A method for preparing a low temperature resistant composition

Abstract

The application provides a phenyl mixing rubber composition, which comprises a diphenyl vinyl silicone rubber, fumed silica and a hydroxyl silicone oil, and optionally further comprises one or both of diphenylsilanediol and diphenyldiethoxysilane. The phenyl mixing rubber composition has excellent low-temperature resistance and low-temperature recovery, TR10 is less than or equal to -100 DEG C, and a low-temperature compression coefficient is greater than or equal to 0.2. A sealing material prepared from the phenyl mixing rubber composition can solve the sealing problem in a severe low-temperature environment, and potential application fields of the sealing material include hydrogen energy storage tank sealing, aviation sealing, aerospace sealing and the like.

Description

TECHNICAL FIELD

[0001] The present invention belongs to the field of silicone, and relates to a low-temperature-resistant silicone rubber sealing material. BACKGROUND

[0002] Methyl vinyl silicone rubber has excellent low-temperature resistance and is applied in the fields of automobiles, medical treatment, consumer goods, etc., but cannot meet the conditions of more severe low-temperature environments. For example, the sealing material for a high-pressure hydrogen container (CHG tank) for fuel cells needs to meet the conditions of low-temperature retraction temperature TR10 < -75℃, etc. in addition to being able to withstand a pressure change of 0-70 MPa.

[0003] Patent application CN101605862A "Sealing material for high-pressure hydrogen container and high-pressure hydrogen container" discloses a high-strength sealing material with no obvious loss of low-temperature resistance, which is a phenyl silicone rubber and further includes one or more components such as ethylene-propylene-diene rubber, ethylene-propylene rubber, natural rubber, etc. The examples of the patent application claim that the material can maintain durability in a high-pressure hydrogen pressure change environment of 70 MPa or more, has a low-temperature retraction temperature TR10 < -75℃, and has good resistance to collapse. Since the material contains rubber components such as ethylene-propylene-diene rubber, which has a glass transition temperature of -40℃ to -60℃, the low-temperature retraction temperature of the final phenyl silicone rubber obtained can be at most about -75℃.

[0004] TR10 refers to stretching a test sample at a standard laboratory temperature, and then cooling to a sufficiently low temperature at which no retraction occurs when the stretching force is removed. The stretching force is removed, and the temperature is raised at a uniform rate. The temperature at which 10% retraction is reached is measured, and this temperature is TR10. The lower the temperature value of the test result, the better the low-temperature recovery performance after stretching. SUMMARY

[0005] The purpose of the present invention is to solve the sealing problem in a severe low-temperature environment by designing a phenyl rubber composition as a sealing material. The potential application fields of the sealing material include hydrogen energy storage tank sealing, aviation sealing, aerospace sealing, etc.

[0006] A phenyl rubber composition, which includes:

[0007] (1) a bisphenyl vinyl silicone rubber having the chemical formula (I), wherein R is independently a methyl group or a vinyl group, n1, n2 and n3 represent the degree of polymerization, the vinyl molar content of the bisphenyl vinyl silicone rubber is 0.03-1.0%, the phenyl molar content is 3-12%, and the molecular weight is 0.5-0.75 million;

[0008] (2) fumed silica;

[0009] (3) a hydroxy silicone oil of formula (II), Wherein, R1 is independently methyl or hydroxyl, R2 is independently phenyl or methyl, m1 and m2 represent the degree of polymerization, the hydroxyl molar content of the hydroxy silicone oil is 6-10%, and the viscosity at 25°C is 25-85 mm 2 / s;

[0010] Or the composition further contains:

[0011] (4) one or both of diphenylsilanediol and diphenyldiethoxysilane;

[0012] and / or,

[0013] (5) Silicone rubber anti-aging additives.

[0014] According to the present invention, the molar vinyl content of component (1) is 0.03-1.0%, for example: 0.03%, 0.05%, 0.08%, 0.14%, 0.18%, 0.22%, 0.30%, 0.40%, 0.50%, 0.60%, 0.70%, 0.80%, 0.90%, 1.0%, etc. In some embodiments of the present invention, the molar vinyl content of component (1) is 0.03-0.30%, for example: 0.03%, 0.05%, 0.08%, 0.14%, 0.18%, 0.22%, 0.30%, etc.

