High-damping polyborosiloxane, polyborosiloxane elastomer as well as preparation method and application of high-damping polyborosiloxane and polyborosiloxane elastomer

Abstract

The invention provides high-damping polyborosiloxane, a polyborosiloxane elastomer as well as a preparation method and application of the high-damping polyborosiloxane and the polyborosiloxane elastomer. The polyborosiloxane is prepared from the following raw materials in parts by weight: 5 to 50 parts of low-molecular-weight hydroxyl-terminated polysiloxane, 50 to 100 parts of high-molecular-weight hydroxyl-terminated polysiloxane and 0.02 to 5 parts of boric acid cross-linking agent. The polyborosiloxane elastomer comprises the following raw materials: a silicone rubber matrix, polyborosiloxane according to any one of claims 1-3, a cross-linking agent, a catalyst and an inhibitor. The polyborosiloxane and the polyborosiloxane elastomer are excellent in damping performance, the preparation method is simple and suitable for large-scale production, and the elastomer has wide potential in the fields of flexible electronics, shock absorption and noise reduction, impact protection, flexible display protection and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of organosilicon materials, and in particular to a high-damping polyborosiloxane, a polyborosiloxane elastomer, and a preparation method and application thereof. Background Art

[0002] Protective materials play a vital role in mitigating the effects of shock and vibration on industrial equipment, precision instruments, and the human body. In recent years, polyborosiloxane (PBSI) has been widely studied as an impact-resistant material due to its unique viscoelastic properties. PBSI, a viscous liquid at rest, rapidly hardens upon impact to withstand external shock, demonstrating excellent impact protection. Therefore, blending PBSI with other rubber materials is an effective strategy for improving the impact resistance of polymer materials.

[0003] However, the low damping factor of the polyborosiloxane and elastomer materials prepared by the above method at low temperatures or high frequencies limits their further application. Therefore, there is an urgent need to optimize the structure of polyborosiloxane to improve its damping performance over a wider temperature and frequency range. This could allow it to be combined with silicone rubber to prepare polyborosiloxane elastomer materials with high damping properties, further enhancing their impact resistance and shock absorption capabilities. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides the following technical solutions:

[0005] A polyborosiloxane, wherein the raw materials of the polyborosiloxane include: 5-50 parts by weight of a low-molecular-weight hydroxyl-terminated polysiloxane, 50-100 parts by weight of a high-molecular-weight hydroxyl-terminated polysiloxane, and 0.02-5 parts by weight of a boric acid crosslinking agent.

[0006] According to an embodiment of the present invention, the content of the low molecular weight hydroxyl-terminated polysiloxane is 10 parts by weight, 20 parts by weight, 30 parts by weight, 40 parts by weight, or 50 parts by weight.

[0007] According to an embodiment of the present invention, the content of the high molecular weight hydroxyl-terminated polysiloxane is 90 parts by weight, 80 parts by weight, 70 parts by weight, or 60 parts by weight.

[0008] According to an embodiment of the present invention, the content of the boric acid crosslinking agent is 0.1 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, or 4 parts by weight.

[0009] According to an embodiment of the present invention, the weight average molecular weight of the low molecular weight hydroxyl-terminated polysiloxane is 1200-18000, for example, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 11000, 12000, or 15000.

[0010] According to an embodiment of the present invention, the weight average molecular weight of the high molecular weight hydroxyl-terminated polysiloxane is 79,000 to 550,000, for example, 80,000, 100,000, 200,000, 300,000, 400,000, or 500,000.

[0011] According to an embodiment of the present invention, the weight ratio of the low molecular weight hydroxyl-terminated polysiloxane to the high molecular weight hydroxyl-terminated polysiloxane is 5-50:50-100, for example, 30:100, 50:100, or 31:100.

[0012] According to an embodiment of the present invention, the hydroxyl-terminated polysiloxane in the low molecular weight hydroxyl-terminated polysiloxane and the high molecular weight hydroxyl-terminated polysiloxane may be the same or different and independently selected from one or more of hydroxyl-terminated polydimethylsiloxane, hydroxyl-terminated polydimethyldiphenylsiloxane, hydroxyl-terminated polymethylphenylpolysiloxane and hydroxyl-terminated polycyanopropylmethylpolysiloxane.

