A silicone rubber composition and use thereof

Abstract

The present application relates to a kind of silicone rubber compositions and its application, and it includes A component and B component, the A component includes the polysiloxane of hydroxyl group, the B component includes polysiloxane isocyanate;Wherein, the polysiloxane isocyanate has following structure.The silicone rubber composition of an embodiment of the present application can be used to prepare silicone rubber, and the poor mechanical property of silicone rubber is improved.

Description

Technical Field

[0001] This invention relates to isocyanates, and more particularly to a polysiloxane isocyanate and its applications. Background Technology

[0002] Silicone rubber possesses excellent heat resistance, cold resistance, dielectric properties, ozone resistance, and atmospheric aging resistance. Its outstanding properties allow for a wide operating temperature range, from -60℃ (or lower) to 250℃ (or higher) for extended periods. However, its tensile strength and tear strength are relatively poor, and its physical and mechanical properties at room temperature are inferior to most synthetic rubbers. Furthermore, except for nitrile and fluorosilicone rubbers, general silicone rubbers exhibit poor oil and solvent resistance. Therefore, silicone rubber is not suitable for general applications, but it is highly suitable for many specific uses. When silicone rubber is used as a foaming material in automotive power battery encapsulation, its poor processability presents a significant technical challenge.

[0003] Silicone rubber typically uses fumed silica as a reinforcing material to enhance the sealant's tensile strength, elongation at break, and other mechanical properties. However, if the specific surface area, volatility, or other properties of fumed silica are inappropriate, it may lead to problems such as a shortened shelf life and a rough appearance of the sealant. Furthermore, excessive addition can cause problems during application, such as thickening of the adhesive and poor extrudability.

[0004] Room temperature vulcanizing silicone rubber exhibits excellent heat resistance, cold resistance, and dielectric properties after complete vulcanization. Its only drawback is relatively low mechanical strength. While suitable for casting and coating, its use as an organosilicone adhesive is limited by its inherent structure and chemical bonds. Compared to polyurethane and epoxy adhesives, it suffers from lower mechanical strength and poorer bonding performance, thus limiting its application in fields demanding high mechanical and bonding properties. For instance, under prolonged high-temperature conditions, the performance of ordinary organosilicone adhesives degrades rapidly, failing to meet high-temperature resistance requirements. Summary of the Invention

[0005] To overcome at least one of the defects of the prior art, in a first aspect, one embodiment of the present invention provides a silicone rubber composition comprising component A and component B, wherein component A comprises a hydroxyl-containing polysiloxane, and component B comprises a polysiloxane isocyanate; wherein the polysiloxane isocyanate has the following structure:

[0006]

[0007] R1 and R2 are independently selected from hydrogen atoms, halogen atoms, alkyl groups containing 1 to 18 carbon atoms, alkoxy groups containing 1 to 18 carbon atoms, or aryl groups containing 6 to 12 carbon atoms;

[0008] X is selected from alkylene containing 1 to 18 carbon atoms, cycloalkylene containing 4 to 8 carbon atoms, or substituted or unsubstituted arylene containing 6 to 18 carbon atoms, wherein the substituent of the substituted arylene is selected from one or more of phenyl, halogen atom, methyl, methoxy, ethyl, and ethoxy.

[0009] Y is absent or selected from alkylene groups containing 1 to 18 carbon atoms, substituted or unsubstituted aryl groups containing 6 to 18 carbon atoms, wherein the substituent of the substituted aryl group is selected from one or more of phenyl, halogen, methoxy, ethyl, and allyl.

[0010] Secondly, one embodiment of the present invention provides a silicone rubber prepared from the above-described composition.

[0011] Thirdly, one embodiment of the present invention provides a polysiloxane isocyanate having the following structure:

[0012]

[0013] R1 and R2 are independently selected from hydrogen atoms, halogen atoms, alkyl groups containing 1 to 18 carbon atoms, alkoxy groups containing 1 to 18 carbon atoms, or aryl groups containing 6 to 12 carbon atoms;

[0014] X is selected from alkylene containing 1 to 18 carbon atoms, cycloalkylene containing 4 to 8 carbon atoms, or substituted or unsubstituted arylene containing 6 to 18 carbon atoms, wherein the substituent of the substituted arylene is selected from one or more of phenyl, halogen atom, methyl, methoxy, ethyl, and ethoxy.

[0015] Y is absent or selected from alkylene groups containing 1 to 18 carbon atoms, substituted or unsubstituted aryl groups containing 6 to 18 carbon atoms, wherein the substituent of the substituted aryl group is selected from one or more of phenyl, halogen, methoxy, ethyl, and allyl.

[0016] Fourthly, one embodiment of the present invention provides a method for preparing the above-mentioned polysiloxane isocyanate, comprising reacting a polysiloxane containing active hydrogen with phosgene and a diamine to obtain the polysiloxane isocyanate.

[0017] Fifthly, one embodiment of the present invention provides the application of the above-described polysiloxane isocyanate in the preparation of silicone rubber.

[0018] The silicone rubber composition of one embodiment of the present invention can be used to prepare silicone rubber, thereby improving the disadvantage of poor mechanical properties of silicone rubber. Detailed Implementation

[0019] Typical embodiments embodying the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various variations in different embodiments without departing from the scope of the present invention, and the description herein is for illustrative purposes only and not intended to limit the present invention.

[0020] One embodiment of the present invention provides a polysiloxane isocyanate having the following structure:

[0021]

[0022] R1 and R2 are independently selected from hydrogen atoms, halogen atoms, alkyl groups containing 1 to 18 carbon atoms, alkoxy groups containing 1 to 18 carbon atoms, or aryl groups containing 6 to 12 carbon atoms;

[0023] X is selected from alkylene containing 1 to 18 carbon atoms, cycloalkylene containing 4 to 8 carbon atoms, or substituted or unsubstituted arylene containing 6 to 18 carbon atoms. The substituent of the substituted arylene in the X group is selected from one or more of phenyl, halogen atom, methyl, methoxy, ethyl, and ethoxy.

[0024] Y is absent or selected from alkylene groups containing 1 to 18 carbon atoms, substituted or unsubstituted aryl groups containing 6 to 18 carbon atoms, and the substituents of the substituted aryl groups in Y are selected from one or more of phenyl, halogen, methoxy, ethyl, and allyl.