[0015] According to the present invention, the molar content of phenyl in component (1) is 3-12%, for example: 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, etc. In some embodiments of the present invention, the molar content of phenyl in component (1) is 3.5-10.5%, for example: 4%, 5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 10%, etc. In some preferred embodiments of the present invention, the molar content of phenyl in component (1) is 6.5-7.5%.

[0016] According to the present invention, the molecular weight of component (1) is 500,000-750,000, for example, 550,000, 560,000, 570,000, 580,000, 590,000, 600,000, 610,000, 620,000, 630,000, 640,000, 650,000, 660,000, 670,000, 680,000, 690,000, 700,000, 710,000, 720,000, 730,000, 740,000, 750,000, etc. In some embodiments of the present invention, the molecular weight of component (1) is 590,000-750,000, for example, 600,000, 610,000, 620,000, 630,000, 640,000, 650,000, 660,000, 670,000, 680,000, 690,000, 700,000, 710,000, 720,000, 730,000, 740,000, 750,000, etc. In some preferred embodiments of the present invention, the molecular weight of component (1) is 690,000-740,000.

[0017] According to the present application, component (1) can be a single substance of bisphenyl vinyl silicone rubber having formula (I), or alternatively, a mixture of bisphenyl vinyl silicone rubbers having formula (I). In some embodiments of the present application, component (1) is a mixture of two bisphenyl vinyl silicone rubbers having formula (I), wherein one bisphenyl vinyl silicone rubber has a vinyl molar content of 0.03-0.1%, a phenyl molar content of 3-12%, and a molecular weight of 0.5-0.75 million, and the other bisphenyl vinyl silicone rubber has a vinyl molar content of 0.15-0.2%, a phenyl molar content of 3-12%, and a molecular weight of 0.5-0.75 million; preferably the mass ratio of the two bisphenyl vinyl silicone rubbers is 1.5:1 to 1:1.

[0018] According to the present application, component (2) is added in a mass of 10%-53% of the mass of component (1), for example: 10%, 15%, 20%, 25%, 30%, 35%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, etc. In some embodiments of the present application, component (2) is added in a mass of 40%-45% of the mass of component (1), for example: 40%, 41%, 42%, 43%, 44%, 45%, etc.

[0019] According to the present application, the BET specific surface area of the fumed silica is 100-300 m 2 / g, for example 110 m 2 / g, 120 m 2 / g, 130 m 2 / g, 140 m 2 / g, 150 m 2 / g, 160 m 2 / g, 170 m 2 / g, 180 m 2 / g, 190 m 2 / g, 200 m 2 / g, 210 m 2 / g, 220 m 2 / g, 230 m 2 / g, 240 m 2 / g, 250 m 2 / g, 260 m 2 / g, 270 m 2 / g, 280 m 2 / g, 290 m 2 / g, 300 m 2 / g, etc. In some embodiments of the present application, the BET specific surface area of the fumed silica is 140-260 m 2 / g, for example 140 m 2 / g, 150 m 2 / g, 160 m 2 / g, 170 m 2 / g, 180 m 2 / g, 190 m 2 / g, 200 m 2 / g, 210 m 2 / g, 220 m 2 / g, 230 m 2 / g, 240 m 2 / g, 250 m 2 / g, 260 m 2 / g, etc.

[0020] According to the present application, component (2) can be a fumed silica having a single BET surface area, or alternatively, a mixture of several fumed silicas having different BET surface areas. In some embodiments of the present application, component (2) is a mixture of one or more of a fumed silica having a BET surface area of 150 m 2 / g, a fumed silica having a BET surface area of 200 m 2 / g, a fumed silica having a BET surface area of 250 m 2 / g, and a fumed silica having a BET surface area of 260 m

[0021] According to the present application, component (3) is added in an amount of 4.5% to 16% by mass of component (2), such as 4.7%, 5%, 5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5%, 9.0%, 9.5%, 10.0%, 10.5%, 11.0%, 11.5%, 12.0%, 12.5%, 13.0%, 13.5%, 14.0%, 14.5%, 15.0%, 15.5%, 16%, etc. In some embodiments of the present application, component (3) is added in an amount of 4.5% to 10% by mass of component (2), such as 4.7%, 5%, 5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5%, 9.0%, 9.5%, 10.0%, etc.