[0013] According to an embodiment of the present invention, the boric acid crosslinking agent is selected from at least one or more of boric acid, tris(trimethylsilyl)borate, sodium tetraborate, lithium tetraborate, tetraborate amine, potassium tetraborate, trimethyl borate, triethyl borate, tripropyl borate, triisopropyl borate, tributyl borate, triisobutyl borate, 1,3-phenylenediboric acid, 1,4-phenylenediboric acid or biphenylboric acid.

[0014] According to an embodiment of the present invention, the damping factor of the polyborosiloxane is greater than 0.3 in the frequency range of 0.01 Hz to 50 Hz and / or in the temperature range of -20°C to 140°C. Exemplarily, at 0.01 Hz and 25°C, the damping factor of the polyborosiloxane is greater than 0.3, for example, 2.487, 2.153, or 2.562. Exemplarily, at 0.1 Hz and 25°C, the damping factor of the polyborosiloxane is greater than 0.3, for example, greater than 0.8, and for example, 0.913, 0.886, or 0.982. Exemplarily, at 1 Hz and 25°C, the damping factor of the polyborosiloxane elastomer is greater than 0.3, for example, greater than 0.6, and for example, 0.782, 0.698, or 0.803. Illustratively, at 10 Hz and 25° C., the damping factor of the polyborosiloxane elastomer is higher than 0.3, for example, greater than 0.5, and for example, 0.648, 0.582, or 0.681. Illustratively, at 50 Hz and 25° C., the damping factor of the polyborosiloxane elastomer is higher than 0.3, for example, greater than 0.4, and for example, 0.48, 0.42, or 0.562.

[0015] According to an embodiment of the present invention, the polyborosiloxane is a gel.

[0016] The present invention also provides a method for preparing the polyborosiloxane, which comprises: blending the raw materials of the polyborosiloxane and an organic solvent, removing the organic solvent, and continuing a high-temperature reaction to obtain the polyborosiloxane.

[0017] According to an embodiment of the present invention, the blending is carried out at a temperature below 100°C, preferably greater than 50°C and less than 100°C, such as 60°C or 80°C.

[0018] According to an embodiment of the present invention, the blending time is not less than 1 hour, for example, 1-2 hours.

[0019] According to an embodiment of the present invention, the blending or high-temperature reaction is carried out under mechanical stirring, and the stirring speed can be selected from conditions known in the art, such as 500 rpm.

[0020] According to an embodiment of the present invention, the organic solvent is one or more of dichloromethane, chloroform, ethyl acetate, butyl acetate, acetonitrile, toluene, benzene, ether, methanol, ethanol, isopropanol, acetone, butanone, cyclohexanone, tetrahydrofuran, n-hexane, cyclohexane, dioxane, and N,N-dimethylformamide.

[0021] The present invention also provides a polyborosiloxane elastomer. The raw materials of the polyborosiloxane elastomer include: a silicone rubber matrix, the polyborosiloxane, a crosslinking agent, a catalyst and an inhibitor.

[0022] According to an embodiment of the present invention, the raw materials of the polyborosiloxane elastomer include, by weight: 10-50 parts by weight of silicone rubber matrix, 90-50 parts by weight of polyborosiloxane, 0.1-10 parts by weight of crosslinking agent, 0.1-1 parts by weight of catalyst, and 0.1-1 parts by weight of inhibitor.

[0023] According to an embodiment of the present invention, in the raw materials of the polyborosiloxane elastomer, the silicone rubber matrix accounts for 20 parts by weight, 30 parts by weight, 40 parts by weight, and 50 parts by weight, calculated in parts by mass.

[0024] According to an embodiment of the present invention, in the raw materials of the polyborosiloxane elastomer, the amount of polyborosiloxane is 60 parts by weight, 70 parts by weight, or 80 parts by weight, calculated by parts by mass.

[0025] According to an embodiment of the present invention, in the raw materials of the polyborosiloxane elastomer, the crosslinking agent is 1 part by weight, 3 parts by weight, 5 parts by weight, 7 parts by weight, and 9 parts by weight.

[0026] According to an embodiment of the present invention, in parts by mass, the catalyst in the raw materials of the polyborosiloxane elastomer is, for example, 0.1 parts by weight, 0.2 parts by weight, 0.3 parts by weight, 0.4 parts by weight, 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, or 0.9 parts by weight.

