A high temperature resistant polyurethane sealing ring and preparation method thereof

Abstract

The present invention relates to the technical field of sealing ring production, specifically to a high temperature resistant polyurethane sealing ring and a preparation method thereof; the high temperature resistant polyurethane sealing ring is composed of the following raw materials by weight: 30 to 40 parts of polyurethane elastomer, 3 to 6 parts of functional additives, 3 to 5 parts of vulcanizing agent, 2 to 4 parts of nano carbon fiber, 4 to 7 parts of compound nano powder and 2 to 5 parts of antioxidant; the polyurethane elastomer, functional additives, vulcanizing agent, nano carbon fiber, compound nano powder and antioxidant are put into a mixing device for mixing and stirring, and then transferred to a mixer for refining, the refining mixture is transferred to a vulcanizing device for vulcanization treatment, and then formed by a hot pressing molding machine, and the final product is a high temperature resistant polyurethane sealing ring. The high temperature resistant polyurethane sealing ring prepared by the present invention not only has good mechanical properties, but also has excellent heat resistance and flame retardancy, effectively ensuring its quality and quality.

Description

Technical Field

[0001] The invention relates to the technical field of sealing ring production, in particular to a high-temperature resistant polyurethane sealing ring and a preparation method thereof. Background Art

[0002] Sealing rings are widely used in automobiles, wires and cables, chemicals and other fields. With the development of science and technology, the requirements for the heat resistance of rubber sealing rings are becoming higher and higher.

[0003] Polyurethane, whose full name is polyurethane, is a polymer material formed by the condensation reaction of polyols and polyisocyanates and has excellent mechanical properties and extremely strong plasticity.

[0004] In the patent document with application number "CN201811264870.4" and titled "A high temperature resistant modified polyurethane rubber sealing ring and its preparation method", it is recorded that "the raw materials are as follows: organosilicon modified polyurethane resin rubber, nano-silicon dioxide, polypropylene, nano-carbon fiber, zinc oxide, plasticizer, anti-aging agent, vulcanizer, and the steps are as follows: 1) Mix and stir organosilicon modified polyurethane resin rubber, nano-silicon dioxide, polypropylene, nano-carbon fiber, plasticizer, zinc oxide, anti-aging agent, and vulcanizer to obtain a mixture; 2) Heat the mixture to obtain a rubber mix; 3) Place the rubber mix on a sealing ring mold, pressurize and plasticize it to obtain a molded part; 4) Vulcanize the molded part to obtain the obtained part. The high temperature resistant modified polyurethane rubber sealing ring prepared by the present invention has the characteristics of high temperature resistance, high compressive strength, high elasticity, and high wear resistance coefficient. Compared with ordinary sealing rings, its performance is greatly improved. At the same time, the preparation process is simple, environmentally friendly, and convenient for industrial production, and it has broad application prospects."

[0005] Although the polyurethane sealing ring manufactured by the above patent document has the advantages of excellent heat resistance, its flame retardant performance is relatively insufficient and still needs further improvement. Based on this, the present invention provides a high temperature resistant polyurethane sealing ring and a preparation method thereof to solve the above technical problems! Summary of the invention

[0006] The purpose of the present invention is to provide a high temperature resistant polyurethane sealing ring and a preparation method thereof. The prepared high temperature resistant polyurethane sealing ring not only has good mechanical properties, but also has excellent heat resistance and flame retardancy, effectively ensuring its quality.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] The invention provides a high temperature resistant polyurethane sealing ring, which is composed of the following raw materials in parts by weight: 30 to 40 parts of polyurethane elastomer, 3 to 6 parts of functional additives, 3 to 5 parts of vulcanizing agent, 2 to 4 parts of nano carbon fibers, 4 to 7 parts of compound nano powder and 2 to 5 parts of antioxidant.