[0025] In one embodiment, the polysiloxane isocyanate is prepared by reacting a polysiloxane containing active hydrogen with phosgene and a diamine; wherein the polysiloxane containing active hydrogen has the following structure:

[0026]

[0027] R1 and R2 are independently selected from hydrogen atoms, halogen atoms, alkyl groups containing 1 to 18 carbon atoms, alkoxy groups containing 1 to 18 carbon atoms, or aryl groups containing 6 to 12 carbon atoms;

[0028] Y is absent or selected from alkylene groups containing 1 to 18 carbon atoms, substituted or unsubstituted aryl groups containing 6 to 18 carbon atoms, and the substituents of the substituted aryl groups in Y are selected from one or more of phenyl, halogen, methoxy, ethyl, and allyl.

[0029] In one embodiment, the number of carbon atoms in the alkyl or alkoxy groups of R1 and R2 in the polysiloxane isocyanate or polysiloxane structure containing active hydrogen is 1 to 18, preferably 1 to 12, for example 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12.

[0030] In one embodiment, the number of carbon atoms contained in the aryl groups of R1 and R2 in the polysiloxane isocyanate or polysiloxane structure containing active hydrogen can be 6, 7, 8, 9 or 10.

[0031] In one embodiment, the halogen atoms of R1 and R2 in the polysiloxane isocyanate or polysiloxane structure containing active hydrogen can be fluorine, chlorine, bromine or iodine, and more specifically chlorine or fluorine.

[0032] In one embodiment, R1 and R2 in the polysiloxane isocyanate or polysiloxane structure containing active hydrogen are both methyl groups.

[0033] In one embodiment, n in the polysiloxane isocyanate or polysiloxane structure containing active hydrogen is selected from 20 to 180; further, n is selected from 35 to 155, for example n can be 25, 30, 40, 50, 60, 80, 100, 120, 130, or 150.

[0034] In one embodiment, the Y in the polysiloxane isocyanate or the polysiloxane structure containing active hydrogen is absent or selected from the following structures:

[0035]

[0036] Among them, Y1 and Y2 are each independently hydrogen, methoxy or allyl, and R3 is -CH2-CH2-, -CH2-CH2-CH2- or -CH(CH3)CH2-.

[0037] In one embodiment, the Y in the polysiloxane isocyanate or the polysiloxane structure containing active hydrogen is absent or selected from the following structures:

[0038]

[0039] Wherein, Y1 is hydrogen, methoxy, or allyl.

[0040] In one embodiment, in the polysiloxane isocyanate structure, the number of carbon atoms contained in the alkylene group of X can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18.

[0041] In one embodiment, in the polysiloxane isocyanate structure, the number of carbon atoms contained in the cyclohexene alkyl group of X can be 4, 5, 6, 7 or 8, for example X can be cyclohexene (e.g. 1,4-cyclohexene).

[0042] In one embodiment, in the polysiloxane isocyanate structure, the number of carbon atoms contained in the substituted or unsubstituted aryl group of X can be 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18.

[0043] In one embodiment, in the polysiloxane isocyanate structure, X is selected from phenylene (e.g., ), methylphenylene (e.g.) ), hexylene (e.g., -(CH2)6-), -phenylene-CH2-phenylene- (e.g.) ), -cyclohexylene-CH2-cyclohexylene- (e.g.) ), 1,3,3-trimethylcyclohexylmethyl (e.g.) ).

[0044] In one embodiment, the polysiloxane isocyanate is selected from the following structures:

[0045]

[0046]

[0047] In one embodiment, the viscosity of the polysiloxane containing active hydrogen can be 2–330,000 mPa·s, more specifically 700–10,000 mPa·s, for example 10 mPa·s, 50 mPa·s, 100 mPa·s, 500 mPa·s, 750 mPa·s, 1000 mPa·s, 1500 mPa·s, 5000 mPa·s, 10000 mPa·s, 50000 mPa·s, 100000 mPa·s, 150000 mPa·s, 200000 mPa·s, 250000 mPa·s, and 300000 mPa·s. The above viscosities are measured at 25°C using a rotor viscometer or a cone-plate viscometer.

[0048] In one embodiment, the polysiloxane containing active hydrogen may be one or more of eugenol-terminated polysiloxane (Ⅳ), 4-allylphenol-terminated polysiloxane (Ⅴ), and hydroxyl-terminated polysiloxane (Ⅵ).

[0049]

[0050]

[0051] In one embodiment, the polysiloxane containing active hydrogen can be an existing commercial product, such as hydroxyl-terminated polydimethylsiloxane; or it can be prepared from existing products, for example, by an addition reaction (alkylation reaction of the double bond with hydride) between a phenolic compound containing a double bond and a polysiloxane with a terminal silicon-hydrogen bond (Si-H). The phenolic compound containing a double bond includes one or more of 4-vinylphenol, 4-allylphenol, 2-allylphenol, 3-allylphenol, eugenol (4-allyl-2-methoxyphenol), 4-allyl-2,6-dimethoxyphenol, and 4-isopropenylphenol.

[0052] In one embodiment, the molar number of phosgene is 1.1 to 1.5 times, more preferably 1.15 to 1.3 times, for example 1.2 times, 1.25 times, 1.35 times, or 1.4 times, the sum of the molar numbers of the diamine and the polysiloxane containing active hydrogen.

[0053] In one embodiment, the diamine includes one or more of 4,4'-diaminodiphenylmethane (MDA), 5-amino-1,3,3-trimethylcyclohexylmethane (IPDA), 4,4'-diaminodicyclohexylmethane (HMDA), toluenediamine (TDA), and hexamethylenediamine (HDA). Further, the diamine includes one or more of toluenediamine, 4,4'-diaminodiphenylmethane, and hexamethylenediamine.

[0054] One embodiment of the present invention provides a method for preparing the above-mentioned polysiloxane isocyanate by phosgenation, that is, by reacting a polysiloxane containing active hydrogen with phosgene and a diamine to prepare polysiloxane isocyanate.

[0055] In one implementation, the phosgenation method can employ existing processes.

[0056] In one embodiment, the reaction equation for the polysiloxane containing active hydrogen with phosgene and a diamine is as follows, wherein the polysiloxane containing active hydrogen is an eugenol-terminated polysiloxane, and the diamine is MDA.

[0057]

[0058] In one embodiment, a polysiloxane containing active hydrogen, phosgene, and a diamine are subjected to a cold phosgene reaction at a temperature of 0–70°C; subsequently, the system temperature is raised to 80–220°C for a thermal phosgene reaction.

[0059] In one embodiment, the temperature of the cold photochemical vaporization reaction can be 3°C, 5°C, 10°C, 20°C, 25°C, 30°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, or 70°C.

[0060] In one embodiment, the time for the cold photochemical reaction can be 0.5 to 3 hours, for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours, or 3 hours.

[0061] In one embodiment, the temperature of the thermophotovaporization reaction can be 90°C, 100°C, 120°C, 150°C, 155°C, 160°C, 165°C, 180°C, 200°C, or 210°C.