[0027] According to an embodiment of the present invention, in the raw materials of the polyborosiloxane elastomer, the inhibitor is, for example, 0.1 part by weight, 0.2 part by weight, 0.3 part by weight, 0.4 part by weight, 0.5 part by weight, 0.6 part by weight, 0.7 part by weight, 0.8 part by weight, or 0.9 part by weight, calculated in parts by mass.

[0028] According to an embodiment of the present invention, the silicone rubber matrix can be any one of room temperature vulcanized silicone rubber, high temperature vulcanized silicone rubber, and addition type liquid silicone rubber. Exemplarily, the high temperature vulcanized silicone rubber is selected from polymethylvinylpolysiloxane with a molecular weight of 700,000 and a vinyl content of 0.16%.

[0029] According to an embodiment of the present invention, the crosslinking agent is selected from at least one of hydrogen-containing polydimethylsiloxane, hydrogen-containing polymethylethylsiloxane, hydrogen-containing polymethylphenylsiloxane, hydrogen-containing polymethylfluoropropylsiloxane, and tetraethyl silicate.

[0030] According to an embodiment of the present invention, in the raw material of the polyborosiloxane elastomer, the amount of the cross-linking agent used is 0.1-2 g, for example, 0.5 g, 1 g, or 1.5 g, in parts by mass.

[0031] According to an embodiment of the present invention, the catalyst is different depending on the different vulcanization methods of the silicone rubber matrix. For example, the catalyst is selected from at least one of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, Custer catalyst, and dibutyltin dilaurate.

[0032] According to an embodiment of the present invention, the inhibitor is selected from at least one of 2-methyl-3-alkyn-2-ol, 2-methyl-1-alkyn-3-ol, vinyl cyclohexanol, ethynyl cyclohexanol, dimethyl sulfoxide, phenylacetylene, and tert-butyl peroxide.

[0033] According to an embodiment of the present invention, the polyborosiloxane elastomer is composed of a permanently crosslinked polysiloxane network and a dynamically crosslinked polyborosiloxane network, thus having a dual network structure. In the present invention, the permanently crosslinked polysiloxane network is specifically a permanently crosslinked network formed by vulcanization crosslinking of a silicone rubber matrix, and the dynamically crosslinked polyborosiloxane network is specifically a polyborosiloxane network dynamically crosslinked by Si-O-B bonds, formed by the reaction of a boric acid crosslinker and a hydroxyl-terminated polysiloxane.

[0034] According to an embodiment of the present invention, the damping factor of the polyborosiloxane elastomer is higher than 0.3 in the frequency range of 0.01 Hz to 50 Hz and / or in the temperature range of -20°C to 140°C. Exemplarily, at 0.01 Hz and 25°C, the damping factor of the polyborosiloxane elastomer is higher than 0.3, for example, 0.851, 0.674, 0.541, or 0.561. Exemplarily, at 0.1 Hz and 25°C, the damping factor of the polyborosiloxane elastomer is higher than 0.3, for example, 0.435, 0.617, 0.468, or 0.488. Exemplarily, at 1 Hz and 25°C, the damping factor of the polyborosiloxane elastomer is higher than 0.3, for example, 0.356, 0.499, 0.432, or 0.508. Exemplarily, at 10 Hz and 25° C., the damping factor of the polyborosiloxane elastomer is greater than 0.3, such as 0.361, 0.464, 0.501, or 0.378. Exemplarily, at 50 Hz and 25° C., the damping factor of the polyborosiloxane elastomer is greater than 0.3, such as 0.321, 0.348, 0.360, or 0.330.

[0035] The inventors discovered that the presence of a permanently cross-linked polysiloxane network in the silicone rubber matrix provides a stable framework for the dynamically cross-linked polyborosiloxane, enabling the material to exhibit good elastic behavior and reversible deformation. The high-damping polyborosiloxane of the present invention exhibits excellent damping properties over a wide temperature range and frequency range due to the presence of internal friction between molecular chains and the dissociation and rearrangement of BO dynamic bonds.

[0036] The present invention also provides a method for preparing the polyborosiloxane elastomer, comprising the following steps:

[0037] (1) dissolving the raw material of the polyborosiloxane elastomer in a solvent and mixing them uniformly, and then removing the solvent to obtain a mixture;

[0038] (2) The mixture of step (1) is cured at 60-120° C. to obtain the polyborosiloxane elastomer.

