A high-temperature vulcanized silicone rubber and its preparation method

Abstract

This invention belongs to the field of organosilicon polymer technology, and discloses a high-temperature vulcanized silicone rubber and its preparation method. The formulation consists of the following raw materials: 100 parts of methyl vinyl silicone rubber raw rubber, 0.01-0.05 parts of a treatment agent, 0.003-0.007 parts of a catalyst, 0.8-2 parts of a vulcanizing agent, 0.1-0.5 parts of a crosslinking agent, and 45-55 parts of reinforcing fillers, etc. This invention, through a special combination of treatment agents and crosslinking agents, achieves the effect of improving the heat resistance and modulus of the high-temperature vulcanized rubber. The technical measures are simple and the effect is significant.

Description

Technical Field

[0001] This invention relates to the field of organosilicon polymer technology, and in particular to a high-temperature vulcanized silicone rubber and its preparation method. Background Technology

[0002] Silicone rubber possesses excellent high and low temperature resistance, weather resistance, and electrical insulation properties, making it widely used in machinery, electronics, chemical engineering, and aerospace industries. Due to the high bond energy of the Si-O bonds that make up the main chain of silicone rubber, it exhibits superior heat resistance compared to most rubbers. With continuous technological advancements, the requirements for the heat resistance of silicone rubber are further increasing.

[0003] The degradation of silicone rubber at high temperatures mainly involves breakage and rearrangement, and the main reaction occurring inside the molecule is the cyclization reaction. The known methods to improve the heat resistance of silicone rubber are: (1) introducing a large structure into the main chain of silicone rubber to prevent the cyclization degradation of the main chain of silicone rubber molecules. The introduction of this structure can increase the steric hindrance of the cyclization of the main chain of silicone rubber, thereby reducing the tendency of silicone rubber to become a low molecular weight cyclic compound; (2) improving the thermal stability of silicone rubber by introducing aromatic ring groups on the side groups (Liu Liping, Li Li, Huang Yanhua, et al. "Study on high and low temperature tensile properties of phenyl silicone rubber [J]". Organosilicon Materials, 2013, 27(3):185-188); (3) The heat resistance of silicone rubber can be improved by adding heat-resistant additives such as metal oxides and silicone resins (Li Chen, Sun Da, Liu Chunxia, ​​et al. "The effect of metal oxides on the heat resistance of heat-cured silicone rubber [J]". Organosilicon Materials, 2019, 33(3):166-170), (Jiang Jian, Zheng Zhimin, Xie Zemin. "The effect of hydrolytic stability of silazane additives on the thermal stability of silicone rubber [J]". Acta Polymerica Sinica, 2002(5):623-627). The above methods can effectively improve the heat resistance of silicone rubber within a certain range. Based on the above methods, it can be seen that the terminal hydroxyl groups play an important role in promoting the high-temperature pyrolysis of silicone rubber. Therefore, the effect of reducing the terminal hydroxyl groups in raw rubber molecules on improving the heat resistance of silicone rubber should not be underestimated, but there is insufficient literature on this aspect.

[0004] Silicone rubber has a very low modulus and undergoes significant deformation under slight stress, which greatly limits its application, especially under dynamic conditions. The modulus can be increased by adding mineral fibers or other materials to the compound (Zhao Min, "A Composite Material of Carbon Fiber and Silicone Rubber and Its Processing Method [P]", Patent Document CN101942202A), but this method inevitably reduces other properties of the silicone rubber.

