A kind of preparation method of alkoxy-terminated polydimethylsiloxane

Abstract

The invention belongs to the field of organic silicon polymers and in particular relates to a preparation method of alkoxy-terminated polydimethylsiloxane. Compared with an existing alkoxy terminationmethod, the preparation method of the alkoxy-terminated polydimethylsiloxane, provided by the invention, has the following technical effects that in step (1), the initial temperature (35 to 85 DEG C)is relatively low, reaction conditions are moderate and pressurizing or decompression operation is not needed; the total reaction time of the provided preparation method is less than 3h and the operation of all steps are simple and moderate to operate, so that safety production is facilitated, and efficient production of an alkoxy-terminated polydimethylsiloxane product is also realized at the same time; one of dimethylamine, diethylamine, dipropylamine, methyl ethylamine and pyrrolidine is used as a catalyst; the termination rate of the prepared alkoxy-terminated polydimethylsiloxane is high; the catalyst can be recycled and repeatedly utilized through a decompression distillation and rectification manner.

Description

technical field

[0001] The invention belongs to the field of organosilicon polymers, in particular to a preparation method of alkoxy-terminated polydimethylsiloxane. Background technique

[0002] Due to its superior weather resistance, extremely wide elastic temperature range, excellent flame retardancy and high cost performance, room temperature vulcanized silicone rubber is widely used in structural assembly and non-structural assembly joint sealing of exterior walls of construction projects, and Various waterproof seals for interior decoration.

[0003] At present, RTV silicone rubber on the market is mainly divided into three types: deacidification type, deketoxime type and dealcoholization type. During the vulcanization process, acetic acid, butanone oxime and alcohols are removed respectively. Acetic acid has strong biological irritation, butanone oxime has certain biological toxicity, and alcohols show better biological friendliness. Therefore, the amount of dealcoho...

Examples

Embodiment 1

[0029] According to the molar ratio of 1:2.1:5, respectively weigh the hydroxyl-terminated polydimethylsiloxane and methyl orthosilicate (Si(OCH 3 ) 4 ) and dimethylamine, added to the reactor, and reacted at 35°C for 60 minutes; then depressurized to -0.05 MPa and heated to 90°C, and continued to react for 30 minutes; then depressurized to -0.1 MPa and heated to 110°C , and continue the reaction to remove the low boiling for 60 minutes to obtain the product alkoxy-terminated polydimethylsiloxane.

[0030] Detect the prepared alkoxypolydimethylsiloxane: take a certain amount of the product alkoxy-terminated polydimethylsiloxane, add tetrabutyl titanate with a mass content of 1.5%, and pass through the flow The viscosity change of the polydimethylsiloxane before and after the reaction is measured by a variable instrument is less than 10%, indicating that the capping ratio is greater than 85%, which meets the requirements for the preparation of alcohol-type sealant with a long ...

Embodiment 2

[0033] According to the molar ratio of 1: 2.2: 5, respectively weigh the hydroxyl-terminated polydimethylsiloxane and tetraethyl orthosilicate (Si(OC 2 h 5 ) 4 ) and diethylamine, added to the reactor, and reacted at 50°C for 50 minutes; then depressurized to -0.05 MPa and heated to 90°C, and continued to react for 25 minutes; then depressurized to -0.1 MPa and heated to 110°C , and continue the reaction to remove the low boiling point for 75 minutes to obtain the product alkoxy-terminated polydimethylsiloxane.

[0034] Detect the prepared alkoxypolydimethylsiloxane: take a certain amount of the product alkoxy-terminated polydimethylsiloxane, add tetrabutyl titanate with a mass content of 1.5%, and pass through the flow The viscosity change of the polydimethylsiloxane before and after the reaction is measured by a variable instrument is less than 10%, indicating that the capping ratio is greater than 85%, which meets the requirements for the preparation of alcohol-type seala...

Embodiment 3

[0037] According to the molar ratio of 1:2.3:5, respectively weigh the hydroxyl-terminated polydimethylsiloxane and orthophenylsilicate (Si(OC 5 h 6 ) 4 ) and pyrrolidine were added to the reactor, and reacted at 85°C for 30 minutes; then depressurized to -0.05 MPa and heated to 110°C, and continued to react for 15 minutes; then depressurized to -0.1 MPa and heated to 120°C, Continue the reaction to remove the low boiling point for 90 minutes to obtain the product alkoxy-terminated polydimethylsiloxane.