[0039] According to an embodiment of the present invention, in step (1), the solvent is selected from at least one or more of N,N-dimethylformamide, dichloromethane, chloroform, ethyl acetate, butyl acetate, toluene, benzene, o-xylene, m-xylene, p-xylene, n-hexane, petroleum ether, ethanol, methanol, acetone, isopropanol, cyclohexanone, and dioxane.

[0040] According to an embodiment of the present invention, in step (1), the mixing process is carried out under stirring or ultrasonic conditions. Exemplarily, the stirring is, for example, mechanical stirring or magnetic stirring at room temperature, and the stirring time is 0.5-2h. The ultrasonication is, for example, performed in an ultrasonic cleaning machine, and the ultrasonic power is 100-300W, and the ultrasonication time is 1h.

[0041] According to an embodiment of the present invention, in step (1), the mass ratio of the total mass of the raw materials of the polyborosiloxane elastomer to the solvent is 1:0.5-50, for example, 1:0.5, 1:1, 1:5, 1:10, 1:20, 1:50.

[0042] According to an embodiment of the present invention, in step (1), the solvent can be removed by methods known in the art, such as volatilization.

[0043] According to an embodiment of the present invention, in step (2), the mixture may be placed in a mold before curing.

[0044] According to an embodiment of the present invention, in step (2), the curing time is, for example, 1-12 hours.

[0045] The present invention also provides applications of the polyborosiloxane and / or polyborosiloxane elastomer in the fields of flexible electronics, vibration and noise reduction, impact protection, and flexible display protection.

[0046] Beneficial effects:

[0047] The present invention prepares a high-damping polyborosiloxane elastomer, which is composed of a permanently cross-linked polyborosiloxane network and a dynamically cross-linked polyborosiloxane network, resulting in an elastomeric material with a dual-network structure. Furthermore, the two networks have excellent compatibility, resulting in the resulting elastomeric material exhibiting good optical transparency, mechanical properties, damping performance, and maintaining good stability over a long period of time. Experimental results show that the polyborosiloxane prepared by the present invention has a damping factor greater than 0.3 in the frequency range of 0.01 Hz to 50 Hz and / or the temperature range of -20°C to 140°C. The polyborosiloxane elastomer containing this polyborosiloxane can also have a damping factor greater than 0.3 in the frequency range of 0.01 Hz to 50 Hz and / or the temperature range of -20°C to 140°C, demonstrating superior damping performance and impact protection compared to existing polyborosiloxane-containing elastomers and conventional polysiloxane damping elastomers.

[0048] The polyborosiloxane and polyborosiloxane elastomer of the present invention have excellent damping properties, simple preparation methods, and are suitable for large-scale production. The elastomer has broad potential in the fields of flexible electronics, vibration and noise reduction, impact protection, and flexible display protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 1 is the modulus-temperature curve of the polyborosiloxane of Example 1 and Comparative Example 1;

[0050] Figure 2 1 is the loss factor-temperature curve of the polyborosiloxane of Example 1 and Comparative Example 1;

[0051] Figure 3 The modulus and loss factor-temperature curves of the polyborosiloxane elastomer of Example 2;

[0052] Figure 4 The modulus and loss factor-frequency curves of the polyborosiloxane elastomer of Example 2 are shown. DETAILED DESCRIPTION

[0053] The technical solutions of the present invention will be described in further detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are encompassed within the scope of protection that the present invention is intended to protect.

[0054] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0055] Example 1: Preparation of high-damping polyborosiloxane:

[0056] Dissolve 0.4g of boric acid in 10ml of methanol, and dissolve 30g of a low-molecular-weight hydroxyl-terminated polydimethylsiloxane (weight-average molecular weight of 4200) and 100g of a high-molecular-weight hydroxyl-terminated polydimethylsiloxane (weight-average molecular weight of 110,000) in 100ml of isopropanol. Add the boric acid methanol solution dropwise to the isopropanol solution of the two hydroxyl-terminated polydimethylsiloxanes. Stir and react at 60°C for 2 hours, then raise the temperature to 120°C, remove the solvent, and continue the reaction in a dry environment for 12 hours to obtain a high-damping polyborosiloxane, which is a gel material.