[0062] In one embodiment, the time for the thermophotovaporization reaction can be 1 to 2 hours, for example, 1 hour, 1.5 hours, or 2 hours.

[0063] In one embodiment, the solvent used in the reaction system for preparing polysiloxane isocyanate can be an inert solvent capable of dissolving polysiloxanes, diamines, phosgene, and polysiloxane isocyanates containing active hydrogen; the inert solvent may include one or more of dichloromethane, dichloroethane, trichloroethane, tetrachloroethane, pentachloroethane, hexachloroethane, dichloroethylene, chlorobenzene, o-dichlorobenzene, toluene, and xylene; further, the solvent may be one or more of o-dichlorobenzene, chlorobenzene, and dichloromethane.

[0064] In one embodiment, the method for preparing polysiloxane isocyanate includes the following steps:

[0065] Prepare polysiloxane solutions, phosgene solutions, and diamine solutions containing active hydrogen, respectively, wherein the solvent in each solution can be the aforementioned inert solvent;

[0066] A polysiloxane solution containing active hydrogen is mixed with a phosgene solution at a temperature of 0–70°C. A diamine solution is then added to the mixture for a cold phosgene reaction to generate intermediates such as carbamoyl chloride and amine hydrochloride, which are yellowish paste-like substances. The reaction time is 0.5–3 hours.

[0067] The temperature of the above mixture is adjusted to 80-220℃ for thermophotochemical reaction. The reaction is carried out for 1-2 hours until the slurry substance is completely decomposed and the reactant becomes a transparent brown liquid.

[0068] In one embodiment, a small amount of phosgene is introduced into the system during the thermophosgene reaction stage.

[0069] In one embodiment, the reaction solution obtained after the phosgenation reaction is completed is purged with nitrogen or methane at 120°C for several hours to remove phosgene byproducts such as HCl and unreacted residual phosgene. After that, the reaction solution is transferred to a vacuum distillation system for purification and removal of inert solvent to obtain the polysiloxane isocyanate product.

[0070] In one embodiment, the mass concentration of the polysiloxane solution containing active hydrogen can be 10-20%, for example 12%, 15%, or 18%.

[0071] In one embodiment, the mass concentration of the phosgene solution can be 15-25%, for example 16%, 17%, 18%, 19%, 20%, or 22%. Furthermore, the temperature of the phosgene solution is maintained below 0°C before the reaction.

[0072] In one embodiment, the mass concentration of the diamine solution can be 10-20%, more preferably 16-19%, for example 13%, 14%, 15%, 17%, or 18%.

[0073] One embodiment of the present invention provides a two-component room temperature vulcanizing silicone rubber composition, comprising component A and component B, wherein component A comprises a hydroxyl-containing polysiloxane and component B comprises the aforementioned polysiloxane isocyanate.

[0074] In one embodiment, the mass ratio of component A to component B can be 1:0.1 to 1:10, and more preferably 1:0.5 to 1:5.

[0075] In one embodiment, the hydroxyl-containing polysiloxane includes α,ω-dihydroxypolydimethylsiloxane.

[0076] In one embodiment, at 25°C, the viscosity (dynamic viscosity) of the hydroxyl-containing polysiloxane is 2–330,000 mPa·s, further can be 50–100,000 mPa·s, and even further can be 700–20,000 mPa·s, for example 150 mPa·s, 500 mPa·s, 750 mPa·s, 1500 mPa·s, 5000 mPa·s, 10000 mPa·s, 50000 mPa·s, and 80000 mPa·s.

[0077] In one embodiment, the hydroxyl-containing polysiloxane can be a mixture of multiple polysiloxanes (e.g., silicone oil) having the same structure but different viscosities.

[0078] In one embodiment, component A comprises 20 to 70 parts by weight (e.g., 30 to 65 parts by weight) of hydroxyl-containing polysiloxane, and component B comprises 10 to 150 parts by weight (e.g., 30 to 125 parts by weight or 30 to 100 parts by weight) of polysiloxane isocyanate.

[0079] In one embodiment, component A comprises 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, 60 parts by weight, or 67 parts by weight of hydroxyl-containing polysiloxane, and component B comprises 40 parts by weight, 50 parts by weight, 60 parts by weight, 70 parts by weight, 80 parts by weight, 90 parts by weight, 100 parts by weight, 110 parts by weight, or 120 parts by weight of polysiloxane isocyanate.

[0080] In one embodiment, component A includes a hydroxyl-containing polysiloxane and a catalyst; further, component A includes a hydroxyl-containing polysiloxane, a silicone resin, a catalyst, a filler, and an additive.

[0081] In one embodiment, the additive may be one or more of a foaming agent, a crosslinking agent, a silane coupling agent, and polydimethylsiloxane (dynamic viscosity of 2-300,000 mPa·s). Further, the foaming agent may include one or more of water, carbon dioxide, nitrogen, sodium bicarbonate, 141B, LBA, alkanolamine salts (such as CFA 8), and dichloromethane.

[0082] In one embodiment, component A comprises 20 to 70 parts by weight of a hydroxyl-containing polysiloxane, 0 to 25 parts by weight of a filler, and 0.2 to 7 parts by weight of a catalyst.

[0083] In one embodiment, component A includes 20 to 70 parts by weight (e.g., 30 to 50 parts by weight) of hydroxyl-containing polysiloxane, 5 to 45 parts by weight of silicone resin (e.g., 10 to 40 parts by weight), 0 to 25 parts by weight of filler (e.g., 1 to 20 parts by weight), 0.2 to 7 parts by weight of catalyst (e.g., 0.7 to 4.5 parts by weight), and 0 to 20 parts by weight of additive (e.g., 1 to 18 parts by weight).

[0084] In one embodiment, the catalyst includes an amine catalyst and / or an organometallic catalyst. The content of the amine catalyst in component A can be 0.1 to 5 parts by mass, more preferably 0.5 to 3 parts by mass; the content of the organometallic catalyst in component A can be 0.1 to 2 parts by mass, more preferably 0.2 to 1.5 parts by mass.

[0085] In one embodiment, the silicone resin includes one or more of methylphenyl silicone resin, methyl silicone resin, phenylmethyl silicone resin, epoxy-modified silicone resin, benzyl transparent silicone resin, methyl transparent silicone resin, mica-bonded silicone resin, polymethyl silicone resin, amino silicone resin, fluorosilicone resin, silicone-epoxy resin, silicone polyester resin, solvent-resistant silicone resin, methyl MQ silicone resin, and vinyl MQ silicone resin. Further, the silicone resin includes one or more of methylphenyl silicone resin, phenylmethyl silicone resin, benzyl transparent silicone resin, methyl MQ silicone resin, and vinyl MQ silicone resin.

