A low-extraction silica gel material, a preparation method and application thereof

Abstract

The application belongs to the technical field of silica gel products, and discloses a low-elution silica gel material and a preparation method and application thereof. The low-elution silica gel material is obtained by mixing component A and component B in a mass ratio of 100:(7-26); the component A comprises, in terms of weight fraction, 100 parts of a first base and 0.3-0.8 parts of a platinum gold catalyst; the first base is obtained by graft copolymerization of vinyl-terminated polymethyl silicone oil, vinyl-functionalized cage polysilsesquioxane and surface-hydroxylated nano-oxide in a mass ratio of 100:(5-10):(1-5); and the component B comprises, in terms of weight fraction, 6-18 parts of modified hydrogen-containing MQ silicone resin, 1-8 parts of modified hydrogen-containing silicone oil and 0.05-0.12 parts of an inhibitor. The application constructs a crosslinked network system which is uniform and compact in structure and excellent in stability, and blocks the paths of component migration and molecular chain degradation and elution from the molecular level. The obtained silica gel material has appropriate mechanical strength and use flexibility, and can meet the actual use requirements of food contact products.

Description

Technical Field

[0001] This application belongs to the field of silicone product technology, and specifically relates to a low-exudation silicone material, its preparation method and application. Background Technology

[0002] Infant food contact products need to undergo high-temperature steam sterilization for extended periods during actual use, which places multiple stringent requirements on the materials. They must not only meet domestic and international food contact safety standards to ensure that no harmful substances migrate or leach into the food medium under repeated high-temperature conditions, but also possess suitable hardness, good tensile and tear resistance to withstand long-term biting and use. At the same time, they must maintain molecular structural stability under frequent high-temperature and humid environments, without degradation, yellowing, or mechanical property degradation. In addition, they must be compatible with industrial injection molding, compression molding, and other molding processes, possessing suitable processing viscosity and stable processing characteristics.

[0003] Current silicone rubber materials used in food contact applications still face technical challenges in practical applications, failing to simultaneously meet the aforementioned multiple performance requirements. Existing reinforcing components are mostly dispersed within the matrix through physical blending or weak force bonding, resulting in insufficient interfacial bonding strength. Under repeated high-temperature cooking and humid heat conditions, these reinforcing components are prone to agglomeration, dissociation, and migration. This not only directly leads to excessive total migration but also causes a rapid decline in the material's mechanical properties. Furthermore, the high-filling methods used to improve mechanical properties significantly increase the system viscosity, worsening processing flowability and making them unsuitable for large-scale production. Regarding crosslinking systems, commonly used crosslinking components have simple structures, making them prone to molecular slippage at high temperatures. Some unreacted crosslinking components are easily released, and the uniformity of the crosslinking reaction is difficult to control, easily forming uneven crosslinking networks, further exacerbating the problems of precipitation and performance degradation during use. Summary of the Invention

[0004] This application aims to improve at least one technical problem in the background art.

[0005] The first aspect of this application provides a low-exudation silica gel material, which is obtained by mixing component A and component B in a mass ratio of 100:(7-26); Component A comprises, by weight, 100 parts of the first matrix and 0.3-0.8 parts of platinum catalyst; the first matrix is ​​obtained by graft copolymerization of vinyl-terminated polymethyl silicone oil, vinyl-functionalized cage-type polysilsesquioxane and surface-hydroxylated nano-oxide in a mass ratio of 100:(5-10):(1-5); Component B, by weight, comprises: 6-18 parts of modified hydrogen-containing MQ silicone resin, 1-8 parts of modified hydrogen-containing silicone oil, and 0.05-0.12 parts of inhibitor; the modified hydrogen-containing MQ silicone resin is obtained by grafting epoxy groups onto hydrogen-containing MQ silicone resin; the modified hydrogen-containing silicone oil is obtained by grafting epoxy groups onto hydrogen-containing silicone oil.

[0006] The low-exudation silica gel material provided in this application uses an in-situ graft copolymerization-formed first matrix as the main framework. Through covalent bonding and synergistic crosslinking between specific functional components, a dense and highly stable integrated crosslinked network is constructed, reducing the presence of migratable free components at the molecular level and significantly lowering the risk of exudation during use. The main framework (first matrix) of this silica gel material is formed by graft copolymerization of vinyl-terminated polymethyl silicone oil, vinyl-functionalized cage-like polysilsesquioxane, and surface-hydroxylated nano-oxides. The three components are bonded together by stable chemical bonds, enabling the vinyl-functionalized cage-like polysilsesquioxane and surface-hydroxylated nano-oxides to be uniformly and firmly bonded to the polysiloxane molecular chain. This achieves both efficient reinforcement and avoids the problems of aggregation and migration caused by insufficient bonding force in conventional reinforcing fillers during use. The platinum catalyst provides stable catalysis for the cross-linking reaction of the system. Combined with the synergistic participation of modified hydrogen-containing MQ silicone resin and modified hydrogen-containing silicone oil, the entire system can form a uniform and regular three-dimensional cross-linked structure. The modified hydrogen-containing MQ silicone resin, as the core cross-linking component, provides stable cross-linking nodes for the network structure, improving the overall density and stability of the structure. The modified hydrogen-containing silicone oil is used to adjust the chain segment structure and cross-linking density of the cross-linked network, allowing the silicone material to possess both suitable mechanical strength and toughness. The epoxy groups grafted onto the surfaces of the two types of modified hydrogen-containing components can bind to the active sites within the system, further locking the positions of each functional component. Simultaneously, it consumes residual trace amounts of moisture and active hydroxyl groups in the system, reducing side reactions and preventing the generation of new low-molecular-weight precipitates due to molecular chain degradation and breakage. Overall, this silicone material stably integrates all functional components into the cross-linked network through chemical bonding, without the presence of free fillers, additives, or low-molecular-weight substances. Even under harsh operating conditions such as long-term high-temperature cooking, it maintains structural stability, achieving a core effect of low precipitation while simultaneously ensuring mechanical properties and operational stability.