[0009] Furthermore, the preparation process of the polyurethane elastomer is as follows:

[0010] A proper amount of hydroxy-terminated polybutadiene and toluene-2,4-diisocyanate are fully mixed in a mass ratio of 1:0.2-0.5, and treated at 82-86° C. for 20-30 minutes to obtain a first prepolymer;

[0011] A suitable amount of polyhydroxy polybutadiene and toluene-2,4-diisocyanate are fully mixed in a mass ratio of 1:0.2-0.5, and treated at 82-86° C. for 20-30 minutes to obtain a second prepolymer;

[0012] A proper amount of polyoxypropylene glycol and toluene-2,4-diisocyanate are fully mixed in a mass ratio of 1:0.2-0.5, and treated at 82-86° C. for 20-30 minutes to obtain a third prepolymer;

[0013] The first prepolymer, the second prepolymer and the third prepolymer are fully mixed to obtain a mixed prepolymer, and then 1,4-cyclohexanedimethanol and dibutyltin dilaurate are added to continue mixing. After injection molding, the prepolymer is placed in an oven at 100° C. for aging for 190 to 200 minutes to obtain a polyurethane elastomer.

[0014] Furthermore, the mass ratio of the first prepolymer, the second prepolymer and the third prepolymer added in the mixed prepolymer is 1:0.3-0.5:0.5-0.7.

[0015] Furthermore, the addition amounts of 1,4-cyclohexanedimethanol and dibutyltin dilaurate are 0.012-0.036% and 0.022-0.046% of the mass of the mixed prepolymer, respectively.

[0016] Furthermore, the preparation process of the functional additive is as follows:

[0017] The base material is placed in an appropriate amount of γ-aminopropyltriethoxysilane at a solid-liquid ratio of 0.02-0.12 g / mL and fully mixed, and then 0.2-0.4% of diatomaceous earth by weight of the base material is added thereto, and the mixture is treated at 80-90°C and 100-120 r / min for 20-25 minutes;

[0018] After filtration, the product is washed with anhydrous ethanol and deionized water for 2 to 4 times respectively, and dried at 70 to 80° C. to a constant weight to obtain a functional additive.

[0019] Furthermore, the preparation process of the base material is as follows:

[0020] Place water glass in an appropriate amount of 60-70% hydrochloric acid solution at a mass ratio of 0.02-0.12:1, mix thoroughly, treat at 20-30°C for 20-30 minutes, add deionized water with a mass of 120-150% of the hydrochloric acid solution, treat at 80-120 r / min for 20-30 minutes, and obtain a modified solution;

[0021] The nano-muscovite powder is placed in a proper amount of modified liquid at a solid-liquid ratio of 0.22-0.32 g / mL, treated at 50-60° C. for 50-60 minutes, filtered, and dried at 70-80° C. to constant weight to obtain a base material.

[0022] Furthermore, the vulcanizing agent is selected from any one of di-2,5-hexane and tert-butyl perbenzoate.

[0023] Furthermore, the antioxidant is selected from any one of antioxidant 1010, antioxidant 1076, and antioxidant CA.

[0024] Furthermore, the compound nano powder is compounded by nano titanium dioxide and nano zinc oxide in a mass ratio of 1:0.6-0.8.

[0025] The second aspect of the present invention: also provides a method for preparing the above-mentioned high temperature resistant polyurethane sealing ring, comprising the following steps:

[0026] Step 1: accurately weigh the polyurethane elastomer, functional additives, vulcanizing agent, nano-carbon fiber, compounded nano-powder and antioxidant, and put the polyurethane elastomer, functional additives, vulcanizing agent, nano-carbon fiber, compounded nano-powder and antioxidant into a mixing device for mixing and stirring;

[0027] Step 2: After the mixture is evenly mixed, the mixture is transferred into a mixer and subjected to a refining process at a temperature of 150 to 160°C;

[0028] Step 3: The mixed mixture is then transferred to a vulcanization device for vulcanization treatment, and then formed by a hot pressing molding machine. The final product is a high-temperature resistant polyurethane sealing ring. The vulcanization treatment pressure is 5-8 MPa, the temperature is 150-160°C, and the vulcanization time is set to 30-50 min. The molding temperature of the hot pressing molding machine is 170-190°C.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] In the present invention, polyurethane elastomer, functional additive, vulcanizing agent, nano-carbon fiber, compounded nano-powder and antioxidant are used as raw materials. The polyurethane elastomer, functional additive, vulcanizing agent, nano-carbon fiber, compounded nano-powder and antioxidant are put into a mixing device for mixing and stirring, and then transferred to a mixer for refining. The refining mixture is transferred to a vulcanizing device for vulcanization treatment, and then formed by a hot pressing molding machine. The final product is a high-temperature resistant polyurethane sealing ring. The high-temperature resistant polyurethane sealing ring prepared by the present invention not only has good mechanical properties, but also has excellent heat resistance and flame retardancy, which effectively guarantees its quality. The high-temperature resistant polyurethane sealing ring and the preparation method thereof provided by the present invention have a broader market prospect and are more suitable for promotion. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0032] Example 1