[0022] According to the present application, if further comprising component (4), namely, one or both of diphenylsilanediol and diphenyldiethoxysilane, component (4) is added in an amount of 1% to 5% by mass of component (2), such as 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, 5.0%, etc.

[0023] In some preferred embodiments of the present application, the composition contains component (3) and component (4), the mass of component (3) is 4.5% to 10% of the mass of component (2), the mass of component (4) is 1 to 5% of the mass of component (2), and the sum of the mass of component (3) and component (4) is 9 to 11% of the mass of component (2).

[0024] According to the present application, if further containing component (5), the addition amount of component (5) is 0.5 to 4% of the total mass of components (1), (2), (3) and (4), for example, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0% and the like. Various anti-aging aids known in the art can be selected, for example: cerium oxide, iron oxide, lanthanum oxide, titanium oxide and the like.

[0025] The present application also provides a method for preparing the aforementioned phenyl rubber composition, comprising: adding component (1), component (2), component (3) and optionally containing component (4) into a mixing device, and mixing under inert gas protection.

[0026] According to the present application, component (2) can be added at one time or in several times, and is preferably added in several times. In an embodiment of the present application, one seventh to three sevenths of component (2) is first added for mixing, and then the remaining component (2) is added in 2 to 4 times, and mixing is performed after each addition of component (2).

[0027] According to the present application, the preferred mixing device is a kneader, and various types and models of kneaders known in the art can be used.

[0028] According to the present application, the mixture after mixing can be continuously mixed at room temperature for 0.3 to 1.5 hours, or continuously mixed under heating for 0.5 to 2 hours. Preferably, the mixture is continuously mixed under heating for 0.5 to 2 hours, and preferably, the mixing under heating is performed under negative pressure. More preferably, the heating is performed in stages.

[0029] In an embodiment of the present application, the preparation method comprises:

[0030] In an embodiment of the present application, the preparation method comprises:

[0031] In one embodiment of the present application, the preparation method comprises:

[0032] In a kneader, component (1), one-seventh to three-sevenths of component (2), component (3) and optionally contained component (4) are added and mixed under inert gas protection; after uniform mixing, the remaining component (2) is added in 2-4 times, and after each addition of component (2), it is uniformly mixed; under inert gas protection, the temperature is gradually increased to 60-80℃, the temperature is maintained, and stirring is performed for 0.4-1 hour, then the temperature is gradually increased to 115-125℃, vacuum is drawn, the vacuum degree is -0.10 MPa to -0.01 MPa, and after the temperature is gradually increased to 150-160℃, it is maintained for 0.5-1.5 hours.

[0033] In one embodiment of the present application, the preparation method comprises:

[0034] In a kneader, component (1), one-seventh to three-sevenths of component (2), component (3) and optionally contained component (4) are added and mixed under inert gas protection; after uniform mixing, the remaining component (2) is added in 2-4 times, and after each addition of component (2), it is uniformly mixed; under inert gas protection, the temperature is gradually increased to 60-80℃, the temperature is maintained, and stirring is performed for 0.4-1 hour, then the temperature is gradually increased to 115-125℃, vacuum is drawn, the vacuum degree is -0.10 MPa to -0.01 MPa, and after the temperature is gradually increased to 150-160℃, it is maintained for 0.5-1.5 hours.

[0035] According to the present application, the preparation method further comprises the operation steps of finally cooling the obtained rubber compound to room temperature, discharging, and filtering.

[0036] The present application also provides a phenyl rubber compound composition prepared by the above preparation method.

[0037] The phenyl rubber compound composition obtained by the present application has excellent low-temperature resistance and low-temperature recovery, and the preferred composition has excellent performance of TR10≤-100℃ and low-temperature compression coefficient≥0.2.

[0038] The present application also provides a sealing composition comprising the aforementioned phenyl rubber compound composition of the present application and a vulcanizing agent. The vulcanizing agent can be a vulcanizing agent known in the art, such as 2,5-dimethyl-2,5-bis(tert-butyl peroxy)hexane.

