Process for preparing hydrophobic particulate solids containing Si-OH groups and a process for using the same

• US 5,057,151 A
• Filed: 11/24/1989
• Issued: 10/15/1991
• Est. Priority Date: 11/25/1988
• Status: Expired due to Term

• Current Assignee: Wacker-Chemie GmbH (Dr. Alexander Wacker Familiengesellschaft Mit Beschrã¤Nkter Haftung)
• Original Assignee: Wacker-Chemie GmbH (Dr. Alexander Wacker Familiengesellschaft Mit Beschrã¤Nkter Haftung)
• Inventors: Vorbuchner, Helmut, Schuster, Johann, Muller, Horst, Maier, Anton, Pradl, Ferdinand
• Primary Examiner(s): Dixon, Jr., William R.
• Assistant Examiner(s): KLEMANSKI, HELENE G
• Application Number:
  US07/440,831
• Time in Patent Office: 690 Days
• Field of Search: 106/2, 106/287.12, 106/287.15, 523/212, 523/213, 428/405, 427/219
• US Class Current: 106/2
• CPC Class Codes: A61K 6/90 Compositions for taking dental impressions
• CPC Class Codes: C01P 2006/12 Surface area
• CPC Class Codes: C08K 9/06 with silicon-containing compounds
• CPC Class Codes: C08L 83/04 Polysiloxanes
• CPC Class Codes: C09C 1/3081 Treatment with organo-silicon compounds
• CPC Class Codes: C09C 3/12 Treatment with organosilicon compounds C09C3/006 takes precedence
• CPC Class Codes: Y10T 428/2995 Silane, siloxane or silicone coating

Abstract

The invention relates to a process for rendering particulate solids containing Si-OH groups hydrophobic which comprises reacting a water repellent containing an organo-silicon compound with particulate solids containing Si-OH groups with simultaneous mechanical loading of the reaction mixture, in which from 5 to 50 percent by weight of the particulate solids containing Si-OH groups are used, based on the total weight of the reaction mixture containing particulate solids and water repellent, and the use of the resultant hydrophobic particulate solids in compositions containing diorganopolysiloxanes, which can be cured to form elastomers.

Claims

1. A process for rendering a particulate solid containing Si-OH groups hydrophobic which comprises reacting a water repellent containing an organosilicon compound with the particulate solid containing Si-OH groups with simultaneous mechanical loading of the reaction mixture, in which from 5 to 50 percent by weight of the particulate solid containing Si-OH groups are used, based on the total weight of the reaction mixture containing particulate solid and water repellent, and wherein the water repellent contains from 1 to 5 percent by weight of water based on the weight of the water repellent.

2. The process of claim 1, wherein the reaction is carried out in an inert atmosphere and the oxygen content is reduced to a maximum of 3 percent by volume.

3. The process of claim 1, wherein from 20 to 30 percent by weight of the particulate solid containing Si-OH groups are used, based on the total weight of the reaction mixture containing particulate solid and water repellent.

4. The process of claim 2, wherein from 20 to 30 percent by weight of the particulate solid containing Si-OH groups are used, based on the total weight of the particulate solid and water repellent.

5. The process of claim 1, wherein the water repellent comprises from 70 to 89 percent by weight of an organosilicon compound selected from the group consisting of hexamethyldisiloxane, trimethylsilanol and mixtures thereof, from 10 to 30 percent by weight of an organosilicon compound selected from the group consisting of hexamethyldisilazane, divinyltetramethyldisilazane and mixtures thereof, and from 1 to 5 percent by weight of water, where the percent by weight is based on the total weight of the water repellent.

6. The process of claim 2, wherein the water repellent comprises from 70 to 89 percent by weight of an organosilicon compound selected from the group consisting of hexamethyldisiloxane, trimethylsilanol and mixtures thereof, from 10 to 30 percent by weight of an organosilicon compound selected from the group consisting of hexamethyldisilazane, divinyltetramethyldisilazane and mixtures thereof, and from 1 to 5 percent by weight of water, where the percent by weight is based on the total weight of the water repellent.

7. The process of claim 3, wherein the water repellent comprises from 70 to 89 percent by weight of an organosilicon compound selected from the group consisting of hexamethyldisiloxane, trimethylsilanol and mixtures thereof, from 10 to 30 percent by weight of an organosilicon compound selected from the group consisting of hexamethyldisilazane, divinyltetramethyldisilazane and mixtures thereof, and from 1 to 5 percent by weight of water, where the percent by weight is based on the total weight of the water repellent.

8. The process of claim 4, wherein the water repellent comprises from 70 to 89 percent by weight of an organosilicon compound selected from the group consisting of hexamethyldisiloxane, trimethylsilanol and mixtures thereof, from 10 to 30 percent by weight of an organosilicon compound selected from the group consisting of hexamethyldisilazane, divinlytetramethyldisilazane and mixtures thereof, and from 1 to 5 percent by weight of water, where the percent by weight is based on the total weight of the water repellent.

9. A composition containing diorganopolysiloxanes which are curable to form elastomers, and a particulate solid in which at least a part of the particulate solid is obtained by reacting the particulate solid having Si-OH groups with a water repellent containing an organosilicon compound with simultaneous mechanical loading of the reaction mixture, in which from 5 to 50 percent by weight of the particulate solid are used, based on the weight of the reaction mixture containing particulate solid and water repellent, and wherein the water repellent contains from 1 to 5 percent by weight of water based on the weight of the water repellent.