[0033] The present embodiment provides a high temperature resistant polyurethane sealing ring, which is composed of the following raw materials in parts by weight: 30 parts of polyurethane elastomer, 3 parts of functional additives, 3 parts of vulcanizing agent, 2 parts of nano-carbon fibers, 4 parts of compound nano-powders and 2 parts of antioxidants.

[0034] Among them, the preparation process of polyurethane elastomer is as follows:

[0035] A proper amount of hydroxy-terminated polybutadiene and toluene-2,4-diisocyanate were fully mixed in a mass ratio of 1:0.2, and treated at 82° C. for 20 minutes to obtain a first prepolymer;

[0036] A proper amount of polyhydroxy polybutadiene and toluene-2,4-diisocyanate were fully mixed in a mass ratio of 1:0.2, and treated at 82° C. for 20 minutes to obtain a second prepolymer;

[0037] A proper amount of polyoxypropylene glycol and toluene-2,4-diisocyanate were fully mixed in a mass ratio of 1:0.2, and treated at 82° C. for 20 minutes to obtain a third prepolymer;

[0038] The first prepolymer, the second prepolymer and the third prepolymer were fully mixed to obtain a mixed prepolymer, and 1,4-cyclohexanedimethanol and dibutyltin dilaurate were added to continue mixing. After injection molding, the prepolymer was placed in an oven at 100° C. for aging for 190 minutes to obtain a polyurethane elastomer.

[0039] Furthermore, the mass ratio of the added amounts of the first prepolymer, the second prepolymer and the third prepolymer in the mixed prepolymer is 1:0.3:0.5.

[0040] The addition amounts of 1,4-cyclohexanedimethanol and dibutyltin dilaurate were 0.012% and 0.022% of the mass of the mixed prepolymer, respectively.

[0041] In addition, the preparation process of the functional additive is as follows:

[0042] The base material is placed in an appropriate amount of γ-aminopropyltriethoxysilane at a solid-liquid ratio of 0.02 g / mL and fully mixed, and then 0.2-0.4% of diatomaceous earth by weight of the base material is added thereto, and the mixture is treated at 80°C and 100 r / min for 20 minutes;

[0043] After filtration, the product was washed twice with anhydrous ethanol and deionized water respectively, and dried at 70° C. to constant weight to obtain a functional additive.

[0044] Further, the preparation process of the base material is as follows:

[0045] Place water glass in an appropriate amount of 60% hydrochloric acid solution at a mass ratio of 0.02:1, mix thoroughly, treat at 20°C for 20 minutes, add deionized water with a mass of 120% of the hydrochloric acid solution, treat at 80r / min for 20 minutes, and obtain a modified solution;

[0046] The nano-muscovite powder was placed in a proper amount of modified liquid at a solid-liquid ratio of 0.22 g / mL, treated at 50° C. for 50 min, filtered, and dried at 70° C. to constant weight to obtain a base material.

[0047] In this embodiment, it should be noted that water glass was purchased from Shandong Jinjuwang Chemical Co., Ltd., and nano-muscovite powder was purchased from Lingshou County Huajing Mica Co., Ltd.

[0048] Among them, the vulcanizing agent is di-2,5-hexane.

[0049] The antioxidant used is antioxidant 1010.

[0050] The compound nano powder is compounded by nano titanium dioxide and nano zinc oxide in a mass ratio of 1:0.6.

