A polyborosiloxane damping additive for phenyl silicone rubber and its preparation method and application

Abstract

The present invention belongs to the technical field of organosilicon damping materials, and specifically relates to a polyborosiloxane damping additive for phenyl silicone rubber, a preparation method thereof, and an application thereof. The polyborosiloxane damping additive for phenyl silicone rubber is prepared from raw materials including hydroxyl-terminated polysiloxane and a boron-containing aromatic compound, wherein the hydroxyl ratio of the hydroxyl-terminated polysiloxane to the boron-containing aromatic compound is 1:(0.2-3). From the perspective of molecular structure design, the present invention introduces aromatic groups into polyborosiloxane molecules. The resulting polyborosiloxane damping additive has good compatibility with phenyl silicone rubber, does not phase separate from phenyl silicone rubber, and can provide phenyl silicone rubber with good damping performance, greatly broadening the effective damping temperature range of phenyl silicone rubber, and meeting the market demand for high-performance damping silicone rubber.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic silicon damping materials, and in particular relates to a polyborosiloxane damping additive for phenyl silicone rubber, a preparation method thereof, and an application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] With the continuous advancement of technology, the operating speed of mechanical equipment is increasing, resulting in more intense vibration during operation. This vibration not only significantly reduces the accuracy, reliability, and stability of the equipment, but also shortens its service life. Therefore, controlling and eliminating vibration has become a key criterion for measuring the level of equipment manufacturing. Rubber damping materials, due to their excellent vibration-reducing properties, can effectively reduce the vibration of mechanical equipment during operation, making the development of high-performance rubber damping materials a key research topic in materials science.

[0004] Silicone rubber, due to its unique -Si-O-Si- backbone structure, exhibits significant performance differences from traditional carbon-chain rubbers. The bond energy of the Si-O-Si bond is as high as 460 kJ / mol, far exceeding the 346 kJ / mol of the C-C bond. Furthermore, the bond length and angle of the Si-O-Si bond are relatively large. These structural characteristics endow silicone rubber with excellent resistance to high and low temperatures, radiation, and UV rays. However, due to the high flexibility of the silicone rubber molecular chain, its damping performance is relatively poor. To improve the damping performance of silicone rubber, researchers have introduced sterically hindered phenyl groups into silicone rubber. However, even so, the damping performance of phenyl silicone rubber still fails to meet the requirements of applications with high damping requirements. Therefore, to further enhance the damping performance of phenyl silicone rubber, it is still necessary to modify it by adding damping additives.

[0005] Polyborosiloxane is an organosilicon polymer with boron incorporated into the polysiloxane molecule. This organic-inorganic hybrid material possesses high bond energies, namely, BO bonds (537.6 kJ / mol) and Si-O bonds (422.5 kJ / mol), which impart excellent heat and oxidation resistance, leading to its widespread use in flame retardants, self-healing materials, and impact-resistant materials. Existing patents, such as CN117467278A and CN109943076A, create silicone rubber composites by adding polyborosiloxane to room-temperature vulcanized silicone rubber. However, due to the RTV silicone rubber matrix, the tensile strength is less than 1 MPa, resulting in poor mechanical properties. Furthermore, due to the poor compatibility between polyborosiloxane and silicone rubber, phase separation easily occurs, resulting in insufficient damping performance for the silicone rubber composite. Summary of the Invention

[0006] To address the existing issues of poor compatibility and prone to phase separation between polyborosiloxane and phenyl silicone rubber, the present invention provides a polyborosiloxane-based damping additive for phenyl silicone rubber, as well as its preparation method and application. By incorporating aromatic groups into the polyborosiloxane molecule through molecular structure design, the resulting polyborosiloxane-based damping additive exhibits excellent compatibility with phenyl silicone rubber, resists phase separation, and provides excellent damping performance for the latter, significantly broadening its effective damping temperature range and meeting market demand for high-performance damping silicone rubber.

[0007] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0008] In a first aspect, the present invention provides a polyborosiloxane damping additive for phenyl silicone rubber, wherein the polyborosiloxane damping additive has a number average molecular weight of 1000 to 12000 and has a structure as shown in Formula I, Formula II, Formula III or Formula IV:

[0009] Formula I;

[0010] Formula II;

[0011] Formula III;

[0012] Formula IV;

[0013] Wherein, R3 is selected from one of phenyl, biphenyl and anthracene, a is selected from a positive integer between 1 and 5, b:a≤50%, and the structural formula of A is shown in V:

[0014] Formula V;

[0015] In the formula, R1 and R2 are independently selected from one or a combination of methyl, phenyl, vinyl and hydrogen atoms, m:n≤30%, m≤100.

