A reinforced self-curing silicone rubber composite packaging material and its preparation method

Abstract

This invention discloses an enhanced self-curing silicone rubber composite packaging material and its preparation method. The composite packaging material has a double-layer structure, including an outer fast-curing layer and an inner moisture-releasing reinforcing layer. The outer fast-curing layer comprises hydroxyl-terminated polydimethylsiloxane, reinforcing filler, crosslinking agent, catalyst, and hydrophilic moisture-promoting filler. The inner moisture-releasing reinforcing layer comprises hydroxyl-terminated polydimethylsiloxane, reinforcing filler, crosslinking agent, catalyst, moisture-releasing filler, and surface-modified short fibers. The moisture-releasing filler is a porous particle with adsorbed moisture and a hydrophobic polysiloxane coating on its surface. The surface-modified short fibers are aramid short fibers or glass short fibers grafted with a silane coupling agent. The enhanced self-curing silicone rubber composite packaging material provided by this invention, through a bidirectional curing mechanism of rapid film formation in the outer layer and slow moisture release in the inner layer, significantly shortens the deep curing time and improves the mechanical strength after curing while ensuring storage stability and construction flexibility.

Description

Technical Field

[0001] This invention belongs to the technical field of insulation, protection and sealing materials, specifically relating to an enhanced self-curing silicone rubber composite packaging material and its preparation method. Background Technology

[0002] Self-curing silicone rubber is a one-component elastomer material based on hydroxyl-terminated polydimethylsiloxane, which undergoes condensation cross-linking under the influence of moisture. Because it requires no heating or pressurization during construction, relying solely on ambient moisture to gradually cure from the surface inwards, and exhibits excellent electrical insulation, weather resistance, and hydrophobic and moisture-proof properties after curing, it is widely used in the insulation protection and waterproof sealing of outdoor equipment such as power cable joints, overhead line clamps, rail transit electrical connection points, and communication base station antenna interfaces. Compared with traditional heat shrink tubing and waterproof tape, self-curing silicone rubber packaging can tightly adhere to irregularly shaped workpieces, eliminating the problem of protective failure due to inadequate heat shrinkage or tape loosening, demonstrating significant technical advantages.

[0003] However, existing self-curing silicone rubber packaging materials still have the following technical drawbacks in practical engineering applications. Firstly, the deep curing speed is slow. The moisture curing mechanism of self-curing silicone rubber dictates that the cross-linking reaction proceeds layer by layer from the material surface inwards. When the packaging thickness exceeds 1.5 mm, the path for water molecules to diffuse into the material's interior is significantly prolonged, and complete internal curing often requires tens of hours or even several days. This not only prolongs construction waiting time, but is particularly inconvenient in emergency repairs or high-altitude operations. Simultaneously, the shrinkage stress caused by asynchronous internal and external curing can lead to peeling of the coating layer from the workpiece interface or the formation of microcracks within, affecting long-term protective effects. To accelerate deep curing, existing technologies have attempted to add hygroscopic porous materials or hydrophilic polymers to the formulation. However, these additives tend to absorb moisture prematurely during storage, triggering slow cross-linking, resulting in a shortened shelf life of the packaging material and a decrease in mechanical properties after curing.

[0004] Secondly, it is difficult to balance mechanical strength and construction flexibility. Self-curing silicone rubber packaging materials require sufficient elongation and plasticity when uncured to wrap and cover workpieces of different shapes; they also require high tensile and tear strength after curing to withstand subsequent mechanical stresses such as wind vibration and thermal expansion and contraction. To improve strength, a large amount of reinforcing filler (such as fumed silica) or short fibers are usually required, but this significantly reduces the flowability and elongation at break of the uncured material, making it difficult for the packaging material to adhere properly and causing wrinkles or interlayer gaps during wrapping. Although aramid short fiber reinforcement has a good effect, the interfacial bonding force between ordinary untreated fibers and the silicone rubber matrix is ​​weak, and the fibers are easily pulled out, resulting in limited reinforcement effect.