[0051] In addition, this embodiment also provides a method for preparing the above-mentioned high temperature resistant polyurethane sealing ring, comprising the following steps:

[0052] Step 1: accurately weigh the polyurethane elastomer, functional additives, vulcanizing agent, nano-carbon fiber, compounded nano-powder and antioxidant, and put the polyurethane elastomer, functional additives, vulcanizing agent, nano-carbon fiber, compounded nano-powder and antioxidant into a mixing device for mixing and stirring;

[0053] Step 2: After the mixture is evenly mixed, the mixture is transferred into a mixer and subjected to a refining process at a temperature of 150°C;

[0054] Step 3: The kneaded mixture is then transferred to a vulcanization device for vulcanization treatment, and then formed by a hot pressing molding machine. The final product is a high-temperature resistant polyurethane sealing ring; wherein the vulcanization treatment pressure is 5 MPa, the temperature is 150°C, and the vulcanization time is set to 30 minutes; the molding temperature of the hot pressing molding machine is 170°C.

[0055] Example 2

[0056] The preparation method of the high temperature resistant polyurethane sealing ring provided in this embodiment is basically the same as that in embodiment 1, except that: the specific raw material composition and the specific preparation method of the high temperature resistant polyurethane sealing ring in this embodiment are different; the specific raw material composition and the specific preparation method of the high temperature resistant polyurethane sealing ring in this embodiment are as follows:

[0057] A high-temperature resistant polyurethane sealing ring is composed of the following raw materials in parts by weight: 35 parts of polyurethane elastomer, 4 parts of functional additives, 4 parts of vulcanizing agents, 3 parts of nano-carbon fibers, 5 parts of compound nano-powders and 3 parts of antioxidants.

[0058] Among them, the preparation process of polyurethane elastomer is as follows:

[0059] A proper amount of hydroxy-terminated polybutadiene and toluene-2,4-diisocyanate were fully mixed in a mass ratio of 1:0.3, and treated at 84° C. for 25 minutes to obtain a first prepolymer;

[0060] A proper amount of polyhydroxy polybutadiene and toluene-2,4-diisocyanate were fully mixed in a mass ratio of 1:0.3, and treated at 84° C. for 25 minutes to obtain a second prepolymer;

[0061] A proper amount of polyoxypropylene glycol and toluene-2,4-diisocyanate were fully mixed in a mass ratio of 1:0.3, and treated at 84° C. for 25 minutes to obtain a third prepolymer;

[0062] The first prepolymer, the second prepolymer and the third prepolymer were fully mixed to obtain a mixed prepolymer, and 1,4-cyclohexanedimethanol and dibutyltin dilaurate were added to continue mixing. After injection molding, the prepolymer was placed in an oven at 100° C. for aging for 195 minutes to obtain a polyurethane elastomer.

[0063] Furthermore, the mass ratio of the added amounts of the first prepolymer, the second prepolymer and the third prepolymer in the mixed prepolymer is 1:0.4:0.6.

[0064] The addition amounts of 1,4-cyclohexanedimethanol and dibutyltin dilaurate were 0.023% and 0.034% of the mixed prepolymer mass, respectively.

[0065] In addition, the preparation process of the functional additive is as follows:

[0066] The base material was placed in an appropriate amount of γ-aminopropyltriethoxysilane at a solid-liquid ratio of 0.07 g / mL and mixed thoroughly, and then 0.3% of the base material mass of diatomaceous earth was added thereto, and the mixture was treated at 85°C and 110 r / min for 22 minutes;

[0067] After filtration, the product was washed three times with anhydrous ethanol and deionized water respectively, and dried at 75° C. to constant weight to obtain a functional additive.

[0068] Further, the preparation process of the base material is as follows:

[0069] Place water glass in an appropriate amount of 65% hydrochloric acid solution at a mass ratio of 0.07:1, mix thoroughly, treat at 25°C for 25 minutes, add deionized water with a mass of 135% of the hydrochloric acid solution, treat at 100 r / min for 25 minutes, and obtain a modified solution;

[0070] The nano-muscovite powder was placed in a proper amount of modified liquid at a solid-liquid ratio of 0.27 g / mL, treated at 55° C. for 55 min, filtered, and dried at 75° C. to constant weight to obtain a base material.

[0071] In this embodiment, it should be noted that water glass was purchased from Shandong Jinjuwang Chemical Co., Ltd., and nano-muscovite powder was purchased from Lingshou County Huajing Mica Co., Ltd.

[0072] Wherein, the vulcanizing agent is tert-butyl perbenzoate.

[0073] Antioxidant 1076 was selected as the antioxidant.

[0074] The compound nano powder is prepared by compounding nano titanium dioxide and nano zinc oxide in a mass ratio of 1:0.7.

