A low-modulus high-elongation silicone gel material, a preparation method and application thereof

Abstract

The application uses a chain extension crosslinking system in the preparation of silicone gel, has a significant improvement effect on the mechanical properties of the silicone gel, and the obtained product has the characteristics of low viscosity and easy control of modulus. The low modulus tensile resistant solvent-free silicone gel with controllable viscoelasticity developed by the application has a wide application prospect in the fields of electronics and adhesives.

Description

[0001] This application is a divisional application of the application filed on March 10, 2023, with application number “202310230214.7”. Technical Field

[0002] This invention belongs to the field of organosilicon elastomer technology, specifically relating to a low-modulus, high-elongation organosilicon gel material, its preparation method, and its application. Background Technology

[0003] Flexible and stretchable electronic products, which retain their electronic functions even when stretched, have shown broad application prospects in many emerging fields, such as flexible wearable electronic devices, electronic skin, and smart textiles. To construct novel flexible and stretchable electronic products, research on flexible and stretchable substrates and functional electrodes has received considerable attention. There are two main components: a soft and stretchable substrate and electrode materials adapted to the substrate.

[0004] Among various commercial elastomers, polydimethylsiloxane (PDMS) has been used to develop matrix materials that meet the mechanical properties of polymer networks, such as flexibility and tensile strength. However, with the increasing complexity and diversity of application environments and the growing demand for performance upgrades, their applications are greatly limited, for example, due to poor low-temperature mechanical properties, poor adhesion, and poor fatigue resistance.

[0005] Traditional silicone rubber materials, due to the entanglement of polydimethylsiloxane molecular chains, typically have a modulus higher than 200 kPa, which limits their application in many fields requiring low-modulus or even ultra-low-modulus elastomers. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a low-modulus, high-tensile silicone gel material, its preparation method, and its applications. By synthesizing a chain extender with a small molecular weight, the chain extender reacts with a polymer-based gel to obtain a low-modulus, tensile-resistant silicone gel. This method allows for adjustment of the modulus and tensile properties of the resulting material and is simple to operate. In particular, products with very low modulus (below 100 kPa) and high tensile properties can be obtained. Furthermore, by controlling the amount of raw materials used, products with different moduli and elongation at break can be obtained.

[0007] The technical solution of this invention is as follows: An organosilicon gel composition comprising the following components in parts by weight: (a) at least one organopolysiloxane of formula (I) as a base polymer, 100 parts; (b) organosilicon crosslinking agent, 0-20 parts; (c) organopolysiloxane chain extender of formula (III), 0.01-3 parts; (d) platinum catalyst, 0.02-0.08 parts; Formula (I) In formula (I), each R1 may be the same or different, and is independently selected from methyl or ethyl; R2, R3, R4, and R5 may be the same or different, and are independently selected from methyl, ethyl, or phenyl. R6 and R7 are vinyl groups; m is any integer between 2 and 200, and n is any integer between 10 and 200; The organosilicon crosslinking agent has the structure shown in formula (II), or is a polyvinyl polysilsesquioxane, or a vinyl MQ resin; Equation (II) In formula (II), R1, R2, R3, R4, R5, R6, R7, and R8 may be the same or different, and are independently selected from hydrogen, vinyl, methyl, or ethyl; and at least three of R1, R2, R3, R4, R5, R6, R7, and R8 are vinyl. Equation (III) In equation (III), R8, R9, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 They may be the same or different, and are independently selected from methyl, phenyl, ethyl, trifluoropropyl, cyanopropyl, and hydrogen; x is any integer between 1 and 100, for example, any integer between 10 and 50, and y is any integer between 1 and 100, for example, any integer between 10 and 50.

[0008] According to the present invention, the raw materials for the organopolysiloxane represented by formula (I) are octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, methyltrifluoropropylcyclotrisiloxane, methylethylcyclotrisiloxane, methylcyanopropylcyclosiloxane, tetramethyldivinyldisiloxane, tetramethyldisiloxane, divinyltetramethyldisiloxane, or tetramethyltetravinylcyclotetrasiloxane. For example, the organopolysiloxane represented by formula (I) is a polymer obtained by reacting octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, tetramethyldisiloxane, or divinyltetramethyldisiloxane in the presence of tetramethylammonium hydroxide.

[0009] According to the present invention, m is any integer between 10 and 100, and n is any integer between 15 and 100.

