Preparation method for synthesizing polysiloxane neutralizing agent by using alkaline process

Abstract

The invention relates to a preparation method for synthesizing a polysiloxane neutralizing agent, and particularly relates to the preparation method for synthesizing the polysiloxane neutralizing agent by using an alkaline process. The neutralizing agent can be used for neutralizing dimethyl siloxane different in viscosity. The preparation method comprises the following detailed steps: adding phosphoric acid and hydroxyl blocked siloxane which has dimethyl siloxane links into a reaction container, stirring and heating, controlling the temperature and dehydrating until the mixture is transparent, wherein silicon-based phosphate with different viscosities can be prepared by regulating the dehydration time. The silicon-based phosphate is used as the neutralizing agent for alkaline-process polymerization, and the neutralization time is shortened by 65%-95% in comparison with the conventional neutralization time; moreover, the preparation method is simple in preparation process, convenient to operate and easy to popularize and industrialize, also has an excellent neutralization effect and can be used for remarkably improving the thermal stability of polysiloxane.

Description

technical field

[0001] The invention relates to the field of organosilicon, in particular to a method for preparing a polysiloxane neutralizing agent, in particular to a method for preparing a polysiloxane neutralizing agent synthesized by an alkali method, and the neutralizing agent can be used to neutralize different viscosities Methylsiloxane. Background technique

[0002] In 1949, Corning Glass Company of the United States invented the method of polymerizing cyclic or short-chain linear polysiloxanes into high molecular polysiloxanes under the catalysis of basic catalysts. This method is widely used in the synthesis of various polysiloxanes. Commonly used basic catalysts include: sodium hydroxide, potassium hydroxide, cesium hydroxide and lithium hydroxide, and temporary catalysts tetramethylammonium hydroxide, tetra-n-butylphosphorous hydroxide and their silicon alkoxides. Temporary catalysts can be deactivated by thermal decomposition after polymerization, while alkal...

Examples

Embodiment 1

[0027] Add 100 parts of phosphoric acid with a mass fraction of 88% and 900 parts of hydroxyl-terminated linear products in the flask, start stirring and heat up at a stirring speed of 220rpm, control the temperature at 110°C to dehydrate until transparent, and dehydrate for 12 minutes to obtain silicon-based phosphoric acid Esters, the viscosity of silicon-based phosphate was measured with a Brookfield viscometer.

[0028] The prepared silicon-based phosphate was neutralized with dimethylsiloxane, and the time required for neutralization was recorded, and 10 mg of dimethylsiloxane was weighed for thermogravimetric testing.

Embodiment 2

[0030] Add 10 parts of phosphoric acid with a mass fraction of 85% and 110 parts of hydroxyl-terminated linear products in the flask, start stirring and heat up at a stirring speed of 200 rpm, control the temperature at 100°C to dehydrate until transparent, and dehydrate for 20 minutes to obtain silyl phosphoric acid Esters, the viscosity of silicon-based phosphate was measured with a Brookfield viscometer.

[0031] The prepared silicon-based phosphate was neutralized with dimethylsiloxane, and the time required for neutralization was recorded, and 10 mg of dimethylsiloxane was weighed for thermogravimetric testing.

Embodiment 3

[0033] Add 100 parts of phosphoric acid with a mass fraction of 98% and 600 parts of hydroxyl-terminated linear products in the flask, start stirring to raise the temperature, the stirring speed is 250rpm, control the temperature at 120°C to dehydrate until transparent, and the dehydration time is 8 minutes to prepare silicon-based phosphoric acid Esters, the viscosity of silicon-based phosphate was measured with a Brookfield viscometer.

[0034] The prepared silicon-based phosphate was neutralized with dimethylsiloxane, and the time required for neutralization was recorded, and 10 mg of dimethylsiloxane was weighed for thermogravimetric testing.

technical field

[0001] The invention relates to the field of organosilicon, in particular to a method for preparing a polysiloxane neutralizing agent, in particular to a method for preparing a polysiloxane neutralizing agent synthesized by an alkali method, and the neutralizing agent can be used to neutralize different viscosities Methylsiloxane. Background technique

[0002] In 1949, Corning Glass Company of the United States invented the method of polymerizing cyclic or short-chain linear polysiloxanes into high molecular polysiloxanes under the catalysis of basic catalysts. This method is widely used in the synthesis of various polysiloxanes. Commonly used basic catalysts include: sodium hydroxide, potassium hydroxide, cesium hydroxide and lithium hydroxide, and temporary catalysts tetramethylammonium hydroxide, tetra-n-butylphosphorous hydroxide and their silicon alkoxides. Temporary catalysts can be deactivated by thermal decomposition after polymerization, while alkal...

Examples

Embodiment 1

[0027] Add 100 parts of phosphoric acid with a mass fraction of 88% and 900 parts of hydroxyl-terminated linear products in the flask, start stirring and heat up at a stirring speed of 220rpm, control the temperature at 110°C to dehydrate until transparent, and dehydrate for 12 minutes to obtain silicon-based phosphoric acid Esters, the viscosity of silicon-based phosphate was measured with a Brookfield viscometer.

[0028] The prepared silicon-based phosphate was neutralized with dimethylsiloxane, and the time required for neutralization was recorded, and 10 mg of dimethylsiloxane was weighed for thermogravimetric testing.

Embodiment 2

[0030] Add 10 parts of phosphoric acid with a mass fraction of 85% and 110 parts of hydroxyl-terminated linear products in the flask, start stirring and heat up at a stirring speed of 200 rpm, control the temperature at 100°C to dehydrate until transparent, and dehydrate for 20 minutes to obtain silyl phosphoric acid Esters, the viscosity of silicon-based phosphate was measured with a Brookfield viscometer.

[0031] The prepared silicon-based phosphate was neutralized with dimethylsiloxane, and the time required for neutralization was recorded, and 10 mg of dimethylsiloxane was weighed for thermogravimetric testing.

Embodiment 3

[0033] Add 100 parts of phosphoric acid with a mass fraction of 98% and 600 parts of hydroxyl-terminated linear products in the flask, start stirring to raise the temperature, the stirring speed is 250rpm, control the temperature at 120°C to dehydrate until transparent, and the dehydration time is 8 minutes to prepare silicon-based phosphoric acid Esters, the viscosity of silicon-based phosphate was measured with a Brookfield viscometer.

[0034] The prepared silicon-based phosphate was neutralized with dimethylsiloxane, and the time required for neutralization was recorded, and 10 mg of dimethylsiloxane was weighed for thermogravimetric testing.

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