A hydrolysis-resistant and tear-resistant polyurethane sealing material and a preparation method thereof

Abstract

The present application relates to the technical field of polyurethane materials, and relates to a hydrolysis-resistant and tear-resistant polyurethane sealing material and a preparation method thereof. The polyurethane sealing material comprises polytetramethylene glycol, epoxidized terminal hydroxybutadiene, hydroxy-modified silicone oil, dimethoxyethyl phthalate, modified graphene oxide, an antioxidant, a chain extender, 2,4-toluene diisocyanate and an organic tin catalyst; the modified graphene oxide is prepared by grafting graphene oxide with an organic polymer, and the organic polymer is prepared by reacting 4-allylphenol, a vinyl silane coupling agent and styrene under the action of a free radical initiator; the polyurethane sealing material has the advantage of improving the tear resistance of the polyurethane sealing material.

Description

Technical Field

[0001] The present application relates to the technical field of polyurethane materials, and in particular to a hydrolysis-resistant and tear-resistant polyurethane sealing material and a preparation method thereof. Background Art

[0002] Polyurethane, or polyurethane, refers to a polymer containing carbamate groups in the main chain of the macromolecule. Polyurethane is divided into two categories: polyester polyurethane and polyether polyurethane. Polyester polyurethane is prepared with diisocyanate and hydroxyl-terminated polyester as raw materials; polyether polyurethane is prepared with diisocyanate and hydroxyl-terminated polyether as raw materials. Since the groups contained in the polyurethane macromolecule are all strong polar groups, and the macromolecule also contains polyether or polyester flexible segments, polyurethane has the advantages of high mechanical strength, oxidation stability, water resistance, oil resistance, etc., and its flexibility and resilience are high, making it possible to be used as an excellent sealing material. As a sealing material, it is widely used in various fields such as telecommunications cables, electronics, aerospace, petroleum, and automobiles, but in some special and high-demand insulation sealing and waterproofing material fields, higher sealing performance is required. However, during transportation or installation, polyurethane sealing rings are prone to cracks due to insufficient mechanical properties, thereby reducing their sealing properties. Summary of the invention

[0003] In order to improve the tear resistance of polyurethane sealing materials, the present application provides a hydrolysis-resistant and tear-resistant polyurethane sealing material and a preparation method thereof.

[0004] In a first aspect, the present application provides a hydrolysis-resistant and tear-resistant polyurethane sealing material, which adopts the following technical solution:

[0005] A hydrolysis-resistant and tear-resistant polyurethane sealing material comprises the following raw materials in parts by weight: 90-110 parts of polytetramethylene glycol, 8-12 parts of epoxidized terminal hydroxy butadiene, 3-7 parts of hydroxy-modified silicone oil, 20-30 parts of dimethoxyethyl phthalate, 0.005-0.015 parts of modified graphene oxide, 0.1-0.5 parts of antioxidant, 13-17 parts of chain extender, 28-32 parts of 2,4-toluene diisocyanate and 0.5-0.9 parts of organic tin catalyst;

[0006] The preparation method of the modified graphene oxide is as follows:

[0007] S1. Under nitrogen atmosphere, using DMF as solvent, add 8-12 parts by weight of 4-allylphenol, 90-110 parts by weight of a mixture of a vinyl silane coupling agent and styrene, stir until dissolved, then add 0.08-0.012 parts by weight of a free radical initiator, raise the temperature to 60-70° C., stir and react to obtain solution A;

[0008] S2. Add 0.8-1.2 parts by weight of graphene oxide to 45-55 parts by weight of DMF to obtain a graphene oxide dispersion, which is then added to solution A, and then a water-carrying agent is added, and 0.8-1.2 parts by weight of p-toluenesulfonic acid is added, the temperature is raised to 145-160° C., the reaction is stirred for 18-22 hours, the temperature is lowered, and the precipitate is filtered, and the precipitate is washed and dried to obtain modified graphene oxide.