[0016] Due to the introduction of boron atoms, p-π and d-π conjugation is formed in polyborosiloxane, and the dissociation and reassociation of the dynamic boron-oxygen bond can effectively consume energy, which shows great potential in damping additives. However, polyborosiloxane has poor compatibility with silicone rubber and is prone to phase separation. The present invention uses a boron-containing aromatic compound containing an aromatic ring as the raw material for forming a polyborosiloxane-type damping additive. The aromatic group is introduced into the polyborosiloxane through cross-linking of boric acid with the hydroxyl group in the polysiloxane. The resulting polyborosiloxane-type damping additive has good compatibility with phenyl silicone rubber, does not phase separate from phenyl silicone rubber, and can provide phenyl silicone rubber with good damping performance.

[0017] Preferably, the viscosity of the polyborosiloxane damping additive is 100-20000 mPa·s.

[0018] Preferably, the number average molecular weight of A is 1,000 to 10,000.

[0019] Preferably, R1 and R2 are both methyl.

[0020] Preferably, a is 1 or 2, and b is 1.

[0021] As the degree of polymerization of polyborosiloxane increases, the proportion of boron and aromatic groups decreases, resulting in a decrease in the performance of polyborosiloxane-based damping additives. To increase the boron content, the reaction temperature and time are controlled to avoid the formation of high molecular weight polyborosiloxane.

[0022] In a second aspect, the present invention provides a method for preparing the polyborosiloxane damping additive as described in the first aspect, comprising the following steps:

[0023] The terminal hydroxyl polysiloxane is mixed with an organic solvent, and then a boron-containing aromatic compound is added. After uniform mixing, the mixture is heated for reaction to obtain a crude polyborosiloxane product. The crude polyborosiloxane product is subjected to rotary evaporation, dissolution, filtration, rotary evaporation and drying to obtain the polyborosiloxane damping additive.

[0024] Preferably, the hydroxyl ratio of the hydroxyl-terminated polysiloxane to the boron-containing aromatic compound is 1:(0.2-3).

[0025] Preferably, the number average molecular weight of the hydroxyl-terminated polysiloxane is 1000-10000, and the structural formula of the hydroxyl-terminated polysiloxane is as shown in Formula VI:

[0026] Formula VI.

[0027] Preferably, the boron-containing aromatic compound includes at least one of phenylboronic acid, 1,4-phenyldiboronic acid, 1,3-phenyldiboronic acid, biphenyldiboronic acid and anthracene-9,10 diboronic acid.

[0028] Preferably, the reaction temperature of the heating reaction is 90° C. to 150° C., and the reaction time is 8 to 24 h.

[0029] Preferably, the organic solvent includes at least one of toluene and xylene.

[0030] In a third aspect, the present invention provides use of the polyborosiloxane damping additive as described in the first aspect in the preparation of silicone rubber.

[0031] The beneficial effects achieved by one or more technical solutions of the present invention are as follows:

[0032] (1) The polyborosiloxane-based damping additive for phenyl silicone rubber prepared in the present invention has good compatibility with phenyl silicone rubber compared to other polyborosiloxanes and does not cause phase separation. The introduction of polyborosiloxane into phenyl silicone rubber can form a boron-oxygen dynamic bond between the phenyl silicone rubber and the polyborosiloxane. In addition, the polyborosiloxane in the present invention contains aromatic groups, which can generate π-π interactions with the phenyl silicone rubber, significantly increasing the energy dissipation of the phenyl silicone rubber and improving the damping performance of the phenyl silicone rubber.

[0033] (2) The polyborosiloxane damping additive for phenyl silicone rubber prepared by the present invention has good compatibility with phenyl silicone rubber, and the high-temperature damping performance of the damping silicone rubber prepared is significantly improved. The effective damping temperature range is increased by at least 14°C, and the temperature range of tanδ>0.2 is increased by at least 179°C, without affecting the glass transition temperature of the silicone rubber. It has excellent mechanical properties, with a maximum tensile strength of 5.7MPa, good fatigue resistance, and a long service life, which broadens the application range of damping silicone rubber. In addition, the preparation process of the damping additive is simple, the preparation cost is low, and it is easy to apply in the market.

[0034] (3) Currently, the research on polyborosiloxane is mainly applied in the fields of impact-resistant materials, self-healing materials, adhesive materials, etc. The present invention utilizes the energy dissipation during the dissociation and association of the dynamic boron-oxygen bonds in polyborosiloxane to develop its application as a damping additive, and introduces phenyl groups to increase its compatibility with phenyl silicone rubber. A polyborosiloxane-type damping additive for phenyl silicone rubber is prepared, which solves the problem of poor compatibility between polyborosiloxane and phenyl silicone rubber and broadens the application range of polyborosiloxane. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0036] Figure 1 is the dynamic mechanical (DMA) curve of the damping silicone rubber in Examples 1 to 3;

[0037] Figure 2 It is the dynamic mechanical curve of the damping silicone rubber in comparative examples 1 to 4. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples.

