Silicon dioxide surface treating method by precipitation method and use thereof

Abstract

The invention relates to a method for treating the surface of precipitation silicon dioxide and the application of the method. In the circumstance of nitrogen, 70-100 parts of nonreactive polysiloxane (silicon oil) is mixed with compatibilizer which accounts for 8-20% of the weight of the silicon dioxide; 70-100 parts of precipitation silicon dioxide are added in terms of an amount reduced step by step, the time for stirring is 20-60 minutes at each time of precipitation silicon dioxide addition, and then a mixture is obtained and undergoes reaction lasting 3-12 hours at a temperature lower than 130 DEG C; the obtained mixture undergoes vacuuming, wherein, the temperature is 130-160 DEG C and the time is 3-12 hours; and reactive hydroxyl-terminated polysiloxane is added, and then even stirring is carried out; and obtained suspension is ground by a three-roller so as to obtain even suspension of the silicon dioxide and polysiloxane. The invention has the advantages that the silicon dioxide is evenly distributed in the silicon oil, the suspension is good in fluidity, stability is realized in the storage process, and an elastomer has good mechanical property, the use is simple, the method is economical, and easy industrialization can be achieved.

Description

Technical field

[0001] The invention relates to the technical field of silicon dioxide, in particular to a method for surface treatment of precipitated silicon dioxide and its application.

Background technique

[0002] The molecular chain of raw silicone rubber is very soft, and the interaction between bonds is weak. After crosslinking, its strength is very low, and its tensile strength is only a few kg / cm 2 , must be reinforced with reinforcing materials to have available mechanical strength. Microsilica is a commonly used material, and the addition of silica fillers can greatly improve the mechanical properties of silicone rubber.

[0003] There are OH on the surface of silica, which makes it possible to form hydrogen bonds with silicone rubber. On the one hand, this hydrogen bond helps to improve the mechanical properties of silicone rubber; on the other hand, the OH on silica also makes It has poor wettability with silicone rubber, and the viscosity of the rubber i...

Examples

Embodiment 1

[0022] (1) Surface treatment method of precipitated silica

[0023] Add 100 parts of 350cp methylpolysiloxane and 8 parts of hexamethyldisilazane to the stirring tank under nitrogen atmosphere, divide 100 parts of precipitated silica into 6 times and decrease the amount each time The method is to add methyl polysiloxane, and the stirring time is controlled to be 30 minutes each time, and the reaction is carried out at a temperature below 130°C for 10 hours, and then vacuumed at 140°C for 12 hours to remove small molecules, and finally add 100 parts of 50000cp hydroxyl silicone oil, After mixing evenly, it is ground by a three-roll mill to obtain a suspension of silicon dioxide and polysiloxane.

[0024] (2) Application of silica

[0025] Add 17 parts of hydroxy silicone oil with a viscosity of 14000 cp and 8.5 parts of methyl silicone oil with a viscosity of 14000 cp to 100 parts of the suspension of silicon dioxide and polysiloxane prepared above. After 69 reactions, the si...

Embodiment 2

[0029] (1) Surface treatment method of precipitated silica

[0030] Add 100 parts of 350cp methylpolysiloxane and 9 parts of hexamethyldisilazane to the stirring tank under nitrogen atmosphere, and divide 100 parts of precipitated silica into 6 times, each time according to the amount of addition The method is to add to the kettle, control the stirring time for 20 minutes each time, react at 120°C for 10 hours, then vacuumize at 150°C for 12 hours to remove small molecules, then add 100 parts of 50000cp hydroxyl silicone oil, mix and pass Three-roll mill grinding to obtain a suspension of silica and polysiloxane.

[0031] (2) Application of silica

[0032] Add 25 parts of hydroxy silicone oil with a viscosity of 3500 cp, 5 parts of methyl silicone oil of 350 cp and 9 parts of quartz powder to 100 parts of the suspension of silicon dioxide and polysiloxane prepared above, and mix well to obtain the mixture Viscosity and after reacting with vulcanizing agent Catalyst 69F, obta...

Technical field

[0001] The invention relates to the technical field of silicon dioxide, in particular to a method for surface treatment of precipitated silicon dioxide and its application.

Background technique

[0002] The molecular chain of raw silicone rubber is very soft, and the interaction between bonds is weak. After crosslinking, its strength is very low, and its tensile strength is only a few kg / cm 2 , must be reinforced with reinforcing materials to have available mechanical strength. Microsilica is a commonly used material, and the addition of silica fillers can greatly improve the mechanical properties of silicone rubber.

[0003] There are OH on the surface of silica, which makes it possible to form hydrogen bonds with silicone rubber. On the one hand, this hydrogen bond helps to improve the mechanical properties of silicone rubber; on the other hand, the OH on silica also makes It has poor wettability with silicone rubber, and the viscosity of the rubber i...

Examples

Embodiment 1

[0022] (1) Surface treatment method of precipitated silica

[0023] Add 100 parts of 350cp methylpolysiloxane and 8 parts of hexamethyldisilazane to the stirring tank under nitrogen atmosphere, divide 100 parts of precipitated silica into 6 times and decrease the amount each time The method is to add methyl polysiloxane, and the stirring time is controlled to be 30 minutes each time, and the reaction is carried out at a temperature below 130°C for 10 hours, and then vacuumed at 140°C for 12 hours to remove small molecules, and finally add 100 parts of 50000cp hydroxyl silicone oil, After mixing evenly, it is ground by a three-roll mill to obtain a suspension of silicon dioxide and polysiloxane.

[0024] (2) Application of silica

[0025] Add 17 parts of hydroxy silicone oil with a viscosity of 14000 cp and 8.5 parts of methyl silicone oil with a viscosity of 14000 cp to 100 parts of the suspension of silicon dioxide and polysiloxane prepared above. After 69 reactions, the si...

Embodiment 2

[0029] (1) Surface treatment method of precipitated silica

[0030] Add 100 parts of 350cp methylpolysiloxane and 9 parts of hexamethyldisilazane to the stirring tank under nitrogen atmosphere, and divide 100 parts of precipitated silica into 6 times, each time according to the amount of addition The method is to add to the kettle, control the stirring time for 20 minutes each time, react at 120°C for 10 hours, then vacuumize at 150°C for 12 hours to remove small molecules, then add 100 parts of 50000cp hydroxyl silicone oil, mix and pass Three-roll mill grinding to obtain a suspension of silica and polysiloxane.

[0031] (2) Application of silica

[0032] Add 25 parts of hydroxy silicone oil with a viscosity of 3500 cp, 5 parts of methyl silicone oil of 350 cp and 9 parts of quartz powder to 100 parts of the suspension of silicon dioxide and polysiloxane prepared above, and mix well to obtain the mixture Viscosity and after reacting with vulcanizing agent Catalyst 69F, obta...

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