[0009] By adopting the above technical scheme, by modifying graphene oxide through grafting polymer, on the one hand, the gap between graphene oxide molecules can be increased, thereby improving the dispersibility of graphene oxide; on the other hand, the polymer molecules prepared in the present application contain a large number of hydroxyl groups, benzene ring groups and organosilicon structures, and the hydroxyl groups contained can participate in the reaction of the polyurethane sealing material, increase the crosslinking density inside the system, and make the fusion between graphene oxide and the system; the benzene ring group can act on the cyclic structure in the graphene oxide molecule through the electron cloud, so that the polymer is attached to the surface of graphene oxide, thereby making the organic modification of graphene oxide stronger, and the organosilicon structure can greatly reduce the interfacial tension between it and the system, making it more compatible with the system, and the integrity of the polyurethane sealing material is stronger, so that the mechanical properties of graphene oxide can be fully exerted, and the tear resistance of the prepared polyurethane sealing material is excellent; the addition of hydroxyl-modified silicone oil can increase the crosslinking degree of the polyurethane sealing material, and can play the role of a softener to improve the resilience of the polyurethane sealing material; in addition, as an organosilicon compound, it can effectively prevent moisture from entering the system, thereby greatly improving the hydrolysis resistance of the polyurethane sealing material.

[0010] Preferably, the mass ratio of the vinyl silane coupling agent to the styrene is (5-9):3.

[0011] By adopting the above technical scheme, as the amount of vinyl silane coupling agent added decreases, the tearing properties of the polyurethane sealing material gradually decreases, indicating that the silicone structure contained in the polymer can promote the compatibility of graphene oxide and polyurethane materials, allowing the hydroxyl groups contained in the graphene oxide sheets to participate in the cross-linking of the system, thereby weakening the rigidity of graphene oxide, enhancing the toughness of the polyurethane sealing material and improving the tearing strength.

[0012] Preferably, the vinyl silane coupling agent is one or more of vinyl triethoxysilane, acryloxymethyl trimethoxysilane, 7-octenyl trimethoxysilane, γ-methacryloxypropyl trimethoxysilane, vinyl triisopropoxysilane and vinyl tributylidene oxime silane.

[0013] By adopting the above technical scheme, the modified graphene oxide with the same performance as the present application can be prepared by using the raw materials within this range of the vinyl silane coupling agent. Although not listed one by one in the embodiments, they can all be realized in principle.

[0014] Preferably, the water-carrying agent is n-butanol.

[0015] By adopting the above technical solution, n-butanol is safer and more environmentally friendly, and as a water-carrying agent, it can also make the normal phase reaction more complete.

[0016] Preferably, the free radical initiator is one or both of azobisisobutyronitrile and azobisisoheptanenitrile.

[0017] Preferably, the chain extender is a mixture of 2,2'-diallyl bisphenol A and 1,4-butanediol, and the mass ratio of 2,2'-diallyl bisphenol A to 1,4-butanediol is 1:1.

[0018] By adopting the above technical scheme, the chain extender adopts a mixture of 2,2'-diallyl bisphenol A and 1,4-butanediol. On the basis of participating in cross-linking, 2,2'-diallyl bisphenol A also has the functions of anti-aging and wear resistance, improving the toughness and heat resistance of polyurethane sealing materials, and can improve the tear resistance of polyurethane sealing materials.

[0019] Preferably, the organic tin catalyst is one or more of stannous octoate, dibutyltin dilaurate, dibutyltin diacetate, and organic tin catalyst T-21.