[0010] According to the present invention, the platinum catalyst is a cassiterite catalyst.

[0011] The raw material for the organopolysiloxane chain extender shown in formula (III) above is obtained by polymerizing two or more monomers selected from octamethylcyclotetrasiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, tetramethyldisiloxane, methylphenylcyclotetrasiloxane, tetramethyltetraethylcyclotetrasiloxane, methyltrifluoropropylcyclotrisiloxane, and methylcyanopropylcyclosiloxane under an acidic catalyst.

[0012] According to an embodiment of the present invention, the silicone gel composition comprises the following components in parts by weight: (a) 100 parts of the organopolysiloxane of formula (I); (b) 5-10 parts of organosilicon crosslinking agent; (c) 0.01-3 parts of the organopolysiloxane chain extender of formula (III); (d) 0.02-0.08 parts of platinum catalyst.

[0013] According to an embodiment of the present invention, the viscosity of the organopolysiloxane represented by formula (I) is 100-100000 mPa·s, for example 500 to 50000 mPa·s.

[0014] According to an embodiment of the present invention, the viscosity of the organopolysiloxane chain extender shown in formula (III) is 100-50000 mPa·s, for example 500 to 5000 mPa·s.

[0015] According to an embodiment of the present invention, the polymer represented by formula (I) serves as the base gel of the organosilicon gel and can undergo a chain extension reaction with a chain extender.

[0016] According to an embodiment of the present invention, in formula (II), R1, R3, R6, and R7 are the same and selected from ethyl; R2, R4, R5, and R8 are the same and selected from vinyl.

[0017] According to an embodiment of the present invention, the organosilicon crosslinking agent is tetramethyltetravinylcyclotetrasiloxane, vinyl MQ resin (vinyl content 2.5%), or octavinylpolysilsesquioxane.

[0018] According to a preferred embodiment of the present invention, the silicone gel composition comprises the following components in parts by weight: (a) 100 parts of the organopolysiloxane shown in formula (I); (b) 5-9 parts of organosilicon crosslinking agent; (c) the organopolysiloxane chain extender shown in formula (III) is more than 0.013 times the mass of the organosilicon crosslinking agent shown in formula (II); (d) 0.02-0.08 parts of platinum catalyst; or (a) 100 parts of the organopolysiloxane of formula (I); (b) 10 parts of organosilicon crosslinking agent; (c) 0.15-0.30 parts of the organopolysiloxane chain extender of formula (III); (d) 0.02-0.08 parts of platinum catalyst.

[0019] According to an embodiment of the present invention, the polymer raw materials in formula (III) are octamethylcyclotetrasiloxane and 1,3,5,7-tetramethylcyclotetrasiloxane; or, octamethylcyclotetrasiloxane and tetramethyldisiloxane are polymerized under an acidic catalyst such as hydrochloric acid.

[0020] According to an embodiment of the present invention, when preparing the polymer of formula (III), the acidic catalyst used is any one of hydrochloric acid, aluminum chloride, molecular sieve, dinonylnaphthalene disulfonic acid, dinonylnaphthalene sulfonic acid, dodecylbenzenesulfonic acid, p-methylbenzenesulfonic acid, and trifluoromethanesulfonic acid. Preferably, the polymer reaction catalyst of formula (III) is hydrochloric acid.

[0021] According to an embodiment of the present invention, the polymer of formula (III) is prepared using octamethylcyclotetrasiloxane and 1,3,5,7-tetramethylcyclotetrasiloxane in a molar ratio of 26:1.

[0022] According to an embodiment of the present invention, when using octamethylcyclotetrasiloxane and 1,3,5,7-tetramethylcyclotetrasiloxane to prepare the polymer of formula (III), the reaction temperature of the raw materials is 50°C-100°C, specifically 50°C, 70°C, 60°C or 100°C.

[0023] According to an embodiment of the present invention, when using octamethylcyclotetrasiloxane and 1,3,5,7-tetramethylcyclotetrasiloxane to prepare the polymer of formula (III), the reaction time of the polymer raw materials in formula (III) is 5-10 h.