[0007] Preferably, the viscosity of the vinyl-terminated polymethyl silicone oil is 10000 mPa·s-80000 mPa·s, and the vinyl content in the vinyl-terminated polymethyl silicone oil is 0.06%-0.25% by mass. Optimizing the viscosity and vinyl content of the vinyl-terminated polymethyl silicone oil allows this basic component to better adapt to the overall reaction and processing requirements of the system. A suitable viscosity range ensures good flowability and dispersibility of the material during processing, avoiding the impact of excessively high or low viscosity on the molding effect. Simultaneously, the vinyl content within this preferred range allows for precise reaction matching with the active hydrogen components in the system, ensuring sufficient and uniform cross-linking reaction, forming a complete and stable cross-linked network, reducing free small molecules generated due to incomplete cross-linking, and fundamentally improving the structural stability and low exudation performance of the material.

[0008] Preferably, the vinyl-functionalized cage-like polysilsesquioxane comprises a cage-like silica cubic core structure and vinyl groups connected to the eight vertices of the cage-like silica cubic core structure. By limiting the vinyl-functionalized cage-like polysilsesquioxane to a specific form with a cage-like silica cubic core structure and vinyl groups connected to the eight vertices, the molecular-level reinforcing advantages of this component can be fully utilized. The regular cage-like core structure can achieve uniform dispersion in the system, avoiding agglomeration. The vinyl groups at the vertices can serve as active reaction sites, forming stable covalent bonds with other components in the system. This allows the reinforcing component to be firmly integrated into the main framework of the material, improving the material's mechanical strength and structurally preventing the possibility of free migration of the reinforcing component, further enhancing the material's low-precipitation characteristics.

[0009] Preferably, the hydrogen-containing MQ silicone resin has an M / Q value of 0.6-0.8, a molecular weight of 1000-8000, and a hydrogen content of 0.25%-0.45%; the modified hydrogen-containing MQ silicone resin has an epoxy group content of 0.2%-0.6%. Optimizing the M / Q value, molecular weight, active hydrogen content, and modified epoxy group content of the hydrogen-containing MQ silicone resin allows the core crosslinking component to exert its optimal crosslinking and anchoring effect. A suitable M / Q value and molecular weight ensure the component's own structure is regular and has good compatibility with the matrix. A matched active hydrogen content provides sufficient and stable active sites for the crosslinking reaction, constructing uniform crosslinking nodes. The limited epoxy group content allows for precise reaction with the hydroxyl groups on the surface of the nano-oxide, achieving dual covalent anchoring of the reinforcing component. This ensures sufficient anchoring effect without causing side reactions due to excessive epoxy groups, guaranteeing the stability of the crosslinking system while reducing the risk of precipitation.

[0010] Preferably, the hydrogen content in the hydrogen-containing silicone oil is 0.05%-0.2% by mass; the epoxy content in the modified hydrogen-containing silicone oil is 0.3%-0.8% by mass. Optimizing the active hydrogen content of the hydrogen-containing silicone oil and the modified epoxy content by mass allows the component to precisely exert its chain-extending, tuning, and anti-precipitation effects. A suitable active hydrogen content can effectively regulate the chain segment length and density of the crosslinked network, improving the material's toughness and mechanical stability. A matched epoxy content can fully consume residual trace amounts of moisture and active hydroxyl groups at the molecular chain ends, inhibiting adverse side reactions and blocking the pathway of molecular chain hydrolysis and breakage, preventing the generation of new low-molecular-weight precipitates due to molecular chain degradation. This, in conjunction with the crosslinking component, ensures the long-term stability of the material.

[0011] Preferably, the surface-hydroxylated nano-oxide is obtained by surface hydroxylation of nano-oxide, and the mass content of hydroxyl groups in the surface-hydroxylated nano-oxide is 2%-8%. Controlling the mass content of hydroxyl groups in the surface-hydroxylated nano-oxide within the preferred range ensures that the graft copolymerization reaction between the nano-oxide and the polysiloxane molecular chain proceeds fully. The appropriate hydroxyl content allows the nano-oxide to be stably covalently bonded to the main skeleton of the material through silicon-oxygen bonds. This prevents weak grafting due to insufficient hydroxyl content and side reactions caused by excessive hydroxyl content, thereby improving the binding stability of the nano-reinforcing components from the source and preventing agglomeration and migration under harsh conditions such as high-temperature cooking, thus continuously consolidating the low precipitation and aging resistance of the material.