[0020] In a second aspect, the present application provides a method for preparing a hydrolysis-resistant and tear-resistant polyurethane sealing material, using the following technical solution:

[0021] A method for preparing a hydrolysis-resistant and tear-resistant polyurethane sealing material comprises the following steps:

[0022] S1. Mix polytetrahydrofuran ether diol, epoxidized terminal hydroxy butadiene, hydroxyl-modified silicone oil, dimethoxyethyl phthalate, modified graphene oxide and antioxidant, and stir at a high speed of more than 3000r / min for 20-40min; then add 2,4-toluene diisocyanate and 0.7kg of organic tin catalyst, stir and mix, heat to 75-85°C, react for 1.5-2.5h, and obtain a polyurethane prepolymer;

[0023] S2. Add a chain extender to the polyurethane prepolymer and mix to react. After reacting for 2-3 hours, cure the mixture at 103-115° C., demould after curing for 2-4 hours, and then vulcanize at 115-125° C. for 5-7 hours to obtain a polyurethane sealing material.

[0024] By adopting the above technical scheme, the preparation method of the present application is easy to operate, does not require special processes or equipment modifications, has a high tolerance for process parameters, has a high rate of qualified products, and is suitable for large-scale production.

[0025] In summary, the present application includes at least one of the following beneficial technical effects:

[0026] 1. By modifying graphene oxide by grafting polymer, on the one hand, the gap between graphene oxide molecules can be increased, thereby improving the dispersibility of graphene oxide; on the other hand, the polymer molecules prepared in the present application contain a large number of hydroxyl groups, benzene ring groups and organosilicon structures, and the hydroxyl groups contained can participate in the reaction of the polyurethane sealing material, increase the crosslinking density inside the system, and make the fusion between graphene oxide and the system; the benzene ring group can act on the cyclic structure in the graphene oxide molecule through the electron cloud, so that the polymer is attached to the surface of graphene oxide, thereby making the organic modification of graphene oxide stronger, and the organosilicon structure can greatly reduce the interfacial tension between it and the system, making it more compatible with the system, and the integrity of the polyurethane sealing material is stronger, so that the mechanical properties of graphene oxide can be fully exerted, and the tear resistance of the prepared polyurethane sealing material is excellent; the addition of hydroxyl-modified silicone oil can increase the crosslinking degree of the polyurethane sealing material, and can play the role of a softener to improve the resilience of the polyurethane sealing material; in addition, as an organosilicon compound, it can effectively prevent moisture from entering the system, thereby greatly improving the hydrolysis resistance of the polyurethane sealing material.

[0027] 2. The polyurethane sealing material prepared in the present application has excellent anti-hydrolysis and tearing properties, and its rebound performance is relatively good; wherein, the tensile strength of the polyurethane sealing material prepared in the present application is 43.2-50.7MPa, and the elongation at break is between 352.6-381.2%; and under the detection conditions of temperature of 70°C, relative humidity of 95%, and test cycle of 168h, its tensile strength retention rate is between 96.2-97.6%, and its elongation at break retention rate is between 99.8-102.7%; its tear strength is between 77.9-83.7MPa, and its rebound rate is maintained at 36.2-42.0%. DETAILED DESCRIPTION

[0028] The present application is further described in detail below in conjunction with the specific contents.

[0029] raw material

[0030] The raw materials used in the preparation examples and embodiments of this application were purchased from commercial sources. The graphene oxide had a thickness of about 1 nm, a number of layers of 1-2, an average diameter of 30 μm, and a specific surface area of ​​200 m 2 / g, purity>95wt%; the model of antioxidant is antioxidant 1010; the viscosity of hydroxyl modified silicone oil is 1000cst, and the hydroxyl content is 9%; the model of polytetramethylene ether diol is PTMEG1000, and the product grade is industrial grade.