[0039] In the present application, the viscosity test method is carried out according to the capillary method in GB / T 10247-2008, and a Ubbelohde viscometer is used at 25℃. DETAILED DESCRIPTION

[0040] Equipment and instruments: kneader, filter, tensile strength tester, specific gravity meter, low-temperature compression coefficient tester, temperature retraction tester

[0041] Reagents used:

[0042] (1) Phenyl vinyl silicone rubber: one or more having vinyl molar content of 0.08% and 0.18% respectively, phenyl content varying from 0 to 10 mol%, and molecular weight of 600 to 730 thousand;

[0043] (2) Fumed nano-silica: BET specific surface area of 200 m 2 / g

[0044] (3) Hydroxyl silicone oil (viscosity of 30 to 40 mm 2 / s at 25°C, hydroxyl content of 5%), diphenylsilanediol

[0045] Example 1

[0046] Put 55 parts of methyl vinyl silicone rubber having vinyl molar fraction of 0.08% and molecular weight of 600 thousand, 45 parts of methyl vinyl silicone rubber having vinyl molar fraction of 0.18% and molecular weight of 600 thousand into a kneader, and perform nitrogen passivation treatment on the kneader; add 12 parts by mass of fumed silica and 4 parts by mass of hydroxyl silicone oil into the kneader to mix and knead with the methyl vinyl silicone rubber, and after uniform mixing, add the remaining 30 parts by mass of silica in three times to mix uniformly, and after uniform mixing of all the silica, gradually increase the temperature, and throughout the process, protect with nitrogen, turn off the nitrogen, start vacuuming, and gradually increase the temperature to 160°C, and maintain for 1 hour, then release the vacuum, and switch to nitrogen protection; cool the obtained rubber compound to room temperature, discharge, and filter.

[0047] Example 2

[0048] Put 55 parts of methyl vinyl silicone rubber having vinyl molar fraction of 0.08% and molecular weight of 600 thousand, 45 parts of methyl vinyl silicone rubber having vinyl molar fraction of 0.18% and molecular weight of 600 thousand into a kneader, and perform nitrogen passivation treatment on the kneader; add 12 parts by mass of fumed silica and 4 parts by mass of hydroxyl silicone oil into the kneader to mix and knead with the methyl vinyl silicone rubber, and after uniform mixing, add the remaining 30 parts by mass of silica in three times to mix uniformly, and after uniform mixing of all the silica, gradually increase the temperature, and throughout the process, protect with nitrogen, turn off the nitrogen, start vacuuming, and gradually increase the temperature to 160°C, and maintain for 1 hour, then release the vacuum, and switch to nitrogen protection; cool the obtained rubber compound to room temperature, discharge, and filter.

[0049] Example 3

[0050] Put 55 parts of vinyl mole fraction 0.08% molecular weight MW of 600,000, phenyl content of 7 mol% of bisphenyl vinyl silicone rubber, 45 parts of vinyl mole fraction 0.18% molecular weight MW of 600,000, phenyl content of 7 mol% of bisphenyl vinyl silicone rubber into the kneader, and the kneader is treated with nitrogen passivation; 12 mass parts of fumed silica, 4 mass parts of hydroxyl silicone oil are added into the kneader to mix and knead with the silicone rubber, after mixing uniformly, the remaining 30 mass parts of silica is added again in 3 times to mix uniformly, after all the silica is mixed uniformly, gradually increase the temperature, the whole process is protected by nitrogen, close the nitrogen, start vacuumizing, vacuum degree-0.09Mpa, gradually increase the temperature to 160℃, and maintain for 1 hour, then unload the vacuum, and switch to nitrogen; The obtained rubber material is cooled to room temperature, discharged, and filtered.

[0051] Example 4

[0052] Put 55 parts of vinyl mole fraction 0.08% molecular weight MW of 600,000, phenyl content of 7 mol% of bisphenyl vinyl silicone rubber, 45 parts of vinyl mole fraction 0.18% molecular weight MW of 600,000, phenyl content of 7 mol% of bisphenyl vinyl silicone rubber into the kneader, and the kneader is treated with nitrogen passivation; 12 mass parts of fumed silica, 4 mass parts of hydroxyl silicone oil are added into the kneader to mix and knead with the silicone rubber, after mixing uniformly, the remaining 30 mass parts of silica is added again in 3 times to mix uniformly, after all the silica is mixed uniformly, gradually increase the temperature, the whole process is protected by nitrogen, close the nitrogen, start vacuumizing, vacuum degree-0.09Mpa, gradually increase the temperature to 160℃, and maintain for 1 hour, then unload the vacuum, and switch to nitrogen; The obtained rubber material is cooled to room temperature, discharged, and filtered.