[0012] Preferably, the nano-oxide includes at least one of nano-titanium dioxide, nano-zinc oxide, and nano-silica.

[0013] Preferably, the particle size of the nano-oxide is 5nm-30nm.

[0014] Preferably, the platinum catalyst contains 3000ppm-5000ppm of platinum.

[0015] Preferably, the inhibitor includes at least one of ethynylcyclohexanol and methylbutynol.

[0016] The second aspect of this application provides a method for preparing the aforementioned low-precipitation silica gel material, comprising the following steps: Component A and component B were mixed and degassed under vacuum to obtain a low-precipitation silica gel material.

[0017] The third aspect of this application provides the application of the aforementioned low-exudation silica material in the manufacture of nipples and baby bottles.

[0018] The beneficial effects of this application are as follows: This application constructs a cross-linked network system with a uniform, dense structure and excellent stability, blocking the pathways of component migration and molecular chain desorption at the molecular level. The resulting silicone material possesses both suitable mechanical strength and toughness, meeting the actual usage requirements of food contact products. It maintains molecular structural stability even under harsh conditions of repeated high-temperature sterilization, with no significant attenuation in mechanical properties and performance characteristics. It also exhibits good processing adaptability, enabling smooth industrial molding production. Overall, it balances low exudation characteristics, mechanical properties, damp heat stability, and scalability, fully meeting the stringent safety and usage requirements of high-end food contact products such as baby nipples and bottles, effectively improving the safety and long-term reliability of silicone materials for food contact applications. Detailed Implementation

[0019] The present application will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Furthermore, it should be understood that after reading the contents of this application, those skilled in the art can make various alterations or modifications to this application, and these equivalent forms also fall within the scope defined by the appended claims.

[0020] Example 1 A low-exudation silica gel material is obtained by mixing component A and component B in a mass ratio of 100:16.

[0021] Component A comprises, by weight, 100 parts of the first matrix and 0.5 parts of platinum catalyst (platinum content 4000 ppm).

[0022] The first matrix is ​​obtained by graft copolymerization of vinyl-terminated polymethyl silicone oil (viscosity of 40000 mPa·s, vinyl content of 0.15%), vinyl-functionalized cage-type polysilsesquioxane, and surface-hydroxylated nano-oxide in a mass ratio of 100:8:3.

[0023] Vinyl-functionalized cage-like polysilsesquioxane comprises a cage-like silicon-oxygen cubic core structure and vinyl groups connected to the eight vertices of the cage-like silicon-oxygen cubic core structure. The preparation method of vinyl-functionalized cage-like polysilsesquioxane includes the following steps: 80 parts of vinyltrimethoxysilane, 20 parts of deionized water, and 30 parts of isopropanol are added to a reaction vessel and stirred until homogeneous. Then, 0.5 parts of hydrochloric acid are added as a catalyst, the temperature is raised to 60°C, and the hydrolysis reaction is maintained at this temperature for 5 hours. Subsequently, the temperature is raised to 85°C, and the condensation reaction is maintained at this temperature for 12 hours. After the reaction is completed, the mixture is neutralized to neutral with sodium hydroxide solution. The solvent, water, and low-molecular-weight byproducts are removed by vacuum distillation. After recrystallization purification, the mixture is dried under vacuum at 100°C for 4 hours to obtain vinyl-functionalized cage-like polysilsesquioxane.

[0024] Surface-hydroxylated nano-oxides are obtained by surface hydroxylation of nano-titanium dioxide (particle size 15 nm), with a hydroxyl content of 5% by mass. The preparation method of surface-hydroxylated nano-oxides includes the following steps: 10 parts of nano-titanium dioxide powder are added to 100 parts of deionized water, ultrasonically dispersed for 30 min to obtain a nano-oxide suspension with a mass fraction of 9%, the pH of the suspension is adjusted to 10 with sodium hydroxide solution, the temperature is raised to 80℃, and the suspension is kept at this temperature and stirred for 3 h for activation. After filtration, the suspension is washed with deionized water until neutral, vacuum dried at 110℃ for 6 h, and then pulverized by air jet milling to obtain surface-hydroxylated nano-oxides.

[0025] The preparation method of the first matrix includes the following steps: 100 parts of vinyl-terminated polymethyl silicone oil, 8 parts of the vinyl-functionalized cage-type polysilsesquioxane prepared above, and 20 parts of isopropanol are added to a reaction vessel and stirred at room temperature for 30 min to mix evenly. 3 parts of surface-hydroxylated nano-oxide are added and stirred for another 30 min to disperse evenly. The temperature is raised to 85°C, and 0.3 parts of food-grade organotin catalyst are added. The reaction is kept at this temperature for 5 h to complete the in-situ graft copolymerization. Subsequently, the system is heated to 150°C, and the organic solvent and low-molecular-weight byproducts are removed by vacuum distillation under a vacuum degree of -0.095 MPa. The temperature is kept at this temperature for 2 h, and the material is discharged at room temperature to obtain the first matrix.

