Pulverulent materials
View Patent ↗Pulverulent materials which contain surface-modified and structure-modified pyrogenically prepared metalloid or metallic oxide for the purposes of improvement.
1. Pulverulent materials and mixtures thereof, comprising one or more modified pyrogenically prepared metalloid or metallic oxides having a surface modification and a structure modification wherein the modified pyrogenically prepared metalloid or metallic oxide is
a silanized silica having alkylsilyl groups which are octylsilyl and/or hexadecylsilyl attached to said silica, and having the following physiochemical properties:
BET surface area
25-400 m 2 /g
Average primary particle size
5-50 nm
pH value
3-10
Carbon content
0.1-25%
DBP number %
<200%.
2. The pulverulent materials and mixtures of claim 1 , wherein the surface modification is a chemical modification of the surface of the pyrogenically prepared metalloid or metallic oxide and the structure modification is a physical modification of the physical structure of the pyrogenically prepared metalloid or metallic oxide.
3. The pulverulent materials and mixtures of claim 2 , wherein the physical modification is the result of mechanical action.
4. The pulverulent materials and mixtures of claim 1 , wherein the pyrogenically prepared metalloid or metallic oxide having the structure modification has a DBP number % which is smaller than a pyrogenically prepared metalloid or metallic oxide particle that lacks a structure modification.
5. The pulverulent materials and mixtures of claim 4 , wherein the DBP number is at least 10% smaller than the DBP number % of the pyrogenically prepared metalloid or metallic oxide particle that lacks a structure modification.
6. Method of improving the flowability of pulverulent materials and mixtures thereof, comprising adding to the pulverulent materials and mixtures thereof one or more surface-modified and structure-modified pyrogenically prepared metalloid or metallic oxides wherein the surface-modified and structure-modified pyrogenically prepared metalloid or metallic oxide is
a silanized structure-modified silica having alkylsilyl groups which are octylsilyl and/or hexadecylsilyl attached to said silica, and having the following physiochemical properties:
BET surface area
25-400 m 2 /g
Average primary particle size
5-50 nm
pH value
3-10
Carbon content
0.1-25%
DBP number %
<200%.
7. A composition of matter comprising at least one pulverulent material which is a fire-extinguishing powder and at least one surface-modified pyrogenically prepared metalloid or metallic oxide wherein the surface-modified and structure-modified pyrogenically prepared metalloid or metallic oxide is
a silanized structure-modified silica having alkylsilyl groups which are octylsilyl and/or hexadecylsilyl attached to said silica, and having the following physiochemical properties:
BET surface area
25-400 m 2 /g
Average primary particle size
5-50 nm
pH value
3-10
Carbon content
0.1-25%
DBP number %
<200%.
8. Pulverulent materials and mixtures thereof, comprising one or more silanized silica having alkylsilyl groups which are octylsilyl and/or hexadecylsilyl attached to said silica, and having the following physiochemical properties:
BET surface area
25-400 m 2 /g
Average primary particle size
5-50 nm
pH value
3-10
Carbon content
0.1-25%
DBP number %
<200%.
9. The pulverulent materials and mixtures of claim 8 , wherein the silanized silica has been mechanically modified to result in the DBP number % of <200% which is at least 10% smaller than corresponding silanized silica which has not been mechanically modified.
10. A method of improving the flowability of a pulverulent material which comprises adding the pulverulent materials and mixtures thereof in accordance with claim 8 .
11. A mixture which comprises a fire-extinguishing powder and the pulverulent materials and mixtures in accordance with claim 8 .