Rubber Field Info

Rubber Field Info

Test Method for Silica

White carbon black, also known as silica, is a widely used reinforcing agent in colored rubber products. It is named “white carbon black” due to its appearance as a white powder, granules, or solid substance. The primary component of white carbon black is silica, which gives rise to two main types: precipitated hydrated silica (precipitated silica) and fumed silica.

These two forms of silica have distinct applications in the rubber industry. Precipitated silica is particularly suitable for the production of colored or white rubber products such as tires, rubber shoes, rubber tubes, tapes, heat-resistant gaskets, and medical supplies. On the other hand, fumed silica finds its main use in the manufacturing of silicone rubber. Additionally, it serves as a vital reinforcing agent for V-belts, rubber rollers, rubber tubes, cables, oil seals, and foaming products.

Silica Testing Parameters

Test parameters for precipitated silica (precipitated silica hydrate) 

Precipitated silica, with a chemical formula of SiO2 · nH2O, undergoes various test parameters to evaluate its quality. The key test items for precipitated silica include silica content, color, residue on a 45 μm sieve, loss on heating, loss on ignition, pH value, total copper content, total manganese content, total iron content, dibutyl phthalate absorption value, water-soluble matter, stress at 300% constant elongation, stress at 500% constant elongation, tensile strength, elongation at break, physical form, dispersion, specific surface area, and other relevant indicators. These parameters help assess the purity, physical properties, and performance characteristics of precipitated silica.

Test parameters for high dispersion precipitated silica (high dispersion precipitated hydrated silica)

The test parameters for high dispersion precipitated silica are generally similar to those of regular precipitated silica. However, additional test items are included to evaluate the technical indexes and typical values specific to high dispersion precipitated silica. Therefore, the technical specifications for high dispersion precipitated silica require the measurement of two additional parameters: median particle size and particle proportion. In addition to these, the typical values are determined by conducting tests for total surface area, CTAB adsorption specific surface area, and dispersion. These parameters provide valuable information regarding the particle characteristics and dispersion properties of high dispersion precipitated silica.

Test parameters for fumed silica (fumed silica)

Fumed silica is expected to have a fluffy white powder appearance. The specific test parameters primarily involve the nitrogen adsorption specific surface area, loss on ignition, silicon dioxide content, aluminum oxide content, titanium dioxide content, iron oxide content, carbon content, chloride content, pH value of suspension, volatile matter at 105 ℃, bulk density, 45 μm sieve residue, and other relevant indicators. These test items are essential for evaluating the quality and characteristics of fumed silica, ensuring it meets the required specifications.

Silica Testing Standards

1). The testing standards of silica products mainly include


GB / T 20020-2013 Fumed silica 

GB / T 32678-2016 rubber compounding agent highly dispersed precipitated hydrated silica

Hg / T 3061-2009 rubber compounding agent precipitated hydrated silica

 

2). The national standard of silica for rubber mainly includes:

 

GB / T 23656-2016 rubber compounding agents Determination of specific surface area of precipitated hydrated silica CTAB method

GB / T 28600-2012 rubber compounding agents Determination of average pore size of precipitated hydrated silica

GB/T 28601-2012 determination of gel content of precipitated hydrated silica by rubber compounding agent

GB / T 32698-2016 rubber compounding agents – Determination of particle size distribution of precipitated hydrated silica – laser diffraction method

GB / T 34698-2017 rubber compounding agents Determination of water soluble matter content of precipitated hydrated silica conductivity method

GB / T 36764-2018 rubber compounding agent precipitated hydrated silica inductively coupled plasma atomic emission spectrometric determination of heavy metal content

 

3. The industrial standards of silica test methods for rubber mainly include:


Hg / T 2404-2008 Identification of precipitated hydrated silica in styrene butadiene rubber 

Hg / T 3062-2008 rubber compounding agent – Determination of silica content in precipitated hydrated silica dry samples

Hg / T 3063-2008 comparison of color of precipitated hydrated silica in rubber compounding agent

Hg / T 3064-2008 rubber compounding agent Determination of precipitated hydrated silica 45 μ m sieve residue

Hg / T 3065-2008 rubber compounding agent Determination of heating loss of precipitated hydrated silica

Hg / T 3066-2008 rubber compounding agent – Determination of ignition loss of precipitated hydrated silica dry sample

Hg / T 3067-2008 rubber compounding agent Determination of pH value of precipitated hydrated silica water suspension

Hg / T 3068-2008 rubber compounding agent Determination of total copper content of precipitated hydrated silica

Hg / T 3069-2008 rubber compounding agent Determination of total manganese content of precipitated hydrated silica

Hg / T 3070-2008 rubber compounding agent Determination of total iron content of precipitated hydrated silica

Hg / T 3071-2008 rubber compounding agent Determination of refractive index of precipitated hydrated silica

Hg / T 3072-2008 rubber compounding agent Determination of absorption value of precipitated hydrated silica dibutyl phthalate (DBP)

Hg / T 3073-1999 rubber compounding agent Determination of specific surface area of precipitated hydrated silica nitrogen adsorption method

Hg / T 3748-2014 rubber compounding agents Determination of water soluble matter content of precipitated hydrated silica cold extraction method