[0026] Component B, by weight, includes: 12 parts of modified hydrogen-containing MQ silicone resin, 4.5 parts of modified hydrogen-containing silicone oil, and 0.08 parts of inhibitor (ethynylcyclohexanol).

[0027] The modified hydrogen-containing MQ silicone resin is obtained by grafting epoxy groups onto hydrogen-containing MQ silicone resin (M / Q value of 0.7, molecular weight of 4500, hydrogen content of 0.35%), with an epoxy group mass content of 0.4%. The preparation method of the modified hydrogen-containing MQ silicone resin includes the following steps: 50 parts of tetraethyl orthosilicate, 28 parts of hexamethyldisiloxane, 12 parts of tetramethyldihydrodisiloxane, and 5 parts of γ-epoxypropoxypropyldimethylmethoxysilane are added to a reaction vessel and stirred evenly. Then, 0.4 parts of sulfuric acid and 15 parts of deionized water are added, the temperature is raised to 65°C, and the reaction is carried out with stirring for 7 hours to complete the co-hydrolysis and condensation reaction. After the reaction, the mixture is neutralized to neutral with sodium carbonate solution, the aqueous phase is removed by separation, the organic phase is washed with water to neutral, the solvent and low molecular weight by-products are removed by vacuum distillation, and the modified hydrogen-containing MQ silicone resin is obtained after filtration.

[0028] Modified hydrogen-containing silicone oil is obtained by grafting epoxy groups onto hydrogen-containing silicone oil (hydrogen content of 0.12% by mass), with the epoxy group content being 0.5% by mass. The preparation method of modified hydrogen-containing silicone oil includes the following steps: adding 100 parts of hydrogen-containing silicone oil, 4 parts of allyl glycidyl ether, and 0.02 parts of platinum catalyst to a reaction vessel, heating to 80℃, maintaining the temperature and stirring for 6 hours, and after the reaction is completed, removing unreacted monomers and low-molecular-weight byproducts by vacuum distillation under a vacuum degree of -0.095MPa, and obtaining modified hydrogen-containing silicone oil after filtration.

[0029] The preparation method of the low-precipitation silica material includes the following steps: mixing component A and component B at room temperature for 20 min (stirring speed of 800 r / min), and degassing under vacuum for 5 min (vacuum degree of -0.095 MPa, room temperature) to obtain the low-precipitation silica material.

[0030] Example 2 A low-exudation silica gel material is obtained by mixing component A and component B in a mass ratio of 100:10.

[0031] Component A comprises, by weight, 100 parts of the first matrix and 0.4 parts of platinum catalyst (platinum content 3000 ppm).

[0032] The first matrix is ​​obtained by graft copolymerization of vinyl-terminated polymethyl silicone oil (viscosity of 20000 mPa·s, vinyl content of 0.10%), vinyl-functionalized cage-type polysilsesquioxane, and surface-hydroxylated nano-oxide in a mass ratio of 100:5:2.

[0033] The vinyl-functionalized cage-like polysilsesquioxane comprises a cage-like silica cubic core structure and vinyl groups connected to the eight vertices of the cage-like silica cubic core structure. The preparation method of the vinyl-functionalized cage-like polysilsesquioxane is the same as in Example 1.

[0034] Surface-hydroxylated nano-oxides are obtained by surface hydroxylation of nano-titanium dioxide (particle size 10 nm), with a hydroxyl content of 3% by mass. The preparation method of surface-hydroxylated nano-oxides includes the following steps: 10 parts of nano-titanium dioxide powder are added to 90 parts of deionized water, ultrasonically dispersed for 25 min to obtain a nano-oxide suspension with a mass fraction of 10%, the pH of the suspension is adjusted to 9 with sodium hydroxide solution, the temperature is raised to 75℃, and the suspension is activated by stirring for 2.5 h. After filtration, the suspension is washed with deionized water until neutral, vacuum dried at 105℃ for 7 h, and then pulverized by air jet milling to obtain surface-hydroxylated nano-oxides.

[0035] The preparation method of the first matrix includes the following steps: 100 parts of vinyl-terminated polymethyl silicone oil, 5 parts of the vinyl-functionalized cage-type polysilsesquioxane prepared above, and 15 parts of isopropanol are added to a reaction vessel and stirred at room temperature for 25 min to mix evenly. 2 parts of surface-hydroxylated nano-oxide are added and stirred for another 25 min to disperse evenly. The temperature is raised to 80°C, and 0.25 parts of food-grade organotin catalyst are added. The reaction is kept at this temperature for 4.5 h to complete the in-situ graft copolymerization. Subsequently, the system is heated to 145°C, and the organic solvent and low-molecular-weight byproducts are removed by vacuum distillation under a vacuum degree of -0.095 MPa. The temperature is kept at this temperature for 1.5 h, and the material is discharged at room temperature to obtain the first matrix.