[0038] Detect the prepared alkoxypolydimethylsiloxane: take a certain amount of the product alkoxy-terminated polydimethylsiloxane, add tetrabutyl titanate with a mass content of 1.5%, and pass through the flow The viscosity change of the polydimethylsiloxane before and after the reaction is measured by a variable instrument is less than 10%, indicating that the capping ratio is greater than 85%, which meets the requirements for the preparation of alcohol-type sealant with ...

technical field

[0001] The invention belongs to the field of organosilicon polymers, in particular to a preparation method of alkoxy-terminated polydimethylsiloxane. Background technique

[0002] Due to its superior weather resistance, extremely wide elastic temperature range, excellent flame retardancy and high cost performance, room temperature vulcanized silicone rubber is widely used in structural assembly and non-structural assembly joint sealing of exterior walls of construction projects, and Various waterproof seals for interior decoration.

[0003] At present, RTV silicone rubber on the market is mainly divided into three types: deacidification type, deketoxime type and dealcoholization type. During the vulcanization process, acetic acid, butanone oxime and alcohols are removed respectively. Acetic acid has strong biological irritation, butanone oxime has certain biological toxicity, and alcohols show better biological friendliness. Therefore, the amount of dealcoho...

Examples

Embodiment 1

[0029] According to the molar ratio of 1:2.1:5, respectively weigh the hydroxyl-terminated polydimethylsiloxane and methyl orthosilicate (Si(OCH 3 ) 4 ) and dimethylamine, added to the reactor, and reacted at 35°C for 60 minutes; then depressurized to -0.05 MPa and heated to 90°C, and continued to react for 30 minutes; then depressurized to -0.1 MPa and heated to 110°C , and continue the reaction to remove the low boiling for 60 minutes to obtain the product alkoxy-terminated polydimethylsiloxane.

[0030] Detect the prepared alkoxypolydimethylsiloxane: take a certain amount of the product alkoxy-terminated polydimethylsiloxane, add tetrabutyl titanate with a mass content of 1.5%, and pass through the flow The viscosity change of the polydimethylsiloxane before and after the reaction is measured by a variable instrument is less than 10%, indicating that the capping ratio is greater than 85%, which meets the requirements for the preparation of alcohol-type sealant with a long ...

Embodiment 2

[0033] According to the molar ratio of 1: 2.2: 5, respectively weigh the hydroxyl-terminated polydimethylsiloxane and tetraethyl orthosilicate (Si(OC 2 h 5 ) 4 ) and diethylamine, added to the reactor, and reacted at 50°C for 50 minutes; then depressurized to -0.05 MPa and heated to 90°C, and continued to react for 25 minutes; then depressurized to -0.1 MPa and heated to 110°C , and continue the reaction to remove the low boiling point for 75 minutes to obtain the product alkoxy-terminated polydimethylsiloxane.

[0034] Detect the prepared alkoxypolydimethylsiloxane: take a certain amount of the product alkoxy-terminated polydimethylsiloxane, add tetrabutyl titanate with a mass content of 1.5%, and pass through the flow The viscosity change of the polydimethylsiloxane before and after the reaction is measured by a variable instrument is less than 10%, indicating that the capping ratio is greater than 85%, which meets the requirements for the preparation of alcohol-type seala...

Embodiment 3

[0037] According to the molar ratio of 1:2.3:5, respectively weigh the hydroxyl-terminated polydimethylsiloxane and orthophenylsilicate (Si(OC 5 h 6 ) 4 ) and pyrrolidine were added to the reactor, and reacted at 85°C for 30 minutes; then depressurized to -0.05 MPa and heated to 110°C, and continued to react for 15 minutes; then depressurized to -0.1 MPa and heated to 120°C, Continue the reaction to remove the low boiling point for 90 minutes to obtain the product alkoxy-terminated polydimethylsiloxane.

[0038] Detect the prepared alkoxypolydimethylsiloxane: take a certain amount of the product alkoxy-terminated polydimethylsiloxane, add tetrabutyl titanate with a mass content of 1.5%, and pass through the flow The viscosity change of the polydimethylsiloxane before and after the reaction is measured by a variable instrument is less than 10%, indicating that the capping ratio is greater than 85%, which meets the requirements for the preparation of alcohol-type sealant with ...