[0086] In one embodiment, the filler includes one or more of the following: nano-calcium carbonate, fumed silica, silica powder, carbon black, aluminum hydroxide, alumina, zinc oxide, cerium oxide, silicon carbide, boron nitride, aluminum nitride, hollow glass microspheres, and hollow silica.

[0087] In one embodiment, the amine catalyst includes one or more of N,N,N',N”,N”-pentamethyldiethylenetriamine, N,N,N',N”,N”-pentamethyldipropylenetriamine, bis(2-dimethylaminoethyl) ether, 2,4,6-tris(dimethylaminomethyl)phenol, N-methylmorpholine, N-ethylmorpholine, 2,2-bismorpholinodiethyl ether, N-methylimidazolium, 1,2-dimethylimidazolium, diazabicyclo, 1,4-dimethylpiperazine, N,N,N-trimethylaminoethylpiperazine, tris(dimethylaminopropyl)amine, 1,3,5-tris(dimethylaminopropyl)-1,3,5-hexahydrotriazine, N,N-dimethylcyclohexylamine, and N,N-dimethylbenzylamine.

[0088] In one embodiment, the organometallic catalyst includes one or more of the following: dibutyltin disilicate, stannous octanoate, dibutyltin diacetate, di(dodecyl sulfide)dibutyltin, dioctyltin mercaptan catalyst, potassium isooctanoate, di(dodecyl sulfide)dibutyltin, potassium acetate, etc.

[0089] In one embodiment, hydroxyl-containing polydimethylsiloxane, silicone resin, and filler are thoroughly mixed and kept at 100–120°C (e.g., 105°C, 110°C, 115°C) for 1–2 hours (e.g., 1.5 hours); then cooled to below 40°C (e.g., 35°C), optional additives are added, and after mixing thoroughly, a catalyst is added.

[0090] In one embodiment, components A and B can be packaged in corresponding two-component A and B tubing and stored at room temperature.

[0091] One embodiment of the present invention provides the application of the above-mentioned polysiloxane isocyanate in the preparation of silicone rubber.

[0092] In one embodiment, the silicone rubber may be one or more of silicone adhesives, foamed silicone rubber, and silicone rubber elastomers.

[0093] The polysiloxane isocyanate of one embodiment of the present invention contains both a Si-O structure and an isocyanate structure, so that it has both the extensibility and viscoelasticity of polysiloxane and the reactivity of isocyanate.

[0094] This invention discloses a polysiloxane isocyanate for the preparation of (room temperature) vulcanized silicone rubber, which can improve the adhesive strength, tear resistance, and tensile strength of silicone rubber. Furthermore, the polysiloxane isocyanate containing a benzene ring can replace phenylene and phenyl ether silicone rubber, giving the silicone rubber excellent high-temperature resistance.

[0095] The polysiloxane isocyanate of one embodiment of the present invention can be used in the preparation of silicone rubber. In addition to being used as foamed silicone rubber, it can also be used as an adhesive, elastomer, etc., so that the new material has the advantages of both organosilicon materials and polyurethane materials, and improves the disadvantage of poor mechanical properties of organosilicon materials.

[0096] The polysiloxane isocyanate of one embodiment of the present invention can be used to prepare foamed silicone rubber that can be applied in the field of power battery potting.

[0097] This invention discloses a polysiloxane isocyanate that is well miscible with the polysiloxane in component A without the aid of other additives, solving the problem of incompatibility between polysiloxane and isocyanate. Furthermore, it only requires the addition of a traditional blowing agent and can achieve silicone foaming using existing polyurethane foaming technology. This effectively solves the technical problem of poor processability of silicone foam materials, as well as the problem of uncontrollable foaming degree and speed. It also solves the problems of cell fusion and escape during the silicone foaming process, enabling the application of polyurethane foaming technology to silicone foaming and overcoming the limitation of silicone foaming due to equipment incompatibility. This foamed silicone material exhibits excellent comprehensive mechanical properties, with uniform and fine pores and good elasticity. Compared to commercially available silicone foams using hydrogen as a blowing agent, it significantly reduces safety risks.

[0098] The polysiloxane isocyanate of one embodiment of the present invention has a Si-C or Si-OOCNH structure near the end that is more stable than the Si-O structure at the end of hydroxyl-terminated polysiloxanes. The C-OOCNH structure formed by the product after the reaction is more robust, overcoming the disadvantages of hydroxyl-terminated polysiloxanes such as instability, easy cross-linking, and easy breakage of molecular chain ends. When used in the preparation of silicone rubber, it can make up for the poor mechanical strength of silicone adhesives. Moreover, different types of end-capping groups can be selected according to the needs of downstream materials, satisfying the needs of different customers.

[0099] The polysiloxane isocyanate / two-component room temperature vulcanizing silicone rubber composition of one embodiment of the present invention can be used to prepare silicone rubber, and increases the processability of silicone rubber and improves the disadvantage of poor mechanical properties of silicone rubber; in addition, the polysiloxane isocyanate containing benzene rings can give silicone rubber the advantage of high temperature resistance.

[0100] The two-component room temperature vulcanizing silicone rubber of one embodiment of the present invention has good adhesion, tear resistance and tensile strength because the C-OOCNH and NCO groups in its molecular structure can form van der Waals forces and chemical bonds with the substrate.

[0101] The two-component room temperature vulcanizing silicone rubber of one embodiment of the present invention has excellent properties such as easy processing, high temperature resistance, weather resistance, and high mechanical strength.

[0102] The preparation of silicone rubber according to one embodiment of the present invention will be further described below with reference to the embodiments. The raw materials, equipment used, and testing methods involved in each embodiment are as follows.

[0103] raw material

[0104]

[0105] equipment

[0106] Instrument Name model Manufacturer Double planetary stirred tank ZYMC Shenzhen Zhongyi Technology Co., Ltd. Universal testing machine CMT4202 Zhuhai Sansi Zongheng Technology Co., Ltd. FF Foam hardness tester LX-C Yangzhou Sais Testing Equipment Co., Ltd. Fourier transform infrared spectrometer Tracer-100 Shimadzu Laboratory Instruments Co., Ltd. Scanning electron microscope JSM-6701F Nippon Electronics Co., Ltd.

[0107] Test methods

[0108] 1. Tensile strength and elongation at break test

[0109] Tensile strength and elongation at break were tested using a CMT4202 universal testing machine. The silicone rubber product was conditioned in a standard environment for more than 16 hours at a temperature of 23℃±2℃ and a relative humidity of 50℃±5%. The specimen thickness was 2mm, and it was a dumbbell-shaped specimen. The sample preparation and testing were carried out in accordance with the national standard GB / T6344-2008.