[0036] Component B, by weight, includes: 8 parts of modified hydrogen-containing MQ silicone resin, 3 parts of modified hydrogen-containing silicone oil, and 0.06 parts of inhibitor (ethynylcyclohexanol).

[0037] The modified hydrogen-containing MQ silicone resin is obtained by grafting epoxy groups onto hydrogen-containing MQ silicone resin (M / Q value of 0.6, molecular weight of 3000, hydrogen content of 0.25%), with an epoxy group mass content of 0.2%. The preparation method of the modified hydrogen-containing MQ silicone resin includes the following steps: 45 parts of tetraethyl orthosilicate, 25 parts of hexamethyldisiloxane, 10 parts of tetramethyldihydrodisiloxane, and 3 parts of γ-epoxypropoxypropyldimethylmethoxysilane are added to a reaction vessel and stirred evenly. Then, 0.3 parts of sulfuric acid and 12 parts of deionized water are added, the temperature is raised to 60°C, and the reaction is carried out with stirring for 6 hours to complete the co-hydrolysis and condensation reaction. After the reaction is completed, the mixture is neutralized to neutral with sodium carbonate solution, the aqueous phase is removed by separation, the organic phase is washed with water to neutral, the solvent and low molecular weight by-products are removed by vacuum distillation, and the modified hydrogen-containing MQ silicone resin is obtained after filtration. Modified hydrogen-containing silicone oil is obtained by grafting epoxy groups onto hydrogen-containing silicone oil (hydrogen content of 0.05% by mass), with the epoxy group content being 0.3% by mass.

[0038] The preparation method of modified hydrogen-containing silicone oil includes the following steps: 100 parts of hydrogen-containing silicone oil, 2.5 parts of allyl glycidyl ether, and 0.015 parts of platinum catalyst are added to a reaction vessel, the temperature is raised to 75°C, and the reaction is carried out with stirring for 5.5 h. After the reaction is completed, the unreacted monomers and low molecular weight byproducts are removed by vacuum distillation under a vacuum degree of -0.095 MPa. After filtration, the modified hydrogen-containing silicone oil is obtained.

[0039] The preparation method of this low-precipitation silica gel material includes the following steps: Component A and component B were stirred at room temperature for 15 min (stirring speed 600 r / min) to mix them, and then vacuum degassed for 4 min (vacuum degree -0.095 MPa, room temperature) to obtain a low-precipitation silica gel material.

[0040] Example 3 A low-exudation silica gel material is obtained by mixing component A and component B in a mass ratio of 100:22.

[0041] Component A comprises, by weight, 100 parts of the first matrix and 0.6 parts of platinum catalyst (platinum content 5000 ppm).

[0042] The first matrix is ​​obtained by graft copolymerization of vinyl-terminated polymethyl silicone oil (viscosity of 60000 mPa·s, vinyl content of 0.20%), vinyl-functionalized cage-type polysilsesquioxane, and surface-hydroxylated nano-oxide in a mass ratio of 100:10:4.

[0043] The vinyl-functionalized cage-like polysilsesquioxane comprises a cage-like silica cubic core structure and vinyl groups connected to the eight vertices of the cage-like silica cubic core structure. The preparation method of the vinyl-functionalized cage-like polysilsesquioxane is the same as in Example 1.

[0044] Surface-hydroxylated nano-oxides are obtained by surface hydroxylation of nano-silica (particle size of 20 nm), with a hydroxyl content of 7% by mass. The preparation method of surface-hydroxylated nano-oxides includes the following steps: 10 parts of nano-silica powder are added to 110 parts of deionized water, ultrasonically dispersed for 35 min to obtain a nano-oxide suspension with a mass fraction of 8%, the pH of the suspension is adjusted to 11 with sodium hydroxide solution, the temperature is raised to 85℃, and the suspension is activated by stirring for 3.5 h. After filtration, the suspension is washed with deionized water until neutral, vacuum dried at 115℃ for 5 h, and then pulverized by air jet milling to obtain surface-hydroxylated nano-oxides.

[0045] The preparation method of the first matrix includes the following steps: 100 parts of vinyl-terminated polymethyl silicone oil, 10 parts of the vinyl-functionalized cage-type polysilsesquioxane prepared above, and 25 parts of isopropanol are added to a reaction vessel and stirred at room temperature for 35 min to mix evenly. 4 parts of surface-hydroxylated nano-oxide are added and stirred for another 35 min to disperse evenly. The temperature is raised to 90°C, and 0.35 parts of food-grade organotin catalyst are added. The reaction is kept at this temperature for 5.5 h to complete the in-situ graft copolymerization. Subsequently, the system is heated to 155°C, and the organic solvent and low-molecular-weight byproducts are removed by vacuum distillation under a vacuum degree of -0.095 MPa. The temperature is kept at this temperature for 2.5 h, and the material is discharged at room temperature to obtain the first matrix.

[0046] Component B, by weight, includes: 16 parts of modified hydrogen-containing MQ silicone resin, 6 parts of modified hydrogen-containing silicone oil, and 0.10 parts of inhibitor (ethynylcyclohexanol).