[0039] Example 1

[0040] 50 g of hydroxy-terminated dimethyl polysiloxane (0.01 mol, containing 0.02 mol of hydroxyl groups) with a number-average molecular weight of 5000 was mixed with 100 mL of toluene in a 250 mL three-necked flask equipped with a condenser reflux system. The flask was placed in an oil bath with magnetic stirring. 3.66 g (0.03 mol) of phenylboric acid was slowly added while stirring at room temperature. The mixture was stirred at room temperature for 30 min, then heated to 120°C and stirred at 120°C for 10 h to obtain a crude product containing toluene as solvent. The crude product containing toluene was cooled to room temperature, filtered to remove unreacted phenylboric acid, and then the toluene solvent was removed by rotary evaporation. The product was then dried in a vacuum oven at 70°C for 24 h to obtain a polyborosiloxane damping additive. The polyborosiloxane damping additive had a number-average molecular weight of 5719 and a viscosity of 2250 mPa·s.

[0041] The raw materials were weighed in the following ratios: 100 parts by weight of phenyl silicone rubber (monophenyl silicone rubber with a 30% molar phenyl content), 50 parts by weight of TS530 silica, 30 parts by weight of a polyborosiloxane damping additive, and 2 parts by weight of a bis(2,4)-dimethylbenzene vulcanizing agent. The phenyl silicone rubber was first placed in a kneader, and TS530 silica was added in several portions. After mixing at 50°C, the rubber was removed and allowed to stand at room temperature for 16 hours. Then, 2 phr of the bis(2,4)-dimethylbenzene vulcanizing agent and the polyborosiloxane damping additive were added on an open mill and mixed at 30°C. The rubber was then vulcanized in a vacuum vulcanizer at a temperature of 100°C, a time of 10 minutes, and a pressure of 10 MPa. Finally, a second vulcanization was performed in a forced air oven at 180°C for 4 hours to obtain the 2 mm thick damping silicone rubber required for testing.

[0042] Example 2

[0043] 50 g of hydroxy-terminated dimethyl polysiloxane (0.05 mol, containing 0.1 mol of hydroxyl groups) with a number-average molecular weight of 1000 was mixed with 100 mL of toluene in a 250 mL three-necked flask equipped with a condenser reflux system. The flask was placed in an oil bath with magnetic stirring. 1.22 g (0.01 mol) of phenylboric acid was slowly added while stirring at room temperature. The mixture was stirred at room temperature for 30 min, then heated to 120°C and stirred at 120°C for 10 h to obtain a crude product containing toluene as solvent. The crude product containing toluene was cooled to room temperature, filtered to remove unreacted phenylboric acid, and then the toluene solvent was removed by rotary evaporation. The product was then dried in a vacuum oven at 70°C for 24 h to obtain a polyborosiloxane damping additive. The polyborosiloxane damping additive had a number-average molecular weight of 1154 and a viscosity of 130 mPa·s.

[0044] The polyborosiloxane damping additive obtained in this example was used to prepare a 2 mm thick damping silicone rubber required for the test. The raw material ratio and reaction conditions were the same as in Example 1 except that the polyborosiloxane damping additive was different.

[0045] Example 3

[0046] 50 g of hydroxy-terminated dimethyl polysiloxane (0.05 mol, containing 0.1 mol of hydroxyl groups) with a number-average molecular weight of 1000 was mixed with 100 mL of toluene in a 250 mL three-necked flask equipped with a condenser reflux system. The flask was placed in an oil bath with magnetic stirring. 8.3 g (0.05 mol) of 1,4-phenylenediboronic acid was slowly added while stirring at room temperature. The mixture was stirred at room temperature for 30 min, then heated to 120°C and stirred at 120°C for 10 h to obtain a crude product containing toluene as solvent. The crude product containing toluene was cooled to room temperature, filtered to remove unreacted 1,4-phenylenediboronic acid, and then the toluene solvent was removed by rotary evaporation. The product was then dried in a vacuum oven at 70°C for 24 h to obtain a polyborosiloxane damping additive. The polyborosiloxane damping additive had a number-average molecular weight of 5341 and a viscosity of 3420 mPa·s.

[0047] The polyborosiloxane damping additive obtained in this example was used to prepare a 2 mm thick damping silicone rubber required for the test. The raw material ratio and reaction conditions were the same as in Example 1 except that the polyborosiloxane damping additive was different.