[0110] 2. Hardness test

[0111] The hardness of silicone rubber materials was tested according to the industry standard HG / T2489-2007 "Test Method for Hardness of Microporous Materials for Footwear". The instrument used was a Shore A foam hardness tester of model LX-C. The sample thickness was 10±0.5mm. For samples with a thickness of less than 10mm, two samples could be stacked together for testing, but the contact surface must be smooth and flat.

[0112] 3. Shear strength test

[0113] Shear strength was tested using a CMT4202 universal testing machine. The fully cured test samples were conditioned in a standard environment for at least 16 hours at a temperature of 23℃±2℃ and a relative humidity of 50°±5%. Sample preparation and testing were performed according to the national standard GB / T 33334-2016.

[0114] 4. Density test

[0115] Samples were prepared and tested in accordance with the national standard GB / T 553. Based on Archimedes' law of buoyancy, the density of the sample was calculated by measuring the buoyancy force on the sample in air and liquids of known density (such as water).

[0116] 5. Infrared spectroscopy test

[0117] Infrared spectroscopy of the samples was performed using a Shimadzu Tracer-100 Fourier transform infrared spectrometer. The samples were liquids; a small amount of liquid was applied between two KBr crystal wafers, and the wafers were pressed together to expel air bubbles, forming a thin sample layer before infrared detection. The wavenumber range was 400–4000 cm⁻¹. -1 To determine the molecular structure.

[0118] 6. Bubble count test

[0119] The morphology of the gold-sprayed sample was observed using a JSM-6701F scanning electron microscope from Nippon Electronics Co., Ltd., at a magnification of 50x.

[0120] 7. Aging test

[0121] After aging the samples in a 250℃ oven for 500 hours, tensile strength, elongation at break, and shear strength were tested.

[0122] 8. Gel time

[0123] After mixing components A and B, the gel is brought into contact with a glass rod, and the time it takes to form 3 cm fibers is measured. This time is called the gel time (also known as the fiber-drawing time).

[0124] Example 1

[0125] Preparation of polysiloxane isocyanates

[0126] S1: Dissolve 200 parts by mass of a polysiloxane with eugenol-terminated ends (Formula (IV), viscosity 2000 mPa·s) in 800 parts by mass of chlorobenzene to prepare a 20% polysiloxane solution with eugenol-terminated ends; dissolve 350 parts by mass of phosgene in 1900 parts by mass of chlorobenzene to prepare a 15.56% phosgene solution; dissolve 200 parts by mass of MDA in 1200 parts by mass of chlorobenzene to prepare a 14.29% chlorobenzene solution of MDA.

[0127] S2: In reactor R-1, a polysiloxane solution with eugenol end caps is mixed with a phosgene solution, and then mixed with a chlorobenzene solution of MDA. The mixture is subjected to a cold phosgene reaction at 50°C for 2 hours to generate a slurry-like reaction material.

[0128] S3: Transfer the above reaction solution from reactor R-1 to reactor R-2, introduce a small amount of phosgene, slowly raise the temperature to 210°C, maintain this temperature for 1 hour to carry out the thermo-phosgene reaction until the slurry substance is completely decomposed and the reactant becomes a transparent brown liquid.

[0129] S4: The solution obtained in step S3 is purified and chlorobenzene is removed to obtain polysiloxane isocyanate.

[0130] The obtained polysiloxane isocyanate was subjected to Fourier transform infrared (FTIR) spectroscopy, with the 3500 cm⁻¹ value being... -1 The characteristic peak at 1500 cm⁻¹ corresponds to the -OH stretching peak on the eugenol-terminated polysiloxane benzene ring. -1 The characteristic peaks at [location] correspond to the stretching vibration peaks of the benzene ring, and both characteristic peaks disappear. The characteristic peaks of MDA (4,4'-diaminodiphenylmethane) appear in the FTIR spectrum at 1289 cm⁻¹. -1 and 3415cm -1 The peak at 3415 cm⁻¹, its NH stretching vibration absorption peak is located at 3415 cm⁻¹. -1 At this location, its CN stretching vibration absorption peak is located at 1289 cm⁻¹. -1 At this point, both characteristic peaks disappear. And at a wavenumber of 2244 cm⁻¹... -1 A strong absorption peak for the isocyanate group (-N=C=O) appears at 1728 cm⁻¹. -1 The absorption peak of the C=O stretching vibration of the carbamate appears at a wavenumber of 2950 cm⁻¹. -1 The weak absorption peak at that point corresponds to the CH stretching vibration absorption peak of urethane, and these functional groups are the main functional groups in polysiloxane isocyanates.

[0131] The obtained polysiloxane isocyanate was subjected to nuclear magnetic resonance (NMR) testing. The spectrum showed that the -OH atomic absorption peak of the phenolic hydroxyl group at a chemical shift of 5.5 ppm had disappeared, indicating that the -OH had completely participated in the reaction, proving that the eugenol-terminated polysiloxane reacted completely with MDA.

[0132] Preparation of silicone rubber materials

[0133] 220g of α,ω-dihydroxypolydimethylsiloxane (viscosity 1500mPa·s), 430g of α,ω-dihydroxypolydimethylsiloxane (viscosity 5000mPa·s), 150g of MQ silicone resin, and 153g of nano-calcium carbonate were added to a 2L reactor and thoroughly mixed. The mixture was kept at 120℃ for 1 hour under vacuum. After that, the temperature was lowered to below 35℃. After thorough mixing, 5g of pentamethyldiethylenetriamine (an amine catalyst) and 2g of dibutyltin dilaurate (an organometallic catalyst) were added and stirred at low speed under vacuum for 10 minutes. Then, 40g of water was added and stirred at low speed for 10 minutes. After thorough mixing, component A was obtained.

[0134] The above-mentioned component A and component B polysiloxane isocyanate were mixed and cured at a mass ratio of 1:1.1 at 25°C and 50% humidity to obtain silicone rubber foam material.

[0135] Example 2

[0136] Preparation of polysiloxane isocyanates

[0137] S1: Dissolve 150 parts by mass of a polysiloxane (formula (V) structure, viscosity 5000 mPa·s) with allylphenol-terminated in 850 parts by mass of o-dichlorobenzene to prepare a 15% polysiloxane solution with allylphenol-terminated in 15% polysiloxane solution; dissolve 400 parts by mass of phosgene in 1800 parts by mass of o-dichlorobenzene to prepare an 18.18% phosgene solution; dissolve 300 parts by mass of TDA in 1100 parts by mass of o-dichlorobenzene to prepare a 21.43% TDA o-dichlorobenzene solution.