[0005] Therefore, the research on a high-temperature vulcanized silicone rubber and its preparation method is of great significance, enabling the production of high-temperature vulcanized silicone rubber with good heat resistance and high modulus through a simple formulation and preparation method. Summary of the Invention

[0006] In view of this, the present invention provides a high-temperature vulcanized silicone rubber and a method for preparing the same. By treating raw methyl vinyl silicone rubber and using a crosslinking agent, a high-temperature vulcanized silicone rubber with good heat resistance and high modulus is obtained through a simple formulation and a convenient preparation method.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention provides a high-temperature vulcanized silicone rubber comprising the following raw materials in parts by weight: 100 parts of methyl vinyl silicone rubber raw rubber, 0.01-0.05 parts of treatment agent, 0.003-0.007 parts of catalyst, 0.8-2 parts of vulcanizing agent, 0.1-0.5 parts of crosslinking agent, and 45-55 parts of reinforcing filler.

[0009] Preferably, the structural formula of the treatment agent is:

[0010]

[0011] Among them, R1, R2, R3 and R4 are independently monovalent aliphatic or aromatic groups.

[0012] Preferably, the treatment agent is one or more of dimethyldiethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, diphenyldimethoxysilane, divinylmethyldiethoxysilane, methylvinyldimethoxysilane, and 3-piperazinylpropylmethyldimethoxysilane.

[0013] Preferably, the catalyst is one or more of dibutyltin dilaurate, dioctyltin dilaurate, stannous octanoate, dibutyltin diacetate, and stannous isooctanoate.

[0014] Preferably, the crosslinking agent is tetramethyltetravinylcyclotetrasiloxane and / or trimethyltrivinylcyclotrisiloxane.

[0015] Preferably, the reinforcing filler is silica.

[0016] The present invention also provides a method for preparing the high-temperature vulcanized silicone rubber, comprising the following steps:

[0017] (1) Mix raw methyl vinyl silicone rubber, treatment agent and catalyst and let stand to obtain treated raw rubber;

[0018] (2) After mixing the treated raw rubber, reinforcing filler, vulcanizing agent and crosslinking agent, the mixture is shaped to obtain a compound containing vulcanizing agent;

[0019] (3) The compound containing the vulcanizing agent is subjected to first-stage vulcanization and second-stage vulcanization in sequence to obtain high-temperature vulcanized silicone rubber.

[0020] Preferably, the mixing time in step (1) is 20 to 40 minutes, and the settling time is 6 to 72 hours.

[0021] Preferably, the shaping in step (2) involves thinning and rolling the sheet, with the thinning process being repeated 5 to 8 times.

[0022] Preferably, the pressure of the first stage of vulcanization in step (3) is 8-12 MPa, the temperature of the first stage of vulcanization is 160-180°C, and the time of the first stage of vulcanization is 25-40 min; the temperature of the second stage of vulcanization is 170-190°C, and the time of the second stage of vulcanization is 1.5-2.5 h.

[0023] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] In this invention, the hydroxyl groups at the ends of the silicone rubber molecules are first removed under the action of a treatment agent and a catalyst, thereby reducing the uncoupling degradation of the molecular backbone and improving the heat resistance of the silicone rubber. A catalyst is used to accelerate the reaction rate between the raw rubber and the treatment agent. A crosslinking agent with a specific structure is used to increase the modulus of the vulcanized silicone rubber. Reinforcing fillers are used to improve the mechanical properties of the vulcanized silicone rubber. The high-temperature vulcanized silicone rubber formulation of this invention is simple, has a high modulus, and exhibits good heat resistance. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0026] Figure 1 The images show a comparison of methyl vinyl silicone rubber before and after the reaction with the treatment agent. In example a, the infrared image of the methyl vinyl silicone rubber raw material in Example 1 before the reaction with the treatment agent is shown, and in example b, the infrared image of the methyl vinyl silicone rubber raw material in Example 1 after the reaction with the treatment agent is completed is shown.

[0027] Figure 2 Thermogravimetric curves of raw methyl vinyl silicone rubber for Example 1 and Comparative Example 1. Detailed Implementation

[0028] The high-temperature vulcanized silicone rubber of the present invention comprises the following raw materials in parts by weight: 100 parts of methyl vinyl silicone rubber raw rubber, 0.01 to 0.05 parts of treatment agent, 0.003 to 0.007 parts of catalyst, 0.8 to 2 parts of vulcanizing agent, 0.1 to 0.5 parts of crosslinking agent, and 45 to 55 parts of reinforcing filler.