[0057] Example 2: Preparation of high-damping polyborosiloxane elastomer:

[0058] 10 g of the high-damping polyborosiloxane prepared in Example 1, 1.8 g of polymethylvinylsiloxane, 0.2 g of hydrogen-containing polysiloxane, 0.02 g of Custer catalyst, 0.01 g of ethynylcyclohexanol, and 30 ml of o-xylene were stirred and uniformly mixed, then poured into a mold. After evaporation to remove the solvent, the mixture was transferred to a 100° C. forced air oven and heated for curing for 3 h to obtain a polyborosiloxane elastomer.

[0059] Example 3: Preparation of high-damping polyborosiloxane:

[0060] 10 g of trimethyl borate was dissolved in 150 ml of methanol, 1000 g of hydroxyl-terminated polydimethylsiloxane with a weight-average molecular weight of 4200 and 2000 g of hydroxyl-terminated polydimethylsiloxane with a weight-average molecular weight of 190,000 were dissolved in 2000 ml of isopropanol, the methanol solution of trimethyl borate was added dropwise to the hydroxyl-terminated polydimethylsiloxane solution, the mixture was stirred at 60 ° C for 2 h, then the temperature was raised to 120 ° C, the solvent was removed, and the reaction was continued in a dry environment for 12 h to obtain a high-damping polyborosiloxane gel material.

[0061] Example 4: Preparation of high-damping polyborosiloxane:

[0062] 5g of triisopropyl borate was dissolved in 100ml of methanol, 250g of hydroxyl-terminated polydimethylsiloxane with a weight-average molecular weight of 4200 and 800g of hydroxyl-terminated polydimethylsiloxane with a weight-average molecular weight of 230000 were dissolved in 1200ml of isopropanol, the methanol solution of triisopropyl borate was added dropwise to the isopropanol solutions of the two hydroxyl-terminated polydimethylsiloxanes, the mixture was stirred at 60°C for 2h, then the temperature was raised to 120°C, the solvent was removed, and the reaction was continued in a dry environment for 12h to obtain high-damping polyborosiloxane, which is a gel material.

[0063] Example 5: Preparation of high-damping polyborosiloxane elastomer

[0064] 12 g of the high-damping polyborosiloxane prepared in Example 3, 2 g of polymethylvinylpolysiloxane (molecular weight 700,000, vinyl content 0.16%), and 0.02 g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane were mixed uniformly in an internal mixer, transferred to a metal mold, and press-cured at 160° C. for 20 min to obtain a high-damping polyborosiloxane elastomer.

[0065] Example 6: Preparation of high-damping polyborosiloxane elastomer:

[0066] 360 g of the high-damping polyborosiloxane prepared in Example 3, 60 g of polymethylvinylsiloxane, 6.0 g of hydrogen-containing polysiloxane, 0.6 g of Custer catalyst, 0.3 g of ethynylcyclohexanol, and 180 ml of o-xylene were stirred and uniformly mixed, then poured into a mold. After evaporation to remove the solvent, the mixture was transferred to a 100° C. forced air oven and heated for curing for 3 hours to obtain a polyborosiloxane elastomer.

[0067] Example 7: Preparation of high-damping polyborosiloxane elastomer

[0068] 9 g of the high-damping polyborosiloxane prepared in Example 4, 2 g of room temperature vulcanized silicone rubber, 0.01 g of ethyl orthosilicate, and 0.02 g of dibutyltin dilaurate were mixed evenly in an open mill and then transferred to a metal mold. After curing at room temperature for 72 hours, a high-damping polyborosiloxane elastomer was obtained.

[0069] Comparative Example 1: Preparation of conventional polyborosiloxane:

[0070] Dissolve 0.50g of boric acid in 5ml of isopropanol to obtain a methanol solution of boric acid. Dissolve 50g of hydroxyl-terminated polydimethylsiloxane with a weight-average molecular weight of 4200 in 50ml of methanol to obtain a toluene solution of hydroxyl-terminated polydimethylsiloxane. Add the methanol solution of phenyldiboric acid dropwise to the methanol solution of hydroxyl-terminated polydimethylsiloxane, stir at 60°C for 2h, then heat to 120°C, remove the solvent, and continue the reaction in a dry environment for 12h to obtain conventional polyborosiloxane, which is a gel material.

