polycarbonate diol having a number average molecular weight of 2000 g / mol and 13 parts of p-phenylene diisocyanate were reacted at 85° C. for 5 hours to obtain a prepolymer having an -NCO content of 3 wt.%; (2) The prepolymer and hydroquinone dihydroxyethyl ether in a mass ratio of 100:6.5 were mixed, poured into a mold at 100°C, cured, opened the mold after 60 minutes, and vulcanized for 10 hours to obtain a polyurethane elastomer for high temperature resistant rubber rollers.

[0024] The preparation method of the block copolymerized polycarbonate diol is as follows: Dimethyl carbonate and polypropylene carbonate diol PPCD 211 with a molar ratio of 1:1 were added to a reactor, and then dibutyltin dilaurate was added (the amount added was 0.05wt.% of the total amount of dimethyl carbonate and polypropylene carbonate diol), stirring was started, the temperature was raised to 142.5±2.5°C, water began to come out, the condensation reflux temperature was controlled to be 107.5±2.5°C, an ester exchange reaction was carried out, and after reacting for 2 hours, the temperature was gradually raised to 230±10°C, and the reaction was continued for 5 hours to obtain an intermediate; 1,4-butanediol was added to the intermediate for a condensation reaction, and after reacting for 2 hours, a block copolymer polycarbonate diol was obtained, wherein the molar ratio of the intermediate to 1,4-butanediol was 1:5.

[0025] Example 2 The method for preparing the polyurethane elastomer for the high temperature resistant rubber roller comprises the following steps: (1) 77.5 parts of a block copolymer polycarbonate diol having a number average molecular weight of 1500 g / mol and 22.5 parts of isophorone diisocyanate were reacted at 80° C. for 4.5 hours to obtain a prepolymer having an -NCO content of 4 wt.%; (2) The prepolymer was mixed with 4,4'-methylene-bis(3-chloro-2,6-diethylaniline) in a mass ratio of 100:16.3, poured into a mold at 110°C, cured, opened the mold after 40 minutes, and vulcanized for 16 hours to obtain a polyurethane elastomer for high temperature resistant rubber rollers.

[0026] The preparation method of the block copolymerized polycarbonate diol is as follows: Dimethyl carbonate and polypropylene carbonate diol PPCD 211 with a molar ratio of 1:1.02 are added to a reactor, and then dibutyltin dilaurate is added in an amount of 0.05wt.% of the total amount of dimethyl carbonate and polypropylene carbonate diol, and stirring is started. The temperature is raised to 142.5±2.5°C to start water discharge, and the condensation reflux temperature is controlled to be 107.5±2.5°C to carry out ester exchange reaction. After reacting for 5 hours, the temperature is gradually raised to 230±10°C and the reaction is continued for 2 hours to obtain an intermediate; 1,4-butanediol is added to the intermediate for polycondensation reaction. After reacting for 5 hours, a block copolymer polycarbonate diol is obtained, wherein the molar ratio of the intermediate to 1,4-butanediol is 1:3.

[0027] Example 3 The method for preparing the polyurethane elastomer for the high temperature resistant rubber roller comprises the following steps: (1) 76 parts of a block copolymer polycarbonate diol having a number average molecular weight of 1000 g / mol and 24 parts of toluene-2,4-diisocyanate were reacted at 80° C. for 3.5 hours to obtain a prepolymer having an -NCO content of 5 wt.%; (2) The prepolymer was mixed with a copolymer of 3,3'-dichloro-4,4'-diaminodiphenylmethane and N,N'-4,4'-diphenylmethane bismaleimide in a mass ratio of 100:53, poured into a mold at 105°C, cured, opened the mold after 50 minutes, and vulcanized for 13 hours to obtain a polyurethane elastomer for high temperature resistant rubber rollers.

[0028] The preparation method of the copolymer of 3,3'-dichloro-4,4'-diaminodiphenylmethane and N,N'-4,4'-diphenylmethane bismaleimide is as follows: 3,3'-dichloro-4,4'-diaminodiphenylmethane and N,N'-4,4'-diphenylmethane bismaleimide are mixed in a molar ratio of 1:2, and the mixture is heated at 130±10°C for 1 hour, cooled to room temperature, and crushed to obtain the copolymer.