[0005] Furthermore, a single formulation cannot simultaneously achieve rapid surface drying and internal moisture control. An ideal self-curing packaging material should possess the characteristics of "rapid surface film formation and continuous internal curing." While increasing the overall catalyst content to accelerate curing can shorten surface drying time, it reduces the stability of the compound during storage, and the concentrated heat release during curing can easily cause internal bubbles or cracks. Conversely, reducing the catalyst dosage to extend shelf life results in a curing speed that does not meet on-site construction requirements. Currently, there is a lack of a self-curing silicone rubber packaging material that can achieve rapid surface drying, ensure deep and uniform curing, and simultaneously maintain good application flexibility and high mechanical strength. Summary of the Invention

[0006] To address the aforementioned technical problems, the present invention aims to provide an enhanced self-curing silicone rubber composite packaging material and its preparation method. The enhanced self-curing silicone rubber composite packaging material provided by the present invention, through a bidirectional curing mechanism of rapid film formation in the outer layer and slow moisture release in the inner layer, significantly shortens the deep curing time and improves the mechanical strength after curing, while ensuring storage stability and construction flexibility.

[0007] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution: The present invention provides an enhanced self-curing silicone rubber composite packaging material, wherein the composite packaging material has a double-layer structure, including an outer fast-curing layer and an inner moisture-releasing reinforcing layer; The outer fast-curing layer comprises hydroxyl-terminated polydimethylsiloxane, reinforcing filler, crosslinking agent, catalyst, and hydrophilic moisture-inducing filler; The inner moisture-release reinforcing layer comprises hydroxyl-terminated polydimethylsiloxane, reinforcing filler, crosslinking agent, catalyst, moisture-release filler, and surface-modified short fibers. The moisture-releasing filler is a porous particle that adsorbs moisture and has a hydrophobic polysiloxane coating on its surface. The surface-modified short fibers are aramid short fibers or glass short fibers grafted with silane coupling agents.

[0008] Preferably, the porous particles of the moisture-releasing filler are zeolite molecular sieves or diatomaceous earth, and the mass percentage of water adsorbed is 10% to 30%. The hydrophobic polysiloxane coating layer is a polysiloxane layer formed by cross-linking through heat treatment.

[0009] Preferably, the length of the surface-modified short fiber is 3-6 mm, and the silane coupling agent is γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, or γ-mercaptopropyltrimethoxysilane.

[0010] Preferably, the catalyst in the outer fast-curing layer has a mass percentage content of 2-3 wt% of hydroxyl-terminated polydimethylsiloxane, and the catalyst in the inner moisture-releasing reinforcing layer has a mass percentage content of 0.5-1.5 wt% of hydroxyl-terminated polydimethylsiloxane.

[0011] Preferably, the hydrophilic moisture-promoting filler is hydrophilic fumed silica with a specific surface area ≥200 m² / g.

[0012] Preferably, the total thickness of the composite packaging material is 0.8~3.0mm, wherein the outer fast-curing layer has a thickness of 0.2~0.5mm and the inner moisture-releasing reinforcing layer has a thickness of 0.6~2.5mm.

[0013] Preferably, by weight, The outer fast-curing layer formula is: 100 parts of hydroxyl-terminated polydimethylsiloxane, 15-30 parts of reinforcing filler, 5-10 parts of crosslinking agent, 2-3 parts of catalyst, 3-8 parts of hydrophilic moisture-promoting filler, and 1-3 parts of silane coupling agent. The formula for the inner moisture-release reinforcing layer is as follows: 100 parts of hydroxyl-terminated polydimethylsiloxane, 10-25 parts of reinforcing filler, 5-10 parts of crosslinking agent, 0.5-1.5 parts of catalyst, 10-25 parts of moisture-release filler, 5-15 parts of surface-modified short fiber, and 1-3 parts of silane coupling agent.

[0014] Furthermore, when the composite packaging material is used, the outer fast-curing layer rapidly cross-links into a film upon contact with ambient moisture, while the inner moisture-releasing filler slowly releases internal moisture under construction compression and moisture penetration, thus achieving bidirectional curing of the inner layer from the inside out and from the outside in together with the external moisture.

