Low-pressure-difference liquid storage bag silicone rubber

Abstract

The invention provides low-pressure-difference liquid storage bag silicone rubber and a preparation method thereof. The silicone rubber is prepared from methyl vinyl raw rubber (A), methyl vinyl raw rubber (B), reinforcing filler and a processing aid. Wherein the raw rubber (A) is end-side vinyl polysiloxane, and the content of vinyl is 0.08-0.16%; and the raw rubber (B) is side vinyl polysiloxane, and the vinyl content is 0.02-0.10%. And the reinforcing filler adopts fumed silica. The processing aid contains hydroxyl vinyl silicone oil, linear silicone oil containing hydrogen at the end side, an inhibitor, a platinum catalyst and the like. By compounding the end-side vinyl silicone rubber and the side vinyl silicone rubber, the crosslinking density and elasticity are balanced, the capsule pressure change value is reduced, and the dosing accuracy of the liquid storage capsule and the intracranial pressure stability are improved. The preparation method comprises the steps of internal mixing, batch charging, mold vulcanization and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to silicone rubber, in particular to silicone rubber used for producing liquid storage capsules. Background Art

[0002] The fluid reservoir is a common medical device in clinical medicine, also known as the Ommaya capsule. It usually includes a fluid reservoir and a drainage tube connected to it. The fluid reservoir is usually made of silicone and is used for multiple self-sealing punctures. It is mostly used for central nervous system chemotherapy administration and cerebrospinal fluid sampling.

[0003] The pressure differential of the reservoir includes internal pressure differential and external pressure differential. The internal pressure differential refers to the pressure difference between different areas inside the reservoir; the external pressure differential refers to the difference between the internal pressure of the reservoir and the external environment. The external pressure differential can be regulated by an infusion pump to drive the flow of liquid inside the reservoir, thereby controlling the cerebrospinal fluid drainage rate. The internal pressure differential is related to material deformation, etc. With regard to the internal pressure differential, a low pressure differential can allow the drug to be released slowly and evenly, avoiding ventricular collapse or intracranial tissue damage caused by excessive drainage. Maintaining a more stable intracranial pressure reduces the occurrence of low intracranial pressure syndromes such as headaches and nausea. Reduce nerve stimulation caused by sudden changes in spinal cavity pressure.

[0004] Existing technologies, including utility model patents with publication numbers CN219963456U, CN203874183U, and CN219941230U, improve the structure of the reservoir to achieve good resilience. However, these improvements often hinder the operation of the reservoir. The complex structural design can increase the difficulty of puncture, affect the doctor's operating experience, and even cause the reservoir to poorly adhere to the surrounding tissue, leading to the risk of displacement or leakage.

[0005] The prior invention patent application with publication number CN118027680A provides a wear-resistant silicone rubber, but its internal pressure difference performance still needs to be improved. It is necessary to develop a silicone rubber suitable for liquid storage capsules to solve the above problems. Summary of the Invention

[0006] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a silicone rubber suitable for a liquid storage capsule. The internal fluid of the liquid storage capsule made of this silicone rubber has a stable internal pressure difference during the flow process, so that the flow rate and rate of the output fluid are stable.

[0007] To achieve the above-mentioned object, the technical solution provided by the present invention includes, in a first aspect, a low-pressure-difference liquid storage capsule silicone rubber, the components of which include methyl vinyl rubber (A), methyl vinyl rubber (B), reinforcing filler, and processing aid; The methyl vinyl rubber (A) is a vinyl end polysiloxane with a relative molecular weight of 500,000 to 650,000 and a vinyl content of 0.08-0.16%. The methyl vinyl rubber (B) is a vinyl end polysiloxane with a relative molecular weight of 600,000 to 650,000 and a vinyl content of 0.02-0.10%.

[0008] As an optional embodiment, the processing aid includes but is not limited to functional additives involving at least one of the following.

[0009] A cross-linking agent used to promote cross-linking of rubber molecular chains to form a three-dimensional network structure, such as one or a combination of sulfur, dicumyl peroxide, benzoyl peroxide, ethidium tetrasulfide, zinc oxide, quinone dioxime, methyltriethoxysilane, etc.

[0010] By regulating the internal structure of the material using a structural control agent, such as one or a combination of fatty acid salts, stearic acid, ethyl palmitate, polyethylene glycol, liquid crystal polymers, epoxy soybean oil, etc.