[0048] Comparative Example 1

[0049] 50 g of hydroxy-terminated dimethyl polysiloxane (0.06 mol, containing 0.12 mol of hydroxyl groups) with a number-average molecular weight of 1000 was mixed with 100 mL of toluene in a 250 mL three-necked flask equipped with a condenser reflux system. The flask was placed in an oil bath with magnetic stirring. 3.1 g (0.05 mol) of boric acid was slowly added while stirring at room temperature. The mixture was stirred at room temperature for 30 min, then heated to 120°C and stirred at 120°C for 10 h to obtain a crude product containing toluene as solvent. The crude product containing toluene was cooled to room temperature, filtered to remove unreacted boric acid, and then the toluene solvent was removed by rotary evaporation. The product was then dried in a vacuum oven at 70°C for 24 h to obtain the polyborosiloxane. The polyborosiloxane was a gel-like solid with a number-average molecular weight of 1198.

[0050] The polyborosiloxane product obtained in this example was used to prepare 2 mm thick damping silicone rubber required for the test. The raw material ratio and reaction conditions were the same as in Example 1 except that the polyborosiloxane product was used instead of the polyborosiloxane damping additive.

[0051] Comparative Example 2

[0052] 50 g of hydroxy-terminated dimethyl polysiloxane (0.05 mol, containing 0.1 mol of hydroxyl groups) with a number-average molecular weight of 1000 was mixed with 100 mL of toluene in a 250 mL three-necked flask equipped with a condenser reflux system. The flask was placed in an oil bath with magnetic stirring. 0.61 g (0.005 mol) of phenylboric acid was slowly added while stirring at room temperature. The mixture was stirred at room temperature for 30 min, then heated to 120°C and stirred at 120°C for 10 h to obtain a crude product containing toluene as solvent. The crude product containing toluene was cooled to room temperature, filtered to remove unreacted phenylboric acid, and then the toluene solvent was removed by rotary evaporation. The product was then dried in a vacuum oven at 70°C for 24 h to obtain the polyborosiloxane. This polyborosiloxane had a number-average molecular weight of 1012 and a viscosity of 110 mPa·s.

[0053] The polyborosiloxane product obtained in this example was used to prepare 2 mm thick damping silicone rubber required for the test. The raw material ratio and reaction conditions were the same as in Example 1 except that the polyborosiloxane product was used instead of the polyborosiloxane damping additive.

[0054] Comparative Example 3

[0055] The raw materials were weighed in the ratio of 100 parts by weight of phenyl silicone rubber (monophenyl silicone rubber with a phenyl molar content of 30%), 50 parts by weight of TS530 silica, and 2 parts by weight of a curing agent, bis(2,4-bis(2,4-bis(2,4-bis(2,4-bis(2,4-bis(2,4-bis(2,4-bis(2,4-bis(2,4-bis(2,4-bis(2,4-bis(2,4-bis(2,4-bis(2,4-bis(2,4-bis(2,4-bis(2,4-bis(2,4-bis(2,4-bis(2,4-bis(2,4-bis(2,4-bis(2,4-bis(2,4-dioxo-1,300,0 ...

[0056] Comparative Example 4

[0057] The raw materials were weighed in the ratio of 100 parts by weight of methyl silicone rubber, 50 parts by weight of TS530 silica, 30 parts by weight of the polyborosiloxane damping additive of Example 1, and 2 parts by weight of a curing agent, bis(2,4-dimethylsiloxane). The raw phenyl silicone rubber was first placed in a kneader and TS530 silica was added in several portions. After mixing at 50°C, the rubber was removed and allowed to stand at room temperature for 16 hours. Then, 2 phr of a curing agent, bis(2,4-dimethylsiloxane), and the polyborosiloxane damping additive were added on an open mill and mixed at 30°C. The rubber was then vulcanized in a vacuum vulcanizer at a temperature of 100°C, a time of 10 minutes, and a pressure of 10 MPa. Finally, a second vulcanization was performed in a forced air oven at 180°C for 4 hours to obtain the 2 mm thick damping silicone rubber required for the test.

[0058] The mechanical properties and damping performance tests of the damping silicone rubbers obtained in Examples 1 to 3 and Comparative Examples 1 to 5 are shown in Table 1, Table 2, Figure 1 and Figure 2 shown.

[0059] Table 1 Mechanical properties of damping silicone rubber

[0060]

[0061] Table 2 Damping properties of damping silicone rubber

[0062]