[0053] Example 5

[0054] Put 55 parts of vinyl mole fraction 0.08% molecular weight MW of 600,000, phenyl content of 7 mol% of bisphenyl vinyl silicone rubber, 45 parts of vinyl mole fraction 0.18% molecular weight MW of 600,000, phenyl content of 7 mol% of bisphenyl vinyl silicone rubber into the kneader, and the kneader is treated with nitrogen passivation; 12 mass parts of fumed silica, 4 mass parts of hydroxyl silicone oil are added into the kneader to mix and knead with the silicone rubber, after mixing uniformly, the remaining 30 mass parts of silica is added again in 3 times to mix uniformly, after all the silica is mixed uniformly, gradually increase the temperature, the whole process is protected by nitrogen, close the nitrogen, start vacuumizing, vacuum degree-0.09Mpa, gradually increase the temperature to 160℃, and maintain for 1 hour, then unload the vacuum, and switch to nitrogen; The obtained rubber material is cooled to room temperature, discharged, and filtered.

[0055] Example 6

[0056] Put 55 parts of vinyl mole fraction 0.08% molecular weight MW 600,000, phenyl content of 7 mol% of monophenyl vinyl silicone rubber, 45 parts of vinyl mole fraction 0.18% molecular weight MW 600,000, phenyl content of 7 mol% of monophenyl vinyl silicone rubber into the kneader, and the kneader is treated with nitrogen passivation; 12 parts by mass of fumed silica, 4 parts by mass of hydroxyl silicone oil are added into the kneader to mix and knead with the silicone rubber, after mixing uniformly, the remaining 30 parts by mass of silica is added again in 3 times to mix uniformly, after all the silica is mixed uniformly, gradually increase the temperature, the whole process is protected by nitrogen, close the nitrogen, start vacuum, vacuum degree-0.09Mpa, gradually increase the temperature to 160℃, and maintain for 1 hour, then unload the vacuum, replace with nitrogen; The obtained rubber material is cooled to room temperature, discharged, filtered.

[0057] Example 7

[0058] Put 55 parts of vinyl mole fraction 0.08% molecular weight MW 600,000, phenyl content of 7 mol% of monophenyl vinyl silicone rubber, 45 parts of vinyl mole fraction 0.18% molecular weight MW 600,000, phenyl content of 7 mol% of monophenyl vinyl silicone rubber into the kneader, and the kneader is treated with nitrogen passivation; 12 parts by mass of fumed silica, 4 parts by mass of hydroxyl silicone oil are added into the kneader to mix and knead with the silicone rubber, after mixing uniformly, the remaining 30 parts by mass of silica is added again in 3 times to mix uniformly, after all the silica is mixed uniformly, gradually increase the temperature, the whole process is protected by nitrogen, close the nitrogen, start vacuum, vacuum degree-0.09Mpa, gradually increase the temperature to 160℃, and maintain for 1 hour, then unload the vacuum, replace with nitrogen; The obtained rubber material is cooled to room temperature, discharged, filtered.

[0059] Example 8

[0060] Put 55 parts of vinyl mole fraction 0.08% molecular weight MW 600,000, phenyl content of 7 mol% of monophenyl vinyl silicone rubber, 45 parts of vinyl mole fraction 0.18% molecular weight MW 600,000, phenyl content of 7 mol% of monophenyl vinyl silicone rubber into the kneader, and the kneader is treated with nitrogen passivation; 12 parts by mass of fumed silica, 4 parts by mass of hydroxyl silicone oil are added into the kneader to mix and knead with the silicone rubber, after mixing uniformly, the remaining 30 parts by mass of silica is added again in 3 times to mix uniformly, after all the silica is mixed uniformly, gradually increase the temperature, the whole process is protected by nitrogen, close the nitrogen, start vacuum, vacuum degree-0.09Mpa, gradually increase the temperature to 160℃, and maintain for 1 hour, then unload the vacuum, replace with nitrogen; The obtained rubber material is cooled to room temperature, discharged, filtered.