[0011] Antioxidants that inhibit thermal oxidative aging of polymer materials, such as one or a combination of 2,6-di-tert-butyl-p-cresol, hindered phenol antioxidants, phosphite antioxidants, vitamin-based natural antioxidants, polymer phenols, etc.

[0012] Lubricants that reduce intermolecular friction during processing, such as one or a combination of paraffin wax, calcium stearate, polyethylene wax, polypropylene wax, montan wax, amide wax, low relative molecular weight polyalphaolefin, etc.

[0013] Inhibitors used to slow down the chemical reaction rate of materials, such as one or a combination of phthalic anhydride, maleic anhydride, p-benzoquinone, cyclohexanedicarboxylic anhydride, diphenyliodonium hexafluorophosphate, benzoyl chloride, etc.

[0014] A catalyst for accelerating the cross-linking reaction, such as one or a combination of triethanolamine, dibutyltin dilaurate, stannous chloride, aluminum isopropoxide, organic bismuth compounds, triphenylphosphine, etc.

[0015] Wear-resistant additives that improve the wear resistance of the surface of rubber products, such as one or a combination of silicon carbide, silicon dioxide, aluminum oxide, boron nitride, graphene, carbon nanotubes, etc.

[0016] And a release agent for preventing the molded product from sticking to the mold, such as one or a combination of magnesium stearate, organic silicon compounds, methyl branched silicone oil, polytetrafluoroethylene powder, carnauba wax, perfluoropolyether, etc.

[0017] The reinforcing filler is a component that forms a stress transfer network through physical / chemical combination of filler particles and silicone rubber molecular chains to resist external force deformation, including but not limited to at least one of fumed silica, carbon black, nano-calcium carbonate, nano-alumina, zinc oxide, titanium oxide and the like.

[0018] Furthermore, the low pressure difference liquid storage capsule silicone rubber comprises the following components by mass: 20-70 parts of methyl vinyl rubber (A); 30-80 parts of methyl vinyl rubber (B); and 40-50 parts of reinforcing filler.

[0019] Methyl vinyl rubber (A) refers to a polysiloxane whose main chain is formed by alternating silicon-oxygen bonds (Si-O), has vinyl end groups, and the silicon atoms of the side chains are connected to vinyl groups that give the polymer reactivity; methyl vinyl rubber (B) refers to a polysiloxane whose main chain is formed by alternating silicon-oxygen bonds, does not contain vinyl groups at the end groups, and except for a small amount of vinyl groups, the side groups are mainly or entirely methyl groups. Here, mainly methyl groups refer to hydrogen atoms that may also be connected to the Si atoms.

[0020] Furthermore, the processing aids include: a structuring control agent, 0.5-2 parts; a hydrogen-containing crosslinking agent, 0.85-0.90 parts; an inhibitor, 0.02-0.10 parts; and a platinum catalyst, 0.1-2 parts.

[0021] Here, hydrogen-containing crosslinking agents refer to compounds with active hydrogen (such as Si-H, NH, OH, etc.) in their molecular structure. They can promote the formation of crosslinking structures between material molecular chains through chemical reactions (such as addition, condensation, etc.), thereby improving the strength, heat resistance, solvent resistance and other properties of the material.

[0022] Furthermore, the processing aids include 5-10 parts of a wear-resistant additive and 0.1-2 parts of an internal release agent.

[0023] Furthermore, the reinforcing filler is fumed silica, and its specific surface area is not less than 300m 2 Here, fumed silica refers to a nanoscale inorganic material prepared by the chemical vapor deposition (CAV) method, usually using silicon tetrachloride as the main raw material, which is obtained by gas-phase hydrolysis reaction with hydrogen and oxygen at high temperature; it can also be purchased from commercial products.

[0024] Furthermore, the hydrogen-containing crosslinking agent is a linear silicone oil containing hydrogen at its end, with a hydrogen content of 0.75-1.25%, where hydrogen content refers to the percentage of hydrogen in the total weight of the silicone oil. The Si-H bonds can crosslink with vinyl-containing silicone oil or rubber through a platinum-catalyzed addition reaction, forming a three-dimensional network structure for rubber vulcanization.