[0031] Preparation Example 1

[0032] A modified graphene oxide, the preparation method of which is as follows:

[0033] S1. Under a nitrogen atmosphere, add 10 g of 4-allylphenol, 100 g of a mixture of 7-octenyltrimethoxysilane and styrene to 200 g of DMF, the mass ratio of 7-octenyltrimethoxysilane to styrene being 7:3, stir until dissolved, then add 0.01 g of azobisisobutyronitrile, heat to 65°C, stir and react for 15 h to obtain solution A;

[0034] S2. Add 1 g of graphene oxide to 50 g of DMF, stir for 20 min, and ultrasonically disperse for 10 min to obtain a graphene oxide dispersion, which is then added to solution A, and then 50 g of n-butanol is added as a water-carrying agent, and 1 g of p-toluenesulfonic acid is added as a catalyst. The temperature is raised to 150 ° C, and the reaction is stirred for 20 h. After cooling to room temperature, centrifugation is performed at a speed of 1200 r / min, and the supernatant is discarded. The precipitate is washed with DMF, and then with ethanol, and dried to obtain modified graphene oxide.

[0035] Preparation Example 2

[0036] A modified graphene oxide, which is different from Preparation Example 1 in that the mass ratio of 7-octenyltrimethoxysilane to styrene is 5:3, and the remaining steps are the same as Preparation Example 1.

[0037] Preparation Example 3

[0038] A modified graphene oxide, which is different from Preparation Example 1 in that the mass ratio of 7-octenyltrimethoxysilane to styrene is 9:3, and the remaining steps are the same as Preparation Example 1.

[0039] Example 1 A hydrolysis-resistant and tear-resistant polyurethane sealing material, the preparation method of which is as follows:

[0040] S1, 100kg of polytetrahydrofuran ether diol, 10kg of epoxidized terminal hydroxy butadiene, 5kg of hydroxy-modified silicone oil, 25kg of dimethoxyethyl phthalate, 0.01kg of modified graphene oxide and 0.1kg of antioxidant are mixed, and stirred at a high speed of 3000r / min for 30min; then 30kg of 2,4-toluene diisocyanate and 0.7kg of stannous octoate are added, and stirring and mixing are continued at a speed of 2000r / min, and the temperature is raised to 80°C. After reacting for 2h, a polyurethane prepolymer is obtained; wherein the modified graphene oxide comes from Preparation Example 1;

[0041] S2. Add 15 kg of chain extender to the polyurethane prepolymer for mixing reaction. The chain extender is a mixture of 2,2'-diallyl bisphenol A and 1,4-butanediol in a mass ratio of 1:1. After reacting for 2.5 hours, inject the mixture into a mold and cure it at 108°C. After curing for 3 hours, demold it and then vulcanize it at 120°C for 6 hours to obtain a hydrolysis-resistant and tear-resistant polyurethane sealing material.

[0042] Example 2 A hydrolysis-resistant and tear-resistant polyurethane sealing material, which is different from Example 1 in that the modified graphene oxide comes from Preparation Example 2, and the remaining steps are the same as those of Example 1.

[0043] Example 3 A hydrolysis-resistant and tear-resistant polyurethane sealing material, which is different from Example 1 in that the modified graphene oxide comes from Preparation Example 3, and the remaining steps are the same as those of Example 1.

[0044] Example 4 A hydrolysis-resistant and tear-resistant polyurethane sealing material, which is different from Example 1 in that the added amount of modified graphene oxide is 0.005 kg, and the remaining steps are the same as those of Example 1.

[0045] Example 5 A hydrolysis-resistant and tear-resistant polyurethane sealing material, which is different from Example 1 in that the added amount of modified graphene oxide is 0.015 kg, and the remaining steps are the same as those in Example 1.

[0046] Comparative Example 1

[0047] A hydrolysis-resistant and tear-resistant polyurethane sealing material, which is different from Example 1 in that its modified graphene oxide is replaced by graphene oxide of equal mass, and the remaining steps are the same as those of Example 1.

[0048] Comparative Example 2

[0049] A hydrolysis-resistant and tear-resistant polyurethane sealing material, which is different from Example 1 in that hydroxy-modified silicone oil is not added to its raw materials, and the remaining steps are the same as those of Example 1.

[0050] Comparative Example 3

[0051] A hydrolysis-resistant and tear-resistant polyurethane sealing material, which is different from Example 1 in that its chain extender is 1,4-butanediol, and the remaining steps are the same as those of Example 1.