[0015] Another aspect of the present invention provides a method for preparing an enhanced self-curing silicone rubber composite packaging material, comprising the following steps: (1) Preparation of moisture-release filler: Dry porous particles are subjected to surface hydrophobic modification treatment to form a hydrophobic polysiloxane coating layer. Then the coated particles are placed in water and the particles are pressurized to adsorb water to obtain moisture-release filler. (2) Preparation of surface-modified short fibers: The short fibers are surface-treated with a silane coupling agent to obtain surface-modified short fibers; (3) Prepare the outer layer composition and the inner layer composition separately: Mix the components evenly and degas under vacuum; (4) Double-layer co-extrusion molding: The outer layer composition and the inner layer composition are co-extruded to form a double-layer sheet, which is then wound up and covered with a release film; (5) Packaging: The rolled-up sheet is vacuum-sealed with nitrogen filling.

[0016] Further, the hydrophobic modification treatment in step (1) includes: mixing dried porous particles with a thermally crosslinkable polysiloxane composition under anhydrous conditions, heating and crosslinking at 60~100℃ for 0.5~2h to form a hydrophobic polysiloxane coating layer; the method of adsorbing moisture is: immersing the coated particles in deionized water, maintaining it under a pressure of 0.5~1.0MPa for 12~24h, and then quickly drying the surface after removal to obtain a moisture-releasing filler; the surface treatment temperature in step (2) is 60~80℃ and the time is 1~3h; the co-extrusion temperature in step (4) is room temperature~40℃.

[0017] The beneficial effects of this invention are as follows: This invention achieves functional separation through a dual-layer structure design: the high content of catalyst in the outer fast-curing layer works synergistically with the hydrophilic moisture-promoting filler to rapidly form a dense skin after the packaging material comes into contact with ambient moisture, effectively isolating excessive external moisture penetration and preventing premature escape of internal moisture; the porous particles in the inner moisture-releasing reinforcing layer, which pre-adsorb moisture and are coated with hydrophobic polysiloxane, remain stable during storage due to the barrier of the hydrophobic coating layer. During use, they gradually release internal moisture under construction pressure and moisture penetration, forming a bidirectional curing channel from the inside out and from the outside in together with external moisture, thereby significantly shortening the time required for complete deep curing and overcoming the defects of traditional single-layer materials, such as limited curing depth and asynchronous internal and external curing.

[0018] Meanwhile, the surface-modified short fibers in the inner layer form a strong chemical bond with the silicone rubber matrix through a silane coupling agent. In the uncured stage, the rational design of fiber content and length distribution maintains a high elongation at break, giving the packaging material excellent construction flexibility, enabling it to closely fit irregularly shaped workpieces without wrinkles or interlayer gaps. After complete curing, the good interfacial bonding between the fibers and the matrix, as well as the absence of weak interfacial areas caused by the co-extrusion of the inner and outer layers, allow the composite material to simultaneously obtain high tensile strength and tear resistance, resolving the contradiction between mechanical strength and ease of construction.

[0019] Furthermore, the synergy between the outer high-catalysis system and the inner moisture-controlled filler avoids the problem of decreased storage stability caused by the overall increase in catalyst content. Combined with vacuum-nitrogen-filled sealed packaging, the packaging material can be stored at room temperature for a long time without premature cross-linking. Moreover, all components use mature industrial raw materials and co-extrusion processes, eliminating the need for pre-curing treatment and facilitating large-scale production. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] This invention provides a reinforced self-curing silicone rubber composite packaging material, which has a two-layer structure, comprising an outer fast-curing layer and an inner moisture-releasing reinforcing layer. The outer fast-curing layer comprises hydroxyl-terminated polydimethylsiloxane, reinforcing filler, crosslinking agent, catalyst, and hydrophilic moisture-promoting filler. The inner moisture-releasing reinforcing layer comprises hydroxyl-terminated polydimethylsiloxane, reinforcing filler, crosslinking agent, catalyst, moisture-releasing filler, and surface-modified short fibers. The moisture-releasing filler is a porous particle with adsorbed moisture and a hydrophobic polysiloxane coating on its surface; the surface-modified short fibers are aramid short fibers or glass short fibers grafted with a silane coupling agent.