[0024] According to an embodiment of the present invention, when preparing the polymer of formula (III) using octamethylcyclotetrasiloxane and 1,3,5,7-tetramethylcyclotetrasiloxane, the polymer represented by formula (III) needs to be eluted in a solvent, wherein the solvent for the reaction is one or more selected from water, methanol, ethanol, isopropanol, acetone, butanone, cyclohexanone, N,N-dimethylformamide, 1,4-dioxane, ethyl acetate, chloroform, tetrahydrofuran, toluene, o-xylene, p-xylene, and m-xylene. Preferably, the solvent for the polymer reaction is ethanol or toluene.

[0025] According to an embodiment of the present invention, in formula (III), x can be any integer between 6 and 30; y can be any integer between 10 and 20.

[0026] The present invention also provides a method for preparing the organosilicon gel as described above, comprising the following steps: The organopolysiloxane of formula (I), the organosilicon crosslinking agent, and the organopolysiloxane of formula (III) are mixed, and then a platinum catalyst is added and mixed again.

[0027] According to an embodiment of the present invention, the method further includes the step of mixing the mixture and then adding it into a tetrafluoroethylene mold for high-temperature vulcanization.

[0028] According to an embodiment of the present invention, the temperature used for high-temperature vulcanization is 40~80℃, such as 50~70℃.

[0029] According to an embodiment of the present invention, the high-temperature vulcanization time is 0.5-5 hours, for example, 1 hour.

[0030] According to an embodiment of the invention, the mixing is performed under stirring and / or ultrasonic conditions. Exemplarily, the stirring is, for example, mechanical or magnetic stirring at room temperature for 10-20 minutes; the ultrasonication is, for example, performed in an ultrasonic cleaner with a power of 100-200W for 0.5-1 hour.

[0031] According to an embodiment of the present invention, a solvent may also be used during the mixing process. When a solvent is used, the solvent is selected from any one of toluene, methanol, ethanol, acetone, chloroform, tetrahydrofuran, isopropanol, o-xylene, cyclohexanone, cyclohexane, n-hexane, ethyl acetate, p-xylene, N,N-dimethylformamide, m-xylene, and dioxane.

[0032] The present invention also provides the application of the organosilicon gel described above in the fields of flexible electronic devices, foldable mobile phone protective films, wearable devices, electronic device packaging, and thermal conductive and heat dissipation materials for electronic devices.

[0033] Beneficial effects: Compared with the prior art, the present invention uses a chain extension crosslinking system in the preparation of organosilicon gel, which significantly improves the mechanical properties of organosilicon gel, and the resulting product has the characteristics of low viscosity and easy modulus control.

[0034] The low-modulus, tensile-resistant, solvent-free organosilicon gel with controllable viscoelasticity developed in this invention has broad application prospects in the fields of electronics and adhesives. Attached Figure Description

[0035] Figure 1 The image shows the silicon nuclear magnetic resonance spectrum of the organopolysiloxane polymer obtained in Example 1.

[0036] Figure 2 The image shows the NMR silicon spectrum of the organopolysiloxane chain extender polymer obtained in Example 2. Detailed Implementation

[0037] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory 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 covered within the scope of protection intended by the present invention.

[0038] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0039] The physical and mechanical properties of the materials obtained in the following examples were tested using GB / T 528-1998.

[0040] Example 1 Preparation of organopolysiloxane: 100g of octamethylcyclotetrasiloxane, 5.6g of tetramethyltetravinylcyclotetrasiloxane, 5.5g of tetramethyldisiloxane, 5.4g of divinyltetramethyldisiloxane, and 0.1g of tetramethylammonium hydroxide were added to a 250ml three-necked flask. Under a nitrogen atmosphere, the mixture was heated to 90℃ and reacted for 10h to achieve equilibrium. After the reaction was complete, the temperature was increased to 150℃ and maintained for 2h to decompose and destroy the catalyst. Finally, the temperature was lowered to 120℃, and low-molecular-weight substances were removed under vacuum until no distillate was obtained. The temperature was then lowered, the pressure was stopped, and the mixture was discharged after cooling to obtain the organopolysiloxane shown in formula (I).

[0041]

[0042] Formula (I) In Equation I, m is 10 and n is 15; Among them, R2, R3, R4, and R5 may be the same or different, and are independently selected from methyl, ethyl, or phenyl.

[0043] R6 and R7 are vinyl or hydrogen-based, and at least one of R6 and R7 is vinyl.