[0071] Comparative Example 2: Preparation of polyborosiloxane:

[0072] Dissolve 1.2g of 1,4-phenylenediboronic acid in 5ml of methanol to obtain a methanol solution of boric acid. Dissolve 50g of hydroxyl-terminated polydimethylsiloxane with a weight-average molecular weight of 4200 in 50ml of methanol to obtain a toluene solution of hydroxyl-terminated polydimethylsiloxane. Add the methanol solution of boric acid dropwise to the toluene solution of hydroxyl-terminated polydimethylsiloxane, stir at 60°C for 2h, then heat to 120°C, remove the solvent, and continue the reaction in a dry environment for 12h to obtain conventional polyborosiloxane, which is a gel material.

[0073] Comparative Example 3: Preparation of conventional polyborosiloxane elastomer:

[0074] 10 g of conventional polyborosiloxane prepared in Comparative Example 1, 9.0 g of polymethylvinylsiloxane, 1.0 g of hydrogen-containing polysiloxane, 0.02 g of Custer catalyst, 0.01 g of ethynylcyclohexanol, and 30 ml of o-xylene were stirred and evenly mixed, then poured into a mold. After evaporation to remove the solvent, the mixture was transferred to a 100° C. forced air oven and heated for curing for 3 hours to obtain a conventional polyborosiloxane elastomer.

[0075] Comparative Example 4: Preparation of conventional polyborosiloxane elastomer:

[0076] 12 g of conventional polyborosiloxane prepared in Comparative Example 1, 7 g of polymethylvinylsiloxane, 0.7 g of hydrogen-containing polysiloxane, 0.02 g of Custer catalyst, 0.01 g of ethynylcyclohexanol, and 30 ml of o-xylene were stirred and evenly mixed, then poured into a mold. After evaporation to remove the solvent, the mixture was transferred to a 100° C. forced air oven and heated for curing for 3 hours to obtain a conventional polyborosiloxane elastomer.

[0077] Comparative Example 5: Preparation of conventional polyborosiloxane elastomer:

[0078] 10 g of conventional polyborosiloxane prepared in Comparative Example 2, 9.0 g of polymethylvinylsiloxane, 1.0 g of hydrogen-containing polysiloxane, 0.02 g of Custer catalyst, 0.01 g of ethynylcyclohexanol, and 25 ml of o-xylene were stirred and evenly mixed, then poured into a mold. After evaporation to remove the solvent, the mixture was transferred to a 100° C. forced air oven and heated for curing for 3 hours to obtain a conventional polyborosiloxane elastomer.

[0079] Comparative Example 6: Preparation of a silicone rubber elastomer without polyborosiloxane:

[0080] 9.0 g of polymethylvinylsiloxane, 1.0 g of hydrogen-containing polysiloxane, 0.02 g of Custer catalyst, 0.01 g of ethynylcyclohexanol, and 10 ml of o-xylene were stirred and evenly mixed, and then poured into a mold. After evaporation to remove the solvent, the mixture was transferred to a 100° C. forced air oven and heated for curing for 3 hours to obtain a silicone rubber elastomer material that does not contain polyborosiloxane.

[0081] Comparative Example 7: Preparation of polyborosiloxane elastomer

[0082] 10 g of the high-damping polyborosiloxane prepared in Example 4, 9.0 g of polymethylvinylsiloxane, 1.0 g of hydrogen-containing polysiloxane, 0.02 g of Custer catalyst, 0.01 g of ethynylcyclohexanol, and 25 ml of o-xylene were stirred and mixed evenly, and then poured into a mold. After evaporation to remove the solvent, the mixture was transferred to a blast oven at 100° C. and heated and cured for 3 h to obtain a polyborosiloxane elastomer.

[0083] Performance test example 1:

[0084] Dynamic mechanical properties of Examples 1-4 and Comparative Examples 1-6 were tested using a HAAKE MARS60 rheometer to study the viscoelasticity and damping properties of the samples. The loss factors (damping factors) of the Examples and Comparative Examples at different frequencies are shown in Table 1.

[0085] Table 1: Dynamic mechanical test results

[0086]

[0087]

[0088] As can be seen from Table 1, the polyborosiloxane elastomer prepared in this application has a significantly improved loss factor compared to conventionally prepared ones, and has a higher damping factor over a wide frequency range. For example, compared with Examples 1, 3, and 4 and Comparative Examples 1-2, the high-damping polyborosiloxane of Examples 1, 3, and 4 has a higher damping factor over the entire frequency range than conventional polyborosiloxane, showing better damping performance. For example, compared with Examples 2, 5, 6, and 7 and Comparative Examples 3 and 5, the damping factors of Examples 2, 5, 6, and 7 are all higher than 0.3 over a wide frequency range, showing better damping performance; Comparative Example 6 does not have the addition of polyborosiloxane, and its damping performance over the entire frequency range is very poor. Due to the introduction of high-damping polyborosiloxane content, the damping factor of Comparative Example 7 is lower than 0.3, but its damping performance in the high frequency range is far better than that of Comparative Example 3 with the same amount of polyborosiloxane introduced.