[0022] In a preferred embodiment, the porous particles of the moisture-releasing filler are selected from zeolite molecular sieves or diatomaceous earth, and their adsorbed water content is 10% to 30% by mass. The hydrophobic polysiloxane coating layer is a polysiloxane layer formed by cross-linking through heat treatment. This coating layer can effectively prevent internal moisture from escaping during storage, and gradually releases moisture under construction pressure and moisture permeation during use.

[0023] In another preferred embodiment, the length of the surface-modified short fibers is 3–6 mm. The silane coupling agent may be selected from one or more of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, or γ-mercaptopropyltrimethoxysilane. By performing silane grafting treatment on the short fibers, the interfacial bonding strength between the fibers and the silicone rubber matrix can be significantly improved.

[0024] To balance surface drying speed and storage stability, the catalyst content in the outer fast-curing layer is 2–3 wt% of hydroxyl-terminated polydimethylsiloxane, while the catalyst content in the inner moisture-releasing reinforcing layer is controlled at 0.5–1.5 wt% of hydroxyl-terminated polydimethylsiloxane. The higher catalyst content in the outer layer, combined with hydrophilic moisture-promoting fillers, allows the packaging material to rapidly cross-link and form a film upon contact with ambient moisture. The lower catalyst content in the inner layer avoids concentrated localized heat release during curing and, in conjunction with the moisture-releasing fillers, achieves uniform curing.

[0025] For example, the hydrophilic moisture-enhancing filler can be hydrophilic fumed silica with a specific surface area ≥200 m². 2 / g, this type of filler has good moisture adsorption and conduction capabilities, which helps to accelerate the curing of the outer layer.

[0026] In terms of thickness design, the total thickness of the composite packaging material can be 0.8–3.0 mm, with the outer fast-curing layer being 0.2–0.5 mm thick and the inner moisture-releasing reinforcing layer being 0.6–2.5 mm thick. This thickness ratio ensures both rapid surface drying and sufficient internal reinforcement and moisture retention.

[0027] An exemplary formulation (by weight) is as follows: In the outer fast-curing layer, 100 parts of hydroxyl-terminated polydimethylsiloxane, 15-30 parts of reinforcing filler, 5-10 parts of crosslinking agent, 2-3 parts of catalyst, 3-8 parts of hydrophilic moisture-inducing filler, and 1-3 parts of silane coupling agent; In the inner moisture-releasing reinforcing layer, 100 parts of hydroxyl-terminated polydimethylsiloxane, 10-25 parts of reinforcing filler, 5-10 parts of crosslinking agent, 0.5-1.5 parts of catalyst, 10-25 parts of moisture-releasing filler, 5-15 parts of surface-modified short fibers, and 1-3 parts of silane coupling agent. The reinforcing filler can be fumed silica or precipitated silica, the crosslinking agent can be methyltrimethoxysilane or tetraethyl orthosilicate, and the catalyst can be an organotin compound such as dibutyltin dilaurate.

[0028] When in use, the working mechanism of the composite packaging material of the present invention is as follows: the outer fast-curing layer quickly cross-links into a dense film after contacting the ambient moisture, preventing excessive loss of internal moisture and blocking external impurities; the inner moisture-releasing filler slowly releases the pre-adsorbed moisture under the action of construction extrusion and moisture penetration. This moisture, together with the external moisture that penetrates from the outer layer, enables the inner layer to achieve bidirectional curing from the inside out and from the outside in, thereby significantly shortening the time required for complete deep curing.

[0029] The present invention also provides a method for preparing the above-mentioned reinforced self-curing silicone rubber composite packaging material, comprising the following steps: (1) Preparation of moisture-release filler: Dry porous particles are subjected to surface hydrophobic modification treatment to form a hydrophobic polysiloxane coating layer. Then the coated particles are placed in water and the particles are pressurized to adsorb water to obtain moisture-release filler. (2) Preparation of surface-modified short fibers: The short fibers are surface-treated with a silane coupling agent to obtain surface-modified short fibers; (3) Prepare the outer layer composition and the inner layer composition separately: Mix the components evenly and degas under vacuum; (4) Double-layer co-extrusion molding: The outer layer composition and the inner layer composition are co-extruded to form a double-layer sheet, which is then wound up and covered with a release film; (5) Packaging: The rolled-up sheet is vacuum-sealed with nitrogen filling.