[0044] Example 2 Preparation of organopolysiloxane chain extender: 200g of octamethylcyclotetrasiloxane, 4.4g of tetramethyldisiloxane, and 0.15g of hydrochloric acid were added to a 250ml three-necked flask. The mixture was heated in a water bath to 70℃ under a nitrogen atmosphere and allowed to equilibrate for 20h. After the reaction was complete, the temperature was lowered to 50℃, and anhydrous ethanol was added and stirred. The mixture was allowed to stand and separate into layers. This process was repeated three times. The organopolysiloxane chain extender was then washed off, and excess anhydrous ethanol was distilled off using a rotary evaporator to obtain the organopolysiloxane chain extender (Formula III).

[0045]

[0046] Equation (III) In Equation III, x is 20 and y is 15; Among them, R2, R3, R4, and R5 may be the same or different, and are independently selected from methyl, ethyl, or phenyl.

[0047] R6 and R7 are vinyl or hydrogen-based, and at least one of R6 and R7 is vinyl.

[0048] Example 3 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane prepared in Example 1, 5 parts of organosilicon crosslinking agent, and 0.25 parts of organopolysiloxane chain extender prepared in Example 2 into a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0049] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0050] Example 4 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 6 parts of organosilicon crosslinking agent and 0.26 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0051] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0052] Example 5 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 7 parts of organosilicon crosslinking agent and 0.27 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0053] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0054] Example 6 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 8 parts of organosilicon crosslinking agent and 0.28 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0055] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0056] Example 7 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 9 parts of organosilicon crosslinking agent and 0.29 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0057] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0058] Example 8 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 10 parts of organosilicon crosslinking agent and 0.30 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0059] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0060] Example 9 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 5 parts of organosilicon crosslinking agent and 0.19 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0061] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0062] Example 10 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 6 parts of organosilicon crosslinking agent and 0.2 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0063] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0064] Example 11 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 7 parts of organosilicon crosslinking agent and 0.21 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0065] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0066] Example 12 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 8 parts of organosilicon crosslinking agent and 0.22 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0067] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0068] Example 13 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 9 parts of organosilicon crosslinking agent and 0.23 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0069] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0070] Example 14 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 10 parts of organosilicon crosslinking agent and 0.24 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0071] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0072] Example 15 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 5 parts of organosilicon crosslinking agent and 0.13 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0073] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0074] Example 16 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 6 parts of organosilicon crosslinking agent and 0.14 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0075] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0076] Example 17 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 7 parts of organosilicon crosslinking agent and 0.15 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0077] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0078] Example 18 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 8 parts of organosilicon crosslinking agent and 0.16 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0079] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0080] Example 19 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 9 parts of organosilicon crosslinking agent and 0.17 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0081] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0082] Example 20 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 10 parts of organosilicon crosslinking agent and 0.18 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0083] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0084] Example 21 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 5 parts of organosilicon crosslinking agent and 0.07 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0085] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0086] Example 22 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 6 parts of organosilicon crosslinking agent and 0.08 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0087] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0088] Example 23 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 7 parts of organosilicon crosslinking agent and 0.09 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0089] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0090] Example 24 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 8 parts of organosilicon crosslinking agent and 0.1 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0091] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0092] Example 25 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 9 parts of organosilicon crosslinking agent and 0.11 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0093] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0094] Example 26 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 10 parts of organosilicon crosslinking agent and 0.12 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0095] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0096] Example 27 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 5 parts of organosilicon crosslinking agent and 0.01 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0097] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0098] Example 28 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 6 parts of organosilicon crosslinking agent and 0.02 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0099] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0100] Example 29 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 7 parts of organosilicon crosslinking agent and 0.03 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0101] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0102] Example 30 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 8 parts of organosilicon crosslinking agent and 0.04 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0103] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0104] Example 31 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 9 parts of organosilicon crosslinking agent and 0.05 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0105] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0106] Example 32 Preparation steps of low modulus and high elongation organosilicon gel film (1): Add 100 parts of organopolysiloxane, 10 parts of organosilicon crosslinking agent and 0.06 parts of organopolysiloxane chain extender to a beaker and mix evenly. Stir at 300 rpm for 5-10 min, then add 0.02 parts of platinum catalyst and stir at 100 rpm. Vacuum at room temperature to obtain the mixture.

[0107] Step (2): Add the mixture from step (1) into a polytetrafluoroethylene mold, and place the mold containing the mixture into an oven at 60°C for 1 hour to obtain a low-modulus, high-elongation silicone gel film.

