Hydrophobic Colloidal Silica

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Product Details

Category

Anticaking Agents; Emulsion Stabilizer; Glidant; Suspending Agents; Stabilizer; Viscosity-increasing Agents

Molecular Weight

60.08

Grade

Pharmceutical Excipients

Description

Hydrophobic colloidal silica occurs as a light, fine, white or almost white amorphous powder, not wettable by water.

UNII

NA

Chemical Name

Silane, dichloro-dimethyl-, reaction products with silica

CAS Number

-44-9

Synonyms

Aerosil R972; silica dimethyl silylate; silica hydrophobica colloidalis; silicic acid, silylated; silicon dioxide, silanated

Administration route

Oral ; rectal

Dosage Form

If you want to learn more, please visit our website Hebei Silicon Research Electronic Materials Co., L.

Oral tablets; rectal suppositories

Stability and Storage Conditions

Hydrophobic colloidal silica should be stored in a well-closed container. It will not absorb moisture but may still absorb volatile substances owing to its high surface area.

Source and Preparation

Hydrophobic colloidal silica is prepared by the flame hydrolysis of chlorosilanes, such as silicon tetrachloride, at &#; using a hydrogen-oxygen flame. It is rapidly cooled to create an amorphous product and immediately treated with dichlorodimethyl silane in a fluid bed reactor.The resulting surface is covered with dimethylsilyl groups. Aerosil R972 is manufactured by modifying the surface of Aerosil 130 and thus has the same primary particle size and surface area, but the density of silanol groups is reduced from approximately 2.0 SiOH/nm2 to 0.75 SiOH/nm2. .

Applications

Hydrophobic colloidal silica has nano-sized primary particles and a large specific surface area, which provide desirable flow characteristics in dry powders used in tableting and capsule filling. The hydrophobic grades absorb less moisture and may offer an advantage in moisture-sensitive formulations. Hydrophobic colloidal silica is also used to thixotropically control viscosity, to thicken and stabilize emulsions, or as a suspending agent in gels and semisolid preparations. Hydrophobic colloidal silica has a less pronounced effect on solution viscosity but can thicken and stabilize the oil phase of a water-oil emulsion.With other ingredients of similar refractive index, transparent gels may be formed. Generally, the uses and ranges of hydrophobic colloidal silica are similar to the concentrations used of the standard hydrophilic colloidal silicon dioxide.

Safety

The safety profile of hydrophobic colloidal silica is the same as for the hydrophilic silica types, as the modified silica surface does not significantly alter the toxicological properties. LD50 (rat, IV): 0.015 g/kg

Incompatibilities

Use of the hydrophobic colloidal silica Aerosil R972 reduces the strength of starch-based tablets.

Hydrophobic silicas comprise a unique group of materials that feature many types of advantageous properties and attributes. Their features make them suitable for a wide range of applications, including sealants, greases, adhesives, processing aids, and personal care products, among many others.

This material functions as a kind of anti-caking substance to eliminate, reduce, or mitigate the risk of hardening or &#;caking&#; within powders. It achieves this through moisture control (e.g. repellency) that helps to keep the particles consistently defined and separate, facilitating the free-flow of the powder.

Benefits of Using Hydrophobic Silica

If you&#;re considering hydrophobic silica, this material features numerous benefits that make it crucial for an array of compounds. These key advantages include:

• Adsorbent &#; Can adsorb liquids, solids, and gasses to create powder from liquids and pastes
• Anti-Blocking &#; Keeps film sheets separate and prevents sticking
• Anti-Sagging &#; Keeps wet coatings or paints from running or drooping
• Anti-Setoff &#; Prevents the potential inadvertent transfer of ink between printed pages known as setoff
• Anti-Setting &#; Helps increase the amount of time it takes for paint and pigments to dry on metallic and other surfaces when used with certain chemicals
• Free Flow of Powders &#; Functions as an anti-caking agent that keeps powders from hardening or caking
• Foam Control &#; Decreases foam levels or minimizes foam buildup
• Hydrophobicity Control &#; Serves as a natural water repellent that causes water to form droplets
• Mechanical and Optical Properties Improvements &#; Improves the transparency, clarity, and durability, among other material qualities
• Reinforcement &#; Provides reinforcement for some materials&#; elastomeric properties
• Pigment Stabilization and Dispersion &#; Facilitates the reliable application of certain types of complex pigments
• Print Definition &#; Reduces the risk of smudging, runoff, and other issues that could otherwise compromise print clarity and definition
• Processability Improvements &#; Enables increased processing along with application precision
• Rheology Control &#; Maintains the consistency of products throughout containers or batches
• Thickening &#; Increases the thickness of sealants, pigments, adhesives, and other types of liquid products to help improve application control and prevent running
• Thixotropy &#; Thins compounds that are normally thicker, specifically through stirring, shaking, or disturbing these compounds using other methods
• Suspension and Stability Behavior &#; Helps stabilize complex liquids while evenly suspending ingredient mixtures in batches

Hydrophobic Silica Free Flow Applications

Hydrophobic silica allows for the free flow and storage of a variety of powdered products, which are often prone to caking and hardening. The consensus for why this material has this effect is that hydrophobic silica forms a mono-particle silica layer around the particles within the powder. Subsequently, this layer helps reduce any &#;inner friction&#; that could otherwise develop, creating a kind of ball-bearing effect. In turn, applications benefit from increased consistency of product throughout batches, minimizing the risk of potential issues during processing.

Many different industries use hydrophobic silica across a range of products and applications. Some of the different products that utilize hydrophobic silica include:

• Coatings and paint
• Animal nutrition and feed
• Printing inks
• Toners
• Powdered defoamers and antifoams
• PVC-based plastics
• Pharmaceuticals and cosmetics
• Tablet powder blends
• Plastic powders
• Fire extinguisher powder
• Polyester resins and gel coats

Industry Example: Tire Recycling

Hundreds of millions of tires are disposed of every year. If they are not recycled or reused, this can have a significant negative effect on the environment.

The use of hydrophobic silica can help lessen the environmental impact of tire disposal by allowing for a more efficient recycling process. Specifically, hydrophobic silica helps during the grinding of the recycled tires into progressively smaller-sized granules. It assists with the free flow and particle screening of the granules, and imparts water repellency to help with moisture control.

Hydrophobic Silica Products from Applied Material Solutions

When selecting a hydrophobic silica, turn to Applied Material Solutions. We offer a wide variety of options, including fumed and precipitated products.

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For more information about our silica products and other solutions, Contact Applied Material Solutions today or call our offices at 262-723-.

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