[0029] The preparation method of the block copolymerized polycarbonate diol is as follows: Dimethyl carbonate and polypropylene carbonate diol with a molar ratio of 1:1.05 were added to a reaction kettle, and then dibutyltin dilaurate was added (the amount added was 0.05wt.% of the total amount of dimethyl carbonate and polypropylene carbonate diol), stirring was started, the temperature was raised to 142.5±2.5°C, water began to come out, the condensation reflux temperature was controlled to be 107.5±2.5°C, an ester exchange reaction was carried out, and after reacting for 3 hours, the temperature was gradually raised to 230±10°C, and the reaction was continued for 4 hours to obtain an intermediate; 1,4-butanediol was added to the intermediate for a condensation reaction, and after reacting for 3 hours, a block copolymer polycarbonate diol was obtained, wherein the molar ratio of the intermediate to 1,4-butanediol was 1:1.

[0030] Example 4 The method for preparing the polyurethane elastomer for the high temperature resistant rubber roller comprises the following steps: (1) 75 parts of a block copolymer polycarbonate diol having a number average molecular weight of 1200 g / mol, 12.5 parts of p-phenylene diisocyanate and 12.5 parts of isophorone diisocyanate were reacted at 75° C. for 3 hours to obtain a prepolymer having an -NCO content of 6 wt.%; (2) The prepolymer was mixed with a copolymer of 3,3'-dichloro-4,4'-diaminodiphenylmethane and N,N'-4,4'-diphenylmethane bismaleimide in a mass ratio of 100:65, poured into a mold at 105°C, cured, opened the mold after 50 minutes, and vulcanized for 13 hours to obtain a polyurethane elastomer for high temperature resistant rubber rollers.

[0031] The preparation method of the copolymer of 3,3'-dichloro-4,4'-diaminodiphenylmethane and N,N'-4,4'-diphenylmethane bismaleimide is as follows: 3,3'-dichloro-4,4'-diaminodiphenylmethane and N,N'-4,4'-diphenylmethane bismaleimide are mixed in a molar ratio of 1:2, and the mixture is heated at 130±10°C for 1 hour, cooled to room temperature, and crushed to obtain the copolymer.

[0032] The preparation method of the block copolymerized polycarbonate diol is as follows: Dimethyl carbonate and polypropylene carbonate diol with a molar ratio of 1:1.05 were added to a reaction kettle, and then dibutyltin dilaurate was added (the amount added was 0.05wt.% of the total amount of dimethyl carbonate and polypropylene carbonate diol), stirring was started, the temperature was raised to 142.5±2.5°C, water began to come out, the condensation reflux temperature was controlled to be 107.5±2.5°C, an ester exchange reaction was carried out, and after reacting for 4 hours, the temperature was gradually raised to 230±10°C, and the reaction was continued for 3 hours to obtain an intermediate; 1,4-butanediol was added to the intermediate for a condensation reaction, and after reacting for 4 hours, a block copolymer polycarbonate diol was obtained, wherein the molar ratio of the intermediate to 1,4-butanediol was 1:2.

[0033] Example 5 The method for preparing the polyurethane elastomer for the high temperature resistant rubber roller comprises the following steps: (1) 68.5 parts of a block copolymer polycarbonate diol having a number average molecular weight of 1000 g / mol and 31.5 parts of isophorone diisocyanate were reacted at 80° C. for 3 h to obtain a prepolymer having an -NCO content of 6 wt.%; (2) The prepolymer and hydroquinone dihydroxyethyl ether in a mass ratio of 100:13 were mixed, poured into a mold at 110°C, cured, opened the mold after 50 minutes, and vulcanized for 16 hours to obtain a polyurethane elastomer for high temperature resistant rubber rollers.