[0089] The loss factors of the polyborosiloxanes of Examples 1-2 and Comparative Example 1 at different temperatures at 1 Hz were studied using a HAAKE MARS60 rheometer. Figure 1 is the modulus-temperature curve of Example 1 and Comparative Example 1, Figure 2 The loss factor-temperature curves of Example 1 and Comparative Example 1 are shown. It can be seen that after structural design, Example 1 maintains a stable storage modulus within the test temperature range while maintaining a damping factor higher than 0.4, and its damping performance is far superior to that of Comparative Example 1.

[0090] like Figure 3 The graph shows the relationship between the storage modulus, loss modulus, and dissipation factor of Example 2 at 1 Hz and temperature. The storage modulus remains above 20,000 Pa across the wide temperature range tested, demonstrating good stability. The storage modulus is consistently higher than the loss modulus. Furthermore, the dissipation factor of the elastomeric material remains above 0.3 within the tested temperature range of -20°C to 145°C, demonstrating good damping performance.

[0091] Figure 4The modulus-frequency curve of Example 2 at 25°C from 0.01Hz to 50Hz shows that the storage modulus is always higher than the loss modulus within the test range, indicating good stability; the damping factor is always higher than 0.3 within the test range, indicating excellent damping performance over a wide frequency range.

[0092] The above experimental results show that the high-damping polyborosiloxane prepared in the present invention has higher damping performance than ordinary polyborosiloxane and polydiborosiloxane. Therefore, the elastomer modified with the high-damping polyborosiloxane also has excellent damping performance in a wide frequency and temperature range.

[0093] Performance test example 2:

[0094] The cushioning performance and impact protection performance of Examples 2-3 and Comparative Examples 1, 2, and 7 of the same thickness under the same impact conditions were studied using a falling ball impact device equipped with a force sensor.

[0095] Test conditions: Samples of equal thickness are applied as protective films to the force sensor. A 30g steel ball is dropped from a height of 30cm to impact the protective films, and the mechanical signal transmitted through the impact film is recorded. A blank sample is tested directly on the sensor without the protective film.

[0096] Table 2: Drop ball impact test results

[0097]

[0098] As shown in Table 2, the high-damping silicone rubber prepared according to the present invention exhibits excellent impact protection, effectively mitigating damage caused by impact forces. Comparing Example 2 with Comparative Example 1, the maximum penetration force decreased from 290 N to 170 N, and from 3300 N in the blank sample to 170 N. This demonstrates that the high-damping polyborosiloxane elastomer prepared according to the present invention outperforms even conventional polyborosiloxane materials, demonstrating its broad potential for application in impact protection.

[0099] The above describes exemplary embodiments of the present invention. However, the scope of protection of this application is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A polyborosiloxane, characterized in that The raw materials of the polyborosiloxane include: 5-50 parts by weight of low molecular weight hydroxyl-terminated polysiloxane, 50-100 parts by weight of high molecular weight hydroxyl-terminated polysiloxane, and 0.02-5 parts by weight of a boric acid crosslinking agent.

2. The polyborosiloxane according to claim 1, wherein The weight average molecular weight of the low molecular weight hydroxyl-terminated polysiloxane is 1200 to 18000; The weight average molecular weight of the high molecular weight hydroxyl-terminated polysiloxane is 79,000 to 550,000; The weight ratio of the low molecular weight hydroxyl-terminated polysiloxane to the high molecular weight hydroxyl-terminated polysiloxane is 5-50:50-100.

