Hydrophobic precipitated silica for defoamer formulations

US20050192395A1Inactive Publication Date: 2005-09-01EVONIK OPERATIONS GMBH
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  • Hydrophobic precipitated silica for defoamer formulations
  • Hydrophobic precipitated silica for defoamer formulations
  • Hydrophobic precipitated silica for defoamer formulations

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0227] 63 l of deionized water were charged to an 80 l precipitating vessel and heated to 88° C. Added to this initial charge were waterglass (modulus=3.5; density=1.343 g / ml) at a metering rate of 6.5 l / h and sulfuric acid (concentration=7.167 mol / l) with a metering rate of 1.56 l / h, metering taking place so as to maintain a pH of 8.0-8.5 (measured on a sample with a temperature of 60° C.). After 105 minutes the metered feeds are ended. Subsequently the precipitation suspension was acidified to a pH of 3.5 with sulfuric acid (concentration=7.167 mol / l), with the same metering rate as before, and the suspension was then aftertreated in a drying oven at 50° C. for a period of 12 h.

[0228] The suspension was filtered and washed sufficiently with deionized water. The resulting solids content of the filtercake is 15-17%.

[0229] With deionized water introduced initially, and with gentle stirring, the filtercake is liquefied so as to give a silica suspension with a solids content of 6-11%...

example 2

[0272] Both a mineral oil dispersion and a silicone oil dispersion were produced from the product from example 1 and were investigated for defoaming action.

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Abstract

Hydrophobic precipitated silicas with a high pH and low silanol group density, a process for preparing them and their use, particularly in deformer formulations.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to hydrophobic precipitated silicas of high pH and low silanol group density, to a process for preparing them and to their use, such as in defoamers, fillers or carriers. [0003] 2. Description of the Related Art [0004] Hydrophobic precipitated silicas and processes for preparing them are known. Hydrophobicization is accomplished generally by populating the surface of a hydrophilic precipitated silica with suitable organic compounds. Examples of such hydrophobic or partly hydrophobic precipitated silicas are disclosed in patents EP 0 798 348, U.S. Pat. No. 4,377,493 and EP 1 281 735, EP 1 281 733 and EP 1 281 735 disclose hydrophobic precipitated silicas with a pH of 5-9, while WO 2003014020 discloses those having a pH of more than 9.5. [0005] The use of hydrophilic and hydrophobic precipitated silicas in defoamer formulations is likewise known (Pigments Technical Bulletin 42, DEGUSSA, 0...

Claims

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Application Information

Patent Timeline
01 Sep 2005
Publication
US20050192395A1
IPC
B01D19/04; B01J32/00; C01B33/18; C01B33/193; C08K3/34; C08L83/04; C09C1/30
CPC
B01D19/0409; C01B33/18; C01B33/193; C01P2004/61; C01P2006/11; Y10T428/2995; C01P2006/19; C09C1/3018
Inventors
PANZ, CHRISTIAN; ALLERDISSE, RENE