[0063] Compared to the polyborosiloxane product prepared using boric acid as a raw material in Comparative Example 1, the polyborosiloxane damping additives prepared using boron-containing aromatic compounds containing phenyl groups in Examples 1-3 have a similar structure to phenyl silicone rubber, do not undergo significant phase separation, and exhibit excellent damping performance over a wide temperature range. Compared to Comparative Example 2, the boron content of the polyborosiloxane damping additives in Examples 1-3 is significantly higher, resulting in even better damping performance for the damping silicone rubber. In Comparative Example 4, the polyborosiloxane damping additive was added to methyl silicone rubber. Due to the inherent poor damping performance of methyl silicone rubber and significant phase separation, the damping capacity of the resulting damping silicone rubber was significantly reduced, demonstrating that the polyborosiloxane damping additive of the present invention is specifically formulated for phenyl silicone rubber. Compared to Comparative Example 3, which did not include the polyborosiloxane damping additive, the damping silicone rubber obtained in Examples exhibited significantly improved tan δ > 0.3 and tan δ > 0.2 temperature ranges and a loss factor at 150°C, and exhibited excellent mechanical properties. This is because polyborosiloxane can form boron-oxygen dynamic bonds with phenyl silicone rubber. The introduction of dynamic bonds will cause dissociation and association under the dynamic strain of the damping composite material, thereby increasing energy loss, significantly improving the damping performance of phenyl silicone rubber, and widening the effective damping temperature range. The phenyl-containing polyborosiloxane is more similar in structure to phenyl silicone rubber, will not phase separate, and has better mechanical properties.

[0064] Example 4

[0065] 50 g of hydroxy-terminated dimethyl polysiloxane (0.05 mol, containing 0.1 mol of hydroxyl groups) with a number-average molecular weight of 10,000 was mixed with 100 mL of toluene in a 250 mL three-necked flask equipped with a condenser reflux system. The flask was placed in an oil bath with magnetic stirring. 8.3 g (0.05 mol) of 1,4-phenylenediboronic acid was slowly added while stirring at room temperature. The mixture was stirred at room temperature for 30 min, then heated to 120°C and stirred at 120°C for 10 h to obtain a crude product containing toluene as solvent. The crude product containing toluene was cooled to room temperature, filtered to remove unreacted 1,4-phenylenediboronic acid, and then the toluene solvent was removed by rotary evaporation. The product was then dried in a vacuum oven at 70°C for 24 h to obtain a polyborosiloxane damping additive. The polyborosiloxane damping additive had a number-average molecular weight of 11,770 and a viscosity of 10,420 mPa·s.

[0066] The polyborosiloxane damping additive obtained in this example was used to prepare a 2 mm thick damping silicone rubber required for the test. The raw material ratio and reaction conditions were the same as in Example 1 except that the polyborosiloxane damping additive was different.

[0067] Example 5

[0068] 50 g of 1000-molecular-weight hydroxy-terminated dimethyl polysiloxane (0.05 mol, containing 0.1 mol of hydroxyl groups) and 100 mL of toluene were mixed in a 250 mL three-necked flask equipped with a condenser reflux system. The flask was placed in an oil bath with magnetic stirring. 8.3 g (0.05 mol) of 1,3-phenylenediboronic acid was slowly added while stirring at room temperature. The mixture was stirred at room temperature for 30 min, then heated to 120°C and stirred at 120°C for 10 h to obtain a crude product containing toluene as solvent. The crude product containing toluene was cooled to room temperature, filtered to remove unreacted 1,4-phenylenediboronic acid, and then the toluene solvent was removed by rotary evaporation. The product was then dried in a vacuum oven at 70°C for 24 h to obtain a polyborosiloxane damping additive. This polyborosiloxane damping additive has a number average molecular weight of 5412 and a viscosity of 3535 mPa·s.

[0069] The polyborosiloxane damping additive obtained in this example was used to prepare a 2 mm thick damping silicone rubber required for the test. The raw material ratio and reaction conditions were the same as in Example 1 except that the polyborosiloxane damping additive was different.

[0070] Example 6

[0071] 50 g of 1000-molecular-weight hydroxy-terminated dimethyl polysiloxane (0.05 mol, containing 0.1 mol of hydroxyl groups) and 100 mL of toluene were mixed in a 250 mL three-necked flask equipped with a condenser reflux system. The flask was placed in an oil bath with magnetic stirring. 12.1 g (0.05 mol) of biphenyldiboronic acid was slowly added while stirring at room temperature. The mixture was stirred at room temperature for 30 min, then heated to 120°C and stirred at 120°C for 10 h to obtain a crude product containing toluene as solvent. The crude product containing toluene was cooled to room temperature, filtered to remove unreacted 1,4-phenylenediboronic acid, and then the toluene solvent was removed by rotary evaporation. The product was then dried in a vacuum oven at 70°C for 24 h to obtain a polyborosiloxane damping additive. This polyborosiloxane damping additive has a number average molecular weight of 5341 and a viscosity of 3420 mPa·s.

[0072] The polyborosiloxane damping additive obtained in this example was used to prepare a 2 mm thick damping silicone rubber required for the test. The raw material ratio and reaction conditions were the same as in Example 1 except that the polyborosiloxane damping additive was different.