[0075] In addition, this embodiment also provides a method for preparing the above-mentioned high temperature resistant polyurethane sealing ring, comprising the following steps:

[0076] Step 1: accurately weigh the polyurethane elastomer, functional additives, vulcanizing agent, nano-carbon fiber, compounded nano-powder and antioxidant, and put the polyurethane elastomer, functional additives, vulcanizing agent, nano-carbon fiber, compounded nano-powder and antioxidant into a mixing device for mixing and stirring;

[0077] Step 2: After the mixture is evenly mixed, the mixture is transferred into a mixer and subjected to a refining process at a temperature of 155°C;

[0078] Step 3: The kneaded mixture is then transferred to a vulcanization device for vulcanization treatment, and then formed by a hot pressing molding machine. The final product is a high-temperature resistant polyurethane sealing ring; wherein the vulcanization treatment pressure is 6MPa, the temperature is 155°C, and the vulcanization time is set to 40min; the molding temperature of the hot pressing molding machine is 180°C.

[0079] Example 3

[0080] The preparation method of the high temperature resistant polyurethane sealing ring provided in this embodiment is basically the same as that in embodiment 1, except that: the specific raw material composition and the specific preparation method of the high temperature resistant polyurethane sealing ring in this embodiment are different; the specific raw material composition and the specific preparation method of the high temperature resistant polyurethane sealing ring in this embodiment are as follows:

[0081] A high-temperature resistant polyurethane sealing ring is composed of the following raw materials in parts by weight: 40 parts of polyurethane elastomer, 6 parts of functional additives, 5 parts of vulcanizing agents, 4 parts of nano-carbon fibers, 7 parts of compound nano-powders and 5 parts of antioxidants.

[0082] Among them, the preparation process of polyurethane elastomer is as follows:

[0083] A proper amount of hydroxy-terminated polybutadiene and toluene-2,4-diisocyanate were fully mixed in a mass ratio of 1:0.5, and treated at 86° C. for 30 minutes to obtain a first prepolymer;

[0084] A proper amount of polyhydroxy polybutadiene and toluene-2,4-diisocyanate were fully mixed at a mass ratio of 1:0.5, and treated at 86° C. for 30 minutes to obtain a second prepolymer;

[0085] A proper amount of polyoxypropylene glycol and toluene-2,4-diisocyanate were fully mixed in a mass ratio of 1:0.5, and treated at 86° C. for 30 minutes to obtain a third prepolymer;

[0086] The first prepolymer, the second prepolymer and the third prepolymer were fully mixed to obtain a mixed prepolymer, and 1,4-cyclohexanedimethanol and dibutyltin dilaurate were added to continue mixing. After injection molding, the prepolymer was placed in an oven at 100° C. for aging for 200 minutes to obtain a polyurethane elastomer.

[0087] Furthermore, the mass ratio of the added amounts of the first prepolymer, the second prepolymer and the third prepolymer in the mixed prepolymer is 1:0.5:0.7.

[0088] The addition amounts of 1,4-cyclohexanedimethanol and dibutyltin dilaurate were 0.036% and 0.046% of the mass of the mixed prepolymer, respectively.

[0089] In addition, the preparation process of the functional additive is as follows:

[0090] The base material was placed in an appropriate amount of γ-aminopropyltriethoxysilane at a solid-liquid ratio of 0.12 g / mL and mixed thoroughly, and then 0.4% of the base material mass of diatomaceous earth was added thereto, and the mixture was treated at 90°C and 120 r / min for 25 min;

[0091] After filtration, the product was washed four times with anhydrous ethanol and deionized water respectively, and dried at 80° C. to constant weight to obtain a functional additive.

[0092] Further, the preparation process of the base material is as follows:

[0093] Place water glass in an appropriate amount of 70% hydrochloric acid solution at a mass ratio of 0.12:1, mix thoroughly, treat at 30°C for 30 minutes, add deionized water with a mass of 150% of the hydrochloric acid solution, treat at 120r / min for 30 minutes, and obtain a modified solution;

[0094] The nano-muscovite powder is placed in a proper amount of modified liquid at a solid-liquid ratio of 0.32 g / mL, treated at 60° C. for 50-60 min, filtered, and dried at 80° C. to constant weight to obtain a base material.