[0108] The crosslinking agent used in Examples 3-20 was vinyl MQ resin (vinyl content 2.5%), the crosslinking agent used in Examples 21-26 was tetramethyltetravinylcyclotetrasiloxane, and the crosslinking agent used in Examples 27-32 was octavinylpolysilsesquioxane.

[0109] The performance of the silicone gel films obtained in Examples 3-32 was tested, and the results are given in Table 1.

[0110] Table 1

[0111] As can be seen from the data in Table 1, the present invention has successfully prepared a low-modulus, high-elongation silicone gel film with modulus controlled in the range of 0.1~500KPa and elongation at break of more than 1500%. Furthermore, products with different moduli and elongations can be obtained by controlling the amount of raw materials used.

[0112] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An organosilicon gel composition, characterized in that, It comprises the following components in parts by mass: (a) 100 parts of organopolysiloxane; (b) 5-9 parts of organosilicon crosslinking agent; (c) The amount of organopolysiloxane chain extender is more than 0.013 times the mass of organosilicon crosslinking agent; (d) 0.02-0.08 parts platinum catalyst; or (a) 100 parts of organopolysiloxane; (b) 10 parts of organosilicon crosslinking agent; (c) 0.15-0.30 parts of organopolysiloxane chain extender; (d) 0.02-0.08 parts platinum catalyst; The organopolysiloxane is a polymer obtained by reacting octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, tetramethyldisiloxane, and divinyltetramethyldisiloxane in the presence of tetramethylammonium hydroxide. The organosilicon crosslinking agent is tetramethyltetravinylcyclotetrasiloxane, vinyl MQ resin (vinyl content 2.5%), or octavinylpolysilsesquioxane; The raw material for the organopolysiloxane chain extender is obtained by polymerizing two or more monomers selected from octamethylcyclotetrasiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, tetramethyldisiloxane, methylphenylcyclotetrasiloxane, tetramethyltetraethylcyclotetrasiloxane, methyltrifluoropropylcyclotrisiloxane, and methylcyanopropylcyclosiloxane under an acidic catalyst. The platinum catalyst is a cassiterite catalyst.

2. The organosilicon gel composition according to claim 1, characterized in that, The viscosity of organopolysiloxanes ranges from 500 to 50,000 mPa·s.

3. The organosilicon gel composition according to claim 1 or 2, characterized in that, The viscosity of organopolysiloxane chain extenders is 500 to 5000 mPa·s.

4. The organosilicon gel composition according to any one of claims 1-3, characterized in that, The organopolysiloxane chain extender is octamethylcyclotetrasiloxane and 1,3,5,7-tetramethylcyclotetrasiloxane; or, it is formed by the polymerization of octamethylcyclotetrasiloxane and tetramethyldisiloxane under an acidic catalyst.

5. The organosilicon gel composition according to claim 4, characterized in that, The acidic catalyst is any one of hydrochloric acid, aluminum chloride, molecular sieve, dinonylnaphthalene disulfonic acid, dinonylnaphthalene sulfonic acid, dodecylbenzene sulfonic acid, p-methylbenzene sulfonic acid, and trifluoromethanesulfonic acid.

6. The organosilicon gel composition according to claim 4, characterized in that, When preparing organopolysiloxane chain extenders from octamethylcyclotetrasiloxane and 1,3,5,7-tetramethylcyclotetrasiloxane, the molar ratio of the raw materials is 26:

1.

7. A method for preparing the organosilicon gel composition according to any one of claims 1-6, characterized in that, Includes the following steps: The organopolysiloxane, organosilicon crosslinking agent, and organopolysiloxane chain extender are mixed, and then a platinum catalyst is added and mixed again.

8. The preparation method according to claim 7, characterized in that, The method also includes the step of mixing the mixture and then adding it into a tetrafluoroethylene mold for high-temperature vulcanization; The temperature used for high-temperature vulcanization is 40~80℃; the high-temperature vulcanization time is 0.5-5h.

9. The preparation method according to claim 8, characterized in that, The temperature used for high-temperature vulcanization is 50~70℃; Preferably, the high-temperature vulcanization time is 1 hour.

10. The application of the organosilicon gel composition according to any one of claims 1-6 in the fields of flexible electronic devices, foldable mobile phone protective films, wearable devices, electronic device packaging, and thermal conductive and heat dissipation materials for electronic devices.

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