[0073] Example 7

[0074] 50 g of 1000-molecular-weight hydroxy-terminated dimethyl polysiloxane (0.05 mol, containing 0.1 mol of hydroxyl groups) and 100 mL of toluene were mixed in a 250 mL three-necked flask equipped with a condenser reflux system. The flask was placed in an oil bath with magnetic stirring. 13.3 g (0.05 mol) of anthracene-9,10-diboronic acid was slowly added while stirring at room temperature. The mixture was stirred at room temperature for 30 min, then heated to 120°C and stirred at 120°C for 10 h to obtain a crude product containing toluene as solvent. The crude product containing toluene was cooled to room temperature, filtered to remove unreacted 1,4-phenylenediboronic acid, and then rotary evaporated to remove the toluene solvent. The product was then dried in a vacuum oven at 70°C for 24 h to obtain a polyborosiloxane damping additive. This polyborosiloxane damping additive has a number average molecular weight of 5821 and a viscosity of 3780 mPa·s.

[0075] The polyborosiloxane damping additive obtained in this example was used to prepare a 2 mm thick damping silicone rubber required for the test. The raw material ratio and reaction conditions were the same as in Example 1 except that the polyborosiloxane damping additive was different.

[0076] Example 8

[0077] 50 g of hydroxyl-terminated polysiloxane (composed of dimethylsiloxane and methylphenylsiloxane segments with a number-average molecular weight of 1000, with a ratio of 30% dimethylsiloxane to methylphenylsiloxane) was mixed with 100 mL of toluene in a 250 mL three-necked flask equipped with a condenser reflux system. The flask was placed in an oil bath with magnetic stirring. 1.22 g (0.01 mol) of phenylboric acid was slowly added while stirring at room temperature. The mixture was stirred at room temperature for 30 minutes, then heated to 120°C and stirred at 120°C for 10 hours to obtain a crude product containing toluene as solvent. The crude product containing toluene was cooled to room temperature, filtered to remove unreacted phenylboric acid, and then the toluene solvent was removed by rotary evaporation. The product was then dried in a vacuum oven at 70°C for 24 hours to obtain a polyborosiloxane damping additive.

[0078] The polyborosiloxane damping additive obtained in this example was used to prepare a 2 mm thick damping silicone rubber required for the test. The raw material ratio and reaction conditions were the same as in Example 1 except that the polyborosiloxane damping additive was different.

[0079] Example 9

[0080] 50 g of hydroxyl-terminated polysiloxane (composed of dimethylsiloxane and methylvinylsiloxane segments with a number-average molecular weight of 1000, with a ratio of 25% dimethylsiloxane to methylvinylsiloxane) was mixed with 100 mL of toluene in a 250 mL three-necked flask equipped with a condenser reflux system. The flask was placed in an oil bath with magnetic stirring. 1.22 g (0.01 mol) of phenylboric acid was slowly added while stirring at room temperature. The mixture was stirred at room temperature for 30 minutes, then heated to 120°C and stirred at 120°C for 10 hours to obtain a crude product containing toluene solvent. The crude product containing toluene solvent was cooled to room temperature, filtered to remove unreacted phenylboric acid, and then the toluene solvent was removed by rotary evaporation. The product was then dried in a vacuum oven at 70°C for 24 hours to obtain a polyborosiloxane damping additive.

[0081] The polyborosiloxane damping additive obtained in this example was used to prepare a 2 mm thick damping silicone rubber required for the test. The raw material ratio and reaction conditions were the same as in Example 1 except that the polyborosiloxane damping additive was different.

[0082] Example 10

[0083] 50 g of hydroxyl-terminated polysiloxane (composed of dimethylsiloxane and methylsiloxane segments with a number-average molecular weight of 1000, with a dimethylsiloxane to methylsiloxane ratio of 20%) and 100 mL of toluene were mixed in a 250 mL three-necked flask equipped with a condenser reflux system. The flask was placed in an oil bath with magnetic stirring. 1.22 g (0.01 mol) of phenylboric acid was slowly added while stirring at room temperature. The mixture was stirred at room temperature for 30 minutes, then heated to 120°C and stirred at 120°C for 10 hours to obtain a crude product containing toluene solvent. The crude product containing toluene solvent was cooled to room temperature, filtered to remove unreacted phenylboric acid, and then the toluene solvent was removed by rotary evaporation. The product was then dried in a vacuum oven at 70°C for 24 hours to obtain a polyborosiloxane damping additive.

[0084] The polyborosiloxane damping additive obtained in this example was used to prepare a 2 mm thick damping silicone rubber required for the test. The raw material ratio and reaction conditions were the same as in Example 1 except that the polyborosiloxane damping additive was different.