[0030] In a preferred embodiment, the hydrophobic modification treatment in step (1) specifically includes: under anhydrous conditions, mixing dried porous particles with a thermally crosslinkable polysiloxane composition (e.g., terminal vinyl polydimethylsiloxane, hydrogen-containing silicone oil, and platinum catalyst), and heating and crosslinking at 60~100℃ for 0.5~2h to form a hydrophobic polysiloxane coating layer; the method of adsorbing moisture is: immersing the coated particles in deionized water, maintaining a pressure of 0.5~1.0MPa for 12~24h, and then quickly drying the surface after removal to obtain a moisture-releasing filler. In step (2), the surface treatment temperature of the short fibers is preferably 60~80℃, and the time is preferably 1~3h. In step (4), the extrusion temperature of the double-layer co-extrusion is preferably room temperature to 40℃, and no pre-curing treatment is required; the fibers are directly wound up and coated. In step (5), the vacuum-nitrogen-filled sealing packaging is preferably vacuumed to below -0.09MPa, then filled with nitrogen and heat-sealed. This can minimize the intrusion of moisture or the loss of internal moisture during storage and ensure long-term storage stability.

[0031] The above preparation methods are simple, employing commonly used mixing and co-extrusion equipment in the rubber industry. They eliminate the need for complex multi-layer co-extrusion positioning or pre-curing steps, facilitating continuous production. The resulting double-layer composite packaging material exhibits excellent flexibility and elongation even before curing, allowing for easy wrapping around various irregularly shaped workpieces. During storage, the hydrophobic coating of the moisture-releasing filler and the vacuum nitrogen-filled packaging ensure a usable lifespan of over 12 months. In use, the dual-curing mechanism significantly shortens the deep curing time, and the cured mechanical strength and electrical insulation properties meet the requirements for long-term outdoor operation.

[0032] Example 1

[0033] This embodiment provides an enhanced self-curing silicone rubber composite packaging material with a total thickness of 2.0 mm, wherein the outer fast-curing layer has a thickness of 0.3 mm and the inner moisture-releasing reinforcing layer has a thickness of 1.7 mm.

[0034] Outer fast-curing layer formulation (parts by weight): 100 parts of hydroxyl-terminated polydimethylsiloxane (viscosity 20000 mPa·s), fumed silica (specific surface area 150 m² / s). 2 20 parts ( / g), 8 parts methyltrimethoxysilane, 2.5 parts dibutyltin dilaurate, and hydrophilic fumed silica (specific surface area 200m²). 2 5 parts of ( / g), 2 parts of γ-aminopropyltriethoxysilane.

[0035] The formulation of the inner moisture-release reinforcing layer (parts by weight) is as follows: 100 parts of hydroxyl-terminated polydimethylsiloxane (viscosity 20000 mPa·s), 15 parts of fumed silica, 8 parts of methyltrimethoxysilane, 1.0 part of dibutyltin dilaurate, 18 parts of moisture-release filler, 10 parts of modified aramid short fiber (length 4 mm, treated with γ-aminopropyltriethoxysilane), and 2 parts of γ-aminopropyltriethoxysilane.

[0036] Preparation process: (I) Preparation of Moisture-Release Packing Material: Dry 4A zeolite molecular sieve (average pore size 0.4 nm) was mixed uniformly with a thermally crosslinkable polysiloxane composition at a mass ratio of 100:5. The thermally crosslinkable polysiloxane composition consisted of vinyl-terminated polydimethylsiloxane (viscosity 500 mPa·s), hydrogen-containing silicone oil (hydrogen mass fraction 0.5%), and a platinum catalyst (10 ppm platinum). Under anhydrous nitrogen protection, the mixture was heated at 80°C for 1 hour to crosslink, forming a crosslinked hydrophobic polysiloxane coating layer on the surface of the zeolite particles. The coated particles were then placed in an autoclave, deionized water was added, and the pressure was increased to 0.8 MPa and maintained for 24 hours, allowing water to enter the pores through the microscopic defects of the coating layer. After removal, the surface moisture was quickly absorbed with filter paper, and the moisture content was measured to be 18%, thus obtaining the moisture-release packing material.