[0138] S2: In reactor R-1, a polysiloxane solution with allylphenol end caps is mixed with a phosgene solution, and then mixed with a TDA o-dichlorobenzene solution. The mixture is subjected to a cold phosgene reaction at 70°C for 1 hour to generate a slurry-like reaction material.

[0139] S3: Transfer the above reaction solution from reactor R-1 to reactor R-2, introduce a small amount of phosgene, slowly raise the temperature to 90°C, maintain this temperature for 2 hours to carry out the thermo-phosgene reaction until the slurry substance is completely decomposed and the reactant becomes a transparent brown liquid.

[0140] S4: The solution obtained in step S3 is purified and o-dichlorobenzene is removed to obtain polysiloxane isocyanate.

[0141] The obtained polysiloxane isocyanate was subjected to Fourier transform infrared spectroscopy, in which the 3340 cm⁻¹ value was measured. -1 The characteristic peak at 1590 cm⁻¹ corresponds to the -OH stretching peak on the polysiloxane benzene ring capped with allylphenol. -1 The characteristic peak at [location] corresponds to the stretching vibration peak of the benzene ring, and both characteristic peaks disappear. The characteristic peak of TDA appears in the FTIR spectrum at 1207 cm⁻¹. -1 and 3328cm -1 The peak at 3328 cm⁻¹, its NH stretching vibration absorption peak is located at 3328 cm⁻¹. -1 At this location, its CN stretching vibration absorption peak is located at 1207 cm⁻¹. -1 At this point, both characteristic peaks disappear. And at a wavenumber of 2270 cm⁻¹... -1 A strong absorption peak for the isocyanate group (-N=C=O) appears at 1698 cm⁻¹. -1 The absorption peak of the C=O stretching vibration of the carbamate appears at a wavenumber of 2970 cm⁻¹. -1 The weak absorption peak at that point corresponds to the CH stretching vibration absorption peak of urethane, and these functional groups are the main functional groups in polysiloxane isocyanates.

[0142] The obtained polysiloxane isocyanate was subjected to nuclear magnetic resonance (NMR) testing. The spectrum showed that the -OH atomic absorption peak of the phenolic hydroxyl group at chemical shift = 3.5 ppm of the di-terminated allylphenol had disappeared, indicating that the -OH had completely participated in the reaction, proving that the allylphenol-terminated polysiloxane reacted completely with TDA.

[0143] Preparation of silicone rubber materials

[0144] 134g of α,ω-dihydroxypolydimethylsiloxane (viscosity 10000mPa·s), 380g of α,ω-dihydroxypolydimethylsiloxane (viscosity 1500mPa·s), 400g of T resin, and 80g of silica powder were added to a 2L reactor and mixed thoroughly. The mixture was then kept at 105℃ for 1.5h under vacuum. Afterward, the mixture was cooled to below 35℃. After thorough mixing, 6g of stannous octoate was added and the mixture was stirred at low speed for 10min to obtain component A.

[0145] The above-mentioned component A and component B polysiloxane isocyanate were mixed and cured at a mass ratio of 1:1.2 at 25°C and 50% humidity to obtain silicone rubber material.

[0146] Example 3

[0147] Preparation of polysiloxane isocyanates

[0148] S1: Dissolve 100 parts by mass of a hydroxyl-terminated polysiloxane (formula (VI) structure, viscosity 750 mPa·s) in 900 parts by mass of dichloromethane to prepare a 10% hydroxyl-terminated polysiloxane solution; dissolve 380 parts by mass of phosgene in 1820 parts by mass of dichloromethane to prepare a 17.27% phosgene solution; dissolve 360 ​​parts by mass of HDA in 1460 parts by mass of dichloromethane to prepare a 19.78% HDA dichloromethane solution.

[0149] S2: In reactor R-1, a polysiloxane solution with hydroxyl-terminated ends is mixed with a phosgene solution, and then mixed with an o-dichlorobenzene solution of HDA. The mixture is subjected to a cold phosgene reaction at 30°C for 3 hours to generate a slurry-like reaction material.

[0150] S3: Transfer the above reaction solution from reactor R-1 to reactor R-2, introduce a small amount of phosgene, slowly raise the temperature to 160°C, maintain this temperature for 1.5 hours to carry out the thermo-phosgene reaction until the slurry substance is completely decomposed and the reactant becomes a transparent brown liquid.

[0151] S4: The solution obtained in step S3 is purified and dechloromethane is removed to obtain polysiloxane isocyanate.

[0152] The obtained polysiloxane isocyanate was subjected to Fourier transform infrared spectroscopy (FTIR) at 3513 cm⁻¹.-1 The characteristic peak at 1491 cm⁻¹ corresponds to the -OH stretching peak on the hydroxyl-terminated polysiloxane benzene ring. -1 The characteristic peak at [location] corresponds to the stretching vibration peak of the benzene ring, and both characteristic peaks disappear. The characteristic peak of HDA appears in the FTIR spectrum at 3339 cm⁻¹. -1 The peak at 1284 cm⁻¹ is its NH stretching vibration absorption peak, while its CN stretching vibration absorption peak is located at 1284 cm⁻¹. -1 At this point, both characteristic peaks disappear. And at a wavenumber of 2234 cm⁻¹... -1 A strong absorption peak for the isocyanate group (-N=C=O) appears at 1718 cm⁻¹. -1 The absorption peak of the C=O stretching vibration of the carbamate appears at a wavenumber of 2935 cm⁻¹. -1 The weak absorption peak at that point corresponds to the CH stretching vibration absorption peak of urethane, and these functional groups are the main functional groups in polysiloxane isocyanates.

[0153] The obtained polysiloxane isocyanate was subjected to nuclear magnetic resonance (NMR) testing. The spectrum showed that the atomic absorption peak of -NH2 at chemical shift = 1.2 ppm of HDA had disappeared, indicating that -NH2 had completely participated in the reaction, proving that the hydroxyl-terminated polysiloxane reacted completely with HDA.

[0154] Preparation of silicone rubber materials

[0155] 400g of α,ω-dihydroxypolydimethylsiloxane (viscosity 750mPa·s), 290g of α,ω-dihydroxypolydimethylsiloxane (viscosity 20000mPa·s), 108g of polydimethylsiloxane (viscosity 1000mPa·s), and 188g of fumed silica were added to a 2L reactor and thoroughly mixed. The mixture was then kept at 110℃ for 1 hour under vacuum. Afterward, the temperature was lowered to below 35℃. After thorough mixing, 14g of di(dodecyl sulfide)dibutyltin was added, and the mixture was stirred at low speed under vacuum for 10 minutes to obtain component A.