[0047] The modified hydrogen-containing MQ silicone resin is obtained by grafting epoxy groups onto hydrogen-containing MQ silicone resin (M / Q value of 0.8, molecular weight of 6000, hydrogen content of 0.45%), with an epoxy group mass content of 0.6%. The preparation method of the modified hydrogen-containing MQ silicone resin includes the following steps: 55 parts of tetraethyl orthosilicate, 32 parts of hexamethyldisiloxane, 15 parts of tetramethyldihydrodisiloxane, and 7 parts of γ-epoxypropoxypropyldimethylmethoxysilane are added to a reaction vessel and stirred evenly. Then, 0.5 parts of sulfuric acid and 18 parts of deionized water are added, the temperature is raised to 70°C, and the reaction is carried out by stirring for 8 hours to complete the co-hydrolysis and condensation reaction. After the reaction is completed, the mixture is neutralized to neutral with sodium carbonate solution, the aqueous phase is removed by separation, the organic phase is washed with water to neutral, the solvent and low molecular weight by-products are removed by vacuum distillation, and the modified hydrogen-containing MQ silicone resin is obtained after filtration.

[0048] Modified hydrogen-containing silicone oil is obtained by grafting epoxy groups onto hydrogen-containing silicone oil (hydrogen content of 0.2% by mass), with the epoxy group content being 0.8% by mass. The preparation method of modified hydrogen-containing silicone oil includes the following steps: adding 100 parts of hydrogen-containing silicone oil, 5.5 parts of allyl glycidyl ether, and 0.025 parts of platinum catalyst to a reaction vessel, heating to 85°C, maintaining the temperature and stirring for 6.5 h, and after the reaction is completed, removing unreacted monomers and low-molecular-weight byproducts by vacuum distillation under a vacuum degree of -0.095 MPa, and obtaining modified hydrogen-containing silicone oil after filtration.

[0049] The preparation method of this low-precipitation silica gel material includes the following steps: Component A and component B were stirred at room temperature for 25 minutes (stirring speed 1000 r / min) to mix them, and then vacuum degassed for 6 minutes (vacuum degree -0.095 MPa, room temperature) to obtain a low-precipitation silica gel material.

[0050] Comparative Example 1 A silicone material differs from Example 1 in that: the mass ratio of component A to component B is 100:5; component B contains 3.5 parts of modified hydrogen-containing MQ silicone resin and 1.2 parts of modified hydrogen-containing silicone oil. Everything else is the same as in Example 1.

[0051] Comparative Example 2 A silicone material differs from Example 1 in that: the mass ratio of component A to component B is 100:28; component B contains 20 parts of modified hydrogen-containing MQ silicone resin and 7.5 parts of modified hydrogen-containing silicone oil. Everything else is the same as in Example 1.

[0052] Comparative Example 3 A silicone material differs from Example 1 in that the mass ratio of vinyl-terminated polymethyl silicone oil, vinyl-functionalized cage-like polysilsesquioxane, and surface-hydroxylated nano-oxide in the first matrix is ​​100:3:3. Everything else is the same as in Example 1.

[0053] Comparative Example 4 A silicone material differs from Example 1 in that the mass ratio of vinyl-terminated polymethyl silicone oil, vinyl-functionalized cage-like polysilsesquioxane, and surface-hydroxylated nano-oxide in the first matrix is ​​100:12:3. Everything else is the same as in Example 1.

[0054] Comparative Example 5 A silicone material differs from Example 1 in that the mass ratio of vinyl-terminated polymethyl silicone oil, vinyl-functionalized cage-like polysilsesquioxane, and surface-hydroxylated nano-oxide in the first matrix is ​​100:8:0.5. Everything else is the same as in Example 1.

[0055] Comparative Example 6 A silicone material differs from Example 1 in that the mass ratio of vinyl-terminated polymethyl silicone oil, vinyl-functionalized cage-like polysilsesquioxane, and surface-hydroxylated nano-oxide in the first matrix is ​​100:8:7. Everything else is the same as in Example 1.

[0056] Comparative Example 7 A silicone material, differing from Example 1 in that: component B contains 3 parts of modified hydrogen-containing MQ silicone resin. Everything else is the same as in Example 1.

[0057] Comparative Example 8 A silicone material, differing from Example 1 in that: 20 parts of modified hydrogen-containing MQ silicone resin are used in component B. Everything else is the same as in Example 1.

[0058] Comparative Example 9 A silicone material, differing from Example 1 in that: 0.5 parts of modified hydrogen-containing silicone oil are used in component B. Everything else is the same as in Example 1.

[0059] Comparative Example 10 A silicone material, differing from Example 1 in that: component B contains 10 parts of modified hydrogen-containing silicone oil. Everything else is the same as in Example 1.

[0060] Comparative Example 11 A silicone material, differing from Example 1 in that the first matrix does not contain vinyl-functionalized cage-like polysilsesquioxane. Otherwise, it is the same as Example 1.

[0061] Comparative Example 12 A silicone material, differing from Example 1 in that the first matrix does not contain hydroxylated nano-oxides. Otherwise, it is the same as Example 1.