[0037] (II) Preparation of surface-modified short fibers: Aramid short fibers with a length of 4 mm were immersed in an ethanol / water (95:5) solution of 2% γ-aminopropyltriethoxysilane and stirred at 70°C for 2 hours. After being removed, they were dried at 110°C for 1 hour to obtain surface-modified aramid short fibers.

[0038] (III) Molding of composite packaging materials: Weigh 100 parts of hydroxyl-terminated polydimethylsiloxane and fumed silica (specific surface area 150m²) according to the outer layer formula. 2 20 parts ( / g), 8 parts methyltrimethoxysilane, 2.5 parts dibutyltin dilaurate, and hydrophilic fumed silica (specific surface area 200m²). 2 5 parts of γ-aminopropyltriethoxysilane ( / g) and 2 parts of γ-aminopropyltriethoxysilane were mixed evenly and then degassed under vacuum to obtain the outer layer composition. According to the inner layer formula, 100 parts of terminal hydroxyl polydimethylsiloxane, 15 parts of fumed silica, 8 parts of methyltrimethoxysilane, 1.0 part of dibutyltin dilaurate, 18 parts of the above-mentioned moisture-release filler, 10 parts of the above-mentioned surface-modified aramid short fiber, and 2 parts of γ-aminopropyltriethoxysilane were weighed, mixed evenly, and then degassed under vacuum to obtain the inner layer composition. Using a double-layer co-extrusion die, the outer and inner layer compositions were co-extruded at 30°C to form a double-layer sheet with an outer layer thickness of 0.3 mm and an inner layer thickness of 1.7 mm. The sheet was then wound up and covered with a release film. Finally, the wound sheet was vacuum-sealed with nitrogen (vacuumed to -0.095 MPa, filled with nitrogen, and then heat-sealed).

[0039] The resulting product has an uncured elongation at break of 520%, a cured tensile strength of 5.0 MPa, and a deep curing time of approximately 4 hours.

[0040] Example 2

[0041] The difference between this embodiment and Example 1 is that the 4A zeolite molecular sieve in Example 1 is replaced with diatomaceous earth to prepare the moisture-release filler, and the modified short fibers are glass short fibers (5 mm in length, treated with γ-glycidoxypropyltrimethoxysilane). The amount of hydrophilic fumed silica in the outer layer is changed to 6 parts. The total thickness is 1.5 mm, with the outer layer being 0.2 mm and the inner layer being 1.3 mm. Everything else is the same. The resulting product has an uncured elongation at break of 550%, a tensile strength of 4.6 MPa after curing, and a deep curing time of approximately 3.5 hours.

[0042] Example 3

[0043] The difference between this embodiment and Embodiment 1 is that the content of the outer catalyst is adjusted to 3.0 parts, the content of the inner catalyst is adjusted to 0.8 parts, and the amount of moisture-releasing filler in the inner layer is increased to 22 parts (the preparation method is the same as in Embodiment 1, and the moisture content is obtained by controlling the duration or pressure of pressurized water absorption). The total thickness is 2.5 mm, with the outer layer at 0.4 mm and the inner layer at 2.1 mm. The resulting product has an uncured elongation at break of 490%, a tensile strength of 5.2 MPa after curing, and a deep curing time of approximately 5 hours.

[0044] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0045] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A reinforced self-curing silicone rubber composite packaging material, characterized in that, The composite packaging material has a double-layer structure, including an outer fast-curing layer and an inner moisture-releasing reinforcing layer; The outer fast-curing layer comprises hydroxyl-terminated polydimethylsiloxane, reinforcing filler, crosslinking agent, catalyst, and hydrophilic moisture-inducing filler; The inner moisture-release reinforcing layer comprises hydroxyl-terminated polydimethylsiloxane, reinforcing filler, crosslinking agent, catalyst, moisture-release filler, and surface-modified short fibers. The moisture-releasing filler is a porous particle that adsorbs moisture and has a hydrophobic polysiloxane coating on its surface. The surface-modified short fibers are aramid short fibers or glass short fibers grafted with silane coupling agents.