[0156] Component A and component B, polysiloxane isocyanate, were mixed and cured at a mass ratio of 1:1.3 at 25°C and 50% humidity to obtain a silicone rubber material.

[0157] Comparative Example 1

[0158] 450g of α,ω-dihydroxypolydimethylsiloxane (viscosity 1500cp), 150g of polyether-modified polysiloxane 8580, and 100g of nano-calcium carbonate were added to a 2L reactor. After thorough mixing, the mixture was kept at 110℃ for 1 hour while being evacuated to below -0.01MPa. The reactor was then cooled to below 35℃. Next, 20g of silane coupling agent KH560 and 20g of silane coupling agent KH550 were added, and the mixture was stirred at low speed for 10 minutes while being evacuated to below -0.01MPa. After thorough mixing, 30g of foaming catalyst N,N,N',N”,N”-pentamethyldiethylenetriamine and 10g of dibutyltin dilaurate were added, and the mixture was stirred at low speed for 10 minutes while being evacuated to below -0.01MPa. Finally, 180g of chemical foaming agent CFA was added. 8. Stir at low speed for 10 minutes until the mixture is homogeneous, then vacuum to below -0.01 MPa to obtain component A.

[0159] The above-mentioned component A and component B polymeric isocyanate PM-200 were mixed and cured at a mass ratio of 1:0.5 to obtain silicone rubber foam material.

[0160] Comparative Example 2

[0161] 134g of α,ω-dihydroxypolydimethylsiloxane (viscosity 10000mPa·s), 380g of α,ω-dihydroxypolydimethylsiloxane (viscosity 1500mPa·s), 400g of T resin, and 80g of silica powder were added to a 2L reactor and mixed thoroughly. The mixture was then kept at 105℃ for 1.5h under vacuum. Afterward, the mixture was cooled to below 35℃. After thorough mixing, 6g of stannous octoate was added and the mixture was stirred at low speed for 10min to obtain component A.

[0162] 100g of polydimethylsiloxane (viscosity 1000mPa·s), 400g of T resin, and 80g of silica powder were added to a 2L reactor and mixed thoroughly. The mixture was then treated at 105℃ for 1.5h while being vacuumed and cooled to below 35℃. After thorough mixing, 15g of tetraethyl orthosilicate and 6g of methyltrimethoxysilane were added and the mixture was stirred at low speed under vacuum for 10min to obtain component B.

[0163] Component A and component B are mixed and cured at a mass ratio of 1:1.2 to obtain silicone rubber material.

[0164] Comparative Example 3

[0165] 400g of α,ω-dihydroxypolydimethylsiloxane (viscosity 750mPa·s), 290g of α,ω-dihydroxypolydimethylsiloxane (viscosity 20000mPa·s), 108g of polydimethylsiloxane (viscosity 1000mPa·s), and 188g of fumed silica were added to a 2L reactor and thoroughly mixed. The mixture was then kept at 110℃ for 1 hour under vacuum. Afterward, the temperature was lowered to below 35℃. After thorough mixing, 14g of di(dodecyl sulfide)dibutyltin was added, and the mixture was stirred at low speed under vacuum for 10 minutes to obtain component A.

[0166] 108g of polydimethylsiloxane (viscosity 1000cp), 188g of fumed silica, and 2.75g of vinyltrimethoxysilane were added to a 2L reactor and mixed thoroughly. The mixture was kept at 100-120℃ for 1 hour under vacuum. After that, the mixture was cooled to below 35℃. After thorough mixing, 2g of silane coupling agent KH550 and 4g of silane coupling agent KH560 were added, and the mixture was stirred at low speed under vacuum for 10 minutes to obtain component B.

[0167] The above-mentioned components A and B are mixed and cured in a mass ratio of 2:1 to obtain silicone rubber material.

[0168] The silicone rubber foam materials prepared in Example 1 and Comparative Example 1 were tested for gel time, tensile strength, elongation at break, shear strength, hardness, density, and number of cells according to the aforementioned method. The results are shown in Table 1.

[0169] Table 1

[0170] project Example 1 Comparative Example 1 Gel time (min) 20 10 Tensile strength (MPa) 4.5 2.2 Elongation at break (%) 120 145 Shear strength (MPa) 3.0 2.1 Hardness (Shore A) 45 32 <![CDATA[Density (g / cm 3 )]]> 0.47 0.45 <![CDATA[Cell count (cells / square cm 2 )]]> 575 240 Bubble Uniform and fine foam pores Uneven, irregular, with large pores

[0171] As can be clearly seen from Table 1, compared with Comparative Example 1, which uses polymeric isocyanate PM-200 as component B, the silicone PU foam material prepared in Example 1 has better mechanical strength and a more uniform and delicate cell structure, which solves the problem of difficult silicone foaming and reduces the dependence on specialized foaming equipment, thus facilitating industrialization.

[0172] The silicone rubber material of Example 2 and the condensation-type silicone rubber of Comparative Example 2 were tested according to the aforementioned method, and the results are shown in Table 2.

[0173] Table 2

[0174]

[0175] As can be clearly seen from Table 2, the polysiloxane isocyanate with benzene rings in Example 2 provides the silicone rubber with better adhesion and high-temperature resistance. Specifically, components A and B in Comparative Example 2 are basically the same, and are also the same as component A in Example 2. Combining the results in Table 2, it can be seen that the introduction of component B in Example 2 significantly improves the overall performance of the material.

[0176] Table 3 lists the performance test data of the silicone rubber of Example 3 and the de-alcoholized silicone adhesive of Comparative Example 3.

[0177] Table 3

[0178] project Example 3 Comparative Example 3 Gel time (min) 10 10 Tensile strength (MPa) 4.0 1.9 Elongation at break (%) 350 248 Shear strength (MPa) 2.3 1.2 Hardness (Shore A) 42 35 <![CDATA[Density (g / cm 3 )]]> 1.08 1.07

[0179] As can be seen from the data in Table 3, the silicone adhesive prepared by the polysiloxane isocyanate of Example 3 of this invention has higher tensile strength and shear strength. When preparing silicone adhesive materials, excellent bonding performance is improved without the use of silane coupling agents. It has broad application prospects and is conducive to industrialization.

[0180] Unless otherwise specified, the terms used in this invention have the meanings commonly understood by those skilled in the art.

[0181] The embodiments described in this invention are for illustrative purposes only and are not intended to limit the scope of protection of this invention. Those skilled in the art can make various other substitutions, changes and improvements within the scope of this invention. Therefore, this invention is not limited to the above embodiments, but is only defined by the claims.