[0025] Furthermore, the structuring control agent is a hydroxyl vinyl silicone oil with a hydroxyl content of 6.5% and a vinyl content of 7% by mass. The hydroxyl groups, under catalytic conditions, undergo a condensation reaction to form Si-O-Si bonds, which are used to vulcanize the silicone rubber and simultaneously adjust viscosity and thixotropy. The vinyl groups crosslink with the hydrogenated silicone oil through a platinum-catalyzed addition reaction to form an addition-type silicone rubber, which is used to enhance reactivity, crosslink density, and improve elasticity.

[0026] Furthermore, the internal release agent is zinc stearate.

[0027] Although the above silicone rubber can be prepared by conventional raw rubber mixing, additive mixing and molding, in order to make the present invention clearer and more detailed. In a second aspect, the present invention also provides a method for preparing silicone rubber having at least one of the above technical features, comprising the following steps: S1, adding methyl vinyl rubber A and methyl vinyl rubber B into an internal mixer and mixing them, and adding a structuring control agent during the mixing process; S2, after adding reinforcing fillers in batches into the internal mixer, adding hydrogen-containing cross-linking agent, inhibitor, platinum catalyst, wear-resistant additive and internal release agent into the internal mixer; S3, the mixed rubber is loaded into the liquid reservoir mold and vulcanized.

[0028] Furthermore, in said S1, the banburying temperature is 50-70°C, and after the initial mixing for 10-15 minutes, a structuring control agent is added; And / or, in S2, the mixing temperature is ≤80°C, the shear rate is 200-300 rpm, and the mixing time is 20-30 min; And / or, in S3, the molding temperature of the liquid storage capsule mold is 120-150° C., the pressure is 8-12 MPa, and the vulcanization time is 15-25 minutes.

[0029] This method first mixes the raw rubber at medium temperature for a period of time to achieve physical entanglement and compatibility of the molecular chains. Then, a structuring agent is added. Mixing the two rubbers in the molten state reduces the risk of phase separation and creates a homogeneous matrix for the subsequent dispersion of reinforcing fillers. Adding the structuring agent too early will preferentially react with the vinyl or silanol groups in the raw rubber, weakening its ability to control the filler-rubber interface. Delaying the addition of the structuring agent allows for more precise control of the interfacial energy during filler dispersion, improving reinforcement efficiency.

[0030] The advantages and beneficial effects of the present invention lie in its use of a composite system of vinyl-terminated polysiloxane and vinyl-pendent polysiloxane. The vinyl-terminated polysiloxane provides main chain crosslinking points, while the vinyl-pendent polysiloxane enhances molecular chain flexibility, balancing crosslink density and elasticity. By regulating the total vinyl content, brittleness caused by excessive crosslinking is avoided. Liquid reservoirs made with this silicone rubber exhibit significantly lower pressure fluctuations compared to existing silicone rubbers, improving the accuracy of liquid reservoir drug delivery and stabilizing intracranial pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a process flow chart for preparing the silicone rubber low pressure difference liquid storage capsule shown in the present invention; Figure 2 These are photos of the finished products of the low-pressure differential liquid storage capsules of the present invention (from bottom to top, respectively, Example 1 and Example 2). DETAILED DESCRIPTION

[0032] The following embodiments are further described in conjunction with the accompanying drawings and examples. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0033] Example 1 A low-pressure-difference liquid storage capsule silicone rubber comprises the following components in parts by weight: Methyl vinyl rubber (A) 60 servings Methyl vinyl rubber (B) 40 servings Reinforcing fillers 45 servings Structural control agent 1 serving Hydrogen-containing crosslinking agent 0.90 servings inhibitors 0.05 parts Platinum catalyst 0.3 parts Among them, the molecular weight of methyl vinyl raw rubber (A) is 600,000~650,000, and the vinyl content is 0.12%; the molecular weight of methyl vinyl raw rubber (B) is 600,000~650,000, and the vinyl content is 0.04%, and the reinforcing filler is fumed silica; the structuring control agent is hydroxy vinyl silicone oil with a hydroxyl content of 6.5% and a vinyl content of 7%; the hydrogen-containing crosslinking agent is a side hydrogen-containing linear silicone oil with a hydrogen content of 0.75%.

[0034] The preparation method of this silicone rubber is as follows: S1, adding methyl vinyl rubber A and methyl vinyl rubber B into an internal mixer, mixing at 70°C, and adding a structure control agent after preliminary mixing for 15 minutes; S2, after adding reinforcing fillers and processing aids in batches into the internal mixer, mixing at 80°C for 20 min and a shear rate of 200 rpm; S3, the mixed rubber is loaded into a liquid reservoir mold and compression-vulcanized at 150°C and 8 MPa for 15 minutes.