[0061] Example 9

[0062] Put 55 parts of vinyl mole fraction 0.08% molecular weight MW is 730,000, phenyl content is 7 mol% of double phenyl vinyl silicone rubber, 45 parts of vinyl mole fraction 0.18% molecular weight MW is 730,000, phenyl content is 7 mol% of double phenyl vinyl silicone rubber into the kneader, nitrogen passivation treatment is carried out to the kneader; 12 mass parts of fumed silica, 4 mass parts of hydroxyl silicone oil are added into the kneader and mixed with the silicone rubber, after mixing uniformly, the remaining 30 mass parts of silica is added again for 3 times and mixed uniformly, after all the silica is mixed uniformly, gradually increase the temperature, the whole process is protected by nitrogen, close the nitrogen, start vacuumizing, the vacuum degree is-0.09Mpa, gradually increase the temperature to 160℃, and maintain for 1 hour, then unload the vacuum, replace with nitrogen; the obtained rubber material is cooled to room temperature, discharged, filtered.

[0063] Example 10

[0064] Put 55 parts of vinyl mole fraction 0.08% molecular weight MW is 730,000, phenyl content is 7 mol% of double phenyl vinyl silicone rubber, 45 parts of vinyl mole fraction 0.18% molecular weight MW is 730,000, phenyl content is 7 mol% of double phenyl vinyl silicone rubber into the kneader, nitrogen passivation treatment is carried out to the kneader; 12 mass parts of fumed silica, 4 mass parts of hydroxyl silicone oil are added into the kneader and mixed with the silicone rubber, after mixing uniformly, the remaining 30 mass parts of silica is added again for 3 times and mixed uniformly, after all the silica is mixed uniformly, gradually increase the temperature, the whole process is protected by nitrogen, close the nitrogen, start vacuumizing, the vacuum degree is-0.09Mpa, gradually increase the temperature to 160℃, and maintain for 1 hour, then unload the vacuum, replace with nitrogen; the obtained rubber material is cooled to room temperature, discharged, filtered.

[0065] Example 11

[0066] Put 55 parts of vinyl mole fraction 0.08% molecular weight MW is 730,000, phenyl content is 7 mol% of double phenyl vinyl silicone rubber, 45 parts of vinyl mole fraction 0.18% molecular weight MW is 730,000, phenyl content is 7 mol% of double phenyl vinyl silicone rubber into the kneader, nitrogen passivation treatment is carried out to the kneader; 12 mass parts of fumed silica, 4 mass parts of hydroxyl silicone oil are added into the kneader and mixed with the silicone rubber, after mixing uniformly, the remaining 30 mass parts of silica is added again for 3 times and mixed uniformly, after all the silica is mixed uniformly, gradually increase the temperature, the whole process is protected by nitrogen, close the nitrogen, start vacuumizing, the vacuum degree is-0.09Mpa, gradually increase the temperature to 160℃, and maintain for 1 hour, then unload the vacuum, replace with nitrogen; the obtained rubber material is cooled to room temperature, discharged, filtered.

[0067] Example 12

[0068] Put 55 parts of vinyl mole fraction 0.08% of molecular weight MW of 700,000, phenyl content of 7 mol% of bisphenyl vinyl silicone rubber, 45 parts of vinyl mole fraction 0.18% of molecular weight MW of 700,000, phenyl content of 7 mol% of bisphenyl vinyl silicone rubber into the kneader, and the kneader is treated with nitrogen passivation; 12 parts by mass of fumed silica, 2 parts by mass of diphenyl silicone diol and 2 parts by mass of hydroxyl silicone oil are added into the kneader to mix and knead with the silicone rubber, after mixing uniformly, the remaining 30 parts by mass of silica is added in 3 times to mix uniformly, after all the silica is mixed uniformly, the temperature of the material is controlled at 60-80℃, stirring for 0.5 hours, the whole process is protected by nitrogen, heating, the temperature of the material is controlled at 120℃, nitrogen, start vacuum, vacuum degree-0.09Mpa, gradually heat to 155℃, and maintain for 1.5 hours, then release the vacuum, and switch to nitrogen; the obtained rubber material is cooled to room temperature, discharged, and filtered.