[0029] In this invention, the vinyl content of the methyl vinyl silicone rubber raw material is preferably 0.05-0.10%.

[0030] The high-temperature vulcanized silicone rubber of the present invention contains 0.01 to 0.05 parts of a treatment agent, preferably 0.02 to 0.045 parts, more preferably 0.03 to 0.04 parts.

[0031] In this invention, the preferred structural formula of the treatment agent is:

[0032]

[0033] Among them, R1, R2, R3 and R4 are independently monovalent aliphatic or aromatic groups;

[0034] Further preferably, it is one or more of dimethyldiethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, diphenyldimethoxysilane, divinylmethyldiethoxysilane, methylvinyldimethoxysilane, and 3-piperazinylpropylmethyldimethoxysilane.

[0035] The high-temperature vulcanized silicone rubber of the present invention contains 0.003 to 0.007 parts of catalyst, preferably 0.004 to 0.006 parts, more preferably 0.0045 to 0.005 parts.

[0036] In this invention, the catalyst is preferably one or more of dibutyltin dilaurate, dioctyltin dilaurate, stannous octanoate, dibutyltin diacetate, and stannous isooctanoate.

[0037] The high-temperature vulcanized silicone rubber of the present invention contains 0.8 to 2 parts of vulcanizing agent, preferably 0.9 to 1.8 parts, more preferably 1 to 1.5 parts.

[0038] In this invention, the vulcanizing agent is preferably one or more of di-tert-butyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and dicumyl peroxide.

[0039] The high-temperature vulcanized silicone rubber of the present invention contains 0.1 to 0.5 parts of crosslinking agent, preferably 0.12 to 0.45 parts, more preferably 0.2 to 0.3 parts.

[0040] In this invention, the crosslinking agent is preferably tetramethyltetravinylcyclotetrasiloxane and / or trimethyltrivinylcyclotrisiloxane.

[0041] The high-temperature vulcanized silicone rubber of the present invention contains 45 to 55 parts of reinforcing filler, preferably 47 to 53 parts, and more preferably 49 to 51 parts.

[0042] In this invention, the reinforcing filler is preferably silica.

[0043] The present invention also provides a method for preparing the high-temperature vulcanized silicone rubber, comprising the following steps:

[0044] (1) Mix raw methyl vinyl silicone rubber, treatment agent and catalyst and let stand to obtain treated raw rubber;

[0045] (2) After mixing the treated raw rubber, reinforcing filler, vulcanizing agent and crosslinking agent, the mixture is shaped to obtain a compound containing vulcanizing agent;

[0046] (3) The compound containing the vulcanizing agent is subjected to first-stage vulcanization and second-stage vulcanization in sequence to obtain high-temperature vulcanized silicone rubber.

[0047] In this invention, the mixing time in step (1) is preferably 20-40 min, more preferably 25-35 min, and even more preferably 28-32 min; the settling time is preferably 6-72 h, more preferably 18-48 h, and even more preferably 24-36 h.

[0048] In this invention, the shaping in step (2) is preferably thinning and then rolling the sheet, and the thinning is preferably done 5 to 8 times, and more preferably 6 to 7 times.

[0049] In this invention, the pressure of the first-stage vulcanization in step (3) is preferably 8-12 MPa, more preferably 8.5-11 MPa, and even more preferably 9-10 MPa; the temperature of the first-stage vulcanization is preferably 160-180℃, more preferably 165-175℃, and even more preferably 168-170℃; the time of the first-stage vulcanization is preferably 25-40 min, more preferably 28-36 min, and even more preferably 30-32 min; the temperature of the second-stage vulcanization is preferably 170-190℃, more preferably 175-185℃, and even more preferably 180-183℃; the time of the second-stage vulcanization is preferably 1.5-2.5 h, more preferably 1.8-2.3 h, and even more preferably 2-2.2 h.