[0085] Example 11

[0086] 50 g of hydroxyl-terminated polysiloxane (comprising dimethylsiloxane and divinylsiloxane segments with a number-average molecular weight of 1000, with a ratio of 30% dimethylsiloxane to divinylsiloxane) and 100 mL of toluene were mixed in a 250 mL three-necked flask equipped with a condenser reflux system. The flask was placed in an oil bath with magnetic stirring. 1.22 g (0.01 mol) of phenylboric acid was slowly added while stirring at room temperature. The mixture was stirred at room temperature for 30 minutes, then heated to 120°C and stirred at 120°C for 10 hours to obtain a crude product containing toluene as solvent. The crude product containing toluene was cooled to room temperature, filtered to remove unreacted phenylboric acid, and then the toluene solvent was removed by rotary evaporation. The product was then dried in a vacuum oven at 70°C for 24 hours to obtain a polyborosiloxane damping additive.

[0087] The polyborosiloxane damping additive obtained in this example was used to prepare a 2 mm thick damping silicone rubber required for the test. The raw material ratio and reaction conditions were the same as in Example 1 except that the polyborosiloxane damping additive was different.

[0088] Example 12

[0089] 50 g of hydroxyl-terminated polysiloxane (comprising dimethylsiloxane and vinylphenylsiloxane segments with a number-average molecular weight of 1000, with a ratio of 30% dimethylsiloxane to vinylphenylsiloxane) was mixed with 100 mL of toluene in a 250 mL three-necked flask equipped with a condenser reflux system. The flask was placed in an oil bath with magnetic stirring. 1.22 g (0.01 mol) of phenylboric acid was slowly added while stirring at room temperature. The mixture was stirred at room temperature for 30 minutes, then heated to 120°C and stirred at 120°C for 10 hours to obtain a crude product containing toluene as solvent. The crude product containing toluene was cooled to room temperature, filtered to remove unreacted phenylboric acid, and then the toluene solvent was removed by rotary evaporation. The product was then dried in a vacuum oven at 70°C for 24 hours to obtain a polyborosiloxane damping additive.

[0090] The polyborosiloxane damping additive obtained in this example was used to prepare a 2 mm thick damping silicone rubber required for the test. The raw material ratio and reaction conditions were the same as in Example 1 except that the polyborosiloxane damping additive was different.

[0091] Example 13

[0092] 50 g of hydroxyl-terminated polysiloxane (comprising dimethylsiloxane and vinylsiloxane segments with a number-average molecular weight of 1000, with a ratio of 30% dimethylsiloxane to vinylsiloxane) and 100 mL of toluene were mixed in a 250 mL three-necked flask equipped with a condenser reflux system. The flask was placed in an oil bath with magnetic stirring. 1.22 g (0.01 mol) of phenylboric acid was slowly added while stirring at room temperature. The mixture was stirred at room temperature for 30 minutes, then heated to 120°C and stirred at 120°C for 10 hours to obtain a crude product containing toluene as solvent. The crude product containing toluene was cooled to room temperature, filtered to remove unreacted phenylboric acid, and then the toluene solvent was removed by rotary evaporation. The product was then dried in a vacuum oven at 70°C for 24 hours to obtain a polyborosiloxane damping additive.

[0093] The polyborosiloxane damping additive obtained in this example was used to prepare a 2 mm thick damping silicone rubber required for the test. The raw material ratio and reaction conditions were the same as in Example 1 except that the polyborosiloxane damping additive was different.

[0094] Example 14

[0095] 50 g of hydroxyl-terminated polysiloxane (composed of dimethylsiloxane and diphenylsiloxane segments with a 30% ratio of dimethylsiloxane to diphenylsiloxane) with a number-average molecular weight of 1000 was mixed with 100 mL of toluene in a 250 mL three-necked flask equipped with a condenser reflux system. The flask was placed in an oil bath with magnetic stirring. 1.22 g (0.01 mol) of phenylboric acid was slowly added while stirring at room temperature. The mixture was stirred at room temperature for 30 minutes, then heated to 120°C and stirred at 120°C for 10 hours to obtain a crude product containing toluene solvent. The crude product containing toluene solvent was cooled to room temperature, filtered to remove unreacted phenylboric acid, and then the toluene solvent was removed by rotary evaporation. The product was then dried in a vacuum oven at 70°C for 24 hours to obtain a polyborosiloxane damping additive.

[0096] The polyborosiloxane damping additive obtained in this example was used to prepare a 2 mm thick damping silicone rubber required for the test. The raw material ratio and reaction conditions were the same as in Example 1 except that the polyborosiloxane damping additive was different.

[0097] Example 15

[0098] 50 g of hydroxyl-terminated polysiloxane (composed of dimethylsiloxane and phenylsiloxane segments with a number-average molecular weight of 1000, with a ratio of 30% dimethylsiloxane to phenylsiloxane) and 100 mL of toluene were mixed in a 250 mL three-necked flask equipped with a condenser reflux system. The flask was placed in an oil bath with magnetic stirring. 1.22 g (0.01 mol) of phenylboric acid was slowly added while stirring at room temperature. The mixture was stirred at room temperature for 30 minutes, then heated to 120°C and stirred at 120°C for 10 hours to obtain a crude product containing toluene solvent. The crude product containing toluene solvent was cooled to room temperature, filtered to remove unreacted phenylboric acid, and then the toluene solvent was removed by rotary evaporation. The product was then dried in a vacuum oven at 70°C for 24 hours to obtain a polyborosiloxane damping additive.