[0034] The preparation method of the block copolymerized polycarbonate diol is as follows: Dimethyl carbonate and polypropylene carbonate diol with a molar ratio of 1:1.05 were added to a reaction kettle, and then dibutyltin dilaurate was added (the amount added was 0.05wt.% of the total amount of dimethyl carbonate and polypropylene carbonate diol), stirring was started, the temperature was raised to 142.5±2.5°C, water began to come out, the condensation reflux temperature was controlled to be 107.5±2.5°C, an ester exchange reaction was carried out, and after reacting for 4 hours, the temperature was gradually raised to 230±10°C, and the reaction was continued for 3 hours to obtain an intermediate; 1,4-butanediol was added to the intermediate for a condensation reaction, and after reacting for 4 hours, a block copolymer polycarbonate diol was obtained, wherein the molar ratio of the intermediate to 1,4-butanediol was 1:2.

[0035] Comparative Example 1 The preparation method of the polyurethane elastomer comprises the following steps: (1) 87 parts of PE-2020 with a number average molecular weight of 2000 g / mol and 13 parts of p-phenylene diisocyanate were reacted at 85° C. for 5 h to obtain a prepolymer with an -NCO content of 3 wt.%; (2) The prepolymer and hydroquinone dihydroxyethyl ether in a mass ratio of 100:6.5 were mixed, poured into a mold at 100°C, cured, opened the mold after 60 minutes, and vulcanized for 10 hours to obtain a polyurethane elastomer.

[0036] Comparative Example 2 The preparation method of the polyurethane elastomer comprises the following steps: (1) A mixture of 48.7 parts of PE-2020 and 26.3 parts of PE-2010 (the number average molecular weight of the mixture is 1200 g / mol), 12.5 parts of p-phenylene diisocyanate and 12.5 parts of isophorone diisocyanate were reacted at 75° C. for 3 h to obtain a prepolymer with an -NCO content of 6 wt.%; (2) The prepolymer was mixed with a copolymer of 3,3'-dichloro-4,4'-diaminodiphenylmethane and N,N'-4,4'-diphenylmethane bismaleimide in a mass ratio of 100:65, poured into a mold at 105°C, cured, opened the mold after 50 minutes, and vulcanized for 13 hours to obtain a polyurethane elastomer.

[0037] The preparation method of the copolymer of 3,3'-dichloro-4,4'-diaminodiphenylmethane and N,N'-4,4'-diphenylmethane bismaleimide is as follows: 3,3'-dichloro-4,4'-diaminodiphenylmethane and N,N'-4,4'-diphenylmethane bismaleimide are mixed in a molar ratio of 1:2, and the mixture is heated at 130±10°C for 1 hour, cooled to room temperature, and crushed to obtain the copolymer.

[0038] Comparative Example 3 The preparation method of the polyurethane elastomer comprises the following steps: (1) 75 parts of a block copolymer polycarbonate diol having a number average molecular weight of 1200 g / mol, 12.5 parts of p-phenylene diisocyanate and 12.5 parts of isophorone diisocyanate were reacted at 75° C. for 3 hours to obtain a prepolymer having an -NCO content of 6 wt.%; (2) The prepolymer was mixed with 3,3'-dichloro-4,4'-diaminodiphenylmethane in a mass ratio of 100:14.5, poured into a mold at 105°C, cured, opened the mold after 50 minutes, and vulcanized for 13 hours to obtain a polyurethane elastomer.

[0039] The polyurethane elastomers prepared in Examples 1-5 and Comparative Examples 1-3 were tested for performance, and the testing method was as follows: Hardness (A): Refer to GB / T 531.1-2008; Hardness at 100℃ (A): Refer to GB / T 531.1-2008, place the sample at 100℃ for 60 minutes before testing; Tensile strength (MPa): refer to GB / T 528-2009; Tensile strength at 100℃ (MPa): Refer to GB / T 528-2009. The sample is placed at 100℃ for 60 minutes before testing.

[0040] The test results are shown in Table 1: Table 1 Performance test results

[0041] It can be seen from the data in Table 1 that the hardness and tensile strength of the polyurethane elastomers prepared in Examples 1-5 after being placed at 100°C for 60 minutes change less than those tested at room temperature, and the tensile strength retention rate at 100°C is higher. This is because heat-resistant segments are added to the products, and chain extenders with heat-resistant effects are used for curing, which makes them have better heat resistance.

[0042] Since no block copolymer polycarbonate diol is used in Comparative Example 1-2, its heat resistance and performance retention rate are significantly reduced. This is because the product segment lacks a heat-resistant structure, and thus the heat resistance effect of the obtained polyurethane elastomer is significantly reduced.