[0035] Example 2 A low-pressure-difference liquid storage capsule silicone rubber comprises the following components in parts by weight: Methyl vinyl rubber (A) 50 servings Methyl vinyl rubber (B) 50 servings Reinforcing fillers 40 servings Structural control agent 1 serving Hydrogen-containing crosslinking agent 0.85 servings inhibitors 0.05 parts Platinum catalyst 0.3 parts Wear-resistant additives 5 servings Among them, the molecular weight of methyl vinyl raw rubber (A) is 600,000~650,000, and the vinyl content is 0.12%; the molecular weight of methyl vinyl raw rubber (B) is 600,000~650,000, and the vinyl content is 0.04%, and the reinforcing filler is fumed silica; the structuring control agent is hydroxy vinyl silicone oil with a hydroxyl content of 6.5% and a vinyl content of 7%; the hydrogen-containing crosslinking agent is a side hydrogen-containing linear silicone oil with a hydrogen content of 1.15%.

[0036] S1, adding methyl vinyl rubber A and methyl vinyl rubber B into an internal mixer, mixing at 50°C, and adding a structure control agent after preliminary mixing for 10 minutes; S2, after adding reinforcing fillers and processing aids in batches into the internal mixer, mixing at 75 ° C for 20 min and a shear rate of 300 rpm; S3, the mixed rubber is loaded into a liquid reservoir mold and compression-vulcanized at 1350°C and 10 MPa for 20 minutes.

[0037] Example 3 A low-pressure-difference liquid storage capsule silicone rubber comprises the following components in parts by weight: Methyl vinyl rubber (A) 30 servings Methyl vinyl rubber (B) 70 servings Reinforcing fillers 40 servings Structural control agent 1 serving Hydrogen-containing crosslinking agent 0.85 servings inhibitors 0.05 parts Platinum catalyst 0.3 parts Internal release agent 0.3 parts Wear-resistant additives 10 servings Among them, the molecular weight of methyl vinyl raw rubber (A) is 500,000~600,000, and the vinyl content is 0.14%; the molecular weight of methyl vinyl raw rubber (B) is 600,000~650,000, and the vinyl content is 0.10%, and the reinforcing filler is fumed silica; the structuring control agent is hydroxy vinyl silicone oil with a hydroxyl content of 6.5% and a vinyl content of 7%; the hydrogen-containing crosslinking agent is a side hydrogen-containing linear silicone oil with a hydrogen content of 1.0%, and the internal release agent is zinc stearate.

[0038] S1, adding methyl vinyl rubber A and methyl vinyl rubber B into an internal mixer, mixing at 60°C, and adding a structure control agent after preliminary mixing for 15 minutes; S2, after adding reinforcing fillers and processing aids in batches into the internal mixer, mixing at 70°C for 30 min and a shear rate of 300 rpm; S3, the mixed rubber is loaded into a liquid reservoir mold and compression-vulcanized at 120°C and 12 MPa for 15 minutes.

[0039] Example 4 A low-pressure-difference liquid storage capsule silicone rubber comprises the following components in parts by weight: Methyl vinyl rubber (A) 20 servings Methyl vinyl rubber (B) 80 servings Reinforcing fillers 50 servings Structural control agent 0.5 serving Hydrogen-containing crosslinking agent 0.90 servings inhibitors 0.10 parts Platinum catalyst 0.1 part Internal release agent 2 servings Among them, the molecular weight of methyl vinyl raw rubber (A) is 500,000~550,000, and the vinyl content is 0.08%; the molecular weight of methyl vinyl raw rubber (B) is 600,000~650,000, and the vinyl content is 0.02%, and the reinforcing filler is fumed silica; the structuring control agent is hydroxy vinyl silicone oil with a hydroxyl content of 6.5% and a vinyl content of 7%; the hydrogen-containing crosslinking agent is a side hydrogen-containing linear silicone oil with a hydrogen content of 1.20%; and the internal release agent is magnesium stearate.

[0040] S1, adding methyl vinyl rubber A and methyl vinyl rubber B into an internal mixer, mixing at 50°C, and adding a structure control agent after preliminary mixing for 10 minutes; S2, after adding reinforcing fillers and processing aids in batches into the internal mixer, mix at 80°C for 20-30 minutes and a shear rate of 270 rpm; S3, the mixed rubber is loaded into a liquid reservoir mold and compression-vulcanized at 140°C and 8 MPa for 20 minutes.