[0052] Performance testing

[0053] Detection method / test method

[0054] Polyurethane sealing materials were prepared according to the preparation methods of Examples 1-5 and Comparative Examples 1-3, and then tested according to the following testing methods. The test results are shown in Table 1.

[0055] Tensile strength: tested according to the test method in GB / T 528-2009 (Type 2);

[0056] Elongation at break: Tested according to the test method in GB / T 528-2009 (Type 2);

[0057] Tear strength: Tested according to the test method in GB / T 529-2008 (right angle);

[0058] Hydrolysis resistance test: The conditions for the hydrolysis resistance test are: temperature 70°C, relative humidity 95%, and test period 168h;

[0059] Rebound rate: tested according to the test method in GB / T 1681-2009.

[0060] Table 1 Test results of Examples 1-5 and Comparative Examples 1-3

[0061]

[0062] It can be seen from Examples 1-5 and Comparative Examples 1-3, as well as the test data in Table 1, that the polyurethane sealing material prepared in the present application has excellent hydrolysis resistance and tear resistance, and its resilience performance is relatively good; wherein, the tensile strength of the polyurethane sealing material prepared in the present application is 43.2-50.7 MPa, and the elongation at break is 352.6-381.2%; and under the test conditions of a temperature of 70°C, a relative humidity of 95%, and a test period of 168h, the tensile strength retention rate is 96.2-97.6%, and the elongation at break retention rate is 99.8-102.7%; the tear strength is 77.9-83.7 MPa, and the resilience is maintained at 36.2-42.0%.

[0063] By modifying graphene oxide through grafting polymer, on the one hand, the gap between graphene oxide molecules can be increased, thereby improving the dispersibility of graphene oxide; on the other hand, the polymer molecules prepared in this application contain a large number of hydroxyl groups, benzene ring groups and organosilicon structures, and the hydroxyl groups contained can participate in the reaction of the polyurethane sealing material, increase the crosslinking density inside the system, and make the fusion between graphene oxide and the system; the benzene ring group can act on the cyclic structure in the graphene oxide molecule through the electron cloud, so that the polymer is attached to the surface of graphene oxide, thereby making the organic modification of graphene oxide stronger, and the organosilicon structure can greatly reduce the interfacial tension between it and the system, making it more compatible with the system, and the integrity of the polyurethane sealing material is stronger, so that the mechanical properties of graphene oxide are fully exerted, and the tear resistance of the obtained polyurethane sealing material is excellent. It can be seen from the test data of Example 1 and Comparative Example 1. Combined with the test data of Examples 2-3, it can be seen that with the decrease in the amount of 7-octenyltrimethoxysilane added, the tearing properties of the polyurethane sealing material gradually decreases, indicating that the silicone structure contained in the polymer can promote the compatibility of graphene oxide and the polyurethane material, so that the hydroxyl groups contained in the graphene oxide sheets can participate in the cross-linking of the system, thereby weakening the rigidity of graphene oxide, enhancing the toughness of the polyurethane sealing material and improving the tear strength.

[0064] It can be seen from the test data of Example 1 and Examples 4-5 that within this range, as the amount of modified graphene oxide added gradually increases, the tear strength and hydrolysis resistance of the polyurethane sealing material gradually improve. However, if the amount of modified graphene oxide added is too high, it is not conducive to the resilience and elongation at break of the polyurethane sealing material.

[0065] The addition of hydroxyl-modified silicone oil can improve the crosslinking degree of the polyurethane sealing material and can act as a softener to improve the resilience of the polyurethane sealing material; in addition, as an organic silicon compound, it can effectively prevent moisture from entering the system, thereby greatly improving the anti-hydrolysis performance of the polyurethane sealing material. This can be seen from the test data of Example 1 and Comparative Example 2.