2. The reinforced self-curing silicone rubber composite packaging material according to claim 1, characterized in that, The porous particles of the moisture-releasing filler are zeolite molecular sieves or diatomaceous earth, and the mass percentage of water adsorbed is 10% to 30%. The hydrophobic polysiloxane coating layer is a polysiloxane layer formed by cross-linking through heat treatment.

3. The reinforced self-curing silicone rubber composite packaging material according to claim 1, characterized in that, The length of the surface-modified short fiber is 3-6 mm, and the silane coupling agent is γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, or γ-mercaptopropyltrimethoxysilane.

4. The reinforced self-curing silicone rubber composite packaging material according to claim 1, characterized in that, The catalyst in the outer fast-curing layer has a mass percentage of 2-3 wt% of hydroxyl-terminated polydimethylsiloxane, and the catalyst in the inner moisture-releasing reinforcing layer has a mass percentage of 0.5-1.5 wt% of hydroxyl-terminated polydimethylsiloxane.

5. The reinforced self-curing silicone rubber composite packaging material according to claim 1, characterized in that, The hydrophilic moisture-enhancing filler is hydrophilic fumed silica with a specific surface area ≥200 m². 2 / g.

6. The reinforced self-curing silicone rubber composite packaging material according to claim 1, characterized in that, The total thickness of the composite packaging material is 0.8~3.0 mm, of which the outer fast-curing layer has a thickness of 0.2~0.5 mm and the inner moisture-releasing reinforcing layer has a thickness of 0.6~2.5 mm.

7. The reinforced self-curing silicone rubber composite packaging material according to claim 1, characterized in that, By weight, The outer fast-curing layer formula is: 100 parts of hydroxyl-terminated polydimethylsiloxane, 15-30 parts of reinforcing filler, 5-10 parts of crosslinking agent, 2-3 parts of catalyst, 3-8 parts of hydrophilic moisture-promoting filler, and 1-3 parts of silane coupling agent. The formula for the inner moisture-release reinforcing layer is as follows: 100 parts of hydroxyl-terminated polydimethylsiloxane, 10-25 parts of reinforcing filler, 5-10 parts of crosslinking agent, 0.5-1.5 parts of catalyst, 10-25 parts of moisture-release filler, 5-15 parts of surface-modified short fiber, and 1-3 parts of silane coupling agent.

8. The reinforced self-curing silicone rubber composite packaging material according to claim 1, characterized in that, When the composite packaging material is used, the outer fast-curing layer rapidly cross-links to form a film upon contact with ambient moisture, while the inner moisture-releasing filler slowly releases internal moisture under construction compression and moisture penetration, achieving bidirectional curing of the inner layer from the inside out and from the outside in together with the external moisture.

9. A method for preparing a reinforced self-curing silicone rubber composite packaging material according to any one of claims 1-8, characterized in that, Includes the following steps: (1) Preparation of moisture-release filler: Dry porous particles are subjected to surface hydrophobic modification treatment to form a hydrophobic polysiloxane coating layer. Then the coated particles are placed in water and the particles are pressurized to adsorb water to obtain moisture-release filler. (2) Preparation of surface-modified short fibers: The short fibers are surface-treated with a silane coupling agent to obtain surface-modified short fibers; (3) Prepare the outer layer composition and the inner layer composition separately: Mix the components evenly and degas under vacuum; (4) Double-layer co-extrusion molding: The outer layer composition and the inner layer composition are co-extruded to form a double-layer sheet, which is then wound up and covered with a release film; (5) Packaging: The rolled-up sheet is vacuum-sealed with nitrogen filling.

10. The preparation method according to claim 9, characterized in that, The hydrophobic modification treatment in step (1) includes: mixing dried porous particles with a thermally crosslinkable polysiloxane composition under anhydrous conditions, heating and crosslinking at 60~100℃ for 0.5~2h to form a hydrophobic polysiloxane coating layer; the method of adsorbing moisture is: immersing the coated particles in deionized water, maintaining it under a pressure of 0.5~1.0MPa for 12~24h, and then quickly drying the surface after removal to obtain a moisture-releasing filler; the surface treatment temperature in step (2) is 60~80℃ and the time is 1~3h; the co-extrusion temperature in step (4) is room temperature~40℃.