[0099] The polyborosiloxane damping additive obtained in this example was used to prepare a 2 mm thick damping silicone rubber required for the test. The raw material ratio and reaction conditions were the same as in Example 1 except that the polyborosiloxane damping additive was different.

[0100] Example 16

[0101] 50 g of hydroxyl-terminated polysiloxane (composed of dimethylsiloxane and siloxane segments with a number-average molecular weight of 1000, with a dimethylsiloxane to siloxane ratio of 30%) and 100 mL of toluene were mixed in a 250 mL three-necked flask equipped with a condenser reflux system. The flask was placed in an oil bath with magnetic stirring. 1.22 g (0.01 mol) of phenylboric acid was slowly added while stirring at room temperature. The mixture was stirred at room temperature for 30 minutes, then heated to 120°C and stirred at 120°C for 10 hours to obtain a crude product containing toluene as solvent. The crude product containing toluene was cooled to room temperature, filtered to remove unreacted phenylboric acid, and then the toluene solvent was removed by rotary evaporation. The product was then dried in a vacuum oven at 70°C for 24 hours to obtain a polyborosiloxane damping additive.

[0102] The polyborosiloxane damping additive obtained in this example was used to prepare a 2 mm thick damping silicone rubber required for the test. The raw material ratio and reaction conditions were the same as in Example 1 except that the polyborosiloxane damping additive was different.

[0103] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A polyborosiloxane damping additive for phenyl silicone rubber, characterized in that: The polyborosiloxane damping additive has a number average molecular weight of 1000 to 12000 and has a structure as shown in Formula I or Formula III: Formula I; Formula III; Wherein, R3 is selected from one of phenyl, biphenyl and anthracene, a is selected from a positive integer between 1 and 5, b:a≤50%, and the structural formula of A is shown in V: Formula V; In the formula, R1 and R2 are independently selected from one or a combination of methyl, phenyl, vinyl and hydrogen atoms, m:n≤30%, m≤100.

2. A polyborosiloxane damping additive for phenyl silicone rubber, characterized in that: The polyborosiloxane damping additive has a number average molecular weight of 1000 to 12000 and has a structure as shown in Formula II or Formula IV: Formula II; Formula IV; Wherein, R3 is selected from one of phenyl, biphenyl and anthracene, a is selected from a positive integer between 1 and 5, b:a≤50%, and the structural formula of A is shown in V: Formula V; In the formula, R1 and R2 are independently selected from one or a combination of methyl, phenyl, vinyl and hydrogen atoms, m:n≤30%, m≤100.

3. The polyborosiloxane damping additive according to claim 1 or 2, characterized in that: The viscosity of the polyborosiloxane damping additive is 100-20000 mPa·s.

4. The polyborosiloxane damping additive according to claim 1 or 2, characterized in that: The number average molecular weight of A is 1,000 to 10,000.

5. A method for preparing the polyborosiloxane damping additive according to any one of claims 1 to 4, characterized in that: The following steps are involved: The terminal hydroxyl polysiloxane is mixed with an organic solvent, and then a boron-containing aromatic compound is added. After uniform mixing, the mixture is heated for reaction to obtain a crude polyborosiloxane product. The crude polyborosiloxane product is subjected to rotary evaporation, dissolution, filtration, rotary evaporation and drying to obtain the polyborosiloxane damping additive.

6. The preparation method according to claim 5, wherein The hydroxyl ratio of the terminal hydroxyl polysiloxane to the boron-containing aromatic compound is 1:(0.2-3).

7. The preparation method according to claim 5, wherein The number average molecular weight of the hydroxyl-terminated polysiloxane is 1,000 to 10,000, and the structural formula of the hydroxyl-terminated polysiloxane is shown in Formula IV: Formula VI.

8. The preparation method according to claim 5, wherein The boron-containing aromatic compound includes at least one of phenylboronic acid, 1,4-phenyldiboronic acid, 1,3-phenyldiboronic acid, biphenyldiboronic acid, and anthracene-9,10-diboronic acid.

9. The preparation method according to claim 5, wherein The reaction temperature of the heating reaction is 90°C~150°C, and the reaction time is 8~24 h.

10. The preparation method according to claim 5, characterized in that The organic solvent includes at least one of toluene and xylene.

11. Use of the polyborosiloxane damping additive according to any one of claims 1 to 4 in the preparation of silicone rubber.

Images