[0066] The chain extender is a mixture of 2,2'-diallyl bisphenol A and 1,4-butanediol. 2,2'-diallyl bisphenol A not only participates in cross-linking, but also has the functions of anti-aging, wear resistance, and improving the toughness and heat resistance of the polyurethane sealing material. This can be seen from the test data of Example 1 and Comparative Example 3.

[0067] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A hydrolysis-resistant and tear-resistant polyurethane sealing material, characterized in that: The invention comprises the following raw materials in parts by weight: 90-110 parts of polytetramethylene glycol, 8-12 parts of epoxidized terminal hydroxy butadiene, 3-7 parts of hydroxy modified silicone oil, 20-30 parts of dimethoxyethyl phthalate, 0.005-0.015 parts of modified graphene oxide, 0.1-0.5 parts of antioxidant, 13-17 parts of chain extender, 28-32 parts of 2,4-toluene diisocyanate and 0.5-0.9 parts of organic tin catalyst; The preparation method of the modified graphene oxide is as follows: S1. Under nitrogen atmosphere, using DMF as solvent, add 8-12 parts by weight of 4-allylphenol, 90-110 parts by weight of a mixture of a vinyl silane coupling agent and styrene, stir until dissolved, then add 0.08-0.012 parts by weight of a free radical initiator, raise the temperature to 60-70° C., stir and react to obtain solution A; S2, adding 0.8-1.2 parts by weight of graphene oxide to 45-55 parts by weight of DMF to obtain a graphene oxide dispersion, then adding it to solution A, then adding a water-carrying agent, adding 0.8-1.2 parts by weight of p-toluenesulfonic acid, heating to 145-160° C., stirring to react for 18-22 hours, cooling, filtering, washing and drying the precipitate to obtain modified graphene oxide; The chain extender is a mixture of 2,2'-diallyl bisphenol A and 1,4-butanediol, and the mass ratio of 2,2'-diallyl bisphenol A to 1,4-butanediol is 1:1; The organic tin catalyst is one or more of stannous octoate, dibutyltin dilaurate, dibutyltin diacetate, and organic tin catalyst T-21.

2. The hydrolysis-resistant and tear-resistant polyurethane sealing material according to claim 1, characterized in that: The mass ratio of the vinyl silane coupling agent to the styrene is (5-9):

3.

3. The hydrolysis-resistant and tear-resistant polyurethane sealing material according to claim 1, characterized in that: The vinyl silane coupling agent is one or more of vinyl triethoxysilane, acryloxymethyl trimethoxysilane, 7-octenyl trimethoxysilane, γ-methacryloxypropyl trimethoxysilane, vinyl triisopropoxysilane and vinyl tributylidene oxime silane.

4. The hydrolysis-resistant and tear-resistant polyurethane sealing material according to claim 1, characterized in that: The water-carrying agent is n-butanol.

5. The hydrolysis-resistant and tear-resistant polyurethane sealing material according to claim 1, characterized in that: The free radical initiator is one or both of azobisisobutyronitrile and azobisisoheptanenitrile.

6. A method for preparing the hydrolysis-resistant and tear-resistant polyurethane sealing material according to any one of claims 1 to 5, characterized in that: It includes the following steps: S1. Mix polytetrahydrofuran ether diol, epoxidized terminal hydroxy butadiene, hydroxyl-modified silicone oil, dimethoxyethyl phthalate, modified graphene oxide and antioxidant, and stir at a high speed of more than 3000r / min for 20-40min; then add 2,4-toluene diisocyanate and 0.7kg of organic tin catalyst, stir and mix, heat to 75-85°C, react for 1.5-2.5h, and obtain a polyurethane prepolymer; S2. Add a chain extender to the polyurethane prepolymer and mix to react. After reacting for 2-3 hours, cure the mixture at 103-115° C., demould after curing for 2-4 hours, and then vulcanize at 115-125° C. for 5-7 hours to obtain a polyurethane sealing material.

Images