3. The polyborosiloxane according to claim 1, wherein The hydroxyl-terminated polysiloxanes in the low molecular weight hydroxyl-terminated polysiloxane and the high molecular weight hydroxyl-terminated polysiloxane may be the same or different and are independently selected from one or more of hydroxyl-terminated polydimethylsiloxane, hydroxyl-terminated polydimethyldiphenylsiloxane, hydroxyl-terminated polymethylphenylpolysiloxane and hydroxyl-terminated polycyanopropylmethylpolysiloxane; The boric acid crosslinking agent is selected from at least one or more of boric acid, tris(trimethylsilyl)borate, sodium tetraborate, lithium tetraborate, tetraborate amine, potassium tetraborate, trimethyl borate, triethyl borate, tripropyl borate, triisopropyl borate, tributyl borate, triisobutyl borate, 1,3-phenylenediboric acid, 1,4-phenylenediboric acid or biphenylboric acid; The damping factor of the polyborosiloxane is higher than 0.3 in the frequency range of 0.01 Hz to 50 Hz and / or in the temperature range of -20°C to 140°C; The polyborosiloxane is a gel.

4. The method for preparing the polyborosiloxane according to any one of claims 1 to 3, characterized in that: The preparation method comprises: mixing raw materials of polyborosiloxane and an organic solvent, removing the organic solvent and continuing high-temperature reaction to obtain polyborosiloxane.

5. The preparation method according to claim 4, characterized in that The blending is carried out at a temperature below 100° C. The blending time is not less than 1 hour; The organic solvent is one or more of dichloromethane, chloroform, ethyl acetate, butyl acetate, acetonitrile, toluene, benzene, ether, methanol, ethanol, isopropanol, acetone, butanone, cyclohexanone, tetrahydrofuran, n-hexane, cyclohexane, dioxane, and N,N-dimethylformamide.

6. A polyborosiloxane elastomer, characterized in that The raw materials of the polyborosiloxane elastomer include: a silicone rubber matrix, the polyborosiloxane according to any one of claims 1 to 3, a crosslinking agent, a catalyst and an inhibitor; The raw materials of the polyborosiloxane elastomer include, by weight, 10-50 parts by weight of silicone rubber matrix, 90-50 parts by weight of polyborosiloxane, 0.1-10 parts by weight of crosslinking agent, 0.1-1 parts by weight of catalyst, and 0.1-1 parts by weight of inhibitor.

7. The polyborosiloxane elastomer according to claim 6, characterized in that The silicone rubber matrix is ​​any one of room temperature vulcanized silicone rubber, high temperature vulcanized silicone rubber, and addition type liquid silicone rubber; The crosslinking agent is selected from at least one of hydrogen-containing polydimethylsiloxane, hydrogen-containing polymethylethylsiloxane, hydrogen-containing polymethylphenylsiloxane, hydrogen-containing polymethylfluoropropylsiloxane, and tetraethyl silicate; In the raw materials of the polyborosiloxane elastomer, the amount of the crosslinking agent is 0.1-2g by mass; The catalyst is selected from at least one of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, Custer catalyst, and dibutyltin dilaurate; The inhibitor is selected from at least one of 2-methyl-3-alkyn-2-ol, 2-methyl-1-alkyn-3-ol, vinyl ring, ethynyl cyclohexanol, dimethyl sulfoxide, phenylacetylene, and tert-butyl peroxide; In the frequency range of 0.01 Hz to 50 Hz and / or in the temperature range of -20°C to 140°C, the damping factor of the polyborosiloxane elastomer is higher than 0.

3.

8. The method for preparing the polyborosiloxane elastomer according to claim 6 or 7, characterized in that: The following steps are involved: (1) dissolving the raw material of the polyborosiloxane elastomer in a solvent and mixing them uniformly, and then removing the solvent to obtain a mixture; (2) The mixture of step (1) is cured at 60-120° C. to obtain the polyborosiloxane elastomer.

9. The preparation method according to claim 8, characterized in that In step (1), the solvent is selected from at least one or more of N,N-dimethylformamide, dichloromethane, chloroform, ethyl acetate, butyl acetate, toluene, benzene, o-xylene, m-xylene, p-xylene, n-hexane, petroleum ether, ethanol, methanol, acetone, isopropanol, cyclohexanone, and dioxane; In step (1), the mass ratio of the total mass of the raw materials of the polyborosiloxane elastomer to the mass ratio of the solvent is 1:0.5-50; In step (2), the curing time is, for example, 1-12 hours.

10. Use of the polyborosiloxane according to any one of claims 1 to 3 and / or the polyborosiloxane elastomer according to claim 6 or 7 in the fields of flexible electronics, vibration and noise reduction, impact protection, and flexible display protection.

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