[0043] In Comparative Example 3, since a chain extender with good heat resistance effect was not used for curing, the heat resistance effect of the obtained polyurethane elastomer was also reduced.

Claims

1. A polyurethane elastomer for a high temperature resistant rubber roller, characterized in that: It is prepared by mixing a prepolymer and a chain extender in a mass ratio of 100:(6-65), and then curing and vulcanizing. The prepolymer is prepared by polymerization reaction of block copolymerized polycarbonate diol and isocyanate in a mass ratio of 100:(14-46); The preparation method of the block copolymer polycarbonate diol is as follows: first, dimethyl carbonate and polypropylene carbonate diol are subjected to an ester exchange reaction under the action of an organic tin catalyst to obtain an intermediate; then, the intermediate is subjected to a condensation reaction with 1,4-butanediol to obtain the block copolymer polycarbonate diol.

2. The polyurethane elastomer for high temperature resistant rubber roller according to claim 1, characterized in that: The chain extender is one of hydroquinone dihydroxyethyl ether, 4,4'-methylene-bis(3-chloro-2,6-diethylaniline) or a copolymer of 3,3'-dichloro-4,4'-diaminodiphenylmethane and N,N'-4,4'-diphenylmethane bismaleimide.

3. The polyurethane elastomer for high temperature resistant rubber roller according to claim 2, characterized in that: The preparation method of the copolymer of 3,3'-dichloro-4,4'-diaminodiphenylmethane and N,N'-4,4'-diphenylmethane bismaleimide is as follows: Mix 3,3'-dichloro-4,4'-diaminodiphenylmethane and N,N'-4,4'-diphenylmethane bismaleimide in a molar ratio of 1:(1-3), and keep the mixture for reaction at 120-140°C for 0.5-1h to obtain a copolymer of 3,3'-dichloro-4,4'-diaminodiphenylmethane and N,N'-4,4'-diphenylmethane bismaleimide.

4. The polyurethane elastomer for high temperature resistant rubber roller according to claim 1, characterized in that: The -NCO content of the prepolymer is 3-6wt.%.

5. The polyurethane elastomer for high temperature resistant rubber roller according to claim 1, characterized in that: The isocyanate is one or more of isophorone diisocyanate, toluene-2,4-diisocyanate or p-phenylene diisocyanate.

6. The polyurethane elastomer for high temperature resistant rubber roller according to claim 1, characterized in that: The number average molecular weight of the block copolymer polycarbonate diol is 1000-2000 g / mol.

7. The polyurethane elastomer for high temperature resistant rubber roller according to claim 1, characterized in that: The preparation method of the block copolymerized polycarbonate diol is as follows: Add dimethyl carbonate and polypropylene carbonate diol into a reaction kettle, then add an organic tin catalyst, heat up to 140-145°C to start water discharge, control the condensation reflux temperature to 105-110°C, carry out ester exchange reaction, react for 2-5 hours, then heat up to 220-240°C, continue to react for 2-5 hours to obtain an intermediate; add 1,4-butanediol to the intermediate for polycondensation reaction, react for 2-5 hours to obtain a block copolymer polycarbonate diol.

8. The polyurethane elastomer for high temperature resistant rubber roller according to claim 7, characterized in that: The number average molecular weight of the polypropylene carbonate diol is 500-1000 g / mol.

9. The polyurethane elastomer for high temperature resistant rubber roller according to claim 7, characterized in that: The molar ratio of dimethyl carbonate to polypropylene carbonate diol is 1:(1-1.05); the molar ratio of the intermediate to 1,4-butanediol is 1:(1-5).

10. A method for preparing the polyurethane elastomer for high temperature resistant rubber roller according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) reacting a block copolymer polycarbonate diol with an isocyanate at 75-85°C for 3-5 hours to obtain a prepolymer; (2) The prepolymer is mixed with the chain extender, poured into a mold at 100-110°C, cured, opened after 30-60 minutes, and vulcanized for 10-16 hours to obtain a polyurethane elastomer for high temperature resistant rubber rollers.

Images