[0069] Example 13

[0070] Put 55 parts of vinyl mole fraction 0.08% of molecular weight MW of 700,000, phenyl content of 7 mol% of bisphenyl vinyl silicone rubber, 45 parts of vinyl mole fraction 0.18% of molecular weight MW of 700,000, phenyl content of 7 mol% of bisphenyl vinyl silicone rubber into the kneader, and the kneader is treated with nitrogen passivation; 12 parts by mass of fumed silica, 2 parts by mass of diphenyl silicone diol and 2 parts by mass of hydroxyl silicone oil are added into the kneader to mix and knead with the silicone rubber, after mixing uniformly, the remaining 30 parts by mass of silica is added in 3 times to mix uniformly, after all the silica is mixed uniformly, the temperature of the material is controlled at 60-80℃, stirring for 0.5 hours, the whole process is protected by nitrogen, heating, the temperature of the material is controlled at 120℃, nitrogen, start vacuum, vacuum degree-0.09Mpa, gradually heat to 155℃, and maintain for 1.5 hours, then release the vacuum, and switch to nitrogen; the obtained rubber material is cooled to room temperature, discharged, and filtered.

[0071] Test example

[0072] Performance test method: TR10 and low temperature compression coefficient are two kinds of low temperature performance test methods, the test method is carried out according to the method recorded in GB-T-7758-2020, HG-T-3866-2008.

[0073] TR10 principle: the sample is stretched at standard laboratory temperature, then cooled to a low enough temperature that does not appear to retract when the stretching force is removed. Remove the stretching force, and increase the temperature at a uniform rate. Measure the temperature at which 10% retraction rate is reached. The lower the test result temperature value, the better the low temperature recovery performance after stretching.

[0074] Low temperature compression coefficient principle: the sample is compressed to a certain height, then it is frozen in a certain low temperature environment for a specified time, and the recovery height after a period of time is measured after removing the compression load. The larger the test result value, the better the recovery, and the better the low temperature sealing performance.

[0075] Experimental results:

[0076] Table 1 Influence of phenyl silicone rubber structure on low temperature resistance

[0077]

[0078] As can be seen from Table 1, the structure of phenyl silicone rubber has a certain influence on low temperature resistance.

[0079] (1) 1#, 5#, 6# are single phenyl schemes without phenyl, different phenyl content, and the low temperature resistance coefficient is all <0.1, indicating that after removing the load, there is almost no recovery in the quantitative time, and the elasticity is lost;

[0080] (2) 2#, 3#, 4# are all double phenyl schemes, and with the increase of phenyl content, the low temperature resistance coefficient shows a trend of first increasing and then decreasing;

[0081] (3) 3#, 7#, 8#, 9# are all double phenyl schemes, and in the case of the same phenyl molar content, the molecular weight is different, and the results show that within a certain molecular weight, the higher the molecular weight of phenyl silicone rubber, the better the low temperature resistance.

[0082] Table 2 Influence of treating agent on low temperature resistance

[0083]

[0084] As can be seen from Table 2, the treating agent has a certain influence on low temperature resistance.

[0085] (1) The difference between 8#, 10#, 11# is the treating agent, and the scheme using only diphenyl silicone diol cannot be uniformly mixed, which may be because the melting point of the treating agent is too high, resulting in uneven dispersion in the system, and finally the fumed silica cannot be treated;

[0086] (2) 8#, 11# show that under the heat process, the low temperature resistance of the scheme treated by hydroxyl silicone oil and diphenyl silicone diol is better than that of the hydroxyl silicone oil alone.

[0087] Table 3 Influence of kneading process on low temperature resistance

[0088]

[0089] As can be seen from Table 3, the kneading process has a certain influence on low temperature resistance. In 11#, 12#, 13# system with 2% hydroxyl silicone oil and 2% diphenyl silicone diol as the treating agent, the two-stage heating process has the best low temperature resistance, which may be because the active hydroxyl groups on the surface of fumed silica are fully treated in situ under this process, so that fumed silica and phenyl silicone rubber and other additives are combined more fully.