[0095] In this embodiment, it should be noted that water glass was purchased from Shandong Jinjuwang Chemical Co., Ltd., and nano-muscovite powder was purchased from Lingshou County Huajing Mica Co., Ltd.

[0096] Among them, the vulcanizing agent is di-2,5-hexane.

[0097] The antioxidant used is antioxidant CA.

[0098] The compound nano powder is compounded by nano titanium dioxide and nano zinc oxide in a mass ratio of 1:0.8.

[0099] In addition, this embodiment also provides a method for preparing the above-mentioned high temperature resistant polyurethane sealing ring, comprising the following steps:

[0100] Step 1: accurately weigh the polyurethane elastomer, functional additives, vulcanizing agent, nano-carbon fiber, compounded nano-powder and antioxidant, and put the polyurethane elastomer, functional additives, vulcanizing agent, nano-carbon fiber, compounded nano-powder and antioxidant into a mixing device for mixing and stirring;

[0101] Step 2: After the mixture is evenly mixed, the mixture is transferred into a mixer and subjected to a refining process at a temperature of 160°C;

[0102] Step 3: The kneaded mixture is then transferred to a vulcanization device for vulcanization treatment, and then formed by a hot pressing molding machine. The final product is a high-temperature resistant polyurethane sealing ring; wherein the vulcanization treatment pressure is 8 MPa, the temperature is 160°C, and the vulcanization time is set to 50 minutes; the molding temperature of the hot pressing molding machine is 190°C.

[0103] Comparative Example 1: The difference from Example 1 is that an equal amount of the first prepolymer is used to replace the polyurethane elastomer in this example.

[0104] Comparative Example 2: The difference from Example 1 is that in this example, an equal amount of a second prepolymer is used to replace the polyurethane elastomer.

[0105] Comparative Example 3: The difference from Example 1 is that an equal amount of nano-muscovite powder is used to replace the polyurethane elastomer in this example.

[0106] Comparative Example 4: The difference from Example 1 is that in this example, an equal amount of a third prepolymer is used to replace the functional additive.

[0107] Performance test: The high temperature resistant polyurethane sealing ring samples provided in Examples 1 to 3 and Comparative Examples 1 to 4 are marked as Examples 1 to 3 and Comparative Examples 1 to 4, respectively; and the relevant properties of the high temperature resistant polyurethane sealing rings provided in Examples 1 to 3 and Comparative Examples 1 to 4 are tested as follows:

[0108] 1. Thermal aging test: The test method is GB3512-2001 (aging conditions: 200°C, 160h).

[0109] 2. Flame retardant test: The test method is GB / T2406.2-2009.

[0110] The obtained test data are recorded in Table 1 and Table 2 below:

[0111] Table 1 Thermal aging performance test results of each group

[0112] Group Tensile strength before aging (MPa) Tensile strength after aging (MPa) Example 1 Group 19.5 18.4 Example 2 Group 19.2 18.5 Example 3 Group 19.4 18.5 Comparison group 1 17.8 15.7 Comparison of 2 groups 17.9 15.8 Comparison of 3 groups 18.2 16.1 Comparison of 4 groups 17.2 15.3

[0113] Table 2 Flame retardant performance test results of each group

[0114] Group Limiting oxygen index (%) Example 1 Group 43 Example 2 Group 42 Example 3 Group 42 Comparison group 1 37 Comparison of 2 groups 38 Comparison of 3 groups 35 Comparison of 4 groups 31

[0115] By comparing and analyzing the relevant data in Table 1 and Table 2, it can be seen that the high temperature resistant polyurethane sealing ring prepared by the present invention not only has good mechanical properties, but also has excellent heat resistance and flame retardancy, which effectively guarantees its quality. This shows that the high temperature resistant polyurethane sealing ring and the preparation method thereof provided by the present invention have a broader market prospect and are more suitable for promotion.