[0062] Comparative Example 13 A silicone material, differing from Example 1 in that component B does not contain MQ silicone resin. Otherwise, it is the same as Example 1.

[0063] Comparative Example 14 A silicone material, differing from Example 1 in that component B does not contain modified hydrogen-containing silicone oil. Otherwise, it is the same as Example 1.

[0064] The following performance tests were performed on the silicone materials obtained in Examples 1-3 and Comparative Examples 1-14: Shore hardness A: determined according to GB / T 39693.4-2025; Tensile strength: tested according to GB / T 528-2009; Tear strength: Tested according to GB / T 529-2008; Total migration: According to GB 4806.7-2023, it was steamed at 121℃ for 30 times.

[0065] The test results are shown in Table 1.

[0066] Table 1 Based on the data in Table 1, compared with the examples, the amount of curing-related components added in Comparative Example 1 was relatively small. This made it difficult to form sufficient and stable cross-linking sites within the system, resulting in a looser cross-linking network structure. This not only significantly reduced the mechanical strength of the material, but also made it more prone to migration of unfixed small molecules under the humid heat of high-temperature cooking. The molecular chain structure also tended to loosen, leading to a significant decrease in the retention of mechanical properties. Overall, the performance was far inferior to that of the examples. In Comparative Example 2, the amount of curing-related components added was excessive, resulting in an excessively high cross-linking density. The material was generally harder and its toughness was significantly reduced, with a marked decrease in tear resistance. Furthermore, the excessive cross-linking components could not fully participate in the reaction, and the remaining portion easily migrated outwards under humid heat, increasing the total migration amount. The performance retention after cooking was also far inferior to that of the examples. In Comparative Example 3, the amount of vinyl-functionalized cage-like polysilsesquioxane added was too small, failing to form a sufficient molecular-level reinforcing structure within the system. The material's mechanical support was insufficient, and the covalent bonding provided by this component was weak, making it difficult to effectively inhibit component migration. After high-temperature cooking, the mechanical properties deteriorated significantly, and the risk of precipitation was significantly higher than in the examples. In Comparative Example 4, the amount of vinyl-functionalized cage-like polysilsesquioxane added was excessive, exceeding the system's compatibility equilibrium range. This not only failed to further improve the reinforcing effect but also caused uneven component dispersion, disrupting the regularity of the cross-linked network, resulting in decreased material toughness and increased migration. The overall performance stability was inferior to the examples. In Comparative Example 5, the amount of surface-hydroxylated nano-oxide added was insufficient, making it difficult to form a sufficient covalent anchoring effect with the matrix resin. The binding stability of the reinforcing particles within the system was insufficient, and dissociation and migration were prone to occur under high-temperature and humid conditions. Not only were the mechanical properties weaker, but the total migration was also significantly higher than in the examples. In Comparative Example 6, the excessive addition of surface-hydroxylated nano-oxides easily leads to agglomeration within the system, disrupting the uniformity of the cross-linking network and causing fluctuations in the material's mechanical properties. Furthermore, the agglomerated particles form channels for small molecule migration, significantly increasing the total migration amount and resulting in significantly worse cooking resistance compared to the examples. In Comparative Example 7, the insufficient addition of modified hydrogen-containing MQ silicone resin resulted in a lack of sufficient three-dimensional cross-linking nodes, leading to a loose and unstable cross-linking network structure. This significantly reduced the material's mechanical strength, making it susceptible to molecular structure damage under humid and hot conditions, greatly increasing the risk of small molecule migration, and resulting in overall performance far inferior to the examples. In Comparative Example 8, the excessive addition of modified hydrogen-containing MQ silicone resin caused over-cross-linking, resulting in high material hardness and insufficient toughness, significantly reduced tear resistance, and the excess resin component failing to fully participate in the cross-linking reaction. The remaining portion easily migrates during cooking, resulting in overall performance inferior to the examples. In Comparative Example 9, the amount of modified hydrogen-containing silicone oil added was too small, which could not effectively adjust the chain segment structure of the cross-linked network. As a result, the toughness and overall compatibility of the material deteriorated, the density of the cross-linked network was uneven, the mechanical properties deteriorated significantly after high-temperature cooking, and the risk of precipitation also increased. There was a significant difference from the stable performance of the examples.In Comparative Example 10, the excessive addition of modified hydrogen-containing silicone oil disrupted the balanced structure of the crosslinking network, resulting in insufficient crosslinking, lower material strength, and a softer texture. The excess silicone oil component was difficult to fix within the network structure and easily precipitated out under humid and hot conditions, with both the total migration and performance degradation significantly exceeding those of the examples. In Comparative Example 11, the absence of vinyl-functionalized cage-like polysilsesquioxane meant the system lacked a core molecular-level covalent reinforcing structure, leading to a significant decrease in mechanical properties and a marked weakening of the bonding force between components. Under high-temperature cooking, component migration was extremely pronounced, with a substantial increase in total migration, failing to meet the core requirement of low precipitation. In Comparative Example 12, the lack of surface-hydroxylated nano-oxides resulted in a deficiency of covalently anchored reinforcing units, leading to insufficient overall structural stability. The molecular chains were prone to loosening and degradation under humid and hot conditions, resulting not only in weaker mechanical properties but also the generation of more low-molecular-weight degradation products, with a precipitation risk far exceeding that of the examples. In Comparative Example 13, no modified hydrogen-containing MQ silicone resin was added. The system lacked core three-dimensional cross-linking nodes, and a complete cross-linking network could not be effectively constructed. The material's mechanical strength was extremely low, failing to meet basic usage requirements. Furthermore, a large number of unfixed components migrated rapidly during cooking, resulting in a high total migration rate and extremely poor performance. In Comparative Example 14, no modified hydrogen-containing silicone oil was added, making it impossible to effectively tune the cross-linking network. The network structure was too dense and lacked toughness, significantly reducing the material's tensile and tear resistance. The molecular structure was easily damaged after high-temperature cooking, resulting in low mechanical property retention and a significantly higher risk of precipitation than in the examples.

