Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Chemically assisted milling of silicas

A technology of silica and chemical reagents, applied in the direction of silica, silica, inorganic chemistry, etc., can solve the problems of unstable and complex porous particle dispersion

Inactive Publication Date: 2007-07-25
WR GRACE & CO
View PDF30 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, porous particle dispersions are generally unstable
To complicate matters, most coating applications require dispersions of more than 20% solids

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Chemically assisted milling of silicas
  • Chemically assisted milling of silicas
  • Chemically assisted milling of silicas

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0087] Preparation of Submicron Surface Modified Silica Gels

[0088] This example illustrates the preparation of a high solids content, low viscosity dispersion by wet milling a silica gel material in the presence of a surface modifier. First, by adding an appropriate amount of NaAlO to deionized water 2 Preparation of NaAlO 23% w / w solution of surface modifier (from EM Scientific). The parent silica slurry was then prepared in the following proportions: 410 g of 3 wt % NaAlO 2 The solution was added to 1230 g of deionized water. To this solution was added 2731 g (aqueous basis: 45% solids) of Syloid TM W500. For these ratios, the surface modifier (Al 2 o 3 ) at a concentration of 1% (w / w SiO 2 ). Syloid measured by nitrogen porosimetry after vacuum activation (removal of pore water) TM W500 has a pore volume of 1.20cm 3 / g. This suspension was then wet milled using a Netzsch LabStar media mill and 0.4-0.7 mm SEPR media at a flow rate of approximately 0.7 L / min ...

Embodiment 2

[0097] Preparation of submicron surface-modified silica from fumed silica

[0098] This example illustrates the preparation of high solids, low viscosity dispersions by wet milling fumed silica materials in the presence of surface modifiers. Add 21.4g NaAlO to 3269g deionized water 2 Surface modifier (from EM Scientific). A precursor silica slurry was then prepared by adding 1116.4 g of Degussa Aerosil A200. For these ratios, the surface modifier (Al 2 o 3 ) at a concentration of 2% (w / w SiO 2 ). This suspension was then wet milled using a Netzsch LabStar media mill and 0.4-0.7 mm SEPR media at a flow rate of about 0.7 L / min for a total time of 200 min. After milling, the pH of the dispersion was 7.8, the median particle size (D50) was 0.16 microns, and the dispersion solids content was 24.6%. A portion of the dispersion was dried and the pore volume of the dried dispersion measured by nitrogen porosimetry was 0.90 cm 3 / g. A plot of viscosity versus solids content fo...

Embodiment 3a

[0114] Preparation of Coating Formulations Including Surface-Modified Silicas of the Invention

[0115] Coating formulations consisting of silica and binder were prepared by mixing the materials in the following proportions. 250 g of a surface-modified silica gel prepared according to Example 1 with a solids content of 30.0 wt % was mixed with 161 g of a 15.5 wt % solution of polyvinyl alcohol (CelVol 523 from Celanese) and 175 g of deionized water. This mixture had a total solids content of 17.1% by weight and a silica:PVOH ratio of 3:1 on a solids basis. The mixture was coated on a plastic PET film (Mellinex 534 from ICI) and dried at 130C for 1 min. The final coating weight is 20.1g / m 2 . The test charts were printed onto the coated sheets using a commercially available narrow format inkjet printer (EPSONC80; EPSON880; Hewlett-Packard-970; EPSON870). The uniformity of the unprinted coating was recorded and a rating of 1-4 was given for the appearance of the printed test...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
particle sizeaaaaaaaaaa
porosityaaaaaaaaaa
particle sizeaaaaaaaaaa
Login to View More

Abstract

The present invention relates to a dispersion of porous surface modified silica particles including fluid and the porous particles, wherein the maximum fractional occupied volume (Fmax) of the particles in the dispersion is at least about 0.55 as determined from the relationship (I) wherein F is the fractional occupied volume of the solids in the fluid, Fmax is the asymptotic limit (maximum) of fractional occupied volume as the viscosity approaches infinity, b is the intrinsic viscosity, no is the viscosity of the fluid and n is the viscosity of the dispersion.

Description

Background of the invention [0001] The present invention relates to stable dispersions of porous inorganic oxide particles having a high solids content. The invention also relates to processes for preparing these dispersions. [0002] Finely divided inorganic oxide particles are well known. For example, "colloidal silica" is well known and generally has a median particle size (diameter) of 0.1 micron (100 nanometers) or less. See, eg, Canadian Patents 609186 and 609190; and US Patent 3012973. Colloidal silica in its dispersed, non-aggregated state is not porous, and any surface area present in these particles is on the outer surfaces of the primary non-aggregated particles, ie, no surface area provided by internal pores in the particles. [0003] Dispersions of smaller silica particles known as "silica microgels" are disclosed in US Patent 4,954,220. Silica microgel particle dispersions are prepared by reacting an alkali metal silicate and an acid under conditions that ind...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/141C09D7/62
CPCC08K3/36C08K7/26C09D7/1225C01B33/149C01P2006/22C09D7/1283C09D7/1266C01B33/1417C09D7/1275C09D7/62C09D7/67C09D7/68C09D7/69C01B33/141C01B33/14
Inventor D·M·查普曼
Owner WR GRACE & CO
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com