# US 11,028,229 B2 · Method for making an amino-functional polydiorganosiloxane using a removable acid catalyst

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- Number: US 11,028,229 B2
- Document ID: US11028229B2
- Status: Granted
- Kind: B2
- Application number: 16/652,697
- Filed: 2019-04-03
- Published: 2021-03-11
- Granted: 2021-06-08
- Earliest claimed: 2018-05-31
- Assignees: Dow Silicones Corporation
- Applicants: Dow Silicones Corporation
- Inventors: Nisaraporn Suthiwangcharoen; Kimmai Nguyen; Hannah Wedge
- Web page: https://patentgrep.com/patent/US11028229B2

## CPC

- C08G 77/388: containing nitrogen
- C08G 77/08: characterised by the catalysts used
- C08G 77/16: to hydroxy groups
- C08G 77/26: nitrogen-containing groups
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

A method for preparing an amino-functional polydiorganosiloxane employs a removable catalyst. The method differs from previous methods in the selection of catalyst, order of addition of catalyst with respect to other starting materials, and catalyst removal.

## Claims

### Claim 1

A method for preparing an amino-functional polydiorganosiloxane comprising:
1) mixing and heating, at a temperature of 50° C. to 150° C., starting materials comprising
A) a silanol functional polydiorganosiloxane,
B) an aminoalkyl-functional alkoxysilane,
where amounts of starting materials A) and B) are such that a molar excess of silanol groups with respect to alkoxy groups is present, and
C) 0.1% to 0.5%, based on combined weights of all starting materials, of an endblocker having triorganosilyl groups; and thereafter
2) adding starting material D) 0.01% to 5%, based on weight of starting material B), of a carboxylic acid having a boiling temperature of 90° C. to 150° C. and pKa value of 1 to 5; thereby forming a reaction mixture;
3) mixing and heating the reaction mixture to form the reaction product and reduce amount of residual acid in the form of the carboxylic acid and/or carboxylate salt to 0 to <500 ppm, based on the weight of the amino-functional polydiorganosiloxane.

### Claim 2 (depends on 1)

The method of claim 1, where in step 2) the amount of the residual acid is reduced to 0 to <300 ppm, based on the weight of the amino-functional polydiorganosiloxane.

### Claim 3 (depends on 1)

The method of claim 1, where starting material A) is selected from the group consisting of
A1) a silanol end-blocked polydimethylsiloxane with a viscosity of 30 cP to 70 cP at room temperature, and
A2) a silanol end-blocked polydimethylsiloxane with a degree of polymerization of 4 to 8000.

### Claim 4 (depends on 1)

The method of claim 1, where starting material B) is selected from the group consisting of:
B1) 3-aminopropylmethyl dimethoxysilane,
B2) 3-aminopropylmethyl diethoxysilane,
B3) aminoethyl-aminoisobutyl methyl dimethoxy silane,
B4) aminoethyl-aminoisobutyl methyl diethoxysilane
B5) 3-aminopropyldimethyl ethoxysilane,
B6) 3-aminopropyldimethyl methoxysilane,
B7) 3-(2-aminoethylamino)propyl-dimethoxymethylsilane,
B8) 3-(2-aminoethylamino)propyl-diethoxymethylsilane,
B9) aminopropyl methyl dimethoxy silane,
B10) aminopropyl methyl diethoxysilane, and
B11) a combination of two or more of B1) to B10).

### Claim 5 (depends on 1)

The method of claim 1, where starting material C) is selected from the group consisting of:
C1) hexamethyldisilazane,
C2) trimethylmethoxysilane,
C3) trimethylethoxysilane, and
C4) a combination of two or more of C1), C2) and C3).

### Claim 6 (depends on 1)

The method of claim 1, where starting material D) is selected from the group consisting of:
D1) acetic acid,
D2) propionic acid, and
D3) both D1) and D2).

### Claim 7 (depends on 1)

The method of claim 1, where: i) all or a portion of starting material C) is added in step 1), ii) all or a portion of starting material D) is added in step 2), or both i) and ii).

### Claim 8 (depends on 7)

The method of claim 7, where: i) a portion of starting material C) is added in step 1), ii) a portion of starting material D) is added in step 2), or both i) and ii); and the method further comprises iii) adding a second portion of starting material C), iv) adding a second portion of starting material D), or both iii) and iv), in an additional step added to the method after step 2) and before step 3).

### Claim 9 (depends on 7)

The method of claim 7, where all of starting material C) is added in step 1), and all of starting material D) is added in step 2).

### Claim 10 (depends on 1)

The method of claim 1, where starting materials A) and B) are present in amounts such that a molar ratio of silanol groups to respect alkoxy groups is at least 1.1:1.

### Claim 11 (depends on 10)

The method of claim 10, where the molar ratio ranges from 1.2:1 to 2.0:1.

### Claim 12 (depends on 1)

The method of claim 1, where the catalyst is acetic acid or propionic acid, and step 3) is performed by heating the reaction product at a temperature of at least 90° C. at a pressure <100 mmHg for at least 2 hours.

### Claim 13 (depends on 12)

The method of claim 12, where step 3) is performed by heating the reaction product at a temperature of 100° C. to 150° C. at a pressure of 0 to <100 mmHg for 2 to 8 hours.

### Claim 14 (depends on 1)

The method of claim 1, where starting material B) comprises an amino-functional monoalkoxysilane.

### Claim 15 (depends on 1)

The method of claim 1, where the amino-functional polydiorganosiloxane is endcapped with an amino-functional group.

### Claim 16 (depends on 1)

The method of claim 1, the endblocker comprises C1) a monoalkoxysilane, C2) a silazane, or C3) both C1) and C2).

### Claim 17 (depends on 16)

The method of claim 16, the monoalkoxysilane has formula (V): R43SiOR5, where each R4 is independently a monovalent organic group unreactive with silanol functionality and each R5 is independently a monovalent hydrocarbon group of 1 to 6 carbon atoms.

### Claim 18 (depends on 16)

The method of claim 16, the silazane has formula (VI): (R6R72Si)2NH, where each R6 is independently selected from the group consisting of a monovalent hydrocarbon group and a monovalent halogenated hydrocarbon group, each R7 is an independently selected monovalent hydrocarbon group of 1 to 6 carbon atoms.