[0067] The residual volatile methylcyclosiloxanes of the first matrix and low-precipitation silica gel material prepared in Example 1 were tested according to GB / T 28112-2011 using an Agilent 8890 GC chromatogram equipped with an FID detector and an autosampler 7693A; an Hp-5 column (30m × 0.32mm × 0.25μm) was used, and high-purity nitrogen (99.999% purity) was used as the carrier gas. The test results are shown in Table 2.

[0068] Table 2 As shown in Table 2, the residual amount of methylcyclosiloxane in the first matrix used in this application and the final low-precipitation silicone material is at a low level, which effectively controls the content of vinyl silicone oil cyclic residues, meets the environmental protection requirements of low volatility and low VOC, and complies with international and national standards for food contact and high-end environmentally friendly silicone products.

[0069] In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature.

[0070] The above description is only a preferred embodiment of this application. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of this application, and these improvements and additions should also be considered within the scope of protection of this application.

Claims

1. A low-exudation silica gel material, characterized in that, It is obtained by mixing component A and component B in a mass ratio of 100:(7-26); Component A comprises, by weight, 100 parts of the first matrix and 0.3-0.8 parts of the platinum catalyst; the first matrix is ​​obtained by graft copolymerization of vinyl-terminated polymethyl silicone oil, vinyl-functionalized cage-type polysilsesquioxane and surface-hydroxylated nano-oxide in a mass ratio of 100:(5-10):(1-5). Component B, by weight, comprises: 6-18 parts of modified hydrogen-containing MQ silicone resin, 1-8 parts of modified hydrogen-containing silicone oil, and 0.05-0.12 parts of inhibitor; the modified hydrogen-containing MQ silicone resin is obtained by grafting epoxy groups onto hydrogen-containing MQ silicone resin; the modified hydrogen-containing silicone oil is obtained by grafting epoxy groups onto hydrogen-containing silicone oil.

2. The low-exudation silica gel material according to claim 1, characterized in that, The viscosity of the vinyl-terminated polymethyl silicone oil is 10000 mPa·s-80000 mPa·s, and the mass content of vinyl in the vinyl-terminated polymethyl silicone oil is 0.06%-0.25%.

3. The low-exudation silica gel material according to claim 1, characterized in that, The vinyl-functionalized cage-like polysilsesquioxane comprises a cage-like silicon-oxygen cubic core structure and vinyl groups respectively connected to the eight vertices of the cage-like silicon-oxygen cubic core structure.

4. The low-exudation silica gel material according to claim 1, characterized in that, The hydrogen-containing MQ silicone resin has an M / Q value of 0.6-0.8, a molecular weight of 1000-8000, and a hydrogen content of 0.25%-0.45%; the modified hydrogen-containing MQ silicone resin has an epoxy group content of 0.2%-0.6% by mass.

5. The low-exudation silica gel material according to claim 1, characterized in that, The hydrogen content in the hydrogen-containing silicone oil is 0.05%-0.2% by mass; the epoxy content in the modified hydrogen-containing silicone oil is 0.3%-0.8% by mass.

6. The low-exudation silica gel material according to claim 1, characterized in that, The surface-hydroxylated nano-oxide is obtained by surface hydroxylation of nano-oxide, and the mass content of hydroxyl groups in the surface-hydroxylated nano-oxide is 2%-8%.

7. The low-exudation silica gel material according to claim 6, characterized in that, The nano-oxides include at least one of nano-titanium dioxide, nano-zinc oxide, and nano-silicon dioxide; And / or, the particle size of the nano-oxide is 5nm-30nm.

8. The low-exudation silica gel material according to claim 1, characterized in that, The platinum catalyst contains 3000ppm-5000ppm of platinum. And / or, the inhibitor includes at least one of ethynylcyclohexanol and methylbutynol.

9. The method for preparing the low-precipitation silica gel material according to any one of claims 1-8, characterized in that, Includes the following steps: The components A and B are mixed and then degassed under vacuum to obtain the low-precipitation silica gel material.

10. The use of the low-exudation silica gel material as described in any one of claims 1-8 in the manufacture of nipples and baby bottles.

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