Claims

1. A silicone rubber composition comprising component A and component B, wherein component A comprises a hydroxyl-containing polysiloxane, and component B comprises a polysiloxane isocyanate; wherein, The polysiloxane isocyanate has the following structure: R1 and R2 are independently selected from hydrogen atoms, halogen atoms, alkyl groups containing 1 to 18 carbon atoms, alkoxy groups containing 1 to 18 carbon atoms, or aryl groups containing 6 to 12 carbon atoms; X is selected from alkylene containing 1 to 18 carbon atoms, cycloalkylene containing 4 to 8 carbon atoms, or substituted or unsubstituted arylene containing 6 to 18 carbon atoms, wherein the substituent of the substituted arylene is selected from one or more of phenyl, halogen atom, methyl, methoxy, ethyl, and ethoxy. Y is absent or selected from alkylene groups containing 1 to 18 carbon atoms, substituted or unsubstituted aryl groups containing 6 to 18 carbon atoms, wherein the substituent of the substituted aryl group is selected from one or more of phenyl, halogen, methoxy, ethyl, and allyl.

2. The composition according to claim 1, wherein, The polysiloxane isocyanate is prepared by reacting a polysiloxane containing active hydrogen with phosgene and a diamine. The polysiloxane containing active hydrogen has the following structure: R1 and R2 are independently selected from hydrogen atoms, halogen atoms, alkyl groups containing 1 to 18 carbon atoms, alkoxy groups containing 1 to 18 carbon atoms, or aryl groups containing 6 to 12 carbon atoms; Y is absent or selected from alkylene groups containing 1 to 18 carbon atoms, substituted or unsubstituted aryl groups containing 6 to 18 carbon atoms, wherein the substituent of the substituted aryl group is selected from one or more of phenyl, halogen, methoxy, ethyl, and allyl.

3. The composition according to claim 2, wherein, In the structure of the polysiloxane isocyanate, X is selected from phenylene, methylphenylene, hexylene, -phenylene-CH2-phenylene-, -cyclohexylene-CH2-cyclohexylene-, 1,3,3-trimethylcyclohexylmethylene; or, The polysiloxane containing active hydrogen is prepared by an addition reaction between a phenolic compound containing double bonds and a polysiloxane containing silane-hydrogen bonds. The phenolic compound containing double bonds includes one or more of 4-vinylphenol, 4-allylphenol, 2-allylphenol, 3-allylphenol, eugenol, 4-allyl-2,6-dimethoxyphenol, and 4-isopropenylphenol; and / or... The hydroxyl-containing polysiloxane includes α,ω-dihydroxypolydimethylsiloxane; and / or, The mass ratio of component A to component B is 0.2:1 to 1:15; and / or, n is selected from 20 to 180; and / or, Component A comprises 20 to 70 parts by weight of the hydroxyl-containing polysiloxane, and component B comprises 10 to 150 parts by weight of the polysiloxane isocyanate.

4. The composition according to claim 2, wherein, In the structure of the polysiloxane isocyanate or the polysiloxane containing active hydrogen, Y is absent or selected from the following structures: Wherein, Y1 and Y2 are each independently hydrogen, methoxy, or allyl, and R3 is -CH2-CH2-, -CH2-CH2-CH2-, or -CH(CH3)CH2-; and / or, The diamine comprises one or more of 4,4'-diaminodiphenylmethane, 5-amino-1,3,3-trimethylcyclohexylmethane, 4,4'-diaminodicyclohexylmethane, toluenediamine, and hexamethylenediamine; and / or The molar number of phosgene is 1.1 to 1.5 times the sum of the molar numbers of the diamine and the polysiloxane containing active hydrogen; and / or, Component A includes the hydroxyl-containing polysiloxane and catalyst, and optionally a silicone resin, filler, and additives; and / or, The polysiloxane containing active hydrogen includes one or more of eugenol-terminated polysiloxanes, 4-allylphenol-terminated polysiloxanes, and hydroxyl-terminated polysiloxanes; and / or, The viscosity of the polysiloxane containing active hydrogen is 2–330,000 mPa·s.

5. The composition according to claim 4, wherein, The catalyst includes amine catalysts and / or organometallic catalysts; and / or, Component A comprises 20-70 parts by weight of the hydroxyl-containing polysiloxane, 5-45 parts by weight of the silicone resin, 0-25 parts by weight of the filler, 0.2-7 parts by weight of the catalyst, and 0-20 parts by weight of the additives; and / or, The viscosity of the polysiloxane containing active hydrogen is 700–5000 mPa·s; and / or, The polysiloxane isocyanate is selected from one or more of the following structures:

6. A silicone rubber, obtained by means of the composition according to any one of claims 1 to 5.

7. A polysiloxane isocyanate having the following structure: R1 and R2 are independently selected from hydrogen atoms, halogen atoms, alkyl groups containing 1 to 18 carbon atoms, alkoxy groups containing 1 to 18 carbon atoms, or aryl groups containing 6 to 12 carbon atoms; X is selected from alkylene containing 1 to 18 carbon atoms, cycloalkylene containing 4 to 8 carbon atoms, or substituted or unsubstituted arylene containing 6 to 18 carbon atoms, wherein the substituent of the substituted arylene is selected from one or more of phenyl, halogen atom, methyl, methoxy, ethyl, and ethoxy. Y is absent or selected from alkylene groups containing 1 to 18 carbon atoms, substituted or unsubstituted aryl groups containing 6 to 18 carbon atoms, wherein the substituent of the substituted aryl group is selected from one or more of phenyl, halogen, methoxy, ethyl, and allyl.

8. The polysiloxane isocyanate according to claim 7 is prepared by reacting a polysiloxane containing active hydrogen with phosgene and a diamine; The polysiloxane containing active hydrogen has the following structure: R1 and R2 are independently selected from hydrogen atoms, halogen atoms, alkyl groups containing 1 to 18 carbon atoms, alkoxy groups containing 1 to 18 carbon atoms, or aryl groups containing 6 to 12 carbon atoms; Y is absent or selected from alkylene containing 1 to 18 carbon atoms, substituted or unsubstituted arylene containing 6 to 18 carbon atoms, wherein the substituent of the substituted arylene is selected from one or more of phenyl, halogen atom, methoxy, ethyl, and allyl. n is selected from 20 to 180.

9. A method for preparing the polysiloxane isocyanate according to claim 7 or 8, comprising reacting a polysiloxane containing active hydrogen with phosgene and a diamine to obtain the polysiloxane isocyanate.

10. The use of the polysiloxane isocyanate according to claim 7 or 8 in the preparation of silicone rubber.

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