[0050] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0051] Example 1

[0052] 100 parts (by weight, the same below) of methyl vinyl silicone rubber raw rubber (ethylene content of 0.08%), 0.03 parts of methyl vinyl diethoxysilane and 0.005 parts of dibutyltin dilaurate were mixed in an internal mixer for 30 minutes and then allowed to stand for 48 hours to obtain the treated raw rubber.

[0053] After the treated raw rubber and 55 parts of fumed silica are mixed evenly in a mixer, a compound is obtained. 1 part of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and 0.1 part of trimethyltrivinylcyclotrisiloxane are added to the compound and mixed evenly in a two-roll mill. The mixture is passed through a thin mill 6 times, rolled into sheets, and a compound containing a vulcanizing agent is obtained.

[0054] The compound containing the vulcanizing agent is vulcanized in one stage on a flat vulcanizing machine at a pressure of 10 MPa, a temperature of 170°C, and a time of 30 min. Then, a second stage of vulcanization is carried out in a forced-air drying oven at a temperature of 180°C for 2 h to obtain high-temperature vulcanized silicone rubber.

[0055] Example 2

[0056] 100 parts (by weight, the same below) of methyl vinyl silicone rubber raw rubber (ethylene content of 0.07%), 0.035 parts of dimethyldiethoxysilane and 0.006 parts of stannous isooctanoate were mixed in an internal mixer for 35 minutes and then allowed to stand for 42 hours to obtain the treated raw rubber.

[0057] After the treated raw rubber and 53 parts of fumed silica were mixed evenly in a mixer, a compound was obtained. 1 part of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and 0.2 parts of tetramethyltetravinylcyclotetrasiloxane were added to the compound and mixed evenly in a two-roll mill. The mixture was passed through a thin mill 7 times, rolled into sheets, and a compound containing a vulcanizing agent was obtained.

[0058] The compound containing the vulcanizing agent is vulcanized in one stage on a flat vulcanizing machine at a pressure of 11 MPa, a temperature of 175°C, and a time of 32 min. Then, a second stage of vulcanization is carried out in a forced-air drying oven at a temperature of 183°C for 1.5 h to obtain high-temperature vulcanized silicone rubber.

[0059] Example 3

[0060] 100 parts (by weight, the same below) of methyl vinyl silicone rubber raw rubber (ethylene content of 0.08%), 0.05 parts of dimethyl dimethoxysilane and 0.007 parts of stannous isooctanoate were mixed in an internal mixer for 33 minutes and then allowed to stand for 40 hours to obtain the treated raw rubber.

[0061] After the treated raw rubber and 50 parts of fumed silica are mixed evenly in a mixer, a compound is obtained. 1 part of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and 0.3 parts of tetramethyltetravinylcyclotetrasiloxane are added to the compound and mixed evenly in a two-roll mill. The mixture is passed through a thin mill 6 times, rolled into sheets, and a compound containing a vulcanizing agent is obtained.

[0062] The compound containing the vulcanizing agent is vulcanized in one stage on a flat vulcanizing machine at a pressure of 9 MPa, a temperature of 168°C, and a time of 38 min. Then, a second stage of vulcanization is carried out in a forced-air drying oven at a temperature of 178°C for 1.5 h to obtain high-temperature vulcanized silicone rubber.

[0063] Example 4

[0064] 100 parts (by weight, the same below) of methyl vinyl silicone rubber raw rubber (ethylene content of 0.06%), 0.03 parts of diphenyldiethoxysilane and 0.005 parts of dibutyltin dilaurate were mixed in an internal mixer for 28 minutes and then allowed to stand for 56 hours to obtain the treated raw rubber.