[0041] Example 5 A low-pressure-difference liquid storage capsule silicone rubber comprises the following components in parts by weight: Methyl vinyl rubber (A) 70 servings Methyl vinyl rubber (B) 40 servings Reinforcing fillers 45 servings Structural control agent 2 servings Hydrogen-containing crosslinking agent 0.85 servings inhibitors 0.02 parts Platinum catalyst 2 servings Internal release agent 0.1 part Among them, the molecular weight of methyl vinyl raw rubber (A) is 500,000~600,000, and the vinyl content is 0.16%; the molecular weight of methyl vinyl raw rubber (B) is 600,000~650,000, and the vinyl content is 0.08%, and the reinforcing filler is fumed silica; the structuring control agent is hydroxy vinyl silicone oil with a hydroxyl content of 6.5% and a vinyl content of 7%; the hydrogen-containing crosslinking agent is a side hydrogen-containing linear silicone oil with a hydrogen content of 1.25%, and the internal release agent is calcium stearate.

[0042] S1, adding methyl vinyl rubber A and methyl vinyl rubber B into an internal mixer, mixing at 60°C, and adding a structure control agent after preliminary mixing for 15 minutes; S2, after adding reinforcing fillers and processing aids in batches into the internal mixer, mixing at 70°C for 30 min and a shear rate of 300 rpm; S3, the mixed rubber is loaded into a liquid reservoir mold and compression-vulcanized at 120°C and 8 MPa for 15 minutes.

[0043] Comparative Example 1 A liquid storage capsule silicone rubber, comprising the following components in parts by weight: Methyl vinyl rubber (A) 100 copies Reinforcing fillers 40 servings Structural control agent 1 serving Hydrogen-containing crosslinking agent 0.90 servings inhibitors 0.05 parts Platinum catalyst 0.3 parts Among them, the molecular weight of methyl vinyl raw rubber (A) is 590,000~610,000, and the vinyl content is 0.12%; the strong filler is fumed silica; the structuring control agent is hydroxy vinyl silicone oil with a hydroxyl content of 6.5% and a vinyl content of 7%; the hydrogen-containing crosslinking agent is a terminal hydrogen-containing linear silicone oil with a vinyl content of 1.25%.

[0044] S1, adding methyl vinyl rubber A into an internal mixer, mixing at 50°C, initially mixing for 15 minutes, and then adding a structuring control agent; S2, after adding reinforcing fillers and processing aids in batches into the internal mixer, mixing at 80°C for 20 min and a shear rate of 200 rpm; S3, the mixed rubber is loaded into a liquid reservoir mold and compression-vulcanized at 120°C and 12 MPa for 25 minutes.

[0045] Comparative Example 2 The invention discloses a liquid storage capsule, which is made of commercially available liquid storage capsule silicone rubber.