[0116] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0117] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A high temperature resistant polyurethane sealing ring, characterized in that: The invention is composed of the following raw materials in parts by weight: 30 to 40 parts of polyurethane elastomer, 3 to 6 parts of functional additives, 3 to 5 parts of vulcanizing agents, 2 to 4 parts of nano carbon fibers, 4 to 7 parts of compound nano powders and 2 to 5 parts of antioxidants; The preparation process of the polyurethane elastomer is as follows: A proper amount of hydroxy-terminated polybutadiene and toluene-2,4-diisocyanate are fully mixed in a mass ratio of 1:0.2-0.5, and treated at 82-86° C. for 20-30 minutes to obtain a first prepolymer; A suitable amount of polyhydroxy polybutadiene and toluene-2,4-diisocyanate are fully mixed in a mass ratio of 1:0.2-0.5, and treated at 82-86° C. for 20-30 minutes to obtain a second prepolymer; A proper amount of polyoxypropylene glycol and toluene-2,4-diisocyanate are fully mixed in a mass ratio of 1:0.2-0.5, and treated at 82-86° C. for 20-30 minutes to obtain a third prepolymer; The first prepolymer, the second prepolymer and the third prepolymer are fully mixed to obtain a mixed prepolymer, 1,4-cyclohexanedimethanol and dibutyltin dilaurate are added and mixed continuously, and after injection molding, the prepolymer is placed in an oven at 100° C. for aging for 190 to 200 minutes to obtain a polyurethane elastomer; The mass ratio of the first prepolymer, the second prepolymer and the third prepolymer added in the mixed prepolymer is 1:0.3-0.5:0.5-0.7; The preparation process of the functional additive is as follows: The base material is placed in an appropriate amount of γ-aminopropyltriethoxysilane at a solid-liquid ratio of 0.02-0.12 g / mL and fully mixed, and then 0.2-0.4% of diatomaceous earth by weight of the base material is added thereto, and the mixture is treated at 80-90°C and 100-120 r / min for 20-25 minutes; After filtration, the mixture is washed with anhydrous ethanol and deionized water for 2 to 4 times respectively, and dried at 70 to 80° C. to a constant weight to obtain a functional additive; The preparation process of the base material is as follows: Place water glass in an appropriate amount of 60-70% hydrochloric acid solution at a mass ratio of 0.02-0.12:1, mix thoroughly, treat at 20-30°C for 20-30 minutes, add deionized water with a mass of 120-150% of the hydrochloric acid solution, treat at 80-120 r / min for 20-30 minutes, and obtain a modified solution; The nano-muscovite powder is placed in a proper amount of modified liquid at a solid-liquid ratio of 0.22-0.32 g / mL, treated at 50-60° C. for 50-60 minutes, filtered, and dried at 70-80° C. to constant weight to obtain a base material.

2. A high temperature resistant polyurethane sealing ring according to claim 1, characterized in that: The added amounts of 1,4-cyclohexanedimethanol and dibutyltin dilaurate are 0.012-0.036% and 0.022-0.046% of the mass of the mixed prepolymer, respectively.

3. A high temperature resistant polyurethane sealing ring according to claim 1, characterized in that: The vulcanizing agent is selected from any one of di-2,5-hexane and tert-butyl perbenzoate.

4. A high temperature resistant polyurethane sealing ring according to claim 1, characterized in that: The antioxidant is selected from any one of antioxidant 1010, antioxidant 1076, and antioxidant CA.

5. A high temperature resistant polyurethane sealing ring according to claim 1, characterized in that: The compound nano powder is compounded by nano titanium dioxide and nano zinc oxide in a mass ratio of 1:0.6-0.

8.

6. A method for preparing a high temperature resistant polyurethane sealing ring according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1: accurately weigh the polyurethane elastomer, functional additives, vulcanizing agent, nano-carbon fiber, compounded nano-powder and antioxidant, and put the polyurethane elastomer, functional additives, vulcanizing agent, nano-carbon fiber, compounded nano-powder and antioxidant into a mixing device for mixing and stirring; Step 2: After the mixture is evenly mixed, the mixture is transferred into a mixer and subjected to a refining process at a temperature of 150 to 160°C; Step 3: The mixed mixture is then transferred to a vulcanization device for vulcanization treatment, and then formed by a hot pressing molding machine. The final product is a high-temperature resistant polyurethane sealing ring. The vulcanization treatment pressure is 5-8 MPa, the temperature is 150-160°C, and the vulcanization time is set to 30-50 min. The molding temperature of the hot pressing molding machine is 170-190°C.