[0065] After the treated raw rubber and 55 parts of fumed silica are mixed evenly in an internal mixer, a compound is obtained. 1 part of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and 0.4 parts of tetramethyltetravinylcyclotetrasiloxane are added to the compound and mixed evenly in an open mill. The mixture is passed through a thin mill 6 times, rolled into sheets, and a compound containing a vulcanizing agent is obtained.

[0066] The compound containing the vulcanizing agent is vulcanized in one stage on a flat vulcanizing machine at a pressure of 10 MPa, a temperature of 170°C, and a time of 30 min. Then, a second stage of vulcanization is carried out in a forced-air drying oven at a temperature of 180°C for 2 h to obtain high-temperature vulcanized silicone rubber.

[0067] Example 5

[0068] 100 parts (by weight, the same below) of methyl vinyl silicone rubber raw rubber (ethylene content of 0.08%), 0.05 parts of diphenyldiethoxysilane and 0.005 parts of dibutyltin dilaurate were mixed in an internal mixer for 30 minutes and then allowed to stand for 72 hours to obtain the treated raw rubber.

[0069] After the treated raw rubber and 48 parts of fumed silica were mixed evenly in a mixer, a compound was obtained. 1 part of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and 0.5 parts of trimethyltrivinylcyclotrisiloxane were added to the compound and mixed evenly in a two-roll mill. The mixture was passed through a thin mill 6 times, rolled into sheets, and a compound containing a vulcanizing agent was obtained.

[0070] The compound containing the vulcanizing agent is vulcanized in one stage on a flat vulcanizing machine at a pressure of 10 MPa, a temperature of 170°C, and a time of 30 min. Then, a second stage of vulcanization is carried out in a forced-air drying oven at a temperature of 180°C for 2 h to obtain high-temperature vulcanized silicone rubber.

[0071] Comparative Example 1

[0072] 100 parts (by weight, the same below) of methyl vinyl silicone rubber (ethylene content of 0.08%) and 55 parts of silica were mixed evenly in an internal mixer to obtain a compound. 1 part of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane was mixed evenly with the compound in a two-roll mill, passed through a thin mill 6 times, and then rolled into sheets to obtain a compound containing a vulcanizing agent.

[0073] The obtained compound rubber was subjected to a first-stage vulcanization on a flat vulcanizing machine at a pressure of 10 MPa, a temperature of 170°C, and a time of 30 min. A second-stage vulcanization was then carried out in a forced-air drying oven at a temperature of 180°C for 2 h.

[0074] Comparative Example 2

[0075] 100 parts (by weight, the same below) of methyl vinyl silicone rubber (ethylene content of 0.08%), 0.03 parts of dimethyldiethoxysilane, and 0.005 parts of dibutyltin dilaurate were mixed in an internal mixer for 30 minutes and then allowed to stand for 48 hours to obtain the treated raw rubber.

[0076] The treated raw rubber and 55 parts of silica were mixed evenly in a mixer to obtain a compound. 1 part of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and the compound were mixed evenly in a two-roll mill, passed through a thin mill 6 times, and rolled into sheets to obtain a compound with a vulcanizing agent.

[0077] The compound containing the vulcanizing agent is vulcanized in one stage on a flat vulcanizing machine at a pressure of 10 MPa, a temperature of 170°C, and a time of 30 min. Then, a second stage of vulcanization is carried out in a forced-air drying oven at a temperature of 180°C for 2 h to obtain high-temperature vulcanized silicone rubber.

[0078] The performance of the high-temperature vulcanized silicone rubbers of Examples 1-5 and Comparative Examples 1-2 was tested.

[0079] Infrared test:

[0080] Example 1 was analyzed using a TENSOR 27 infrared spectrometer (Bruker, Germany). Potassium bromide was ground and pressed into tablets with both methyl vinyl silicone rubber raw material and the high-temperature silicone rubber prepared in Example 1, and then tested. Wavenumbers ranged from 400 to 4000 cm⁻¹. -1 The resolution is 4cm. -1 .