Claims

1. A phenyl rubber compound composition, characterized in that Include: (1) Bisphenyl vinyl silicone rubber having the chemical formula (I), (I), wherein R is independently methyl or vinyl, n1, n2 and n3 represent the degree of polymerization, the vinyl molar content of the bisphenyl vinyl silicone rubber is 0.03-1.0%, the phenyl molar content is 3-12%, and the molecular weight is 500,000-750,000; component (1) is a mixture of two bisphenyl vinyl silicone rubbers having formula (I), wherein one bisphenyl vinyl silicone rubber has a vinyl molar content of 0.03-0.1%, a phenyl molar content of 3-12%, and a molecular weight of 500,000-750,000, and the other bisphenyl vinyl silicone rubber has a vinyl molar content of 0.15-0.2%, a phenyl molar content of 3-12%, and a molecular weight of 500,000-750,000; the mass ratio of the two bisphenyl vinyl silicone rubbers is 1.5:1 to 1:1; (2) Fumed silica; (3) a hydroxy silicone oil having the chemical formula (II), (II), wherein R1 is independently methyl or hydroxyl, R2 is independently phenyl or methyl, m1 and m2 represent the degree of polymerization, the hydroxyl molar content of the hydroxy silicone oil is 6-10%, and the viscosity at 25°C is 25-85 mm 2 / s; Optionally further contains: (4) one or both of diphenylsilanediol and diphenyldiethoxysilane; and / or, (5) Silicone rubber anti-aging additives; The mass of component (2) is 41% to 45% of the mass of component (1); the mass of component (3) is 4.5% to 10% of the mass of component (2); and the amount of component (4) optionally contained is 1 to 5% of the mass of component (2).

2. The phenyl rubber compound composition according to claim 1, wherein The composition contains component (3) and component (4), wherein the mass of component (3) is 4.5%-10% of the mass of component (2), the mass of component (4) is 1-5% of the mass of component (2), and the sum of the masses of component (3) and component (4) is 9-11% of the mass of component (2).

3. The phenyl rubber compound composition according to any one of claims 1 to 2, wherein The molar content of phenyl in component (1) is 6.5-7.5%, and the molecular weight is 690,000-740,000.

4. The phenyl rubber compound composition according to any one of claims 1 to 2, wherein The BET specific surface area of ​​fumed silica is 140-260 m 2 / g; or, Component (2) has a BET surface area of ​​150 m 2 / g, BET surface area 200 m 2 / g, BET surface area 250 m 2 / g of one or a mixture of two or more types of fumed silica.

5. The phenyl rubber compound composition according to any one of claims 1 to 2, wherein The amount of component (5) added is 0.5-4% of the total mass of components (1), (2), (3) and (4).

6. A method for preparing the phenyl rubber compound composition according to any one of claims 1 to 5, characterized in that include: Component (1), component (2), component (3) and optional component (4) are added to a mixing device and mixed under the protection of an inert gas.

7. The method according to claim 6, wherein: First, add one-seventh to three-sevenths of component (2) and mix, then add the remaining component (2) in 2-4 portions, mixing after each addition of component (2).

8. The method according to claim 6 or 7, wherein: The mixed mixture is further mixed at room temperature for 0.3-1.5 hours, or, under heating, for 0.5-2 hours.

9. The method according to claim 8, wherein Mixing under heating conditions is carried out under negative pressure conditions.

10. The method according to claim 8, wherein The heating is carried out in stages.

11. The preparation method according to claim 6, characterized in that include: Add component (1), one-seventh to three-sevenths of component (2), component (3) and optionally component (4) into a kneader and mix under the protection of an inert gas; after uniform mixing, add the remaining component (2) in 2-4 portions, mixing uniformly after each addition of component (2); continue stirring for another 0.3-1.5 hours under the protection of an inert gas; or, Add component (1), one-seventh to three-sevenths of component (2), component (3) and optionally component (4) into a kneader and mix under the protection of an inert gas; after uniform mixing, add the remaining component (2) in 2-4 portions, mixing uniformly after each addition of component (2); under the protection of an inert gas, gradually increase the temperature and simultaneously evacuate the mixture to a vacuum degree of -0.10 MPa to -0.01 MPa, raise the temperature to 150-170°C and maintain for 0.5-2 hours; or, Add component (1), one-seventh to three-sevenths of component (2), component (3) and optionally component (4) into a kneader and mix under the protection of an inert gas; after uniform mixing, add the remaining component (2) in 2-4 portions, and mix uniformly after each addition of component (2); under the protection of an inert gas, gradually heat to 60-80°C, maintain the temperature, stir for 0.4-1 hour, then gradually heat to 115-125°C, and then evacuate to a vacuum degree of -0.10 MPa to -0.01 MPa, gradually heat to 150-160°C and maintain for 0.5-1.5 hours.

12. A sealing composition comprising the phenyl rubber compound composition according to any one of claims 1 to 5 and a vulcanizing agent.

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