[0046] The silicone rubber obtained in the above examples and comparative examples was subjected to performance testing, and the test results are shown in the following table. Appearance was determined visually; hardness was determined according to GB / T 531.1: Rubber, vulcanized or thermoplastic - Indentation Hardness Test Method. A 6 mm thick sheet was prepared and a durometer was pressed vertically into the sample surface until pressure reached a stable value. Tensile strength was determined according to GB / T 528: Rubber, vulcanized or thermoplastic - Determination of Tensile Stress-Strain Properties. The sample was clamped at both ends in a dumbbell-type testing machine and stretched at a speed of 500 mm / min until it broke. The maximum tensile force was recorded to calculate the tensile strength. Elongation at break was determined according to GB / T 528: The percentage change in length between a 25 mm long sample and the original marking after stretching to break was measured. Tear strength was determined according to GB / T 529, Trouser-Tear Method. The sample was clamped at both ends in a universal testing machine and stretched at a speed of 500 mm / min until it completely tore. The maximum tear force was recorded. The liquid storage capsule made of silicone rubber in each embodiment and comparative example was connected to one end of a silicone tube measuring 8.8 mm * 11.5 mm * 75 mm (inner diameter * outer diameter * length), and then secondary vulcanized in an oven at 200°C for 4 h. The liquid storage capsule connected to the silicone tube was taken out, and an air pump with an air pressure measurement function was used to inflate the liquid storage capsule with 120 mL of air. The air pump was then adjusted to slowly deflate at a rate of 2 mL / s, and the pressure change from the maximum to the minimum value of the capsule pressure was recorded. Test items Appearance Hardness / shoreA Tensile strength / Mpa Elongation at break / % Tear strength / KN / m Pressure difference change / Kpa Example 1 translucent 35 9.8 622 34.2 5.2 Example 2 Foggy translucent 32 10.2 701 42.5 4.1 Example 3 Foggy translucent 37 11.5 687 48.5 3.8 Example 4 Foggy translucent 33 10.8 653 45.2 5.1 Example 5 Foggy translucent 35 9.5 627 44.8 4.7 Comparative Example 1 translucent 40 9.1 660 30.7 17 Comparative Example 2 translucent 36 10.5 860 41.4 16 The performance test results above show that the bladder pressure variation values ​​of the examples ranged from 3.8 to 5.2 kPa, significantly lower than those of the comparative examples. This demonstrates that the composite system of end-vinyl polysiloxane (A) and end-vinyl polysiloxane (B) modulates crosslink density and molecular chain flexibility. Using only raw rubber A in the comparative example results in an excessively high crosslink density, increased material rigidity but decreased elasticity, poor deformation recovery, and high bladder pressure variation.

[0047] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A low pressure difference liquid storage capsule silicone rubber, characterized in that: The invention comprises the following components: methyl vinyl rubber (A), which is a vinyl end polysiloxane with a relative molecular weight of 500,000-650,000 and a vinyl content of 0.08-0.16%; methyl vinyl rubber (B), which is a vinyl end polysiloxane with a relative molecular weight of 600,000-650,000 and a vinyl content of 0.02-0.10%; reinforcing filler; and processing aids.

2. The liquid reservoir silicone rubber according to claim 1, characterized in that: The low pressure difference liquid storage capsule silicone rubber comprises the following components by weight: 20-70 parts of methyl vinyl rubber (A); 30-80 parts of methyl vinyl rubber (B); and 40-50 parts of reinforcing filler.

3. The liquid reservoir silicone rubber according to claim 2, characterized in that: The processing aids include: a structuring control agent, 0.5-2 parts; a hydrogen-containing cross-linking agent, 0.85-0.90 parts; an inhibitor, 0.02-0.10 parts; and a platinum catalyst, 0.1-2 parts.

4. The liquid reservoir silicone rubber according to claim 3, characterized in that: The processing aids also include 5-10 parts of a wear-resistant additive and 0.1-2 parts of an internal release agent.

5. The liquid reservoir silicone rubber according to any one of claims 1 to 4, characterized in that: The reinforcing filler is fumed silica, and its specific surface area is not less than 300m 2 / g.

6. The liquid reservoir silicone rubber according to claim 3 or 4, characterized in that: The hydrogen-containing cross-linking agent is a terminal hydrogen-containing linear silicone oil, and its hydrogen content is 0.75-1.25% by mass.

7. The liquid reservoir silicone rubber according to claim 3 or 4, characterized in that: The structuring control agent is hydroxy vinyl silicone oil, which has a hydroxy content of 6.5% and a vinyl content of 7% by mass.

8. The liquid reservoir silicone rubber according to claim 4, characterized in that: The internal release agent is zinc stearate.

9. A method for preparing the liquid reservoir silicone rubber according to claims 1-4, characterized in that: The following steps are involved: S1, adding methyl vinyl rubber A and methyl vinyl rubber B into an internal mixer and mixing them, and adding a structuring control agent during the mixing process; S2, after adding reinforcing fillers in batches into the internal mixer, adding hydrogen-containing cross-linking agent, inhibitor, platinum catalyst, wear-resistant additive and internal release agent into the internal mixer; S3, the mixed rubber is loaded into the liquid reservoir mold and vulcanized.

10. The preparation method according to claim 9, characterized in that In S1, the mixing temperature is 50-70°C, and after preliminary mixing for 10-15 minutes, a structuring control agent is added; And / or, in S2, the mixing temperature is ≤80°C, the shear rate is 200-300 rpm, and the mixing time is 20-30 min; And / or, in S3, the molding temperature of the liquid storage capsule mold is 120-150° C., the pressure is 8-12 MPa, and the vulcanization time is 15-25 minutes.

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