[0081] Heat resistance test:

[0082] The thermal stability of the high-temperature vulcanized silicone rubbers of Examples 1, 4, and Comparative Examples 1-2 was tested using a simultaneous thermal analyzer. The test was conducted in air atmosphere at a heating rate of 10°C / min, with test temperatures ranging from 50 to 800°C. The heat resistance test results are shown in Table 1 and... Figure 2 As shown.

[0083] Table 1. Thermogravimetric data of high-temperature vulcanized silicone rubber in Examples 1, 4, and Comparative Examples 1-2.

[0084]

[0085] As can be seen from Comparative Example 1 and Example 1, no treatment agent or catalyst was added in Comparative Example 1, as shown in Table 1 and... Figure 2 The TGA data for Comparative Example 1 and Example 1 show that the initial decomposition temperatures are 336°C and 364°C, respectively; the 5% thermogravimetric temperatures are 366°C and 404°C, respectively; the 10% thermogravimetric temperatures are 392°C and 413°C, respectively; and the 50% thermogravimetric temperatures are 424°C and 489°C, respectively. The initial decomposition temperature, and the 5%, 10%, and 50% thermogravimetric temperatures increased by 24°C, 38°C, 21°C, and 65°C, respectively. Therefore, the heat resistance of the methyl vinyl silicone rubber with the addition of the treatment agent and catalyst is significantly improved because the -OH groups in the methyl vinyl silicone rubber are eliminated, reducing the unbuttoning degradation caused by the presence of -OH groups. Comparative Example 2, which did not contain a crosslinking agent compared to Example 4, showed the following results in Table 1: the initial decomposition temperatures of Comparative Example 2 and Example 4 were 360°C and 359°C, respectively; the 5% thermal weight loss temperatures were 396°C and 402°C, respectively; the 10% thermal weight loss temperatures were 409°C and 410°C, respectively; and the 50% thermal weight loss temperatures were 484°C and 488°C, respectively. The TGA data for Example 4 and Comparative Example 2 showed no significant change, indicating that the addition of the crosslinking agent did not affect the heat resistance of the raw rubber. Therefore, the addition of the treatment agent improved the heat resistance of the methyl vinyl silicone rubber raw rubber, while the crosslinking agent itself had no effect on the heat resistance of the methyl vinyl silicone rubber raw rubber.

[0086] Mechanical property testing:

[0087] (1) Tensile strength and elongation at break: The tensile strength and elongation at break of the specimens of Examples 1 to 5 and Comparative Examples 1 to 2 were tested with reference to the national standard GB / T528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber". The specimens were 100 mm long, 5 mm wide and 2 mm thick. Each example or comparative example was tested 3 times and the average value was taken.

[0088] (2) Tear strength: The tear strength of the specimens of Examples 1 to 5 and Comparative Examples 1 to 2 was tested with uncut right-angled strips in the national standard GB / T529-2008 "Determination of tear strength of vulcanized rubber or thermoplastic rubber (trouser-shaped, right-angled and crescent-shaped specimens)". Before cutting the specimens, each example or comparative example was tested 3 times and the average value was taken.

[0089] (3) Hardness: Refer to the national standard GB / T531.1-2008 "Test method for indentation hardness of vulcanized rubber or thermoplastic rubber - Part 1: Shore hardness test (Shore hardness)" to test the hardness of the samples of Examples 1 to 5 and Comparative Examples 1 to 2 with a Shore A hardness tester. The sample thickness is 7 mm. Each example or comparative example is tested 3 times and the average value is taken.

[0090] The mechanical property test results of the high-temperature vulcanized silicone rubbers of Examples 1-5 and Comparative Examples 1-2 are shown in Table 2.

[0091] Table 2. Mechanical property test data of high-temperature vulcanized silicone rubber in Examples 1-5 and Comparative Examples 1-2.

[0092]

[0093]

[0094] The mechanical property test data of the high-temperature vulcanized silicone rubbers in Examples 1-5 and Comparative Examples 1-2 show that, compared with Comparative Example 2, no treatment agent or catalyst was added. As shown in Table 2, the treatment agent increased the tensile strength of the vulcanized rubber by about 0.81 MPa; increased the elongation at break by about 70%; increased the tear strength by 0.96 KN / m; the hardness remained almost unchanged; and the 100%, 200%, and 300% moduli remained almost unchanged. Compared to Examples 1-5, Comparative Example 2 did not include a crosslinking agent. In Examples 1-5, based on 100 parts of raw rubber, the crosslinking agent amounts were 0.1, 0.2, 0.3, 0.4, and 0.5, respectively. The tensile strength did not change significantly with 0.1-0.3 parts of crosslinking agent; it began to decrease at 0.4 parts; and dropped to 9.62 MPa with 0.5 parts of crosslinking agent. The elongation at break gradually decreased with increasing crosslinking agent content, eventually leveling off. The tear strength of the vulcanizate initially increased and then decreased with increasing crosslinking agent content. The addition of the crosslinking agent increased the hardness of the vulcanizate. The 100% modulus significantly increased with the addition of the crosslinking agent, then slightly decreased with further increases in crosslinking agent dosage. The 200% and 300% moduli increased with the amount of crosslinking agent; however, after exceeding 0.1 parts, the crosslinking agent dosage had little effect on the modulus. Therefore, the combination of the eliminator and the crosslinking agent improved the tensile strength, tear strength, hardness, and modulus of the silicone rubber.

[0095] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-temperature vulcanized silicone rubber, characterized in that, The preparation raw materials contain the following parts by weight: 100 parts of methyl vinyl silicone rubber raw rubber, 0.01~0.05 parts of treatment agent, 0.003~0.007 parts of catalyst, 0.8~2 parts of vulcanizing agent, 0.1~0.3 parts of crosslinking agent, and 45~55 parts of reinforcing filler; The treatment agent is one or more of dimethyldiethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, diphenyldimethoxysilane, divinylmethyldiethoxysilane, methylvinyldimethoxysilane, and 3-piperazinylpropylmethyldimethoxysilane; The catalyst is one or more of dibutyltin dilaurate, dioctyltin dilaurate, stannous octanoate, dibutyltin diacetate, and stannous isooctanoate; The vulcanizing agent is one or more of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and dicumyl peroxide; The crosslinking agent is tetramethyltetravinylcyclotetrasiloxane and / or trimethyltrivinylcyclotrisiloxane.

2. The high-temperature vulcanized silicone rubber according to claim 1, characterized in that, The reinforcing filler is silica.

3. The method for preparing a high-temperature vulcanized silicone rubber according to claim 1 or 2, characterized in that, Includes the following steps: (1) Mix raw methyl vinyl silicone rubber, treatment agent and catalyst and let stand to obtain treated raw rubber; (2) After mixing the treated raw rubber, reinforcing filler, vulcanizing agent and crosslinking agent, the mixture is shaped to obtain a compound containing vulcanizing agent; (3) The compound containing the vulcanizing agent is subjected to first-stage vulcanization and second-stage vulcanization in sequence to obtain high-temperature vulcanized silicone rubber; In step (3), the pressure of the first stage of vulcanization is 8~12MPa, the temperature of the first stage of vulcanization is 160~180℃, and the time of the first stage of vulcanization is 25~40min; the temperature of the second stage of vulcanization is 170~190℃, and the time of the second stage of vulcanization is 1.5~2.5h.

4. The method for preparing high-temperature vulcanized silicone rubber according to claim 3, characterized in that, The mixing time in step (1) is 20-40 min, and the settling time is 6-72 h.

5. The method for preparing high-temperature vulcanized silicone rubber according to claim 3 or 4, characterized in that, The shaping process described in step (2) involves thinning and rolling the sheet into a roll, with the thinning process being repeated 5 to 8 times.

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